Effects of hypoxia on copepod egg hatching success: An in situ study

Hypoxia is a global concern, affecting marine ecosystems. In this study, we investigated the effect of low Oxygen concentration on the egg hatching rate of Acartia erythraea in Gamak Bay, where hypoxia frequently occurs in summer. Three in situ experiments were conducted in June and August 2013 and July 2014. Environmental parameters, including the water temperature, salinity, dissolved Oxygen (DO) concentration, and pH, were measured during the experiments. Hypoxic conditions had a significant negative impact on the hatching rate of A. erythraea eggs; hatching rate was positively correlated with the DO concentration (r = 0.843, p < 0.01) and pH (r = 0.600, p < 0.01). These findings suggest that hypoxia has significant negative impacts on recruitment of planktonic A. erythraea, with potential implications for overall plankton and nekton dynamics.