Surface exchange between the Weddell and Scotia Seas

Thompson, Andrew F.; Youngs, Madeleine K.

doi:10.1002/2013gl058114

Cited by 22 publications

(22 citation statements)

References 29 publications

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“…The relative isolation of South Orkney Islands is corroborated by drifter data, which reveal a northward flow of Weddell Sea water across the South Scotia Ridge between Elephant Island and the South Orkney Islands, acting as a dynamic barrier to exchange between populations at the Antarctic Peninsula and South Orkney Islands (Thompson et al. ; Thompson and Youngs ).…”

Section: Discussionmentioning

confidence: 79%

Oceanography and life history predict contrasting genetic population structure in two Antarctic fish species

Young

Belchier

Hauser

et al. 2015

Evolutionary Applications

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Understanding the key drivers of population connectivity in the marine environment is essential for the effective management of natural resources. Although several different approaches to evaluating connectivity have been used, they are rarely integrated quantitatively. Here, we use a ‘seascape genetics’ approach, by combining oceanographic modelling and microsatellite analyses, to understand the dominant influences on the population genetic structure of two Antarctic fishes with contrasting life histories, Champsocephalus gunnari and Notothenia rossii. The close accord between the model projections and empirical genetic structure demonstrated that passive dispersal during the planktonic early life stages is the dominant influence on patterns and extent of genetic structuring in both species. The shorter planktonic phase of C. gunnari restricts direct transport of larvae between distant populations, leading to stronger regional differentiation. By contrast, geographic distance did not affect differentiation in N. rossii, whose longer larval period promotes long-distance dispersal. Interannual variability in oceanographic flows strongly influenced the projected genetic structure, suggesting that shifts in circulation patterns due to climate change are likely to impact future genetic connectivity and opportunities for local adaptation, resilience and recovery from perturbations. Further development of realistic climate models is required to fully assess such potential impacts.

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Section: Discussionmentioning

confidence: 79%

Oceanography and life history predict contrasting genetic population structure in two Antarctic fish species

Young

Belchier

Hauser

et al. 2015

Evolutionary Applications

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show abstract

“…As atmospheric deposition is limited in the HTV region [ Cassar et al ., ], the main iron sources are likely from ice melt and obduction of subsurface iron‐rich waters. In the Weddell Sea, studies have found that weakening winds can shift the boundary current toward shore, increasing the interaction between offshore waters and the shelf [ Thompson and Youngs , ; Youngs et al ., ]. In the WAP region, IAV in northerly wind strength could influence the extent of interactions of the boundary current with iron‐rich shelf waters.…”

Section: Discussionmentioning

confidence: 99%

Interannual variability in net community production at the Western Antarctic Peninsula region (1997–2014)

Cassar

Huang

et al. 2016

JGR Oceans

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In this study, we examined the interannual variability of net community production (NCP) in the Western Antarctic Peninsula (WAP) using in situ O2/Ar‐NCP estimates (2008–2014) and satellite data (SeaWiFS and MODIS‐Aqua) from 1997 to 2014. We found that NCP generally first peaks offshore and follows sea‐ice retreat from offshore to inshore. Annually integrated NCP (ANCP) displays an onshore‐to‐offshore gradient, with coastal and shelf regions up to 8 times more productive than offshore regions. We examined potential drivers of interannual variability in the ANCP using an Empirical Orthogonal Function (EOF) analysis. The EOF's first mode explains ∼50% of the variance, with high interannual variability observed seaward of the shelf break. The first principal component is significantly correlated with the day of sea‐ice retreat (R = −0.58, p < 0.05), as well as the Southern Annular Mode (SAM) and El Niño Southern Oscillation (ENSO) climate indices in austral spring. Although the most obvious pathway by which the day of sea‐ice retreat influences NCP is by controlling light availability early in the growing season, we found that the effect of day of sea‐ice retreat on NCP persists throughout the growing season, suggesting that additional controls, such as iron availability, are preconditioned or correlated to the day of sea‐ice retreat.

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“…1; Jiang et al 2013). In the BS, cold salty Weddell-shelf water enters near JI and flows south along the northern coast of the Antarctic Peninsula (von Gyldenfeldt et al 2002, Thompson et al 2009, Thompson & Youngs 2013. Water from the Antarctic Circumpolar Current (ACC; Bellings hausen surface water, and Upper Circumpolar Deep Water) enters the BS from the southwest at the surface and at mid-depths, and flows northeast along the southern coast of the South Shetland Islands (Gordon & Nowlin 1978, Gordon et al 2000.…”

Section: Study Areamentioning

confidence: 99%

Overwinter habitat selection by Antarctic krill under varying sea-ice conditions: implications for top predators and fishery management

Reiss¹,

Cossio²,

Santora³

et al. 2017

Mar. Ecol. Prog. Ser.

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Climate change will affect Antarctic krill Euphausia superba, krill-dependent predators, and fisheries in the Southern Ocean as areas typically covered by sea ice become ice-free in some winters. Research cruises conducted around the South Shetland Islands of the Antarctic Peninsula during winters with contrasting ice conditions provide the first acoustic estimates of krill biomass, habitat use, and association with top predators to examine potential interactions with the krill fishery. Krill abundance was very low in offshore waters during all winters. In Bransfield Strait, median krill abundance was an order of magnitude higher (8 krill m ), and this pattern was observed in all winters regardless of ice cover. Acoustic estimates of krill biomass were also an order of magnitude higher (~5 500 000 metric tons [t] in 2014) than a 15 yr summer average (520 000 t). Looking at krilldependent predators, during winter, crabeater seals Lobodon carcinophagus were concentrated in Bransfield Strait where ice provided habitat, while Antarctic fur seals Arctocephalus gazella were more broadly distributed. Krill overwinter in coastal basin environments independent of ice and primary production and in an area that is becoming more frequently icefree. While long-term projections of climate change have focused on changing krill habitat and productivity declines, more immediate impacts of ongoing climate change include increased risks of negative fishery−krill−predator interactions, alteration of upper trophic level community structure, and changes in the pelagic ecology of this system. Development of management strategies to mitigate the increased risk to krill populations and their dependent predators over management timescales will be necessary to minimize the impacts of long-term climate change.

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Surface exchange between the Weddell and Scotia Seas

Cited by 22 publications

References 29 publications

Oceanography and life history predict contrasting genetic population structure in two Antarctic fish species

Oceanography and life history predict contrasting genetic population structure in two Antarctic fish species

Interannual variability in net community production at the Western Antarctic Peninsula region (1997–2014)

Overwinter habitat selection by Antarctic krill under varying sea-ice conditions: implications for top predators and fishery management

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