Carbon and nitrogen cycling within the Bering/Chukchi Seas: Source regions for organic matter effecting AOU demands of the Arctic Ocean

Walsh, John J.; McRoy, C. Peter; Coachman, L. K.; Goering, John J.; Nihoul, Jacques; Whitledge, Terry E.; Blackburn, T. H.; Parker, Patrick L.; Wirick, Creighton D.; Shuert, P.G.; Grebmeier, Jacqueline M.; Springer, Alan M.; Tripp, R. D.; Hansell, Dennis A.; Djenidi, Salim; Deleersnijder, Éric; Henriksen, Kaj; Lund, Bente; Andersen, Per; Muller‐Karger, Frank E.; Dean, Kenneth

doi:10.1016/0079-6611(89)90006-2

Cited by 372 publications

(173 citation statements)

References 81 publications

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“…Woodgate et al, 2005) reaching into the Makarov Basin. These waters are enhanced in nutrients and reduced in oxygen by bacterial consumption of the summer bloom (Cooper et al, 1999;Walsh et al, 1989). While nutrients are released into the water column over the Chukchi shelf oxygen consumption is largest close to the bottom.…”

Section: Intrusions Of Chukchi Sea Water In the Upper Haloclinementioning

confidence: 99%

Utility of dissolved barium in distinguishing North American from Eurasian runoff in the Arctic Ocean

et al. 2012

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Dissolved barium has been shown to have the potential to distinguish Eurasian from North American (NA) river runoff. As part of the ARK-XXII/2 Polarstern expedition in summer 2007, Ba was analyzed in the Barents, Kara, Laptev seas, and the Eurasian Basins as well as the Makarov Basin up to the Alpha and Mendeleyev Ridges. By combining salinity, δ 18 O and initial phosphate corrected for mineralization with oxygen (PO 4 *) or N/P ratios we identified the water mass fractions of meteoric water, sea ice meltwater, and marine waters of Atlantic as well as Pacific origin in the upper water column. In all basins inside the lower halocline layer and the Arctic intermediate waters we find Ba concentrations close to those of the Fram Strait branch of the lower halocline (41-45 nM), reflecting the composition of the incoming Atlantic water. A layer of upper halocline water (UHW) with higher Ba concentrations (45-55 nM) is identified in the Makarov Basin. Atop of the UHW, the Surface Mixed Layer (SML), including the summer and winter mixed layers, has high concentrations of Ba (58-67 nM). In the SML of the investigated area of the central Arctic the meteoric fraction can be identified by assuming a conservative behavior of Ba to be primarily of Eurasian river origin. However, in productive coastal regions biological removal compromises the use of Ba to distinguish between Eurasian and NA rivers. As a consequence, the NA river water fraction is underestimated in productive surface waters or waters that have passed a productive region, whereas this fraction is overestimated in subsurface waters containing remineralised Ba, particularly when these waters have passed productive shelf regions. Especially in the Laptev Sea and small regions in the Barents Sea, Ba concentrations are low in surface waters. In the Laptev Sea exceptionally high Ba concentrations in shelf bottom waters indicate that Ba is removed from surface waters to deep waters by biological activity enhanced by increasing ice-free conditions as well as by scavenging by organic matter of terrestrial origin. We interpret high Ba concentrations in the UHW of the Makarov Basin to result from enrichment by remineralisation in bottom waters on the shelf of the Chukchi Sea and therefore the calculated NA runoff is an artefact. We conclude that no NA runoff can be demonstrated unequivocally anywhere during our expedition with the set of tracers considered here. Small contributions of NA runoff may have been masked by Ba depletion and could only be resolved by supportive tracers on the uptake history. We thus suggest that Ba has to be used with care as it can put limits but not yield quantitative water mass distributions. Only if the extra Ba inputs exceed the cumulative biological uptake the signal can be unequivocally attributed to NA runoff.

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Section: Intrusions Of Chukchi Sea Water In the Upper Haloclinementioning

confidence: 99%

Utility of dissolved barium in distinguishing North American from Eurasian runoff in the Arctic Ocean

et al. 2012

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“…Thus the total shelf export production to the Arctic Ocean equals around 0.07 Gton C yr Ϫ1 , corresponding to a mean of 15 g C m Ϫ2 yr Ϫ1 when the area of all the Arctic shelves (4.5 10 12 m 2 ) is considered. Although the total shelf export is small on a global scale the polar regions are one of the areas thought to be most affected by climatic changes because the sequestering of carbon dioxide potentially is significantly altered (Walsh et al 1989;Codispoti et al 1991).…”

Section: Resultsmentioning

confidence: 99%

Carbon utilization in the Eurasian sector of the Arctic Ocean

Olsson

Anderson

Frank

et al. 1999

Limnology & Oceanography

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Production and remineralization of carbon in the Eurasian sector have been estimated based on a combined data set of the expeditions. This sector includes the deep Nansen and Amundsen Basins and their linked shelf seas, i.e., the Barents, Kara, and Laptev Seas. The water masses in this region are composed of Atlantic water, river runoff, and sea ice-melt water. The fractionation between these source waters is elucidated from the ␦ 18 O-salinity relation and conservation of mass. By combining preformed nitrate concentrations of the source waters with the fractionation model and the measured nitrate concentrations, nitrate deficits and excesses are calculated. These concentrations are then converted to carbon equivalents by applying a C/N ratio, whereby a measure of apparent carbon utilization (ACU) is obtained. From the relative inventory of ACU along the slope and deep basin sections, we conclude that the shelf areas are the dominant productivity sites and that the productivity signal is transported to all water masses in the Eurasian Basin. The flux of utilized carbon from the Barents-Kara and Laptev Seas is about 0.022 Gton C yr Ϫ1 .The Arctic Ocean was once regarded as the most oligotrophic of oceans (e.g., Platt and Subba Rao 1975) due to extensive ice cover, low solar angle, and temperatures but is now considered as a potentially important site of carbon dioxide fixation (Wheeler et al. 1996). The marginal ice zones (MIZ) in particular, including polynyas, offer conditions that enhance photosynthetic activity (e.g., Alexander and Niebauer 1981;Rey and Loeng 1985;Sakshaug and Skjoldal 1989), especially if there is advection of nutrient-rich water into the MIZ area .The magnitude and extent of ice algal production is under current debate. A general consensus of the perennial ice cover inhibiting primary production prevails (e.g., SubbaAcknowledgments 1 Present address: Akvaplan-niva AS, Tromsø, Norway. The oceanographic groups and crew on board IB Oden and RV Polarstern are gratefully acknowledged for their assistance during the Oden-91 and ARK IX-4 expeditions. We are thankful to G.

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“…Earlier estimates indicated the pressure head was $0.7 m, but from 2001 to 2011, it increased by approximately 30% (Woodgate et al, 2012). The Pacific inflow is a source of heat, freshwater, and nutrients to the Arctic Ocean (Walsh et al, 1989;Woodgate et al, 2005a).…”

Section: Physical Conditions and Circulation In The Arcticmentioning

confidence: 99%

Advection in polar and sub-polar environments: Impacts on high latitude marine ecosystems

Hunt

Drinkwater

Arrigo

et al. 2016

Progress in Oceanography

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a b s t r a c tWe compare and contrast the ecological impacts of atmospheric and oceanic circulation patterns on polar and sub-polar marine ecosystems. Circulation patterns differ strikingly between the north and south. Meridional circulation in the north provides connections between the sub-Arctic and Arctic despite the presence of encircling continental landmasses, whereas annular circulation patterns in the south tend to isolate Antarctic surface waters from those in the north. These differences influence fundamental aspects of the polar ecosystems from the amount, thickness and duration of sea ice, to the types of organisms, and the ecology of zooplankton, fish, seabirds and marine mammals. Meridional flows in both the North Pacific and the North Atlantic oceans transport heat, nutrients, and plankton northward into the Chukchi Sea, the Barents Sea, and the seas off the west coast of Greenland. In the North Atlantic, the advected heat warms the waters of the southern Barents Sea and, with advected nutrients and plankton, supports immense biomasses of fish, seabirds and marine mammals. On the Pacific side of the Arctic, cold waters flowing northward across the northern Bering and Chukchi seas during winter and spring limit the ability of boreal fish species to take advantage of high seasonal production there. Southward flow of cold Arctic waters into sub-Arctic regions of the North Atlantic occurs mainly through Fram Strait with less through the Barents Sea and the Canadian Archipelago. In the Pacific, the transport of Arctic waters and plankton southward through Bering Strait is minimal.In the Southern Ocean, the Antarctic Circumpolar Current and its associated fronts are barriers to the southward dispersal of plankton and pelagic fishes from sub-Antarctic waters, with the consequent evolution of Antarctic zooplankton and fish species largely occurring in isolation from those to the north. The Antarctic Circumpolar Current also disperses biota throughout the Southern Ocean, and as a result, the biota tends to be similar within a given broad latitudinal band. South of the Southern Boundary of the ACC, there is a large-scale divergence that brings nutrient-rich water to the surface. This divergence, along with more localized upwelling regions and deep vertical convection in winter, generates elevated nutrient levels throughout the Antarctic at the end of austral winter. However, such elevated nutrient levels do not support elevated phytoplankton productivity through the entire Southern Ocean, as iron concentrations are rapidly removed to limiting levels by spring blooms in deep waters. However, coastal http://dx

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Carbon and nitrogen cycling within the Bering/Chukchi Seas: Source regions for organic matter effecting AOU demands of the Arctic Ocean

Cited by 372 publications

References 81 publications

Utility of dissolved barium in distinguishing North American from Eurasian runoff in the Arctic Ocean

Utility of dissolved barium in distinguishing North American from Eurasian runoff in the Arctic Ocean

Carbon utilization in the Eurasian sector of the Arctic Ocean

Advection in polar and sub-polar environments: Impacts on high latitude marine ecosystems

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