Climate change impacts on Antarctic krill behaviour and population dynamics

Kawaguchi, So; Atkinson, Angus; Bahlburg, Dominik; Bernard, Kim S.; Cavan, Emma L.; Cox, Martin J.; Hill, Simeon L.; Meyer, Bettina; Veytia, Devi

doi:10.1038/s43017-023-00504-y

Cited by 4 publications

(3 citation statements)

References 194 publications

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“…While it is clear that some of the links in the food web are changing over time, the reasons are not yet always clear. Rogers et al, 2020;Johnston et al, 2022;Kawaguchi et al, 2024), and we do not repeat these here.…”

Section: Introductionmentioning

confidence: 75%

Observing change in pelagic animals as sampling methods shift: the case of Antarctic krill

Hill,

Atkinson,

Arata

et al. 2024

Front. Mar. Sci.

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Understanding and managing the response of marine ecosystems to human pressures including climate change requires reliable large-scale and multi-decadal information on the state of key populations. These populations include the pelagic animals that support ecosystem services including carbon export and fisheries. The use of research vessels to collect information using scientific nets and acoustics is being replaced with technologies such as autonomous moorings, gliders, and meta-genetics. Paradoxically, these newer methods sample pelagic populations at ever-smaller spatial scales, and ecological change might go undetected in the time needed to build up large-scale, long time series. These global-scale issues are epitomised by Antarctic krill (Euphausia superba), which is concentrated in rapidly warming areas, exports substantial quantities of carbon and supports an expanding fishery, but opinion is divided on how resilient their stocks are to climatic change. Based on a workshop of 137 krill experts we identify the challenges of observing climate change impacts with shifting sampling methods and suggest three tractable solutions. These are to: improve overlap and calibration of new with traditional methods; improve communication to harmonise, link and scale up the capacity of new but localised sampling programs; and expand opportunities from other research platforms and data sources, including the fishing industry. Contrasting evidence for both change and stability in krill stocks illustrates how the risks of false negative and false positive diagnoses of change are related to the temporal and spatial scale of sampling. Given the uncertainty about how krill are responding to rapid warming we recommend a shift towards a fishery management approach that prioritises monitoring of stock status and can adapt to variability and change.

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Section: Introductionmentioning

confidence: 75%

Observing change in pelagic animals as sampling methods shift: the case of Antarctic krill

Hill,

Atkinson,

Arata

et al. 2024

Front. Mar. Sci.

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“…Lack of sea ice has profound impacts on Southern Ocean biota with many marine organisms, from krill to whales, feeding or being dependent on productivity in the sea ice zone (Bengtson Nash et al, 2023;Kawaguchi et al, 2024;Pallin et al, 2023). Sea ice also controls the amount of visible radiation reaching the water; a shorter duration of sea ice can cause ecosystem shifts in polar benthic communities from invertebrate to algal dominated (Clark et al, 2013;Gómez et al, 2019).…”

Section: The E X Tended Ozone Hole and Loss Of S E A Ice: Impac Ts Fo...mentioning

confidence: 99%

“…, lower panel). Krill populations are contracting southwards along with sea ice loss and warming oceans, and this has consequences for the animals that feed on them, including whales(Bengtson Nash et al, 2023;Kawaguchi et al, 2024;Pallin et al, 2023).Many animals breed on sea ice and on Antarctic beaches and coastal areas throughout the spring and summer. We know that increased UV-B radiation increases risk for skin cancer and cataracts F I G U R E 2 Changes in potential for exposure of Antarctic organisms to UV radiation during spring and summer.…”

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confidence: 99%

Extended ozone depletion and reduced snow and ice cover—Consequences for Antarctic biota

Robinson,

Revell,

Mackenzie

et al. 2024

Global Change Biology

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Stratospheric ozone, which has been depleted in recent decades by the release of anthropogenic gases, is critical for shielding the biosphere against ultraviolet‐B (UV‐B) radiation. Although the ozone layer is expected to recover before the end of the 21st century, a hole over Antarctica continues to appear each year. Ozone depletion usually peaks between September and October, when fortunately, most Antarctic terrestrial vegetation and soil biota is frozen, dormant and protected under snow cover. Similarly, much marine life is protected by sea ice cover. The ozone hole used to close before the onset of Antarctic summer, meaning that most biota were not exposed to severe springtime UV‐B fluxes. However, in recent years, ozone depletion has persisted into December, which marks the beginning of austral summer. Early summertime ozone depletion is concerning: high incident UV‐B radiation coincident with snowmelt and emergence of vegetation will mean biota is more exposed. The start of summer is also peak breeding season for many animals, thus extreme UV‐B exposure (UV index up to 14) may come at a vulnerable time in their life cycle. Climate change, including changing wind patterns and strength, and particularly declining sea ice, are likely to compound UV‐B exposure of Antarctic organisms, through earlier ice and snowmelt, heatwaves and droughts. Antarctic field research conducted decades ago tended to study UV impacts in isolation and more research that considers multiple climate impacts, and the true magnitude and timing of current UV increases is needed.

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A new Activity Monitor for Aquatic Zooplankter (AMAZE) allows the recording of swimming activity in wild-caught Antarctic krill (Euphausia superba)

Hüppe,

Bahlburg,

Busack

et al. 2024

Sci Rep

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Antarctic krill (Euphausia superba, hereafter krill) is a pelagic living crustacean and a key species in the Southern Ocean ecosystem. Krill builds up a huge biomass and its synchronized behavioral patterns, such as diel vertical migration (DVM), substantially impact ecosystem structure and carbon sequestration. However, the mechanistic basis of krill DVM is unknown and previous studies of krill behavior in the laboratory were challenged by complex behavior and large variability. Using a new experimental set-up, we recorded the swimming activity of individual wild-caught krill under light–dark cycles. Krill individuals exhibited differential phototactic responses to the light regime provided. However, using a new activity metric, we showed for the first time a consistent nocturnal increase in krill swimming activity in a controlled environment. Krill swimming activity in the new set-up was strongly synchronized with the light–dark cycle, similar to the diel vertical migration pattern of krill in the field when the krill were sampled for the experiment, demonstrated by hydroacoustic recordings. The new set-up presents a promising tool for investigating the mechanisms underlying krill behavioral patterns, which will increase our understanding of ecological interactions, the spatial distribution of populations, and their effects on biogeochemical cycles in the future.

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Climate change impacts on Antarctic krill behaviour and population dynamics

Cited by 4 publications

References 194 publications

Observing change in pelagic animals as sampling methods shift: the case of Antarctic krill

Observing change in pelagic animals as sampling methods shift: the case of Antarctic krill

Extended ozone depletion and reduced snow and ice cover—Consequences for Antarctic biota

A new Activity Monitor for Aquatic Zooplankter (AMAZE) allows the recording of swimming activity in wild-caught Antarctic krill (Euphausia superba)

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