Responses of marine organisms to climate change and ocean acidification across ocean regions

Chair: Ken Caldeira

Elvira Poloczanska(1)

1 CSIRO Oceans and Atmosphere, Brisbane, Qld 4072, Australia

Ocean acidification is occurring concurrently with other physical and chemical changes in the ocean as a result of anthropogenic greenhouse gas emissions, with serious implications for marine species and concomitant risks to marine industries dependent on those species. I present the results of a meta-analysis of the responses of marine ecosystems and species to climate change and ocean acidification across ocean regions, from the boreal and polar systems to oligotrophic tropical seas.

I draw on a marine climate-change impacts database comprising of >1900 observations of marine ecological impacts of climate change from >230 peer-reviewed publications. Observations of ecological responses were classified as changes in abundance, distribution, phenology, demography and calcification. Each observation was assessed for consistency with theoretical expectations from climate change and includes examples where responses were equivocal or zero

I present a global map of species responses to climate change and ocean acidification. The volume and type of evidence of species responses to climate change is variable across ocean regions and taxonomic groups, with much evidence from high latitude northern hemisphere oceans. In contrast, observations of changing calcification were predominantly from tropical oceans, reflecting the dominance of coral studies. At a species level, impacts on the abundance and distribution (including depth shifts) of marine species are widely reported (41%), while less evidence exists for phenology change (14%) and few observations of demography (3%) and changing calcification (2%), presumably reflecting the very recent emergence of ocean acidification as a concern and in the development of technologies for long-term monitoring of ocean acidification.