We conducted an intensive program of observational and experimental fieldwork on the Ice Chaser cruise, which generated a vast array of samples. These samples will be fully analysed when they are returned to labs in the UK, France and Norway. (Many samples are still in freezers onboard ship in the Arctic, waiting for the James Clark Ross to return to the UK in mid September.) We also retrieved a set of instruments from Rijpfjorden in the remote and rarely visited north-east corner of Svalbard. These instruments had collected unique long-term data on the Arctic marine environment and their retrieval was a significant achievement. (No other ships have been able to break into the area this season.)

Oceanographic research takes time and our Arctic fieldwork was just the first step towards achieving our overall research objective. It will take several months to analyse the expedition’s samples and the full story of what we have discovered will be competed in 2009. Our findings will be then used to refine numerical models which simulate the effect of climate change on the Arctic marine ecosystem and carbon flow.

Some observations and analyses were performed on the ship and the results from these are summarised below. These preliminary results give us only a partial insight into the functioning of the ecosystem and the carbon cycle in waters north of Svalbard. They should therefore be interpreted with caution. They also represent only a small fraction of the expedition’s eventual output.

Our Findings 

The oceanographic conditions we encountered north of Svalbard were colder than expected with extensive ice cover. These cold conditions were a local feature produced by northerly winds forcing Arctic sea ice south onto the north coast of Svalbard. The Arctic as a whole has experienced extensive sea ice melt this summer, with ice retreat the second lowest on record (with a few weeks of melt still to go), resulting in thinner pack ice. (See National Snow and Ice Data Center) This thinner sea ice is more mobile and some of it was blown into our study area, maintaining local ice cover and cold conditions longer into the summer than expected.

The marine ecosystem at our study sites seemed to be characterised by typical Arctic species (the full taxonomic analysis of our samples will confirm if this was the case or whether invasive warmer water species were present). The unique cold conditions we encountered therefore enabled us to generate valuable baseline data on the functioning of a true cold water Arctic ecosystem. This establishes a standard against which we will compare future observations from the region, enabling us to detect ecosystem change brought about by warming in the Arctic.

Phytoplankton were observed in the water column with peak abundances recorded at depths characterised by very low light levels (<1% surface solar radiation). The phytoplankton were actively growing, although relatively slowly. Much of the carbon taken in by the phytoplankton was being released back out into the seawater as dissolved compounds (this behaviour is normal for late summer populations of Arctic phytoplankton but we still don’t know exactly why they do it). Very little phytoplankton carbon was being incorporated into calcareous phytoplankton shells.

High concentrations of recycled nutrients were observed in deeper waters, just below the depths where phytoplankton were growing. It is likely that the phytoplankton were growing best at depths where they were supplied simultaneously with light (albeit at low levels) from above and recycled nutrients from below.

An abundantand active bacterial community was observed in the water column suggesting that considerable amounts of energy, carbon and nutrients were being recycled by the microbial community (rather than being transferred up the food web to larger organisms). This bacterial community was not, however, using the dissolved carbon compounds released by the phytoplankton. We do not yet know why. We also do not yet know what the bacteria were consuming nor what happened to the abundant dissolved carbon compounds released by the phytoplankton. Full sample analysis should help answer these questions.

Healthy populations of large herbivorous zooplankton were found in deep waters at our study sites. These Arctic species had stores of high energy lipids accumulated whilst feeding on phytoplankton earlier this summer, and had entered winter “hibernation”. This suggests that their food supply must have been active and abundant underneath the sea ice earlier in the year, despite low light levels encountered under the sea ice. It also suggests that a substantial quantity of energy and carbon had been transferred up the food web to larger organisms during spring/early summer.

Experiments on the microscopic water column organisms showed that an increase in water temperature may lead to a decrease in phytoplankton growth. Full sample analysis should reveal why this happened and whether a similar effect is likely to occur when Arctic seas warm.

The sea-bed Lander experiments showed that carbon and nutrients were recycled faster at higher sea-bed temperatures. Again, full sample analysis should reveal why this happened and whether a similar effect is likely to occur when Arctic seas warm.