Glacial Melt Endangers Ecosystems
Hereon Investigates Water in Arctic Fjords – Global Warming Has Drastic Impacts Here Too
The Arctic regions are particularly vulnerable to climate change. However, comprehensive scientific information about environmental changes in these areas remains lacking. Researchers from the Helmholtz-Zentrum Hereon have now investigated inorganic carbon parameters, nutrients, and trace elements in fjord systems. The findings: The melting glacial ice alters the chemical composition of the water in fjords, destabilizing ecosystems. The study was recently published in the journal Global Biogeochemical Cycles.
The case study is based on an expedition to Kongsfjorden on the west coast of Svalbard and the German-French research station Arctic Research Base Ny-Ålesund (AWIPEV) located there. Researcher Claudia Schmidt from the Hereon Institute of Carbon Cycles studied how glacial freshwater runoff affects the total concentration of nutrients, trace elements, and carbon parameters in the Arctic fjord. She collected water samples along the fjord axis and from rivers, observing biogeochemical changes in coastal waters.
The freshwater inflow creates a barrier layer on the highly saline fjord water, altering the circulation of water masses as well as the distribution of nutrients and trace elements. One potential consequence is a reduction in phytoplankton, which forms the basis of the marine food chain. Its availability impacts many ocean organisms, biodiversity, and significantly, the sequestration of CO₂. A potential decline in phytoplankton would reduce the uptake and storage of the greenhouse gas CO₂. (Source: Hereon Press Release)
Read the complete Hereon Press Release:
==> Glacial Melt Endangers Ecosystems
==> Website ECOTIP
Schmidt, C.E., Pröfrock, D., Steinhoefel, G., Stichel, T., Mears, C., Wehrmann, L.M., & Thomas, H. (2025): The contrasting role of marine- and land-terminating glaciers on biogeochemical cycles in Kongsfjorden, Svalbard. Global Biogeochemical Cycles, 39, doi:10.1029/2023GB008087
Abstract:
This case study of Kongsfjorden, western coastal Svalbard, provides insights on how freshwater runoff from marine- and land-terminating glaciers influences the biogeochemical cycles and distribution patterns of carbon, nutrients, and trace elements in an Arctic fjord system. We collected samples from the water column at stations along the fjord axis and proglacial river catchments, and analyzed concentrations of dissolved trace elements, together with dissolved nutrients, as well as alkalinity and dissolved inorganic carbon. Statistical tools were applied to identify and quantify biogeochemical processes within the fjord that govern the constituent distributions. Our results suggest that the glacier type affects nutrient availability and, therefore, primary production. Glacial discharge from both marine-terminating glaciers and riverine discharge from land-terminating glaciers are important sources of dissolved trace elements (dAl, dMn, dCo, dNi, dCu, and dPb) that are involved in biological and scavenging processes within marine systems. We identified benthic fluxes across the sediment-water interface to supply fjord waters with silicate, dFe, dCu, and dZn. Our data show that intensive carbonate weathering in proglacial catchments supplies fjord waters with additional dissolved carbonates and, therefore, attenuates reduced buffering capacities caused by glacial runoff. Our study provides valuable insight into biogeochemical processes and carbon cycling within a climate-sensitive, high-latitude fjord region, which may help predict Arctic ecosystem changes in the future.
Niedzwiedz, S., Schmidt, C., Yang, Y., Burgunter-Delamare, B., Andersen, S., Hildebrandt, L., Pröfrock, D., Thomas, H., Zhang, R., Damsgård, B., & Bischof, K. (2024): Run-off impacts on Arctic kelp holobionts have strong implications on ecosystem functioning and bioeconomy. Sci Rep 14, 30506, doi:10.1038/s41598-024-82287-w
Abstract:
Kelps (Laminariales, Phaeophyceae) are foundation species along Arctic rocky shores, providing the basis for complex ecosystems and supporting a high secondary production. Due to ongoing climate change glacial and terrestrial run-off are currently accelerating, drastically changing physical and chemical water column parameters, e.g., water transparency for photosynthetically active radiation or dissolved concentrations of (harmful) elements. We investigated the performance and functioning of Arctic kelp holobionts in response to run-off gradients, with a focus on the effect of altered element concentrations in the water column. We found that the kelp Saccharina latissima accumulates harmful elements (e.g., cadmium, mercury) originating from coastal run-off. As kelps are at the basis of the food web, this might lead to biomagnification, with potential consequences for high-latitude kelp maricultures. In contrast, the high biosorption potential of kelps might be advantageous in monitoring environmental pollution or potentially extracting dissolved rare earth elements. Further, we found that the relative abundances of several kelp-associated microbial taxa significantly responded to increasing run-off influence, changing the kelps functioning in the ecosystem, e.g., the holobionts nutritional value and elemental cycling. The responses of kelp holobionts to environmental changes imply cascading ecological and economic consequences for Arctic kelp ecosystems in future climate change scenarios.
