Michael Von Cotta- Schönberg

Silvio Enea

; Piccolomini

Sylvius Aeneas

Silvius Aeneas

Piccolomini

On his way to the Congress of Mantua, in 1459, Pius II stayed for two months in his native city of Siena. Presenting the papal Golden Rose to the city government on Laetare Sunday in Lent, he took the opportunity to give an oration in praise of the city (laudatio urbis), commenting on its nobility, its Roman origins, its splendid buildings, and its eminent men in various fields as well as its holy men and women. Among the last were Catherine of Siena whom he would later canonize.

Editor/translator

Michael v. Cotta-Schönberg Mag. Art. (University of Copenhagen) Bachelier en Philosophie (Université de Louvain) Emeritus Deputy Director / The Royal Library, Copenhagen Emeritus University Librarian / University of Copenhagen ORCID identity: 000-0001-8499-4142 e-mail: typsita@gmail.com

Foreword

In 2007, I undertook a project of publishing the Latin texts with English translations of the orations of Enea Silvio Piccolomini / Pope Pius II. Altogether 80 1 orations (including papal responses to ambassadorial addresses) are extant today, though more may still be held, unrecognized, in libraries and archives.

At a later stage the project was expanded to include ambassadors' orations to the pope, of which about 40 are presently known.

I do not, actually, plan to publish further versions of the present volume, but I do reserve the option in case I -during my future studies -come across other manuscripts containing interesting versions of the oration or if important new research data on the subject matter are published, making it appropriate to modify or expand the present text. It will therefore always be useful to check if a later version than the one the reader may have previously found via the Internet is available.

I shall much appreciate to be notified by readers who discover errors and problems in the text and translation or unrecognized quotations.

12 September 2019 MCS 1 81 orations, if the "Cum animadverto" is counted is a Piccolomini-oration, see oration "Quam laetus" [18], Appendix

Table of volumes in Collected Orations of Pope Pius II. 12 vols. Edited and translated by Michael von Cotta-Schönberg

I. INTRODUCTION 1. Context 1

On his way to the Congress of Mantua, Pius II spent two months in his beloved city Siena, from February to April. His intention was to benefit his city in three ways: by raising the city's prestige through an extended papal presence, by creating harmony in the body politic through the restoration of the city's noble families to its government; and by providing economic stimulus through the presence of the papal court and its many visitors, ambassadors and others.

The pope resided in the city during Lent. On the third Lenten Sunday, Laetare, the popes traditionally bestowed a Golden Rose on the highest-ranking guest present, as a sign of great papal favour. In a probably carefully planned show of favour and gratitude towards the city, the pope this year decided to bestow the Golden Rose on the City of Siena. Undoubtedly, the pope's feelings towards Siena were quite genuine, but he also hoped that the gesture would create goodwill in the city's ruling classes which would favour his political project concerning the reintegration of the nobles into the city government. 2

The city government was, of course, honoured and flattered by the pope's gesture, but on the issue of the nobility they still fiercely resisted the pope's wishes.

In his Commentarii, Pius wrote about the event:

Soon afterwards fell the Lenten Sunday known as the Sunday of the Rose. In order to honor the city, the pope himself conferred the traditional gift of a golden rose on the Prior of Priors, an office that is held for three days. Then he delivered an oration in praise of Siena and ordered the cardinals to escort the recipient of the rose to the palace. The prior, who happened to belong to a family of the Reformers 3 named Buoninsegni, came last in the procession flanked by two cardinals. [START_REF] Martini | one of the masters of the Sienese school of painting 5 Giotto di Bondone (ca. 1267-1337[END_REF] The event is not mentioned by Pius' two contemporary biographers, Campano and Platina.

Themes

First, Pius describes the papal tradition of bestowing a Golden Rose on an eminent participant in the papal Laetare Sunday liturgy and motivates the choice of the City of Siena as this year's recipient. This choice provides him with the opportunity to give a laudatio urbis, after classical models.

Secondly, he gives a characterization of Siena as belonging to the middle league of Italian powers, neither in the top like Milan or Naples or at the bottom, but in the middle -just as the rose grows neither at the top of trees or lies on the ground as some plants.

Thirdly, he mentions the history of the city, claiming Roman antecedents -mixed with Gaulish.

Fourthly, he lists and briefly describes a number of eminent citizens of Siena, within the fields of war, law, medicine and the arts. Among the city's holy men and women he mentions Catherine of Siena whom he would later himself canonize, 1 and Saint Bernardino of Siena whom he had met personally.

Date, place, audience and format

The date was 15 March 1459, Laetare Sunday.

The venue was the cathedral of Siena, see sect. 2 of the oration where Pius directly refers to that Church: ornatissima temple ipsi cernitis, et hoc praesertim gloriosae virginis dedicatum …

The audience consisted of the cardinals, curials and ambassadors present in Siena as well as the Sienese magnates and people, including, presumably, a number of Piccolomini relatives.

The format was a papal oration from the throne.

1 See oration "Catherinam Senensem" [62]

Text 1

The oration is included in a special Collection of Pius II's Responses from 1459 and 1460, largely consisting of responses to addresses by ambassadors,2 extant in at least four manuscripts.

Manuscripts

• Lucca / Biblioteca Capitolare Feliniana 544, ff. 176r-177r (G) *3

• Roma / Archivio Segreto Vaticano Arm. XXXII 1, ff. 56r-59r (J) *

• Roma / Biblioteca Apostolica Vaticana Barb. lat. 1499, ff. 67v-70v Chisianus J.VII.251, ff. 171v-174r (H)

The Chisianus is the eldest of the three and identical with or very close to the oration as actually delivered by Pius, but actually there are only small differences between the texts in the three manuscripts.

Editions

The oration has seen at least two editions4 :

• Pius II: Orationes politicae et ecclesiasticae. Ed. Giovanni Domenico Mansi. 3 vols. Lucca: Benedini, 1755-1759. / T. II, pp.

1-4 [Edition based on the manuscript in Lucca (G)]

• Gigli, Girolamo: Il diario Senese. 2 nd ed. Tom. I. Siena, 1854 / pp. 436-439 (GI) 1 [According to Gigli himself this edition was based on a manuscript from the collection of Queen Christina of Sweden.]

Present edition

For principles of edition (incl. orthography) and translation, see Collected Orations of Enea Silvio Piccolomini / Pope Pius II, vol. 1, ch. 9-10.

Text:

The present edition is based on the manuscripts from Lucca, the Archivio Segreto Vaticano and the Chisianus and the text published by Gigli, with the Chisianus as the lead text.

Pagination:

Pagination is from the lead manuscript.

Sources 2

In this oration, no direct and indirect quotations have been identified.

Bibliography

Ady, Cecilia M.: Pius II (AEneas Silvius Piccolomini) -the Humanist Pope. London, 1913

Tradition of the Golden Rose

[1] An ancient custom of our forefathers, diligently kept until our own times, is that on the solemn feast we are celebrating today a golden rose be given to the participant who is first among all in nobility and virtue as well as in faith, dedication and devotion towards the Roman Church. 1 For as the rose, made of the purest gold, the most precious of metals, is preferred to all other flowers because of its exquisite beauty, thus the man considered worthy of this gift must excel among men. Since the old ones are undoubtedly our guides concerning virtuous life, we should follow in their footsteps. So, today we shall observe ancient custom. But considering those who are assembled here, we do not presume to prefer one to the others. Before Us we see the legates of kings, princes and peoples, [all] with excellent merits towards the Roman Church, the Catholic Faith and Christian Religion, and it would not be easy to single out any one of them.

Motivation for bestowing the Golden Rose upon Siena

[2] But since, today, we are in the gracious city of Siena, Our own sweet fatherland, Our birth place that gave us flesh and bones, a noble city very dear to the Apostolic See, We consider it fitting to distinguish its pious and religious people with this gift. This people may not surpass others peoples as gold surpasses other metals and roses surpass other flowers. However, it is similar to the rose in that the rose grows from a bush: it does not rise from the grassy ground nor hangs from tall trees, but has a place in the middle between the lowest and the highest. In the same way, the Republic of Siena has a place in the middle of the Italian powers. Some come before it, and some come after. But with regard to virtue2 , loyalty, religiosity, piety and all the other good qualities3 it is second to none. It is therefore quite fitting to bestow upon it the splendour of gold and the fragrance of the rose.

[3] Quae sit vero nobilitas hujus urbis, quae praestantia, quae gloria licet paucis commemorare, ut intelligant omnes donandam huic populo rosam non carnem nobis aut sanguinem revelasse, sed ipsam prorsus rationem

Nobility of Siena

[3] Let us dwell briefly on the nobility of this city its excellence, and glory so that all may understand that it is not personal or familial ties, but reason that has inspired Us to give the rose to this people. You can see for yourselves the splendour of the city, the magnificence of its buildings, the noble palaces and the grand temples, especially this one dedicated to the glorious Virgin 1 , which may not have its equal in all of Europe.

History of Siena

The people of Siena is said to be of mixed origin, going back both to the Romans and to the Gauls. 2 The statue of the she-wolf with the two twin boys points to the Roman parentage 3 whereas the name of the city points to its Gallic origins. According to local tradition, when the Senones from Gaul had set Rome on fire and were put to flight by Camillus, remnants from both armies settled in this place and founded the City of Siena. Often the neighbouring peoples [START_REF] Martini | one of the masters of the Sienese school of painting 5 Giotto di Bondone (ca. 1267-1337[END_REF] plotted against them and inflicted many injuries upon them, but they were never able to overcome them. Sometimes the people defended itself successfully with their own forces, sometimes they repelled their enemies with external aid, and sometimes they preserved their liberty more with help from God than by human endeavour. For this reason Siena has, in a public document, dedicated itself to Blessed Mary, Mother of the Lord, and since then it has been called the City of the Virgin. 1 Evidently, the ceremony took place in the cathedral of Siena, dedicated to the Holy Virgin 2 Siena was first settled by an Etruscan tribe, the Saina (ca. 900-400 BC). In the time of the Emperor Augustus, a Roman town called Saena Julia was founded at the site. The connection to the Senones from Gaul is defended by some archaeologists 3 Lupa is the quarter of the city situated to the north of the Piazza del Campo. Lupa's symbol is a female wolf nursing twins. Its colors are black and white, trimmed with orange. The she-wolf of this contrada may refer to the legend that Siena was founded by Senius, the son of Remus who, along with his twin Romulus, was raised by a wolf. Because of this, Lupa 's sister city is Rome [START_REF] Martini | one of the masters of the Sienese school of painting 5 Giotto di Bondone (ca. 1267-1337[END_REF] And first among them Florence 20 [4] Fuerunt hic et hodie sunt complures 1

Holy men and women

[5] But such matters are human and transitory. However, many Sienese have also attained what is solid and eternal through their piety and moral life. In a former period, Pier Pettinaio1 was known for his great holiness. When he sold his combs, he only mentioned the price once and then pointed to his closed mouth. Catherine,2 that excellent woman, urged the pope, then residing in Avignon, to return to Rome, and her reputation for holiness was enough to convince him. Many of you knew Bernardino3 whose sermons were heard by great crowds as if he was the Apostle Paul himself or an angel sent from Heaven. But all the famous people of this city are surpassed in fame and glory by Alexander III4 : though he took over the government of the Roman See during a schism and was hard-pressed by the mighty emperor,5 driven out of Rome, and forced to go begging all over Italy and France, he was victorious in the end, brought the Church back to unity, forced the ferocious enemy, who had been defeated both on land and at sea, to sue for mercy, [START_REF]Vestrae igitur civitati, viri Senenses, de Romana ecclesia optime merenti 1 , tot claris illustratae viris[END_REF] and rewarded his Venetian allies with exceptional privileges. If only the Divine Piety would grant Us a similar success against the Turks for the protection of the Christian cause, then We too could add something to the honour of Our country.

Conclusion

[6] Men of Siena, on the advice and with the assent of Our venerable brothers, the cardinals of the Holy Roman Church, We bestow on your city, so well deserved of the Roman Church and so distinguished by famous men and splendid ornaments, this golden rose as a pledge of Our love and a testimony of your rectitude. Go now and follow the path of your forefathers: do works of piety, extol religion, honour the Roman Church, and show kindness and justice to all, so that as your forefathers made the City of Siena famous by their good works,1 you too will distinguish it with your glorious deeds.

Table of contents

 of

	I.	INTRODUCTION
	1. Context
	2. Themes
	3. Text
		3.1. Manuscripts
		3.2. Editions
		3.3. Present edition
	4. Date, place, audience and format
	5. Sources
	6. Bibliography
	7. Sigla and abbreviations
	II.	TEXT AND TRANSLATION
	1.	Tradition of the Golden Rose [1]
	2.	Motivation for bestowing the Golden Rose upon Siena [2]
	3.	Nobility of Siena [3]
	4.	History of Siena [3]
	5.	Eminent citizens of Siena [4-5]
		5.1. Nobles [4]
		5.2. Military men [4]
		5.3. Law men [4]
		5.4. Medical men [4]
		5.5. Philosophers, poets, and orators [4]
		5.6. Artists [4]
		5.7. Holy men and women [5]
	6.	Conclusion [6]

  Les Lettres et la Tiare. E.S. Piccolomini -un humaniste au XVe siècle. Paris, 2012. (Etudes et Essais sur la Renaissance; 98) Strnad, Alfred A.: Johannes Hinderbachs Obedienz-Ansprache vor Papst Pius II -Päpstliche und kaiserliche Politik in der Mitte des Quattrocento.In:[1] {172r} Vetus majorum nostrorum consuetudo fuit, ad haec usque tempora diligenter observata, in ea solemnitate, quam hodie repraesentamus, rosam auream inter celebrandum ei ex circumstantibus dono donare, qui cum nobilitate ac virtute praestaret 2 , tum fide, studio ac devotione erga Romanam ecclesiam ceteros anteiret. Nam sicut rosa ipsa ex auro purissimo, quod metallis omnibus anteponitur, composita est et pro forma ejus eximia cunctis praefertur floribus, ita et eum inter alios mortales excellere oportet, qui hoc dono dignus ducitur. Sequi nos veterum vestigia convenit, quos recte vivendi duces fuisse non est ambiguum. Parere igitur hodie inveteratis moribus placet. Sed circumspicientes 3 astantem coronam non sumimus hoc judicium, ut unum aliquem ceteris praeferamus. Cernimus hinc atque inde legatos regum, et principum, et populorum de Romana ecclesia, de fide catholica, de religione Christiana optime meritorum, nec facile alterum alteri proposuerimus.

	Allegretti, Allegretto: Diari delle cose Sanesi del suo tempo [Ephemerides Senenses ab anno MCCCCL usque ad MCCCCXCVI, italico sermone scriptae]. Milano, 1733. (Rerum Italicarum Scriptores; 23) Boulting, William: Aeneas Silvius (Enea Silvio de' Piccolomini -Pius II). Orator, man of letters, Stolf, Serge: Römische historische Mitteilungen, 10 statesman, and pope. London, 1908 (1966/1967) 41-183
	Cornides, Elisabeth: Rose und Schwert im päpstlichen Zeremoniell von den Anfängen bis zum Voigt, Georg: Enea Silvio de' Piccolomini als Papst Pius der Zweite und sein Zeitalter. 3 vols. Berlin, Pontifikat Gregors XIII. Wien, 1967 1856-63
	Feccini, Tommaso: Cronache senesi. Eds. A. Lisini & F. Iacometti. Bologna 1931-1939. (Rerum Zimolo, Giulio C. (ed.): Le vite di Pio II di Giovanni Antonio Campano e Bartolomeo Platina. Italicarum Scriptores; 15.6) [Incomplete] Bologna, 1964. (Rerum Italicarum Scriptores; t. III, p. II)
	7. Sigla and abbreviations
	Lucca: Redaktion ed. von Julia Knödler. Teil 2: 2./3, ed. Martin Wagendorfer. 2 vols. Hannover, Benedini, 1755-1759 2009. (Monumenta Germaniae Historica. Scriptores Rerum Germanicarum. Nova Series;
	• Collected Orations of Pope Pius II. Ed. and transl. by Michael v. Cotta-Schönberg. 12 vols. 24)
	1 no title H; pontificia omit. J, GI 2019-2020 HB = Aeneas Silvius Piccolomini: Historia Bohemica. Herausg. J. Hejnic & H. Rothe. 2 vols. Köln, 2 pietate GI
	Reinhardt, Volker: Pius II. Piccolomini -Der Papst, mit dem die Renaissance begann. München, 3 suspicientes GI 2005. (Bausteine zur slavischen Philologie und Kulturgeschichte. Neue Folge. Reihe B; 20) 4 ac G
	2013

1 Not mentioned by Strnad 2 On Piccolomini's use of sources in general, see Collected orations of Pope Pius II, ch. 8. Gigli, Girolamo: Il diario Senese. 2 nd ed. Tom. I. Siena: Landi & Alessandri, 1854, pp. 436-439 Mitchell, R.J.: The Laurels and the Tiara -Pope Pius II, 1458-1464. London, 1962 Pastor, Ludwig: Geschichte der Päpste im Zeitalter der Renaissance. 16 vols. Freiburg i.B., 1886-1933 Pius II: Commentarii rerum memorabilium quae suis temporibus contigerunt. [1464] • Commentarii rervm memorabilivm que svis temporibus contigervnt. Ed. A van Heck. 2 vols. Città del Vaticano, 1984. (Studi e testi; 312-313) • Commentaries. Ed. M. Meserve and M. Simonetta. Vols. 1 ff. Cambridge, MA, 2003 ff. Pius II: Orationes. [1436-1464] • Pius II: Orationes politicae et ecclesiasticae. Ed. Giovanni Domenico Mansi. 3 vols.. G = Lucca / Biblioteca Capitolare Feliniana / 544 H = Roma / Biblioteca Apostolica Vaticana / Chisianus J.VII.251 J = Roma / Achivio Segreto Vaticano / Arm. XXXII 1 GI = Gigli, Girolamo: Il diario Senese. 2 nd ed. Tom. I. Siena: Landi & Alessandri, 1854 Abbreviations CO = Pius II: Commentarii rerum memorabilium quae suis temporibus contigerunt. [1464] HA = Eneas Silvius Piccolomini: Historia Austrialis. Teil 1: Einleitung von Martin Wagendorfer. 1. MA = Pius II: Orationes politicae et ecclesiasticae. Ed. Giovanni Domenico Mansi. 3 vols. Lucca: Benedini, 1755-1759 De rosa aurea pontificia 1 [2] Sed cum simus hodie in alma urbe Senensi, in dulcissima patria nostra, in solo natali, ex quo carnem atque ossa suscepimus, in civitate nobili et apostolicae sedis amantissima, haud ab re arbitrati sumus pium et 4 religiosum populum hoc munere exornare, qui etsi non excellit alios, ut aurum metalla reliqua, et rosa flores universos, in eo tamen rosae comparari potest, quod sicut rosa ex arbusto gignitur, neque humi jacet {172v} in herba, neque sublimi pendet ex arbore 5 , sed media inter ima sedet et alta, ita respublica Senensis inter alios Italiae potentatus mediocritatem quandam obtinet. Sunt enim qui praecedunt et sequuntur. Ceterum circa bonos mores 6 , fidem, religionem, pietatem ceterasque bonas artes nulli omnino cedit. Quibus 7 ex rebus et splendorem auri et bene olentem rosae odorem non inconcinne ei appropriare 8 licet. 5 neque … arbore omit. G

  1 persuasisse: urbis splendorem, aedificiorum magnificentiam, nobilissimas aedes, ornatissima templa ipsi cernitis, et hoc praesertim gloriosae virgini dedicatum, cui non facile aliud tota Europa 2 praeferatur. Populi hujus origo ex Romanis ac 3 Gallis mixta refertur. Parentes esse Romanos lupae insigne et gemelli testantur infantes; Gallicam progeniem nomen indicat urbis. Fama 4 est, fugatis a Camillo Gallis Senonibus, qui Romam incenderant, hoc loco nonnullas exercitus utriusque reliquias consedisse, et ab his Senam conditam. Multae huic urbi a vicinis populis insidiae paratae, multae illatae molestiae; numquam tamen ab his subjici potuit. Defendit se modo suis armis, modo imploratis auxilia hostes repulit, nonnumquam 5 divino magis[START_REF]Vestrae igitur civitati, viri Senenses, de Romana ecclesia optime merenti 1 , tot claris illustratae viris[END_REF] auxilio quam humana ope suam libertatem tutata est 7 . Ob quam rem publico chirographo beatae {173r} Mariae, matri domini, sese traditit, atque hinc civitas virginis appellata.

	1 rationi G
	2 tota Europa : per totam Europam GI
	3 et G

[START_REF] Martini | one of the masters of the Sienese school of painting 5 Giotto di Bondone (ca. 1267-1337[END_REF]

Origo Senarum in marg. G 5 numquam GI; tamen add. G 6 minus GI 7 ut add. GI

  nobilium familiae, ingenuis moribus et singularibus virtutibus praepollentes, a quibus altae, quas cernitis, turres erectae et antiqua constructa palatia sunt. Claruerunt et in armis et in litteris non pauci Senenses. Duces copiarum insignes prior aetas plures novit, inter quos Salvanius 2 ille, qui Montis Aperti victoriam aperuit clarus est habitus. Nostra memoria Petrinus Salimbernius 3 , Nannes Piccolomineus 4 , Antonius Rufaldus illustre nomen habuere. In scientia juris clara est fama Friderici, cujus consilia multi sequuntur; Johannes Pagliarensis 5 omne corpus juris memoriae 6 condidisse creditus est. Fuit et Richardus Petronius 7 cardinalis magni nominis, cui curam condendi Sexti decretalium libri sancta sedes apostolica demandavit. [cont.] In medicinis omnium princeps suae aetatis habitus est Ugo Bentius 1 . Sunt et hodie complures, qui et civilem sapientiam et arcana philosophorum et poetarum 2 et oratorum litteras non aliter callent, quam si conditores ipsi earum scientiarum fuissent. Nomina praetermittimus ne generemus invidiam. In arte pictoria Simonettum 3 Senensem Jotho Florentino non inferiorem fuisse tradunt. Sculpere atque aera ducere et in materia musaicum repraesentare Senensi industriae proprium fuit.[START_REF] Martini | one of the masters of the Sienese school of painting 5 Giotto di Bondone (ca. 1267-1337[END_REF] Mortalia haec atque caduca. Illud vero stabile atque immortale, quod plurimi Senenses assecuti sunt cultu religionis et integritate vitae. Petrum Pectinarium insigni {173r} sanctitate cognovit antiquitas, qui cum pectines venales exponeret, uno verbo pretium dixit exin digito labra 1 conclusit. Catherina, excellens mulier, papae in Avenione moranti 2 Romam repetere suasit, et sola sanctitatis opinione pontificem movit. Bernardinum multi ex vobis novere, quem veluti Paulum apostolum aut angelum caelo missum frequentes populi praedicantem audivere. Sed omnium, qui ex hac urbe claruerunt, famam ac gloriam superavit Alexander cognomento tertius, qui quamvis in schismate Romanae sedis gubernacula 3 suscepisset et ab imperatore potentissimo vexaretur, e Roma ejectus, per Italiam ac Galliam mendicare auxilia cogeretur, victor tamen propositi et ecclesiam ad unitatem reduxit, et ferocientem hostem terra marique victum petere veniam compulit, et adjutores Venetos singularibus privilegiis honestavit. Utinam parem[START_REF] Martini | one of the masters of the Sienese school of painting 5 Giotto di Bondone (ca. 1267-1337[END_REF] nobis divina pietas adversus Turcos 5 , pro tutela Christiani nominis felicitatem impartiatur, ut et nos quoque ad laudem patriae 6 tandem aliquid adjiciamus.

	1 quamplures GI 2 Silvanius G, H; Salvanus GI 3 Salimbenius GI 4 Piccolominus G; Picolhominus H [5] 1 labia GI 2 morante G [4 cont.] 1 Bensius GI 3 gubernaculum
	5 Paglarensis G, H; Pagliaresius GI 2 prophetarum G 4 pacem GI
	6 memoria GI 3 Simonetum G, H 5 Turcas GI
	7 Petronus GI 4 tradunt … fuit omit. J, GI 6 primae GI

Concerning the textual transmission of Pius II´s orations, see Collected orations of Pope Pius, vol. 1, ch. 5

See Collected Orations of Pope Pius II, vol.1, sect. 5.2.1

Manuscripts for which an orthographical profile is given in Collected orations of Pope Pius II, vol. 11, are marked with an asterisk

Strnad, p. 99, n. 153

bonos mores : mores bonos J

et add. J

appropinquare GI

The papal custom of presenting a golden rose, blessed on Laetare Sunday in Lent, to a deserving prince goes back to the early medieval papacy

"bonos mores"

"bonas artes": in other contexts used for the liberal arts

Pier Pettinaio [Pietro da Campi] (1180-1289): Sienese merchant (combs), reputed for his holiness. The notion of only opening one's mouth once during a sales transaction had been mentioned by Piccolomini 13 years before, in the oration "Non habet me dubium"[START_REF]Vestrae igitur civitati, viri Senenses, de Romana ecclesia optime merenti 1 , tot claris illustratae viris[END_REF], which was really a treatise on Christian life and morality: When selling, one should be open, sincere, just, and good, conceal nothing -for the sake of personal gain -that the buyer should know, and avoid deceit, dissimulation, and deception. In selling and buying you should speak very little and if possible only once [sect. 131]. So, the concept of not praising one's wares and performing lengthy transactions and haggling when selling may have been a medieval notion connected with the morals of commerce

Catherine of Siena [Caterina di Siena] (1347-1380): Saint

Bernardino da Siena [Bernardino degli Albizeschi] (1380-1444): Franciscan preacher from a noble family in Sienese territory. Saint

Alexander III [Roland of Siena] (ca. 1100-1180): Pope from 1159 to his death

Friedrich I Barbarossa (1122-1190): Holy Roman Emperor from 1155 until his death

Peace of Venice, 1177

"bonis artibus"

Eminent citizens of Siena

5.1. Nobles [4] The tall towers and the old palaces you see here were built formerly by a number of noble families which are still here today, 1 distinguished by their excellent character and outstanding virtues.

Military men

Many Sienese are famous for their military skills or their scholarship.

Among the distinguished captains of former times was that Salvani 2 who is known for his victory at the Monte Aperto. 3 In our own time, Petrino Salimbeni, [START_REF] Martini | one of the masters of the Sienese school of painting 5 Giotto di Bondone (ca. 1267-1337[END_REF] Nanni Piccolomini, and Antonio Rufaldo 5 enjoyed a great reputation.

Law men

In the field of law, Federigo 6 is quite famous and has many followers. Giovanni Pagliarese 7 is believed to have learnt the entre corpus juris by heart. Cardinal Riccardo Petroni 8 was greatly admired and was asked by the Holy See to compile the Liber Sextus Decretalium. 9 [cont.]

1 One of the old noble families being the Piccolomini, of course 2 Provenzano Salvani (ca. 1220 -ca. 1269): Italian condottiero. Head of the Ghibelline party in Siena 3 Battle of Montaperto, some kilometers south if Siena, on 4 September 1259. The battle was between the Ghibelline troops of Siena and the Guelf troops of Florence. The Sienese troops were victorious [START_REF] Martini | one of the masters of the Sienese school of painting 5 Giotto di Bondone (ca. 1267-1337[END_REF] The Salimbeni were an old and important family in Siena 5 Not identified [START_REF]Vestrae igitur civitati, viri Senenses, de Romana ecclesia optime merenti 1 , tot claris illustratae viris[END_REF] Federigo Petrucci, jurist from Siena.


Julien Richirt
email: richirt.julien@gmail.com

Eric Goberville
email: eric.goberville@upmc.fr

Vania Ruiz-Gonzalez

Benoît Sautour

Local changes in copepod composition and diversity in two coastal 2 systems of Western Europe 3 4 5 6

Keywords: copepod communities, long-term changes, diversity indices, coastal systems, multivariate 57 analysis

While long-term monitoring is essential to improve our knowledge of marine ecosystems health, 37 it remains challenging to summarise complex ecological data in order to characterise and understand 38 biodiversity trends. To compile monitoring data across large numbers of species, scientists and 39 policymakers mainly rely on diversity and species richness indices. This task may prove complicated 40 however, as many indices exist and no individual metric undoubtedly emerges as the best overall. Here, 41 using data from zooplankton surveys from 1998 to 2014, we examined year-to-year changes in copepod 42 communities in two littoral ecosystems of Western Europe -the Arcachon Bay and the Gironde estuary 43 -that share similar climate, but with different local ecological processes, especially hydrological 44 conditions. We tested the ability of commonly used α and ß-diversity metrics, such as species richness, 45 Pielou's evenness or Jaccard's index, to mirror year-to-year changes in species abundances and we 46 detected a synchronous change in both copepod abundances and α-diversity that took place circa 2005 47 in the two sites. In response to changes in environmental conditions such as nutrients, salinity, river 48 discharge or particulate matter, two opposite biodiversity trends were observed, with a decrease in 49 copepod diversity in the Arcachon Bay but an increase in the downstream part of the Gironde estuary. 50 Although diversity metrics allowed us to well detect trends, the use of multivariate approaches such as 51 principal component analysis provided important information on how and why diversity fluctuates. Our 52 study provides evidence that long-term monitoring programmes must be encouraged for optimising 53 management and conservation actions such as the Marine Strategy Framework Directive and that more 54 local comparative studies need to be initiated for better characterising diversity trajectories at very fine 55 scales at which ecologists often work.

Figures: 6 Coastal marine systems, which are among the most ecologically and economically important 61 ecosystems on the planet [START_REF] Harley | The impacts of climate change in coastal marine systems[END_REF], are known to be highly sensitive to climate fluctuations 62 and direct anthropogenic pressures [START_REF] Harley | The impacts of climate change in coastal marine systems[END_REF][START_REF] Goberville | Evaluation of coastal perturbations: a new 667 mathematical procedure to detect changes in the reference state of coastal systems[END_REF]. The impact of these 63 forcing is not restricted to a particular biological component but extends to all ecological units, affecting 64 marine biodiversity from phytoplankton to top predators [START_REF] Frederiksen | From plankton to 653 top predators: bottom-up control of a marine food web across four trophic levels[END_REF]Chaalali et al., 65 2013a), leading to alterations in the structure and functioning of coastal systems [START_REF] Chevillot | Global changes jeopardize the trophic carrying 620 capacity and functioning of estuarine ecosystems[END_REF],

66
with possible ramifications for the terrestrial realm [START_REF] Luczak | 715 Population dynamics in lesser black-backed gulls in the Netherlands support a North Sea regime 716 shift[END_REF]. For example, three decades of 67 observation have revealed synchronous climate, environmental and biological community shifts in the 68 San Francisco Bay [START_REF] Cloern | Biological communities in San Francisco Bay track 623 large-scale climate forcing over the North Pacific[END_REF]. In the Gironde estuary, large (e.g. the Atlantic Multidecadal 69 Oscillation) and regional (e.g. annual sea surface temperature and winds) climate-driven processes have 70 induced concomitant changes in hydrological and biological conditions, including abrupt modifications 71 in the composition and structure of pelagic communities (Chaalali et al., 2013a;[START_REF] Chevillot | Abrupt 616 shifts in the Gironde fish community: an indicator of ecological changes in an estuarine 617 ecosystem[END_REF].

72

Concurrently, habitat loss, overexploitation and pollution are major human threats that affect coastal 73 diversity [START_REF] Duffy | Envisioning a marine biodiversity observation network[END_REF][START_REF] Elahi | Recent 645 trends in local-scale marine biodiversity reflect community structure and human impacts[END_REF].

74

Global alteration of coastal ecosystems in recent decades has led policymakers to encourage 75 monitoring programs worldwide and estimating biodiversity appears as the most relevant way to 76 measure the status of ecological conditions [START_REF] Duffy | Envisioning a marine biodiversity observation network[END_REF][START_REF] Elahi | Recent 645 trends in local-scale marine biodiversity reflect community structure and human impacts[END_REF]. Long-term 77 observations are essential to disentangle natural variations from unusual or extreme events (Lovett et 78 al., 2007), to better capture the inherent variability and stochasticity associated to surveys and 79 ecosystems [START_REF] Kujala | Treatment of uncertainty in conservation under climate 693 change[END_REF][START_REF] Beaugrand | Quasi-deterministic responses of marine species to climate change[END_REF] and to identify the main forcing that can 80 affect ecosystems [START_REF] Goberville | Climate-driven changes in coastal marine 665 systems of Western Europe[END_REF]. To compile monitoring data across large numbers of species 81 and ecosystems, scientists and policymakers often rely on diversity indices [START_REF] Pereira | Essential biodiversity variables[END_REF], easy-82 to-implement measures of biodiversity for which the effort in calculation and computation is much less 83 cumbersome than multivariate approaches. These indices are also known to be appropriate tools for a 84 rapid and efficient communication between the scientific community, government agencies, funding 85 institutions and the general public (e.g. [START_REF] Lovett | Who needs environmental monitoring?[END_REF]. However, many metrics exist and none 86 emerges as the best overall [START_REF] Bandeira | Mathematical convergences of biodiversity 568 indices[END_REF] nor combines all different facets of diversity (Salas 87 et al., 2006;[START_REF] Rombouts | Evaluating marine ecosystem health: Case studies of indicators using direct observations 761 and modelling methods[END_REF]. Using a range of complementary indices enables to better evaluate 88 both the strengths and weaknesses of the different metrics in detecting changes over time (Rombouts et 89 al., 2013;[START_REF] Loiseau | Indices for assessing coral reef fish biodiversity: the need for a change 707 in habits[END_REF] or in assessing ecosystem status, when combined with relevant 90 indicator species [START_REF] Lindenmayer | 704 A new framework for selecting environmental surrogates[END_REF].

91

Copepods are ubiquitous and play pivotal roles in the functioning of marine systems and in 92 biogeochemical cycles (e.g. [START_REF] Richardson | In hot water: zooplankton and climate change[END_REF] even in low-diversity ecosystems [START_REF] Horváth | Opposing patterns 676 of zooplankton diversity and functioning along a natural stress gradient: when the going gets 677 tough, the tough get going[END_REF].

93

Major consumers of primary production, detrital organic matter or bacterial production according to 94 environmental conditions, copepods are an intermediate link within the pelagic food web and provide 95 the main pathway for energy from lower to higher trophic levels (e.g. fish, marine mammals; [START_REF] Richardson | In hot water: zooplankton and climate change[END_REF]. By acting on the mean residence time of particulate organic matter in surface waters 97 and on the sinking flux of particulate organic carbon, they significantly contribute to the biological 98 carbon pump [START_REF] Beaugrand | Marine biodiversity, ecosystem functioning, and 578 carbon cycles[END_REF]. Highly sensitive to changes in environmental conditions, 99 copepods also rapidly integrate environmental signals over generation time and transfer potential 100 changes to the next generation [START_REF] Goberville | Synchronous response of marine plankton 662 ecosystems to climate in the Northeast Atlantic and the North Sea[END_REF].

96

101

Changes in copepod abundances, diversity and community structure can have rapid and major 102 consequences on higher trophic level species. For example, previous studies have paralleled changes in 103 the abundance of Calanus finmarchicus or Pseudocalanus spp and alterations in commercially exploited 104 fish stocks such as Atlantic cod Gadus morhua, Atlantic salmon Salmo salar and Atlantic herring Clupea 105 harengus [START_REF] Cushing | The gadoid outburst in the North Sea[END_REF][START_REF] Beaugrand | Relationships between North Atlantic salmon, plankton, and 585 hydroclimatic change in the Northeast Atlantic[END_REF][START_REF] Johnson | Indicators of pelagic habitat status in the northwest Atlantic[END_REF]. Biogeographical shifts in 106 calanoid copepods in the northeast Atlantic have been related to changes in water masses and 107 atmospheric forcing [START_REF] Beaugrand | Unanticipated biological changes and global warming[END_REF]. In a Mediterranean coastal bay, taxonomic diversity indices 108 (e.g. Simpson's index, Pielou's evenness) have been computed from zooplankton species to determine 109 the effects of anthropogenic impacts [START_REF] Bandeira | Mathematical convergences of biodiversity 568 indices[END_REF][START_REF] Serranito | Proposition of indicators of 779 anthropogenic pressure in the Bay of Toulon (Mediterranean Sea) based on zooplankton time-780 series[END_REF]. This list, far from 110 being exhaustive, sheds light on copepods as ideal candidates for tracking ecosystem changes 111 [START_REF] Richardson | In hot water: zooplankton and climate change[END_REF]. We selected two coastal systems located in the southeast of the Bay of Biscay along the French 127 coast (Fig. 1) to examine year-to-year changes in copepod abundances and diversity. 131

The Eyrac site (44°40'N, 1°10'W; Fig. 1) is situated in the median neritic waters (salinity: 26.8-132 33.2; [START_REF] Vincent | Effects of a brief climatic event on zooplankton community 791 structure and distribution in Arcachon Bay (France)[END_REF] of the Arcachon Bay, a temperate mesotidal ecosystem highly influenced by 133 tides and winds [START_REF] Plus | Hydrodynamic characterization of the Arcachon 747 Bay, using model-derived descriptors[END_REF] [START_REF] Plus | Hydrodynamic characterization of the Arcachon 747 Bay, using model-derived descriptors[END_REF]. The zooplankton community is described as diverse (Sautour 140 and Castel, 1993), with eurytopic continental and neritic, and autochthonous species, associated to 141 polyhaline water masses (due to low freshwater inputs, typical estuarine species are confined to the inner 142 eastern part of the Bay; [START_REF] Vincent | Effects of a brief climatic event on zooplankton community 791 structure and distribution in Arcachon Bay (France)[END_REF].

143

The Gironde downstream site (45°31'N, 0°57'W; Fig. 1) is representative of the polyhaline zone 144 of the Gironde estuary (salinity > 30; [START_REF] Chaalali | the rise in E. affinis and A. bifilosa may have been favoured by punctual 499 inputs of freshwater[END_REF], which is one of the most turbid and largest 145 macrotidal estuary of Europe. Its large mouth allows important exchanges with the Bay of Biscay (tidal 146 prism: 1.1 to 2.0 billion cubic metres; [START_REF] Jouanneau | The Gironde Estuary[END_REF] and no autochthonous 147 zooplankton species can develop in polyhaline water masses (excepting meroplankton organisms whose 148 adults inhabit the estuary). Important freshwater inputs from the Garonne and Dordogne rivers (647 m 3 149 s -1 and 342 m 3 s -1 , respectively) act on the growth of estuarine species in oligo-and mesohaline water 150 masses. In this naturally stressed environment [START_REF] Dauvin | Benthic indicators and index approaches in the three main estuaries along the French 628 Atlantic coast (Seine, Loire and Gironde)[END_REF], an increasing gradient of 151 zooplankton diversity is observed from the upstream to the downstream areas [START_REF] Sautour | Comparative spring distribution of zooplankton in three macrotidal 775 European estuaries[END_REF]152 Chaalali et al., 2013a). established before conducting the surveys, so that sampling is carried out at a monthly scale in both 159 sites, at high tide and in the top first two meters below the surface using horizontal tow and a standard 160 200µm WP2 net [START_REF] Fraser | Standardization of zooplankton sampling methods at sea[END_REF]. The volume of water filtered through the net was recorded with a 161 Hydrobios digital flowmeter and samples were fixed in 5% seawater/buffered formalin.

162

In the laboratory, samples were sorted and copepods were counted and identified to the species 163 level as far as possible. Identification was carried out with a stereomicroscope Zeiss Axiovert (200 and 164 400) and following [START_REF] Rose | Copépodes pélagiques[END_REF], the World Register of Marine Species database (WoRMS; 165 www.marinespecies.org) and the taxonomic classification provided by Razouls et al. (2005[START_REF] Razouls | Diversity and Geographic 753 Distribution of Marine Planktonic Copepods[END_REF]. Because rare species may reflect stochastic sampling effects [START_REF] Poos | Addressing the removal of rare species in multivariate bioassessments: 749 The impact of methodological choices[END_REF] and 167 decrease the signal-to-noise ratio [START_REF] Borcard | Numerical Ecology with R[END_REF] only species with a presence >5% over the period 168 1998-2014 were retained (Table S1). This procedure, similar to the approach applied in Ibanez and 169 Dauvin (1988), allowed the selection of 17 species in each site, with 13 species being common to both 170 ecosystems (Table 1 andTable S1). For each site, copepod abundances were averaged per year to 171 remove the effect of seasonality prior to further analysis. 2.4. Analysis 1: Year-to-year changes in coastal copepod abundances (see Fig. S1)

185
Since species abundance data exhibited skewed distributions, data were transformed using the 186 log10(x + 1) function (Fig. S2; [START_REF] Jolliffe | Principal component analysis[END_REF]. A simple moving average of order-1 was applied to 187 reduce the noise inherent to these data; we therefore highlighted long-term variability while minimising 188 the influence of short-term fluctuations [START_REF] Legendre | Numerical Ecology[END_REF].

189

To characterise year-to-year changes in coastal copepod abundances, standardised Principal

248

To characterise the main year-to-year changes that took place in physical, chemical and 249 hydrological conditions at each site, we followed the same procedure than that applied to identify

250

Year-to-year changes in taxonomic diversity of coastal copepods 299

The 13 diversity indices were calculated and represented by a contour diagram, their trends being 300 ordered to emphasise common patterns of variability in α and β-diversity (Fig. 3). For each site, a 301 standardised PCA was performed on indices to (1) determine groups of diversity measures (Loiseau et 302 al., 2016) and ( 2) characterise year-to-year changes in taxonomic diversity (Fig. 4, Table 2 andFig [START_REF] Ives | Stability and diversity of ecosystems[END_REF]. Year-to-year changes in the PC2 (13.1% of the total variability; Fig. 4b) were 328 mainly explained by β-diversity indices (Table 2). 329 3.2.2. The Gironde downstream site 330 At the Gironde downstream, the patterns of diversity also showed differences between trends in 331 α and β-diversities (Fig. 3b), a result supported by results from the PCA (Fig. 4c-d, Table 2 andFig For each site, the principal components that derived from the PCAs performed on copepod 353 abundances were represented in a plane (Fig. 5). For each observation (i.e. annual changes in 354 abundances; Analysis 1), we attributed the value corresponding to the first PC of the PCAs performed 355 on diversity indices (Analysis 2). Given the high percentage of explained variance, we only considered 356 the PC1 of the PCA on diversity indices (74.1% and 60.9% of the total variability; see Fig. 4a,c). After 357 interpolation in the plane, these values were represented by a colour scale to graphically represent the 358 relationships between changes in copepod abundances and taxonomic diversity.

Eyrac

Gironde downstream Indices

359

At the Eyrac site, the highest anomalies in abundances observed prior 2006 coincided with 360 positive values of changes in diversity (Fig. 5a). After a period of relative stability between 2006 and 361 2010 (i.e. no high anomaly was detected), negative anomalies in the first two PCs were related to strong 362 negative changes in diversity (Fig. 5a). At the Gironde downstream site, the negative anomalies of the PC2 (1998PC2 ( -2002) ) were mainly linked to high negative values of changes in diversity (with the exception

363

376

To estimate a possible influence of changes in environmental conditions, we first performed a 377 PCA on physical, chemical and hydrological variables, for each site (Fig. 6 and Table 3). Year-to-year 378 changes in PC1 at the Eyrac site (46.3% of the total variability; Fig. 6a) showed high values of the S3) indicated a rise in oxygen, chlorophyll a and total 383 nitrogen that paralleled a reduction in river discharge, particulate matter (SPM and POC) that took place anomalies. The largest contributions to this change revealed that the reduction in freshwater inputs at 390 the Gironde estuary coincided with an increase in salinity and a decline in particulate matter (Table S3).

391

Year-to-year changes in PC2 (22.2% of the total variability; Fig. 6d) showed a pseudo-cyclical 392 variability of ~4 years with temperature and total nitrogen that predominantly contributed to the 393 component. S3).

- ------------------Environment ------------------ Species abundances PC1 0.761 0.080 0.346 0.501 0.691 0.128 0.053 0.900 (Fig. 2) PC2 -0.010 0.981 -0.666 0.071 -0.479 0.337 0.444 0.270 PC3

--------0.321 0.535 0.425 0.294 Taxonomic diversity PC1 0.781 0.038 -0.111 0.812 -0.719 0.172 -0.125 0.789 (Fig. 4) PC2 -0.018 0.955 0.563 0.057 -0.260 0.468 0.402 0.250 400 Table 3. Correlations between the first two principal components (PCs) of the principal component 401 analyses (PCAs) performed on environmental parameters and the first PCs of the PCA performed on 402 copepod abundances and taxonomic diversity. Probability were corrected to account for temporal 403 autocorrelation with the method recommended by [START_REF] Pyper | Comparison of methods to account for autocorrelation analyses of 751 fish data[END_REF]. Significant correlations (r 404 > |0.5|) are in bold.

405

Results from correlation analysis highlighted patent relationships between modifications in the 406 water column properties (as inferred from the PCAs performed on environmental parameters) and 407 changes in copepod abundances and taxonomic diversity (Table 3). Considering interpretations of the 408 PCAs (Figs. 2,4,6 and Fig S4), we revealed that the increase in salinity, total nitrogen, chlorophyll a 409 and oxygen at the Eyrac site, as well as the decrease in river discharge and particulate matter, were 410 positively related to a decline in α and ß-diversity (r=0.781, p=0.04 between PCs1, r=0.563, p=0.06 between PCs2; Table 3). This decline in diversity metric was consecutive to a shift towards dominance 412 of E. acutifrons, Oithona spp. and Oncaea spp., and a reduction in the abundance of most other species 413 as showed by the high correlations we calculated with the PCs of the PCA performed on copepod 414 abundances (r=0.761, p=0.08 between PCs1, r=-0.666, p=0.07 between PCs2). At the Gironde 415 downstream site, the relations we found involve only the first PCs obtained from the different PCAs

416

(Table 3). The decrease in both river discharge and particulate matter, and the concomitant rise in salinity 417 were highly positively related (r=0.691, p=0.13) to the increasing abundance of species such as T.

418 stylifera and A. clausi. This coincided with an increase in α-diversity, as displayed by the correlation 419 between the environment and diversity (r=-0.719, p=0.17). [START_REF] Richardson | Plankton and Climate[END_REF][START_REF] Goberville | Synchronous response of marine plankton 662 ecosystems to climate in the Northeast Atlantic and the North Sea[END_REF]. Drifters by definition, zooplankton 425 species are associated to different water masses [START_REF] Richardson | Plankton and Climate[END_REF] and changes in assemblages in an 426 area are often linked to advective processes, such as water exchanges between neighbouring regions 427 [START_REF] Willis | The influence of advection 795 on zooplankton community composition in an Arctic fjord (Kongsfjorden, Svalbard)[END_REF]. Monitoring zooplankton as indicators of changes offers therefore undeniable 428 advantages and estimating species diversity is relevant to examine how climate variability, hydrographic 429 conditions and/or anthropogenic activities influence ecosystem status (e.g. Beaugrand and Edwards, 430 2001;[START_REF] Serranito | Proposition of indicators of 779 anthropogenic pressure in the Bay of Toulon (Mediterranean Sea) based on zooplankton time-780 series[END_REF]. However, the way in which species diversity is measured can sometimes 431 lead to contradictory results [START_REF] Mcgill | Fifteen forms of biodiversity trend in 723 the Anthropocene[END_REF], especially when analyses ignore ecological context 432 [START_REF] Elahi | Recent 645 trends in local-scale marine biodiversity reflect community structure and human impacts[END_REF]. In addition, the selection of the appropriate diversity indices remains challenging in 433 littoral ecosystems because of the naturally high variability in zooplankton community composition, 434 assemblages being the result of a continuous mixing between continental, neritic and autochthonous 435 species, when water masses residence time is long enough [START_REF] Sautour | Distribution of zooplankton populations in Marennes-Oléron Bay (France), 773 structure and grazing impact of copepod communities[END_REF]. Each species 463 severe seagrass decline, concomitant with an increase in phytoplankton and macroalgae production, was 464 observed between 2005 and 2007 [START_REF] Plus | Phytoplankton 744 versus macrophyte contribution to primary production and biogeochemical cycles of a coastal 745 mesotidal system. A modelling approach[END_REF]. For the first time in 2005, Brown Muscle Disease 465 emerged in the Arcachon Bay, leading to a steady decline of Asari clam stocks in the years that followed 466 (de [START_REF] De Montaudouin | Why is Asari (=Manila) clam Ruditapes philippinarum fitness poor in Arcachon Bay: 641 A meta-analysis to answer?[END_REF]. This mid-2000s event also coincides with what have been found in other 467 littoral zones of Western Europe [START_REF] O'brien | ICES Phytoplankton and Microbial Plankton Status 732 Report 2009/2010[END_REF][START_REF] Lefebvre | Long-term hydrological and phytoplankton 700 monitoring (1992-2007) of three potentially eutrophic systems in the eastern English Channel 701 and the Southern Bight of the North Sea[END_REF] and is likely to have been

468

triggered by the extremely cold and dry winter of 2005 in southwestern Europe and its consequences on 469 the upper ocean hydrographic structure of the Bay of Biscay [START_REF] Somavilla | Large 782 changes in the hydrographic structure of the Bay of Biscay after the extreme mixing of winter 783 2005[END_REF]. We caution 470 however that not all species reacted at the same time and with the same magnitude in both sites. Such a 471 situation has been already depicted in the North Sea where only 40% of plankton species exhibited an 472 abrupt shift in the late 1980s [START_REF] Beaugrand | Detecting plankton shifts in the North Sea: a new abrupt 581 ecosystem shift between 1996 and 2003[END_REF], this fraction being mainly characterised by species 473 located at the edge of their distributional range, and therefore more sensitive to subtle environmental 474 changes [START_REF] Beaugrand | Unanticipated biological changes and global warming[END_REF].

475

In a context of global spasm of biodiversity loss, an overall decrease in α-diversity is expected in 476 almost all ecosystems (e.g. [START_REF] Worm | Impacts of biodiversity loss on ocean ecosystem services[END_REF][START_REF] Ceballos | Accelerated 603 modern human-induced species losses: Entering the sixth mass extinction[END_REF]. However, our results substantiated 477 that trends in diversity are more intricate at finer spatial scales, and that they may be strongly influenced 478 by local ecological context [START_REF] Sax | Species diversity: from global decreases to local increases[END_REF][START_REF] Elahi | Recent 645 trends in local-scale marine biodiversity reflect community structure and human impacts[END_REF][START_REF] Mcgill | Fifteen forms of biodiversity trend in 723 the Anthropocene[END_REF]. At the Eyrac 479 site, and despite slight variations between indices, a patent reduction in α-diversity was observed since [START_REF] Salas | Evaluation of the applicability of a marine biotic 767 index to characterize the status of estuarine ecosystems: the case of Mondego estuary (Portugal)[END_REF].

488

In the Gironde downstream site, a patent increase in α-diversity -associated to a relative 489 equitability among five taxa -was detected since the mid-2000s: P. parvus, Oithona spp. and E.

517

the assessment of trends in diversity, however [START_REF] Morris | 729 Choosing and using diversity indices: insights for ecological applications from the German 730 Biodiversity Exploratories[END_REF][START_REF] Loiseau | Indices for assessing coral reef fish biodiversity: the need for a change 707 in habits[END_REF], 518 especially in littoral areas where strong environmental gradients and high variability of physico-519 chemical parameters take place [START_REF] Dauvin | Benthic indicators and index approaches in the three main estuaries along the French 628 Atlantic coast (Seine, Loire and Gironde)[END_REF][START_REF] Bouchet | Benthic foraminifera to assess Ecological Quality 592 Statuses in Italian transitional waters[END_REF]. Here, the use of a wide range 520 of indices strengthened our confidence in the characterisation of sudden changes in biodiversity as well 521 as the quantification of long-term trends; although we conceded that both functional and phylogenetic 522 diversity were not scrutinised due to data availability [START_REF] Loiseau | Assessing the multicomponent aspect of coral fish diversity: The impact of sampling unit 710 dimensions[END_REF]. In each site, diversity indices 523 performed similarly over the study period, not only because of the mathematical convergence between 524 some indices [START_REF] Bandeira | Mathematical convergences of biodiversity 568 indices[END_REF][START_REF] Morris | 729 Choosing and using diversity indices: insights for ecological applications from the German 730 Biodiversity Exploratories[END_REF], but also because of the significance of changes 525 in copepod species. This was supported by the multivariate approach performed on species abundances.

526

While diversity indices are straightforward to effectively summarise and communicate diversity trends, 527 our results highlighted that combination with multivariate approaches provide useful insights into 528 community changes (e.g. distinguishing 'winners' and 'losers' species; see [START_REF] Mcgill | Fifteen forms of biodiversity trend in 723 the Anthropocene[END_REF].

529

Information of why diversity fluctuates is essential for proper interpretation of changes but it is also 530 essential to recall that long-term biodiversity time-series only inform on species abundances and variety 531 at a given location and at a number of points in time [START_REF] Magurran | Long-term datasets in biodiversity research and monitoring: 719 assessing change in ecological communities through time[END_REF]. This was well summarised 532 by [START_REF] Magurran | Long-term datasets in biodiversity research and monitoring: 719 assessing change in ecological communities through time[END_REF] who wrote: "researchers cannot necessarily assume that responses to change 533 documented in long-term datasets will be universal, even where the same types of organisms are 534 involved".

535

Over the last few decades, many countries have mandated assessment of coastal water bodies 536 and classical diversity indices have been intensively used to characterise diversity patterns (Beaugrand 537 and Edwards, 2001;[START_REF] Magurran | Measuring biological diversity[END_REF], to detect anthropogenic pressures [START_REF] Serranito | Proposition of indicators of 779 anthropogenic pressure in the Bay of Toulon (Mediterranean Sea) based on zooplankton time-780 series[END_REF] or to 538 investigate ecosystem level consequences of diversity changes [START_REF] Gagic | 659 Functional identity and diversity of animals predict ecosystem functioning better than species-660 based indices[END_REF]

  28

Figure 1 .

 1 Map of the Gironde Estuary and Arcachon Bay showing the two studied sites: the Eyrac site 130 and the Gironde downstream site.

  collected at the two fixed sampling sites (Fig. 1), from 1998 to 2014 by the 155 SOGIR survey ('Service d'Observation de la GIRonde') at the Gironde downstream site (average depth 156 at high tide = 8.2m) and from 2001 to 2014 by the SOARC survey ('Service d'Observation du bassin 157 d'ARCachon') at the Eyrac site (average depth at high tide = 8m). A standardised protocol has been 158

  -chemical properties of coastal waters at the Eyrac and the Gironde 174 downstream sites were estimated using data from the 'Service d'Observation en Milieu LITtoral' 175 (SOMLIT; somlit.epoc.u-bordeaux1.fr) collected on a bi-monthly basis at sub-surface and high tide (see 176 Goberville et al., 2010 for further details). Here, we focused on seven parameters: temperature, salinity, 177 oxygen, total nitrogen (TN) concentration (computed by summing nitrate, nitrite and ammonium 178 concentrations), particulate organic carbon (POC), suspended particulate matter (SPM) and chlorophyll 179 a. Note that species samples (from the SOGIR and SOARC surveys) and environmental parameters 180 (from the SOMLIT programme) were sampled simultaneously. In addition, we included data on mean 181 river discharges recorded (i) near the Leyre River mouth for the Eyrac site and (ii) in the downstream 182 part of the Gironde estuary (http://www.hydro.eaufrance.fr/, Ministère de l'Ecologie et du 183 Développement Durable).

  184

190

  Component Analyses (PCAs) were performed separately on correlation matrices during the period 2001-243 (Eyrac site, Fig. 5a) and 1998-2014 (Gironde downstream site, Fig. 5b-c), the value of changes in 244 taxonomic diversity (i.e. results from the PCA performed on indices) was assigned and represented by 245 a colour scale; the blue (red) gradient corresponds to high negative (positive) values. By characterising 246 each year by reference to changes in copepod diversity, this representation showed time series of 247 responses of each site, i.e. changes in copepod communities over the time period.

289 Figure 2 .

 2892 280of the total variability) mainly expressed positive anomalies from 2003 (Fig.2d). Acartia tonsa was the 281 only species strongly negatively correlated with this change, revealing a constant decline. Species such 282 as Oithona spp., E. acutifrons or C. typicus were positively related to PC2, corresponding to an increase 283 in abundance over the last decade. Year-to-year changes in the third PC (19.6% of the total variability) 284 displayed pronounced positive values from 2001 to 2005, at the time the component showed negative 285 anomalies (2006-2013). A. discaudata and Acartia bifilosa were positively related to PC3, denoting 286 decreasing abundances from the mid-2000s, while D. anglicus increased. For the period 2001-2014, this 287 third PC revealed strong similarities with the PC1 observed at the Eyrac site (Fig. 2a versus Fig. 2e). 288 Year-to-year changes in pelagic copepod abundances in the two coastal systems calculated 290 from a standardised principal component analysis (PCA). (a-b) First two principal components (PCs) 291 calculated from the standardised PCA performed on copepod abundances in Eyrac. (c-e) First three 292 principal components (PCs) computed from the standardised PCA applied on copepod abundances in 293 the Gironde downstream site.

Figure 3 .

 3 Diversity indices calculated for pelagic copepod species in (a) Eyrac (2001-2014) and (b) 306 Gironde downstream (1998-2014). SpR: Species Richness, Marg: Margalef indice, Menh: Menhinick 307 indice, Odum: Odum indice, BerPer: Berger-Parker indice, McIn: McIntosh indice, Simp: Simpson 308 indice, Shan: Shannon indice, Piel: Pielou's eveness derived from Shannon indice, Jturn: turnover 309 component of Jaccard indice, Jnest: nestedness component of Jaccard indice, Jacc: Jaccard indice, Jbeta: 310 beta ratio. For visual comparison indices were normalised between 0 and 1. White areas correspond to 311 missing values. 312 3.2.1. The Eyrac site 313 The general patterns of copepod diversity at the Eyrac site (Fig. 3a) and results from the PCA 314 based on indices (Fig. 4a-b,

Figure 4 .

 4 Alpha-diversity measures, which were related to the first PC of the PCA on indices (60.9% of the 333 total variability; Fig. 4c), exhibited inverse patterns of variation when compared to Eyrac: low values 334 were observed until the mid-2000s, followed by a strong increase until 2011 and a progressive decrease 335 from 2012. This reduction in α-diversity is especially visible for metrics based on the number of species 336 (e.g. Menhinick indice). Year-to-year changes in β-diversity indices were mainly associated to the 337 second principal component (18.8% of the total variability; Fig. 4d) and showed an increase in β-338 diversity during the periods 2001-2007 and 2011-2014. In contrast to 2007-2010, a higher variability in 339 species assemblages was observed during this period. While the trend in β-diversity from 2001 to 2007 340 coincided with a rise in α-diversity -and therefore species gain (e.g. T. stylifera, D. anglicus) -increasing 341 β-diversity from 2011 was related to a decrease in α-diversity (i.e. species loss). 342 343 Year-to-year changes in coastal copepod taxonomic diversity in the two coastal systems. (a) 344 First and (b) second principal components (PCs) calculated from the standardised PCA performed on 345 diversity indices in Eyrac. (c) First and (d) second principal components (PCs) calculated from the 346 standardised PCA performed on diversity indices in the Gironde downstream site.

Figure 5 .

 5 364 of 2008; Fig. 5b), and vice versa. The same contrasting -but more pronounced -pattern emerged with 365 the positive values of the PC3: the period prior 2005 was mainly related to negative changes in diversity 366 (Fig. 5c). A clear modification in copepod communities (for both species abundances and diversity) took 367 place in the mid-2000s in the two sites. 368 369 Relationships between changes in coastal copepod diversity and changes in coastal 370 copepod abundances for the Eyrac site (left panel) and the Gironde downstream site (right panels) (a) 371 Relationships between changes in diversity (first PC of the PCA performed on taxonomic diversity 372 indices) and the first two PCs of the PCA performed on coastal copepod abundances at the Eyrac site. 373 (b-c) Relationships between changes in diversity and the first and (b) second or (c) third PC from the 374 PCA performed on coastal copepod abundances at the Gironde downstream site. The values of changes 375 in measures of diversity were interpolated and represented by the colour scale (see Analysis 3).

379

  component from 2001 to 2003, which then plateaued and shifted down from 2012. The second PC 380 (26.6% of the total variability; Fig. 6b) exhibited a marked decrease from 2001 to the mid-2000s, 381 followed by negative pseudo-cyclical values and two years of positive anomalies in recent years. The 382 examination of the first two eigenvectors (Table

384

  from 2001 to the mid-2000s. When considering the two first PCs (Fig S4e), a clear opposite pattern of 385 changes was detected between salinity and river discharge, indicating that the decrease in freshwater 386 from the Leyre River mainly correlated with an increase in salinity. The first PC of the PCA performed 387 at the Gironde downstream site (50.7% of the total variability; Fig. 6c) exhibited a strong decrease from 388 1998 to the mid-2000s, followed by a period of negative (2004-2012) and positive (2013-2014) 389

394 395Figure 6 .

 3946 Year-to-year changes in environmental conditions in the two coastal systems. (a) First 396 and (b) second principal components (PCs) calculated from the standardised PCA performed on 397 environmental parameters in Eyrac. (c) First and (d) second principal components (PCs) calculated from 398 the standardised PCA performed on environmental parameters in the Gironde downstream site (see 399 Table

  are highly sensitive to environmental changes, rapidly reproducing 422 organisms with wide dispersal ability according to hydrodynamic processes, and as they integrate and 423 transfer environmental signals over generation time, species assemblages are known to mirror 424 ecosystems conditions

  112Here, by using data from zooplankton surveys from 1998 to 2014, we examine year-to-year 113 changes in copepod communities (species abundances and taxonomic diversity) in two nearby littoral 114 areas of Western Europe (i.e. the Arcachon Bay and the Gironde estuary) that share similar climate

	115	conditions but contrasting physical, chemical and hydrological environments. The following questions
	116	are addressed: Do copepod communities differ between the two sites and change over time? Are trends
	117	in taxonomic diversity apparent and linked to environmental changes? To study changes in species
	118	abundances and diversity that took place in the Arcachon Bay and the Gironde estuary over the last two
	119	decades, we combine a principal component analyses based-approach and commonly used taxonomic
	120	diversity indices that account for the number of species (e.g. species richness), the evenness of
	121	abundance distribution among species (e.

g. Pielou index) and the variability in communities among 122 years (e.g. Jaccard index). We then investigate divergences between these two adjacent sites and explore 123 the possible mechanisms that explain diversity trends and species responses to environmental changes. 124 2. Materials and methods 125 2.1. Sampling sites 126

  . The Arcachon Bay is open to the Bay of Biscay through two narrow

	134	channels (4-5m depth) separated by several sandbanks. This distinctive narrow entrance has important
	135	effects on the water mass exchange between the Bay and the Atlantic Ocean: the tidal prism is equal to
	136	384 million of cubic meters, 64% of the lagoon total volume being flushed in and out at each tidal cycle
	137	(Plus et al., 2009). Neritic water masses within the Bay are influenced mainly by freshwater inputs from
	138	the Leyre river (20 m 3 s -1 ). The Arcachon Bay is therefore quite confined and water residence time is
	139	approximately 20 days

  268and 2012-2014) and positive(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011) anomalies (Fig.2b). The study of the second eigenvector 269 revealed that an increase in the abundance of Acartia discaudata and Parapontella brevicornis, and to 270 a lesser extent Centropages typicus, occurred between 2003 and 2011, while a reduction in the 271 abundance of Calanus helgolandicus and Oncaea spp. was observed. Inspection of the first eigenvector indicated that Oncaea spp., C. helgolandicus and,

	272	3.1.2. The Gironde downstream site
	273	The first PC of the PCA performed on copepods at the Gironde downstream site (28.6% of the
	274	total variability) showed periods of positive (1998-2003 and 2012-2014) and negative (2003-2011)
	275 anomalies (Fig. 2c). 276
	257	3. Results
	258	3.1. Year-to-year changes in coastal copepod abundances
	259	3.1.1. The Eyrac site
	260	Year-to-year changes in PC1 of the PCA performed on copepod abundances at the Eyrac site
	261	(57.7% of the total variability) showed high values of the component from 2001 to 2005, followed by a
	262	decrease in the trend and negative values from 2006 onwards (Fig. 2a). Examination of the first
	263	eigenvector indicated that species such as Isias clavipes, Paracalanus parvus and Ditrichocorycaeus
	264	anglicus were positively correlated with the component, corresponding to a decrease in their abundance

changes in copepod abundances and diversity (see 2.4 and 2.5): (1) a one-year moving average on annual 251 means, (2) a Procrustes test and (3) a PCA performed on logged data. Pearson correlation analyses 252 (Table 3) were then performed between the first PCs obtained from Analysis 1 and 2 and the first two 253 PCs calculated from the PCA applied on environmental parameters at each site. Following the procedure 254 recommended by Pyper & Peterman (1998), probabilities were computed and corrected to account for 255 temporal autocorrelation: Box and Jenkins' (1976) autocorrelation function modified by Chatfield was 256 calculated and applied to adjust the degree of freedom using Chelton's (1984) formula. 265 from the mid-2000s onwards (Table 1, Fig. S4a). Oithona spp. and Euterpina acutifrons were strongly 266 negatively related to changes in the first PC, showing an increase in their abundance from 2006 to 2014. 267 The second principal component (19% of the total variability) exhibited periods of negative (2001-2002 to a lesser extent, Pseudodiaptomus marinus and Eurytemora affinis were positively related to PC1, 277 corresponding to a reduction in their abundance between 2003 and 2011 (Table 1, Fig. S4b). In contrast, 278 the abundance of Temora stylifera, Centropages hamatus, Pseudocalanus elongatus and Acartia clausi 279 increased. After a period of strong negative anomalies

(1998)(1999)(2000)(2001)(2002)(2003)

, year-to-year changes in PC2 (25.9%

Table 1 .

 1 Results from the standardised PCAs performed on copepod abundances. The first two 296 eigenvectors (for Eyrac) and the first three eigenvectors (for Gironde downstream) are included and 297 show the contribution of each species to the principal components. Values in bold were superior to |5.88|.

	Acartia bifilosa	--	--	5.22	-3.81	13.15
	Acartia clausi	4.85	-2.87	-7.25	0.68	-0.11
	Acartia discaudata	-0.04 26.49	-0.03	1.7	20.96
	Acartia tonsa	--	--	-1.55	-12.56	2.91
	Calanus helgolandicus	0.94 -13.07 11.49	-0.08	0.27
	Centropages hamatus	5.76	-4.15	-9.37	9.31	0.75
	Centropages typicus	3.12	6.66	4.58	13.42	-0.32
	Clausocalanus sp	8.27	1.81	--	--	--
	Cyclopinoïdes littoralis	7.66	-4.52	--	--	--
	Ditrichocorycaeus anglicus	8.27	2.03	0.19	0	-20.76
	Eurytemora affinis	--	--	8.11	-0.66	10.36
	Euterpina acutifrons	-7.47	0.1	-0.85	14.25	8.59
	Isias clavipes	9.07	-0.13	--	--	--
	Oithona sp	-9.42	0.46	1.42	16.15	-0.1
	Oncaea sp	-2.09 -18.01	16	0.51	0.01
	Paracalanus parvus	8.59	-0.21	-0.92	9.82	4.46
	Parapontella brevicornis	4.32	14.4	--	--	--
	Pseudocalanus elongatus	7.62	2.04	-9.31	-0.68	7.62
	Pseudodiaptomus marinus	--	--	8.82	8.93	-3.51
	Temora longicornis	5.55	1.12	-2.17	7.29	0.6
	Temora stylifera	6.96	1.92	-12.73	0.14	-5.51
	295
	298

Table 2 and

 2 Fig.S4c) revealed a clear contrast between α and β-diversity 315 measures, leading to two groups. The first group encompassed α-diversity indices that mostly

	316	contributed to the PC1 (74.1% of the total variability; Fig. 4a, Table 2). The highest values of the
	317	component (2001-2006), were followed by a period of low values until 2011. Only a slight difference
	318	in the timing of changes was observed between indices based on the number of species (e.g. species
	319	richness) and evenness and heterogeneous indices such as Pielou and Simpson indices (Fig. 3a). Low α-
	320	diversity, detected from 2011, corresponded to a loss of species, probably related to a decrease in typical
	321	coastal species such as I. clavipes and C. helgolandicus; copepod assemblages became dominated by

322

three taxa: E. acutifrons, Oithona spp. and Oncaea spp. (Fig.

S2

). The second group, which gathered 323 together β-diversity indices (i.e. the Jaccard's dissimilarity index and its components), showed low 324 values until 2011-2012 that suggested weak alterations in species assemblages during this period. From 325 2011, the marked increase in β-diversity trend revealed a high variability in assemblages in relation to a 326 loss of species, probably because a perturbation in community structure took place at the Eyrac site (Ives 327 &

Table 2 .

 2 Results from the standardised PCAs performed on taxonomic diversity for each site. The first 348 two eigenvectors show the contribution of each index to the principal components. Values in bold were

		PC1	PC2	PC1	PC2
	Species richness	8.8	-0.65	6.31	1.28
	Margalef	9.22	-0.8	10.81	-1.62
	Menhinick	5.83	-0.37	8.72	-4.21
	Odum	9.19	-0.81	10.77	-1.78

  . In the minds of 539 many, the unprecedented pace of global changes necessarily induced negative diversity trends, at any 540 spatial scale. This led policymakers to put emphasis on the need to mitigate diversity loss from local to 541 global levels (McGill et al., 2015) while disregarding possible positive diversity trends (Sax and Gaines, 542 2003). However, we showed here that opposite signals may emerge between nearby sites owing to local 543 ecological conditions (e.g. anthropogenic impacts, initial richness, species dominance; Elahi et al.,

	Eyrac abundance Relative Presence Eyrac Gironde downstream Gironde downstream Relative abundance Presence (in %) (in %) (in %) (in %) ----11.63 65.4 5.26 43.5 2.81 46.2 4.08 54 0.14 9.2 PC1 (tot.) Acartia bifilosa Species Acartia clausi Acartia discaudata PC2 (tot.) PC1 (tot.) PC2 (tot.) Number of PC3 (tot.) vs vs vs vs months used vs PCs1 (999 perm.) PCs2 (999 perm.) PCs1 (999 perm.) PCs2 (999 perm.) PCs3 (999 to calculate Eyrac Gironde downstream annual means perm.) rho rho rho rho rho Environmental parameter PC1 PC2 PC1 PC2
	Acartia tonsa Alteutha interrupta 10 1 Temperature Salinity Calanus helgolandicus Centropages hamatus 9 0.973 Oxygen Particulate Organic Carbon Centropages typicus Clausocalanus sp 8 0.958 Suspended Particulate Matter Chlorophyll a Cyclopinoïdes littoralis Diaixis spp 7 0.939 Total Nitrogen River discharge	-----8.79 1 -15.31 0.15 0.55 0.893 -18.04 -0.51 0.39 0.49 0.818 -11.38 -18.14 0.63 --0.756 -23.48 -4.34	----0.79 1 8.98 9.7 37.9 0.750 1.11 31.91 15.3 19.4 0.639 25.11 1.44 15.3 --0.592 3.20 27.45	14.73 0.01 1 2.04 15.95 0.19 4.75 0.665 11.83 13.22 0.25 --0.529 19.55 10.24 --<0.01 0.482 9.64 17.53	35.4 28.35 1 12.62 2.3 31.5 0.15 0.836 11.77 49.2 20.8 5.72 0.733 9.50 ----1.5 27.56 0.644 4.33
	Ditrichocorycaeus anglicus 6 0.917	0.56 0.676	43.5 0.551	0.19 0.426	40.8 0.542
	Pseudocalanus elongatus	0.48	21	1.06	41.5
	Eurytemora affinis	--	--	15.77	43.8
	Euterpina acutifrons	41.53	98.4	17.67	83.8
	Goniopsyllus rostratus	--	--	<0.01	1.5
	Isias clavipes	0.67	17.7	--	--
	Labidocera wollastoni	--	--	0.01	2.3
	Oithona spp	10.07	92.7	1.11	41.5
	Oncaea spp	4.66	69.4	0.51	45.4
	Paracalanus parvus	17.03	95.2	18.96	93.1
	Paracartia grani	0.14	4.8	--	--
	Parapontella brevicornis	3.04	68.5	0.02	4.6
	Pseudodiaptomus marinus	0.03	1.6	1.91	11.5
	Sapphirina spp	0.03	3.2	0.03	4.6
	Temora longicornis	7.74	62.9	7.80	48.5
	Temora stylifera	2.46	33.1	0.46	25.4
		Supplementary Table S1 Supplementary Table S2
		Richirt et al. Richirt et al.

Acknowledgements 558 We thank the National Institute for the Science of the Universe (CNRS) and the colleagues 559 associated to SOGIR-SOARC-SOMLIT -technicians, researchers, captains and crews -who have 560 contributed to the collection of the zooplankton samples. This work was part of the regional research 561 project INDICOP 2014-10464 (Région Nord -Pas-de-Calais).

562

The following supplement accompanies the article

Local changes in copepod composition and diversity in two coastal systems of Western Europe

Julien Richirt 1,2* , Eric Goberville 3* , Vania Ruiz-Gonzalez 1 and Benoît Sautour ) and (f) the Gironde downstream site (axis 1: 50.7%, axis 2: 22.2%). See Figure 3 for the meaning of indices. S1. Total relative abundance and presence (in percentage) of copepod species sampled at the Eyrac (from 2001 to 2014) and the Gironde downstream sites (from 1998 to 2014). Species with percentages in bold have been retained for the PCA analyses (presence ˃ 5%). S2. Results from the sensitive analysis performed to account for changes in sampling effort. Spearman correlation coefficients between the first PCs (PCx(tot.)) retained to characterise year-to-year changes in coastal copepod abundances in both study areas (see Figure 2) and the PCs obtained from the PCA analyses performed on re-estimated annual copepod abundances (PCx(999 perm.)) with a decreasing number of months used in the calculation of annual means and following a bootstrap procedure (999 permutations). rho: Spearman correlation coefficient. PC(s): Principal Component(s). S3. Results from the standardised PCAs performed on environmental parameters. The first two eigenvectors are included and show the contribution of each parameter to the principal components. Values in bold were superior to |12.50|.

Supplementary Table

Supplementary Table

Supplementary Table

Supplementary Figure S1

Richirt et al.

Supplementary Figure S2

Richirt et al.

Supplementary Figure S3

Richirt et al.

Supplementary Figure S4

Richirt et al. S3 Richirt et al.

Supplementary Table


P Cordesse

S Kokh

R Di Battista

F Drui

M Massot

Derivation of a two-phase flow model with two-scale kinematics, geometric variables and surface tension using variational calculus

The present paper proposes a two-phase flow model that is able to account for two-scale kinematics and two-scale surface tension effects based on geometric variables at small scale. At large scale, the flow and the full geometry of the interface may be retrieved thanks to the bulk variables, while at small scale the interface is accurately described by volume fraction, interfacial area density and mean curvature, called the geometric variables. Our work mainly relies on the Least Action Principle. The resulting system is an extension of a previous work modeling small scale pulsation in which surface tension was not taken into account at large or small scale. Whereas the original derivation assumes a cloud of monodispersed spherical bubbles, the present context allows for polydispersed, non-spherical bubbles. The resulting system of equations solely involves small scale geometric variables, thus contributing in the construction of a unified model describing both large and small scales.

Introduction

We consider, in this work, the simulation of two-phase flows involving potentially very different interface topologies in various areas of the flow. Such situations may occur in various industrial contexts including multiple stages, such as during the atomization of a liquid jet ranging from the deformation of the interface at the mouth of the injector, to the formation of a polydisperse spray of droplets downstream, through a mixed zone where the geometry of the interface may be complex.

The first step to pave the way to an unified Eulerian modeling of such complex flows was initiated in [START_REF] Drui | Small-scale kinematics of two-phase flows: identifying relaxation processes in separated-and disperse-phase flow models[END_REF] by making a first connection between models for separate phase flows and subscale modeling, aiming at also describing disperse flows such a bubbly flows. The starting ideas were to design a model that was able to account for two-scale kinematics and to close the model and identify small parameters in the case of bubbly flows, even if the final model was valid without any assumption on the structure of the subscale geometry of the interface. Our goal here is two-fold: first, we propose to include more geometrical information on the subscale description than in [START_REF] Drui | Small-scale kinematics of two-phase flows: identifying relaxation processes in separated-and disperse-phase flow models[END_REF], relying on the fact that this information allows the description of a cloud of droplets in [START_REF] Essadki | Adaptative Mesh Refinement and High Order Geometrical Moment Method for the Simulation of Polydisperse Evaporating Sprays[END_REF][START_REF] Essadki | Statistical modeling of the gas-liquid interface using geometrical variables: toward a unified description of the disperse and separated phase flows[END_REF] and second, we aim not only to account for two-scale kinematics but also for two-scale surface tension effects at both large scale and subscale. This paper is structured as follows. First we present a careful choice of the variables that shall describe the evolution of the system. More precisely, an argument similar to the Tube Formula of Weyl [START_REF] Weyl | On the Volume of Tubes[END_REF][START_REF] Gray | An Introduction to Weyl's Tube Formula[END_REF] will allow us to consider gas inclusions whose shape is diffeomorph to a sphere. This analysis will also allow us to draw connections between the density of interfacial area, the mean curvature and the volume fraction that will be considered as parameters of the flow. We will then design a Lagrangian energy that accounts for two-scale effects for both kinematics and capillarity effects. Finally we will use the Least Action Principle [START_REF] Serrin | Mathematical Principles of Classical Fluid Mechanics[END_REF][START_REF] Bedford | A variational theory of immiscible mixtures[END_REF][START_REF] Bedford | Hamilton's principle in continuum mechanics[END_REF][START_REF] Gavrilyuk | A variational principle for two-fluid models[END_REF][START_REF] Gavrilyuk | A new form of governing equations of fluids arising from Hamilton's principle[END_REF] that will provide us with a set of governing equations for our two-phase medium.

2 Description of the two-phase medium: two-scale structure

We consider two compressible materials k = 1, 2 that are both equipped with a barotropic equation of state (EOS) ρ k → f k , where f k and ρ k are respectively the specific free energy and the density of the fluid. The partial pressure p k and the sound velocity c k of the component k are defined by

p k = ρ 2 k df k /dρ k , c 2 k = dp k /dρ k .
We assume that there is a velocity equilibrium between both components and we note u as their common velocity. We assume our two-phase medium to be an immiscible mixture where, for each component, Y k and α k denote the mass and volume fractions respectively. If ρ is the density of the medium, we have

ρ = αρ 1 + (1 -α)ρ 2 , ρY k = α k ρ k , with α = α 1 = 1 -α 2 , Y = Y 1 = 1 -Y 2 .
We now need to describe the properties of the interface that separates both materials and distribute these properties over two different scales. let us first underline that we assume both scales to be always simultaneously present at each time-position (t, x). In our approach, we assume that the preponderant scale dominates the interface effects in the model (see Figure 1). Let us now detail the interface assumption we shall use for both scales.

large scale large & small scales small scale Fig. 1: Interface dynamics at large and small scales Concerning the large scale, we adopt a classic interface capturing approach (see for example [START_REF] Chanteperdrix | A compressible model for separated two-phase flows computations[END_REF]): we suppose that the interface position is captured within a narrow region where α rapidly varies from α 0 to α 1.

When the large scale is dominant, we postulate that the outward unit normal to the interface is accurately given by ∇α/|∇α| as originally done in [START_REF] Brackbill | A continuum method for modeling surface tension[END_REF].

When the small scale is predominant, we acknowledge that the properties of the interface are only available through the fields (t, x) → Σ and (t, x) → H that respectively provide a measure of the interfacial density area and the mean curvature in the vicinity of x at instant t. Let us now specify how these fields are related to the other variables of the flow. First, we assume that the topology of the small scale is consistent with a population of small gas inclusions whose shape is diffeomorph to a sphere in such way that we can apply Weyl's Tube Formula [START_REF] Weyl | On the Volume of Tubes[END_REF][START_REF] Gray | An Introduction to Weyl's Tube Formula[END_REF].

We now suppose that the shape of the bubbles whose position is x at instant t is altered by a small scale perturbation that is normal to their surface and with a (signed) length magnitude (oriented with respect to the outward unit normal) h(t, x) as depicted in Figure 2. In other words, (t, x) → h can be interpreted as a first-order estimate of the deformation length for the bubbles located in the vicinity of x at instant t. For such perturbations, the normal variation of the surface and the volume of the inclusions can be connected to the mean curvature and the surface of the inclusions as detailed in Appendix A. Consequently we postulate that the fields α, Σ, H, h are connected through the following relations:

dΣ dh = -2HΣ, dα dh = Σ. (1)
Hypotheses (1) express the fact that a reminiscence of relation ( 30) is valid for each small-scale gas inclusion through the fields α, Σ, H, h. In the sequel we make the strong assumption that (t, x) → H is given a priori and is not altered by the flow. This assumption can be lifted, but requires a more involved modeling at the subscale level.

We conclude this section by stating the following constraints on the flow

∂ρ ∂t + ∇ • (ρu) = 0, ∂ρY ∂t + ∇ • (ρY u) = 0, (2a)
D t Σ + 2HΣD t h = 0, D t α -ΣD t h = 0 (2b)
that respectively pertain to total mass conservation, partial mass conservation and the constrained evolution of α, Σ and h through the topological requirement (1).

Remark 1: The small scale perturbation encompasses purely normal variation of the inclusion interface. One could also account for volume stretching generated by a tangential variation of the normal as proposed in [START_REF] Lhuillier | Phenomenology of inertia effects in a dispersed solid-fluid mixture[END_REF]. However this situation is out of the scope of the present study since it requires an additional potential fluctuation of velocity at the subscale level, which we have not taken into account.

Two-scale Lagrangian energy

In order to derive a system of equations for our two-phase flow we exploit the Least Action Principle following [START_REF] Serrin | Mathematical Principles of Classical Fluid Mechanics[END_REF][START_REF] Bedford | A variational theory of immiscible mixtures[END_REF][START_REF] Bedford | Hamilton's principle in continuum mechanics[END_REF][START_REF] Gavrilyuk | A variational principle for two-fluid models[END_REF][START_REF] Gavrilyuk | A new form of governing equations of fluids arising from Hamilton's principle[END_REF]. The first step consists in providing the medium with a Lagrangian energy L. Following classic lines, we define L to be the difference between the kinetic energy and the potential energy of the system. In order to account for both large and small scale phenomena we will suppose that the kinetic energy of the system is defined by K small + K large where K small and K large refer respectively to the small scale and the large scale kinetic energy. In the same way, we assume that the potential energy of the system is

U bulk + U large int + U small int
where U bulk , denotes the bulk potential energy of the system, U large int and U small int are interfacial energies associated with large and small scale interface descriptions respectively.

The large scale kinetic energy is defined by setting

K large = 1 2 ρ|u| 2 . ( 3
)
We leverage the small scale variations of the inclusions h in order to define K small as follows

K small = 1 2 m(α, Σ)|D t h| 2 (4)
where

D t • = ∂ t • +u t ∇
• and m has the same dimensions as a density. The energy contribution (4) can be thought to be related to the virtual mass energy associated to the volume deformation of a gas inclusion at small scale. For the sake of simplicity we shall assume in the following sections that m is a constant.

We now turn to the definition of the potential energy of the system. We make the standard assumption that the bulk potential energy can be expressed as a bulk free energy as follows

U bulk = ρf (ρ, Y, α). (5)
For the large scale interface energy we postulate that

U large int = 1 2 σ|∇α| 2 , (6)
where σ > 0 is a coefficient pertaining to the large-scale capillarity. We define the interface energy associated with the small scale by

U small int = γΣ, (7)
where γ > 0 is a coefficient related to small scale capillarity. For the sake of simplicity we shall assume in the sequel that both σ and γ are constant.

Finally, the resulting Lagrangian L can be expressed as a function of ρ, Y , u, D t h, α, Σ and ∇α as follows

L(ρ, Y, u, D t h, α, Σ, ∇α) = ρ 2 |u| 2 + m(α, Σ) 2 |D t h| 2 -ρf (ρ, Y, α) - σ 2 |∇α| 2 -γΣ. (8)
Remark 2: It is important to emphasize that we do not provide here any mechanism for distributing the information carried by the variables of the system between small and large scales, which is crucial but out of the scope of the present work.

Extremization of the Action

We now follow classic lines of the Least Action Principle. Consider B(t) ⊂ R 3 the volume occupied by the fluid for t ∈ [t 0 , t 1 ]. Let X ∈ B(t 0 ) be the Lagrangian coordinates associated with the reference frame at instant t = t 0 , then we note (t, X) → ϕ L the position of the fluid particle whose position is X at t = t 0 . If (t, x) → b is any Eulerian field, it can be associated with the Lagrangian field (t, X) → b L by setting b(ϕ L (X, t), t) = b L (X, t). As h can be deduced from α and Σ by ( 2), then the flow can be fully characterized by (t, x) → (ρ, u, Y, α, Σ) or equivalently by x → (Y, α, Σ) and (t, X) → ϕ L if ϕ L complies with the mass conservation equation.

For a given transformation of the medium x → (Y, α, Σ) and (t, X) → ϕ L let (t, x, λ) → ( Y , α, Σ) and (t, X, λ) → ϕ L be a family of medium transformations parametrized by λ ∈ [0, 1]. We note Ω(λ) = (t, ϕ L (t, X, λ))|X ∈ B(t 0 ), t ∈ [t 0 , t 1 ] and we require these fields to satisfy constraints pertaining to mass conservation

∂ ρ ∂t + ∇ • ( ρ u) = 0, ∂ ρ Y ∂t + ∇ • ( ρ Y u) = 0, ( 9a
)
supplemented by constraints regarding the topology evolution

D t Σ = -2H Σ D t h, D t α = Σ D t h, (9b)
and finally classic boundary constraints

( Y , α, Σ)(t, x, λ = 0, 1) = (Y, α, Σ)(t, x), ϕ L (X, t, λ = 0, 1) = ϕ L (X, t), (10)
( Y , α, Σ)(t, x, λ) = g(Y, α, Σ)(t, x), (t, x) ∈ ∂ Ω(λ), (11)
ϕ L (X, t, λ) = ϕ L (X, t), (t, X) ∈ ∂([t 0 , t 1 ] × B(t 0 )). ( 12
)
Following standard lines, this family of transformation yields a family of infinitesimal transformations defined as follows

δ λ ϕ(t, ϕ L (t, X)) = ∂ϕ L ∂λ X,t (t, X, λ = 0), δ λ b(t, x) = ∂ b ∂λ t,x (t, x, λ = 0), ( 13
)
for b ∈ {ρ, Y, α, Σ, u}. Let us now define the Hamiltonian action A associated with Ω for the family of transformations (t, x, λ) → ( Y , α, Σ) and (t,

X, λ) → ϕ L A (λ) = Ω(λ) L( ρ, Y , u, D t h, α, Σ, ∇ α) dxdt. ( 14
)
The Least Action Principle states that a physical transformation of the system verifies dA dλ (0) = 0. (

Relation [START_REF] Cordesse | Supplementary conservative law for non-linear systems of PDEs with non-conservative terms: application to the modelling and analysis of complex fluid flows using computer algebra[END_REF] will provide the motion equations of the flow. In order to obtain a set of partial differential equations, we need to express dA /dλ . Using definition [START_REF] Lhuillier | Phenomenology of inertia effects in a dispersed solid-fluid mixture[END_REF] we can write

dA dλ (0) = Ω(0) ∂L ∂ρ δ λ ρ + ∂L ∂Y δ λ Y + ∂L ∂u δ λ u + ∂L ∂(D t h) δ λ (D t h) + ∂L ∂α δ λ α + ∂L ∂Σ δ λ Σ + ∂L ∂(∇α)
δ λ (∇α) dxdt. ( 16)

Applying [START_REF] Lhuillier | Phenomenology of inertia effects in a dispersed solid-fluid mixture[END_REF] with the constraints (9) allows to express following relations between the infinitesimal variations

δ λ ρ = -∇ • (ρδ λ ϕ) , (17a)
δ λ Y = -∇Y T δ λ ϕ, (17b)
δ λ u = D t (δ λ ϕ) -δ λ ϕ T ∇ u, (17c)
δ λ (D t h) = 1 Σ δ λ (D t α) - D t h Σ δ λ Σ. (17d)
Recasting relations (17) into [START_REF] Cordesse | Coupling a hierarchy of diffuse interface model with kineticbased moment methods for spray atomization simulations in cryogenic rocket engines[END_REF] provides

Ω(0) [A T δϕ + B δα + C δΣ] dxdt = 0, (18)
A T = ∂ t ∂L ∂u + ∇ • [( ∂L ∂u T u T + (∇u) T ∂L ∂u T + ∂ t 1 Σ ∂L ∂D t h ∇α +∇ • 1 Σ ∂L ∂D t h ∇α u + 1 Σ ∂L ∂D t h (∇u) T ∇α -ρ ∇ ∂L ∂ρ T + ∂L ∂Y ∇Y, (19)
B= ∂L ∂α -∇ • ∂L ∂∇α -∂ t 1 Σ ∂L ∂D t h -∇ • 1 Σ ∂L ∂D t h u , (20)
C= ∂L ∂Σ - 1 Σ ∂L ∂D t h D t h. (21)
We can conclude that the Least Action Principles applied to the Lagrangian energy defined by (8) yields the following equations of motion

A = 0, B = 0, C = 0. ( 22a
)
Let us further express the equations of motions into a more familiar form. With the definition (8) of L one then has

∂L ∂ρ = |u| 2 2 -f -ρ ∂f ∂ρ , ∂L ∂Y = -ρ ∂f ∂Y , ∂L ∂u = ρu, (23a)
∂L ∂ (D t h) = mD t h, ∂L ∂Σ = -γ, ∂L ∂α = -ρ ∂f ∂α , ∂L ∂ (∇α) = σ∇α. (23b)
We obtain

A= ∂ t (ρu) + ∇ • ρuu T + ρ∇u • u + ∂ t m Σ D t h∇α + ∇ • m Σ D t h∇α u + m Σ D t h(∇u) T ∇α -ρ∇ 1 2 |u| 2 -f -ρ∂ ρ f -ρ∂ Y f ∇Y, (24)
B = ∂ t m Σ D t h + ∇ • m Σ D t h u + ρ∂ α f + ∇ • [σ∇α] , (25)
C = -γ - m Σ (D t h) 2 . ( 26
)
5 Final form of the system

We define the pressure p of the two-phase medium and the partial pressures p k of each phase and introduce a new variable w by setting

p = ρ 2 ∂f ∂ρ , p k = ρ 2 k ∂f ∂ρ k , w = D t α ρY Σ 2 , (27)
then by injecting relations (23) into ( 22) one obtains the system

                                       ∂ρ ∂t + ∇ • [ρu] = 0, ∂ρY ∂t + ∇ • [ρY u] = 0, ∂ρu ∂t + ∇ • (ρuu T ) + p + 1 2 m Σ 2 (D t α) 2 I d + σ∇α∇α T -σ |∇α| 2 2 I d = 0, D t α -ρY wΣ 2 = 0, D t w + 1 ρY m (p 2 -p 1 + ∇ • [σ∇α]) = 0, D t (ρΣ) - 2ρY wΣ γ (p 2 -p 1 + ∇ • [σ∇α]) = 0. (28a) (28b) (28c) (28d) (28e) (28f)
Remark 3: System (28) is a generalization of the system found in [START_REF] Drui | Small-scale kinematics of two-phase flows: identifying relaxation processes in separated-and disperse-phase flow models[END_REF] and degenerates towards it when considering the interfacial area density as a function of the volume fraction only and using the notation of the author one identifies ν = m/Σ. However the variable w is not the defined as the pulsation w found in [START_REF] Drui | Small-scale kinematics of two-phase flows: identifying relaxation processes in separated-and disperse-phase flow models[END_REF] Remark 4: System (28) is valid for any flow topology.

In the large scale momentum equation (28c), the terms function of the volume fraction gradient are common terms found in the literature [START_REF] Blanchard | A large scale multi-fluid/dispersed phase approach for spray generation in aeronautical fuel injectors. proceeeding[END_REF].

Equation (28e) is a small scale momentum equation on the variable w which can be interpreted as the small scale pulsation of any structures.

Neglecting second order terms and capillarity at large scale (σ = 0), the spectrum of System (28) yields (u, u, u, u, u

± ∂ ρ Π + Σ/ρ∂ Σ Π) with Π = p + 1/2mρ 2 Y 2 w 2 Σ 2 .
The sound speed is impacted by the small scale effects.

Conclusion

In the present contribution, we have designed a two-phase flow model that is able to account for two-scale kinematics and two-scale surface tension effects as well as subscale pulsation momentum using the Least Action Principle. The system obtained is an extension of the work of [START_REF] Drui | Small-scale kinematics of two-phase flows: identifying relaxation processes in separated-and disperse-phase flow models[END_REF] and degenerates naturally towards the system proposed in it. This is solid foundation on which to build a dissipative structure for the present model by using an entropy evolution equation as in [START_REF] Drui | Small-scale kinematics of two-phase flows: identifying relaxation processes in separated-and disperse-phase flow models[END_REF] and relying also on the recent work [START_REF] Cordesse | Supplementary conservative law for non-linear systems of PDEs with non-conservative terms: application to the modelling and analysis of complex fluid flows using computer algebra[END_REF]. We are also investigating the possibility of extending the degree at which the system is out of equilibrium, in particular as far as velocity of the phases are concerned [START_REF] Cordesse | Coupling a hierarchy of diffuse interface model with kineticbased moment methods for spray atomization simulations in cryogenic rocket engines[END_REF]. Including a more detailed description of the subscale geometry and topology in order to be consistent with [START_REF] Essadki | Adaptative Mesh Refinement and High Order Geometrical Moment Method for the Simulation of Polydisperse Evaporating Sprays[END_REF][START_REF] Essadki | Statistical modeling of the gas-liquid interface using geometrical variables: toward a unified description of the disperse and separated phase flows[END_REF] and providing a clear mechanism for distributing the information carried by the variables of the system over small and large scales are still a key issue and the subject of our current research.

A Normal perturbation of a regular closed surface

LetFig. 2 :

 2 Fig. 2: Closed volume undergoing normal variation

From ( 29 )

 29 one deduces that d dh (meas[S(h)]) = -2H loc S meas[S]. (30)

Acknowledgment

The research of P. Cordesse and R. Di Battista are supported by a CNES/ONERA and a DGA/Ecole polytechnique PhD grants respectively. The support of IFPEn, Ecole polytechnique and Initiative HPC@Maths (PIs F. Alouges and M. Massot) for M. Massot and R. Di Battista, and of CEA for Samuel Kokh are gratefully acknowledged. This work was conducted during the Summer Program 2018 at NASA Ames Research Center and the support and precious help of N.N. Mansour and F. Panerai are also gratefully acknowledged.