Geoscience Reference
In-Depth Information
age), resulting from re-invasion from lower latitudes and hence little endemism.
So the basic questions are: How did terrestrial ecosystems survive through the
climate extremes of the glacial maxima? Where were the niches? How large do areas
need to be for species to survive many tens of thousands of years, isolated from
other locations?
There is a great deal yet to be done to explain how evolutionary and past
processes formed present day polar biogeography and biodiversity. Knowledge of the
life history of key species is also critical as this will allow determination of their
capacity for adaptation at many levels
-
genomic, biochemical, cellular, physiological,
structural and behavioural
-
in response to the changing biophysical environment.
Ecosystem services
Ecosystems provide goods and services that are fundamental to human wellbeing.
Damage to the environment can seriously affect these
'
ecosystem services
'
and can
have signi
cant economic implications too. The Millennium Ecosystem Assessment
grouped ecosystem services into four dimensions:
Provisioning services, such as food and bio-prospecting for pharmaceutical
products;
Supporting services, such as the draw-down of carbon dioxide from the
atmosphere and the feedbacks on the climate system;
Regulating services, such as the in
uence of and to the climate system, and
Cultural services, such as education, recreation, tourism and aesthetic values.
The ambition of those involved in ecosystem services is to place a value on each
element of the ecosystem. This grand challenge is, however, unlikely to achieve an
international consensus on valuations. Whales are an obvious example; in parts
of the world they would be considered from a conservation viewpoint, but
elsewhere are a highly prized food source.
Over the last 200 years, the Antarctic has been providing food and other
products. Exploitation of whales and seals was carried out extensively in the
nineteenth and twentieth centuries resulting in these animals being driven to near
extinction, while making a few companies and countries economically wealthy.
Penguins were next on the list of species to be culled. In recent years, there has been
further exploitation of the lower trophic levels of
fish, and most recently krill which
are being harvested for the nutraceutical and aquaculture industries.
The size of the krill resource is highly uncertain, estimates range from 133 to
500million tonnes. The harvest in 2009
10 was 0.2million tonnes, which represents
a tiny fraction of the total krill biomass, so in principle the
-
fishery is easily
sustainable. However, the distribution of krill is highly variable with particularly
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