Dissolved, Labile, and Total Particulate Trace Metal Dynamics on the Northeast Greenland Shelf

Chen, Xue-Gang1,2; Krisch, Stephan2,3; Al-Hashem, Ali2; Hopwood, Mark James4; van der Loeff, Michiel M. Rutgers5; Huhn, Oliver6; Lodeiro, Pablo7; Steffens, Tim2; Achterberg, Eric P.2

2022-12-01

10.1029/2022GB007528

GLOBAL BIOGEOCHEMICAL CYCLES   Impact Factor & Quartile

0886-6236

1944-9224

["We present high-resolution profiles of dissolved, labile, and total particulate trace metals (TMs) on the Northeast Greenland shelf from GEOTRACES cruise GN05 in August 2016. Combined with radium isotopes, stable oxygen isotopes, and noble gas measurements, elemental distributions suggest that TM dynamics were mainly regulated by the mixing between North Atlantic-derived Intermediate Water, enriched in labile particulate TMs (LpTMs), and Arctic surface waters, enriched in Siberian shelf-derived dissolved TMs (dTMs; Co, Cu, Fe, Mn, and Ni) carried by the Transpolar Drift. These two distinct sources were delineated by salinity-dependent variations of dTM and LpTM concentrations and the proportion of dTMs relative to the total dissolved and labile particulate ratios. Locally produced meltwater from the Nioghalvfjerdsbrae (79NG) glacier cavity, distinguished from other freshwater sources using helium excess, contributed a large pool of dTMs to the shelf inventory. Localized peaks in labile and total particulate Cd, Co, Fe, Mn, Ni, Cu, Al, V, and Ti in the cavity outflow, however, were not directly contributed by submarine melting. Instead, these particulate TMs were mainly supplied by the re-suspension of cavity sediment particles. Currently, Arctic Ocean outflows are the most important source of dFe, dCu, and dNi on the shelf, while LpTMs and up to 60% of dMn and dCo are mainly supplied by subglacial discharge from the 79NG cavity. Therefore, changes in the cavity-overturning dynamics of 79NG induced by glacial retreat, and alterations in the transport of Siberian shelf-derived materials with the Transport Drift may shift the shelf dTM-LpTM stoichiometry in the future.","Plain Language Summary Trace metals (TMs) including cobalt (Co), iron (Fe), manganese (Mn), copper (Cu), and nickel (Ni) are essential micronutrients for marine productivity. The Northeast Greenland shelf is a climatically sensitive region, influenced by both outflowing Arctic waters and local glacier melting. We lack knowledge on how these Arctic surface waters affect TM dynamics on the Greenland shelf and how climatic shifts may influence TM dynamics. Here, we distinguish local submarine meltwater from Arctic surface waters using distinct tracers; noble gases and radium isotopes. We show that the TM dynamics on the shelf are largely controlled by the intrusion of Arctic surface waters which creates a near-surface plume of dissolved and labile particulate TMs. Conversely, submarine meltwater creates a subsurface plume enriched in dissolved TMs but depleted in particulate TMs, which is exported from underneath a floating ice tongue. In the future, increasing Arctic river discharge and local glacial melting may both significantly change shelf micronutrient ratios demonstrating downstream impacts of a changing cryosphere on marine biogeochemical cycles."]

Arctic trace metals labile particulate glacier meltwater GEOTRACES

SCI

English

Others

Deutsche Forschungsgemeinschaft[AC 217/1-1] ; DFG[HO 6321/1-1]

Environmental Sciences & Ecology ; Geology ; Meteorology & Atmospheric Sciences

Environmental Sciences ; Geosciences, Multidisciplinary ; Meteorology & Atmospheric Sciences

WOS:000924596500001

AMER GEOPHYSICAL UNION

GEOSCIENCES

Web of Science

1.Zhejiang Univ, Ocean Coll, Zhoushan, Peoples R China
2.GEOMAR Helmholtz Ctr Ocean Res Kiel, Kiel, Germany
3.Bundesanstalt Gewasserkunde, Koblenz, Germany
4.Southern Univ Sci & Technol, Dept Ocean Sci & Engn, Shenzhen, Peoples R China
5.Helmholtz Ctr Polar & Marine Res, Alfred Wegener Inst, Bremerhaven, Germany
6.Univ Bremen, IUP Inst Environm Phys, Bremen, Germany
7.Univ Lleida AGROTECNIO CERCA, Dept Chem, Lleida, Spain

Chen, Xue-Gang,Krisch, Stephan,Al-Hashem, Ali,et al. Dissolved, Labile, and Total Particulate Trace Metal Dynamics on the Northeast Greenland Shelf[J]. GLOBAL BIOGEOCHEMICAL CYCLES,2022,36(12).

Chen, Xue-Gang.,Krisch, Stephan.,Al-Hashem, Ali.,Hopwood, Mark James.,van der Loeff, Michiel M. Rutgers.,...&Achterberg, Eric P..(2022).Dissolved, Labile, and Total Particulate Trace Metal Dynamics on the Northeast Greenland Shelf.GLOBAL BIOGEOCHEMICAL CYCLES,36(12).

Chen, Xue-Gang,et al."Dissolved, Labile, and Total Particulate Trace Metal Dynamics on the Northeast Greenland Shelf".GLOBAL BIOGEOCHEMICAL CYCLES 36.12(2022).