3 Populations and Pathways
103
In general, with the exception of antifreezes, most work on cold adaptation of
fish and invertebrates has been carried out on Antarctic species as these have been
effectively geographically isolated in a constantly cold environment for around
25–15 Ma BP and comprise a high percentage of endemic species (reviewed in
Clarke and Johnston 1996). In contrast the Arctic marine benthic fauna comprises
a relatively young assemblage characterised by species from either the Pacific
or Atlantic with notably few endemics (Dunton 1992). Hence comparisons of
Polar species can provide important information to separate phylogeny from cold
adaptation (cf. Verde et al. 2007).
Intimately linked to the subject of Polar environments is that of climate change.
Scientific opinion now largely supports the view of man-induced climate change
with a number of predicted scenarios for our environment in the future (IPCC 2007)
and the Polar regions are where warming is happening more rapidly than most other
places on the planet. Oceanic temperatures are predicted to rise by 2 ◦ C over the next
100 years (Murphy and Mitchell 1995) faster than in any period over the past million years or on record over the last Pleistocene glacial cycle (Zachos et al. 2001).
But along the Antarctic Peninsula regional climate change has been rapid with temperature rises in the Bellingshausen surface ocean sea of 1 ◦ C in 50 years (Meredith
and King 2005). But the situation is more complex and the effect of CO 2 emissions
is not only linked to temperature, but also ocean acidification and pH changes. In
the 250 years since the onset of the industrial revolution, atmospheric CO 2 levels
have risen from 280 to 381 ppm (Canadell et al. 2007) and are still rising rapidly.
CO 2 is taken up by the ocean and forms carbonic acid, thus reducing ocean pH, and
decreasing the saturation state (= increasing solubility) of calcium carbonate. Ocean
pH has fallen from an average 8.16–8.05 (Caldeira and Wicket 2003) and models
predict that pH at the ocean surface will continue to fall by an estimated 0.2–0.4
units by the year 2100 (Caldeira and Wicket 2003, 2005, Royal Society 2005, Cao
et al. 2007). These predicted changes in ocean pH are greater, and far more rapid,
than any experienced in the past 300 million years. Again, the Polar Regions will
be particularly affected as the Southern Ocean has among the lowest present-day
CaCO 3 saturation rate of any ocean region, and will therefore be among the first to
become undersaturated (Orr et al. 2005).
So clearly there is an urgent requirement to determine the effect of increased seawater temperatures and acidification on marine life. Not all organisms are affected
equally and while all those studied to date have been shown to be affected, it is
clear that some will adapt and survive (Dupont et al. 2008). We currently know
almost nothing about the genetic mechanisms and genomic basis of this phenoptypic plasticity. It is with this requirement that Polar species, in particular those in
the Antarctic are of great use, for example in the development of biomarkers for
climate change. The advantage of working on Antarctic species is that they are very
thermally sensitive (Peck et al. 2004) and their response is not confounded by pollution, which affects the rest of the planet. Therefore Antarctic organisms offer us
the cleanest signals for the effects of climate change and should be regarded as environmental sentinels. Integrated genomic and functional studies on Polar organisms
are in their infancy (Clark et al. 2004, Peck et al. 2005), but such studies are now
103
In general, with the exception of antifreezes, most work on cold adaptation of
fish and invertebrates has been carried out on Antarctic species as these have been
effectively geographically isolated in a constantly cold environment for around
25–15 Ma BP and comprise a high percentage of endemic species (reviewed in
Clarke and Johnston 1996). In contrast the Arctic marine benthic fauna comprises
a relatively young assemblage characterised by species from either the Pacific
or Atlantic with notably few endemics (Dunton 1992). Hence comparisons of
Polar species can provide important information to separate phylogeny from cold
adaptation (cf. Verde et al. 2007).
Intimately linked to the subject of Polar environments is that of climate change.
Scientific opinion now largely supports the view of man-induced climate change
with a number of predicted scenarios for our environment in the future (IPCC 2007)
and the Polar regions are where warming is happening more rapidly than most other
places on the planet. Oceanic temperatures are predicted to rise by 2 ◦ C over the next
100 years (Murphy and Mitchell 1995) faster than in any period over the past million years or on record over the last Pleistocene glacial cycle (Zachos et al. 2001).
But along the Antarctic Peninsula regional climate change has been rapid with temperature rises in the Bellingshausen surface ocean sea of 1 ◦ C in 50 years (Meredith
and King 2005). But the situation is more complex and the effect of CO 2 emissions
is not only linked to temperature, but also ocean acidification and pH changes. In
the 250 years since the onset of the industrial revolution, atmospheric CO 2 levels
have risen from 280 to 381 ppm (Canadell et al. 2007) and are still rising rapidly.
CO 2 is taken up by the ocean and forms carbonic acid, thus reducing ocean pH, and
decreasing the saturation state (= increasing solubility) of calcium carbonate. Ocean
pH has fallen from an average 8.16–8.05 (Caldeira and Wicket 2003) and models
predict that pH at the ocean surface will continue to fall by an estimated 0.2–0.4
units by the year 2100 (Caldeira and Wicket 2003, 2005, Royal Society 2005, Cao
et al. 2007). These predicted changes in ocean pH are greater, and far more rapid,
than any experienced in the past 300 million years. Again, the Polar Regions will
be particularly affected as the Southern Ocean has among the lowest present-day
CaCO 3 saturation rate of any ocean region, and will therefore be among the first to
become undersaturated (Orr et al. 2005).
So clearly there is an urgent requirement to determine the effect of increased seawater temperatures and acidification on marine life. Not all organisms are affected
equally and while all those studied to date have been shown to be affected, it is
clear that some will adapt and survive (Dupont et al. 2008). We currently know
almost nothing about the genetic mechanisms and genomic basis of this phenoptypic plasticity. It is with this requirement that Polar species, in particular those in
the Antarctic are of great use, for example in the development of biomarkers for
climate change. The advantage of working on Antarctic species is that they are very
thermally sensitive (Peck et al. 2004) and their response is not confounded by pollution, which affects the rest of the planet. Therefore Antarctic organisms offer us
the cleanest signals for the effects of climate change and should be regarded as environmental sentinels. Integrated genomic and functional studies on Polar organisms
are in their infancy (Clark et al. 2004, Peck et al. 2005), but such studies are now