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Benthic-pelagic coupling in the Barents Sea: an integrated data-model framework.

https://arctichealth.org/en/permalink/ahliterature304883
Source
Philos Trans A Math Phys Eng Sci. 2020 Oct 02; 378(2181):20190359
Publication Type
Journal Article
Date
Oct-02-2020
Author
Felipe S Freitas
Katharine R Hendry
Sian F Henley
Johan C Faust
Allyson C Tessin
Mark A Stevenson
Geoffrey D Abbott
Christian März
Sandra Arndt
Author Affiliation
School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen's Road, Bristol BS8 1RJ, UK.
Source
Philos Trans A Math Phys Eng Sci. 2020 Oct 02; 378(2181):20190359
Date
Oct-02-2020
Language
English
Publication Type
Journal Article
Abstract
The Barents Sea is experiencing long-term climate-driven changes, e.g. modification in oceanographic conditions and extensive sea ice loss, which can lead to large, yet unquantified disruptions to ecosystem functioning. This key region hosts a large fraction of Arctic primary productivity. However, processes governing benthic and pelagic coupling are not mechanistically understood, limiting our ability to predict the impacts of future perturbations. We combine field observations with a reaction-transport model approach to quantify organic matter (OM) processing and disentangle its drivers. Sedimentary OM reactivity patterns show no gradients relative to sea ice extent, being mostly driven by seafloor spatial heterogeneity. Burial of high reactivity, marine-derived OM is evident at sites influenced by Atlantic Water (AW), whereas low reactivity material is linked to terrestrial inputs on the central shelf. Degradation rates are mainly driven by aerobic respiration (40-75%), being greater at sites where highly reactive material is buried. Similarly, ammonium and phosphate fluxes are greater at those sites. The present-day AW-dominated shelf might represent the future scenario for the entire Barents Sea. Our results represent a baseline systematic understanding of seafloor geochemistry, allowing us to anticipate changes that could be imposed on the pan-Arctic in the future if climate-driven perturbations persist. This article is part of the theme issue 'The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning'.
PubMed ID
32862804 View in PubMed
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Benthic phosphorus cycling within the Eurasian marginal sea ice zone.

https://arctichealth.org/en/permalink/ahliterature304881
Source
Philos Trans A Math Phys Eng Sci. 2020 Oct 02; 378(2181):20190358
Publication Type
Journal Article
Date
Oct-02-2020
Author
Allyson Tessin
Christian März
Monika Kedra
Jens Matthiessen
Nathalie Morata
Michael Nairn
Matt O'Regan
Ilka Peeken
Author Affiliation
Department of Geology, Kent State University, Kent, OH, USA.
Source
Philos Trans A Math Phys Eng Sci. 2020 Oct 02; 378(2181):20190358
Date
Oct-02-2020
Language
English
Publication Type
Journal Article
Abstract
The Arctic Ocean region is currently undergoing dramatic changes, which will likely alter the nutrient cycles that underpin Arctic marine ecosystems. Phosphate is a key limiting nutrient for marine life but gaps in our understanding of the Arctic phosphorus (P) cycle persist. In this study, we investigate the benthic burial and recycling of phosphorus using sediments and pore waters from the Eurasian Arctic margin, including the Barents Sea slope and the Yermak Plateau. Our results highlight that P is generally lost from sediments with depth during organic matter respiration. On the Yermak Plateau, remobilization of P results in a diffusive flux of P to the seafloor of between 96 and 261?µmol?m-2?yr-1. On the Barents Sea slope, diffusive fluxes of P are much larger (1736-2449?µmol?m-2?yr-1), but these fluxes are into near-surface sediments rather than to the bottom waters. The difference in cycling on the Barents Sea slope is controlled by higher fluxes of fresh organic matter and active iron cycling. As changes in primary productivity, ocean circulation and glacial melt continue, benthic P cycling is likely to be altered with implications for P imported into the Arctic Ocean Basin. This article is part of the theme issue 'The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning'.
PubMed ID
32862806 View in PubMed
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The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning.

https://arctichealth.org/en/permalink/ahliterature304872
Source
Philos Trans A Math Phys Eng Sci. 2020 Oct 02; 378(2181):20200266
Publication Type
Journal Article
Date
Oct-02-2020
Author
Martin Solan
Philippe Archambault
Paul E Renaud
Christian März
Author Affiliation
School of Ocean and Earth Science, National Oceanography Centre Southampton, University of Southampton, Waterfront Campus, European Way, Southampton SO14 3ZH, UK.
Source
Philos Trans A Math Phys Eng Sci. 2020 Oct 02; 378(2181):20200266
Date
Oct-02-2020
Language
English
Publication Type
Journal Article
PubMed ID
32862816 View in PubMed
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Does Arctic warming reduce preservation of organic matter in Barents Sea sediments?

https://arctichealth.org/en/permalink/ahliterature304877
Source
Philos Trans A Math Phys Eng Sci. 2020 Oct 02; 378(2181):20190364
Publication Type
Journal Article
Date
Oct-02-2020
Author
Johan C Faust
Mark A Stevenson
Geoffrey D Abbott
Jochen Knies
Allyson Tessin
Isobel Mannion
Ailbe Ford
Robert Hilton
Jeffrey Peakall
Christian März
Author Affiliation
School of Earth and Environment, The University of Leeds, Leeds, UK.
Source
Philos Trans A Math Phys Eng Sci. 2020 Oct 02; 378(2181):20190364
Date
Oct-02-2020
Language
English
Publication Type
Journal Article
Abstract
Over the last few decades, the Barents Sea experienced substantial warming, an expansion of relatively warm Atlantic water and a reduction in sea ice cover. This environmental change forces the entire Barents Sea ecosystem to adapt and restructure and therefore changes in pelagic-benthic coupling, organic matter sedimentation and long-term carbon sequestration are expected. Here we combine new and existing organic and inorganic geochemical surface sediment data from the western Barents Sea and show a clear link between the modern ecosystem structure, sea ice cover and the organic carbon and CaCO3 contents in Barents Sea surface sediments. Furthermore, we discuss the sources of total and reactive iron phases and evaluate the spatial distribution of organic carbon bound to reactive iron. Consistent with a recent global estimate we find that on average 21.0?±?8.3 per cent of the total organic carbon is associated to reactive iron (fOC-FeR) in Barents Sea surface sediments. The spatial distribution of fOC-FeR, however, seems to be unrelated to sea ice cover, Atlantic water inflow or proximity to land. Future Arctic warming might, therefore, neither increase nor decrease the burial rates of iron-associated organic carbon. However, our results also imply that ongoing sea ice reduction and the associated alteration of vertical carbon fluxes might cause accompanied shifts in the Barents Sea surface sedimentary organic carbon content, which might result in overall reduced carbon sequestration in the future. This article is part of the theme issue 'The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning'.
PubMed ID
32862811 View in PubMed
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Millennial scale persistence of organic carbon bound to iron in Arctic marine sediments.

https://arctichealth.org/en/permalink/ahliterature303745
Source
Nat Commun. 2021 01 12; 12(1):275
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Date
01-12-2021
Author
Johan C Faust
Allyson Tessin
Ben J Fisher
Mark Zindorf
Sonia Papadaki
Katharine R Hendry
Katherine A Doyle
Christian März
Author Affiliation
School of Earth and Environment, The University of Leeds, Leeds, UK. J.Faust@leeds.ac.uk.
Source
Nat Commun. 2021 01 12; 12(1):275
Date
01-12-2021
Language
English
Publication Type
Journal Article
Research Support, Non-U.S. Gov't
Abstract
Burial of organic material in marine sediments represents a dominant natural mechanism of long-term carbon sequestration globally, but critical aspects of this carbon sink remain unresolved. Investigation of surface sediments led to the proposition that on average 10-20% of sedimentary organic carbon is stabilised and physically protected against microbial degradation through binding to reactive metal (e.g. iron and manganese) oxides. Here we examine the long-term efficiency of this rusty carbon sink by analysing the chemical composition of sediments and pore waters from four locations in the Barents Sea. Our findings show that the carbon-iron coupling persists below the uppermost, oxygenated sediment layer over thousands of years. We further propose that authigenic coprecipitation is not the dominant factor of the carbon-iron bounding in these Arctic shelf sediments and that a substantial fraction of the organic carbon is already bound to reactive iron prior deposition on the seafloor.
PubMed ID
33436568 View in PubMed
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Transformation of organic matter in a Barents Sea sediment profile: coupled geochemical and microbiological processes.

https://arctichealth.org/en/permalink/ahliterature304875
Source
Philos Trans A Math Phys Eng Sci. 2020 Oct 02; 378(2181):20200223
Publication Type
Journal Article
Date
Oct-02-2020
Author
Mark A Stevenson
Johan C Faust
Luiza L Andrade
Felipe S Freitas
Neil D Gray
Karen Tait
Katharine R Hendry
Robert G Hilton
Sian F Henley
Allyson Tessin
Peter Leary
Sonia Papadaki
Ailbe Ford
Christian März
Geoffrey D Abbott
Author Affiliation
School of Natural and Environmental Sciences, Newcastle University, Newcastle upon Tyne, NE1 7RU, UK.
Source
Philos Trans A Math Phys Eng Sci. 2020 Oct 02; 378(2181):20200223
Date
Oct-02-2020
Language
English
Publication Type
Journal Article
Abstract
Process-based, mechanistic investigations of organic matter transformation and diagenesis directly beneath the sediment-water interface (SWI) in Arctic continental shelves are vital as these regions are at greatest risk of future change. This is in part due to disruptions in benthic-pelagic coupling associated with ocean current change and sea ice retreat. Here, we focus on a high-resolution, multi-disciplinary set of measurements that illustrate how microbial processes involved in the degradation of organic matter are directly coupled with inorganic and organic geochemical sediment properties (measured and modelled) as well as the extent/depth of bioturbation. We find direct links between aerobic processes, reactive organic carbon and highest abundances of bacteria and archaea in the uppermost layer (0-4.5?cm depth) followed by dominance of microbes involved in nitrate/nitrite and iron/manganese reduction across the oxic-anoxic redox boundary (approx. 4.5-10.5?cm depth). Sulfate reducers dominate in the deeper (approx. 10.5-33?cm) anoxic sediments which is consistent with the modelled reactive transport framework. Importantly, organic matter reactivity as tracked by organic geochemical parameters (n-alkanes, n-alkanoic acids, n-alkanols and sterols) changes most dramatically at and directly below the SWI together with sedimentology and biological activity but remained relatively unchanged across deeper changes in sedimentology. This article is part of the theme issue 'The changing Arctic Ocean: consequences for biological communities, biogeochemical processes and ecosystem functioning'.
PubMed ID
32862813 View in PubMed
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6 records – page 1 of 1.