Abstract:
In marine ecosystems, rising atmospheric CO2 and climate change are associated
with concurrent shifts in temperature, circulation, stratification, nutrient
input, oxygen content, and ocean acidification, with potentially wideranging
biological effects. Population-level shifts are occurring because of
physiological intolerance to new environments, altered dispersal patterns,
and changes in species interactions. Together with local climate-driven invasion
and extinction, these processes result in altered community structure
and diversity, including possible emergence of novel ecosystems. Impacts are
particularly striking for the poles and the tropics, because of the sensitivity
of polar ecosystems to sea-ice retreat and poleward species migrations as
well as the sensitivity of coral-algal symbiosis to minor increases in temperature.
Midlatitude upwelling systems, like the California Current, exhibit
strong linkages between climate and species distributions, phenology, and
demography. Aggregated effects may modify energy and material flows as
well as biogeochemical cycles, eventually impacting the overall ecosystem
functioning and services upon which people and societies depend.
