Geoscience Reference
In-Depth Information
munities, will be essential for examining the effects
of chronic ocean acidii cation. One important goal of
such studies will be to understand if and how ocean
acidii cation and other anthropogenic environmental
changes will ultimately affect the function of marine
communities. Will ocean acidii cation drive commu-
nities past 'tipping points' with dramatic shifts in
ecosystem function and ecosystem services, as has
been proposed for coral reef systems (Hoegh-
Guldberg
et al.
2007 )? New experimental approaches
to evaluate the response of organisms to ocean acidi-
i cation and other concurrent environmental changes
and human inl uences, including (1) the potential for
acclimatization and adaptation by key taxa, (2) scal-
ing up from individuals to populations, multispecies
assemblages, and communities over long timescales
and in various ecosystems, and (3) effects on energy
l ow through marine food webs and the eventual
consequences for top predators, including marine
i sheries, will provide society with new tools and
understanding concerning how the resources and
services society depends upon may be affected in a
changing ocean.
function of marine ecosystems than other anthropo-
genic activities, but its inl uence in various commu-
nities is expected to increase as ocean acidii cation
intensii es through this century. In some ecosystems,
it is possible that ocean acidii cation, along with
other anthropogenic environmental changes, may
alter ecosystem function by reducing biodiversity
and either approaching or potentially crossing eco-
logical tipping points, with unpredictable effects on
ecosystem function and services for society.
10.9 Acknowledgements
J.P.B. is grateful for support from the David and
Lucille Packard Foundation, and to F. Melzner and
W. Fischer who provided important and very help-
ful comments on the manuscript.
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10.8 Conclusion
Ocean acidii cation represents a large and very rapid
change in the chemistry of the ocean, with the poten-
tial to affect the biodiversity and function of a vari-
ety of marine ecosystems. Although broad effects of
anthropogenic ocean acidii cation have not yet been
observed, they may be difi cult to detect amid the
inl uence of other factors, and are expected to emerge
and increase through this century. Ocean acidii ca-
tion is considered a threat mainly due to the expected
reduction in calcii cation in various species as the
pH of ocean waters decreases. Reduced calcii cation,
growth, and survival by corals in coral reef habitats
and deep-sea coral-dominated communities are
expected in response to ocean acidii cation, with
ecosystem-wide impacts due to the indirect effects
on coral-associated taxa. Shifts in phytoplankton
communities and intermediate prey groups due to
differential responses to ocean acidii cation may
drive changes in energy l ow through marine food
webs, ultimately inl uencing the productivity and
stability of marine i sheries. Ocean acidii cation is
currently considered to have lesser impacts on the
