Hydrodynamics Regulate Longitudinal Plankton Community Structure in an Alpine Cascade Reservoir System

Area of Science:

• Ecology
• Limnology
• Environmental Science

Background:

• Cascade reservoir construction significantly alters aquatic biotic communities.
• Spatial-temporal plankton dynamics in alpine cascade systems remain under-explored.
• Understanding these dynamics is crucial for managing Yellow River region ecosystems.

Purpose of the Study:

• To investigate the effects of environmental factors on longitudinal plankton patterns in an alpine cascade reservoir system.
• To differentiate the regulatory roles of hydrological and nutrient conditions on phytoplankton and zooplankton communities.
• To establish relationships between phytoplankton and zooplankton community structures.

Main Methods:

• A 5-year field study was conducted in an alpine cascade reservoir system.
• Environmental factors, phytoplankton, and zooplankton communities were monitored.
• Statistical analyses were used to correlate environmental variables with plankton community metrics.

Main Results:

• Hydrological regime (drainage rate, sediment) primarily regulated phytoplankton species numbers, abundance, biovolume, and diversity indices (Shannon-Wiener H', Pielou J').
• Nutrient conditions (N:P ratio) negatively impacted phytoplankton abundance and biovolume but did not significantly affect species numbers.
• Zooplankton species numbers were mainly regulated by the hydrological regime, while abundance, biovolume, and diversity indices (H', J') were positively correlated with nutrient conditions and temperature.

Conclusions:

• Hydrological factors are key drivers of plankton community structure in alpine cascade reservoirs.
• Nutrient conditions play a significant role in zooplankton abundance and diversity, but less so for phytoplankton species richness.
• Phytoplankton and zooplankton communities exhibited positive correlations, suggesting linked responses to environmental gradients within the reservoir system.