Biological pump processes in the cryopelagic and hemipelagic Arctic Ocean: Canada Basin and Chukchi Rise

Honjo, Susumu; Krishfield, Richard A.; Eglinton, T. I.; Manganini, Steven J.; Kemp, John N.; Doherty, Kenneth W.; Hwang, Jeomshik; McKee, Theresa K.; Takizawa, Takeo

doi:10.1016/j.pocean.2010.02.009

Cited by 93 publications

(142 citation statements)

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“…[45] For the Arctic, first-order estimates suggest that over half (108 t year À1 , range 13 to 200 t year À1 ) of the THg losses from the Arctic Ocean occur via this pathway. [36] This process may not be important in the interior ocean due to the low inherent particle fluxes, [46] and it may be that lateral transport of sediment from the margins to the deep interior is an important pathway. [47] The effect of particle flux will be to reduce the residence time of deposited Hg in surface water to a period shorter than the residence time of the water.…”

Section: Since 1993 Prof Henrik Skov Has Worked As Principal Scientimentioning

confidence: 99%

“…The interior part of the Arctic Ocean is oligotrophic, supporting a low particle flux. [46,114] Therefore, the rate of removal of particulate Hg from the surface, an apparently important component of the global ocean Hg cycle, [45] may operate weakly in the central basin of the Arctic Ocean compared with other oceans. However, burial rates may be more important in Arctic continental shelf areas.…”

Section: Microbial Carbon Processing and Mercury In The Arcticmentioning

confidence: 99%

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

Douglas

Loseto²,

Macdonald³

et al. 2012

Environ. Chem.

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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Section: Since 1993 Prof Henrik Skov Has Worked As Principal Scientimentioning

confidence: 99%

Section: Microbial Carbon Processing and Mercury In The Arcticmentioning

confidence: 99%

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

Douglas

Loseto²,

Macdonald³

et al. 2012

Environ. Chem.

119

147

View full text Add to dashboard Cite

show abstract

“…These terrigenous biomarkers preserved in the sediments might derive from fluvial or eroded shoreline sedimentary organic matter that has been carried out offshore by advective particle transport, e.g. nepheloid layers (Forest et al, 2007;Honjo et al, 2010). Moreover, the inverse distribution between retene and α-amyrin (Fig.…”

Section: Transport and Fate Of Particulate Mattermentioning

confidence: 99%

Carbon sources in suspended particles and surface sediments from the Beaufort Sea revealed by molecular lipid biomarkers and compound-specific isotope analysis

et al. 2013

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Molecular lipid biomarkers (hydrocarbons, alcohols, sterols and fatty acids) and compound-specific isotope analysis of suspended particulate organic matter (SPM) and surface sediments of the Mackenzie Shelf and slope (southeast Beaufort Sea, Arctic Ocean) were studied in summer 2009. The concentrations of the molecular lipid markers, characteristic of known organic matter sources, were grouped and used as proxies to evaluate the relative importance of fresh algal, detrital algal, fossil, C₃ terrestrial plants, bacterial and zooplankton material in the organic matter (OM) of this area. Fossil and detrital algal contributions were the major fractions of the freshwater SPM from the Mackenzie River with ~34% each of the total molecular biomarkers. Fresh algal, C₃ terrestrial, bacterial and zooplanktonic components represented much lower percentages, 17, 10, 4 and <1%, respectively. In marine SPM from the Mackenzie slope, the major contributions were fresh and detrital algal components (>80%), with a minor contribution of fossil and C₃ terrestrial biomarkers. Characterization of the sediments revealed a major sink of refractory algal material mixed with some fresh algal material, fossil hydrocarbons and a small input of C₃ terrestrial sources. In particular, the sediments from the shelf and at the mouth of the Amundsen Gulf presented the highest contribution of detrital algal material (60–75%), whereas those from the slope contained the highest proportion of fossil (40%) and C₃ terrestrial plant material (10%). Overall, considering that the detrital algal material is marine derived, autochthonous sources contributed more than allochthonous sources to the OM lipid pool. Using the ratio of an allochthonous biomarker (normalized to total organic carbon, TOC) found in the sediments to those measured at the river mouth water, we estimated that the fraction of terrestrial material preserved in the sediments accounted for 30–40% of the total carbon in the inner shelf sediments, 17% in the outer shelf and Amundsen Gulf and up to 25% in the slope sediments. These estimates are low compared to other studies conducted 5–20 yr earlier, and they support the increase in primary production during the last decade mainly because of the increase in the number of ice-free days and due to the strength and persistence of winds favouring upwelling

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“…The export production of the central Arctic Ocean has, at least until recently, been very low (Anderson et al 2003), and probably among the lowest in the global ocean (Honjo et al 2010). The low level of new production in the central ocean is likely due to a weak supply of nutrients to interior surface water, because these tend to be consumed in the shelf seas.…”

mentioning

confidence: 99%

“…Of course, there is some productivity in the water column, as well as within the sea ice and by algae hanging from the sea ice (e.g., Wheeler et al 1996;Krembs et al 2011). However, the majority of this produced organic matter is not sedimented deep in the water column before becoming degraded by microbes (Honjo et al 2010;O'Brien et al 2013;Ericson et al 2014) The near-absence of a labile particulate organic flux into the Arctic Ocean's basins is proven by the near constant concentrations of oxygen and nutrients in the water column from depths of a few hundred metres down to the bottom, nearly 4 km deep in Fig. 2 Carbon transformation by marine primary production followed by sedimentation and microbial decay.…”

mentioning

confidence: 99%