Environmental Engineering Reference
In-Depth Information
Climate change and climate variability have occurred throughout
history and natural systems have developed a capacity to adapt, which will
help them to mitigate the impact of future changes. However, two factors
will limit this adaptive capacity in future: (
i
) the rate of future climate
change is predicted to be more rapid than previous natural changes; and, (
ii
)
the resilience of species and systems is being compromised by concurrent
pressures, including fi shing (Planque et al. 2010), loss of biodiversity
(including genetic diversity), habitat destruction, pollution, introduced
and invasive species and pathogens.
Recent fi ndings on climate change impacts on marine ecosystems and
fi sheries can be divided into observational studies of past and current effects
of climate change, and modelling studies of future impacts (Roesig et al.
2004). By the way, Brander (2010) presented some studies which included
both observation and modelling, as well as some empirically based models
(e.g. they use functional relationships which are statistically derived from
observations).
There is now a wealth of evidence of impacts of recent climate change
on distribution, species composition, seasonality and production in marine
and freshwater systems. A very small selection from the large number of
recent papers which analyze climate effects on a variety of taxa includes:
phytoplankton (Richardson and Schoeman 2004), global primary production
(Schmittner 2005), krill in the Southern Ocean (Atkinson et al. 2004),
plankton in the North Atlantic (Richardson and Schoeman 2004), tropical
tuna (Lehodey et al. 2003), sardine and anchovy in Eastern Boundary
currents (Chavez et al. 2003) and fi sh species in North European shelf seas
(Perry et al. 2005).
Several of the most important effects on the marine environment linked
to Climate Changes which have been recognized include: (
i
) Changes in
global marine primary production; (
ii
) Cascade effect of changes in primary
and secondary production on future biological production; (
iii
) Regional
consequences of changes in primary poduction; (
iv
) Regional changes in
distribution and phenology of plankton and other organisms; (
v
) Spread
of pathogens; among others. Brief comments on each of them are included
in the following paragraphs.
Changes in global marine primary production
According to Brander (2010), three groups of factors govern the biological
response: (
i
) warming, (
ii
) light, as determined by ice cover, cloudiness
and surface mixed-layer thickness, and (
iii
) altered nutrient supply due
to changed vertical stability and nutrient fl ux. Predicted climate induced
