Biodiversity signature of the Last Glacial Maximum at South Georgia, Southern Ocean

Barnes, David K. A.; Sands, Chester J.; Hogg, Oliver T.; Robinson, Ben J.O.; Downey, Rachel; Smith, James A

doi:10.1111/jbi.12855

Cited by 20 publications

(32 citation statements)

References 24 publications

(49 reference statements)

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“…These two schemes differ in complexity, data sources and emphasis; [2] scheme divides the shelf into essential four categories (old sediments, young sediments, fjords and rocky moraines), uses data from two Darwin Initiative supported research cruises and is based on substrata, benthic species composition, and by proxy geological age. In contrast the [16] scheme involves more (varied) categories, using available data-based information which are physical (e.g.…”

Section: Introductionmentioning

confidence: 99%

Functional group diversity is key to Southern Ocean benthic carbon pathways

Barnes

Sands

2017

PLoS ONE

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High latitude benthos are globally important in terms of accumulation and storage of ocean carbon, and the feedback this is likely to have on regional warming. Understanding this ecosystem service is important but difficult because of complex taxonomic diversity, history and geography of benthic biomass. Using South Georgia as a model location (where the history and geography of benthic biology is relatively well studied) we investigated whether the composition of functional groups were critical to benthic accumulation, immobilization and burial pathway to sequestration–and also aid their study through simplification of identification. We reclassified [1], [2]) morphotype and carbon mass data to 13 functional groups, for each sample of 32 sites around the South Georgia continental shelf. We investigated the influence on carbon accumulation, immobilization and sequestration estimate by multiple factors including the compositions of functional groups. Functional groups showed high diversity within and between sites, and within and between habitat types. Carbon storage was not linked to a functional group in particular but accumulation and immobilization increased with the number of functional groups present and the presence of hard substrata. Functional groups were also important to carbon burial rate, which increased with the presence of mixed (hard and soft substrata). Functional groups showed high surrogacy for taxonomic composition and were useful for examining contrasting habitat categorization. Functional groups not only aid marine carbon storage investigation by reducing time and the need for team size and speciality, but also important to benthic carbon pathways per se. There is a distinct geography to seabed carbon storage; seabed boulder-fields are hotspots of carbon accumulation and immobilization, whilst the interface between such boulder-fields and sediments are key places for burial and sequestration.

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Section: Introductionmentioning

confidence: 99%

Functional group diversity is key to Southern Ocean benthic carbon pathways

Barnes

Sands

2017

PLoS ONE

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“…Habitats that have been subject to fundamental environmental change often show corresponding patterns of decreasing species diversity, because recovery and colonisation processes are happening at finite speeds and require time to reach a new equilibrium [ 68 , 69 ]. This observation is true across many temporal and spatial scales.…”

Section: Discussionmentioning

confidence: 99%

Different feeding strategies in Antarctic scavenging amphipods and their implications for colonisation success in times of retreating glaciers

Seefeldt¹,

Campana²,

Deregibus³

et al. 2017

Front Zool

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BackgroundScavenger guilds are composed of a variety of species, co-existing in the same habitat and sharing the same niche in the food web. Niche partitioning among them can manifest in different feeding strategies, e.g. during carcass feeding. In the bentho-pelagic realm of the Southern Ocean, scavenging amphipods (Lysianassoidea) are ubiquitous and occupy a central role in decomposition processes. Here we address the question whether scavenging lysianassoid amphipods employ different feeding strategies during carcass feeding, and whether synergistic feeding activities may influence carcass decomposition. To this end, we compared the relatively large species Waldeckia obesa with the small species Cheirimedon femoratus, Hippomedon kergueleni, and Orchomenella rotundifrons during fish carcass feeding (Notothenia spp.). The experimental approach combined ex situ feeding experiments, behavioural observations, and scanning electron microscopic analyses of mandibles. Furthermore, we aimed to detect ecological drivers for distribution patterns of scavenging amphipods in the Antarctic coastal ecosystems of Potter Cove. In Potter Cove, the climate-driven rapid retreat of the Fourcade Glacier is causing various environmental changes including the provision of new marine habitats to colonise. While in the newly ice-free areas fish are rare, macroalgae have already colonised hard substrates. Assuming that a temporal dietary switch may increase the colonisation success of the most abundant lysianassoids C. femoratus and H. kergueleni, we aimed to determine their consumption rates (g food x g amphipods−1 x day−1) and preferences of macroalgae and fish.ResultsWe detected two functional groups with different feeding strategies among scavenging amphipods during carcass feeding: carcass ‘opener’ and ‘squeezer’. Synergistic effects between these groups were not statistically verified under the conditions tested. C. femoratus switched its diet when fish was not available by consuming macroalgae (about 0.2 day−1) but preferred fish by feeding up to 80% of its own mass daily. Contrary, H. kergueleni rejected macroalgae entirely and consumed fish with a maximal rate of 0.8 day−1.ConclusionThis study reveals functional groups in scavenging shallow-water amphipods and provides new information on coastal intraguild niche partitioning. We conclude that the dietary flexibility of C. femoratus is a potential ecological driver and central to its success in the colonisation of newly available ice-free Antarctic coastal habitats.Electronic supplementary materialThe online version of this article (10.1186/s12983-017-0248-3) contains supplementary material, which is available to authorized users.

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“…Studies of Antarctic shelf bryozoans and sea spiders support the refugia hypothesis (Barnes and Kuklinski, 2010;Leese et al, 2015;Barnes et al, 2016). Based on older and current patterns of ecological disturbance and subsequent recolonization, invertebrate communities inhabiting the shallower and deeper regions of the Antarctic shelf may be comprised of significantly different species assemblages (Jones et al, 2007;Boger, 2011;Barnes et al, 2016).…”

Section: Introductionmentioning

confidence: 88%

“…Since many benthic invertebrates inhabiting the shelf exhibit eurybathic distributions (Brey et al, 1996), the post-glacial recolonization process may have been sourced by populations from the continental slope and abyssal regions, surrounding continents and islands, or other surviving refuge habitats (Barnes and Kuklinski, 2010). Studies of Antarctic shelf bryozoans and sea spiders support the refugia hypothesis (Barnes and Kuklinski, 2010;Leese et al, 2015;Barnes et al, 2016). Based on older and current patterns of ecological disturbance and subsequent recolonization, invertebrate communities inhabiting the shallower and deeper regions of the Antarctic shelf may be comprised of significantly different species assemblages (Jones et al, 2007;Boger, 2011;Barnes et al, 2016).…”

Section: Introductionmentioning

confidence: 93%

“…Although several studies include bryozoans as being one of the more common and diverse members of the shelf fauna (e.g., Barnes and Kuklinski, 2010;Barnes et al, 2016;Figuerola et al, 2018), the impact of expansive bryozoan secondary structures on the surrounding community has not been evaluated on a wide geographic scale (Wood et al, 2013). Evaluating the geographic distribution of habitat-forming bryozoan communities in other Antarctic regions based on published studies using direct sampling or remote-imaging techniques (or both) can be difficult due to interpretational differences in categorizing bryozoan-rich habitats.…”

Section: Biogeography and Composition Of Antarctic Habitat-forming Bmentioning

confidence: 99%

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Compositional Differences in the Habitat-Forming Bryozoan Communities of the Antarctic Shelf

et al. 2018

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In some areas of the Antarctic shelf, bryozoans are abundant, acting as ecosystem engineers creating secondary structures with wide benthic coverage and harboring numerous other species. As the combined forces of global warming and ocean acidification threaten these habitats, we measured the composition of habitat-forming bryozoan communities using two techniques for imaging the sea floor, a YoYo-camera system and the AWI Ocean Floor Observation System (OFOS). YoYo-camera transects of the Bellingshausen, Amundsen, and Ross Seas were conducted during a research cruise on the R/V Nathaniel B. Palmer in 2013. OFOS transects included sites in the northern Palmer Archipelago where it borders the Scotia Sea and the Weddell Sea as part of the DynAMO project during the PS81 and PS96 cruises of R/V Polarstern in 2013 and 2015-16, respectively. Areas of bryozoan colonies were measured from the sea floor images using machine-learning algorithms available through the Trainable Weka Segmentation plugin developed for FIJI software. Habitat-forming bryozoan communities in the Palmer Archipelago and Ross Sea were largely composed of anascan flustrid species with finely mineralized skeletons, and to a lesser extent by other ascophoran lepraliomorph and umbonulomorph species having more robustly mineralized skeletons. Although habitat-forming bryozoan communities in the shallower (200 m) sites of the Weddell Sea also contained flustrid species, percent area and composition of flustrid bryozoans declined with increasing depth. Lepraliomorph and umbonulomorph bryozoan morphotypes were more abundant in the Weddell Sea, maintaining their relative percent area and increasing their percent composition between 200 − 400 m. Moreover, our analyses of species composition based on externally gathered datasets show similar trends among sites, depths, and degrees of colony mineralization to our seabed imaging study. Variation present in the bryozoan species compositions of the Amundsen and Bellingshausen Seas suggest that these areas potentially represent divergent bryozoan communities requiring further validation via remote imaging surveys. Overall, compositional differences among Antarctic habitat-forming bryozoan communities are likely influenced by the combined effects of seasonal ice scour and carbonate chemistry, which in an increasingly acidified and warming ocean may put the communities of the eastern Weddell Sea at greater risk.

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Biodiversity signature of the Last Glacial Maximum at South Georgia, Southern Ocean

Cited by 20 publications

References 24 publications

Functional group diversity is key to Southern Ocean benthic carbon pathways

Functional group diversity is key to Southern Ocean benthic carbon pathways

Different feeding strategies in Antarctic scavenging amphipods and their implications for colonisation success in times of retreating glaciers

Compositional Differences in the Habitat-Forming Bryozoan Communities of the Antarctic Shelf

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