Arctic sea ice contains a substantial amount of living biota of which part is lost through melt and export out of the Arctic Ocean every year. It is unclear how populations can be maintained within the Arctic Ocean. A representative ice inhabitant, the amphipod Apherusa glacialis was previously assumed to spend its entire life in the sea ice habitat, hence being dependent on sea ice to complete ...

The optical chain and logger (OptiCAL) is an autonomous ice-tethered observatory equipped with multiple light sensors for mapping the variation of light with depth. We describe the instrument and present an ensemble calibration for downwelling irradiance E_PAR in [µmolm⁻²s⁻¹]. Results from a long-term deployment in the Arctic Ocean demonstrate that the OptiCAL can ...

As the climate warms, boreal fish species are expected to expand into the Arctic domain. Though water temperature is an important factor driving expansion of aquatic species, other variables may play a critical role in restricting those movements. Continuous darkness during the Arctic polar night has been suggested to impair foraging in visually searching boreal fish and may thus limit their northward ...

Knowledge of environmental preferences of the key planktonic species, such as Calanus copepods in the Arctic, is crucial to understand ecosystem function and its future under climate change. Here, we assessed the environmental conditions influencing the development stages of Atlantic Calanus finmarchicus and Arctic Calanus glacialis, and we quantified the extent to which their niches overlap by ...

Before man hunted the large baleen whales to near extinction by the end of the nineteenth century, Arctic ecosystems were strongly influenced by these large predators. Their main prey were zooplankton, among which the calanoid copepod species of the genus Calanus, long considered key elements of polar marine ecosystems, are particularly abundant. These herbivorous zooplankters display a range of ...

Recent discoveries of high levels of biological activity in the Arctic marine ecosystems during the polar night raise questions regarding the ecophysiology of the pelagic postlarval daubed shanny Leptoclinus maculatus. Of special interest is the composition of the lipid sac—a unique feature not found in other Arctic fishes. Analysis of the fatty acid content of major classes of lipids as membrane—total ...

Zooplankton vertical migration enhances the efficiency of the ocean biological pump by translocating carbon (C) and nitrogen (N) below the mixed layer through respiration and excretion at depth. We measured C and N active transport due to diel vertical migration (DVM) in a Svalbard fjord at 79°N. Multifrequency analysis of backscatter data from an Acoustic Zooplankton Fish Profiler moored from January ...

Climate changes in the Arctic are predicted to alter distributions of marine species. However, such changes are difficult to quantify because information on present species distribution and the genetic variation within species is lacking or poorly examined. Blue mussels, Mytilus spp., are ecosystem engineers in the coastal zone globally. To improve knowledge of distribution and genetic structure of ...

The increasing human presence in the Arctic shelf seas, with the expansion of oil and gas industries and maritime shipping, poses a risk for Arctic marine organisms such as the key species polar cod (<i>Boreogadus saida</i>). The impact of dietary crude oil on growth and metabolism of polar cod was investigated in the early spring (March–April) when individuals are expected to be in a vulnerable ...

Current knowledge of the Arctic marine ecosystem is based primarily on studies performed during the polar day on the pelagic and benthic realms. Both the polar night and the hyperbenthic layer remain as substantial knowledge gaps in our understanding of the marine system at high latitudes. This study investigated the hyperbenthic food web in Kongsfjord, a high-latitude, ice-free fjord, in September ...