Particle fluxes and geochemistry on the Canadian Beaufort Shelf: Implications for sediment transport and deposition

O'Brien, Mary; Macdonald, Robie W.; Melling, Humfrey; Iseki, Kazuo

doi:10.1016/j.csr.2005.09.007

Cited by 168 publications

(168 citation statements)

References 64 publications

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“…The flux of organic carbon on the Lomonosov Ridge is similar to the fluxes found in the seasonally ice-covered Greenland Sea (Noji et al, 2001;Peinert et al, 2001;Peinert and Noji, 2004) but up to nine times lower than fluxes determined in the southern Kara (Gaye et al, submitted) and Beaufort Seas (Moran, 2004;O'Brien et al, 2006). The latter fluxes are large because of the river discharge in these regions (Table 5).…”

Section: Annual Fluxessupporting

confidence: 49%

Lithogenic and biogenic particle fluxes on the Lomonosov Ridge (central Arctic Ocean) and their relevance for sediment accumulation: Vertical vs. lateral transport

Fahl

Nöthig

2007

Deep Sea Research Part I: Oceanographic Research Papers

108

107

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Investigations of lithogenic and biogenic particle fluxes using long-term sediment traps are still very rare in the northern high latitudes and are restricted to the arctic marginal seas and sub-arctic regions. Here data on the variability of fluxes of lithogenic matter, CaCO 3 , opal, and organic carbon and biomarker composition from the central Arctic Ocean are presented for a 1-year period. The study was carried out on material obtained from a long-term mooring system equipped with two multi-sampling traps, at 150 and 1550 m depth, and deployed on the southern Lomonosov Ridge close to the Laptev Sea continental margin from September 1995 to August 1996. In addition, data from surface sediments were included in the study. Annual fluxes of lithogenic matter, CaCO 3 , opal, and particulate organic carbon were 3.9, 0.8, 2.6, and 1.5 g m À2 y À1 , respectively, in the shallow trap and 11.3, 0.5, 2.9, and 1.05 g m À2 y À1 , respectively, in the deep trap.Both the shallow and the deep trap showed significant variations in vertical flux over the year. Higher values were found from mid-July to the end of October (total mass flux of 75-130 mg m À2 d À1 in the shallow trap and 40-225 mg m À2 d À1 in the deep trap). During all other months, fluxes were fairly low in both traps (most total mass flux values o10 mg m À2 d À1 ). The interval of increased fluxes can be separated into (1) a mid-July/August maximum caused by increased primary production as documented in high abundances of marine biomarkers and diatoms and (2) a September/October maximum caused by increased influence of Lena River discharge indicated by maximum lithogenic flux and large amounts of terrigenous/fluvial biomarkers in both traps. During September/October, total mass fluxes in the deep trap were significantly higher than in the shallow trap, suggesting a lateral sediment flux at greater depth. The lithogenic flux data also support the importance of sediment input from the Laptev Sea for the sediment accumulation on the Lomonosov Ridge on geological time scales, as indicated in sedimentary records from this region. r

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Section: Annual Fluxessupporting

confidence: 49%

Lithogenic and biogenic particle fluxes on the Lomonosov Ridge (central Arctic Ocean) and their relevance for sediment accumulation: Vertical vs. lateral transport

Fahl

Nöthig

2007

Deep Sea Research Part I: Oceanographic Research Papers

108

107

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“…West of Shallow Bay, sediment movement in the nearshore is also controlled by coastal currents (Pelletier, 1984). O'Brien et al (2006) note that the Mackenzie River is the largest source of sediment to the arctic region; therefore the discharge of the Mackenzie River is the major component for the geostatistical modeling of Beaufort Shelf sediments. The goals of this study are:…”

Section: Introductionmentioning

confidence: 99%

Geostatistical mapping and spatial variability of surficial sediment types on the Beaufort Shelf based on grain size data

Jerosch

2013

Journal of Marine Systems

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The paper describes an approach for a quality controlled mapping of grain sizes and sediment textures for the Beaufort Shelf in the Canadian Arctic. The approach is based on grain size data collected during the Nahidik Program (2005Program ( -2009 and earlier. A replenishment of grain size data since the 1980s, as well as the consideration of correlating parameters (bathymetry, slope and sediment input) to a cokriging algorithm, amends the former way of mapping the surficial sediments of the Beaufort Shelf. The cokriging analysis showed that the simulation of a sediment input by the Mackenzie River, modeled as a cost-distance function, was the key variable in reducing the errors of the output estimate. Furthermore, the approach compares the geostatistical interpolation methods of ordinary kriging and cokriging and recommends the use of a combination of both. The predicted mean standard errors showed that in this study cokriging was the superior interpolation method for clay, silt and sand while ordinary kriging was more suitable for gravel. A new sediment texture map, based on the grain size maps, is provided according to commonly used grain size and sediment type classification systems.

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“…They show large seasonal variations (Fig. 1), with a maximum during the summer period (from June to September) and lower values during the rest of the year (Macdonald et al, 1998;O'Brien et al, 2006). Over the last 11 years, this discharge typically varied between 4000 m 3 s −1 (winter) and 25 000 m 3 s −1 (summer).…”

Section: Multiyear Spm Concentrations and Fluxes At The Mackenzie Rivmentioning

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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Particle fluxes and geochemistry on the Canadian Beaufort Shelf: Implications for sediment transport and deposition

Cited by 168 publications

References 64 publications

Lithogenic and biogenic particle fluxes on the Lomonosov Ridge (central Arctic Ocean) and their relevance for sediment accumulation: Vertical vs. lateral transport

Lithogenic and biogenic particle fluxes on the Lomonosov Ridge (central Arctic Ocean) and their relevance for sediment accumulation: Vertical vs. lateral transport

Geostatistical mapping and spatial variability of surficial sediment types on the Beaufort Shelf based on grain size data

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

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