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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of comparative physiology 154 (1984), S. 593-599 
    ISSN: 1432-136X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Performance by perfused isolated hearts of sea raven (Hemitripterus americanus) and skate (Raja erinecea), representatives of teleost and elasmobranch fishes, respectively, was monitored over a 30 min period under conditions of variable metabolic fuel availability. In both preparations initial cardiac output and hence fuel delivery to the myocardia were comparable to in vivo levels. Pressure development and hence overall work rate of the sea raven heart was also similar to in vivo levels. Fuel deprived sea raven hearts entered into a modest but significant contractile failure which could be prevented by the inclusion of 10 mM glucose or 1.0 mM palmitate in the perfusion medium. Addition of the glycolytic inhibitor iodoacetate to the medium resulted in rapid heart failure. Performance in the presence of iodoacetate could be improved by the inclusion of palmitate, lactate, or acetoacetate in the perfusion media but only high physiological levels of palmitate could completely alleviate the effect of iodoacetate. The inclusion of 1.0 mM palmitate in the perfusion medium of skate hearts resulted in a significant decrease in performance relative to fuel deprived hearts. Addition of iodoacetate to the medium resulted in rapid contractile failure. Hearts perfused with medium containing both iodoacetate and acetoacetate performed as well as fuel deprived hearts, indicating that this ketone body is an effective metabolic fuel. The performance data reported here are consistent with a previously established biochemical framework. The teleost heart has the capability of utilizing exogenous fatty acid as a metabolic fuel and this substrate may be able to support the contractile process independently. In contrast, fatty acid metabolism in the elasmobranch heart is poorly developed and appears to be more dependent upon the catabolism of blood borne ketone bodies.
    Type of Medium: Electronic Resource
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  • 2
    Publication Date: 2021-01-12
    Description: The South Sandwich Volcanic Arc is one of the most remote and enigmatic arcs on Earth. Sporadic observations from rare cloudfree satellite images—and even rarer in situ reports—provide glimpses into a dynamic arc system characterised by persistent gas emissions and frequent eruptive activity. Our understanding of the state of volcanic activity along this arc is incomplete compared to arcs globally. To fill this gap, we present here detailed geological and volcanological observations made during an expedition to the South Sandwich Islands in January 2020.We report the first in situ measurements of gas chemistry, emission rate and carbon isotope composition from along the arc. We show that Mt. Michael on Saunders Island is a persistent source of gas emissions, releasing 145±59 t day−1 SO2 in a plume characterised by a CO2/SO2 molar ratio of 1.8 ± 0.2. Combining this CO2/SO2 ratio with our independent SO2 emission rate measured near simultaneously, we derive a CO2 flux of 179 ± 76 t day−1. Outgassing from low temperature (90–100 °C) fumaroles is pervasive at the active centres of Candlemas and Bellingshausen, with measured gas compositions indicative of interaction between magmatic fluids and hydrothermal systems. Carbon isotope measurements of dilute plume and fumarole gases from along the arc indicate a magmatic δ13C of − 4.5 ± 2.0‰. Interpreted most simply, this result suggests a carbon source dominated by mantle-derived carbon. However, based on a carbon mass balance from sediment core ODP 701, we show that mixing between depleted upper mantle and a subduction component composed of sediment and altered crust is also permissible.We conclude that, although remote, the South Sandwich Volcanic Arc is an ideal tectonic setting in which to explore geochemical processes in a young, developing arc.
    Description: This expedition was funded by public donations raised by Quark Expeditions Ltd., by the Government of South Georgia and the South Sandwich Islands (GSGSSI) and by individual contributions. This work was carried out under RAP 2019/025 issued by GSGSSI. EJL was supported by a Leverhulme Early Career Fellowship. A.A. and M.B. acknowledge funding from Miur (Grant N. 2017LMNLAW). K.W. acknowledges support from the Mount Everest Foundation (20-06)
    Description: Published
    Description: id 3
    Description: 4V. Processi pre-eruttivi
    Description: 6V. Pericolosità vulcanica e contributi alla stima del rischio
    Description: 1IT. Reti di monitoraggio e sorveglianza
    Description: JCR Journal
    Keywords: South Sandwich Volcanic Arc ; Volcanic gas emissions ; Volcanic activity ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 3
    Publication Date: 2022-05-25
    Description: Author Posting. © The Author(s), 2017. This is the author's version of the work. It is posted here under a nonexclusive, irrevocable, paid-up, worldwide license granted to WHOI. It is made available for personal use, not for redistribution. The definitive version was published in Biology Letters 13 (2017): 20170241, doi:10.1098/rsbl.2017.0241.
    Description: Identifying the at-sea distribution of wide ranging 20 marine predators is critical to understanding their ecology. Advances in electronic tracking devices and intrinsic biogeochemical markers have greatly improved our ability to track animal movements on ocean-wide scales. Here we show that, in combination with direct tracking, stable carbon isotope analysis of essential amino acids in tail feathers provides the ability to track the movement patterns of two, wide-ranging penguin species over ocean basin scales. In addition, we use this isotopic approach across multiple breeding colonies in the Scotia Arc to evaluate migration trends at a regional scale that would be logistically challenging using direct tracking alone.
    Description: Funded by the National Marine Sanctuary Foundation (GLS tags), Ocean Life Institute (M.J.P, L.H., S.R.T), Darwin Initiative (T.H.), and SeaWorld Bush Gardens Conservation Fund (M.J.P, S.R.T).
    Keywords: Migration ; Geolocation (GLS) ; Seabird ; Stable isotopes
    Repository Name: Woods Hole Open Access Server
    Type: Preprint
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  • 4
    Publication Date: 2022-05-26
    Description: © The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 4 (2014): 5024, doi:10.1038/srep05024.
    Description: Climate change is a major threat to global biodiversity. Antarctic ecosystems are no exception. Investigating past species responses to climatic events can distinguish natural from anthropogenic impacts. Climate change produces ‘winners’, species that benefit from these events and ‘losers’, species that decline or become extinct. Using molecular techniques, we assess the demographic history and population structure of Pygoscelis penguins in the Scotia Arc related to climate warming after the Last Glacial Maximum (LGM). All three pygoscelid penguins responded positively to post-LGM warming by expanding from glacial refugia, with those breeding at higher latitudes expanding most. Northern (Pygoscelis papua papua) and Southern (Pygoscelis papua ellsworthii) gentoo sub-species likely diverged during the LGM. Comparing historical responses with the literature on current trends, we see Southern gentoo penguins are responding to current warming as they did during post-LGM warming, expanding their range southwards. Conversely, Adélie and chinstrap penguins are experiencing a ‘reversal of fortunes’ as they are now declining in the Antarctic Peninsula, the opposite of their response to post-LGM warming. This suggests current climate warming has decoupled historic population responses in the Antarctic Peninsula, favoring generalist gentoo penguins as climate change ‘winners’, while Adélie and chinstrap penguins have become climate change ‘losers’.
    Description: We thank the Zoological Society of London, Quark Expeditions, Exodus Travels ltd., Oceanites, the Holly Hill Charitable Trust, the Charities Advisory Trust and an U.S. National Science Foundation (NSF) Office of Polar Programs grant (ANT-0739575) for funding.
    Keywords: Climate-change ecology ; Molecular ecology ; Molecular evolution ; Population genetics
    Repository Name: Woods Hole Open Access Server
    Type: Article
    Format: application/pdf
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  • 5
    Publication Date: 2022-05-26
    Description: © The Author(s), 2018. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Scientific Reports 8 (2018): 3926, doi:10.1038/s41598-018-22313-w.
    Description: Despite concerted international effort to track and interpret shifts in the abundance and distribution of Adélie penguins, large populations continue to be identified. Here we report on a major hotspot of Adélie penguin abundance identified in the Danger Islands off the northern tip of the Antarctic Peninsula (AP). We present the first complete census of Pygoscelis spp. penguins in the Danger Islands, estimated from a multi-modal survey consisting of direct ground counts and computer-automated counts of unmanned aerial vehicle (UAV) imagery. Our survey reveals that the Danger Islands host 751,527 pairs of Adélie penguins, more than the rest of AP region combined, and include the third and fourth largest Adélie penguin colonies in the world. Our results validate the use of Landsat medium-resolution satellite imagery for the detection of new or unknown penguin colonies and highlight the utility of combining satellite imagery with ground and UAV surveys. The Danger Islands appear to have avoided recent declines documented on the Western AP and, because they are large and likely to remain an important hotspot for avian abundance under projected climate change, deserve special consideration in the negotiation and design of Marine Protected Areas in the region.
    Description: We gratefully acknowledge the financial support of the Dalio Foundation, Inc. through the Dalio Explore Fund, which provided all the financing for the Danger Island Expedition. We would like to thank additional support for analysis from the National Science Foundation (NSF PLR&GSS 1255058 - H.J.L. and P.M.; NSF PLR 1443585 – M.J.P.) and the National Aeronautical and Space Administration (NNX14AC32G; H.J.L. and M.S.). Geospatial support for the analysis of high resolution satellite imagery provided by the Polar Geospatial Center under NSF PLR awards 1043681 & 1559691.
    Repository Name: Woods Hole Open Access Server
    Type: Article
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  • 6
    Publication Date: 2019-12-02
    Description: The Southern Ocean is in an era of significant change. Historic overharvesting of marine mammals and recent climatic warming have cascading impacts on resource availability and, in turn, ecosystem structure and function. We examined trophic responses of sympatric chinstrap (Pygoscelis antarctica) and gentoo (Pygoscelis papua) penguins to nearly 100 y of shared environmental change in the Antarctic Peninsula region using compound-specific stable isotope analyses of museum specimens. A century ago, gentoo penguins fed almost exclusively on low-trophic level prey, such as krill, during the peak of historic overexploitation of marine mammals, which was hypothesized to have resulted in a krill surplus. In the last 40 y, gentoo penguin trophic position has increased a full level as krill declined in response to recent climate change, increased competition from recovering marine mammal populations, and the development of a commercial krill fishery. A shifting isotopic baseline supporting gentoo penguins suggests a concurrent increase in coastal productivity over this time. In contrast, chinstrap penguins exhibited no change in trophic position, despite variation in krill availability over the past century. The specialized foraging niche of chinstrap penguins likely renders them more sensitive to changes in krill availability, relative to gentoo penguins, as evinced by their declining population trends in the Antarctic Peninsula over the past 40 y. Over the next century, similarly divergent trophic and population responses are likely to occur among Antarctic krill predators if climate change and other anthropogenic impacts continue to favor generalist over specialist species.
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
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  • 7
    Publication Date: 2019-12-16
    Description: Climate shifts are key drivers of ecosystem change. Despite the critical importance of Antarctica and the Southern Ocean for global climate, the extent of climate-driven ecological change in this region remains controversial. In particular, the biological effects of changing sea ice conditions are poorly understood. We hypothesize that rapid postglacial reductions in sea ice drove biological shifts across multiple widespread Southern Ocean species. We test for demographic shifts driven by climate events over recent millennia by analyzing population genomic datasets spanning 3 penguin genera (Eudyptes,Pygoscelis, andAptenodytes). Demographic analyses for multiple species (macaroni/royal, eastern rockhopper, Adélie, gentoo, king, and emperor) currently inhabiting southern coastlines affected by heavy sea ice conditions during the Last Glacial Maximum (LGM) yielded genetic signatures of near-simultaneous population expansions associated with postglacial warming. Populations of the ice-adapted emperor penguin are inferred to have expanded slightly earlier than those of species requiring ice-free terrain. These concerted high-latitude expansion events contrast with relatively stable or declining demographic histories inferred for 4 penguin species (northern rockhopper, western rockhopper, Fiordland crested, and Snares crested) that apparently persisted throughout the LGM in ice-free habitats. Limited genetic structure detected in all ice-affected species across the vast Southern Ocean may reflect both rapid postglacial colonization of subantarctic and Antarctic shores, in addition to recent genetic exchange among populations. Together, these analyses highlight dramatic, ecosystem-wide responses to past Southern Ocean climate change and suggest potential for further shifts as warming continues.
    Print ISSN: 0027-8424
    Electronic ISSN: 1091-6490
    Topics: Biology , Medicine , Natural Sciences in General
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  • 8
    Publication Date: 2016-06-16
    Print ISSN: 1754-2189
    Electronic ISSN: 1750-2799
    Topics: Natural Sciences in General
    Published by Springer Nature
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