Geoscience Reference
In-Depth Information
CHAPTER 10
James P. Barry, Stephen Widdicombe, and Jason M. Hall-Spencer
be difi cult to detect amidst the variability associ-
ated with other human and non-human factors, and
the greatest impacts are expected to occur as acidii -
cation intensii es through this century.
In theory, large and rapid environmental changes
are expected to decrease the stability and produc-
tivity of ecosystems due to a reduction in biodiver-
sity caused by the loss of sensitive species that play
important roles in energy l ow (i.e. food web func-
tion) or other processes (e.g. ecosystem engineers;
Cardinale
et al.
2006). In practice, however, most
research concerning the biological effects of ocean
acidii cation has focused on aspects of the perform-
ance and survival of individual species during
short-term studies, assuming that a change in indi-
vidual performance will inl uence ecosystem func-
tion. By their nature, controlled experimental
studies are limited in both space and time, and thus
may not capture important processes (e.g. acclima-
tization and adaptation, multispecies biological
interactions, chronic low-level impacts) that can
ultimately play large roles in the response of marine
systems to ocean acidii cation. This 'scaling up'
from individual- to ecosystem-level effects is the
most challenging goal for research on the potential
effects of ocean acidii cation.
To plan for the future, society needs information to
understand how ocean acidii cation and other envi-
ronmental changes will affect i sheries, aquaculture,
and other services deriving from the efi cient func-
tion of marine ecosystems. The inl ux of fossil fuel
CO
2
into the upper ocean from the atmosphere is
altering the chemistry of ocean waters at a faster
rate and greater magnitude than is thought to have
10.1 Introduction
The biodiversity of the oceans, including the strik-
ing variation in life forms from microbes to whales
and ranging from surface waters to hadal trenches,
forms a dynamic biological framework enabling the
l ow of energy that shapes and sustains marine eco-
systems. Society relies upon the biodiversity and
function of marine systems for a wide range of serv-
ices as basic as producing the seafood we consume
or as essential as generating much of the oxygen we
breathe. Perhaps most obvious is the global seafood
harvest totalling over 100 Mt yr
-1
(82 and 20 Mt in
2008 for capture and aquaculture, respectively; FAO
2009 ) from i shing effort that expands more broadly
and deeper each year as i shery stocks are depleted
( Pauly
et al.
2003). Less apparent ecosystem services
linked closely to biodiversity and ecosystem func-
tion are waste processing and improved water
quality, elemental cycling, shoreline protection, rec-
reational opportunities, and aesthetic or educational
experiences (Cooley
et al.
2009 ).
There is growing concern that ocean acidii cation
caused by fossil fuel emissions, in concert with the
effects of other human activities, will cause signii -
cant changes in the biodiversity and function of
marine ecosystems, with important consequences
for resources and services that are important to
society. Will the effects of ocean acidii cation on eco-
systems be similar to those arising from other envi-
ronmental perturbations observed during human
or earth history? Although changes in biodiversity
and ecosystem function due to ocean acidii cation
have not yet been widely observed, their onset may
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