The ecophysiology of under-ice fauna

Aarset, A. V.

doi:10.1111/j.1751-8369.1991.tb00656.x

Cited by 23 publications

(5 citation statements)

References 71 publications

(58 reference statements)

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“…Temperatures exceeding the normal variability in the natural habitat were tolerated for exposure times of more than 30 min. These findings correspond to those of Aarset (1991), who reported that short-term exposure to 10°C was not lethal in A. glacialis.…”

Section: Crypsis and Thermoregulationsupporting

confidence: 91%

The adaptive significance of chromatophores in the Arctic under-ice amphipod Apherusa glacialis

et al. 2010

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Solar radiation is a crucial factor governing biological processes in polar habitats. Containing harmful ultraviolet radiation (UVR), it can pose a threat for organisms inhabiting surface waters of polar oceans. The present study investigated the physiological color change in the obligate sympagic amphipod Apherusa glacialis mediated by red-brown chromatophores, which cover the body and internal organs of the species. Short-term experimental exposure to photosynthetic active radiation (PAR) led to pigment dispersal in the chromatophores, resulting in darkening of the animal. Irradiation in the PAR range (400-700 nm) was identified as the main trigger with high light intensities evoking marked responses within 15 min. After exposure to high PAR, darkness led to a slow aggregation of pigments in the cell center after 24 h. Experiments revealed no statistically significant change in coloration of the animal when exposed to different background colors nor UV radiation. Our results point to a doseand time-dependent photoprotective role of chromatophores in the amphipod, presuming a shielding effect from harmful radiation in a dispersed state. The reversible nature of the physiological color change enables the species to adapt dynamically to prevailing light conditions and thereby minimize the cost of increased conspicuousness toward visually hunting predators.

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Section: Crypsis and Thermoregulationsupporting

confidence: 91%

The adaptive significance of chromatophores in the Arctic under-ice amphipod Apherusa glacialis

et al. 2010

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“…Meiofaunal organisms living in the melting ice have osmoregulatory mechanisms allowing them to survive across a wide spectrum of salinities (Aarset 1991;Friedrich 1997;Gradinger 2002;Kiko et al 2009). The respiration rates of some Arctic amphipod species increase 2-3 times at salinities below 15 PSU and the amphipod Gammarus wilkitzkii is able to maintain high concentrations of inorganic ions in the haemolymph at salinities down to 5 PSU (Aarset 1991;Gradinger 2001). When salinity decreases drastically, freshwater taxa dominate (Gradinger et al 2010).…”

Section: Adaptation Of Meiofauna To Polar Conditionsmentioning

confidence: 99%

Characteristics of meiofauna in extreme marine ecosystems: a review

et al. 2017

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Extreme marine environments cover more than 50% of the Earth's surface and offer many opportunities for investigating the biological responses and adaptations of organisms to stressful life conditions. Extreme marine environments are sometimes associated with ephemeral and unstable ecosystems, but can host abundant, often endemic and welladapted meiofaunal species. In this review, we present an integrated view of the biodiversity, ecology and physiological responses of marine meiofauna inhabiting several extreme marine environments (mangroves, submarine caves, Polar ecosystems, hypersaline areas, hypoxic/anoxic environments, hydrothermal vents, cold seeps, carcasses/sunken woods, deep-sea canyons, deep hypersaline anoxic basins [DHABs] and hadal zones). Foraminiferans, nematodes and copepods are abundant in almost all of these habitats and are dominant in deep-sea ecosystems. The presence and dominance of some other taxa that are normally less common may be typical of certain extreme conditions. Kinorhynchs are particularly well adapted to cold seeps and other environments that experience drastic changes in salinity, rotifers are well represented in polar ecosystems and loriciferans seem to be the only metazoan able to survive multiple stressors in DHABs. As well as natural processes, human activities may generate stressful conditions, including deoxygenation, acidification and rises in temperature. The behaviour and physiology of different meiofaunal taxa, such as some foraminiferans, nematode and copepod species, can provide vital information on how organisms may respond to these challenges and can provide a warning signal of anthropogenic impacts. From an evolutionary perspective, the discovery of new meiofauna taxa from extreme environments very often sheds light on phylogenetic relationships, while understanding how meiofaunal organisms are able to survive or even flourish in these conditions can explain evolutionary pathways. Finally, there are multiple potential economic benefits to be gained from ecological, biological, physiological and evolutionary studies of meiofauna in extreme environments. Despite all the advantages offered by meiofauna studies from extreme environments, there is still an urgent need to foster meiofauna research in terms of composition, ecology, biology and physiology focusing on extreme environments.

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“…Metabolic rates, e.g. ingestion and respiration, of under-ice amphipods are generally low, due to their energy-saving lifestyle attached to the underside of the pack ice (Aarset 1991, Werner 1997.…”

Section: Introductionmentioning

confidence: 99%

Seasonal variability in abundance, respiration and lipid composition of Arctic under-ice amphipods

Werner¹,

Auel²

2005

Mar. Ecol. Prog. Ser.

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The Arctic under-ice amphipods Apherusa glacialis, Onisimus glacialis, O. nanseni andGammarus wilkitzkii are autochthonous below the pack ice, i.e. they occur in this habitat during all seasons. In this study, seasonal dynamics in abundance were only evident in A. glacialis. Respiration rates did not differ significantly between summer and winter in any species, indicating that the under-ice habitat is a comparatively stable environment in terms of seasonal variations. The assessment of total lipids and fatty acid biomarkers revealed differences in feeding behaviour and overwintering strategy among the amphipod species. A. glacialis is strictly herbivorous, feeding on ice-algae at the underside of the ice during the productive season. The species overwinters in an active state, fuelled at least partly by internal lipid reserves stored during summer. O. glacialis switches from a predominantly herbivorous diet in summer to metazoan prey, including planktonic copepods, in winter, so that lipid catabolism is less important to winter survival. The congener O. nanseni relies on an opportunistic omnivorous diet throughout the year, with a higher proportion of metazoan prey during summer compared to O. glacialis. G. wilkitzkii is able to exploit a wide spectrum of food sources, from predominantly ice algae in summer to more ice fauna and planktonic copepods in winter. This species partly meets its energy requirements by using internal lipid reserves during winter.

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The ecophysiology of under-ice fauna

Cited by 23 publications

References 71 publications

The adaptive significance of chromatophores in the Arctic under-ice amphipod Apherusa glacialis

The adaptive significance of chromatophores in the Arctic under-ice amphipod Apherusa glacialis

Characteristics of meiofauna in extreme marine ecosystems: a review

Seasonal variability in abundance, respiration and lipid composition of Arctic under-ice amphipods

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