The Arctic Ocean Estuary

McClelland, J. W.; Holmes, Robert M.; Dunton, Kenneth H.; Macdonald, Robie W.

doi:10.1007/s12237-010-9357-3

Cited by 229 publications

(161 citation statements)

References 97 publications

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“…often dominates floodplains, increasing carbon and nitrogen availability simultaneously, as water moves downstream (Ruess et al, 2013;Taylor, 2013;Malone et al, 2018). Furthermore, headwater aquatic primary production (algae) is often phosphorus limited, resulting in rapid nitrification of what little ammonium makes it to the stream channel, though nitrogen demand increases as rivers meet the sea McClelland et al, 2012). There is evidence that rapid climate change at high latitudes and associated permafrost degradation are increasing nitrogen availability and potentially induce shifts in the nitrogen cycle (Jones et al, 2005;Abbott et al, 2015;Voigt et al, 2017).…”

Section: Riparian Corridors Function As Kidneys Of River Systemsmentioning

confidence: 99%

Riparian Corridors: A New Conceptual Framework for Assessing Nitrogen Buffering Across Biomes

Pinay

Bernal

Abbott

et al. 2018

Front. Environ. Sci.

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Anthropogenic activities have more than doubled the amount of reactive nitrogen circulating on Earth, creating excess nutrients across the terrestrial-aquatic gradient. These excess nutrients have caused worldwide eutrophication, fundamentally altering the functioning of freshwater and marine ecosystems. Riparian zones have been recognized to buffer diffuse nitrate pollution, reducing delivery to aquatic ecosystems, but nutrient removal is not their only function in river systems. In this paper, we propose a new conceptual framework to test the capacity of riparian corridors to retain, remove, and transfer nitrogen along the continuum from land to sea under different climatic conditions. Because longitudinal, lateral, and vertical connectivity in riparian corridors influences their functional role in landscapes, we highlight differences in these parameters across biomes. More specifically, we explore how the structure of riparian corridors shapes stream morphology (the river's spine), their multiple functions at the interface between the stream and its catchment (the skin), and their biogeochemical capacity to retain and remove nitrogen (the kidneys). We use the nitrogen cycle as an example because nitrogen pollution is one of the most pressing global environmental issues, influencing directly and indirectly virtually all ecosystems on Earth. As an initial test of the applicability of our interbiome approach, we present synthesis results of gross ammonification and net nitrification from diverse ecosystems.

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Section: Riparian Corridors Function As Kidneys Of River Systemsmentioning

confidence: 99%

Riparian Corridors: A New Conceptual Framework for Assessing Nitrogen Buffering Across Biomes

Pinay

Bernal

Abbott

et al. 2018

Front. Environ. Sci.

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“…First, the satellite observations used in the present study cover only 4 months of the year, i.e. June to September, a period during which about 50 % of the freshwater discharge occurs (McClelland et al, 2012). Assuming a constant SPM concentration in the river throughout the year, extrapolating our results to the winter period would lead to a total of 40 (±5) × 10 12 g yr −1 for SPM, i.e., still different by a factor of 3 from the delivery estimated by Macdonald et al (1998).…”

Section: Doxaran Et Al: a 50 % Increase In The Mass Of Terrestriamentioning

confidence: 99%

A 50 % increase in the mass of terrestrial particles delivered by the Mackenzie River into the Beaufort Sea (Canadian Arctic Ocean) over the last 10 years

Doxaran

Devred²,

Babin³

2015

Biogeosciences

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Abstract. Global warming has a significant impact on the regional scale on the Arctic Ocean and surrounding coastal zones (i.e., Alaska, Canada, Greenland, Norway and Russia). The recent increase in air temperature has resulted in increased precipitation along the drainage basins of Arctic rivers. It has also directly impacted land and seawater temperatures with the consequence of melting permafrost and sea ice. An increase in freshwater discharge by main Arctic rivers has been clearly identified in time series of field observations. The freshwater discharge of the Mackenzie River has increased by 25 % since 2003. This may have increased the mobilization and transport of various dissolved and particulate substances, including organic carbon, as well as their export to the ocean. The release from land to the ocean of such organic material, which has been sequestered in a frozen state since the Last Glacial Maximum, may significantly impact the Arctic Ocean carbon cycle as well as marine ecosystems.In this study we use 11 years of ocean color satellite data and field observations collected in 2009 to estimate the mass of terrestrial suspended solids and particulate organic carbon delivered by the Mackenzie River into the Beaufort Sea (Arctic Ocean). Our results show that during the summer period, the concentration of suspended solids at the river mouth, in the delta zone and in the river plume has increased by 46, 71 and 33 %, respectively, since 2003. Combined with the variations observed in the freshwater discharge, this corresponds to a more than 50 % increase in the particulate (terrestrial suspended particles and organic carbon) export from the Mackenzie River into the Beaufort Sea.

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“…During the rest of the year river outflow is greatly reduced by the presence of land-fast ice at the river mouths (McClelland et al, 2012). Monitoring Arctic coastal environments is difficult and costly as they constitute remote sparsely populated areas affected by extreme meteorological conditions.…”

Section: Doxaran Et Al: Optical Characterisation Of Suspended Parmentioning

confidence: 99%

Optical characterisation of suspended particles in the Mackenzie River plume (Canadian Arctic Ocean) and implications for ocean colour remote sensing

et al. 2012

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Abstract. Climate change significantly impacts Arctic shelf regions in terms of air temperature, ultraviolet radiation, melting of sea ice, precipitation, thawing of permafrost and coastal erosion. Direct consequences have been observed on the increasing Arctic river flow and a large amount of organic carbon sequestered in soils at high latitudes since the last glacial maximum can be expected to be delivered to the Arctic Ocean during the coming decade. Monitoring the fluxes and fate of this terrigenous organic carbon is problematic in such sparsely populated regions unless remote sensing techniques can be developed and proved to be operational.The main objective of this study is to develop an ocean colour algorithm to operationally monitor dynamics of suspended particulate matter (SPM) on the Mackenzie River continental shelf (Canadian Arctic Ocean) using satellite imagery. The water optical properties are documented across the study area and related to concentrations of SPM and particulate organic carbon (POC). Robust SPM and POC : SPM proxies are identified, such as the light backscattering and attenuation coefficients, and relationships are established between these optical and biogeochemical parameters. Following a semi-analytical approach, a regional SPM quantification relationship is obtained for the inversion of the water reflectance signal into SPM concentration. This relationship is reproduced based on independent field optical measurements. It is successfully applied to a selection of MODIS satellite data which allow estimating fluxes at the river mouth and monitoring the extension and dynamics of the Mackenzie River surface plume in 2009, 2010 and 2011. Good agreement is obtained with field observations representative of the whole water column in the river delta zone where terrigenous SPM is mainly constrained (out of short periods of maximum river outflow). Most of the seaward export of SPM is observed to occur within the west side of the river mouth.Future work will require the validation of the developed SPM regional algorithm based on match-ups with field measurements, then the routine application to ocean colour satellite data in order to better estimate the fluxes and fate of SPM and POC delivered by the Mackenzie River to the Arctic Ocean.

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The Arctic Ocean Estuary

Cited by 229 publications

References 97 publications

Riparian Corridors: A New Conceptual Framework for Assessing Nitrogen Buffering Across Biomes

Riparian Corridors: A New Conceptual Framework for Assessing Nitrogen Buffering Across Biomes

A 50 % increase in the mass of terrestrial particles delivered by the Mackenzie River into the Beaufort Sea (Canadian Arctic Ocean) over the last 10 years

Optical characterisation of suspended particles in the Mackenzie River plume (Canadian Arctic Ocean) and implications for ocean colour remote sensing

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