From Source to Sink – trace metal cycles in a changing environment
A team of four scientists led by AWI headed to Svalbard in July 2020 to uncover the secrets of the biogeochemical cycle of trace metals in the Arctic.
Retreating glaciers in the Arctic uncover areas that have been previously hidden underneath ice sheets. These areas often consist of very reactive sediments that have the potential to release significant amounts of trace metals into melt water which is then transported into the ocean. Trace metals are elements that occur in only small amounts in a given volume of natural water, usually less than 1 ppm (parts per million) and as low as 1 ppt (parts per trillion).
These elements are of great importance for marine life as some of them are needed for algae growth whereas others can be used as tracers for environmental changes. Detailed studies of such trace metals are therefore vital to understand the biogeochemical cycle of elements within the Earth system.
In July this year a team of two members of the AWI section Marine Geochemistry, Dr. Torben Stichel and Dr. Grit Steinhöfel and two colleagues from the Helmholtz Centre Geesthacht (HZG), Claudia Schmidt (PhD student) and Chantal Mears (MSc student) headed to the French-German AWIPEV station in Ny Ålesund on Svalbard to collect water and sediment samples to better understand the biogeochemical cycle of trace metals in Arctic regions that are undergoing profound environmental change.
The aim of the research expedition was to collect samples during the peak melt period to find out if the proglacial sediments in the area provide a source for the trace metal budget in the adjacent Kongsfjorden. The trace metals of interest are indicators of weathering intensities (lithium and hafnium isotopes), origin (neodymium isotopes and rare earth elements), but also potential pollutants (e.g. copper). The first two groups of elements are important tracers for changing geochemical conditions. Pollutants and their impact on ecosystems is also the topic of the recently funded EU project ECOTIP lead by HZG.
Travel restrictions allowed entrance to Svalbard, then one of the few places on earth without a single COVID-19 case, only after ten days of self-isolation in mainland Norway close to the port of entry. The quarantine time was used by the team to further prepare the field trip as they met in person only then for the first time after several organisational video conferences. Originally, the expedition was planned to consist of a group of scientists from AWI and Stony Brook University (USA), who unfortunately had to cancel due to Corona caused travel restrictions. Therefore, the team was completed by the HZG scientists on a very short notice. “It was too bad that Laura Wehrmann and her PhD student could not join this year, but we will share collected samples and continue our collaboration. It was great that colleagues from HZG could fill the gap to support field work and additional contribute their expertise to the project”, said AWI scientist Dr. Steinhöfel.
In Ny Ålesund, the researchers used the research facilities provided by AWIPEV research station, including boats, polar gear and equipment for polar bear protection. The village of Ny Ålesund consists of an assembly of international research stations from India, Italy, Norway, South Korea, Great Britain and the Netherlands and has a population ranging from 30 inhabitants in winter to 170 in summer. The village is managed by a Norwegian contractor (Kingsbay A/S), which is responsible for the infrastructure for food supply and general maintenance, but also additional lodging as well research facilities, equipment and vessels.
The samples were collected either from melt water streams, draining from the land terminating glaciers into the Kongsfjord or during short trips on the AWIPEV’s research boats from seawater.
During sample collection, temperature, salinity and pH was recorded as well, which aid as important meta-data for trace metal biogeochemical cycles. In addition to water, sediment samples were also collected to acquire additional information from the presumed sources at the glacier front to the sink in marine sediments.
“The expedition was a great success both in terms of science but also for the strengthened collaboration between AWI and HZG” said expedition team leader Dr. Stichel. “From this collection we expect to gain critical information on the elemental cycle when retreating glaciers expose fresh sediments”.
Future campaigns are planned within the new research program in PoF IV that, among others, strengthens joint activities of AWI and HZG in polar coastal areas. Those campaigns will be focused on the seasonality and the long term influence on the carbon cycle to further assess the vulnerability of the Arctic during climate change.
