Ocean Deoxygenation Conference | Kiel 2018

Man-induced global climate changes are leading to severe modifications on the ocean’s physicochemistry, with far-reaching consequences for marine life. While CO2 emissions are warming and acidifying seawater masses, oxygen content is diminishing due to decreased oxygen-solubility, increased stratification, augmented microbial respiration, and other abiotic/biotic processes. Following well-established theoretical model predictions, we performed hierarchical mixed-model meta-analyses testing the effects of climate change-related stressors (ocean acidification, warming, both aforesaid stressors combined, and hypoxia) across different biological responses, taxonomic groups, ontogenic life stages and climate regions (i.e. moderators). Overall, and within tested moderators, hypoxia affected marine life to a starkly greater extent than the other stressors. Thus, decreased mean oxygen content, and consequent expansion/forming of oceanic hypoxic areas, are likely to become a primary deterrent for life in future oceans.