1
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Chen SC, Musat F, Richnow HH, Krüger M. Microbial diversity and oil biodegradation potential of northern Barents Sea sediments. J Environ Sci (China) 2024; 146:283-297. [PMID: 38969457 DOI: 10.1016/j.jes.2023.12.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 11/29/2023] [Accepted: 12/07/2023] [Indexed: 07/07/2024]
Abstract
The Arctic, an essential ecosystem on Earth, is subject to pronounced anthropogenic pressures, most notable being the climate change and risks of crude oil pollution. As crucial elements of Arctic environments, benthic microbiomes are involved in climate-relevant biogeochemical cycles and hold the potential to remediate upcoming contamination. Yet, the Arctic benthic microbiomes are among the least explored biomes on the planet. Here we combined geochemical analyses, incubation experiments, and microbial community profiling to detail the biogeography and biodegradation potential of Arctic sedimentary microbiomes in the northern Barents Sea. The results revealed a predominance of bacterial and archaea phyla typically found in the deep marine biosphere, such as Chloroflexi, Atribacteria, and Bathyarcheaota. The topmost benthic communities were spatially structured by sedimentary organic carbon, lacking a clear distinction among geographic regions. With increasing sediment depth, the community structure exhibited stratigraphic variability that could be correlated to redox geochemistry of sediments. The benthic microbiomes harbored multiple taxa capable of oxidizing hydrocarbons using aerobic and anaerobic pathways. Incubation of surface sediments with crude oil led to proliferation of several genera from the so-called rare biosphere. These include Alkalimarinus and Halioglobus, previously unrecognized as hydrocarbon-degrading genera, both harboring the full genetic potential for aerobic alkane oxidation. These findings increase our understanding of the taxonomic inventory and functional potential of unstudied benthic microbiomes in the Arctic.
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Affiliation(s)
- Song-Can Chen
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany; Division of Microbial Ecology, Department of Microbiology and Ecosystem Science, University of Vienna, Vienna, Austria
| | - Florin Musat
- Department of Biology, Section for Microbiology, Aarhus University, Aarhus, Denmark; Department of Molecular Biology and Biotechnology, Faculty of Biology and Geology, Babeș-Bolyai University, Cluj-Napoca, Romania.
| | - Hans-Hermann Richnow
- Department of Isotope Biogeochemistry, Helmholtz Centre for Environmental Research-UFZ, Leipzig, Germany
| | - Martin Krüger
- Federal Institute for Geosciences and Natural Resources (BGR), Stilleweg 2, 30655, Hannover, Germany
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2
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González-Herrero S, Navarro F, Pertierra LR, Oliva M, Dadic R, Peck L, Lehning M. Southward migration of the zero-degree isotherm latitude over the Southern Ocean and the Antarctic Peninsula: Cryospheric, biotic and societal implications. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:168473. [PMID: 38007123 DOI: 10.1016/j.scitotenv.2023.168473] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/06/2023] [Revised: 11/02/2023] [Accepted: 11/08/2023] [Indexed: 11/27/2023]
Abstract
The seasonal movement of the zero-degree isotherm across the Southern Ocean and Antarctic Peninsula drives major changes in the physical and biological processes around maritime Antarctica. These include spatial and temporal shifts in precipitation phase, snow accumulation and melt, thawing and freezing of the active layer of the permafrost, glacier mass balance variations, sea ice mass balance and changes in physiological processes of biodiversity. Here, we characterize the historical seasonal southward movement of the monthly near-surface zero-degree isotherm latitude (ZIL), and quantify the velocity of migration in the context of climate change using climate reanalyses and projections. From 1957 to 2020, the ZIL exhibited a significant southward shift of 16.8 km decade-1 around Antarctica and of 23.8 km decade-1 in the Antarctic Peninsula, substantially faster than the global mean velocity of temperature change of 4.2 km decade-1, with only a small fraction being attributed to the Southern Annular Mode (SAM). CMIP6 models reproduce the trends observed from 1957 to 2014 and predict a further southward migration around Antarctica of 24 ± 12 km decade-1 and 50 ± 19 km decade-1 under the SSP2-4.5 and SSP5-8.5 scenarios, respectively. The southward migration of the ZIL is expected to have major impacts on the cryosphere, especially on the precipitation phase, snow accumulation and in peripheral glaciers of the Antarctic Peninsula, with more uncertain changes on permafrost, ice sheets and shelves, and sea ice. Longer periods of temperatures above 0 °C threshold will extend active biological periods in terrestrial ecosystems and will reduce the extent of oceanic ice cover, changing phenologies as well as areas of productivity in marine ecosystems, especially those located on the sea ice edge.
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Affiliation(s)
- Sergi González-Herrero
- WSL Institute for Snow and Avalanche Research (SLF), Davos, Switzerland; Antarctic Group, Agencia Estatal de Meteorología (AEMET), Barcelona, Spain.
| | - Francisco Navarro
- Departmento de Matemática Aplicada a las TIC, ETSI de Telecomunicación, Universidad Politécnica de Madrid, Madrid, Spain
| | - Luis R Pertierra
- Plant & Soil Sciences Department, University of Pretoria, Pretoria, South Africa; Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), Universidad Católica de Chile, Santiago, Chile
| | - Marc Oliva
- Department of Geography, Universitat de Barcelona, Barcelona, Spain
| | - Ruzica Dadic
- WSL Institute for Snow and Avalanche Research (SLF), Davos, Switzerland
| | - Lloyd Peck
- British Antarctic Survey, UKRI-NERC, Cambridge, UK
| | - Michael Lehning
- WSL Institute for Snow and Avalanche Research (SLF), Davos, Switzerland; School of Architecture, Civil and Environmental Engineering, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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3
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Bliss AC. Passive microwave Arctic sea ice melt onset dates from the advanced horizontal range algorithm 1979-2022. Sci Data 2023; 10:857. [PMID: 38040706 PMCID: PMC10692222 DOI: 10.1038/s41597-023-02760-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2023] [Accepted: 11/17/2023] [Indexed: 12/03/2023] Open
Abstract
The onset of the summer melt season is a key stage of the Arctic sea ice seasonal cycle and is an indicator of climate change. Surface melting of the bare or snow-covered sea ice is detected using passive microwave satellite observations. The data set presented here is a 44 year record of Arctic sea ice annual melt onset (MO) dates for 1979-2022 produced using an updated version of the Advanced Horizontal Range Algorithm (AHRA). This data product contains annual maps of the sea ice MO date and a set of descriptive statistics summarizing the data. This paper describes a new update of the AHRA methodology, now AHRA V5, including key changes to the algorithm starting date and sea ice mask methodology to improve estimates of early-season MO dates especially near the sea ice periphery. AHRA V5 data are suitable for monitoring trends in Arctic and regional sea ice MO dates and for process studies of atmosphere-sea ice interactions during the early spring and summer months.
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Affiliation(s)
- Angela C Bliss
- NASA Goddard Space Flight Center, Cryospheric Sciences Laboratory, Greenbelt, Maryland, 20771, USA.
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4
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Anderson MA, Fisk AT, Laing R, Noël M, Angnatok J, Kirk J, Evans M, Pijogge L, Brown TM. Changing environmental conditions have altered the feeding ecology of two keystone Arctic marine predators. Sci Rep 2023; 13:14056. [PMID: 37640733 PMCID: PMC10462653 DOI: 10.1038/s41598-023-39091-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Accepted: 07/20/2023] [Indexed: 08/31/2023] Open
Abstract
Environmental change in the Arctic has impacted the composition and structure of marine food webs. Tracking feeding ecology changes of culturally-valued Arctic char (Salvelinus alpinus) and ringed seals (Pusa hispida) can provide an indication of the ecological significance of climate change in a vulnerable region. We characterized how changes in sea ice conditions, sea surface temperature (SST), and primary productivity affected the feeding ecology of these two keystone species over a 13- and 18-year period, respectively, in northern Labrador, Canada. Arctic char fed consistently on pelagic resources (δ13C) but shifted over time to feeding at a higher trophic level (δ15N) and on more marine/offshore resources (δ34S), which correlated with decreases in chlorophyll a concentration. A reduction in Arctic char condition factor and lipid content was associated with higher trophic position. Ringed seals also shifted to feeding at a higher trophic level, but on more pelagic resources, which was associated with lower SST and higher chlorophyll a concentrations. Years with abnormally high SSTs and reduced sea ice concentrations resulted in large isotopic niche sizes for both species, suggesting abrupt change can result in more variable feeding. Changes in abundance and distribution of species long valued by the Inuit of Labrador could diminish food security.
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Affiliation(s)
| | - Aaron T Fisk
- School of the Environment, University of Windsor, Windsor, ON, Canada
| | - Rodd Laing
- Nunatsiavut Government, Nain, NL, Canada
| | | | | | - Jane Kirk
- Environment and Climate Change Canada, Burlington, ON, Canada
| | - Marlene Evans
- Environment and Climate Change Canada, Saskatoon, SK, Canada
| | | | - Tanya M Brown
- School of the Environment, University of Windsor, Windsor, ON, Canada.
- Fisheries and Oceans Canada, West Vancouver, BC, Canada.
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5
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Hunnie BE, Schreiber L, Greer CW, Stern GA. The recalcitrance and potential toxicity of polycyclic aromatic hydrocarbons within crude oil residues in beach sediments at the BIOS site, nearly forty years later. ENVIRONMENTAL RESEARCH 2023; 222:115329. [PMID: 36693458 DOI: 10.1016/j.envres.2023.115329] [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: 04/09/2022] [Revised: 01/16/2023] [Accepted: 01/17/2023] [Indexed: 06/17/2023]
Abstract
The Arctic is a unique environment characterized by extreme conditions, including daylight patterns, sea ice cover, and some of the lowest temperatures on Earth. Such characteristics in tandem present challenges when extrapolating information from oil spill research within warmer, more temperate regions. Consequently, oil spill studies must be conducted within the Arctic to yield accurate and reliable results. Sites of the Baffin Island Oil Spill (BIOS) project (Cape Hatt, Baffin Island, Canadian Arctic) were revisited nearly 40 years after the original oil application to provide long-term monitoring data for Arctic oil spill research. Surface and subsurface sediment samples were collected from the intertidal zone of the 1981 nearshore oil spill experiment (Bay 11), from 1980 supratidal control plots (Crude Oil Point) and 1982 supratidal treatment plots (Bay 106). Samples were analyzed for Polycyclic Aromatic Hydrocarbons (PAHs) and alkylated homologues via Gas Chromatography - Mass Spectrometry (GC-MS). Our results suggest that total mean concentrations of all measured PAHs range from 0.049 to 14 mg/kg, whereas total mean concentrations of the 16 US EPA priority PAHs range from 0.02 to 2.1 mg/kg. The relative proportions of individual PAHs were compared between sampling sites and with the original technical mixture. Where available, percent loss of individual PAHs was compared with data from samples collected at the BIOS site, in 2001. All three sites featured samples where concentrations of various priority PAHs exceeded the established Interim Marine Sediment Quality Guidelines. All supratidal samples contained potentially toxic levels of PAHs. Even after nearly four decades of weathering, the recalcitrant crude oil residues remain a potential hazard for the native organisms. Continued monitoring of this unique study site is crucial for establishing a timeline for oil degradation, and to observe a reduction in toxicity over time.
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Affiliation(s)
- Blake E Hunnie
- University of Manitoba, 125 Dysart Rd, Winnipeg, MB R3T 2N2, Canada.
| | - Lars Schreiber
- National Research Council Canada, 6100 Royalmount Ave, Montreal, QC H4P 2R2, Canada.
| | - Charles W Greer
- National Research Council Canada, 6100 Royalmount Ave, Montreal, QC H4P 2R2, Canada; McGill University, Department of Natural Resource Sciences, 21111 Lakeshore Rd Ste-Anne-de-Bellevue, QC, H9X 3V9, Canada.
| | - Gary A Stern
- University of Manitoba, 125 Dysart Rd, Winnipeg, MB R3T 2N2, Canada.
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6
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The influence of recent and future climate change on spring Arctic cyclones. Nat Commun 2022; 13:6514. [PMID: 36351898 PMCID: PMC9646868 DOI: 10.1038/s41467-022-34126-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 10/13/2022] [Indexed: 11/11/2022] Open
Abstract
In recent decades, the Arctic has experienced rapid atmospheric warming and sea ice loss, with an ice-free Arctic projected by the end of this century. Cyclones are synoptic weather events that transport heat and moisture into the Arctic, and have complex impacts on sea ice, and the local and global climate. However, the effect of a changing climate on Arctic cyclone behavior remains poorly understood. This study uses high resolution (4 km), regional modeling techniques and downscaled global climate reconstructions and projections to examine how recent and future climatic changes alter cyclone behavior. Results suggest that recent climate change has not yet had an appreciable effect on Arctic cyclone characteristics. However, future sea ice loss and increasing surface temperatures drive large increases in the near-surface temperature gradient, sensible and latent heat fluxes, and convection during cyclones. The future climate can alter cyclone trajectories and increase and prolong intensity with greatly augmented wind speeds, temperatures, and precipitation. Such changes in cyclone characteristics could exacerbate sea ice loss and Arctic warming through positive feedbacks. The increasing extreme nature of these weather events has implications for local ecosystems, communities, and socio-economic activities.
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7
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Jones JM, Hildebrand JA, Thayre BJ, Jameson E, Small RJ, Wiggins SM. The influence of sea ice on the detection of bowhead whale calls. Sci Rep 2022; 12:8553. [PMID: 35595792 PMCID: PMC9122979 DOI: 10.1038/s41598-022-12186-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2021] [Accepted: 05/04/2022] [Indexed: 12/02/2022] Open
Abstract
Bowhead whales (Balaena mysticetus) face threats from diminishing sea ice and increasing anthropogenic activities in the Arctic. Passive acoustic monitoring is the most effective means for monitoring their distribution and population trends, based on the detection of their calls. Passive acoustic monitoring, however, is influenced by the sound propagation environment and ambient noise levels, which impact call detection probability. Modeling and simulations were used to estimate detection probability for bowhead whale frequency-modulated calls in the 80-180 Hz frequency band with and without sea ice cover and under various noise conditions. Sound transmission loss for bowhead calls is substantially greater during ice-covered conditions than during open-water conditions, making call detection ~ 3 times more likely in open-water. Estimates of daily acoustic detection probability were used to compensate acoustic detections for sound propagation and noise effects in two recording datasets in the northeast Chukchi Sea, on the outer shelf and continental slope, collected between 2012 and 2013. The compensated acoustic density suggests a decrease in whale presence with the retreat of sea ice at these recording sites. These results highlight the importance of accounting for effects of the environment on ambient noise and acoustic propagation when interpreting results of passive acoustic monitoring.
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Affiliation(s)
- Joshua M Jones
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92093-0205, USA.
| | - John A Hildebrand
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92093-0205, USA
| | - Bruce J Thayre
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92093-0205, USA
| | - Ellen Jameson
- University of San Diego, 5998 Alcala Park, San Diego, CA, 92110, USA
| | - Robert J Small
- Alaska Department of Fish and Game, 1255 W. 8th Street, Juneau, AK, 99811-5526, USA
| | - Sean M Wiggins
- Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, 92093-0205, USA
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8
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Physiographic Controls on Landfast Ice Variability from 20 Years of Maximum Extents across the Northwest Canadian Arctic. REMOTE SENSING 2022. [DOI: 10.3390/rs14092175] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Landfast ice is a defining feature among Arctic coasts, providing a critical transport route for communities and exerting control over the exposure of Arctic coasts to marine erosion processes. Despite its significance, there remains a paucity of data on the spatial variability of landfast ice and limited understanding of the environmental processes’ controls since the beginning of the 21st century. We present a new high spatiotemporal record (2000–2019) across the Northwest Canadian Arctic, using MODIS Terra satellite imagery to determine maximum landfast ice extent (MLIE) at the start of each melt season. Average MLIE across the Northwest Canadian Arctic declined by 73% in a direct comparison between the first and last year of the study period, but this was highly variable across regional to community scales, ranging from 14% around North Banks Island to 81% in the Amundsen Gulf. The variability was largely a reflection of 5–8-year cycles between landfast ice rich and poor periods with no discernible trend in MLIE. Interannual variability over the 20-year record of MLIE extent was more constrained across open, relatively uniform, and shallower sloping coastlines such as West Banks Island, in contrast with a more varied pattern across the numerous bays, headlands, and straits enclosed within the deep Amundsen Gulf. Static physiographic controls (namely, topography and bathymetry) were found to influence MLIE change across regional sites, but no association was found with dynamic environmental controls (storm duration, mean air temperature, and freezing and thawing degree day occurrence). For example, despite an exponential increase in storm duration from 2014 to 2019 (from 30 h to 140 h or a 350% increase) across the Mackenzie Delta, MLIE extents remained relatively consistent. Mean air temperatures and freezing and thawing degree day occurrences (over 1, 3, and 12-month periods) also reflected progressive northwards warming influences over the last two decades, but none showed a statistically significant relationship with MLIE interannual variability. These results indicate inferences of landfast ice variations commonly taken from wider sea ice trends may misrepresent more complex and variable sensitivity to process controls. The influences of different physiographic coastal settings need to be considered at process level scales to adequately account for community impacts and decision making or coastal erosion exposure.
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9
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Hauser DDW, Frost KJ, Burns JJ. Ringed seal (Pusa hispida) breeding habitat on the landfast ice in northwest Alaska during spring 1983 and 1984. PLoS One 2021; 16:e0260644. [PMID: 34843596 PMCID: PMC8629220 DOI: 10.1371/journal.pone.0260644] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 11/15/2021] [Indexed: 11/30/2022] Open
Abstract
There has been significant sea ice loss associated with climate change in the Pacific Arctic, with unquantified impacts to the habitat of ice-obligate marine mammals such as ringed seals (Pusa hispida). Ringed seals maintain breathing holes and excavate subnivean lairs on sea ice to provide protection from weather and predators during birthing, nursing, and resting. However, there is limited baseline information on the snow and ice habitat, distribution, density, and configuration of ringed seal structures (breathing holes, simple haul-out lairs, and pup lairs) in Alaska. Here, we describe historic field records from two regions of the eastern Chukchi Sea (Kotzebue Sound and Ledyard Bay) collected during spring 1983 and 1984 to quantify baseline ringed seal breeding habitat and map the distribution of ringed seal structures using modern geospatial tools. Of 490 structures located on pre-established study grids by trained dogs, 29% were pup lairs (25% in Kotzebue Sound and 33% in Ledyard Bay). Grids in Ledyard Bay had greater overall density of seal structures than those in Kotzebue Sound (8.6 structures/km2 and 7.1 structures/km2), but structures were larger in Kotzebue Sound. Pup lairs were located in closer proximity to other structures and characterized by deeper snow and greater ice deformation than haul-out lairs or simple breathing holes. At pup lairs, snow depths averaged 74.9 cm (range 37–132 cm), with ice relief nearby averaging 76 cm (range 31–183 cm), and ice deformation 29.9% (range 5–80%). We compare our results to similar studies conducted in other geographic regions and discuss our findings in the context of recent declines in extent and duration of seasonal cover of landfast sea ice and snow deposition on sea ice. Ultimately, additional research is needed to understand the effects of recent environmental changes on ringed seals, but our study establishes a baseline upon which future research can measure pup habitat in northwest Alaska.
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Affiliation(s)
- Donna D. W. Hauser
- International Arctic Research Center, University of Alaska Fairbanks, Fairbanks, Alaska, United States of America
- * E-mail:
| | - Kathryn J. Frost
- Alaska Department of Fish and Game (retired), Kailua Kona, Hawaii, United States of America
| | - John J. Burns
- Living Resources, Inc., Fairbanks, Alaska, United States of America
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10
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Borque-Espinosa A, Rode KD, Ferrero-Fernández D, Forte A, Capaccioni-Azzati R, Fahlman A. Subsurface swimming and stationary diving are metabolically cheap in adult Pacific walruses (Odobenus rosmarus divergens). J Exp Biol 2021; 224:273381. [PMID: 34746957 DOI: 10.1242/jeb.242993] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 11/02/2021] [Indexed: 11/20/2022]
Abstract
Walruses rely on sea-ice to efficiently forage and rest between diving bouts while maintaining proximity to prime foraging habitat. Recent declines in summer sea ice have resulted in walruses hauling out on land where they have to travel farther to access productive benthic habitat while potentially increasing energetic costs. Despite the need to better understand the impact of sea ice loss on energy expenditure, knowledge about metabolic demands of specific behaviours in walruses is scarce. In the present study, 3 adult female Pacific walruses (Odobenus rosmarus divergens) participated in flow-through respirometry trials to measure metabolic rates while floating inactive at the water surface during a minimum of 5 min, during a 180-second stationary dive, and while swimming horizontally underwater for ∼90 m. Metabolic rates during stationary dives (3.82±0.56 l O2 min-1) were lower than those measured at the water surface (4.64±1.04 l O2 min-1), which did not differ from rates measured during subsurface swimming (4.91±0.77 l O2 min-1). Thus, neither stationary diving nor subsurface swimming resulted in metabolic rates above those exhibited by walruses at the water surface. These results suggest that walruses minimize their energetic investment during underwater behaviours as reported for other marine mammals. Although environmental factors experienced by free-ranging walruses (e.g., winds or currents) likely affect metabolic rates, our results provide important information for understanding how behavioural changes affect energetic costs and can be used to improve bioenergetics models aimed at predicting the metabolic consequences of climate change on walruses.
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Affiliation(s)
- Alicia Borque-Espinosa
- Universitat de València, Av. de Blasco Ibáñez 13, 46010 Valencia, Spain.,Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain
| | - Karyn D Rode
- U.S. Geological Survey Alaska Science Center, , 4210 University Dr, Anchorage, 99508 AK, USA
| | | | - Anabel Forte
- Universitat de València, Av. de Blasco Ibáñez 13, 46010 Valencia, Spain
| | | | - Andreas Fahlman
- Fundación Oceanogràfic de la Comunitat Valenciana, Gran Vía Marqués del Turia 19, 46005 Valencia, Spain.,Global Diving Research, Inc. Ottawa, K2J 5E8 ON, Canada
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11
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Lindsay JM, Laidre KL, Conn PB, Moreland EE, Boveng PL. Modeling ringed seal Pusa hispida habitat and lair emergence timing in the eastern Bering and Chukchi Seas. ENDANGER SPECIES RES 2021. [DOI: 10.3354/esr01140] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Ringed seals Pusa hispida are reliant on snow and sea ice for denning, and a better understanding of ringed seal habitat selection and timing of emergence from snow dens (also called lairs) is needed to quantify and predict effects of climate change in the Arctic. We used generalized additive models to assess relationships between ringed seal counts, from spring aerial surveys in the Bering Sea (2012 and 2013) and Chukchi Sea (2016), and spatiotemporal covariates including survey date, remotely sensed snow and sea-ice values, and short-term weather data. We produced separate models for total ringed seal counts and for pup counts within each region. Our models showed that in both areas, total ringed seal counts increased over the course of the spring, especially after 15 May, indicating emergence from lairs and/or the onset of basking behavior. For the more northerly Chukchi Sea, we found a substantial unimodal effect of snow melt progression and a positive effect of snow depth on total ringed seal counts. In contrast, Bering Sea total ringed seal counts and pup counts in both regions were affected much more strongly by date than by habitat variables. Overall, our findings demonstrate that snow depth and melt play an important role in the timing of ringed seal den emergence, particularly in the Chukchi Sea, and suggest that ringed seal denning may be affected by continued shifts in melt and snow depth associated with climate change.
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Affiliation(s)
- JM Lindsay
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98105, USA
| | - KL Laidre
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98105, USA
- Polar Science Center, Applied Physics Laboratory, University of Washington, Seattle, WA 98105, USA
| | - PB Conn
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA 98115, USA
| | - EE Moreland
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA 98115, USA
| | - PL Boveng
- Marine Mammal Laboratory, Alaska Fisheries Science Center, National Marine Fisheries Service, National Oceanic and Atmospheric Administration, Seattle, WA 98115, USA
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12
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Evaluation of 2-m Air Temperature and Surface Temperature from ERA5 and ERA-I Using Buoy Observations in the Arctic during 2010–2020. REMOTE SENSING 2021. [DOI: 10.3390/rs13142813] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
In data-sparse regions such as the Arctic, atmospheric reanalysis is one of the key tools for understanding rapid climate change at the regional and global scales. The utility of reanalysis datasets based on data assimilation is affected by their accuracy and biases. Therefore, it is important to evaluate their performance. Here, we conduct inter-comparisons of two temperature variables, namely, the 2-m air temperature (Ta) and the surface temperature (Ts), from the widely used ERA-I and ERA5 reanalysis datasets provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) against in situ observations from three international buoy programs (i.e., the International Arctic Buoy Programme (IABP), the Multidisciplinary Drifting Observatory for the Study of Arctic Climate (MOSAiC), and the Cold Regions Research and Engineering Laboratory (CRREL)) during 2010–2020 in the Arctic. Overall, the results show that both the ERA-I and ERA5 were well correlated with the buoy observations, with the highest correlation coefficient reaching 0.98. There were generally warm Ta biases for both ERA-I (2.27 ± 3.33 °C) and ERA5 (2.34 ± 3.22 °C) when compared with more than 3000 matching pairs of daily buoy observations. The warm Ta biases of both reanalysis datasets exhibited seasonal variations, reaching the maximum of 3.73 ± 2.84 °C in April and the minimum of 1.36 ± 2.51 °C in September. For Ts, both ERA-I and ERA5 exhibited good consistencies with the buoy observations, but have higher amplitude biases compared with those for Ta, with generally negative biases of −4.79 ± 4.86 °C for ERA-I and −4.11 ± 3.92 °C for ERA5. For both reanalysis datasets, the largest bias of Ts (−11.18 ± 3.08 °C) occurred in December, while the biases were rather small (less than −3 °C) in the warmer months (April to October). The cold Ts biases for ERA-I and ERA5 were probably overestimated due to the location of the surface temperature sensors on the buoys, which may have been affected by snow cover. Both the Ta and Ts biases varied for different buoy programs and different sea ice concentration conditions, yet they exhibited similar trends.
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13
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Analysis of Sea Ice Timing and Navigability along the Arctic Northeast Passage from 2000 to 2019. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2021. [DOI: 10.3390/jmse9070728] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The ablation of Arctic sea ice makes seasonal navigation possible in the Arctic region, which accounted for the apparent influence of sea ice concentration in the navigation of the Arctic route. This paper uses Arctic sea ice concentration daily data from January 1, 2000, to December 31, 2019. We used a sea ice concentration threshold value of 40% to define the time window for navigating through the Arctic Northeast Passage (NEP). In addition, for the year when the navigation time of the NEP is relatively abnormal, we combined with wind field, temperature, temperature anomaly, sea ice age and sea ice movement data to analyze the sea ice conditions of the NEP and obtain the main factors affecting the navigation of the NEP. The results reveal the following: (1) The sea ice concentration of the NEP varies greatly seasonally. The best month for navigation is September. The opening time of the NEP varies from late July to early September, the end of navigation is concentrated in mid-October, and the navigation time is basically maintained at more than 30 days. (2) The NEP was not navigable in 2000, 2001, 2003 and 2004. The main factors are the high amount of multi-year ice, low temperature and the wind field blowing towards the Vilkitsky Strait and sea ice movement. The navigation time in 2012, 2015 and 2019 was longer, and the driving factors were the high temperature, weak wind and low amount of one-year ice. The navigation time in 2003, 2007 and 2013 was shorter, and the influencing factors were the strong wind field blowing towards the Vilkitsky Strait. (3) The key navigable areas of the NEP are the central part of the East Siberian Sea and the Vilkitsky Strait, and the Vilkitsky Strait has a greater impact on the NEP than the central part of the East Siberian Sea. The main reason for the high concentration of sea ice in the central part of the East Siberian Sea (2000 and 2001) was the large amount of multi-year ice. The main reason for the high concentration of sea ice in the Vilkitsky Strait (2000 to 2004 and 2007, 2013) was the strong offshore wind in summer, all of which were above 4 m s−1, pushing the sea ice near the Vilkitsky Strait to accumulate in the strait, thus affecting the opening of the NEP.
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Delay in Arctic Sea Ice Freeze-Up Linked to Early Summer Sea Ice Loss: Evidence from Satellite Observations. REMOTE SENSING 2021. [DOI: 10.3390/rs13112162] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The past decades have witnessed a rapid loss of the Arctic sea ice and a significant lengthening of the melt season. The years with the lowest summertime sea ice minimum were found to be accompanied by the latest freeze-up onset on record. Here, a synthetic approach is taken to examine the connections between sea ice melt timing and summer sea ice evolution from the remote sensing perspective. A 40-year (1979–2018) satellite-based time-series analysis shows that the date of autumn sea ice freeze-up is significantly correlated with the sea ice extent in early summer (r = −0.90, p < 0.01), while the spring melt onset is not a promising predictor of summer sea ice evolution. The delay in Arctic sea ice freeze-up (0.61 days year−1) in the Arctic was accompanied by a decline in surface albedo (absolute change of −0.13% year−1), an increase in net short-wave radiation (0.21 W m−2 year−1), and an increase in skin temperature (0.08 °C year−1) in summer. Sea ice loss would be the key reason for the delay in autumn freeze-up, especially in the Laptev, East-Siberian, Chukchi and Beaufort Seas, where sea ice has significantly declined throughout the summer, and strong correlations were found between the freeze-up onset and the solar radiation budget since early summer. This study highlights a connection between the summer sea ice melting and the autumn refreezing process through the ice-albedo feedback based on multisource satellite-based observations.
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Kim K, Park J, Jo N, Park S, Yoo H, Kim J, Lee SH. Monthly Variation in the Macromolecular Composition of Phytoplankton Communities at Jang Bogo Station, Terra Nova Bay, Ross Sea. Front Microbiol 2021; 12:618999. [PMID: 33643247 PMCID: PMC7905043 DOI: 10.3389/fmicb.2021.618999] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 01/21/2021] [Indexed: 11/17/2022] Open
Abstract
Organic carbon fixed by photosynthesis of phytoplankton during the polar growing period could be important for their survival and consumers during the long polar night. Differences in biochemical traits of phytoplankton between ice-free and polar night periods were investigated in biweekly water samples obtained at the Korean “Jang Bogo Station” located in Terra Nova Bay, Antarctica. The average concentration of total Chl-a from phytoplankton dominated by micro-sized species from the entire sampling period was 0.32 μg L–1 (SD = ± 0.88 μg L–1), with the highest concentration of 4.29 μg L–1 in February and the lowest concentration of 0.01 μg L–1 during the ice-covered polar night (April–October) in 2015. The highest protein concentration coincided with the peak Chl-a concentration in February and decreased rapidly relative to the carbohydrate and lipid concentrations in the early part of polar night. Among the different biochemical components, carbohydrates were the predominant constituent, accounting for 69% (SD = ± 14%) of the total particulate organic matter (POM) during the entire study period. The carbohydrate contributions to the total POM markedly increased from 39 ± 8% during the ice-free period to 73 ± 9% during the polar night period. In comparison, while we found a significant negative correlation (r2 = 0.92, p < 0.01) between protein contributions and carbohydrate contributions, lipid contributions did not show any particular trend with relatively small temporal variations during the entire observation period. The substantial decrease in the average weight ratio of proteins to carbohydrates from the ice-free period (mean ± SD = 1.0 ± 0.3) to the ice-covered period (mean ± SD = 0.1 ± 0.1) indicates a preferential loss of nitrogen-based proteins compared to carbohydrates during the polar night period. Overall, the average food material (FM) concentration and calorific contents of FM in this study were within the range reported previously from the Southern Ocean. The results from this study may serve as important background data for long-term monitoring of the regional and interannual variations in the physiological state and biochemical compositions of phytoplankton resulting from future climate change in Antarctica.
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Affiliation(s)
- Kwanwoo Kim
- Department of Oceanography, Pusan National University, Busan, South Korea
| | - Jisoo Park
- Division of Ocean Sciences, Korea Polar Research Institute, Incheon, South Korea
| | - Naeun Jo
- Department of Oceanography, Pusan National University, Busan, South Korea
| | - Sanghoon Park
- Department of Oceanography, Pusan National University, Busan, South Korea
| | - Hyeju Yoo
- Department of Oceanography, Pusan National University, Busan, South Korea
| | - Jaehong Kim
- Department of Oceanography, Pusan National University, Busan, South Korea
| | - Sang Heon Lee
- Department of Oceanography, Pusan National University, Busan, South Korea
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Fully Automated Detection of Supraglacial Lake Area for Northeast Greenland Using Sentinel-2 Time-Series. REMOTE SENSING 2021. [DOI: 10.3390/rs13020205] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The usability of multispectral satellite data for detecting and monitoring supraglacial meltwater ponds has been demonstrated for western Greenland. For a multitemporal analysis of large regions or entire Greenland, largely automated processing routines are required. Here, we present a sequence of algorithms that allow for an automated Sentinel-2 data search, download, processing, and generation of a consistent and dense melt pond area time-series based on open-source software. We test our approach for a ~82,000 km2 area at the 79 °N Glacier (Nioghalvfjerdsbrae) in northeast Greenland, covering the years 2016, 2017, 2018 and 2019. Our lake detection is based on the ratio of the blue and red visible bands using a minimum threshold. To remove false classification caused by the similar spectra of shadow and water on ice, we implement a shadow model to mask out topographically induced artifacts. We identified 880 individual lakes, traceable over 479 time-steps throughout 2016–2019, with an average size of 64,212 m2. Of the four years, 2019 had the most extensive lake area coverage with a maximum of 333 km2 and a maximum individual lake size of 30 km2. With 1.5 days average observation interval, our time-series allows for a comparison with climate data of daily resolution, enabling a better understanding of short-term climate-glacier feedbacks.
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17
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Synergistic interactions among growing stressors increase risk to an Arctic ecosystem. Nat Commun 2020; 11:6255. [PMID: 33288746 PMCID: PMC7721797 DOI: 10.1038/s41467-020-19899-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 10/29/2020] [Indexed: 11/08/2022] Open
Abstract
Oceans provide critical ecosystem services, but are subject to a growing number of external pressures, including overfishing, pollution, habitat destruction, and climate change. Current models typically treat stressors on species and ecosystems independently, though in reality, stressors often interact in ways that are not well understood. Here, we use a network interaction model (OSIRIS) to explicitly study stressor interactions in the Chukchi Sea (Arctic Ocean) due to its extensive climate-driven loss of sea ice and accelerated growth of other stressors, including shipping and oil exploration. The model includes numerous trophic levels ranging from phytoplankton to polar bears. We find that climate-related stressors have a larger impact on animal populations than do acute stressors like increased shipping and subsistence harvesting. In particular, organisms with a strong temperature-growth rate relationship show the greatest changes in biomass as interaction strength increased, but also exhibit the greatest variability. Neglecting interactions between stressors vastly underestimates the risk of population crashes. Our results indicate that models must account for stressor interactions to enable responsible management and decision-making.
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Sharma S, Blagrave K, Watson SR, O’Reilly CM, Batt R, Magnuson JJ, Clemens T, Denfeld BA, Flaim G, Grinberga L, Hori Y, Laas A, Knoll LB, Straile D, Takamura N, Weyhenmeyer GA. Increased winter drownings in ice-covered regions with warmer winters. PLoS One 2020; 15:e0241222. [PMID: 33206655 PMCID: PMC7673519 DOI: 10.1371/journal.pone.0241222] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 10/09/2020] [Indexed: 11/21/2022] Open
Abstract
Winter activities on ice are culturally important for many countries, yet they constitute a high safety risk depending upon the stability of the ice. Because consistently cold periods are required to form stable and thick ice, warmer winters could degrade ice conditions and increase the likelihood of falling through the ice. This study provides the first large-scale assessment of winter drowning from 10 Northern Hemisphere countries. We documented over 4000 winter drowning events. Winter drownings increased exponentially in regions with warmer winters when air temperatures neared 0°C. The largest number of drownings occurred when winter air temperatures were between -5°C and 0°C, when ice is less stable, and also in regions where indigenous traditions and livelihood require extended time on ice. Rates of drowning were greatest late in the winter season when ice stability declines. Children and adults up to the age of 39 were at the highest risk of winter drownings. Beyond temperature, differences in cultures, regulations, and human behaviours can be important additional risk factors. Our findings indicate the potential for increased human mortality with warmer winter air temperatures. Incorporating drowning prevention plans would improve adaptation strategies to a changing climate.
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Affiliation(s)
- Sapna Sharma
- Department of Biology, York University, Toronto, Ontario, Canada
- * E-mail:
| | - Kevin Blagrave
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Simon R. Watson
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Catherine M. O’Reilly
- Department of Geography, Geology, and The Environment, Illinois State University, Normal, Illinois, United States of America
| | - Ryan Batt
- Rutgers University, New Brunswick, New Jersey, United States of America
| | - John J. Magnuson
- Center for Limnology, University of Wisconsin-Madison, Madison, Wisconsin, United States of America
| | - Tessa Clemens
- Drowning Prevention Research Centre Canada, Toronto, Ontario, Canada
| | - Blaize A. Denfeld
- Department of Ecology and Environmental Science, Umeå University, Umeå, Sweden
| | - Giovanna Flaim
- Department of Sustainable Agro-ecosystems and Bioresources, Research and Innovation Centre, Fondazione Edmund Mach, San Michele all'Adige, Italy
| | - Laura Grinberga
- Department of Botany, The Latvian Museum of Natural History, Riga, Latvia
| | - Yukari Hori
- Department of Physical and Environmental Sciences, University of Toronto Scarborough, Toronto, Ontario, Canada
| | - Alo Laas
- Institute of Agricultural and Environmental Sciences, Estonian University of Life Sciences, Tartu, Estonia
| | - Lesley B. Knoll
- Itasca Biological Station and Laboratories, University of Minnesota Twin Cities, Lake Itasca, Minnesota, United States of America
| | - Dietmar Straile
- Limnological Institute, University of Konstanz, Konstanz, Germany
| | - Noriko Takamura
- Lake Biwa Branch Office, Center for Environmental Biology and Ecosystem Studies, National Institute for Environmental Studies, Otsu, Shiga, Japan
| | - Gesa A. Weyhenmeyer
- Department of Ecology and Genetics/Limnology, Uppsala University, Uppsala, Sweden
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Liston GE, Itkin P, Stroeve J, Tschudi M, Stewart JS, Pedersen SH, Reinking AK, Elder K. A Lagrangian Snow-Evolution System for Sea-Ice Applications (SnowModel-LG): Part I-Model Description. JOURNAL OF GEOPHYSICAL RESEARCH. OCEANS 2020; 125:e2019JC015913. [PMID: 33133995 PMCID: PMC7583384 DOI: 10.1029/2019jc015913] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 07/31/2020] [Accepted: 08/05/2020] [Indexed: 06/11/2023]
Abstract
A Lagrangian snow-evolution model (SnowModel-LG) was used to produce daily, pan-Arctic, snow-on-sea-ice, snow property distributions on a 25 × 25-km grid, from 1 August 1980 through 31 July 2018 (38 years). The model was forced with NASA's Modern Era Retrospective-Analysis for Research and Applications-Version 2 (MERRA-2) and European Centre for Medium-Range Weather Forecasts (ECMWF) ReAnalysis-5th Generation (ERA5) atmospheric reanalyses, and National Snow and Ice Data Center (NSIDC) sea ice parcel concentration and trajectory data sets (approximately 61,000, 14 × 14-km parcels). The simulations performed full surface and internal energy and mass balances within a multilayer snowpack evolution system. Processes and features accounted for included rainfall, snowfall, sublimation from static-surfaces and blowing-snow, snow melt, snow density evolution, snow temperature profiles, energy and mass transfers within the snowpack, superimposed ice, and ice dynamics. The simulations produced horizontal snow spatial structures that likely exist in the natural system but have not been revealed in previous studies spanning these spatial and temporal domains. Blowing-snow sublimation made a significant contribution to the snowpack mass budget. The superimposed ice layer was minimal and decreased over the last four decades. Snow carryover to the next accumulation season was minimal and sensitive to the melt-season atmospheric forcing (e.g., the average summer melt period was 3 weeks or 50% longer with ERA5 forcing than MERRA-2 forcing). Observed ice dynamics controlled the ice parcel age (in days), and ice age exerted a first-order control on snow property evolution.
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Affiliation(s)
- Glen E. Liston
- Cooperative Institute for Research in the Atmosphere (CIRA)Colorado State UniversityFort CollinsCOUSA
| | - Polona Itkin
- Department of Physics and TechnologyUiT The Arctic University of NorwayTromsøNORWAY
| | - Julienne Stroeve
- Earth SciencesUniversity College LondonLondonUK
- National Snow and Ice Data Center (NSIDC)University of Colorado BoulderBoulderCOUSA
| | - Mark Tschudi
- Colorado Center for Astrodynamics Research (CCAR)University of Colorado BoulderBoulderCOUSA
| | - J. Scott Stewart
- Colorado Center for Astrodynamics Research (CCAR)University of Colorado BoulderBoulderCOUSA
| | - Stine H. Pedersen
- Cooperative Institute for Research in the Atmosphere (CIRA)Colorado State UniversityFort CollinsCOUSA
- Department of Biological SciencesUniversity of Alaska AnchorageAnchorageAKUSA
| | - Adele K. Reinking
- Cooperative Institute for Research in the Atmosphere (CIRA)Colorado State UniversityFort CollinsCOUSA
| | - Kelly Elder
- Rocky Mountain Research StationUSDA Forest ServiceFort CollinsCOUSA
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Estimating Meltwater Drainage Onset Timing and Duration of Landfast Ice in the Canadian Arctic Archipelago Using AMSR-E Passive Microwave Data. REMOTE SENSING 2020. [DOI: 10.3390/rs12061033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Meltwater drainage onset (DO) timing and drainage duration (DD) related to snowmelt-water redistribution are both important for understanding not only the Arctic energy and heat budgets but also the salt/heat balance of the mixed layer in the ocean and sea-ice ecosystem. We present DO and DD as determined from the time series of Advanced Microwave Scanning Radiometer-Earth observing system (AMSR-E) melt pond fraction (MPF) estimates in an area with Canadian landfast ice. To address the lack of evaluation on a day-by-day basis for the AMSR-E MPF estimate, we first compared AMSR-E MPF with the daily Medium Resolution Imaging Spectrometer (MERIS) MPF. The AMSR-E MPF estimate correlates significantly with the MERIS MPF (r = 0.73–0.83). The estimate has a product quality similar to the MERIS MPF only when the albedo is around 0.5–0.7 and a positive bias of up to 10% in areas with an albedo of 0.7–0.9, including melting snow. The DO/DD estimates are determined by using a polynomial regression curve fitted on the time series of the AMSR-E MPF. The DOs/DDs from time series of the AMSR-E and MERIS MPFs are compared, revealing consistency in both DD and DO. The DO timing from 2006 to 2011 is correlated with melt onset timing. To the best of our knowledge, our study provides the first large-scale information on both DO timing and DD.
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Toulkeridis T, Tamayo E, Simón-Baile D, Merizalde-Mora MJ, Reyes –Yunga DF, Viera-Torres M, Heredia M. Climate Change according to Ecuadorian academics–Perceptions versus facts. ACTA ACUST UNITED AC 2020. [DOI: 10.17163/lgr.n31.2020.02] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
Climate change has become one of the most important topics in each country’s government agendas. The current effects demand quicker actions in order to decrease the speed at which the global warming and climate is changing, which are commonly seen in global agreements to reduce pollution. However, the main changes to face and mitigate such phenomena depends on each country´s decision and not on global agreements as the causes are continent-wide although the effects and magnitudes may be local. One of the key components for an effective adaption and mitigation is the role that the population have over national decisions. For this reason, the level of awareness and knowledge about what is occurring in their surroundings vital, thus the importance of a correct information broadcast and education. For the aforementioned reasons, the current study compares the recent perception of a well-educated Ecuadorean community regarding the climate change worldwide and in Ecuador with the scientific evidence and historical facts, and how it affects its vulnerability to the climate change effects.
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Spatial and Temporal Variations in the Extent and Thickness of Arctic Landfast Ice. REMOTE SENSING 2019. [DOI: 10.3390/rs12010064] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Analyses of landfast ice in Arctic coastal areas provide a comprehensive understanding of the variations in Arctic sea ice and generate data for studies on the utilization of the Arctic passages. Based on our analysis, Arctic landfast ice mainly appears in January–June and is distributed within the narrow straits of the Canadian Archipelago (nearly 40%), the coastal areas of the East Siberian Sea, the Laptev Sea, and the Kara Sea. From 1976–2018, the landfast ice extent gradually decreased at an average rate of −1.1 ± 0.5 × 104 km2/yr (10.5% per decade), while the rate of decrease for entire Arctic sea ice was −6.0 ± 2.4 × 104 km2/yr (5.2% per decade). The annual maximum extent reached 2.3 × 106 km2 in the early 1980s, and by 2018, the maximum extent decreased by 0.6 × 106 km2, which is an area approximately equivalent the Laptev Sea. The mean duration of Arctic landfast ice is 44 weeks, which has gradually been reduced at a rate of −0.06 ± 0.03 weeks/yr. Regional landfast ice extent decreases in 16 of the 17 subregions except for the Bering Sea, making it the only subregion where both the extent and duration increases. The maximum mean landfast ice thickness appears in the northern Canadian Archipelago (>2.5 m), with the highest increasing trend (0.1 m/yr). In the Northeast Passage, the mean landfast ice thickness is 1.57 m, with a slight decreasing trend of −1.2 cm/yr, which is smaller than that for entire Arctic sea ice (−5.1 cm/yr). The smaller decreasing trend in the landfast ice extent and thickness suggests that the well-known Arctic sea ice decline largely occurred in the pack ice zone, while the larger relative extent loss indicates a faster ice free future in the landfast ice zone.
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Kochnev AA. Phenology of the Pacific Walrus (Odobenus rosmarus divergens) in Coastal Waters of Wrangel Island: The Impact of the Sea Ice Dynamics. BIOL BULL+ 2019. [DOI: 10.1134/s1062359019090061] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Yu Y, Taylor PC, Cai M. Seasonal Variations of Arctic Low-Level Clouds and Its Linkage to Sea Ice Seasonal Variations. JOURNAL OF GEOPHYSICAL RESEARCH. ATMOSPHERES : JGR 2019; 124:12206-12226. [PMID: 32025450 PMCID: PMC6988461 DOI: 10.1029/2019jd031014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2019] [Revised: 11/01/2019] [Accepted: 11/04/2019] [Indexed: 06/10/2023]
Abstract
Using CALIPSO-CloudSat-Clouds and the Earth's Radiant Energy System-Moderate Resolution Imaging Spectrometer data set, this study documents the seasonal variation of sea ice, cloud, and atmospheric properties in the Arctic (70°N-82°N) for 2007-2010. A surface-type stratification-consisting Permanent Ocean, Land, Permanent Ice, and Transient Sea Ice-is used to investigate the influence of surface type on low-level Arctic cloud liquid water path (LWP) seasonality. The results show significant variations in the Arctic low-level cloud LWP by surface type linked to differences in thermodynamic state. Subdividing the Transient Ice region (seasonal sea ice zone) by melt/freeze season onset dates reveals a complex influence of sea ice variations on low cloud LWP seasonality. We find that lower tropospheric stability is the primary factor affecting the seasonality of cloud LWP. Our results suggest that variations in sea ice melt/freeze onset have a significant influence on the seasonality of low-level cloud LWP by modulating the lower tropospheric thermal structure and not by modifying the surface evaporation rate in late spring and midsummer. We find no significant dependence of the May low-level cloud LWP peak on the melt/freeze onset dates, whereas and September/October low-level cloud LWP maximum shifts later in the season for earlier melt/later freeze onset regions. The Arctic low cloud LWP seasonality is controlled by several surface-atmosphere interaction processes; the importance of each varies seasonally due to the thermodynamic properties of sea ice. Our results demonstrate that when analyzing Arctic cloud-sea ice interactions, a seasonal perspective is critical.
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Affiliation(s)
- Yueyue Yu
- Key Laboratory of Meteorological Disaster, Ministry of Education (KLME)/Joint International Research Laboratory of Climate and Environment Change (ILCEC)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters (CIC‐FEMD)/NUIST‐UoR International Research InstituteNanjing University of Information Science and TechnologyNanjingChina
| | | | - Ming Cai
- Department of Earth, Ocean & Atmospheric SciencesFlorida State UniversityTallahasseeFLUSA
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The role of cyclone activity in snow accumulation on Arctic sea ice. Nat Commun 2019; 10:5285. [PMID: 31754115 PMCID: PMC6872656 DOI: 10.1038/s41467-019-13299-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2019] [Accepted: 10/30/2019] [Indexed: 12/02/2022] Open
Abstract
Identifying the mechanisms controlling the timing and magnitude of snow accumulation on sea ice is crucial for understanding snow’s net effect on the surface energy budget and sea-ice mass balance. Here, we analyze the role of cyclone activity on the seasonal buildup of snow on Arctic sea ice using model, satellite, and in situ data over 1979–2016. On average, 44% of the variability in monthly snow accumulation was controlled by cyclone snowfall and 29% by sea-ice freeze-up. However, there were strong spatio-temporal differences. Cyclone snowfall comprised ~50% of total snowfall in the Pacific compared to 83% in the Atlantic. While cyclones are stronger in the Atlantic, Pacific snow accumulation is more sensitive to cyclone strength. These findings highlight the heterogeneity in atmosphere-snow-ice interactions across the Arctic, and emphasize the need to scrutinize mechanisms governing cyclone activity to better understand their effects on the Arctic snow-ice system with anthropogenic warming. Snow cover can affect the Arctic sea-ice system in different ways. Here authors study the relationship between cyclone activity and the seasonal build-up of snow on Arctic sea ice at a multi-decadal and basin-wide scale and find that 44% of the variability in monthly snow accumulation was controlled by cyclone snowfall and 29% by sea-ice freeze-up with strong spatio-temporal differences.
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Reynolds RA, Stramski D. Optical characterization of marine phytoplankton assemblages within surface waters of the western Arctic Ocean. LIMNOLOGY AND OCEANOGRAPHY 2019; 64:2478-2496. [PMID: 31894158 PMCID: PMC6919934 DOI: 10.1002/lno.11199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/07/2019] [Revised: 04/17/2019] [Accepted: 04/29/2019] [Indexed: 06/10/2023]
Abstract
An extensive data set of measurements within the Chukchi and Beaufort Seas is used to characterize the optical properties of seawater associated with different phytoplankton communities. Hierarchical cluster analysis of diagnostic pigment concentrations partitioned stations into four distinct surface phytoplankton communities based on taxonomic composition and average cell size. Concurrent optical measurements of spectral absorption and backscattering coefficients and remote-sensing reflectance were used to characterize the magnitudes and spectral shapes of seawater optical properties associated with each phytoplankton assemblage. The results demonstrate measurable differences among communities in the average spectral shapes of the phytoplankton absorption coefficient. Similar or smaller differences were also observed in the spectral shapes of nonphytoplankton absorption coefficients and the particulate backscattering coefficient. Phytoplankton on average, however, contributed only 25% or less to the total absorption coefficient of seawater. Our analyses indicate that the interplay between the magnitudes and relative contributions of all optically significant constituents generally dampens any influence of varying phytoplankton absorption spectral shapes on the total absorption coefficient, yet there is still a marked discrimination observed in the spectral shape of the ratio of the total backscattering to total absorption coefficient and remote-sensing reflectance among the phytoplankton assemblages. These spectral variations arise mainly from differences in the bio-optical environment in which specific communities were found, as opposed to differences in the spectral shapes of phytoplankton optical properties per se. These results suggest potential approaches for the development of algorithms to assess phytoplankton community composition from measurements of seawater optical properties in western Arctic waters.
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Affiliation(s)
- Rick A. Reynolds
- Marine Physical LaboratoryScripps Institution of Oceanography, University of California San DiegoLa JollaCalifornia
| | - Dariusz Stramski
- Marine Physical LaboratoryScripps Institution of Oceanography, University of California San DiegoLa JollaCalifornia
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Cusset F, Fort J, Mallory M, Braune B, Massicotte P, Massé G. Arctic seabirds and shrinking sea ice: egg analyses reveal the importance of ice-derived resources. Sci Rep 2019; 9:15405. [PMID: 31659198 PMCID: PMC6817817 DOI: 10.1038/s41598-019-51788-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Accepted: 10/05/2019] [Indexed: 11/09/2022] Open
Abstract
In the Arctic, sea-ice plays a central role in the functioning of marine food webs and its rapid shrinking has large effects on the biota. It is thus crucial to assess the importance of sea-ice and ice-derived resources to Arctic marine species. Here, we used a multi-biomarker approach combining Highly Branched Isoprenoids (HBIs) with δ13C and δ15N to evaluate how much Arctic seabirds rely on sea-ice derived resources during the pre-laying period, and if changes in sea-ice extent and duration affect their investment in reproduction. Eggs of thick-billed murres (Uria lomvia) and northern fulmars (Fulmarus glacialis) were collected in the Canadian Arctic during four years of highly contrasting ice conditions, and analysed for HBIs, isotopic (carbon and nitrogen) and energetic composition. Murres heavily relied on ice-associated prey, and sea-ice was beneficial for this species which produced larger and more energy-dense eggs during icier years. In contrast, fulmars did not exhibit any clear association with sympagic communities and were not impacted by changes in sea ice. Murres, like other species more constrained in their response to sea-ice variations, therefore appear more sensitive to changes and may become the losers of future climate shifts in the Arctic, unlike more resilient species such as fulmars.
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Affiliation(s)
- Fanny Cusset
- UMI Takuvik, Département de Biologie, Université Laval, 1045 Avenue de la Médecine, Québec, QC, G1V 0A6, Canada.
| | - Jérôme Fort
- LIENSs, UMR 7266, CNRS-La Rochelle Université, 2 Rue Olympe de Gouges, 17000, La Rochelle, France
| | - Mark Mallory
- Biology Department, Acadia University, 15 University Avenue, Wolfville, NS, B4P 2R6, Canada
| | - Birgit Braune
- Environment and Climate Change Canada, National Wildlife Research Centre, Carleton University, Raven Road, Ottawa, ON, K1A 0H3, Canada
| | - Philippe Massicotte
- UMI Takuvik, Département de Biologie, Université Laval, 1045 Avenue de la Médecine, Québec, QC, G1V 0A6, Canada
| | - Guillaume Massé
- UMI Takuvik, Département de Biologie, Université Laval, 1045 Avenue de la Médecine, Québec, QC, G1V 0A6, Canada.,LOCEAN, UMR 7159, CNRS, MNHN, IRD, Sorbonne-Université, Station Marine de Concarneau, BP225, 29900, Concarneau, France
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Assessing Spatiotemporal Variations of Landsat Land Surface Temperature and Multispectral Indices in the Arctic Mackenzie Delta Region between 1985 and 2018. REMOTE SENSING 2019. [DOI: 10.3390/rs11192329] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Air temperatures in the Arctic have increased substantially over the last decades, which has extensively altered the properties of the land surface. Capturing the state and dynamics of Land Surface Temperatures (LSTs) at high spatial detail is of high interest as LST is dependent on a variety of surficial properties and characterizes the land–atmosphere exchange of energy. Accordingly, this study analyses the influence of different physical surface properties on the long-term mean of the summer LST in the Arctic Mackenzie Delta Region (MDR) using Landsat 30 m-resolution imagery between 1985 and 2018 by taking advantage of the cloud computing capabilities of the Google Earth Engine. Multispectral indices, including the Normalized Difference Vegetation Index (NDVI), Normalized Difference Water Index (NDWI) and Tasseled Cap greenness (TCG), brightness (TCB), and wetness (TCW) as well as topographic features derived from the TanDEM-X digital elevation model are used in correlation and multiple linear regression analyses to reveal their influence on the LST. Furthermore, surface alteration trends of the LST, NDVI, and NDWI are revealed using the Theil-Sen (T-S) regression method. The results indicate that the mean summer LST appears to be mostly influenced by the topographic exposition as well as the prevalent moisture regime where higher evapotranspiration rates increase the latent heat flux and cause a cooling of the surface, as the variance is best explained by the TCW and northness of the terrain. However, fairly diverse model outcomes for different regions of the MDR (R2 from 0.31 to 0.74 and RMSE from 0.51 °C to 1.73 °C) highlight the heterogeneity of the landscape in terms of influential factors and suggests accounting for a broad spectrum of different factors when modeling mean LSTs. The T-S analysis revealed large-scale wetting and greening trends with a mean decadal increase of the NDVI/NDWI of approximately +0.03 between 1985 and 2018, which was mostly accompanied by a cooling of the land surface given the inverse relationship between mean LSTs and vegetation and moisture conditions. Disturbance through wildfires intensifies the surface alterations locally and lead to significantly cooler LSTs in the long-term compared to the undisturbed surroundings.
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Gao C, Lin S, Chen M, Hong J, Liu C. Prevalence of phycotoxin contamination in shellfish from the Northern Bering Sea and the Chukchi Sea. Toxicon 2019; 167:76-81. [DOI: 10.1016/j.toxicon.2019.06.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2018] [Revised: 04/25/2019] [Accepted: 06/03/2019] [Indexed: 10/26/2022]
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Passive Microwave Melt Onset Retrieval Based on a Variable Threshold: Assessment in the Canadian Arctic Archipelago. REMOTE SENSING 2019. [DOI: 10.3390/rs11111304] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The Canadian Arctic Archipelago (CAA) presents unique challenges to the determination of melt onset (MO) using remote sensing data. High spatial resolution data is required to discern melt onset among the islands and narrow waterways of the region. Current passive microwave retrievals use daily averaged 19 GHz and 37 GHz data from the multi-channel microwave radiometer (SMMR) and/or the special sensor microwave/imager (SSM/I). The development of a new passive microwave melt onset method capable of using higher resolution data is desirable. The new passive microwave melt onset method described here, named the Dynamic Threshold Variability Method (DTVM), uses higher resolution data from the 37 GHz vertically-polarized channel from the advanced microwave scanning radiometers (AMSR-E and AMSR-2). The DTVM MO detection methodology differs from previously presented passive microwave Arctic MO methods in that it does not use a fixed threshold of a brightness temperature parameter. Instead, the DTVM determines MO dates based on the distribution of dates corresponding to the exceedance of a range of brightness temperature variability thresholds. The method also uses swath data instead of daily averaged brightness temperatures, which is found to lead to improved melt detection. Two current passive microwave MO methods are compared and evaluated for applicability in the CAA alongside the DTVM. The DTVM provides MO dates at a higher spatial resolution than earlier methods in addition to higher correlation with MO dates from surface air temperature (SAT) reanalyses. It is found that, for some years, MO dates in the CAA exhibit a latitudinal dependence, while in other years the MO dates in the CAA are relatively uniform across the domain.
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Arctic warming interrupts the Transpolar Drift and affects long-range transport of sea ice and ice-rafted matter. Sci Rep 2019; 9:5459. [PMID: 30940829 PMCID: PMC6445075 DOI: 10.1038/s41598-019-41456-y] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2018] [Accepted: 03/08/2019] [Indexed: 11/16/2022] Open
Abstract
Sea ice is an important transport vehicle for gaseous, dissolved and particulate matter in the Arctic Ocean. Due to the recently observed acceleration in sea ice drift, it has been assumed that more matter is advected by the Transpolar Drift from shallow shelf waters to the central Arctic Ocean and beyond. However, this study provides first evidence that intensified melt in the marginal zones of the Arctic Ocean interrupts the transarctic conveyor belt and has led to a reduction of the survival rates of sea ice exported from the shallow Siberian shelves (−15% per decade). As a consequence, less and less ice formed in shallow water areas (<30 m) has reached Fram Strait (−17% per decade), and more ice and ice-rafted material is released in the northern Laptev Sea and central Arctic Ocean. Decreasing survival rates of first-year ice are visible all along the Russian shelves, but significant only in the Kara Sea, East Siberian Sea and western Laptev Sea. Identified changes affect biogeochemical fluxes and ecological processes in the central Arctic: A reduced long-range transport of sea ice alters transport and redistribution of climate relevant gases, and increases accumulation of sediments and contaminates in the central Arctic Ocean, with consequences for primary production, and the biodiversity of the Arctic Ocean.
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How Much Do Clouds Mask the Impacts of Arctic Sea Ice and Snow Cover Variations? Different Perspectives from Observations and Reanalyses. ATMOSPHERE 2019. [DOI: 10.3390/atmos10010012] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Decreasing sea ice and snow cover are reducing the surface albedo and changing the Arctic surface energy balance. How these surface albedo changes influence the planetary albedo is a more complex question, though, that depends critically on the modulating effects of the intervening atmosphere. To answer this question, we partition the observed top of atmosphere (TOA) albedo into contributions from the surface and atmosphere, the latter being heavily dependent on clouds. While the surface albedo predictably declines with lower sea ice and snow cover, the TOA albedo decreases approximately half as much. This weaker response can be directly attributed to the fact that the atmosphere contributes more than 70% of the TOA albedo in the annual mean and is less dependent on surface cover. The surface accounts for a maximum of 30% of the TOA albedo in spring and less than 10% by the end of summer. Reanalyses (ASR versions 1 and 2, ERA-Interim, MERRA-2, and NCEP R2) represent the annual means of surface albedo fairly well, but biases are found in magnitudes of the TOA albedo and its contributions, likely due to their representations of clouds. Reanalyses show a wide range of TOA albedo sensitivity to changing sea ice concentration, 0.04–0.18 in September, compared to 0.11 in observations.
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Halliday W, Pine M, Insley S, Soares R, Kortsalo P, Mouy X. Acoustic detections of Arctic marine mammals near Ulukhaktok, Northwest Territories, Canada. CAN J ZOOL 2019. [DOI: 10.1139/cjz-2018-0077] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The Arctic marine environment is changing rapidly through a combination of sea ice loss and increased anthropogenic activity. Given these changes can affect marine animals in a variety of ways, understanding the spatial and temporal distributions of Arctic marine animals is imperative. We use passive acoustic monitoring to examine the presence of marine mammals near Ulukhaktok, Northwest Territories, Canada, from October 2016 to April 2017. We documented bowhead whale (Balaena mysticetus Linnaeus, 1758) and beluga whale (Delphinapterus leucas (Pallas, 1776)) vocalizations later into the autumn than expected, and we recorded bowhead whales in early April. We recorded ringed seal (Pusa hispida (Schreber, 1775)) vocalizations throughout our deployment, with higher vocal activity than in other studies and with peak vocal activity in January. We recorded bearded seals (Erignathus barbatus (Erxleben, 1777)) throughout the deployment, with peak vocal activity in February. We recorded lower bearded seal vocal activity than other studies, and almost no vocal activity near the beginning of the spring breeding season. Both seal species vocalized more when ice concentration was high. These patterns in vocal activity document the presence of each species at this site over autumn and winter and are a useful comparison for future monitoring.
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Affiliation(s)
- W.D. Halliday
- Wildlife Conservation Society Canada, 169 Titanium Way, Whitehorse, YT Y1A 0E9, Canada
- Department of Biology, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada
| | - M.K. Pine
- Wildlife Conservation Society Canada, 169 Titanium Way, Whitehorse, YT Y1A 0E9, Canada
- Department of Biology, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada
| | - S.J. Insley
- Wildlife Conservation Society Canada, 169 Titanium Way, Whitehorse, YT Y1A 0E9, Canada
- Department of Biology, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada
| | - R.N. Soares
- Wildlife Conservation Society Canada, 169 Titanium Way, Whitehorse, YT Y1A 0E9, Canada
| | - P. Kortsalo
- Wildlife Conservation Society Canada, 169 Titanium Way, Whitehorse, YT Y1A 0E9, Canada
| | - X. Mouy
- School of Earth and Ocean Sciences, University of Victoria, 3800 Finnerty Road, Victoria, BC V8P 5C2, Canada
- JASCO Applied Science Ltd., 2305-4464 Markham Street, Victoria, BC V8Z 7X8, Canada
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Wang T, Liu D, Piao S, Wang Y, Wang X, Guo H, Lian X, Burkhart JF, Ciais P, Huang M, Janssens I, Li Y, Liu Y, Peñuelas J, Peng S, Yang H, Yao Y, Yin Y, Zhao Y. Emerging negative impact of warming on summer carbon uptake in northern ecosystems. Nat Commun 2018; 9:5391. [PMID: 30568168 PMCID: PMC6300666 DOI: 10.1038/s41467-018-07813-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Accepted: 10/31/2018] [Indexed: 11/10/2022] Open
Abstract
Most studies of the northern hemisphere carbon cycle based on atmospheric CO2 concentration have focused on spring and autumn, but the climate change impact on summer carbon cycle remains unclear. Here we used atmospheric CO2 record from Point Barrow (Alaska) to show that summer CO2 drawdown between July and August, a proxy of summer carbon uptake, is significantly negatively correlated with terrestrial temperature north of 50°N interannually during 1979-2012. However, a refined analysis at the decadal scale reveals strong differences between the earlier (1979-1995) and later (1996-2012) periods, with the significant negative correlation only in the later period. This emerging negative temperature response is due to the disappearance of the positive temperature response of summer vegetation activities that prevailed in the earlier period. Our finding, together with the reported weakening temperature control on spring carbon uptake, suggests a diminished positive effect of warming on high-latitude carbon uptake.
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Affiliation(s)
- Tao Wang
- Center for Excellence in Tibetan Earth Science, Chinese Academy of Sciences, Beijing, 100085, China. .,Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100085, China.
| | - Dan Liu
- Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100085, China
| | - Shilong Piao
- Center for Excellence in Tibetan Earth Science, Chinese Academy of Sciences, Beijing, 100085, China.,Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100085, China.,Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Yilong Wang
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE, Gif-sur-Yvette, F-91191, France
| | - Xiaoyi Wang
- Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100085, China
| | - Hui Guo
- Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100085, China
| | - Xu Lian
- Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - John F Burkhart
- Department of Geosciences, University of Oslo, Oslo, 0371, Norway
| | - Philippe Ciais
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE, Gif-sur-Yvette, F-91191, France
| | - Mengtian Huang
- Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Ivan Janssens
- Department of Biology, University of Antwerp, Universiteitsplein 1, 2610, Wilrijk, Belgium
| | - Yue Li
- Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Yongwen Liu
- Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Josep Peñuelas
- CREAF, Cerdanyola del Valles, Barcelona, 08193, Catalonia, Spain.,CSIC, Global Ecology Unit CREAF-CEAB-CSIC-UAB, Cerdanyola del Valles, Barcelona, 08193, Catalonia, Spain
| | - Shushi Peng
- Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Hui Yang
- Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Yitong Yao
- Sino-French Institute for Earth System Science, College of Urban and Environmental Sciences, Peking University, Beijing, 100871, China
| | - Yi Yin
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE, Gif-sur-Yvette, F-91191, France
| | - Yutong Zhao
- Key Laboratory of Alpine Ecology, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100085, China
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35
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Precursors of September Arctic Sea-Ice Extent Based on Causal Effect Networks. ATMOSPHERE 2018. [DOI: 10.3390/atmos9110437] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Although standard statistical methods and climate models can simulate and predict sea-ice changes well, it is still very hard to distinguish some direct and robust factors associated with sea-ice changes from its internal variability and other noises. Here, with long-term observations (38 years from 1980 to 2017), we apply the causal effect networks algorithm to explore the direct precursors of September Arctic sea-ice extent by adjusting the maximal lead time from one to eight months. For lead time of more than three months, June downward longwave radiation flux in the Canadian Arctic Archipelago is the only one precursor. However, for lead time of 1–3 months, August sea-ice concentration in Western Arctic represents the strongest positive correlation with September sea-ice extent, while August sea-ice concentration factors in other regions have weaker influences on the marginal seas. Other precursors include August wind anomalies in the lower latitudes accompanied with an Arctic high pressure anomaly, which induces the sea-ice loss along the Eurasian coast. These robust precursors can be used to improve the seasonal predictions of Arctic sea ice and evaluate the climate models.
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36
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Horizontal and vertical distribution of polycystine radiolarians in the western Arctic Ocean during the late summers of 2013 and 2015. Polar Biol 2018. [DOI: 10.1007/s00300-018-2421-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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37
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The Role of Climate and Land Use in the Changes in Surface Albedo Prior to Snow Melt and the Timing of Melt Season of Seasonal Snow in Northern Land Areas of 40°N–80°N during 1982–2015. REMOTE SENSING 2018. [DOI: 10.3390/rs10101619] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The rapid warming of the Northern Hemisphere high latitudes and the observed changes in boreal forest areas affect the global surface albedo and climate. This study looks at the trends in the timing of the snow melt season as well as the albedo levels before and after the melt season in Northern Hemisphere land areas between 40°N and 80°N over the years 1982 to 2015. The analysis is based on optical satellite data from the Advanced Very High Resolution Radiometer (AVHRR). The results show that the changes in surface albedo already begin before the start of the melt season. These albedo changes are significant (the mean of absolute change is 4.4 albedo percentage units per 34 years). The largest absolute changes in pre-melt-season albedo are concentrated in areas of the boreal forest, while the pre-melt albedo of tundra remains unchanged. Trends in melt season timing are consistent over large areas. The mean of absolute change of start date of melt season is 11.2 days per 34 years, 10.6 days for end date of melt season and 14.8 days for length of melt season. The changes result in longer and shorter melt seasons, as well as changed timing of the melt, depending on the area. The albedo levels preceding the onset of melt and start of the melt season correlate with climatic parameters (air temperature, precipitation, wind speed). The changes in albedo are more closely linked to changes in vegetation, whereas the changes in melt season timing are linked to changes in climate.
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38
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Temporal Means and Variability of Arctic Sea Ice Melt and Freeze Season Climate Indicators Using a Satellite Climate Data Record. REMOTE SENSING 2018. [DOI: 10.3390/rs10091328] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Information on the timing of Arctic snow and ice melt onset, sea ice opening, retreat, advance, and closing, can be beneficial to a variety of stakeholders. Sea ice modelers can use information on the evolution of the ice cover through the rest of the summer to improve their seasonal sea ice forecasts. The length of the open water season (as derived from retreat/advance dates) is important for human activities and for wildlife. Long-term averages and variability of these dates as climate indicators are beneficial to business strategic planning and climate monitoring. In this study, basic characteristics of temporal means and variability of Arctic sea ice climate indicators derived from a satellite-based climate data record from March 1979 to February 2017 melt and freeze seasons are described. Our results show that, over the Arctic region, anomalies of snow and ice melt onset, ice opening and retreat dates are getting earlier in the year at a rate of more than 5 days per decade, while that of ice advance and closing dates are getting later at a rate of more than 5 days per decade. These significant trends resulted in significant upward trends for anomalies of inner and outer ice-free periods at a rate of nearly 12 days per decade. Small but significant downward trends of seasonal ice loss and gain period anomalies were also observed at a rate of −1.48 and −0.53 days per decade, respectively. Our analyses also demonstrated that the means of these indicators and their trends are sensitive to valid data masks and regional averaging methods.
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Woelders L, Lenaerts JTM, Hagemans K, Akkerman K, van Hoof TB, Hoek WZ. Recent climate warming drives ecological change in a remote high-Arctic lake. Sci Rep 2018; 8:6858. [PMID: 29717176 PMCID: PMC5931553 DOI: 10.1038/s41598-018-25148-7] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Accepted: 04/09/2018] [Indexed: 11/28/2022] Open
Abstract
The high Arctic is the fastest warming region on Earth, evidenced by extreme near-surface temperature increase in non-summer seasons, recent rapid sea ice decline and permafrost melting since the early 1990’s. Understanding the impact of climate change on the sensitive Arctic ecosystem to climate change has so far been hampered by the lack of time-constrained, high-resolution records and by implicit climate data analyses. Here, we show evidence of sharp growth in freshwater green algae as well as distinct diatom assemblage changes since ~1995, retrieved from a high-Arctic (80 °N) lake sediment record on Barentsøya (Svalbard). The proxy record approaches an annual to biennial resolution. Combining remote sensing and in-situ climate data, we show that this ecological change is concurrent with, and is likely driven by, the atmospheric warming and a sharp decrease in the length of the sea ice covered period in the region, and throughout the Arctic. Moreover, this research demonstrates the value of palaeoclimate records in pristine environments for supporting and extending instrumental records. Our results reinforce and extend observations from other sites that the high Arctic has already undergone rapid ecological changes in response to on-going climate change, and will continue to do so in the future.
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Affiliation(s)
- Lineke Woelders
- Department of Earth and Environmental Sciences, K.U. Leuven, Celestijnenlaan 200E, 3001, Leuven, Belgium. .,Institute of Arctic and Alpine Research, University of Colorado Boulder, Boulder, CO, United States of America.
| | - Jan T M Lenaerts
- Department of Atmospheric and Oceanic Sciences, University of Colorado Boulder, Boulder, CO, United States of America
| | - Kimberley Hagemans
- Department of Physical Geography, Faculty of Geosciences, Utrecht University, Princetonlaan 8A, 3584 CB, Utrecht, The Netherlands
| | - Keechy Akkerman
- Department of Earth Sciences, Faculty of Geosciences, Utrecht University, Princetonlaan 8A, 3584 CB, Utrecht, The Netherlands.,TNO Applied Geosciences, P.O. Box 80015, 3508 TA, Utrecht, The Netherlands.,Department of Geography, Loughborough University, Loughborough, LE11 3TU, United Kingdom
| | - Thomas B van Hoof
- TNO Applied Geosciences, P.O. Box 80015, 3508 TA, Utrecht, The Netherlands.,Deep-Time Consulting, Kroostweg 74, 3704 EG, Zeist, The Netherlands
| | - Wim Z Hoek
- Department of Physical Geography, Faculty of Geosciences, Utrecht University, Princetonlaan 8A, 3584 CB, Utrecht, The Netherlands
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40
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Changes in phytoplankton community structure during wind-induced fall bloom on the central Chukchi shelf. Polar Biol 2018. [DOI: 10.1007/s00300-018-2284-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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41
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Bluhm BA, Hop H, Vihtakari M, Gradinger R, Iken K, Melnikov IA, Søreide JE. Sea ice meiofauna distribution on local to pan-Arctic scales. Ecol Evol 2018; 8:2350-2364. [PMID: 29468049 PMCID: PMC5817141 DOI: 10.1002/ece3.3797] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 11/30/2017] [Accepted: 12/08/2017] [Indexed: 11/26/2022] Open
Abstract
Arctic sea ice provides microhabitats for biota that inhabit the liquid-filled network of brine channels and the ice-water interface. We used meta-analysis of 23 published and unpublished datasets comprising 721 ice cores to synthesize the variability in composition and abundance of sea ice meiofauna at spatial scales ranging from within a single ice core to pan-Arctic and seasonal scales. Two-thirds of meiofauna individuals occurred in the bottom 10 cm of the ice. Locally, replicate cores taken within meters of each other were broadly similar in meiofauna composition and abundance, while those a few km apart varied more; 75% of variation was explained by station. At the regional scale (Bering Sea first-year ice), meiofauna abundance varied over two orders of magnitude. At the pan-Arctic scale, the same phyla were found across the region, with taxa that have resting stages or tolerance to extreme conditions (e.g., nematodes and rotifers) dominating abundances. Meroplankton, however, was restricted to nearshore locations and landfast sea ice. Light availability, ice thickness, and distance from land were significant predictor variables for community composition on different scales. On a seasonal scale, abundances varied broadly for all taxa and in relation to the annual ice algal bloom cycle in both landfast and pack ice. Documentation of ice biota composition, abundance, and natural variability is critical for evaluating responses to decline in Arctic sea ice. Consistent methodology and protocols must be established for comparability of meiofauna monitoring across the Arctic. We recommend to (1) increase taxonomic resolution of sea ice meiofauna, (2) focus sampling on times of peak abundance when seasonal sampling is impossible, (3) include the bottom 30 cm of ice cores rather than only bottom 10 cm, (4) preserve specimens for molecular analysis to improve taxonomic resolution, and (5) formulate a trait-based framework that relates to ecosystem functioning.
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Affiliation(s)
- Bodil A. Bluhm
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
- College of Fisheries and Ocean SciencesUniversity of Alaska FairbanksFairbanksAKUSA
| | - Haakon Hop
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
- Norwegian Polar Institute, Fram CentreTromsøNorway
| | | | - Rolf Gradinger
- Department of Arctic and Marine BiologyFaculty of Biosciences, Fisheries and EconomicsUiT The Arctic University of NorwayTromsøNorway
| | - Katrin Iken
- College of Fisheries and Ocean SciencesUniversity of Alaska FairbanksFairbanksAKUSA
| | - Igor A. Melnikov
- Shirshov Institute of OceanologyRussian Academy of SciencesMoscowRussia
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On the Increasing Importance of Air-Sea Exchanges in a Thawing Arctic: A Review. ATMOSPHERE 2018. [DOI: 10.3390/atmos9020041] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Rode KD, Wilson RR, Douglas DC, Muhlenbruch V, Atwood TC, Regehr EV, Richardson ES, Pilfold NW, Derocher AE, Durner GM, Stirling I, Amstrup SC, St Martin M, Pagano AM, Simac K. Spring fasting behavior in a marine apex predator provides an index of ecosystem productivity. GLOBAL CHANGE BIOLOGY 2018; 24:410-423. [PMID: 28994242 DOI: 10.1111/gcb.13933] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 08/02/2017] [Indexed: 05/27/2023]
Abstract
The effects of declining Arctic sea ice on local ecosystem productivity are not well understood but have been shown to vary inter-specifically, spatially, and temporally. Because marine mammals occupy upper trophic levels in Arctic food webs, they may be useful indicators for understanding variation in ecosystem productivity. Polar bears (Ursus maritimus) are apex predators that primarily consume benthic and pelagic-feeding ice-associated seals. As such, their productivity integrates sea ice conditions and the ecosystem supporting them. Declining sea ice availability has been linked to negative population effects for polar bears but does not fully explain observed population changes. We examined relationships between spring foraging success of polar bears and sea ice conditions, prey productivity, and general patterns of ecosystem productivity in the Beaufort and Chukchi Seas (CSs). Fasting status (≥7 days) was estimated using serum urea and creatinine levels of 1,448 samples collected from 1,177 adult and subadult bears across three subpopulations. Fasting increased in the Beaufort Sea between 1983-1999 and 2000-2016 and was related to an index of ringed seal body condition. This change was concurrent with declines in body condition of polar bears and observed changes in the diet, condition and/or reproduction of four other vertebrate consumers within the food chain. In contrast, fasting declined in CS polar bears between periods and was less common than in the two Beaufort Sea subpopulations consistent with studies demonstrating higher primary productivity and maintenance or improved body condition in polar bears, ringed seals, and bearded seals despite recent sea ice loss in this region. Consistency between regional and temporal variation in spring polar bear fasting and food web productivity suggests that polar bears may be a useful indicator species. Furthermore, our results suggest that spatial and temporal ecological variation is important in affecting upper trophic-level productivity in these marine ecosystems.
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Affiliation(s)
- Karyn D Rode
- U.S. Geological Survey, Alaska Science Center, Anchorage, AK, USA
| | - Ryan R Wilson
- U.S. Fish and Wildlife Service, Marine Mammals Management, Anchorage, AK, USA
| | - David C Douglas
- U.S. Geological Survey, Alaska Science Center, Juneau, AK, USA
| | | | - Todd C Atwood
- U.S. Geological Survey, Alaska Science Center, Anchorage, AK, USA
| | - Eric V Regehr
- U.S. Fish and Wildlife Service, Marine Mammals Management, Anchorage, AK, USA
| | - Evan S Richardson
- Wildlife Research Division, Science and Technology Branch, Environment Canada, Edmonton, AB, Canada
| | - Nicholas W Pilfold
- Institute for Conservation Research, San Diego Zoo Global, Escondido, CA, USA
| | - Andrew E Derocher
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - George M Durner
- U.S. Geological Survey, Alaska Science Center, Anchorage, AK, USA
| | - Ian Stirling
- Wildlife Research Division, Science and Technology Branch, Environment Canada, Edmonton, AB, Canada
- Department of Biological Sciences, University of Alberta, Edmonton, AB, Canada
| | - Steven C Amstrup
- Polar Bears International, Bozeman, MT, USA
- Department of Zoology and Physiology, University of Wyoming, Laramie, WY, USA
| | - Michelle St Martin
- U.S. Fish and Wildlife Service, Marine Mammals Management, Anchorage, AK, USA
| | - Anthony M Pagano
- U.S. Geological Survey, Alaska Science Center, Anchorage, AK, USA
| | - Kristin Simac
- U.S. Geological Survey, Alaska Science Center, Anchorage, AK, USA
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Enhanced MODIS Atmospheric Total Water Vapour Content Trends in Response to Arctic Amplification. ATMOSPHERE 2017. [DOI: 10.3390/atmos8120241] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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45
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Implications of earlier sea ice melt for phenological cascades in arctic marine food webs. FOOD WEBS 2017. [DOI: 10.1016/j.fooweb.2016.11.002] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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46
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Mapping Radar Glacier Zones and Dry Snow Line in the Antarctic Peninsula Using Sentinel-1 Images. REMOTE SENSING 2017. [DOI: 10.3390/rs9111171] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Cao Y, Liang S, Chen X, He T, Wang D, Cheng X. Enhanced wintertime greenhouse effect reinforcing Arctic amplification and initial sea-ice melting. Sci Rep 2017; 7:8462. [PMID: 28814806 PMCID: PMC5559487 DOI: 10.1038/s41598-017-08545-2] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2016] [Accepted: 07/14/2017] [Indexed: 11/09/2022] Open
Abstract
The speeds of both Arctic surface warming and sea-ice shrinking have accelerated over recent decades. However, the causes of this unprecedented phenomenon remain unclear and are subjects of considerable debate. In this study, we report strong observational evidence, for the first time from long-term (1984-2014) spatially complete satellite records, that increased cloudiness and atmospheric water vapor in winter and spring have caused an extraordinary downward longwave radiative flux to the ice surface, which may then amplify the Arctic wintertime ice-surface warming. In addition, we also provide observed evidence that it is quite likely the enhancement of the wintertime greenhouse effect caused by water vapor and cloudiness has advanced the time of onset of ice melting in mid-May through inhibiting sea-ice refreezing in the winter and accelerating the pre-melting process in the spring, and in turn triggered the positive sea-ice albedo feedback process and accelerated the sea ice melting in the summer.
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Affiliation(s)
- Yunfeng Cao
- The College of Forestry, Beijing Forestry University, 100083, Beijing, China
| | - Shunlin Liang
- Department of Geographical Sciences, University of Maryland, 20742, College Park, USA.
| | - Xiaona Chen
- Department of Hydraulic Engineering, Tsinghua University, Beijing, China
| | - Tao He
- Department of Geographical Sciences, University of Maryland, 20742, College Park, USA
- School of Remote Sensing and Information Engineering, Wuhan University, Wuhan, Hubei, 430079, China
| | - Dongdong Wang
- Department of Geographical Sciences, University of Maryland, 20742, College Park, USA
| | - Xiao Cheng
- State Key Laboratory of Remote Sensing Science, and College of Global Change and Earth System Science, Beijing Normal University, 100875, Beijing, China
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Evidence for ice-ocean albedo feedback in the Arctic Ocean shifting to a seasonal ice zone. Sci Rep 2017; 7:8170. [PMID: 28811530 PMCID: PMC5557900 DOI: 10.1038/s41598-017-08467-z] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2016] [Accepted: 07/12/2017] [Indexed: 11/08/2022] Open
Abstract
Ice-albedo feedback due to the albedo contrast between water and ice is a major factor in seasonal sea ice retreat, and has received increasing attention with the Arctic Ocean shifting to a seasonal ice cover. However, quantitative evaluation of such feedbacks is still insufficient. Here we provide quantitative evidence that heat input through the open water fraction is the primary driver of seasonal and interannual variations in Arctic sea ice retreat. Analyses of satellite data (1979–2014) and a simplified ice-upper ocean coupled model reveal that divergent ice motion in the early melt season triggers large-scale feedback which subsequently amplifies summer sea ice anomalies. The magnitude of divergence controlling the feedback has doubled since 2000 due to a more mobile ice cover, which can partly explain the recent drastic ice reduction in the Arctic Ocean.
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Comparison of Passive Microwave-Derived Early Melt Onset Records on Arctic Sea Ice. REMOTE SENSING 2017. [DOI: 10.3390/rs9030199] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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