Effects of shrimp pond water on phytoplankton: importance of salinity and trophic status of the receiving environment |
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| Authors: | Alessandro Pereira Cardozo Clarisse Odebrecht |
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| Institution: | Instituto de Oceanografia, Universidade Federal do Rio Grande – FURG, , Rio Grande, RS, Brazil |
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| Abstract: | Aquaculture generates a large load of effluents rich in organic matter and nutrients that may be introduced into the environment. This study aimed to assess in a microcosm experiment, the effect of shrimp pond water mixed with Patos Lagoon estuary water on phytoplankton chlorophyll a and primary production, simulating two salinities. Chlorophyll a, dissolved inorganic nutrients and primary production were measured in two experiments. In Harvest I, salinity of shrimp pond and environment water was similar, and chlorophyll a showed different trends over time, according to the amount of nitrogen available. In Harvest II, with different salinities and high nutrient concentrations in environment water, chlorophyll a levels showed a similar increasing trend over time in all mixtures. Net primary production showed differences among treatments in the first sampling in Harvest I, but not in the second, whereas no differences were observed among treatments in Harvest II. We conclude that shrimp pond effluent can lead to short‐term variations in chlorophyll a and primary production levels, with similar salinities. Salinity differences result in lower chlorophyll a and primary production values than expected according to the nutrient input. Differences in salinity can be an important management strategy to choose the best harvest period. |
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| Keywords: | Chlorophyll Nutrients Patos Lagoon estuary Phytoplankton Primary Production Shrimp |
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