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Grimes M, Carrivick JL, Smith MW, Comber AJ. Land cover changes across Greenland dominated by a doubling of vegetation in three decades. Sci Rep 2024; 14:3120. [PMID: 38351020 PMCID: PMC10864356 DOI: 10.1038/s41598-024-52124-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2023] [Accepted: 01/14/2024] [Indexed: 02/16/2024] Open
Abstract
Land cover responses to climate change must be quantified for understanding Arctic climate, managing Arctic water resources, maintaining the health and livelihoods of Arctic societies and for sustainable economic development. This need is especially pressing in Greenland, where climate changes are amongst the most pronounced of anywhere in the Arctic. Ice loss from the Greenland Ice Sheet and from glaciers and ice caps has increased since the 1980s and consequently the proglacial parts of Greenland have expanded rapidly. Here we determine proglacial land cover changes at 30 m spatial resolution across Greenland during the last three decades. Besides the vastly decreased ice cover (- 28,707 km2 ± 9767 km2), we find a doubling in total areal coverage of vegetation (111% ± 13%), a quadrupling in wetlands coverage (380% ± 29%), increased meltwater (15% ± 15%), decreased bare bedrock (- 16% ± 4%) and increased coverage of fine unconsolidated sediment (4% ± 13%). We identify that land cover change is strongly associated with the difference in the number of positive degree days, especially above 6 °C between the 1980s and the present day. Contrastingly, absolute temperature increase has a negligible association with land cover change. We explain that these land cover changes represent local rapid and intense geomorphological activity that has profound consequences for land surface albedo, greenhouse gas emissions, landscape stability and sediment delivery, and biogeochemical processes.
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Affiliation(s)
- Michael Grimes
- School of Geography and Water@Leeds, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK.
| | - Jonathan L Carrivick
- School of Geography and Water@Leeds, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Mark W Smith
- School of Geography and Water@Leeds, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
| | - Alexis J Comber
- School of Geography and Water@Leeds, University of Leeds, Woodhouse Lane, Leeds, LS2 9JT, UK
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2
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Migała K, Łupikasza E, Osuch M, Opała-Owczarek M, Owczarek P. Linking drought indices to atmospheric circulation in Svalbard, in the Atlantic sector of the High Arctic. Sci Rep 2024; 14:2160. [PMID: 38272941 PMCID: PMC10810796 DOI: 10.1038/s41598-024-51869-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 01/10/2024] [Indexed: 01/27/2024] Open
Abstract
Based on long-term climatological data from Ny-Ålesund, Svalbard Airport-Longyearbyen and the Polish Polar Station at Hornsund, we undertook an analysis of drought indices on Spitsbergen Island, Svalbard, for the period 1979-2019. The features and causes of spatiotemporal variability of atmospheric drought in Svalbard were identified, as expressed by the standardized precipitation evapotranspiration index (SPEI). There were several-year periods with SPEI indicating the dominance of drought or wet conditions. The long-term variability in the annual and half-year (May-October) SPEI values showed a prevalence of droughts in the 1980s and the first decade of the twenty-first century, while wet seasons were frequent in the 1990s and in the second decade of the twenty-first century. The seasonal SPEIs were characteristic of interannual variability. In MAM and JJA, droughts were more frequent after 2000; during SON and DJF of the same period, the frequency of wet seasons increased. The most remarkable changes in the scale of the entire research period occurred in autumn when negative values of SPEI occurred more often in the first part of the period, and positive values dominated in the last 20 years. The long-term pattern of the variables in consecutive seasons between 1979 and 2019 indicates relationships between the SPEI and anomalies of precipitable water and somewhat weaker relationships with anomalies of sea level pressure. The three stations are located at distances of more than 200 km from each other in the northern (Ny-Ålesund), central (Longyearbyen) and southern parts of Svalbard (Hornsund), and the most extreme values of drought conditions depended on the atmospheric circulation which could have been modified by local conditions thus droughts developed under various circulation types depending on the station. However, some similarities were identified in the atmospheric circulation patterns favouring drought conditions at Ny-Ålesund and Hornsund, both having more maritime climates than Longyearbyen. Extremely dry seasons were favoured by anticyclonic conditions, particularly a high-pressure ridge (type Ka) centred over Svalbard, air advection from the eastern sector under an influence of cyclone and negative precipitable water anomalies. During wet seasons anomalies of precipitable water were positive and cyclonic conditions dominated. These results were corroborated by the frequency of regional circulation types during JJA and DJF with the lowest and highest values of SPEI.
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Affiliation(s)
- Krzysztof Migała
- Institute of Geography and Regional Development, University of Wroclaw, Pl. Uniwersytecki 1, 50-138, Wroclaw, Poland.
| | - Ewa Łupikasza
- Institute of Earth Sciences, University of Silesia in Katowice, ul. Będzińska 60, 41-200, Sosnowiec, Poland
| | - Marzena Osuch
- Institute of Geophysics, Polish Academy of Sciences, 64 Księcia Janusza Str., 01-452, Warsaw, Poland
| | - Magdalena Opała-Owczarek
- Institute of Earth Sciences, University of Silesia in Katowice, ul. Będzińska 60, 41-200, Sosnowiec, Poland
| | - Piotr Owczarek
- Institute of Geography and Regional Development, University of Wroclaw, Pl. Uniwersytecki 1, 50-138, Wroclaw, Poland
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3
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Garcia-Oteyza J, Giralt S, Pla-Rabes S, Antoniades D, Oliva M, Ghanbari H, Osorio-Serrano R, Palacios D. A ∼5000 year multiproxy record of summer climate in NE Greenland. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 906:167713. [PMID: 37827316 DOI: 10.1016/j.scitotenv.2023.167713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 09/29/2023] [Accepted: 10/08/2023] [Indexed: 10/14/2023]
Abstract
The High Arctic plays a vital role in Earth's climate system, and its ecosystems are highly sensitive to global climate change. High Arctic lakes are valuable sentinels of climate change, as their sediments integrate long-term natural climatic fluctuations and anthropogenic influences. Here, we present a high-resolution ∼5000 year-reconstruction of NE Greenland climate variability from Aucella Lake (74°N, 20°E) based on physical, chemical, and biological properties of lake sediments. We use CT-scans, hyperspectral imaging, organic matter, XRD, and diatom analyses to show that changing air temperatures were controlled by a mix of regional climatic changes and local landscape feedbacks. The latest Mid-Holocene (∼5.0-3.8 cal. ka BP) was characterized by relatively warmer conditions, while the onset of the Late-Holocene was marked by abrupt temperature decreases that coincided with the beginning of glacial advances elsewhere (∼3.8-3.4 cal. ka BP). From ∼3.4-2.4 cal. ka BP, the sedimentary record indicated progressive warming, with temperature peaking during the Medieval Climate Anomaly, although temperature rises were punctuated by abrupt, short-lived cold periods. From ∼1.1-0.05 cal. ka BP, the influence of landscape factors over the system diminished. Sedimentary indicators suggested a transition towards a colder, more humid climate, coinciding with the beginning of the Little Ice Age, that was characterized by a marked decrease in air temperature that reached minimum values at the end of this period. The last 50 years at Aucella Lake were marked by abrupt temperature rises, consistent with recently observed anthropogenic global warming. Our results illustrate the importance of high-resolution multiproxy studies for accurately characterizing lake linkages to their environment and climate.
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Affiliation(s)
- J Garcia-Oteyza
- Department of Geography, Universitat de Barcelona, Catalonia, Spain.
| | - S Giralt
- Geosciences Barcelona (GEO3BCN-CSIC), Spain
| | - S Pla-Rabes
- Universitat Autònoma de Barcelona, Bellaterra (Cerdanyola del Vallès), Catalonia, Spain; CREAF, Bellaterra (Cerdanyola del Vallès), Catalonia, Spain
| | - D Antoniades
- Department of Geography & Centre for Northern Studies, Laval University, Quebec, Canada
| | - M Oliva
- Department of Geography, Universitat de Barcelona, Catalonia, Spain
| | - H Ghanbari
- Department of Geography & Centre for Northern Studies, Laval University, Quebec, Canada
| | | | - D Palacios
- Department of Geography, Universidad Complutense de Madrid, Spain
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Stachnik Ł, Yde JC, Krzemień K, Uzarowicz Ł, Sitek S, Kenis P. SEM-EDS and water chemistry characteristics at the early stages of glacier recession reveal biogeochemical coupling between proglacial sediments and meltwater. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 835:155383. [PMID: 35452739 DOI: 10.1016/j.scitotenv.2022.155383] [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: 01/11/2022] [Revised: 04/12/2022] [Accepted: 04/14/2022] [Indexed: 06/14/2023]
Abstract
Most glaciers worldwide are undergoing climate-forced recession, but the impact of glacier changes on biogeochemical cycles is unclear. This study examines the influence of proglacial sediment weathering on meltwater chemistry at the early stages of glacier recession in the High Arctic of Svalbard. Scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDS) in combination with a wide range of geochemical analyses were used in this study. The SEM-EDS analyses of sediments collected in front of Werenskioldbreen show general degradation of pyrite and carbonate grains with age. The outer parts of pyrite grains have a gradual decrease in sulphur and gradual increase in iron oxides due to pyrite oxidation. This process was less advanced in the proglacial zone younger than 100 years compared to older sites such as the terminal moraine from the Little Ice Age. In both the proglacial zone and the terminal moraine, physical weathering of mineral grains, including formation of microcracks and microfractures, clearly enhanced pyrite oxidation. A consequence of proglacial sediment weathering is that the river chemistry is strongly affected by carbonate dissolution driven by sulphuric acid from sulphide oxidation. Also, reactive iron oxides, a product of sulphide oxidation, are mobilized in the proglacial zone. The results of this study show that proglacial weathering in the High Arctic of Svalbard is strongly coupled to river geochemistry, especially during the early stages of proglacial exposure after glacier recession.
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Affiliation(s)
- Łukasz Stachnik
- Department of Physical Geography, University of Wrocław, Wojciecha Cybulskiego Str. 34, 50-205 Wrocław, Poland; Western Norway University of Applied Sciences, Department of Environmental Sciences, Røyrgata 6, 6856 Sogndal, Norway; Jagiellonian University, Department of Geomorphology, Gronostajowa Str. 7, 30-387 Kraków, Poland.
| | - Jacob C Yde
- Western Norway University of Applied Sciences, Department of Environmental Sciences, Røyrgata 6, 6856 Sogndal, Norway.
| | - Kazimierz Krzemień
- Jagiellonian University, Department of Geomorphology, Gronostajowa Str. 7, 30-387 Kraków, Poland.
| | - Łukasz Uzarowicz
- Department of Soil Science, Institute of Agriculture, Warsaw University of Life Sciences - SGGW, Nowoursynowska Str. 159, Building 37, 02-776 Warsaw, Poland.
| | - Sławomir Sitek
- Institute of Earth Sciences, Faculty of Natural Sciences, University of Silesia in Katowice, Będzińska Str. 60, 41-200 Sosnowiec, Poland.
| | - Piotr Kenis
- Department of Physical Geography, University of Wrocław, Wojciecha Cybulskiego Str. 34, 50-205 Wrocław, Poland; Łukasiewicz Research Network, PORT Polish Centre for Technology Development, Electron Microscopy Laboratory, Stabłowicka St.147, 54-066 Wroclaw, Poland.
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5
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van Soest MAJ, Anderson NJ, Bol R, Dixon LR, Haygarth PM. Grazing and topography control nutrient pools in low Arctic soils of Southwest Greenland. EUROPEAN JOURNAL OF SOIL SCIENCE 2022; 73:e13278. [PMID: 36248184 PMCID: PMC9541922 DOI: 10.1111/ejss.13278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 06/18/2022] [Accepted: 06/29/2022] [Indexed: 06/16/2023]
Abstract
Soil nutrient pools in the dry low Arctic are likely to be released under climatic change and this bioavailability has the potential to increase both terrestrial and aquatic productions. As well as the direct effect of warming, external disturbances such as nutrient deposition and grazing can also drive ecosystem change. This study in the low Arctic Kangerlussuaq area of southwest Greenland compared soil nutrient pools in terms of both topographic position on a catena and by soil depth in two small catchments with contrasting muskox abundance. We tested the hypotheses that there were differences between soil carbon (C), nitrogen (N) and phosphorus (P) across a soil catena (ridge - slope - valley) and by soil depth (litter - 0-5 cm - 25-30 cm) for the two sites (SS17b, muskox present, versus - SS85, no muskox). Total C and N concentrations of soils were on average lower at SS17b compared to SS85. Moreover, the soil N concentration increased downslope in the catena with higher amounts in the valleys compared to the slopes and ridges. Soil P concentration (0.70 g P kg-1) was similar between catchments; however, litter P content was substantially different. The difference in soil nutrients between the two catchments was most likely due to the presence of muskox at SS17b, and hence grazing associated processes (defecation, altered microbiology and nutrient cycling). This study emphasises the heterogeneity of arctic landscapes and need for ecosystem specific research. Highlights Soil nutrient pools in two low-arctic catchments in Greenland were compared.Grazing and dung inputs by muskox affect soil nutrient pools in Greenland.Soil P stores in Kangerlussuaq are similar to intensively managed farmland in Europe.The heterogeneity of arctic landscapes and need for ecosystem-specific research are emphasised.
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Affiliation(s)
- Maud A. J. van Soest
- Geography & EnvironmentLoughborough UniversityLoughboroughUK
- Present address:
Centre for Ecology and Hydrology, Environment Centre WalesBangorUK
| | - N. John Anderson
- Geography & EnvironmentLoughborough UniversityLoughboroughUK
- Department of Ecology and Environmental ScienceUmeå UniversityUmeåSweden
| | - Roland Bol
- Institute of Bio and Geosciences, Agrosphere (IBG‐3), Forschungszentrum Jülich GmbHJülichGermany
- School of Natural Sciences, Environment Centre WalesBangor UniversityBangorUK
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Landscape Controls on Nutrient Stoichiometry Regulate Lake Primary Production at the Margin of the Greenland Ice Sheet. Ecosystems 2021. [DOI: 10.1007/s10021-021-00693-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
AbstractGlobal change is reshaping the physical environment and altering nutrient dynamics across the Arctic. These changes can affect the structure and function of biological communities and influence important climate-related feedbacks (for example, carbon (C) sequestration) in biogeochemical processing hot spots such as lakes. To understand how these ecosystems will respond in the future, this study examined recent (< 10 y) and long-term (1000 y) shifts in autotrophic production across paraglacial environmental gradients in SW Greenland. Contemporary lake temperatures and light levels increased with distance from the ice sheet, along with dissolved organic C (DOC) concentrations and total nitrogen:total phosphorus (TN:TP) ratios. Diatom production measured as biogenic silica accumulation rates (BSiARs) and diatom contribution to microbial communities declined across these gradients, while total production estimated using C accumulation rates and δ13C increased, indicating that autochthonous production and C burial are controlled by microbial competition and competitive displacement across physiochemical gradients in the region. Diatom production was generally low across lakes prior to the 1800’s AD but has risen 1.5–3× above background levels starting between 1750 and 1880 AD. These increases predate contemporary regional warming by 115–250 years, and temperature stimulation of primary production was inconsistent with paleorecords for ~ 90% of the last millennium. Instead, primary production appeared to be more strongly related to N and P availability, which differs considerably across the region due to lake landscape position, glacial activity and degree of atmospheric nutrient deposition. These results suggest that biological responses to enhanced nutrient supply could serve as important negative feedbacks to global change.
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How P, Messerli A, Mätzler E, Santoro M, Wiesmann A, Caduff R, Langley K, Bojesen MH, Paul F, Kääb A, Carrivick JL. Greenland-wide inventory of ice marginal lakes using a multi-method approach. Sci Rep 2021; 11:4481. [PMID: 33627684 PMCID: PMC7904918 DOI: 10.1038/s41598-021-83509-1] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Accepted: 02/02/2021] [Indexed: 11/17/2022] Open
Abstract
Ice marginal lakes are a dynamic component of terrestrial meltwater storage at the margin of the Greenland Ice Sheet. Despite their significance to the sea level budget, local flood hazards and bigeochemical fluxes, there is a lack of Greenland-wide research into ice marginal lakes. Here, a detailed multi-sensor inventory of Greenland's ice marginal lakes is presented based on three well-established detection methods to form a unified remote sensing approach. The inventory consists of 3347 ([Formula: see text]%) ice marginal lakes ([Formula: see text]) detected for the year 2017. The greatest proportion of lakes lie around Greenland's ice caps and mountain glaciers, and the southwest margin of the ice sheet. Through comparison to previous studies, a [Formula: see text]% increase in lake frequency is evident over the west margin of the ice sheet since 1985. This suggests it is becoming increasingly important to include ice marginal lakes in future sea level projections, where these lakes will form a dynamic storage of meltwater that can influence outlet glacier dynamics. Comparison to existing global glacial lake inventories demonstrate that up to 56% of ice marginal lakes could be unaccounted for in global estimates of ice marginal lake change, likely due to the reliance on a single lake detection method.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Frank Paul
- Department of Geography, University of Zurich, Zurich, Switzerland
| | - Andreas Kääb
- Department of Geosciences, University of Oslo, Oslo, Norway
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Dane M, Anderson NJ, Osburn CL, Colbourne JK, Frisch D. Centennial clonal stability of asexual Daphnia in Greenland lakes despite climate variability. Ecol Evol 2020; 10:14178-14188. [PMID: 33391708 PMCID: PMC7771157 DOI: 10.1002/ece3.7012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2020] [Revised: 10/12/2020] [Accepted: 10/14/2020] [Indexed: 12/12/2022] Open
Abstract
Climate and environmental condition drive biodiversity at many levels of biological organization, from populations to ecosystems. Combined with paleoecological reconstructions, palaeogenetic information on resident populations provides novel insights into evolutionary trajectories and genetic diversity driven by environmental variability. While temporal observations of changing genetic structure are often made of sexual populations, little is known about how environmental change affects the long-term fate of asexual lineages. Here, we provide information on obligately asexual, triploid Daphnia populations from three Arctic lakes in West Greenland through the past 200-300 years to test the impact of environmental change on the temporal and spatial population genetic structure. The contrasting ecological state of the lakes, specifically regarding salinity and habitat structure may explain the observed lake-specific clonal composition over time. Palaeolimnological reconstructions show considerable regional environmental fluctuations since 1,700 (the end of the Little Ice Age), but the population genetic structure in two lakes was almost unchanged with at most two clones per time period. Their local populations were strongly dominated by a single clone that has persisted for 250-300 years. We discuss possible explanations for the apparent population genetic stability: (a) persistent clones are general-purpose genotypes that thrive under broad environmental conditions, (b) clonal lineages evolved subtle genotypic differences unresolved by microsatellite markers, or (c) epigenetic modifications allow for clonal adaptation to changing environmental conditions. Our results motivate research into the mechanisms of adaptation in these populations, as well as their evolutionary fate in the light of accelerating climate change in the polar regions.
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Affiliation(s)
- Maison Dane
- School of BiosciencesUniversity of BirminghamBirminghamUK
| | | | - Christopher L. Osburn
- Department of Marine, Earth, and Atmospheric SciencesNorth Carolina State UniversityRaleighNCUSA
| | | | - Dagmar Frisch
- School of BiosciencesUniversity of BirminghamBirminghamUK
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Burpee BT, Saros JE. Cross-ecosystem nutrient subsidies in Arctic and alpine lakes: implications of global change for remote lakes. ENVIRONMENTAL SCIENCE. PROCESSES & IMPACTS 2020; 22:1166-1189. [PMID: 32159183 DOI: 10.1039/c9em00528e] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Environmental change is continuing to affect the flow of nutrients, material and organisms across ecosystem boundaries. These cross-system flows are termed ecosystem subsidies. Here, we synthesize current knowledge of cross-ecosystem nutrient subsidies between remote lakes and their surrounding terrain, cryosphere, and atmosphere. Remote Arctic and alpine lakes are ideal systems to study the effects of cross ecosystem subsidies because (a) they are positioned in locations experiencing rapid environmental changes, (b) they are ecologically sensitive to even small subsidy changes, (c) they have easily defined ecosystem boundaries, and (d) a variety of standard methods exist that allow for quantification of lake subsidies and their impacts on ecological communities and ecosystem functions. We highlight similarities and differences between Arctic and alpine systems and identify current knowledge gaps to be addressed with future work. It is important to understand the dynamics of nutrient and material flows between lakes and their environments in order to improve our ability to predict ecosystem responses to continued environmental change.
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Affiliation(s)
- Benjamin T Burpee
- Climate Change Institute and School of Biology and Ecology, University of Maine, Orono, ME, USA.
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10
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Pastor A, Freixa A, Skovsholt LJ, Wu N, Romaní AM, Riis T. Microbial Organic Matter Utilization in High-Arctic Streams: Key Enzymatic Controls. MICROBIAL ECOLOGY 2019; 78:539-554. [PMID: 30739147 DOI: 10.1007/s00248-019-01330-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Accepted: 01/16/2019] [Indexed: 06/09/2023]
Abstract
In the Arctic, climate changes contribute to enhanced mobilization of organic matter in streams. Microbial extracellular enzymes are important mediators of stream organic matter processing, but limited information is available on enzyme processes in this remote area. Here, we studied the variability of microbial extracellular enzyme activity in high-Arctic fluvial biofilms. We evaluated 12 stream reaches in Northeast Greenland draining areas exhibiting different geomorphological features with contrasting contents of soil organic matter to cover a wide range of environmental conditions. We determined stream nitrogen, phosphorus, and dissolved organic carbon concentrations, quantified algal biomass and bacterial density, and characterized the extracellular enzyme activities involved in catalyzing the cleavage of a range of organic matter compounds (e.g., β-glucosidase, phosphatase, β-xylosidase, cellobiohydrolase, and phenol oxidase). We found significant differences in microbial organic matter utilization among the study streams draining contrasting geomorphological features, indicating a strong coupling between terrestrial and stream ecosystems. Phosphatase and phenol oxidase activities were higher in solifluction areas than in alluvial areas. Besides dissolved organic carbon, nitrogen availability was the main driver controlling enzyme activities in the high-Arctic, which suggests enhanced organic matter mineralization at increased nutrient availability. Overall, our study provides novel information on the controls of organic matter usage by high-Arctic stream biofilms, which is of high relevance due to the predicted increase of nutrient availability in high-Arctic streams in global climate change scenarios.
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Affiliation(s)
- Ada Pastor
- Department of Bioscience, Aarhus University, Ole Worms Allé 1, Aarhus, Denmark.
| | - Anna Freixa
- Catalan Institute for Water Research (ICRA), Girona, Spain
| | - Louis J Skovsholt
- Department of Bioscience, Aarhus University, Ole Worms Allé 1, Aarhus, Denmark
| | - Naicheng Wu
- Department of Bioscience, Aarhus University, Ole Worms Allé 1, Aarhus, Denmark
- Aarhus Institute of Advanced Studies, Aarhus University, Aarhus, Denmark
- Department of Health and Environmental Sciences, Xi'an Jiaotong-Liverpool University, Suzhou, China
| | - Anna M Romaní
- Institute of Aquatic Ecology, University of Girona, Girona, Spain
| | - Tenna Riis
- Department of Bioscience, Aarhus University, Ole Worms Allé 1, Aarhus, Denmark
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11
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Ren Z, Martyniuk N, Oleksy IA, Swain A, Hotaling S. Ecological Stoichiometry of the Mountain Cryosphere. Front Ecol Evol 2019. [DOI: 10.3389/fevo.2019.00360] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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12
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Anderson NJ, Appleby PG, Bindler R, Renberg I, Conley DJ, Fritz SC, Jones VJ, Whiteford EJ, Yang H. Landscape-Scale Variability of Organic Carbon Burial by SW Greenland Lakes. Ecosystems 2019. [DOI: 10.1007/s10021-019-00368-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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13
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The Role of Biological Soil Crusts in Nitrogen Cycling and Soil Stabilization in Kangerlussuaq, West Greenland. Ecosystems 2018. [DOI: 10.1007/s10021-018-0267-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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14
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McGowan S, Gunn HV, Whiteford EJ, John Anderson N, Jones VJ, Law AC. Functional attributes of epilithic diatoms for palaeoenvironmental interpretations in South-West Greenland lakes. JOURNAL OF PALEOLIMNOLOGY 2017; 60:273-298. [PMID: 30996516 PMCID: PMC6435045 DOI: 10.1007/s10933-017-9968-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Accepted: 04/28/2017] [Indexed: 06/09/2023]
Abstract
Benthic diatoms are commonly used for palaeoenvironmental reconstruction in Arctic regions, but interpretation of their ecology remains challenging. We studied epilithic diatom assemblages from the shallow margins of 19 lakes from three areas (coast-inland-ice sheet margin) along a climate gradient in Kangerlussuaq, West Greenland during two periods; shortly after ice-off (spring) and in the middle of the growth season (summer). We aimed to understand the distribution of Arctic epilithic diatoms in relation to water chemistry gradients during the two seasons, to investigate their incorporation into lake sediments and to assess their applicability as palaeoenvironmental indicators. Diatoms were correlated with nutrients in the spring and alkalinity/major ions in the summer, when nutrients were depleted; approximately half of the variance explained was independent of spatial factors. When categorised by functional attributes, diatom seasonal succession differed among regions with the most obvious changes in inland lakes where summer temperatures are warmer, organic nutrient processing is prevalent and silicate is limiting. These conditions led to small, motile and adnate diatoms being abundant in inland lakes during the summer (Nitzschia spp., Encyonopsis microcephala), as these functional attributes are suited to living within complex mats of non-siliceous microbial biofilms. Seasonal succession in silica-rich lakes at the coast was less pronounced and assemblages included Tabellaria flocculosa (indicating more acidic conditions) and Hannaea arcus (indicating input from inflowing rivers). The nitrogen-fixing diatom Epithemia sorex increased from the coast to the ice sheet, negatively correlating with a gradient of reactive nitrogen. The presence of this diatom in Holocene sediment records alongside cyanobacterial carotenoids during arid periods of low nitrogen delivery, suggests that it is a useful indicator of nitrogen limitation. Nitzschia species appear to be associated with high concentrations of organic carbon and heterotrophy, but their poor representation in West Greenland lake sediments due to taphonomic processes limits their palaeoenvironmental application in this region. Proportions of epilithic taxa in lake sediment records of coastal lakes increased during some wetter periods of the Holocene, suggesting that snowpack-derived nutrient delivery may offer diatom taxa living at lake margins a competitive advantage over planktonic diatoms during the "moating" ice melt period. Thus, further research investigating linkages between epilithic diatoms, snowpack and nutrient delivery in seasonally frozen lakes is recommended as these taxa live on the 'front-line' during the spring and may be especially sensitive to changes in snowmelt conditions.
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Affiliation(s)
- Suzanne McGowan
- School of Geography, University of Nottingham, University Park, Nottingham, NG7 2RD UK
- School of Geography, University of Nottingham, Malaysia Campus, 43500 Semenyih, Selangor Darul Ehsan Malaysia
| | - Hazel V. Gunn
- School of Geography, University of Nottingham, University Park, Nottingham, NG7 2RD UK
| | - Erika J. Whiteford
- Department of Geography, Loughborough University, Loughborough, LE11 3TU Leicestershire UK
| | - N. John Anderson
- Department of Geography, Loughborough University, Loughborough, LE11 3TU Leicestershire UK
| | - Vivienne J. Jones
- Environmental Change Research Centre, Department of Geography, University College London, Gower Street, London, WC1E 6BT UK
| | - Antonia C. Law
- School of Physical and Geographical Sciences, Keele University, William Smith Building, Keele, Staffs ST55BG UK
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