Science Highlights

Zooplankton in the Pearl River Estuary

Marine hypoxia has become a worldwide environmental issue in coastal ocean habitats, with devastating effects on the sustainability of ecosystems in these area. Hypoxia is a main concern related to global warming and anthropogenic pollution because of the negative impacts on survival of zooplankton and fishes inhabiting these waters. This may in turn change the distribution, behaviour, and metabolic rate of zooplankton, food web structure, carbon flux and fisheries. Copepods correspond to most of zooplankton abundance and have been considered a model group to evaluate changes in bio-oceanography, especially for their rapid response to changing conditions such as temperature, oxygen, as well as food quantity and quality. The main goal of our research is to determine whether grazing and metabolism rates of copepods are affected by low oxygen concentrations associated with coastal hypoxia. We found that low oxygen conditions would limit the metabolism of copepods and the responses to hypoxia were species-specific, reflected in a potential reduction of grazing and respiration rate.