Ecosystem Studies of Subarctic and Arctic Regions

Project Description
Proposal URL:

ESSAR addresses how climate variability and change affects the marine
ecosystems of the polar (Subarctic and Arctic) seas and their
sustainability. To provide accurate projections on the impact of
climate warming on these ecosystems requires improved knowledge of its
components and their linkages. Because of the complexity of the
interactions, accurate predictions of what will happen to individual
species requires knowledge on key life-history traits and of what will
happen to the ecosystem as a whole, as species do not function
separately from their ecosystem. ESSAR, therefore, encompasses
retrospective and field studies on physics, plankton, benthos, fish
and shellfish, marine mammals, sea birds and humans. The field studies
will be carried out in the Atlantic, Pacific and Arctic Oceans during
2007-2008. The data gathered will be used, together with bio-physical
models, to make quantifiable predictions of the effects of both
climate variability and long-term climate change on arctic polar
marine ecosystems.

To understand the effects of climate variability and change on marine
ecosystems we first must document what changes have occurred in the
physical oceanography, as well as understand the driving forces behind
them. ESSAR will therefore assemble historical data on the physical
oceanography and collect new data to fill in critical gaps in our
knowledge, such as moored current measurements in the Davis
Strait-Hudson Strait-Labrador Shelf region and in the northern Barents
Sea between Svalbard and Franz Josef Land. With recent reductions in
sea ice and predictions of much greater reductions, ESSAR will address
the effects of changes in sea ice on various parts of the
ecosystem. Results from past and present studies will be assembled to
document distributional shifts of several marine species from plankton
to marine mammals and seabirds. Also, new field studies in the
Subarctic of both the Pacific and Atlantic, and in the Arctic, will
examine the relationship between thermal heating of the waters and
changes in ice coverage, including various feedback
mechanisms. Nutrient, chlorophyll, ice algae, chemical tracers,
phytoplankton and zooplankton measurements will determine the effect
of ice decline on biological processes. An important change following
the reduction in ice will be an increase in light levels. Detailed
studies of the role of light levels on primary and secondary
production along the latitudinal gradients from 45°N to near the pole
will determine how light levels and day duration modify ecosystem
function. The effects of water mass transformations on plankton
production will be compared and contrasted with the effects of sea ice
and light to determine their relative importance. Our understanding of
the sources and variability in zooplankton and their role in the food
chain varies regionally. Data are relatively scarce in the Labrador
Sea, therefore, under ESSAR, concentrated zooplankton studies,
especially on Calanus finmarchicus, will be carried out. Field-based
studies will also focus on the effects of the physical variability on
the energy flow through Arctic and Subarctic marine food webs from
plankton through fish to marine mammals and seabirds, e.g. in the
Barents Sea, the Norwegian Sea, Lancaster Sound and Hudson Bay. From
the human perspective, certain marine species are more important than
others because of their commercial or subsistence values. The physical
environment also influences these species, but our understanding of
the mechanisms is limited. One of the most important commercial
species in the Northwest Atlantic is shrimp (Pandulus borealis). As
part of ESSAR, there will be studies of the role of physical
oceanography and biological production cycles in recruitment,
abundance and distribution of shrimp in Davis Strait, off West
Greenland, on the Labrador Shelf and in the Gulf of St. Lawrence. At
the upper ends of the food web, marine mammals and seabirds will be
affected by changes in the lower ends. Studies will determine the role
of changes in sea ice and warming waters on marine mammal fitness,
including whales, walruses, seals and polar bears. Seabirds respond
relatively quickly to changes in their prey and often can be monitored
relatively easily compared to their prey in the marine
environment. ESSAR, through the Circumpolar Seabird Group (CBird) and
the members of Conservation of Arctic Flora and Fauna (CAFF), will
monitor how changes in productivity of Arctic and Sub-Arctic seas
affect circumpolar seabird populations. Seabird diet studies also will
be carried out and compared to similar studies conducted in the 1970s
and 1980s as a means of detecting if and how the marine ecosystem has
changed. As well, detailed studies in the smaller region of Svalbard
will be carried out to investigate the changes in seabird community
structure as a function of temperature and zooplankton. The effects of
these changes to the bird community on the terrestrial ecosystem
through the guano deposited back on land will also be part of this
study. Finally, comparisons between the various geographic regions to
provide additional insights will be an important component of ESSAR.