1
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Andresen CS, Karlsson NB, Straneo F, Schmidt S, Andersen TJ, Eidam EF, Bjørk AA, Dartiguemalle N, Dyke LM, Vermassen F, Gundel IE. Sediment discharge from Greenland's marine-terminating glaciers is linked with surface melt. Nat Commun 2024; 15:1332. [PMID: 38351087 PMCID: PMC10864362 DOI: 10.1038/s41467-024-45694-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 01/30/2024] [Indexed: 02/16/2024] Open
Abstract
Sediment discharged from the Greenland Ice Sheet delivers nutrients to marine ecosystems around Greenland and shapes seafloor habitats. Current estimates of the total sediment flux are constrained by observations from land-terminating glaciers only. Addressing this gap, our study presents a budget derived from observations at 30 marine-margin locations. Analyzing sediment cores from nine glaciated fjords, we assess spatial deposition since 1950. A significant correlation is established between mass accumulation rates, normalized by surface runoff, and distance down-fjord. This enables calculating annual sediment flux at any fjord point based on nearby marine-terminating outlet glacier melt data. Findings reveal a total annual sediment flux of 1.324 + /- 0.79 Gt yr-1 over the period 2010-2020 from all marine-terminating glaciers to the fjords. These estimates are valuable for studies aiming to understand the basal ice sheet conditions and for studies predicting ecosystem changes in Greenland's fjords and offshore areas as the ice sheet melts and sediment discharge increase.
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Affiliation(s)
- Camilla S Andresen
- Geological Survey of Denmark and Greenland, Department of Glaciology and Climate, Øster Voldgade 10, 1350, Copenhagen K, Denmark.
| | - Nanna B Karlsson
- Geological Survey of Denmark and Greenland, Department of Glaciology and Climate, Øster Voldgade 10, 1350, Copenhagen K, Denmark
| | | | - Sabine Schmidt
- CNRS, Univ. Bordeaux, Bordeaux INP, UMR 5805, F-33600, Pessac, France
| | - Thorbjørn J Andersen
- Department of Geosciences and Natural Resource Management, Univ. of Copenhagen, 1350, Copenhagen K, Denmark
| | - Emily F Eidam
- Oregon State University, Burt Hall 218, 2651 SW Orchard Avenue, Corvallis, OR, 97331, USA
| | - Anders A Bjørk
- Department of Geological Sciences, Stockholm University, 106 91, Stockholm, Sweden
| | - Nicolas Dartiguemalle
- Geological Survey of Denmark and Greenland, Department of Glaciology and Climate, Øster Voldgade 10, 1350, Copenhagen K, Denmark
| | - Laurence M Dyke
- Geological Survey of Denmark and Greenland, Department of Glaciology and Climate, Øster Voldgade 10, 1350, Copenhagen K, Denmark
| | - Flor Vermassen
- Department of Geological Sciences, Stockholm University, 106 91, Stockholm, Sweden
| | - Ida E Gundel
- Geological Survey of Denmark and Greenland, Department of Glaciology and Climate, Øster Voldgade 10, 1350, Copenhagen K, Denmark
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2
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Holland MM, Louchart A, Artigas LF, Ostle C, Atkinson A, Rombouts I, Graves CA, Devlin M, Heyden B, Machairopoulou M, Bresnan E, Schilder J, Jakobsen HH, Lloyd-Hartley H, Tett P, Best M, Goberville E, McQuatters-Gollop A. Major declines in NE Atlantic plankton contrast with more stable populations in the rapidly warming North Sea. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 898:165505. [PMID: 37451457 DOI: 10.1016/j.scitotenv.2023.165505] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2023] [Revised: 06/16/2023] [Accepted: 07/11/2023] [Indexed: 07/18/2023]
Abstract
Plankton form the base of marine food webs, making them important indicators of ecosystem status. Changes in the abundance of plankton functional groups, or lifeforms, can affect higher trophic levels and can indicate important shifts in ecosystem functioning. Here, we extend this knowledge by combining data from Continuous Plankton Recorder and fixed-point stations to provide the most comprehensive analysis of plankton time-series for the North-East Atlantic and North-West European shelf to date. We analysed 24 phytoplankton and zooplankton datasets from 15 research institutions to map 60-year abundance trends for 8 planktonic lifeforms. Most lifeforms decreased in abundance (e.g. dinoflagellates: -5 %, holoplankton: -7 % decade-1), except for meroplankton, which increased 12 % decade-1, reflecting widespread changes in large-scale and localised processes. K-means clustering of assessment units according to abundance trends revealed largely opposing trend direction between shelf and oceanic regions for most lifeforms, with North Sea areas characterised by increasing coastal abundance, while abundance decreased in North-East Atlantic areas. Individual taxa comprising each phytoplankton lifeform exhibited similar abundance trends, whereas taxa grouped within zooplankton lifeforms were more variable. These regional contrasts are counterintuitive, since the North Sea which has undergone major warming, changes in nutrients, and past fisheries perturbation has changed far less, from phytoplankton to fish larvae, as compared to the more slowly warming North-East Atlantic with lower nutrient supply and fishing pressure. This more remote oceanic region has shown a major and worrying decline in the traditional food web. Although the causal mechanisms remain unclear, declining abundance of key planktonic lifeforms in the North-East Atlantic, including diatoms and copepods, are a cause of major concern for the future of food webs and should provide a red flag to politicians and policymakers about the prioritisation of future management and adaptation measures required to ensure future sustainable use of the marine ecosystem.
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Affiliation(s)
- Matthew M Holland
- Marine Conservation Research Group, University of Plymouth, Drake Circus, Plymouth PL4 8AA, United Kingdom.
| | - Arnaud Louchart
- Laboratoire d'Océanologie et Geosciences, UMR 8187 LOG, Centre National de la Recherche Scientifique, Université du Littoral Côte d'Opale, Université de Lille, IRD, Wimereux, France
| | - Luis Felipe Artigas
- Laboratoire d'Océanologie et Geosciences, UMR 8187 LOG, Centre National de la Recherche Scientifique, Université du Littoral Côte d'Opale, Université de Lille, IRD, Wimereux, France
| | - Clare Ostle
- The Marine Biological Association (MBA), The Laboratory, Citadel Hill, Plymouth PL1 2PB, United Kingdom
| | - Angus Atkinson
- Plymouth Marine Laboratory (PML), Prospect Place, The Hoe, PL1 3DH, Plymouth, United Kingdom
| | - Isabelle Rombouts
- Flanders Marine Institute (VLIZ), Marine Observation Centre (MOC), InnovOcean Campus, Jacobsenstraat 1, 8400 Oostende, Belgium
| | - Carolyn A Graves
- Centre for Environment, Fisheries and Aquaculture Science (Cefas), Barrack Rd, Weymouth DT4 8UB, United Kingdom
| | - Michelle Devlin
- Centre for Environment, Fisheries and Aquaculture Science (Cefas), Barrack Rd, Weymouth DT4 8UB, United Kingdom
| | - Birgit Heyden
- AquaEcology GmbH & Co. KG, Steinkamp 19, 26125 Oldenburg, Germany
| | | | - Eileen Bresnan
- Marine Scotland Science, 375 Victoria Road, AB11 9DB Aberdeen, Scotland, United Kingdom
| | - Jos Schilder
- Waterkwaliteit en Natuurbeheer, Rijkswaterstaat, Postbus 2232, 3500 GE Utrecht, Netherlands
| | - Hans H Jakobsen
- Department of Ecoscience, Aarhus University, Frederiksborgvej 399, 4000 Roskilde, Denmark
| | - Hannah Lloyd-Hartley
- Dove Marine Laboratory, Newcastle University, Front Street, Cullercoats, North Shields NE30 4PZ, United Kingdom
| | - Paul Tett
- Scottish Association for Marine Science, Oban, PA37 1QA, Scotland, United Kingdom
| | - Mike Best
- Environment Agency, Kingfisher House, Goldhay Way, Peterborough PE2 5ZR, United Kingdom
| | - Eric Goberville
- Unité Biologie des Organismes et Ecosystèmes Aquatiques (BOREA), Muséum National d'Histoire Naturelle, CNRS, IRD, Sorbonne Université, Université de Caen Normandie, Université des Antilles, Paris, France
| | - Abigail McQuatters-Gollop
- Marine Conservation Research Group, University of Plymouth, Drake Circus, Plymouth PL4 8AA, United Kingdom
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3
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Shetye S, Pratihary A, Shenoy D, Kurian S, Gauns M, Uskaikar H, Naik B, Nandakumar K, Borker S. Rice husk as a potential source of silicate to oceanic phytoplankton. THE SCIENCE OF THE TOTAL ENVIRONMENT 2023; 879:162941. [PMID: 36934917 DOI: 10.1016/j.scitotenv.2023.162941] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 03/10/2023] [Accepted: 03/14/2023] [Indexed: 05/17/2023]
Abstract
Global oceans are witnessing changes in the phytoplankton community composition due to various environmental stressors such as rising temperature, stratification, nutrient limitation, and ocean acidification. The Arabian Sea is undergoing changes in its phytoplankton community composition, especially during winter, with the diatoms being replaced by harmful algal blooms (HABs) of dinoflagellates. Recent studies have already highlighted dissolved silicate (DSi) limitation and change in Silicon (Si)/Nitrogen (N) ratios as the factors responsible for the observed changes in the phytoplankton community in the Arabian Sea. Our investigation also revealed Si/N < 1 in the northern Arabian Sea, indicating DSi limitation, especially during winter. Here, we demonstrate that rice husk with its phytoliths is an important source of bioavailable DSi for oceanic phytoplankton. Our experiment showed that a rice husk can release ∼12 μM of DSi in 15 days and can release DSi for ∼20 days. The DSi availability increased diatom abundance up to ∼9 times. The major benefitted diatom species from DSi enrichment were Nitzshia spp., Striatella spp., Navicula spp., Dactiliosolen spp., and Leptocylindrus spp. The increase in diatom abundance was accompanied by an increase in fucoxanthin and dimethyl sulphide (DMS), an anti-greenhouse gas. Thus, the rice husk with its buoyancy and slow DSi release has the potential to reduce HABs, and increase diatoms and fishery resources in addition to carbon dioxide (CO2) sequestration in DSi-limited oceanic regions such as the Arabian Sea. Rice husk if released at the formation site of the Subantarctic mode water in the Southern Ocean could supply DSi to the thermocline in the global oceans thereby increasing diatom blooms and consequently the biotic carbon sequestration potential of the entire ocean.
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Affiliation(s)
- Suhas Shetye
- CSIR-National Institute of Oceanography, Dona Paula 403 004, Goa, India.
| | - Anil Pratihary
- CSIR-National Institute of Oceanography, Dona Paula 403 004, Goa, India
| | - Damodar Shenoy
- CSIR-National Institute of Oceanography, Dona Paula 403 004, Goa, India
| | - Siby Kurian
- CSIR-National Institute of Oceanography, Dona Paula 403 004, Goa, India
| | - Mangesh Gauns
- CSIR-National Institute of Oceanography, Dona Paula 403 004, Goa, India
| | - Hema Uskaikar
- CSIR-National Institute of Oceanography, Dona Paula 403 004, Goa, India
| | - Bhagyashri Naik
- CSIR-National Institute of Oceanography, Dona Paula 403 004, Goa, India
| | - K Nandakumar
- CSIR-National Institute of Oceanography, Dona Paula 403 004, Goa, India
| | - Sidhesh Borker
- CSIR-National Institute of Oceanography, Dona Paula 403 004, Goa, India
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4
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Lin G, Qiao J, Steier P, Danielsen M, Guðnason K, Joensen HP, Stedmon CA. Tracing Atlantic water transit time in the subarctic and Arctic Atlantic using 99Tc- 233U- 236U. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 851:158276. [PMID: 36029821 DOI: 10.1016/j.scitotenv.2022.158276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 08/18/2022] [Accepted: 08/21/2022] [Indexed: 06/15/2023]
Abstract
The pathway and transport time of Atlantic water passing northern Europe can be traced via anthropogenic radioisotopes released from reprocessing of spent nuclear fuels at Sellafield (SF) and La Hague (LH). These reprocessing derived radioisotopes, with extremely low natural background, are source specific and unique fingerprints for Atlantic water. This study explores a new approach using 99Tc-233U-236U tracer to estimate the transit time of Atlantic water in the coast of Greenland. We isolate the reprocessing plants (RP) signal of 236U (236URP) by incorporating 233U measurements and combine this with 99Tc which solely originates from RP, to estimate the transit time of Atlantic water circulating from Sellafield to the coast of Greenland-Iceland-Faroe Islands. Both being conservative radioisotopes, the temporal variation of 99Tc/236URP ratio in Atlantic water is only influenced by their historic discharges from RP, thus 99Tc/236URP can potentially be a robust tracer to track the transport of Atlantic water in the North Atlantic-Arctic region. Based on our observation data of 99Tc-233U-236U in seawater and the proposed 99Tc/236URP tracer approach, Atlantic water transit times were estimated to be 16-22, 25 and 25 years in the coast of Greenland, Iceland and Faroe Island, respectively. Our estimates from northeast Greenland coastal waters agree with earlier results (17-22 years). Therefore, this work provides an independent approach to estimate Atlantic water transit time with which to compare estimates from ocean modelling and other radiotracer approaches.
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Affiliation(s)
- Gang Lin
- Department of Environmental and Resource Engineering, Technical University of Denmark, DK-4000 Roskilde, Denmark
| | - Jixin Qiao
- Department of Environmental and Resource Engineering, Technical University of Denmark, DK-4000 Roskilde, Denmark.
| | - Peter Steier
- VERA Laboratory, Faculty of Physics, Isotope Physics, University of Vienna, Währinger Straße 17, A-1090 Vienna, Austria
| | | | | | | | - Colin A Stedmon
- National Institute of Aquatic Resources, Technical University of Denmark, Kemitorvet, 2800 Kgs. Lyngby, Denmark
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5
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de la Vega C, Buchanan PJ, Tagliabue A, Hopkins JE, Jeffreys RM, Frie AK, Biuw M, Kershaw J, Grecian J, Norman L, Smout S, Haug T, Mahaffey C. Multi-decadal environmental change in the Barents Sea recorded by seal teeth. GLOBAL CHANGE BIOLOGY 2022; 28:3054-3065. [PMID: 35202506 PMCID: PMC9314922 DOI: 10.1111/gcb.16138] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2021] [Revised: 02/09/2022] [Accepted: 02/13/2022] [Indexed: 06/14/2023]
Abstract
Multiple environmental forcings, such as warming and changes in ocean circulation and nutrient supply, are affecting the base of Arctic marine ecosystems, with cascading effects on the entire food web through bottom-up control. Stable nitrogen isotopes (δ15 N) can be used to detect and unravel the impact of these forcings on this unique ecosystem, if the many processes that affect the δ15 N values are constrained. Combining unique 60-year records from compound specific δ15 N biomarkers on harp seal teeth alongside state-of-the-art ocean modelling, we observed a significant decline in the δ15 N values at the base of the Barents Sea food web from 1951 to 2012. This strong and persistent decadal trend emerges due to the combination of anthropogenic atmospheric nitrogen deposition in the Atlantic, increased northward transport of Atlantic water through Arctic gateways and local feedbacks from increasing Arctic primary production. Our results suggest that the Arctic ecosystem has been responding to anthropogenically induced local and remote drivers, linked to changing ocean biology, chemistry and physics, for at least 60 years. Accounting for these trends in δ15 N values at the base of the food web is essential to accurately detect ecosystem restructuring in this rapidly changing environment.
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Affiliation(s)
- Camille de la Vega
- School of Environmental SciencesUniversity of LiverpoolLiverpoolUK
- Present address:
Leibniz Institute for Baltic Sea Research, WarnemündeRostock18119Germany
| | | | | | | | | | | | - Martin Biuw
- Institute of Marine ResearchFram CentreTromsøNorway
| | - Joanna Kershaw
- Sea Mammal Research UnitScottish Oceans InstituteUniversity of St AndrewsSt AndrewsUK
| | - James Grecian
- Sea Mammal Research UnitScottish Oceans InstituteUniversity of St AndrewsSt AndrewsUK
| | - Louisa Norman
- School of Environmental SciencesUniversity of LiverpoolLiverpoolUK
| | - Sophie Smout
- Sea Mammal Research UnitScottish Oceans InstituteUniversity of St AndrewsSt AndrewsUK
| | - Tore Haug
- Institute of Marine ResearchFram CentreTromsøNorway
| | - Claire Mahaffey
- School of Environmental SciencesUniversity of LiverpoolLiverpoolUK
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6
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Tuerena RE, Mahaffey C, Henley SF, de la Vega C, Norman L, Brand T, Sanders T, Debyser M, Dähnke K, Braun J, März C. Nutrient pathways and their susceptibility to past and future change in the Eurasian Arctic Ocean. AMBIO 2022; 51:355-369. [PMID: 34914030 PMCID: PMC8692559 DOI: 10.1007/s13280-021-01673-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 09/20/2021] [Accepted: 11/12/2021] [Indexed: 05/25/2023]
Abstract
Climate change is altering nutrient cycling within the Arctic Ocean, having knock-on effects to Arctic ecosystems. Primary production in the Arctic is principally nitrogen-limited, particularly in the western Pacific-dominated regions where denitrification exacerbates nitrogen loss. The nutrient status of the eastern Eurasian Arctic remains under debate. In the Barents Sea, primary production has increased by 88% since 1998. To support this rapid increase in productivity, either the standing stock of nutrients has been depleted, or the external nutrient supply has increased. Atlantic water inflow, enhanced mixing, benthic nitrogen cycling, and land-ocean interaction have the potential to alter the nutrient supply through addition, dilution or removal. Here we use new datasets from the Changing Arctic Ocean program alongside historical datasets to assess how nitrate and phosphate concentrations may be changing in response to these processes. We highlight how nutrient dynamics may continue to change, why this is important for regional and international policy-making and suggest relevant research priorities for the future.
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Affiliation(s)
| | - Claire Mahaffey
- Department of Earth, Ocean and Ecological Sciences, School of Environmental Sciences, University of Liverpool, 4 Brownlow Street, Liverpool, L69 3GP Merseyside UK
| | - Sian F. Henley
- School of GeoSciences, University of Edinburgh, James Hutton Road, Edinburgh, EH9 3FE UK
| | - Camille de la Vega
- Department of Earth, Ocean and Ecological Sciences, School of Environmental Sciences, University of Liverpool, 4 Brownlow Street, Liverpool, L69 3GP Merseyside UK
| | - Louisa Norman
- Department of Earth, Ocean and Ecological Sciences, School of Environmental Sciences, University of Liverpool, 4 Brownlow Street, Liverpool, L69 3GP Merseyside UK
| | - Tim Brand
- Scottish Association for Marine Science, Oban, PA37 1QA UK
| | - Tina Sanders
- Institute for Carbon Cycles, Helmholtz-Zentrum Hereon, Max-Planck-Str. 1, 21502 Geesthacht, Germany
| | - Margot Debyser
- School of GeoSciences, University of Edinburgh, James Hutton Road, Edinburgh, EH9 3FE UK
| | - Kirstin Dähnke
- Institute for Carbon Cycles, Helmholtz-Zentrum Hereon, Max-Planck-Str. 1, 21502 Geesthacht, Germany
| | - Judith Braun
- Scottish Association for Marine Science, Oban, PA37 1QA UK
| | - Christian März
- School of Earth & Environment, University of Leeds, Leeds, LS2 9JT UK
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7
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Lotze HK, Mellon S, Coyne J, Betts M, Burchell M, Fennel K, Dusseault MA, Fuller SD, Galbraith E, Garcia Suarez L, de Gelleke L, Golombek N, Kelly B, Kuehn SD, Oliver E, MacKinnon M, Muraoka W, Predham IT, Rutherford K, Shackell N, Sherwood O, Sibert EC, Kienast M. Long-term ocean and resource dynamics in a hotspot of climate change. Facets (Ott) 2022. [DOI: 10.1139/facets-2021-0197] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The abundance, distribution, and size of marine species are linked to temperature and nutrient regimes and are profoundly affected by humans through exploitation and climate change. Yet little is known about long-term historical links between ocean environmental changes and resource abundance to provide context for current and potential future trends and inform conservation and management. We synthesize >4000 years of climate and marine ecosystem dynamics in a Northwest Atlantic region currently undergoing rapid changes, the Gulf of Maine and Scotian Shelf. This period spans the late Holocene cooling and recent warming and includes both Indigenous and European influence. We compare environmental records from instrumental, sedimentary, coral, and mollusk archives with ecological records from fossils, archaeological, historical, and modern data, and integrate future model projections of environmental and ecosystem changes. This multidisciplinary synthesis provides insight into multiple reference points and shifting baselines of environmental and ecosystem conditions, and projects a near-future departure from natural climate variability in 2028 for the Scotian Shelf and 2034 for the Gulf of Maine. Our work helps advancing integrative end-to-end modeling to improve the predictive capacity of ecosystem forecasts with climate change. Our results can be used to adjust marine conservation strategies and network planning and adapt ecosystem-based management with climate change.
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Affiliation(s)
- Heike K. Lotze
- Department of Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Stefanie Mellon
- Department of Oceanography, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Jonathan Coyne
- Department of Oceanography, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Matthew Betts
- Canadian Museum of History, Gatineau, QC K1A 0M8, Canada
| | - Meghan Burchell
- Department of Archaeology, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
| | - Katja Fennel
- Department of Oceanography, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Marisa A. Dusseault
- Department of Archaeology, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
| | | | - Eric Galbraith
- Department of Earth and Planetary Sciences, McGill University, Montreal, QC H3A 0E8, Canada
- Institut de Ciència i Tecnologia Ambientals (ICTA-UAB), Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain
| | - Lina Garcia Suarez
- Department of Oceanography, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Laura de Gelleke
- Department of Oceanography, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Nina Golombek
- Department of Earth and Environmental Sciences, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | | | - Sarah D. Kuehn
- Department of Archaeology, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
| | - Eric Oliver
- Department of Oceanography, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Megan MacKinnon
- Department of Archaeology, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
| | - Wendy Muraoka
- Department of Oceanography, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Ian T.G. Predham
- Department of Archaeology, Memorial University of Newfoundland, St. John’s, NL A1C 5S7, Canada
| | - Krysten Rutherford
- Department of Oceanography, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Nancy Shackell
- Ocean and Ecosystem Sciences Division, Fisheries and Oceans Canada, Dartmouth, NS B3B 1J6, Canada
| | - Owen Sherwood
- Department of Earth and Environmental Sciences, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Elizabeth C. Sibert
- Department of Earth and Planetary Sciences, Yale University, PO Box 208109, New Haven, CT 06520, USA
- Yale Institute for Biospheric Studies, Yale University, 170 Whitney Avenue, New Haven, CT 06511, USA
| | - Markus Kienast
- Department of Oceanography, Dalhousie University, Halifax, NS B3H 4R2, Canada
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8
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Tesi T, Muschitiello F, Mollenhauer G, Miserocchi S, Langone L, Ceccarelli C, Panieri G, Chiggiato J, Nogarotto A, Hefter J, Ingrosso G, Giglio F, Giordano P, Capotondi L. Rapid Atlantification along the Fram Strait at the beginning of the 20th century. SCIENCE ADVANCES 2021; 7:eabj2946. [PMID: 34818051 PMCID: PMC8612687 DOI: 10.1126/sciadv.abj2946] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
The recent expansion of Atlantic waters into the Arctic Ocean represents undisputable evidence of the rapid changes occurring in this region. Understanding the past variability of this “Atlantification” is thus crucial in providing a longer perspective on the modern Arctic changes. Here, we reconstruct the history of Atlantification along the eastern Fram Strait during the past 800 years using precisely dated paleoceanographic records based on organic biomarkers and benthic foraminiferal data. Our results show rapid changes in water mass properties that commenced in the early 20th century—several decades before the documented Atlantification by instrumental records. Comparison with regional records suggests a poleward expansion of subtropical waters since the end of the Little Ice Age in response to a rapid hydrographic reorganization in the North Atlantic. Understanding of this mechanism will require further investigations using climate model simulations.
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Affiliation(s)
- Tommaso Tesi
- Istituto di Scienze Polari, Consiglio Nazionale delle Ricerche ISP-CNR, 40129 Bologna, Italy
- Corresponding author.
| | - Francesco Muschitiello
- Department of Geography, University of Cambridge, Cambridge CB2 3EN, UK
- NORCE Norwegian Research Centre, 5007 Bergen, Norway
| | - Gesine Mollenhauer
- Alfred Wegener Institute, Helmholtz Center for Polar and Marine Sciences, 27570 Bremerhaven, Germany
- MARUM Center for Marine Environmental Research, Department of Geosciences, University of Bremen, Bremen, Germany
| | - Stefano Miserocchi
- Istituto di Scienze Polari, Consiglio Nazionale delle Ricerche ISP-CNR, 40129 Bologna, Italy
| | - Leonardo Langone
- Istituto di Scienze Polari, Consiglio Nazionale delle Ricerche ISP-CNR, 40129 Bologna, Italy
| | - Chiara Ceccarelli
- Dipartimento di Scienze Biologiche, Geologiche ed Ambientali—BiGeA, 40126 Bologna, Italy
| | - Giuliana Panieri
- CAGE—Center of Arctic Gas Hydrate, Environment and Climate, Department of Geolosciences, UiT The Arctic University of Norway, Tromsø, Norway
| | - Jacopo Chiggiato
- Istituto di Scienze Marine–Consiglio Nazionale delle Ricerche ISMAR-CNR, 40129 Bologna, Italy
| | - Alessio Nogarotto
- Istituto di Scienze Polari, Consiglio Nazionale delle Ricerche ISP-CNR, 40129 Bologna, Italy
- Campus Scientifico, Università Ca’ Foscari Venezia, 30172 Venezia Mestre, Italy
| | - Jens Hefter
- Alfred Wegener Institute, Helmholtz Center for Polar and Marine Sciences, 27570 Bremerhaven, Germany
| | - Gianmarco Ingrosso
- Istituto di Scienze Polari, Consiglio Nazionale delle Ricerche ISP-CNR, 40129 Bologna, Italy
| | - Federico Giglio
- Istituto di Scienze Polari, Consiglio Nazionale delle Ricerche ISP-CNR, 40129 Bologna, Italy
| | - Patrizia Giordano
- Istituto di Scienze Polari, Consiglio Nazionale delle Ricerche ISP-CNR, 40129 Bologna, Italy
| | - Lucilla Capotondi
- Istituto di Scienze Marine–Consiglio Nazionale delle Ricerche ISMAR-CNR, 40129 Bologna, Italy
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9
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Kazanidis G, Henry L, Vad J, Johnson C, De Clippele LH, Roberts JM. Sensitivity of a cold‐water coral reef to interannual variability in regional oceanography. DIVERS DISTRIB 2021. [DOI: 10.1111/ddi.13363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Affiliation(s)
- Georgios Kazanidis
- Changing Oceans Research Group School of GeoSciences University of Edinburgh Edinburgh UK
| | - Lea‐Anne Henry
- Changing Oceans Research Group School of GeoSciences University of Edinburgh Edinburgh UK
| | - Johanne Vad
- Changing Oceans Research Group School of GeoSciences University of Edinburgh Edinburgh UK
| | | | | | - J. Murray Roberts
- Changing Oceans Research Group School of GeoSciences University of Edinburgh Edinburgh UK
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Faster Atlantic currents drive poleward expansion of temperate phytoplankton in the Arctic Ocean. Nat Commun 2020; 11:1705. [PMID: 32249780 PMCID: PMC7136244 DOI: 10.1038/s41467-020-15485-5] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Accepted: 03/03/2020] [Indexed: 12/03/2022] Open
Abstract
The Arctic marine biome, shrinking with increasing temperature and receding sea-ice cover, is tightly connected to lower latitudes through the North Atlantic. By flowing northward through the European Arctic Corridor (the main Arctic gateway where 80% of in- and outflow takes place), the North Atlantic Waters transport most of the ocean heat, but also nutrients and planktonic organisms toward the Arctic Ocean. Using satellite-derived altimetry observations, we reveal an increase, up to two-fold, in North Atlantic current surface velocities over the last 24 years. More importantly, we show evidence that the North Atlantic current and its variability shape the spatial distribution of the coccolithophore Emiliania huxleyi (Ehux), a tracer for temperate ecosystems. We further demonstrate that bio-advection, rather than water temperature as previously assumed, is a major mechanism responsible for the recent poleward intrusions of southern species like Ehux. Our findings confirm the biological and physical “Atlantification” of the Arctic Ocean with potential alterations of the Arctic marine food web and biogeochemical cycles. The North Atlantic current has been suspected to trigger intrusions of temperate marine species in the Arctic. Here, Oziel and colleagues reveal the link between the poleward intrusion of the temperate coccolithophore Emiliania huxleyi and the North Atlantic current, showing evidence for bio-advection as an important mechanism.
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11
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Ocean circulation causes the largest freshening event for 120 years in eastern subpolar North Atlantic. Nat Commun 2020; 11:585. [PMID: 31996687 PMCID: PMC6989661 DOI: 10.1038/s41467-020-14474-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Accepted: 12/04/2019] [Indexed: 12/03/2022] Open
Abstract
The Atlantic Ocean overturning circulation is important to the climate system because it carries heat and carbon northward, and from the surface to the deep ocean. The high salinity of the subpolar North Atlantic is a prerequisite for overturning circulation, and strong freshening could herald a slowdown. We show that the eastern subpolar North Atlantic underwent extreme freshening during 2012 to 2016, with a magnitude never seen before in 120 years of measurements. The cause was unusual winter wind patterns driving major changes in ocean circulation, including slowing of the North Atlantic Current and diversion of Arctic freshwater from the western boundary into the eastern basins. We find that wind-driven routing of Arctic-origin freshwater intimately links conditions on the North West Atlantic shelf and slope region with the eastern subpolar basins. This reveals the importance of atmospheric forcing of intra-basin circulation in determining the salinity of the subpolar North Atlantic. The Atlantic Ocean overturning circulation is important to the global climate system. Here the authors show that eastern subpolar North Atlantic underwent extreme freshening during 2012 to 2016, with a magnitude never seen before in 120 years of surface measurements.
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12
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Krause JW, Schulz IK, Rowe KA, Dobbins W, Winding MHS, Sejr MK, Duarte CM, Agustí S. Silicic acid limitation drives bloom termination and potential carbon sequestration in an Arctic bloom. Sci Rep 2019; 9:8149. [PMID: 31148569 PMCID: PMC6544819 DOI: 10.1038/s41598-019-44587-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2019] [Accepted: 05/17/2019] [Indexed: 11/09/2022] Open
Abstract
The spring diatom bloom in the Arctic Ocean accounts for significant annual primary production leading to the most rapid annual drawdown of water-column pCO2. Late-winter waters in the Atlantic Arctic & Subarctic Provinces (AASP) have lower silicic acid concentrations than nitrate, which suggests diatom blooms may deplete Si before N. Here we test a facet of the hypothesis that silicic acid limitation terminates the spring diatom bloom in the AASP and the sinking of the senescent and dead diatoms helps drive carbon sequestration. During a 6-week study, diatoms bloomed and progressively consumed silicic acid to where it limited their growth. The onset of growth limitation was concurrent with the minimum pCO2 in the surface waters and increases in both the proportion of dead diatoms and the diatom assemblage sedimentation rate. Data reanalysis within the AASP shows a highly significant and positive correlation between silicic acid and pCO2 in the surface waters, but no significant relationship with nitrate and pCO2 was observed unless data were smoothed. Therefore, understanding the future of the AASP spring diatom bloom requires models that explicitly consider changes in silicic acid supply as a driver of this process.
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Affiliation(s)
- Jeffrey W Krause
- Dauphin Island Sea Lab, Dauphin Island, AL, USA. .,Department of Marine Sciences, University of South Alabama, Mobile, AL, USA.
| | - Isabelle K Schulz
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Katherine A Rowe
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | | | - Mie H S Winding
- Greenland Climate Research Centre, Greenland Institute of Natural Resources, Nuuk, Greenland
| | - Mikael K Sejr
- Arctic Research Center (ARC), Aarhus University, Aarhus, Denmark
| | - Carlos M Duarte
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.,Arctic Research Center (ARC), Aarhus University, Aarhus, Denmark
| | - Susana Agustí
- Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
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13
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Gardarsson A, Jónsson JE. Numbers and distribution of the Great Cormorant in Iceland: Limitation at the regional and metapopulation level. Ecol Evol 2019; 9:3984-4000. [PMID: 31015982 PMCID: PMC6468091 DOI: 10.1002/ece3.5028] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 02/05/2019] [Accepted: 02/08/2019] [Indexed: 11/10/2022] Open
Abstract
We studied a metapopulation of great cormorant (Phalacrocorax carbo) in Iceland, using complete aerial censuses of nests in 25 years during 1975-2015. Age composition was estimated in 1998-2014 by ground surveys in September and February. Brood size was estimated from aerial photographs in 2007-2015.Weather, food, breeding habitat, and density were considered as explanatory variables when examining numerical and distributional changes in the cormorant metapopulation.In 1975-1990 total nest numbers changed little, very low numbers about 1992 were followed by an annual increase of 3.5% in 1994-2015. Total nest numbers were positively correlated with estimates of spawning stocks of cod and saithe and inversely related to the subpolar gyre index (SPG-I).During the increase in 1994-2015, average colony size at first increased and then declined. Habitat use also changed: the proportion of nests on small rocky islets (skerries) at first declined, from 69% to 44% in 1995-2003 and then increased again to about 58% in 2012-2014. Habitat changes were probably a response to changed patterns of human disturbance.Breeding density, as nests per km2 sea <20 m deep, was rather uniform among five defined regions in 1975-1996. Thereafter, densities became much higher in two sheltered regions with kelp forests and in one mostly exposed region. A second exposed region remained low and in the third nest numbers declined markedly. Thus, carrying capacity was higher in sheltered regions where cormorant breeding had historically been depressed by human disturbance.Brood size varied little among regions but declined with the years from about 2.5 to 1.8.The proportion of juveniles in September (fecundity) declined in 1998-2015 from over 0.4 to 0.3 and was inversely correlated with year and nest numbers, if outlier years were excluded, suggesting resource limitation. Survival of juvenile cormorants in September-February was estimated at 0.471 ± 0.066 SE. Commercial fish stocks and climate indices were not correlated with the proportion of juveniles.Annual survival of adults (breeding and nonbreeding) was estimated from nest counts and age composition 1999-2014, as 0.850 ± 0.026 SE and showed no trend in 1998-2014.We conclude that the metapopulation of cormorants in Iceland was resource-limited at two levels: fecundity at the regional and winter survival at the total level.
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Affiliation(s)
- Arnthor Gardarsson
- Institute of Biological and Environmental SciencesUniversity of IcelandReykjavikIceland
| | - Jón Einar Jónsson
- Research Centre at SnæfellsnesUniversity of IcelandStykkishólmurIceland
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