Effects of direct ocean CO2 injection on deep-sea meiofauna

Purposeful deep-sea carbon dioxide sequestration by direct injection of liquid CO(2) into the deep waters of the ocean has the potential to mitigate the rapid rise in atmospheric levels of greenhouse gases. One issue of concern for this carbon sequestration option is the impact of changes in seawater chemistry caused by CO(2) injection on deep-sea ecosystems. The effects of deep-sea carbon dioxide injection on infaunal deep-sea organisms were evaluated during a field experiment in 3600 m depth off California, in which liquid CO(2) was released on the seafloor. Exposure to the dissolution plume emanating from the liquid CO(2) resulted in high rates of mortality for flagellates, amoebae, and nematodes inhabiting sediments in close proximity to sites of CO(2) release. Results from this study indicate that large changes in seawater chemistry (i.e. pH reductions of similar to0.5-1.0 pH units) near CO(2) release sites will cause high mortality rates for nearby infaunal deep-sea communities.