Doreen Kohlbach

Norwegian Polar Institute

To better predict ecological consequences of changing Arctic sea ice environments, we aimed to quantify the contribution of ice algae-produced carbon (αIce) to pelagic food webs in the central Arctic Ocean. Eight abundant under-ice fauna species were submitted to fatty acid (FA) analysis, bulk stable isotope analysis (BSIA) of nitrogen (δ15N) and c...

We investigated the role of sea ice-derived carbon in the food web of Eclipse Sound, Canadian Arctic during the spring ice-covered season to understand the potential ecological impact of changes to the sea-ice habitat. Chlorophyll (chl) a concentrations in the bottom of sea ice (438.2 ± 154.2 µg l-1, 19.8 ± 6.6 mg m-2) were more than two orders of...

Ice algae are critical components to the lipid-driven Arctic marine food web, particularly early in the spring. As little is known about these communities in multiyear ice (MYI), we aimed to provide a baseline of fatty acid (FA) and stable isotope signatures of sea-ice communities in MYI from the Lincoln Sea and compare these biomarkers to first-ye...

We investigated diets of 24 Barents Sea zooplankton taxa to understand pelagic food-web processes during late summer, including the importance of sea ice algae-produced carbon. This was achieved by combining insights derived from multiple and complementary trophic marker approaches to construct individual aspects of feeding. Specifically, we determ...

The Barents Sea is a hotspot for environmental change due to its rapid warming, and information on dietary preferences of zooplankton is crucial to better understand the impacts of these changes on food-web dynamics. We combined lipid-based trophic marker approaches, namely analysis of fatty acids (FAs), highly branched isoprenoids (HBIs) and stero...

Sea ice primary production is considered a valuable energy source for Arctic marine food webs, yet the extent remains unclear through existing methods. Here we quantify ice algal carbon signatures using unique lipid biomarkers in over 2300 samples from 155 species including invertebrates, fish, seabirds, and marine mammals collected across the Arct...

Anthropogenic climate change is causing changes to the Arctic sea-ice system with implications for the magnitude and timing of Arctic pelagic and ice-associated (sympagic) primary production that influences food web interactions. Ringed seals (Pusa hispida) are generalist predators that, as a species experience vastly different icescapes from low t...

The rapid rate of climate change in the Arctic is causing broad-scale changes to the physical environment and biological communities. Characterizing the foraging ecology and habitat use of Arctic marine top predators of high ecological and cultural significance is essential to our understanding of their vulnerability to ecosystem change, especially...

The spring season was the target for the Nansen Legacy cruise organized in late April and first half of May 2021 following the transect defined for this series of cruises to capture the variations of the year sampling physical, biological and chemical conditions in the ice and the sea. The transect went through both open water and ice. Seven proces...

Microalgae growing within and attached to the bottom of Arctic sea ice (sympagic algae) can serve as a nutritious food resource for animals inhabiting the sea-ice water interface (under-ice fauna), particularly during the bottom ice-algal bloom in spring. As a consequence, under-ice fauna is likely impacted by sea-ice decline and changes in ice-alg...

Allometric relationships between body properties of animals are useful for a wide variety of purposes, such as estimation of biomass, growth, population structure, bioenergetic modelling and carbon flux studies. This study summarizes allometric relationships of zooplankton and nekton species that play major roles in polar marine food webs. Measurem...

Sea ice is an important habitat for many organisms, from the microscopic up to large mammals like seals and polar bears. Small animals called zooplankton can feed directly on microscopic plant-like sea-ice algae. Larger animals, such as fish can, in turn, feed on zooplankton, seals feed on fish and larger zooplankton, and polar bears hunt seals. In...

Overview and synthesis of the present state of the Arctic Seas of Canada

Specific case studies in support of the main technical report 3344

Changes to the sea-ice habitat due to climate warming and potentially increased shipping activities in the Canadian Archipelago might not only have dramatic consequences for the ice-associated ecosystem, but will also have a large impact on pelagic and benthic food web dynamics due to the close connectivity between these ecosystems. Changes at the...

In the Arctic Ocean, sea-ice decline will significantly change the structure of biological communities. At the same time, changing nutrient dynamics can have similarly strong and potentially interacting effects. To investigate the response of the taxonomic and trophic structure of planktonic and ice-associated communities to varying sea-ice propert...

Sea ice algae can constitute an important carbon source for high-Antarctic euphausiids during winter. To quantify the importance of this ‘sympagic carbon’ during summer, the three most abundant Antarctic euphausiids, Euphausia superba, E. crystallorophias, and Thysanoessa macrura, collected off the Filchner Ice Shelf, were analyzed regarding their...

How the abundant pelagic life of the Southern Ocean survives winter darkness, when the sea is covered by pack ice and phytoplankton production is nearly zero, is poorly understood. Ice-associated ("sympagic") microalgae could serve as a high-quality carbon source during winter, but their significance in the food web is so far unquantified. To bette...

Antarctic krill Euphausia superba is an ecological key species in the Southern Ocean and a major fisheries resource. The winter survival of age class 0 (AC0) krill is susceptible to changes in the sea-ice environment due to their association with sea ice and their need to feed during their first winter. However, our understanding of their overwinte...

Antarctic krill Euphausia superba (" krill ") constitute a fundamental food source for Antarctic seabirds and mammals, and a globally important fisheries resource. The future resilience of krill to climate change depends critically on the winter survival of young krill. To survive periods of extremely low production by pelagic algae during winter,...

The polar cod (Boreogadus saida) is considered an ecological key species, because it reaches high stock biomasses and constitutes an important carbon source for seabirds and marine mammals in high-Arctic ecosystems. Young polar cod (1-2 years) are often associated with the underside of sea ice. To evaluate the impact of changing Arctic sea ice habi...

Polar cod (Boreogadus saida) is an important food source for top predators and the most abundant fish underneath the Arctic pack ice. The diet of polar cod was investigated using fish caught directly underneath the sea ice, in order to look at the use of food sources that are provided by the sea-ice habitat. The diet was compared between polar cod...

Even creatures living many metres below the Arctic Ocean's surface rely on algae that grow in sea ice and so, like those living near the surface, may feel the negative effects of shrinking ice.

Bergen

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EMBS Symposium, September 2012

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The condition, survival and recruitment of Antarctic krill (Euphausia superba) depend to a large extent on overwintering success. In winter, much of the krill habitat is ice covered. Models suggest that sea ice properties during the late winter – spring period have the largest effect on recruitment. During this period, larval and juvenile krill sur...

Atlantic mackerel (Scomber scombrus L.) is a widely distributed commercially important pelagic species. Little is known about the stock structure of this species, but it is thought to be undergoing a range extension due to environmental changes. Knowledge of the stock structure under these changing conditions is fundamental for effective management...