Antarctic Futures: An Assessment of Climate-Driven Changes in Ecosystem Structure, Function, and Service Provisioning in the Southern Ocean

Abstract

In this article, we analyze the impacts of climate change on Antarctic marine ecosystems. Observations demonstrate large-scale changes in the physical variables and circulation of the Southern Ocean driven by warming, stratospheric ozone depletion, and a positive Southern Annular Mode. Alterations in the physical environment are driving change through all levels of Antarctic marine food webs, which differ regionally. The distributions of key species, such as Antarctic krill, are also changing. Differential responses among predators reflect differences in species ecology. The impacts of climate change on Antarctic biodiversity will likely vary for different communities and depend on species range. Coastal communities and those of sub-Antarctic islands, especially range-restricted endemic communities, will likely suffer the greatest negative consequences of climate change. Simultaneously, ecosystem services in the Southern Ocean will likely increase. Such decoupling of ecosystem services and endemic species will require consideration in the management of human activities such as fishing in Antarctic marine ecosystems.

Benthic ecoregionalization based on echinoid fauna of the Southern Ocean supports current proposals of Antarctic Marine Protected Areas under IPCC scenarios of climate change

“…Marine life of the SO displays unique physiological characteristics and life-history traits including high levels of endemism (Griffiths, Barnes, & Linse, 2009;Kaiser et al, 2013;Saucède, Pierrat, & David, 2014), adaptations to seasonally subzero water temperatures with high sensitivity to increase in temperature due to their narrow thermal niche (Cheng & William, 2007;Peck, 2016Peck, , 2018Portner, Peck, & Somero, 2007), and brooding (David & Mooi, 1990;Hunter & Halanych, 2008;Sewell & Hofmann, 2011), which make it particularly vulnerable to environmental changes (Guillaumot et al, 2018;Ingels et al, 2012;Lohrer, Cummings, & Thrush, 2013;Peck, 2005;Peck, Morley, & Clark, 2010;Peck, Webb, & Bailey, 2004). Multiple impacts of climate change have been documented on SO benthic marine ecosystems that are particularly endangered (Bonsell & Dunton, 2018;Constable et al, 2014;Le Guen et al, 2018;Reygondeau & Huettmann, 2014;Rogers et al, 2020;Sen Gupta et al, 2009). As highlighted previously, changes are not equivalent across the whole SO and can reach various degrees of importance depending on the region.…”

Successful ecosystem-based management of Antarctic krill should address uncertainties in krill recruitment, behaviour and ecological adaptation

“…The Southwest (SW) Atlantic sector of the Southern Ocean (SO), where 70% of the krill population resides 2 , is the main focus of the modern krill fishery 8,9 , which is managed by the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR). The SW Atlantic sector is also amongst the global regions most affected by climate change 10,11 . The krill fishery has existed for 50 years, and over this time has seen changes in geographic focus, fleet nationality composition, and the technologies used to locate and catch krill.…”

Long-term changes in habitat and trophic level of Southern Ocean squid in relation to environmental conditions

“…Accordingly, our biological sampler, the wandering albatross, has presumably also maintained broadly similar foraging range and habitat preferences over the decades; this is supported by the weaker effect of year than breeding stage or sex on latitude and longitude reached at the furthest point from the colony reached by tracked birds 46 . In most of the literature, the extent of habitat available for native species (including many endemics) in Antarctic waters was predicted to decline, constraining distributions, whereas lower-latitude species were considered likely to extend their range 34,47,48 . Although most squid in our study appear to have a preference for subantarctic waters 32,43 , given that some individuals had isotopic signatures typical of adjacent water masses, neither the Antarctic Polar Front nor the Subtropical Front (STF) appear to represent major ecological barriers, even though the temperature differential between subtropical and subantarctic waters is substantial (~ 5 °C) 49,50 .…”