Differential physiological responses to oxygen availability in early life stages of decapods developing in distinct environments
Alter, K and Paschke, K and Gebauer, P and Cumillaf, J-P and Portner, H-O, Differential physiological responses to oxygen availability in early life stages of decapods developing in distinct environments, Marine Biology: International Journal on Life in Oceans and Coastal Waters, 162 pp. 1111-1124. ISSN 0025-3162 (2015) [Refereed Article]
During development crustaceans experience a range of oxygen tensions (PO2) in their various developmental environments. Therefore, it is likely that they developed varying strategies to respond to hypoxic events during their ontogeny. We investigated short-term responses to various oxygen levels in early life stages of two anomuran decapods Petrolisthes laevigatus and Lithodes santolla that develop in different habitats. Embryos and juveniles of P. laevigatus inhabit the upper rocky intertidal and are regularly exposed to hypoxia during low tide, while larvae of this species inhabit well-oxygenated surface waters. L. santolla is a subtidal species that inhabits fjords and is frequently exposed to hypoxia due to stratification in this environment. Oxygen consumption (MO2), lactate content, RNA/DNA ratio, lactate dehydrogenase and superoxide dismutase (SOD) activities were measured in embryos, larvae and juveniles after exposure to PO2s of 3–21 kPa for 24 h. Results indicated considerable variation in hypoxia tolerances among the ontogenetic stages of both species. Embryos of both species relied on anaerobiosis at all tested PO2 yet were able to regulate MO2 until 15 kPa. In contrast, larvae of L. santolla were oxyconformers, while those of P. laevigatus continued to oxyregulate in conjunction with a decrease in SOD activities in response to low PO2. Juveniles of P. laevigatus were more sensitive to hypoxia than those of L. santolla as all tested parameters were affected at higher PO2 in the former. This study shows that aerobic and anaerobic metabolism, antioxidant defence and protein synthesis of early life stages are diverse and reflect the variety of inhabited environments.
physiological response, oxygen availability, decapods, early life stages