Phytoplankton functional responses induced by extreme hydrological events in a tropical reservoir

Mariana R A Costa; Maria M L Cardoso; Géza B Selmeczy; Judit Padisák; Vanessa Becker

doi:10.1007/s10750-023-05241-3

Phytoplankton functional responses induced by extreme hydrological events in a tropical reservoir

Hydrobiologia. 2023 May 15:1-19. doi: 10.1007/s10750-023-05241-3. Online ahead of print.

Authors

Mariana R A Costa^{1

2}, Maria M L Cardoso³, Géza B Selmeczy^{1

4}, Judit Padisák^{1

4}, Vanessa Becker^{2

5}

Affiliations

¹ ELKH-PE Limnoecology Research Group, Egyetem u. 10, Veszprém, 8200 Hungary.
² Programa de Pós-Graduação em Ecologia, Departamento de Ecologia, Universidade Federal do Rio Grande do Norte, Av. Senador Salgado Filho 3000, Natal, RN Brazil.
³ Secretaria da Educação da Ciência e Tecnologia do Estado da Paraíba, Avenida Dr. João da Mata, nº 200, Jaguaribe, João Pessoa, PB Brasil.
⁴ University of Pannonia, Center of Natural Science, Limnology Research Group, Egyetem u. 10, H-8200 Veszprém, Hungary, University of Pannonia, Egyetem u. 10, Veszprém, 8200 Hungary.
⁵ Departamento de Engenharia Civil e Ambiental, Universidade Federal do Rio Grande do Norte, Av. Senador Salgado Filho 3000, Natal, RN Brasil.

Abstract

Climate change is affecting the global hydrological cycle, causing drastic changes in precipitation patterns. Extreme climatic events are becoming more frequent and intense than in the past, leading to water-level fluctuations and affecting aquatic ecosystems. Semiarid regions are very susceptible to changing climate. We analyzed a 10 years dataset from a tropical semiarid reservoir during extreme hydrological events (heavy rains and prolonged drought), and evaluated phytoplankton functional responses to environmental conditions. We found, as hypothesized, that phytoplankton functional structure change in a temporal scale due to water-volume fluctuation induced by the rainfall pattern. Depth and inorganic material acted as environmental filters selecting phytoplankton groups. High water level seems to improve water quality and low water level worsen it. Colonial and filamentous cyanobacteria dominate the wet period; however, it may have a critical threshold during severe periods of drought, which will lead to dominance of groups well adapted to low light conditions and with mixotrophic metabolism. Phytoplankton functional approaches can simplify phytoplankton identification and reflect better the environmental conditions than the taxonomic approach. Therefore, these approaches can help to understand the shifts in aquatic ecosystems under extreme hydrological events and predict functional response of phytoplankton being an important tool to water management and conservation.

Supplementary information: The online version contains supplementary material available at 10.1007/s10750-023-05241-3.

Keywords: Climate change; Cyanobacteria; Extreme drought; Extreme rainfall; Functional classifications; Mixoplankton.

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