Effects of freshets on phytoplankton dynamics in a freshwater tidal estuary (Schelde, Belgium)
Muylaert, K.; Van Wichelen, J.; Sabbe, K.; Vyverman, W. (2001). Effects of freshets on phytoplankton dynamics in a freshwater tidal estuary (Schelde, Belgium). Arch. Hydrobiol. 150(2): 269-288
In: Archiv für Hydrobiologie. Schweizerbart'sche Verlagsbuchhandlung: Stuttgart. ISSN 0003-9136, meer
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| Trefwoorden |
Algae > Diatoms
Aquatic communities > Plankton > Phytoplankton
Aquatic communities > Plankton > Zooplankton
Characteristics > Productivity
Chemical compounds > Silicon compounds > Silica
Chemicals > Organic compounds > Organic nitrogen compounds > Heterocyclic nitrogen compounds > Porphyrins > Lipochromes > Chlorophyll
Chlorophyll
Community
Flushing
Production rate > Productivity
Productivity
River
Water
Water bodies > Coastal waters > Coastal landforms > Coastal inlets > Estuaries
ANE, België [Marine Regions]; ANE, Nederland, Westerschelde [Marine Regions]; België, Schelde R. [Marine Regions]; Nederland [Marine Regions]
Marien/Kust; Brak water; Zoet water |
| Author keywords |
Zooplankton grazing; Silica limitation; Flushing events; Freshwater tidal estuary; Limitation |
| Abstract |
From August to October 1996, a station in the freshwater tidal reaches of the Schelde estuary was sampled every two days to study short-term changes in the phytoplankton community. The monitoring study started after a long period of low and constant discharge and our data suggest that at that time, phytoplankton productivity was bottom-up limited by silica and/or top-down controlled by grazers. Rainfall in the middle of August resulted in a flushing of almost half of the estuarine volume upstream of our monitoring station. This fresher ended the period of limitation by removing grazers as well as supplying new silica, while having no direct effect on total phytoplankton biomass. It was followed by a gradual increase in phytoplankton biomass. An extremely high runoff event caused by a storm at the end of August resulted in a flushing of the entire freshwater tidal reach. Phytoplankton biomass dropped and the estuarine phytoplankton community was replaced with one of riverine origin which was not adapted to the growth conditions prevailing within the estuary. Afterwards, autochthonous phytoplankton populations were not able to recover due to the presence of grazers and a general decrease in light levels and temperature. Our results illustrate how freshets may influence phytoplankton dynamics directly through longitudinal transport of phytoplankton populations and indirectly by influencing nutrient levels and grazer populations. |
| Dataset |
- Laboratory of Protistology and Aquatic Ecology (PAE). Ugent; De Vlaamse Waterweg NV: Belgium; (2020): OMES: Monitoring phytoplankton in the Zeeschelde., meer
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