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Spatio-Temporal Variability of Suspended Particulate Matter in a High-Arctic Estuary (Adventfjorden, Svalbard) Using Sentinel-2 Time-Series. REMOTE SENSING 2022. [DOI: 10.3390/rs14133123] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Arctic coasts, which feature land-ocean transport of freshwater, sediments, and other terrestrial material, are impacted by climate change, including increased temperatures, melting glaciers, changes in precipitation and runoff. These trends are assumed to affect productivity in fjordic estuaries. However, the spatial extent and temporal variation of the freshwater-driven darkening of fjords remain unresolved. The present study illustrates the spatio-temporal variability of suspended particulate matter (SPM) in the Adventfjorden estuary, Svalbard, using in-situ field campaigns and ocean colour remote sensing (OCRS) via high-resolution Sentinel-2 imagery. To compute SPM concentration (CSPMsat), a semi-analytical algorithm was regionally calibrated using local in-situ data, which improved the accuracy of satellite-derived SPM concentration by ~20% (MRD). Analysis of SPM concentration for two consecutive years (2019, 2020) revealed strong seasonality of SPM in Adventfjorden. Highest estimated SPM concentrations and river plume extent (% of fjord with CSPMsat > 30 mg L−1) occurred during June, July, and August. Concurrently, we observed a strong relationship between river plume extent and average air temperature over the 24 h prior to the observation (R2 = 0.69). Considering predicted changes to environmental conditions in the Arctic region, this study highlights the importance of the rapidly changing environmental parameters and the significance of remote sensing in analysing fluxes in light attenuating particles, especially in the coastal Arctic Ocean.
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2
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Drivers of Turbidity and Its Seasonal Variability at Herschel Island Qikiqtaruk (Western Canadian Arctic). WATER 2022. [DOI: 10.3390/w14111751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The Arctic is greatly affected by climate change. Increasing air temperatures drive permafrost thaw and an increase in coastal erosion and river discharge. This results in a greater input of sediment and organic matter into nearshore waters, impacting ecosystems by reducing light transmission through the water column and altering biogeochemistry. This potentially results in impacts on the subsistence economy of local people as well as the climate due to the transformation of suspended organic matter into greenhouse gases. Even though the impacts of increased suspended sediment concentrations and turbidity in the Arctic nearshore zone are well-studied, the mechanisms underpinning this increase are largely unknown. Wave energy and tides drive the level of turbidity in the temperate and tropical parts of the world, and this is generally assumed to also be the case in the Arctic. However, the tidal range is considerably lower in the Arctic, and processes related to the occurrence of permafrost have the potential to greatly contribute to nearshore turbidity. In this study, we use high-resolution satellite imagery alongside in situ and ERA5 reanalysis data of ocean and climate variables in order to identify the drivers of nearshore turbidity, along with its seasonality in the nearshore waters of Herschel Island Qikiqtaruk, in the western Canadian Arctic. Nearshore turbidity correlates well to wind direction, wind speed, significant wave height, and wave period. Nearshore turbidity is superiorly correlated to wind speed at the Beaufort Shelf compared to in situ measurements at Herschel Island Qikiqtaruk, showing that nearshore turbidity, albeit being of limited spatial extent, is influenced by large-scale weather and ocean phenomenons. We show that, in contrast to the temperate and tropical ocean, freshly eroded material is the predominant driver of nearshore turbidity in the Arctic, rather than resuspension, which is caused by the vulnerability of permafrost coasts to thermo-erosion.
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Castellani G, Veyssière G, Karcher M, Stroeve J, Banas SN, Bouman AH, Brierley SA, Connan S, Cottier F, Große F, Hobbs L, Katlein C, Light B, McKee D, Orkney A, Proud R, Schourup-Kristensen V. Shine a light: Under-ice light and its ecological implications in a changing Arctic Ocean. AMBIO 2022; 51:307-317. [PMID: 34822117 PMCID: PMC8692516 DOI: 10.1007/s13280-021-01662-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 10/11/2021] [Accepted: 10/26/2021] [Indexed: 05/25/2023]
Abstract
The Arctic marine ecosystem is shaped by the seasonality of the solar cycle, spanning from 24-h light at the sea surface in summer to 24-h darkness in winter. The amount of light available for under-ice ecosystems is the result of different physical and biological processes that affect its path through atmosphere, snow, sea ice and water. In this article, we review the present state of knowledge of the abiotic (clouds, sea ice, snow, suspended matter) and biotic (sea ice algae and phytoplankton) controls on the underwater light field. We focus on how the available light affects the seasonal cycle of primary production (sympagic and pelagic) and discuss the sensitivity of ecosystems to changes in the light field based on model simulations. Lastly, we discuss predicted future changes in under-ice light as a consequence of climate change and their potential ecological implications, with the aim of providing a guide for future research.
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Affiliation(s)
- Giulia Castellani
- Alfred-Wegener-Institute Helmholtz-Zentrum für Polar und Meeresforschung, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | - Gaëlle Veyssière
- British Antarctic Survey, High Cross Madingley Road, Cambridge, CB3 0ET UK
| | - Michael Karcher
- Alfred-Wegener-Institute Helmholtz-Zentrum für Polar und Meeresforschung, Am Handelshafen 12, 27570 Bremerhaven, Germany
- Ocean Atmosphere Systems GmbH, Tewessteg 4, 20249 Hamburg, Germany
| | - Julienne Stroeve
- University College London, Gower St, London, WC1E 6BT UK
- University of Manitoba, 66 Chancellors Cir, Winnipeg, MB R3T 2N2 Canada
- National Snow and Ice Data Center CIRES, 449 UCB University of Colorado, Boulder, CO 80309-0449 USA
| | - S. Neil Banas
- University of Strathclyde, Livingstone Tower, 26 Richmond Street, Glasgow, G1 1XH UK
| | | | - S. Andrew Brierley
- Pelagic Ecology Research Group, Scottish Oceans Institute, Gatty Marine Laboratory, School of Biology, University of St Andrews, Fife, KY16 8LB Scotland, UK
| | - Stacey Connan
- University of Strathclyde, Livingstone Tower, 26 Richmond Street, Glasgow, G1 1XH UK
| | - Finlo Cottier
- Scottish Association for Marine Science, Oban, Argyll and Bute, PA37 1QA Scotland, UK
| | - Fabian Große
- University of Strathclyde, Livingstone Tower, 26 Richmond Street, Glasgow, G1 1XH UK
- German Federal Institute of Hydrology, Department for Microbilogy, Am Mainzer Tor 1, 56068 Koblenz, Germany
| | - Laura Hobbs
- University of Strathclyde, Livingstone Tower, 26 Richmond Street, Glasgow, G1 1XH UK
| | - Christian Katlein
- Alfred-Wegener-Institute Helmholtz-Zentrum für Polar und Meeresforschung, Am Handelshafen 12, 27570 Bremerhaven, Germany
| | | | - David McKee
- University of Strathclyde, Livingstone Tower, 26 Richmond Street, Glasgow, G1 1XH UK
| | - Andrew Orkney
- University of Oxford, South Parks Road, Oxford, OX1 3AN UK
| | - Roland Proud
- Pelagic Ecology Research Group, Scottish Oceans Institute, Gatty Marine Laboratory, School of Biology, University of St Andrews, Fife, KY16 8LB Scotland, UK
| | - Vibe Schourup-Kristensen
- Department of Applied Marine Ecology and Modeling, Aarhus University, Nordre Ringgade 1, 8000 Aarhus C, Denmark
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Trends in Satellite Earth Observation for Permafrost Related Analyses—A Review. REMOTE SENSING 2021. [DOI: 10.3390/rs13061217] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Climate change and associated Arctic amplification cause a degradation of permafrost which in turn has major implications for the environment. The potential turnover of frozen ground from a carbon sink to a carbon source, eroding coastlines, landslides, amplified surface deformation and endangerment of human infrastructure are some of the consequences connected with thawing permafrost. Satellite remote sensing is hereby a powerful tool to identify and monitor these features and processes on a spatially explicit, cheap, operational, long-term basis and up to circum-Arctic scale. By filtering after a selection of relevant keywords, a total of 325 articles from 30 international journals published during the last two decades were analyzed based on study location, spatio-temporal resolution of applied remote sensing data, platform, sensor combination and studied environmental focus for a comprehensive overview of past achievements, current efforts, together with future challenges and opportunities. The temporal development of publication frequency, utilized platforms/sensors and the addressed environmental topic is thereby highlighted. The total number of publications more than doubled since 2015. Distinct geographical study hot spots were revealed, while at the same time large portions of the continuous permafrost zone are still only sparsely covered by satellite remote sensing investigations. Moreover, studies related to Arctic greenhouse gas emissions in the context of permafrost degradation appear heavily underrepresented. New tools (e.g., Google Earth Engine (GEE)), methodologies (e.g., deep learning or data fusion etc.) and satellite data (e.g., the Methane Remote Sensing LiDAR Mission (Merlin) and the Sentinel-fleet) will thereby enable future studies to further investigate the distribution of permafrost, its thermal state and its implications on the environment such as thermokarst features and greenhouse gas emission rates on increasingly larger spatial and temporal scales.
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Terhaar J, Lauerwald R, Regnier P, Gruber N, Bopp L. Around one third of current Arctic Ocean primary production sustained by rivers and coastal erosion. Nat Commun 2021; 12:169. [PMID: 33420093 PMCID: PMC7794587 DOI: 10.1038/s41467-020-20470-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 12/03/2020] [Indexed: 01/29/2023] Open
Abstract
Net primary production (NPP) is the foundation of the oceans' ecosystems and the fisheries they support. In the Arctic Ocean, NPP is controlled by a complex interplay of light and nutrients supplied by upwelling as well as lateral inflows from adjacent oceans and land. But so far, the role of the input from land by rivers and coastal erosion has not been given much attention. Here, by upscaling observations from the six largest rivers and using measured coastal erosion rates, we construct a pan-Arctic, spatio-temporally resolved estimate of the land input of carbon and nutrients to the Arctic Ocean. Using an ocean-biogeochemical model, we estimate that this input fuels 28-51% of the current annual Arctic Ocean NPP. This strong enhancement of NPP is a consequence of efficient recycling of the land-derived nutrients on the vast Arctic shelves. Our results thus suggest that nutrient input from the land is a key process that will affect the future evolution of Arctic Ocean NPP.
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Affiliation(s)
- Jens Terhaar
- grid.460789.40000 0004 4910 6535Laboratoire des Sciences du Climat et de l’Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, 91191 Gif-sur-Yvette, France ,grid.4989.c0000 0001 2348 0746Biogeochemistry and Earth System Modelling, Department of Geoscience, Environment and Society, Université Libre de Bruxelles, Bruxelles, Belgium ,grid.5734.50000 0001 0726 5157Climate and Environmental Physics, Physics Institute, University of Bern, Bern, Switzerland ,grid.5734.50000 0001 0726 5157Oeschger Center for Climate Change Research, University of Bern, Bern, Switzerland
| | - Ronny Lauerwald
- grid.460789.40000 0004 4910 6535Laboratoire des Sciences du Climat et de l’Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, 91191 Gif-sur-Yvette, France ,grid.4989.c0000 0001 2348 0746Biogeochemistry and Earth System Modelling, Department of Geoscience, Environment and Society, Université Libre de Bruxelles, Bruxelles, Belgium ,Université Paris-Saclay, INRAE, AgroParisTech, UMR ECOSYS, 78850 Thiverval-Grignon, France
| | - Pierre Regnier
- grid.4989.c0000 0001 2348 0746Biogeochemistry and Earth System Modelling, Department of Geoscience, Environment and Society, Université Libre de Bruxelles, Bruxelles, Belgium
| | - Nicolas Gruber
- grid.5801.c0000 0001 2156 2780Environmental Physics, Institute of Biogeochemistry and Pollutant Dynamics, ETH Zurich, Zurich, Switzerland
| | - Laurent Bopp
- grid.462844.80000 0001 2308 1657LMD/IPSL, Ecole Normale Supérieure/PSL University, CNRS, Ecole Polytechnique, Sorbonne Université, Paris, France
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Jong D, Bröder L, Tanski G, Fritz M, Lantuit H, Tesi T, Haghipour N, Eglinton TI, Vonk JE. Nearshore Zone Dynamics Determine Pathway of Organic Carbon From Eroding Permafrost Coasts. GEOPHYSICAL RESEARCH LETTERS 2020; 47:e2020GL088561. [PMID: 32999517 PMCID: PMC7507779 DOI: 10.1029/2020gl088561] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 06/26/2020] [Accepted: 07/04/2020] [Indexed: 06/11/2023]
Abstract
Collapse of permafrost coasts delivers large quantities of particulate organic carbon (POC) to Arctic coastal areas. With rapidly changing environmental conditions, sediment and organic carbon (OC) mobilization and transport pathways are also changing. Here, we assess the sources and sinks of POC in the highly dynamic nearshore zone of Herschel Island-Qikiqtaruk (Yukon, Canada). Our results show that POC concentrations sharply decrease, from 15.9 to 0.3 mg L-1, within the first 100-300 m offshore. Simultaneously, radiocarbon ages of POC drop from 16,400 to 3,600 14C years, indicating rapid settling of old permafrost POC to underlying sediments. This suggests that permafrost OC is, apart from a very narrow resuspension zone (<5 m water depth), predominantly deposited in nearshore sediments. While long-term storage of permafrost OC in marine sediments potentially limits biodegradation and its subsequent release as greenhouse gas, resuspension of fine-grained, OC-rich sediments in the nearshore zone potentially enhances OC turnover.
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Affiliation(s)
- Dirk Jong
- Department of Earth SciencesVrije Universiteit AmsterdamAmsterdamThe Netherlands
| | - Lisa Bröder
- Department of Earth SciencesVrije Universiteit AmsterdamAmsterdamThe Netherlands
- Geological InstituteSwiss Federal Institute of Technology (ETH)ZürichSwitzerland
| | - George Tanski
- Department of Earth SciencesVrije Universiteit AmsterdamAmsterdamThe Netherlands
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine ResearchPotsdamGermany
| | - Michael Fritz
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine ResearchPotsdamGermany
| | - Hugues Lantuit
- Alfred Wegener Institute Helmholtz Centre for Polar and Marine ResearchPotsdamGermany
- Institute for GeosciencesUniversity of PotsdamPotsdamGermany
| | | | - Negar Haghipour
- Geological InstituteSwiss Federal Institute of Technology (ETH)ZürichSwitzerland
| | - Timothy I. Eglinton
- Geological InstituteSwiss Federal Institute of Technology (ETH)ZürichSwitzerland
| | - Jorien E. Vonk
- Department of Earth SciencesVrije Universiteit AmsterdamAmsterdamThe Netherlands
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7
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Abstract
Permafrost coastlines represent a large portion of the world’s coastal area and these areas have become increasingly vulnerable in the face of climate change. The predominant mechanism of coastal erosion in these areas has been identified through several observational studies as thermomechanical erosion—a joint removal of sediment through the melting of interstitial ice (thermal energy) and abrasion from incoming waves (mechanical energy). However, further developments are needed looking how common design parameters in coastal engineering (such as wave height, period, sediment size, etc.) contribute to the process. This paper presents the current state of the art with the objective of establishing the necessary research background to develop a process-based approach to predicting permafrost erosion. To that end, an overarching framework is presented that includes all major, erosion-relevant processes, while delineating means to accomplish permafrost modelling in experimental studies. Preliminary modelling of generations zero and one models, within this novel framework, was also performed to allow for early conclusions as to how well permafrost erosion can currently be modelled without more sophisticated setups.
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