Changing Oceans, Changing Habitat

We've already posted about the Changing Oceans special issue of Science, but we think it's important to focus on how climate change is affecting marine wildlife habitat.

Marine ecosystems are centrally important to the biology of the planet, yet a comprehensive understanding of how anthropogenic climate change is affecting them has been poorly developed. Recent studies indicate that rapidly rising greenhouse gas concentrations are driving ocean systems toward conditions not seen for millions of years, with an associated risk of fundamental and irreversible ecological transformation. The impacts of anthropogenic climate change so far include decreased ocean productivity, altered food web dynamics, reduced abundance of habitat-forming species, shifting species distributions, and a greater incidence of disease. Although there is considerable uncertainty about the spatial and temporal details, climate change is clearly and fundamentally altering ocean ecosystems. Further change will continue to create enormous challenges and costs for societies worldwide, particularly those in developing countries.

Authors Hoegh-Guldberg and Bruno acknowledge that "change has been the norm as Earth has swung through a variety of states in which life has prospered, dwindled, or experienced calamitous declines" as well as the fact that "long-term studies of climate change in the oceans are rare by comparison to those on land." They go on to cite study after study indicating that there is plenty of evidence that change is rapid and driven, at least in part, by human activity. Changing ocean temperatures and composition mean changing currents and nutrient cycles.

Especially visible are the effects of climate change on "habitat-forming species such as corals, sea grass, mangroves, salt marsh grasses, and oysters." When these species are at risk, so are the many species dependent on them. Of course, warmer oceans expands the potential habitat for some. We see warm-water species ranging from sea turtles to sea urchins expanding beyond their normal ranges, but the expansion of warm waters also means the expansion of marine-based diseases and parasites.

Over all, it's important that the conservation community to continue its research as we try to understand more about our changing oceans. We remain committed to playing our role in contributing to scientific understanding. We also continue to take cutting-edge science to the field as we work to mitigate climate change and restore and conserve wildlife habitat from ridge to reef.