Primary productivity and export fluxes on the Canadian shelf of the Beaufort Sea: A modelling study

Lavoie, Diane; Macdonald, Robie W.; Denman, Kenneth L.

doi:10.1016/j.jmarsys.2008.07.007

Cited by 65 publications

(81 citation statements)

References 65 publications

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“…1D models have been coupled to water column models [Lavoie et al, 2009;Tedesco et al, 2012], showing that sea ice can substantially increase annual primary production, and contribute to the triggering of phytoplankton blooms, via the drastic increase in irradiance associated with ice retreat, water column stratification, or seeding of phytoplankton blooms. In the latter case, the potential role of ice algae depends on their viability, as well as on their degree of aggregation in the water column, controlling organic matter export to depth [Tedesco et al, 2012].…”

Section: Modelling and Up-scaling The Role Of Sea Ice In The Marine Bmentioning

confidence: 99%

Role of sea ice in global biogeochemical cycles: emerging views and challenges

Vancoppenolle

Meiners

Michel

et al. 2013

Quaternary Science Reviews

215

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International audienceObservations from the last decade suggest an important role of sea ice in the global biogeochemical cycles, promoted by (i) active biological and chemical processes within the sea ice; (ii) fluid and gas exchanges at the sea ice interface through an often permeable sea ice cover; and (iii) tight physical, biological and chemical interactions between the sea ice, the ocean and the atmosphere. Photosynthetic micro-organisms in sea ice thrive in liquid brine inclusions encased in a pure ice matrix, where they find suitable light and nutrient levels. They extend the production season, provide a winter and early spring food source, and contribute to organic carbon export to depth. Under-ice and ice edge phytoplankton blooms occur when ice retreats, favoured by increasing light, stratification, and by the release of material into the water column. In particular, the release of iron - highly concentrated in sea ice - could have large effects in the iron-limited Southern Ocean. The export of inorganic carbon transport by brine sinking below the mixed layer, calcium carbonate precipitation in sea ice, as well as active ice-atmosphere carbon dioxide (CO₂) fluxes, could play a central role in the marine carbon cycle. Sea ice processes could also significantly contribute to the sulphur cycle through the large production by ice algae of dimethylsulfoniopropionate (DMSP), the precursor of sulphate aerosols, which as cloud condensation nuclei have a potential cooling effect on the planet. Finally, the sea ice zone supports significant ocean-atmosphere methane (CH₄) fluxes, while saline ice surfaces activate springtime atmospheric bromine chemistry, setting ground for tropospheric ozone depletion events observed near both poles. All these mechanisms are generally known, but neither precisely understood nor quantified at large scales. As polar regions are rapidly changing, understanding the large-scale polar marine biogeochemical processes and their future evolution is of high priority. Earth system models should in this context prove essential, but they currently represent sea ice as biologically and chemically inert. Palaeoclimatic proxies are also relevant, in particular the sea ice proxies, inferring past sea ice conditions from glacial and marine sediment core records and providing analogues for future changes. Being highly constrained by marine biogeochemistry, sea ice proxies would not only contribute to but also benefit from a better understanding of polar marine biogeochemical cycles

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Section: Modelling and Up-scaling The Role Of Sea Ice In The Marine Bmentioning

confidence: 99%

Role of sea ice in global biogeochemical cycles: emerging views and challenges

Vancoppenolle

Meiners

Michel

et al. 2013

Quaternary Science Reviews

215

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“…Relatively high concentrations of DOC were observed in regions of the Beaufort shelf and reflected the influence of the Mackenzie River. Riverine input of nutrients supported patches of elevated primary production (Raimbault et al, unpublished data) and elevated concentrations and yields of TDAA in shelf waters, but generally low nutrient concentrations together with stratification of shelf waters during the summer typically resulted in the formation of a chlorophyll and productivity maximum at ∼ 30 m (Carmack et al, 2004;Lavoie et al, 2009;Raimbault et al, unpublished data). This pattern is reflected in elevated concentrations and yields of TDAA in subsurface waters.…”

Section: Concentrations and Bioavailability Of Dom In The Beaufort Seamentioning

confidence: 99%

“…Areas associated with seasonal upwelling, such as Barrow Canyon, are typically more productive (e.g., 8 g C m −2 d −1 ) than adjacent waters (Hill and Cota, 2005). In contrast, primary productivity in the Beaufort Sea is relatively low (10-70 g C m −2 yr −1 ) due to lower nutrient availability and reflects the strong influence from the Mackenzie River (Carmack et al, 2004;Sakshaug, 2004;Lavoie et al, 2009). Shelf waters are less productive within the river plume (e.g., < 10 g C m −2 yr −1 ) as a result of limited light penetration and become more productive outside the plume (30-70 g C m −1 yr −1 ; Sakshaug, 2004;Carmack and Wassmann, 2006).…”

Section: Introductionmentioning

confidence: 99%

Dissolved organic matter composition and bioavailability reflect ecosystem productivity in the Western Arctic Ocean

2012

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Abstract. Dissolved organic carbon (DOC) and total dissolved amino acids (TDAA) were measured in high (Chukchi Sea) and low (Beaufort Sea) productivity regions of the western Arctic Ocean to investigate the composition and bioavailability of dissolved organic matter (DOM). Concentrations and DOC-normalized yields of TDAA in Chukchi surface waters were relatively high, indicating an accumulation of bioavailable DOM. High concentrations and yields of TDAA were also observed in the upper halocline of slope and basin waters, indicating off-shelf transport of bioavailable DOM from the Chukchi Sea. In contrast, concentrations and yields of TDAA in Beaufort surface waters were relatively low, indicting DOM was of limited bioavailability. Concentrations and yields of TDAA in the upper halocline of slope and basin waters were also low, suggesting the Beaufort is not a major source of bioavailable DOM to slope and basin waters. In shelf waters of both systems, elevated concentrations and yields of TDAA were often observed in waters with higher chlorophyll concentrations and productivity. Surface concentrations of DOC were similar (p > 0.05) in the two systems despite the contrasting productivity, but concentrations and yields of TDAA were significantly higher (p < 0.0001) in the Chukchi than in the Beaufort. Unlike bulk DOC, TDAA concentrations and yields reflect ecosystem productivity in the western Arctic. The occurrence of elevated bioavailable DOM concentrations in the Chukchi Sea implies an uncoupling between the biological production and utilization of DOM and has important implications for sustaining heterotrophic microbial growth and diversity in oligotrophic waters of the central Arctic basins.

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“…[170,188] Understanding these seasonal and regional carbon sources is key as they will affect where and when Hg uptake will occur as well as enable the quantification of this pathway to higher trophic species. As the euphotic zone exhausts its nutrients the blooms collapse, giving a deep chlorophyll maximum where food production continues, [108,189] and carbon and associated Hg sources may become more accessible to other food webs such as the epibenthos or demersal food webs.…”

Section: Bottom Upmentioning

confidence: 99%

The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review

Douglas

Loseto²,

Macdonald³

et al. 2012

Environ. Chem.

Self Cite

119

147

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Environmental context. Mercury, in its methylated form, is a neurotoxin that biomagnifies in marine and terrestrial foodwebs leading to elevated levels in fish and fish-eating mammals worldwide, including at numerous Arctic locations. Elevated mercury concentrations in Arctic country foods present a significant exposure risk to Arctic people. We present a detailed review of the fate of mercury in Arctic terrestrial and marine ecosystems, taking into account the extreme seasonality of Arctic ecosystems and the unique processes associated with sea ice and Arctic hydrology.Abstract. This review is the result of a series of multidisciplinary meetings organised by the Arctic Monitoring and Assessment Programme as part of their 2011 Assessment 'Mercury in the Arctic'. This paper presents the state-of-the-art knowledge on the environmental fate of mercury following its entry into the Arctic by oceanic, atmospheric and terrestrial pathways. Our focus is on the movement, transformation and bioaccumulation of Hg in aquatic (marine and fresh water) and terrestrial ecosystems. The processes most relevant to biological Hg uptake and the potential risk associated with Hg exposure in wildlife are emphasised. We present discussions of the chemical transformations of newly deposited or transported Hg in marine, fresh water and terrestrial environments and of the movement of Hg from air, soil and water environmental compartments into food webs. Methylation, a key process controlling the fate of Hg in most ecosystems, and the role of trophic processes in controlling Hg in higher order animals are also included. Case studies on Eastern Beaufort Sea beluga (Delphinapterus leucas) and landlocked Arctic char (Salvelinus alpinus) are presented as examples of the relationship between ecosystem trophic processes and biologic Hg levels. We examine whether atmospheric mercury depletion events (AMDEs) contribute to increased Hg levels in Arctic biota and provide information on the links between organic carbon and Hg speciation, dynamics and bioavailability. Long-term sequestration of Hg into non-biological archives is also addressed. The review concludes by identifying major knowledge gaps in our understanding, including:(1) the rates of Hg entry into marine and terrestrial ecosystems and the rates of inorganic and MeHg uptake by Arctic microbial and algal communities; (2) the bioavailable fraction of AMDE-related Hg and its rate of accumulation by biota and (3) the fresh water and marine MeHg cycle in the Arctic, especially the marine MeHg cycle.

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Primary productivity and export fluxes on the Canadian shelf of the Beaufort Sea: A modelling study

Cited by 65 publications

References 65 publications

Role of sea ice in global biogeochemical cycles: emerging views and challenges

Role of sea ice in global biogeochemical cycles: emerging views and challenges

Dissolved organic matter composition and bioavailability reflect ecosystem productivity in the Western Arctic Ocean

The fate of mercury in Arctic terrestrial and aquatic ecosystems, a review

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