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For the third time this spring, scientists and students of the two
projects CLEOPATRA (“Climate effects on planktonic food quality and trophic transfer in Arctic marginal ice zones”) and “Ecological and ecotoxicological studies of ice amphipods”, both led by Jørgen Berge,
UNIS,
completed an extensive field sampling campaign in one of the most remote
areas in Svalbard. The projects aim at understanding the timing and
linkage of ecological key processes in seasonally ice covered marine
ecosystems. The consequences of changes in light due to retreating and
thinning of Arctic sea ice are of key interest.
Rijpfjorden on Nordaustlandet was chosen as a study site, since it
represents a ‘true’ Arctic fjord. This fjord is open only to the north
and is little influenced by warm Atlantic water masses transported along
the West coast of Spitsbergen. Heavy sea ice prevails until June/July in
this area. In previous years, UNIS cruises have visited this fjord and
taken one transect of samples, usually in August/September. Apart from
these ‘snapshots’ of an early autumn situation, no data about the marine
ecosystem have been available until today. In autumn 2006, a mooring was
placed in Rijpfjorden to provide a continuous year-round data series
about hydrographical and biological features of the fjord that will
serve as important background information for the seasonal study
performed in 2007. In early February 2007, a
weather station
and a
webcam
were established there in order to monitor the meteorological conditions
and ice cover.
During the four field campaigns this spring/summer (March, April, June,
July), biological data about ice algae, phytoplankton, zooplankton, sympagic and benthic amphipods, as well as light profiles and CTD
(Conductivity, Temperature, Density)
measurements are obtained. Further data will be collected during the
autumn cruises in August, September and October. Despite major logistic
challenges and pretty rough weather conditions (at least during the
first stay in March, (see
here), the three expeditions
so far were a great success. Rijpfjorden became completely ice-covered
by land-fast ice during February, and the ice thickness had reached
50-70 cm in early March. The ice was growing further up to 80-100 cm in
mid April, and increased even a little bit more until mid June. Light
conditions, however, were changing greatly during the same period, owing
to changes in the solar angle and snow depth. The biomass of primary
producers differed correspondingly. Zooplankton was found close to the
ice, obviously feeding on ice algae, judging from their green gut and
the absence of algae in the waters below the ice. Their reproduction,
however, seemed to be delayed compared to fjords at the west coast.
Benthic amphipods were also found close to the sea ice showing the
importance of the production in the ice. Despite a lack of multi-year
sea ice in the area, great numbers of truly ice associated amphipods
were found in the inner basin of the fjord.
The ICE EDGE PROGRAMME is a cooperation between The University Centre
in SValbard UNIS, The Norwegian Polar Institute NPI, University in
Tromsø UiT, and University in Oslo UiO. The programme is financed by the
Research Council of Norway (programme NORKLIMA) and Statoil.
(Source: Eva Leu, Postdoc at NPI)
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The camp in Rijpfjorden, Nordaustlandet in April
(Photo: S.Søreide)
Sampling on Rijpfjorden, Nordaustlandet in June
(Photo:
J. Berge) |
