Composition and distribution of dissolved carbohydrates in the Beaufort Sea Mackenzie margin (Arctic Ocean)

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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The Seasonal Variability of the Arctic Ocean Ekman Transport and Its Role in the Mixed Layer Heat and Salt Fluxes

Journal of Climate ◽

10.1175/jcli3892.1 ◽

2006 ◽

Vol 19 (20) ◽

pp. 5366-5387 ◽

Cited By ~ 61

Author(s):

Jiayan Yang

Keyword(s):

Arctic Ocean ◽

Mixed Layer ◽

Seasonal Variability ◽

Surface Wind ◽

Beaufort Sea ◽

Ekman Transport ◽

The Arctic ◽

Ekman Pumping ◽

Basin Scale ◽

The Arctic Ocean

Abstract The oceanic Ekman transport and pumping are among the most important parameters in studying the ocean general circulation and its variability. Upwelling due to the Ekman transport divergence has been identified as a leading mechanism for the seasonal to interannual variability of the upper-ocean heat content in many parts of the World Ocean, especially along coasts and the equator. Meanwhile, the Ekman pumping is the primary mechanism that drives basin-scale circulations in subtropical and subpolar oceans. In those ice-free oceans, the Ekman transport and pumping rate are calculated using the surface wind stress. In the ice-covered Arctic Ocean, the surface momentum flux comes from both air–water and ice–water stresses. The data required to compute these stresses are now available from satellite and buoy observations. But no basin-scale calculation of the Ekman transport in the Arctic Ocean has been done to date. In this study, a suite of satellite and buoy observations of ice motion, ice concentration, surface wind, etc., will be used to calculate the daily Ekman transport over the whole Arctic Ocean from 1978 to 2003 on a 25-km resolution. The seasonal variability and its relationship to the surface forcing fields will be examined. Meanwhile, the contribution of the Ekman transport to the seasonal fluxes of heat and salt to the Arctic Ocean mixed layer will be discussed. It was found that the greatest seasonal variations of Ekman transports of heat and salt occur in the southern Beaufort Sea in the fall and early winter when a strong anticyclonic wind and ice motion are present. The Ekman pumping velocity in the interior Beaufort Sea reaches as high as 10 cm day−1 in November while coastal upwelling is even stronger. The contributions of the Ekman transport to the heat and salt flux in the mixed layer are also considerable in the region.

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Texture, Clay Mineralogy, and Chemistry of Bottom Sediments, West Beaufort Sea, Arctic Ocean

Contributions to the Geology of the Bering Sea Basin and Adjacent Regions - Geological Society of America Special Papers ◽

10.1130/spe151-p49 ◽

1975 ◽

pp. 49-58

Author(s):

A. S. NAIDU ◽

D. C. BURRELL ◽

D. W. HOOD ◽

J. A. DYGAS

Keyword(s):

Arctic Ocean ◽

Bottom Sediments ◽

Clay Mineralogy ◽

Beaufort Sea

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Effects of Vertical Water Mass Segregation on Bacterial Community Structure in the Beaufort Sea

Microorganisms ◽

10.3390/microorganisms7100385 ◽

2019 ◽

Vol 7 (10) ◽

pp. 385

Author(s):

Yunyun Fu ◽

Richard B. Rivkin ◽

Andrew S. Lang

Keyword(s):

Bacterial Community ◽

Sea Ice ◽

Arctic Ocean ◽

Community Composition ◽

Bacterial Communities ◽

Water Mass ◽

Beaufort Sea ◽

The Arctic ◽

The Arctic Ocean ◽

Mass Segregation

The Arctic Ocean is one of the least well-studied marine microbial ecosystems. Its low-temperature and low-salinity conditions are expected to result in distinct bacterial communities, in comparison to lower latitude oceans. However, this is an ocean currently in flux, with climate change exerting pronounced effects on sea-ice coverage and freshwater inputs. How such changes will affect this ecosystem are poorly constrained. In this study, we characterized the bacterial community compositions at different depths in both coastal, freshwater-influenced, and pelagic, sea-ice-covered locations in the Beaufort Sea in the western Canadian Arctic Ocean. The environmental factors controlling the bacterial community composition and diversity were investigated. Alphaproteobacteria dominated the bacterial communities in samples from all depths and stations. The Pelagibacterales and Rhodobacterales groups were the predominant taxonomic representatives within the Alphaproteobacteria. Bacterial communities in coastal and offshore samples differed significantly, and vertical water mass segregation was the controlling factor of community composition among the offshore samples, regardless of the taxonomic level considered. These data provide an important baseline view of the bacterial community in this ocean system that will be of value for future studies investigating possible changes in the Arctic Ocean in response to global change and/or anthropogenic disturbance.

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Early to mid-Holocene Atlantic water influx and deglacial meltwater events, Beaufort Sea Slope, Arctic Ocean

Quaternary Research ◽

10.1016/j.yqres.2003.08.003 ◽

2004 ◽

Vol 61 (1) ◽

pp. 14-21 ◽

Cited By ~ 48

Author(s):

John T. Andrews ◽

Gita Dunhill

Keyword(s):

Arctic Ocean ◽

Planktonic Foraminifera ◽

Sediment Accumulation ◽

Beaufort Sea ◽

Atlantic Water ◽

The Arctic ◽

Silty Clay ◽

Cold Event ◽

Radiocarbon Dates ◽

Average Grain Size

Holocene high-resolution cores from the margin of the Arctic Ocean are rare. Core P189AR-P45 collected in 405-m water depth on the Beaufort Sea slope, west of the Mackenzie River delta (70°33.03′N and 141°52.08′W), is in close vertical proximity to the present-day upper limit of modified Atlantic water. The 5.11-m core spans the interval between ∼6800 and 10,400 14C yr B.P. (with an 800-yr ocean reservoir correction). The sediment is primarily silty clay with an average grain-size of 9 φ. The chronology is constrained by seven radiocarbon dates. The rate of sediment accumulation averaged 1.35 mm/yr. Stable isotopic data (δ18O and δ13C) were obtained on the polar planktonic foraminifera Neogloboquadrina pachyderma (s) and the benthic infaunal species Cassidulina neoteretis. A distinct low-δ18O event is captured in both the benthic and planktonic data at ∼10,000 14C yr B.P.—probably recording the glacial Lake Agassiz outburst flood associated with the North Atlantic preboreal cold event. The benthic foraminifera are dominated in the earliest Holocene by C. neoteretis, a species associated with modified Atlantic water masses. This species decreases toward the core top with a marked environmental reversal occurring ∼7800 14C yr B.P. possibly coincident with the northern hemisphere 8200 cal yr B.P. cold event.

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