RESEARCH
The Arctic environment is unique and rich in biodiversity and home to many species of global importance. At the same time, the region is very sensitive to disturbances and is strongly affected by the ongoing climate change together with increasing commercial activities. Climate change is faster in the Arctic than in any other part of the world and the effects are clear. In the summer of 2012, the sea ice extent experienced a record low while the average temperature in the Arctic has increased twice as much as the global average temperature over the past 100 years. This already now exposes communities and ecosystems under great strain. The rapid effects in the Arctic can also affect the global climate.
The Arctic Ocean constitutes only three percent of the Earth's surface and one percent of global ocean volume. Despite this, the Arctic Ocean receives ten percent of global river runoff. Large amounts of organic material (carbon) are transported by the rivers to the shallow shelf seas and sequentially out into the deep basins. In the shelf seas, a large part of the organic carbon is remineralized by microbial processes to carbon dioxide, which is either degassed to atmosphere or transported out to the previous ice-covered deep basins.
The carbon cycle in the Arctic Ocean is an important component of the marine ecosystem and is, due to its interaction with atmospheric carbon dioxide, of fundamental importance for the Earth's climate. Currently, the reduction in emissions of long-lived climate gases, primarily carbon dioxide, may be the most important measure to limit the warming of the Arctic. It is reported that the Arctic Ocean's uptake of carbon dioxide from the atmosphere makes up ten percent of the global uptake from the atmosphere, but this estimate is uncertain. There is also great uncertainty about whether the Arctic Ocean will be a sink or source of carbon dioxide in the ice-free conditions during the summer months. The outcome will largely depend on future changes in primary production, where phytoplankton takes up and converts carbon dioxide into organic carbon through photosynthesis. Subsequent vertical export of the carbon from of the surface layer, the biological pump, is directly linked to net production.
Most studies of primary production and net community production in the Arctic Ocean has focused on the productive shelf seas. This is partly because the central Arctic is often inaccessible at the beginning of the productive season. Current estimates of the annual and seasonal primary and net production is low in the central region compared to the productive shelf seas.
"Fluxes of carbon dioxode and net community production in a changing Arctic Ocean using novel high-resolution methods"
The aim of this project is to further increase our understanding of the carbon cycle in a warmer Arctic Ocean with decreasing sea ice cover. Currently, it is uncertain whether the Arctic Ocean will be a sink or source of carbon dioxide in the ice-free conditions during the summer months. The outcome depends on future changes in the primary and biological net production, which may vary between regions. The project will focus on the spatial and temporal variability of carbon fluxes and net community production by applying novel high-resolution continuous methods during international trans-Arctic field studies onboard research icebreakers. Please see additional information in the project-related links below:
CURRENT
RYDER 2019
MOSAiC 2019/20
SYNOPTIC ARCTIC SURVEY (SAS) 2020
PREVIOUS
TRANSARC (PS78) 2011
SWERUS-C3 2014
TRANSARC II (PS94) 2015
GRIFF (PS100) 2016
OTHER RELEVANT LINKS
GEOTRACES
CASSAR LAB - Duke University
"Chemical speciation and the marine carbonate system"
Another part of my research focuses on the development and application of quantitative models for seawater chemistry, e.g., specific ion interaction models coupled to humic models in order to study the effect of organic alkalinity on the marine carbonate system. It is well known that the reactivity of the elements in sea water depends on the chemical species available. The chemical speciation of ions and their interaction with organic materials such as humic substances in seawater may be very important for the marine carbonate system, especially in coastal waters. Although equilibrium conditions do not apply everywhere, equilibrium calculations constitute the starting point for an understanding of the basic chemistry of the elements in the sea.
TEACHING (2018-)
TEACHING (2009-2014)
- KEM011 - Inorganic Chemistry
- KEM070 - Analytical Chemistry 1
- KEM080 - Analytical Chemistry 2
- KER210 - Analytical Pharmaceutical Chemistry
- MAR102 - Marine Sciences 1
- MAR106 - Marine Sciences 2
- KEM490 - Environmental Chemistry
