1. Nutrient ratios and the complex structure of phytoplankton communities in a highly turbid estuary of Southeast Asia
- Author
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Kha Thi Pham, Jean-Pascal Torréton, Xavier Mari, Emma Rochelle-Newall, Thuoc Van Chu, Thierry Bouvier, Yvan Bettarel, Olivier Pringault, Corinne Bouvier, Huyen Minh Thi Nguyen, Ecosystèmes lagunaires : organisation biologique et fonctionnement (ECOLAG), Université Montpellier 2 - Sciences et Techniques (UM2)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS), Ecologie des systèmes marins côtiers (Ecosym), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Microorganismes : Génome et Environnement (LMGE), Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), MARine Biodiversity Exploitation and Conservation (UMR MARBEC), Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut de Recherche pour le Développement (IRD), Hôpital de la Timone [CHU - APHM] (TIMONE), Institut d'écologie et des sciences de l'environnement de Paris (iEES Paris), Institut National de la Recherche Agronomique (INRA)-Sorbonne Université (SU)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université Montpellier 2 - Sciences et Techniques (UM2)-Université Montpellier 1 (UM1), Laboratoire Microorganismes : Génome et Environnement - Clermont Auvergne (LMGE), Université Clermont Auvergne (UCA)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche pour le Développement (IRD)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Institut d'écologie et des sciences de l'environnement de Paris (IEES (UMR_7618 / UMR_D_242 / UMR_A_1392 / UM_113) )
- Subjects
0106 biological sciences ,SALINITE ,Salinity ,PHYTOPLANCTON ,DIVERSITE SPECIFIQUE ,010501 environmental sciences ,STRUCTURE DE POPULATION ,01 natural sciences ,Nutrient ,PHOSPHATE ,Water Pollutants ,ComputingMilieux_MISCELLANEOUS ,General Environmental Science ,geography.geographical_feature_category ,biology ,Ecology ,Temperature ,NITRITE ,Phosphorus ,General Medicine ,CHLOROPHYLLE ,Pollution ,Oceanography ,Vietnam ,Dinoflagellida ,ESTUAIRE ,Seasons ,Estuaries ,NITRATE ,Dinophyceae ,Environmental Monitoring ,Nitrogen ,Management, Monitoring, Policy and Law ,ABONDANCE ,[SDV.EE.ECO]Life Sciences [q-bio]/Ecology, environment/Ecosystems ,Phytoplankton ,Temperate climate ,Dominance (ecology) ,Seawater ,14. Life underwater ,0105 earth and related environmental sciences ,Diatoms ,geography ,TOXICITE ,010604 marine biology & hydrobiology ,fungi ,Estuary ,Global change ,TURBIDITE ,NUTRIMENT ,15. Life on land ,biology.organism_classification ,13. Climate action ,human activities - Abstract
Phytoplankton diversity and abundance in estuarine systems are controlled by many factors. Salinity, turbidity, and inorganic nutrient concentrations and their respective ratios have all been proposed as principal factors that structure phytoplankton diversity and influence the emergence of potentially toxic species. Although much work has been conducted on temperate estuaries, less is known about how phytoplankton diversity is controlled in tropical, monsoonal systems that are subject to large, seasonal shifts in hydrology and to rapidly changing land use. Here, we present the results of an investigation into the factors controlling phytoplankton species composition and distribution in a tropical, monsoonal estuary (Bach Dang estuary, North Vietnam). A total of 245 taxa, 89 genera from six algal divisions were observed. Bacillariophyceae were the most diverse group contributing to 51.4 % of the microalgal assemblage, followed by Dinophyceae (29.8 %), Chlorophyceae (10.2 %), Cyanophyceae (3.7 %), Euglenophyceae (3.7 %) and Dictyochophyceae (1.2 %). The phytoplankton community was structured by inorganic nutrient ratios (DSi:DIP and DIN:DIP) as well as by salinity and turbidity. Evidence of a decrease in phytoplankton diversity concomitant with an increase in abundance and dominance of certain species (e.g., Skeletonema costatum) and the appearance of some potentially toxic species over the last two decades was also found. These changes in phytoplankton diversity are probably due to a combination of land use change resulting in changes in nutrient ratios and concentrations and global change as both rainfall and temperature have increased over the last two decades. It is therefore probable in the future that phytoplankton diversity will continue to change, potentially favoring the emergence of toxic species in this system.
- Published
- 2014