Rocky reefs, kelp beds, sea grasses and shallow shelf habitats are most vulnerable to ocean acidification, temperature change and ultraviolet radiation. Least vulnerable are hard shelves, deep slopes, canyons, seafloors and seamount habitats.
These are the findings of researcher Thomas Okey and colleagues, who investigated climate-change responses on various marine ecosystems of coastal southern British Columbia. Okey and colleagues published their findings in Ocean & Coastal Management.
The researchers looked at exposure, sensitivity and adaptive capacity, which together define vulnerability. Exposure was defined as a measure of current climate impacts. Sensitivity was defined as a measure of ecosystem response to climate and other stressors. Adaptive capacity was defined as the ratio of the cumulative impacts of human and environmental stressors (assuming that already-stressed marine ecosystems will take longer to bounce back from future climate impacts). Ultimately, vulnerability was calculated as potential climate impacts multiplied by other cumulative human and environmental impacts.
Among the three impact variables, acidification’s impact will be the most variable, while the impacts of warming waters and higher UV radiation will be more uniform, the study showed. The greatest impacts will be seen in shallower zones. Straits showed greater vulnerability to the three impact variables than open ocean (see graphic below), a difference the researchers attribute to current environmental stresses.
The integrated management of these multiple stressors in advance of climate impacts could improve marine ecosystem resilience. The spatial and 3-D information in this study could identify the habitats most vulnerable to change, allowing prioritization of regional management and adaptation actions. Although the study examined coastal British Columbia, the lessons learned and research methods could be applied to the coasts of the Northwest United States.
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