Stratification strength and light climate explain variation in chlorophyll a at the continental scale in a European multilake survey in a heatwave summer
Authors: Donis Daphne , Mantzouki Evanthia , McGinnis Daniel F. , Vachon Dominic , Gallego Irene , Grossart Hans‐Peter , de Senerpont Domis Lisette N. , Teurlincx Sven , Seelen Laura , Lürling Miquel , Verstijnen Yvon , Maliaka Valentini , Fonvielle Jeremy , Visser Petra M. , Verspagen Jolanda , van Herk Maria , Antoniou Maria G. , Tsiarta Nikoletta , McCarthy Valerie , Perello Victor C. , Machado‐Vieira Danielle , de Oliveira Alinne Gurjão , Maronić Dubravka Špoljarić , Stević Filip , Pfeiffer Tanja Žuna , Vucelić Itana Bokan , Žutinić Petar , Udovič Marija Gligora , Plenković‐Moraj Anđelka , Bláha Luděk , Geriš Rodan , Fránková Markéta , Christoffersen Kirsten Seestern , Warming Trine Perlt , Feldmann Tõnu , Laas Alo , Panksep Kristel , Tuvikene Lea , Kangro Kersti , Koreivienė Judita , Karosienė Jūratė , Kasperovičienė Jūratė , Savadova‐Ratkus Ksenija , Vitonytė Irma , Häggqvist Kerstin , Salmi Pauliina , Arvola Lauri , Rothhaupt Karl , Avagianos Christos , Kaloudis Triantafyllos , Gkelis Spyros , Panou Manthos , Triantis Theodoros , Zervou Sevasti‐Kiriaki , Hiskia Anastasia , Obertegger Ulrike , Boscaini Adriano , Flaim Giovanna , Salmaso Nico , Cerasino Leonardo , Haande Sigrid , Skjelbred Birger , Grabowska Magdalena , Karpowicz Maciej , Chmura Damian , Nawrocka Lidia , Kobos Justyna , Mazur‐Marzec Hanna , Alcaraz‐Párraga Pablo , Wilk‐Woźniak Elżbieta , Krztoń Wojciech , Walusiak Edward , Gagala‐Borowska Ilona , Mankiewicz‐Boczek Joana , Toporowska Magdalena , Pawlik‐Skowronska Barbara , Niedźwiecki Michał , Pęczuła Wojciech , Napiórkowska‐Krzebietke Agnieszka , Dunalska Julita , Sieńska Justyna , Szymański Daniel , Kruk Marek , Budzyńska Agnieszka , Goldyn Ryszard , Kozak Anna , Rosińska Joanna , Szeląg‐Wasielewska Elżbieta , Domek Piotr , Jakubowska‐Krepska Natalia , Kwasizur Kinga , Messyasz Beata , Pełechata Aleksandra , Pełechaty Mariusz , Kokocinski Mikolaj , Madrecka‐Witkowska Beata , Kostrzewska‐Szlakowska Iwona , Frąk Magdalena , Bańkowska‐Sobczak Agnieszka , Wasilewicz Michał , Ochocka Agnieszka , Pasztaleniec Agnieszka , Jasser Iwona , Antão‐Geraldes Ana M. , Leira Manel , Vasconcelos Vitor , Morais Joao , Vale Micaela , Raposeiro Pedro M. , Gonçalves Vítor , Aleksovski Boris , Krstić Svetislav , Nemova Hana , Drastichova Iveta , Chomova Lucia , Remec‐Rekar Spela , Elersek Tina , Hansson Lars‐Anders , Urrutia‐Cordero Pablo , Bravo Andrea G. , Buck Moritz , Colom‐Montero William , Mustonen Kristiina , Pierson Don , Yang Yang , Richardson Jessica , Edwards Christine , Cromie Hannah , Delgado‐Martín Jordi , García David , Cereijo Jose Luís , Gomà Joan , Trapote Mari Carmen , Vegas‐Vilarrúbia Teresa , Obrador Biel , García‐Murcia Ana , Real Monserrat , Romans Elvira , Noguero‐Ribes Jordi , Duque David Parreño , Fernández‐Morán Elísabeth , Úbeda Bárbara , Gálvez José Ángel , Catalán Núria , Pérez‐Martínez Carmen , Ramos‐Rodríguez Eloísa , Cillero‐Castro Carmen , Moreno‐Ostos Enrique , Blanco José María , Rodríguez Valeriano , Montes‐Pérez Jorge Juan , Palomino Roberto L. , Rodríguez‐Pérez Estela , Hernández Armand , Carballeira Rafael , Camacho Antonio , Picazo Antonio , Rochera Carlos , Santamans Anna C. , Ferriol Carmen , Romo Susana , Soria Juan Miguel , Özen Arda , Karan Tünay , Demir Nilsun , Beklioğlu Meryem , Filiz Nur , Levi Eti , Iskin Uğur , Bezirci Gizem , Tavşanoğlu Ülkü Nihan , Çelik Kemal , Ozhan Koray , Karakaya Nusret , Koçer Mehmet Ali Turan , Yilmaz Mete , Maraşlıoğlu Faruk , Fakioglu Özden , Soylu Elif Neyran , Yağcı Meral Apaydın , Çınar Şakir , Çapkın Kadir , Yağcı Abdulkadir , Cesur Mehmet , Bilgin Fuat , Bulut Cafer , Uysal Rahmi , Latife Köker , Akçaalan Reyhan , Albay Meriç , Alp Mehmet Tahir , Özkan Korhan , Sevindik Tuğba Ongun , Tunca Hatice , Önem Burçin , Paerl Hans , Carey Cayelan C. , Ibelings Bastiaan W. 
Published: October 2021

To determine the drivers of phytoplankton biomass, we collected standardized morphometric, physical, and biological data in 230 lakes across the Mediterranean, Continental, and Boreal climatic zones of the European continent. Multilinear regression models tested on this snapshot of mostly eutrophic lakes (median total phosphorus [TP] = 0.06 and total nitrogen [TN] = 0.7 mg L−1), and its subsets (2 depth types and 3 climatic zones), show that light climate and stratification strength were the most significant explanatory variables for chlorophyll a (Chl a) variance. TN was a significant predictor for phytoplankton biomass for shallow and continental lakes, while TP never appeared as an explanatory variable, suggesting that under high TP, light, which partially controls stratification strength, becomes limiting for phytoplankton development. Mediterranean lakes were the warmest yet most weakly stratified and had significantly less Chl a than Boreal lakes, where the temperature anomaly from the long‐term average, during a summer heatwave was the highest (+4°C) and showed a significant, exponential relationship with stratification strength. This European survey represents a summer snapshot of phytoplankton biomass and its drivers, and lends support that light and stratification metrics, which are both affected by climate change, are better predictors for phytoplankton biomass in nutrient‐rich lakes than nutrient concentrations and surface temperature.