Glacial meltwater from Greenland is not likely to be an important source of Fe to the North Atlantic

Hopwood, Mark J.; Bacon, Sheldon; Arendt, Kristine Engel; Connelly, Douglas P.; Statham, Peter J.

doi:10.1007/s10533-015-0091-6

Cited by 41 publications

(44 citation statements)

References 101 publications

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“…This suggests that the 'dissolved' flux of Fe from the GIS is not globally significant, consistent with the inferences of Hopwood et al (2015) and Zhang et al (2015). It is noteworthy that our flux estimate does not include either the contribution of labile Fe from glacial sediments or particulates >0.2 lm, which are the most significant source of labile Fe in meltwaters (e.g.…”

supporting

confidence: 77%

The iron isotopic composition of subglacial streams draining the Greenland ice sheet

Stevenson

Fantle

Das

et al. 2017

Geochimica et Cosmochimica Acta

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supporting

confidence: 77%

The iron isotopic composition of subglacial streams draining the Greenland ice sheet

Stevenson

Fantle

Das

et al. 2017

Geochimica et Cosmochimica Acta

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“…Seasonal Fe limitation has however been found in parts of the high latitude North Atlantic (Nielsdottir et al, 2009;Ryan-Keogh et al, 2013). As high concentrations of dissolved and particulate Fe have been reported in meltwater from the Greenland Ice Sheet (Statham et al, 2008;Bhatia et al, 2013b;Hawkings et al, 2014) and glaciers around parts of Antarctica have been demonstrated to supply Fe to adjacent polynyas Sherrell et al, 2015), there is a clear interest in determining whether or not increasing volumes of meltwater discharge from Greenland could affect Fe supply to offshore marine ecosystems (Yde et al, 2014;Aciego et al, 2015;Hopwood et al, 2015). As most calved ice melts within this fjord (Bendtsen et al, 2015), the summer outflow of the low salinity surface layer along Godthåbsfjord is the most likely direct export mechanism for the particulate and dissolved Fe in meltwater to coastal seas.…”

Section: Fe Input and Potential Export To Coastal Seasmentioning

confidence: 99%

Seasonal Changes in Fe along a Glaciated Greenlandic Fjord

et al. 2016

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Greenland's ice sheet is the second largest on Earth, and is under threat from a warming Arctic climate. An increase in freshwater discharge from Greenland has the potential to strongly influence the composition of adjacent water masses with the largest impact on marine ecosystems likely to be found within the glaciated fjords. Here we demonstrate that physical and chemical estuarine processes within a large Greenlandic fjord are critical factors in determining the fate of meltwater derived nutrients and particles, especially for non-conservative elements such as Fe. Concentrations of Fe and macronutrients in surface waters along Godthåbsfjord, a southwest Greenlandic fjord with freshwater input from six glaciers, changed markedly between the onset and peak of the meltwater season due to the development of a thin (<10 m), outflowing, low-salinity surface layer. Dissolved (<0.2 µm) Fe concentrations in meltwater entering Godthåbsfjord (200 nM), in freshly melted glacial ice (mean 38 nM) and in surface waters close to a land terminating glacial system (80 nM) all indicated high Fe inputs into the fjord in summer. Total dissolvable (unfiltered at pH <2.0) Fe was similarly high with concentrations always in excess of 100 nM throughout the fjord and reaching up to 5.0 µM close to glacial outflows in summer. Yet, despite the large seasonal freshwater influx into the fjord, Fe concentrations near the fjord mouth in the out-flowing surface layer were similar in summer to those measured before the meltwater season. Furthermore, turbidity profiles indicated that sub-glacial particulate Fe inputs may not actually mix into the outflowing surface layer of this fjord. Emphasis has previously been placed on the possibility of increased Fe export from Greenland as meltwater fluxes increase. Here we suggest that in-fjord processes may be effective at removing Fe from surface waters before it can be exported to coastal seas.

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“…In addition, the physical circulation in the oceans around Greenland is apparently not very effective at exporting Fe into offshore waters in the North Atlantic. Hence, glacial runoff from Greenland is not a major source of Fe to the North Atlantic Ocean as a whole (Hopwood et al, 2015).…”

Section: Nutrient Biogeochemistry and Export To The Oceansmentioning

confidence: 99%

“…We used the mean concentrations of truly dissolved and colloidal Fe to produce estimates of fluxes of potentially bioavailable Fe to the coastal waters around Greenland and Antarctica (Statham et al, 2008). It was now up to the oceanographers to decide what would be the fate of this material during mixing with sea water (Hopwood et al, 2014(Hopwood et al, , 2015. Concentrations of truly dissolved (<30 nM) amd colloidal (20-400 nM) Fe in runoff from Bristol Glacier, 1999 (modified from Statham et al, 2008).…”

Section: The First Good Data For Ice Sheet Runoffmentioning

confidence: 99%