The influence of river discharge on the thawing of sea ice, Mackenzie River Delta: albedo and temperature analyses

Dean, Kenneth; Stringer, W. J.; Ahlnäs, Kristina; Searcy, Cheryl; Weingartner, Thomas J.

doi:10.1111/j.1751-8369.1994.tb00439.x

Cited by 49 publications

(29 citation statements)

References 9 publications

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“…Increased river discharge can accelerate ice melt when river water temperatures are higher than the coastal waters they flow into, and river water that flows out over the ice surface accelerates melting through effects on albedo (Dean et al 1994). However, most of the river water delivered during the spring freshet pushes out under the ice, mixing with and/or displacing the river water that built up slowly during the winter (Macdonald 2000).…”

Section: Nutrient and Organic Matter Dynamics In Arctic Estuariesmentioning

confidence: 98%

The Arctic Ocean Estuary

McClelland¹,

Holmes

Dunton³

et al. 2011

Estuaries and Coasts

228

150

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Large freshwater contributions to the Arctic Ocean from a variety of sources combine in what is, by global standards, a remarkably small ocean basin. Indeed, the Arctic Ocean receives ∼11% of global river discharge while accounting for only ∼1% of global ocean volume. As a consequence, estuarine gradients are a defining feature not only near-shore, but throughout the Arctic Ocean. Seaice dynamics also play a pivotal role in the salinity regime, adding salt to the underlying water during ice formation and releasing fresh water during ice thaw. Our understanding of physical-chemical-biological interactions within this complex system is rapidly advancing. However, much of the estuarine research to date has focused on summer, open water conditions. Furthermore, our current conceptual model for Arctic estuaries is primarily based on studies of a few major river inflows. Future advancement of estuarine research in the Arctic requires concerted seasonal coverage as well as a commitment to working within a broader range of systems. With clear signals of climate change occurring in the Arctic and greater changes anticipated in the future, there is good reason to accelerate estuarine research efforts in the region. In particular, elucidating estuarine dynamics across the near-shore to ocean-wide domains is vital for understanding potential climate impacts on local ecosystems as well as broader climate feedbacks associated with storage and release of fresh water and carbon.

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Section: Nutrient and Organic Matter Dynamics In Arctic Estuariesmentioning

confidence: 98%

The Arctic Ocean Estuary

McClelland¹,

Holmes

Dunton³

et al. 2011

Estuaries and Coasts

228

150

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“…Divergence and convergence forced by the wind produces an intermittent flaw lead beyond the approximately 20-m isobath and extensive rubble zones (stamukhi) at the outer edge of the landfast ice (Stirling and Cleator 1981;Macdonald and Carmack 1991). Spring breakup commences in early June, first clearing the inshore region of the delta (Dean et al 1994). Usually, by late September, the permanent pack-ice margin is located well offshore, the shelf is clear of ice, and, in an extreme year, there might be as much as 200±300 km of fetch; however, the ice-cover exhibits considerable year-to-year variability with attendant consequences on the oceanography of the shelf (e.g., Macdonald et al 1987).…”

Section: Canadian Beaufort Seamentioning

confidence: 98%

Coastal erosion vs riverine sediment discharge in the Arctic Shelf seas

Rachold

Grigoriev

Are³

et al. 2000

International Journal of Earth Sciences

186

139

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This article presents a comparison of sediment input by rivers and by coastal erosion into both the Laptev Sea and the Canadian Beaufort Sea (CBS). New data on coastal erosion in the Laptev Sea, which are based on field measurements and remote sensing information, and existing data on coastal erosion in the CBS as well as riverine sediment discharge into both the Laptev Sea and the CBS are included. Strong regional differences in the percentages of coastal erosion and riverine sediment supply are observed. The CBS is dominated by the riverine sediment discharge (64.4510 6 t a ±1 ) mainly of the Mackenzie River, which is the largest single source of sediments in the Arctic. Riverine sediment discharge into the Laptev Sea amounts to 24.1010 6 t a ±1 , more than 70% of which are related to the Lena River. In comparison with the CBS, the Laptev Sea coast on average delivers approximately twice as much sediment mass per kilometer, a result of higher erosion rates due to higher cliffs and seasonal ice melting. In the Laptev Sea sediment input by coastal erosion (58.410 6 t a ±1 ) is therefore more important than in the CBS and the ratio between riverine and coastal sediment input amounts to 0.4. Coastal erosion supplying 5.610 6 t a ±1 is less significant for the sediment budget of the CBS where riverine sediment discharge exceeds coastal sediment input by a factor of ca. 10.

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“…The transport, deposition, and reworking of sediments is strongly tied to ice, which both rafts the sediment and gouges the bottom. The deltaic processes in the arctic are unique: peak inflow precedes the breakup of coastal ice with the result that sediment-laden river water overflows the sea ice during spring (Dean et al 1994). Furthermore, there is an absence of the deltafront platform (Naidu and Mowatt 1975).…”

Section: Study Areamentioning

confidence: 98%

Organic carbon isotope ratios (δ 13 C) of Arctic Amerasian Continental shelf sediments

Naidu

Cooper

Finney

et al. 2000

International Journal of Earth Sciences

189

104

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Organic matter origins are inferred from carbon isotope ratios (d 13 C) in recent continental shelf sediments and major rivers from 465 locations from the north Bering-Chukchi-East Siberian-Beaufort Sea, Arctic Amerasia. Generally, there is a cross-shelf increase in d 13 C, which is due to progressive increased contribution seaward of marine-derived organic carbon to surface sediments. This conclusion is supported by the correlations between sediment d 13 C, OC/N, and d 15 N. The sources of total organic carbon (TOC) to the Amerasian margin sediments are primarily from marine water-column phytoplankton and terrigenous C 3 plants constituted of tundra taiga and angiosperms. In contrast to more temperate regions, the source of TOC from terrigenous C 4 and CAM plants to the study area is probably insignificant because these plants do not exist in the northern high latitudes. The input of carbon to the northern Alaskan shelf sediments from nearshore kelp community (Laminaria solidungula) is generally insignificant as indicated by the absence of high sediment d 13 C values (±16.5 to ±13.6½) which are typical of the macrophytes. Our study suggests that the isotopic composition of sediment TOC has potential application in reconstructing temporal changes in delivery and accumulation of organic matter resulting from glacial±interglacial changes in sea level and environments. Furthermore, recycling and advection of the extensive deposits of terrestrially derived organic matter from land, or the wide Amerasian margin, could be a mechanism for elevating total CO 2 and pCO 2 in the Arctic Basin halocline.

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The influence of river discharge on the thawing of sea ice, Mackenzie River Delta: albedo and temperature analyses

Cited by 49 publications

References 9 publications

The Arctic Ocean Estuary

The Arctic Ocean Estuary

Coastal erosion vs riverine sediment discharge in the Arctic Shelf seas

Organic carbon isotope ratios (δ 13 C) of Arctic Amerasian Continental shelf sediments

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