Presenter/Author Information

R. Zhao
Z. F. Yang
T. Sun

Keywords

phytoplankton community, diagnostic pigments, environmental flow, ecohydrodynamic modelling, the yellow river estuary

Start Date

1-7-2010 12:00 AM

Description

The response of ecological processes to hydrological processes is a critical issue in the assessment of environmental flow requirements in estuaries. Considering its representative function of the primary productivity in estuaries, the phytoplankton community was selected as the bioindicator to indicate the variation of ecosystems influenced by hydrological processes in estuaries. Based on the regression analysis, a response relation model was established for describing the relationship between characteristics of phytoplankton communities (chlorophyll a, Fucoxanthin, chlorophyll b, and pyridinin) and indicating factors including salinity, COD, ammonia nitrogen, and dissolved oxygen. The biomass objective of high nutritional level organisms, the biomass of phytoplankton communities, and the concentration of diagnostic pigments were proposed in the Yellow River Estuary according to the principle of nutritional energy flow of ecosystem. An ecohydrodynamic model combined a phytoplankton growth model and a hydrodynamic model was developed in order to simulate relationship between river discharges and preference of phytoplankton in the Yellow River Estuary. Threshold values of environmental flows in the estuary were determined based on objectives of ecosystem and the relationship between ecological processes and hydrological processes in the Yellow River Estuary. It is concluded that the maximum, medium, and minimum annual environmental flows account for 105~111%, 65~68% and 31.7~32.4% of natural runoff in the YRE.

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Jul 1st, 12:00 AM

Environmental flow requirements (EFRs) related to preference of phytoplankton in the Yellow River Estuary (YRE) based on an ecohydrodynamic model

The response of ecological processes to hydrological processes is a critical issue in the assessment of environmental flow requirements in estuaries. Considering its representative function of the primary productivity in estuaries, the phytoplankton community was selected as the bioindicator to indicate the variation of ecosystems influenced by hydrological processes in estuaries. Based on the regression analysis, a response relation model was established for describing the relationship between characteristics of phytoplankton communities (chlorophyll a, Fucoxanthin, chlorophyll b, and pyridinin) and indicating factors including salinity, COD, ammonia nitrogen, and dissolved oxygen. The biomass objective of high nutritional level organisms, the biomass of phytoplankton communities, and the concentration of diagnostic pigments were proposed in the Yellow River Estuary according to the principle of nutritional energy flow of ecosystem. An ecohydrodynamic model combined a phytoplankton growth model and a hydrodynamic model was developed in order to simulate relationship between river discharges and preference of phytoplankton in the Yellow River Estuary. Threshold values of environmental flows in the estuary were determined based on objectives of ecosystem and the relationship between ecological processes and hydrological processes in the Yellow River Estuary. It is concluded that the maximum, medium, and minimum annual environmental flows account for 105~111%, 65~68% and 31.7~32.4% of natural runoff in the YRE.