Elevated sources of cobalt in the Arctic Ocean DOI Creative Commons
Randelle M. Bundy, Alessandro Tagliabue, Nicholas J. Hawco

et al.

Biogeosciences, Journal Year: 2020, Volume and Issue: 17(19), P. 4745 - 4767

Published: Oct. 1, 2020

Abstract. Cobalt (Co) is an important bioactive trace metal that the cofactor in cobalamin (vitamin B12) which can limit or co-limit phytoplankton growth many regions of ocean. Total dissolved and labile Co measurements Canadian sector Arctic Ocean during U.S. GEOTRACES expedition (GN01) International Polar Year (GIPY14) revealed a dynamic biogeochemical cycle for this basin. The major sources were from shelf rivers, with only minimal contributions other freshwater (sea ice, snow) eolian deposition. most striking feature was extremely high concentrations upper 100 m, routinely exceeding 800 pmol L−1 over regions. This plume persisted throughout basin extended to North Pole, where shifted primarily shelf-derived riverine, as rivers entrained Transpolar Drift. Dissolved also strongly organically complexed Arctic, ranging 70 % surface deep ocean, respectively. Deep-water remarkably consistent (∼55 L−1), reflecting those Atlantic water deep-ocean scavenging Co. A model cycling used support hypothesis majority emanating shelf. showed observed due large area well dampened by manganese-oxidizing (Mn-oxidizing) bacteria lower temperatures. appears have occurred 200 additional below depth. Evidence suggests both (dCo) (LCo) are increasing time on shelf, these limited temporal results tracers Arctic. These elevated likely lead net flux out implications downstream biological uptake Deep Water. Understanding current distributions will be constraining changes inputs resulting regional intensification fluxes ice permafrost melt response ongoing climate change.

Language: Английский

Arctic methylmercury cycling DOI Creative Commons
Sofi Jonsson,

Michelle Nerentorp Mastromonaco,

Fei Wang

et al.

The Science of The Total Environment, Journal Year: 2022, Volume and Issue: 850, P. 157445 - 157445

Published: July 23, 2022

Anthropogenic mercury (Hg) undergoes long-range transport to the Arctic where some of it is transformed into methylmercury (MeHg), potentially leading high exposure in inhabitants and wildlife. The environmental Hg determined not just by amount entering Arctic, but also biogeochemical ecological processes occurring Arctic. These affect MeHg uptake biota regulating bioavailability, methylation demethylation, bioaccumulation biomagnification ecosystems. Here, we present a new budget for pools fluxes review scientific advances made last decade on Hg. Methylation demethylation are key controlling pool available bioaccumulation. occurs diverse environments including permafrost, sediments ocean water column, primarily process carried out microorganisms. While microorganisms carrying hgcAB gene pair (responsible methylation) have been identified soils thawing formation pathway oxic marine waters remains less clear. Hotspots terrestrial include thermokarst wetlands, ponds lakes. shallow sub-surface enrichment Ocean, comparison other systems, possible explanation concentrations biota. Bioconcentration aqueous bacteria algae critical step transfer top predators, which may be dampened or enhanced presence organic matter. Variable trophic position has an important influence among populations predator species such as ringed seal polar bears distributed across circumpolar highlight that fate anthropogenic deposited environments.

Language: Английский

Citations

28
What are the likely changes in mercury concentration in the Arctic atmosphere and ocean under future emissions scenarios? DOI
Amina T. Schartup, Anne L. Soerensen, Hélène Angot

et al.

The Science of The Total Environment, Journal Year: 2022, Volume and Issue: 836, P. 155477 - 155477

Published: April 23, 2022

Language: Английский

Citations

24
A river of terrestrial dissolved organic matter in the upper waters of the central Arctic Ocean DOI
Mohamed Gamrani,

Jane Eert,

William J. Williams

et al.

Deep Sea Research Part I Oceanographic Research Papers, Journal Year: 2023, Volume and Issue: 196, P. 104016 - 104016

Published: Feb. 28, 2023

Language: Английский

Citations

14
The Eurasian Arctic Ocean along the MOSAiC drift in 2019–2020: An interdisciplinary perspective on physical properties and processes DOI Creative Commons
Kirstin Schulz, Zoé Koenig, Morven Muilwijk

et al.

Elementa Science of the Anthropocene, Journal Year: 2024, Volume and Issue: 12(1)

Published: Jan. 1, 2024

The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC, 2019–2020), a year-long drift with sea ice, has provided scientific community an unprecedented, multidisciplinary dataset from Eurasian Ocean, covering high atmosphere to deep ocean across all seasons. However, heterogeneity data and superposition spatial temporal variability, intrinsic campaign, complicate interpretation observations. In this study, we have compiled quality-controlled physical hydrographic best spatio-temporal coverage derived core parameters, including mixed layer depth, heat fluxes over key layers, friction velocity. We provide comprehensive accessible overview conditions encountered along MOSAiC drift, discuss their interdisciplinary implications, compare common climatologies these new data. Our results indicate that, most part, variability was dominated by regional rather than seasonal signals, carrying potentially strong implications biogeochemistry, ecology, even atmospheric conditions. Near-surface properties were strongly influenced relative position sampling, within or outside river-water Transpolar Drift, warming meltwater input. Ventilation down Atlantic Water in Nansen Basin allowed stronger connectivity between subsurface ice surface via elevated upward fluxes. Yermak Plateau Fram Strait regions characterized heterogeneous water mass distributions, energetic currents, lateral gradients frontal regions. Together presented offer context research, fostering improved understanding complex, coupled System.

Language: Английский

Citations

6
Climate change driven effects on transport, fate and biogeochemistry of trace element contaminants in coastal marine ecosystems DOI Creative Commons
Rebecca Zitoun, Saša Marcinek, Vanessa Hatje

et al.

Communications Earth & Environment, Journal Year: 2024, Volume and Issue: 5(1)

Published: Oct. 4, 2024

Language: Английский

Citations

6
GEOTRACES: Ironing Out the Details of the Oceanic Iron Sources? DOI Creative Commons
Tim M. Conway, Rob Middag, Reiner Schlitzer

et al.

Oceanography, Journal Year: 2024, Volume and Issue: 37(2)

Published: Jan. 1, 2024

Dissolved iron (dFe) is an essential micronutrient for phytoplankton, with vanishingly low oceanic dissolved concentrations (pico- to nanomoles per kg) known limit growth—and thus influence primary productivity and carbon cycling—over much of the surface ocean. However, because considerable challenges associated contamination-free sample collection accurate analysis such dFe concentrations, first reliable measurements came only in 1980s. Further, by 2003, despite several decades research, there were ~25 full-depth profiles worldwide, dust considered be main source. Since 2008, facilitated extensive field campaign rigorous intercalibration international GEOTRACES program, has been “explosion” availability data, hundreds now available. Concurrently, a paradigm shift view marine Fe cycle where multiple sources contribute, some forms can transported great distances through intermediate deep Here, we showcase datasets across different ocean basins, synthesize our current multi-source cycle, spotlight sediments as important source, look future directions constraining boundary exchange.

Language: Английский

Citations

5
The influence of Arctic Fe and Atlantic fixed N on summertime primary production in Fram Strait, North Greenland Sea DOI Creative Commons
Stephan Krisch, Thomas J. Browning, Martin Graeve

et al.

Scientific Reports, Journal Year: 2020, Volume and Issue: 10(1)

Published: Sept. 17, 2020

Abstract Climate change has led to a ~ 40% reduction in summer Arctic sea-ice cover extent since the 1970s. Resultant increases light availability may enhance phytoplankton production. Direct evidence for factors currently constraining summertime growth region is however lacking. GEOTRACES cruise GN05 conducted Fram Strait transect from Svalbard NE Greenland Shelf 2016, sampling bioessential trace metals (Fe, Co, Zn, Mn) and macronutrients (N, Si, P) at 79°N. Five bioassay experiments were establish responses additions of Fe, N, Fe + N volcanic dust. Ambient nutrient concentrations suggested deficient surface seawater relative typical requirements. A west-to-east trend deficiency was apparent, with becoming more towards Svalbard. This aligned experiments, which showed greatest chlorophyll-a treatment near Collectively these results suggest primary limitation throughout study region, conditions potentially approaching secondary eastern Strait. We that supply Atlantic-derived Arctic-derived exerts strong control on stoichiometry resultant patterns across region.

Language: Английский

Citations

34
Separating individual contributions of major Siberian rivers in the Transpolar Drift of the Arctic Ocean DOI Creative Commons
Ronja Paffrath, Georgi Laukert, Dorothea Bauch

et al.

Scientific Reports, Journal Year: 2021, Volume and Issue: 11(1)

Published: April 15, 2021

Abstract The Siberian rivers supply large amounts of freshwater and terrestrial derived material to the Arctic Ocean. Although riverine constituents have been identified in central Ocean, individual contributions their spatiotemporal distributions Transpolar Drift (TPD), major wind-driven current Eurasian sector are unknown. Determining influence downstream TPD, however, is critical forecast responses polar sub-polar hydrography biogeochemistry anticipated changes river discharge composition. Here, we identify from largest systems, Lena Yenisei/Ob, TPD using dissolved neodymium isotopes rare earth element concentrations. We further demonstrate vertical lateral separation that likely due distinct temporal emplacements Yenisei/Ob waters as well prior mixing water with ambient waters.

Language: Английский

Citations

31
Structure and Inter-Annual Variability of the Freshened Surface Layer in the Laptev and East-Siberian Seas During Ice-Free Periods DOI Creative Commons
Alexander Osadchiev, D. I. Frey, Eduard Spivak

et al.

Frontiers in Marine Science, Journal Year: 2021, Volume and Issue: 8

Published: Dec. 10, 2021

This work is focused on the structure and inter-annual variability of freshened surface layer (FSL) in Laptev East-Siberian seas during ice-free periods. formed mainly by deltaic rivers among which Lena River contributes about two thirds inflowing freshwater volume. Based situ measurements, we show that area this FSL certain years much greater than neighboring Kara Sea, while total annual discharge to 1.5 times less Sea (mainly from estuaries Ob Yenisei rivers). feature caused differences morphology deltas. Shallow narrow channels Delta are limitedly affected sea water. As a result, undiluted inflows multiple forms relatively shallow plume, as compared Ob-Yenisei mixes with subjacent saline water deep wide estuaries. Due small vertical extents seas, wind conditions strongly affect its spreading determine significant variability, stable Sea. During prevailing western northern winds, localized southern parts due southward Ekman transport, meridional extent (<250 km) (∼250,000 km 2 ) small. strong eastern winds spreads northward over large (up 500,000 ), increases up 500–700 km. At same time, position do not any dependence river volume ice coverage warm season.

Language: Английский

Citations

30
Arctic – Atlantic Exchange of the Dissolved Micronutrients Iron, Manganese, Cobalt, Nickel, Copper and Zinc With a Focus on Fram Strait DOI Creative Commons
Stephan Krisch, Mark J. Hopwood,

Stéphane Roig

et al.

Global Biogeochemical Cycles, Journal Year: 2022, Volume and Issue: 36(5)

Published: May 1, 2022

Abstract The Arctic Ocean is considered a source of micronutrients to the Nordic Seas and North Atlantic through gateway Fram Strait (FS). However, there paucity trace element data from across gateways, so it remains unclear how exchange shapes micronutrient availability in two ocean basins. In 2015 2016, GEOTRACES cruises sampled Barents Sea Opening (GN04, 2015) FS (GN05, 2016) for dissolved iron (dFe), manganese (dMn), cobalt (dCo), nickel (dNi), copper (dCu) zinc (dZn). Together with most recent synopsis Arctic‐Atlantic volume fluxes, observed distributions suggest that important as consequence Intermediate Deep Water transport. Combining fluxes estimates Davis (GN02, suggests an annual net southward flux 2.7 ± 2.4 Gg·a −1 dFe, 0.3 dCo, 15.0 12.5 dNi 14.2 6.9 dCu toward Ocean. dMn dZn were more balanced, southbound 2.8 4.7 northbound 3.0 7.3 dZn. Our results ongoing changes shelf inputs sea ice dynamics Arctic, especially Siberian regions, affect high latitude

Language: Английский

Citations

19