Fresh water masses in the Kara Sea during summer

Johnson, Donald R.; McClimans, T. A.; King, S.E.; Grenness, Ø.

doi:10.1016/s0924-7963(96)00093-0

Cited by 29 publications

(20 citation statements)

References 11 publications

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“…Water may thus reach the shelf edge with widely different shelf signatures. In spring and summer there is much northward transport of river water to the central Kara Sea (Johnson et al, 1997;Harms and Karcher, 1999), and part of the river water will find its way to the shelf edge and the central Arctic through this route north of Severnaya Zemlya. But model studies of Harms and Karcher (1999) and Harms et al (2000) show that the annual transport is governed by the eastward circulation prevailing in autumn and winter.…”

Section: The Estuarine Behaviour Of 228 Ramentioning

confidence: 99%

228Ra and 226Ra in the Kara and Laptev seas

Loeff

Kühne

Wahsner

et al. 2003

Continental Shelf Research

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The surface water in the Transpolar Drift in the Arctic Ocean has a strong signature of 228 Ra. In an earlier study of 228 Ra in the open Arctic we showed that the major 228 Ra source had to be in the Siberian shelf seas, but only a single shelf station was published so far. Here we investigate the sources of this signal on the Siberian shelves by measurements of 228 Ra and 226 Ra in surface waters of the Kara and Laptev Sea, including the Ob, Yenisey and Lena estuaries.In the Ob and Lena rivers we found an indication for a very strong and unexpected removal of both isotopes in the early stage of estuarine mixing, presumably related to flocculation of organic-rich material. Whereas 226 Ra behaves conservatively on the shelf, the distribution of 228 Ra is governed by large inputs on the shelves, although sources are highly variable. In the Kara Sea the maximum activity was found in the Baydaratskaya Bay, where tidal resonance and low freshwater supply favour 228 Ra accumulation. The Laptev Sea is a stronger source for 228 Ra than the Kara Sea. Since a large part of Kara Sea water flows through the Laptev Sea, the 228 Ra signal in the Transpolar Drift can be described as originating on the Laptev shelf.The combined freshwater inputs from the Eurasian shelves thus produce a common radium signature with a 228 Ra/ 226 Ra activity ratio of 4.0 at 20% river water. The radium signals of the individual Siberian rivers and shelves cannot be separated, but their signal is significantly different from the signal produced on the Canadian shelf (Smith et al., in press). In this respect, the radium tracers add to the information given by Barium. Moreover, with the 5.8 year half-life of 228 Ra, they have the potential to serve as a tracer for the age of a water mass since its contact with the shelves. r

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Section: The Estuarine Behaviour Of 228 Ramentioning

confidence: 99%

228Ra and 226Ra in the Kara and Laptev seas

Loeff

Kühne

Wahsner

et al. 2003

Continental Shelf Research

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“…The central and the eastern parts of the Kara Sea are dominated by the Ob and Yenisei Delta ( = Yamal Plateau) with a characteristic depth of 25 -30 m. To the west, the Novaya Zemlya Trough reaches depths of more than 300 m and separates the Yamal Plateau from Novaya Zemlya. The Kara Sea is connected to the St. Anna Trough further North by a sill of about 200 m water depth (Johnson et al, 1997). The Yenisei River is Siberia's largest river and among the 10 largest rivers in the world (Gordeev, 2000;Milliman, 1991), with a drainage area of 2.58 Â 10 6 km 2 and a length of 3844 km (Milliman and Meade, 1983;Telang et al, 1991).…”

Section: Introductionmentioning

confidence: 99%

Recent particulate organic carbon and total suspended matter fluxes from the Ob and Yenisei Rivers into the Kara Sea (Siberia)

et al. 2004

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The Ob and Yenisei Rivers account for more than one-third of the total fresh water supply to the Arctic Ocean. In the past, their sediment load and particulate organic carbon (POC) discharge into the Kara Sea has been measured at stations in the hinterland far south of the estuaries. Suspended matter has been sampled in the estuaries and southern Kara Sea within the framework of the joint Russian -German ''SIRRO'' program (Siberian River Run-Off), allowing a reliable new estimate of fluxes from the rivers into the Kara Sea. Our estimates of annual supplies of sediment (3.76 Â 10 6 t), particulate organic carbon (0.27 Â 10 6 t) and particulate nitrogen (PN) (0.027 Â 10 6 t) from the Ob River to the Kara Sea are lower than earlier estimates from the northernmost gauging station in the hinterland due to deposition of particulate matter in the Ob Bay. On the other hand, our estimates of the Yenisei's annual sediment (5.03 Â 10 6 t), particulate organic carbon (0.57 Â 10 6 t) and particulate nitrogen (0.084 Â 10 6 t) supplies to the Kara Sea are probably too high, as they suggest a pure bypass system in the investigated area. We differentiate between an area of recent deposition in the south of the Kara Sea and an area of recent organic matter degradation further north. D

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“…This decoupling of the surface layer makes it susceptible to wind forcing in the shelf regions (e.g. Johnson et al 1997;Campeau et al 1999) and the low-salinity plume may extend far to the north during high runoff and strong offshore winds. Strong salinity gradients may result in hydrographic fronts with differences of more than 10±20 psu over short distances (Burenkov and Vasil'kov 1995;Burenkov et al 1997;Johnson et al 1997).…”

Section: Introductionmentioning

confidence: 99%

Freshwater chlorophycean algae in recent marine sediments of the Beaufort, Laptev and Kara Seas (Arctic Ocean) as indicators of river runoff

Matthießen

Kunz-Pirrung

Mudie

2000

International Journal of Earth Sciences

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Freshwater chlorophycean algae in recent marine sediments of the Beaufort, Laptev and Kara Seas (Arctic Ocean) as indicators of river runoff Abstract Freshwater chlorophycean algae are characteristic organic-walled microfossils in recent coastal and shelf sediments from the Beaufort, Laptev and Kara seas (Arctic Ocean). The persistent occurrence of the chlorophycean algae Pediastrum spp. and Botryococcus cf. braunii in marine palynomorph assemblages is related to the discharge of freshwater and suspended matter from the large Siberian and North American rivers into the Arctic shelf seas. The distribution patterns of these algae in the marine environments reflect the predominant deposition of riverine sediments and organic matter along the salinity gradient from the outer estuaries and prodeltas to the shelf break. Sedimentary processes overprint the primary distribution of these algae. Resuspension of sediments by waves and bottom currents may transport sediments in the bottom nepheloid layer along the submarine channels to the shelf break. Bottom sediments and microfossils may be incorporated into sea ice during freeze-up in autumn and winter leading to an export from the shelves into the deep sea. The presence of these freshwater algae in sea-ice and bottom sediments in the central Arctic Ocean confirm that transport in sea ice is an important process which leads to a redistribution of shallow water microfossils.Keywords Arctic Ocean´Beaufort Sea´Laptev SeaḰ ara Sea´Recent sediments´Chlorophyte distribution´Freshwater discharge J. Matthiessen ( ) )´M. Kunz-Pirrung

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Fresh water masses in the Kara Sea during summer

Cited by 29 publications

References 11 publications

228Ra and 226Ra in the Kara and Laptev seas

228Ra and 226Ra in the Kara and Laptev seas

Recent particulate organic carbon and total suspended matter fluxes from the Ob and Yenisei Rivers into the Kara Sea (Siberia)

Freshwater chlorophycean algae in recent marine sediments of the Beaufort, Laptev and Kara Seas (Arctic Ocean) as indicators of river runoff

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