AME 80:105-122 (2017)  -  DOI: https://doi.org/10.3354/ame01841

ABSTRACT: We conducted a mesocosm study to investigate the combined effect of organic enrichment and sediment resuspension by shrimp on phytoplankton communities in shrimp aquaculture ponds. Hence, the factorial design included 2 factors: (1) shrimp density with a concomitant increase of feed input, resulting in organic enrichment, and (2) access of shrimp to the sediments. Increasing feed input in the system raised the eutrophication state of the environment, characterized by an increase in phytoplankton biomass. Bioturbation enhanced: (1) mineralization of organic matter via the microbial loop, resulting in faster nutrient recycling, (2) primary production and (3) buffering capacity against eutrophication consequences. The phytoplankton community showed both large temporal variations of its taxonomic composition and resilience to treatments. A shift in species dominance from diatoms + dinoflagellates to green algae was observed in all treatments and coincided with meteorological and N pool changes. Results suggest that algal production was primarily limited by phosphorus and light at low (i.e. low feeding) and high (i.e. high feeding) eutrophication states, respectively. Growth rate of species to be a major factor favoring their dominance in the phytoplankton community in this highly dynamic ecosystem. Consequences for water column management are discussed.

KEY WORDS: Aquaculture · Litopenaeus stylirostris · Phytoplankton communities · Eutrophication · Bioturbation