Geoscience Reference
In-Depth Information
Changes in the atmospheric forcing lead to shifts in position of fronts separating Pa-
cific and Atlantic waters, with associated alterations in the circulation in the Arctic Bas-
in. This has potential implications for fish production, due to changes in nutrient supplies
to the euphotic zone and changes in primary production. Changes in light conditions will
also influence this. Major circulation alterations and changes in water column properties
are driven by changes in advection, for instance transport of water of Atlantic origin north-
wards into the basin. These advective processes also influence the distribution of biologic-
al species including phytoplankton and zooplankton, and invasion of new species coupled
with the regional warming. Invasion of new species is documented in parts of the Arctic
Low levels of oxygen in poorly ventilated subsurface waters are well documented in
some sub-Arctic regions, and concern for oxygen decrease and hypoxia in ocean waters
around northern North America is increasing. However, the Arctic Ocean and bordering
In the Arctic, changes occur relatively fast in comparison with other regions, evid-
enced by observations. These also bring out the significance of the linkages between
ocean basins and the interdependencies. Observations and modelling simulations show that
changes in the Arctic will have an impact on the global thermohaline over-turning circu-
lation (the great conveyor belt) and on properties of downstream ocean basins. Changes
in the physical environment of the Arctic Ocean are affecting the marine ecosystem.
However, quantification of these effects remains elusive, for instance, whether organic pro-
duction will increase or decrease in conditions of reduced ice cover. This underlines the
need to understand the mechanisms and causal links that drive a change, in addition to ob-
serving and describing it. However, the vulnerability of the Arctic to climate change and
several different potential human impacts is a cause for increasing concern.
Concern for the Antarctic was displayed through the initiation, after IGY
(1957-1958), of the Antarctic Treaty of December 1959. Its aim is 'in the interests of all
mankind that Antarctica shall continue forever to be used exclusively forpeaceful purposes
and shall not become the object of international discord'. This can be understood as an
