Ocean acidification and the accompanying hypoxia, which have become increasingly important environmental stress factors, can have varying effects on marine organisms, such as impaired physiological metabolism and immune function. Here, I studied the effects of high pCO2 and low dissolved oxygen (DO) in European flat oyster Ostrea edulis. Changes in physiological and immunological parameters were investigated in oysters during 18 days of exposure at two different pH (7.90 and 7.30) and DO levels (7.5 and 2 mg L-1). Low pH and low DO reduced haemocye count and viability, both individually and in combination. Low pH and combined exposure decreased feeding and respiration, which exacerbated by duration. Low pH and low dissolved oxygen increased ammonia excretion rate, which exacerbated by time. I suggest that the low pH and low DO lead metabolic depression, impaired immune function, and alteration in energy allocation in oysters, which further collectively negatively affect fitness of the oyster.
Sezer N., 2025. Metabolic responses of the European flat oyster (Ostrea edulis) to combined ocean acidification and hypoxia. SSRN. Article.
