Description of task
WP5. task 4: Impacts on 1) CO2 cycle and phytoplankton production, and 2) Marine Ecosystems
Subtask 1: CO2 cycle and phytoplankton production
This sub task contributes to the study of the impact of changing sea ice cover on air-sea CO2 flux. Air-sea flux of CO2 is impacted by a number of processes that likely will be affected by a changing seasonal sea ice cover. The objective is to evaluate the effect of a changing sea ice cover on air-sea CO2 flux.
During the first 18 months, historic data will be used to compute the fCO2 field in the surface waters of the Arctic Ocean. Based on existing carbon system and hydrographic data (T, S, O2 and nutrients) model computations of different sophistication levels will be utilized to compute surface water fCO2 and potential sequestration of carbon under different sea ice conditions scenarios.
Subtask 2: Climate impact on marine ecosystems
This subtask contributes to the study of the impacts of changing conditions in the Arctic Ocean and climate on the marine ecosystem. For certain processes, the ocean responds more or less passively to atmospheric changes. In other cases, feedback mechanisms link ocean and the atmosphere, and it is clear that the ocean plays a very important role in climate change and variability. The Arctic Climate Impact Assessment (ACIA), concluded that there are gaps in knowledge on the impact of changing conditions in the Arctic Ocean and climate on the marine ecosystem. Large, long-lived Arctic species tend to have very stable populations, so even dramatic changes in juvenile survivorship may not be easily detected for a considerable period of time. At the other end of the size range of organisms, natural variation in population size of phytoplankton is generally large and can mask detection of longer-term trends in abundance. Thus, long-term data series are essential to monitor climate-induced change in Arctic marine ecosystems.
The objective of this subtask is to quantify the changes in the marine ecosystem, particularly in fishery resources, including distribution, production and biodiversity due to changing conditions in the Arctic Ocean and climate (salinity, sea ice, stratification).
During the first 18 months, the research will focus on some of the knowledge gaps related to impacts on marine systems as identified by ACIA. The consequences of the documented dramatic warming of the 1920s and 1930s and data from the time periods of 1979-1981 and 2003-2005 (WP4) will be analysed and compared to the response to the current warming. Given that the amplitude of the warming is of the same order of magnitude in both periods, comparing and contrasting the biological responses to these two events will provide insights into climate-induced responses as well as into possible future changes. Finally we will use the outcome of the other WP's to estimate the timing of reproduction for many species in relation to that of their prey. How Arctic specialist species will respond to possible increased competition from more opportunistic, generalist species in a warmer Arctic is unknown. How the timing and location of the production and spawning of most species might change in response to changes in the sea ice is unclear, as is the extent of the match-mismatch with their prey and predators.
