EGU2020-7528
https://doi.org/10.5194/egusphere-egu2020-7528
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Impact of glacial meltwater on biogeochemical cycling in coastal and shelf waters off South West Greenland: Insights from ship-board and glider observations

Katharine Hendry1, Nathan Briggs2, Jacob Opher3,4, J. Alexander Brearley3, Michael Meredith3, Melanie Leng5, E. Malcolm Woodward6, and Stephanie Henson2
Katharine Hendry et al.
  • 1School of Earth Sciences, University of Bristol, Wills Memorial Building, Queen’s Road, Bristol, BS8 1RJ, UK (k.hendry@bristol.ac.uk)
  • 2National Oceanography Centre Southampton, European Way, Southampton, SO14 3ZH, UK
  • 3British Antarctic Survey, High Cross, Madingley Road, Cambridge, CB3 0ET, UK
  • 4School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
  • 5NERC Isotope Geosciences Facility, British Geological Survey, Keyworth, Nottingham, NG12 3GG, UK
  • 6Plymouth Marine Laboratory, Prospect Place, The Hoe, Plymouth, PL1 3DH, UK

The high-latitude regions are experiencing some of the most rapid environmental changes observed anywhere on Earth, especially in recent years. The Greenland Ice Sheet, for example, is experiencing significant mass loss largely through surface melting, but also via ice discharge at glacier fronts. As well as changing freshwater budgets and ocean stratification and mixing, there has been increasing focus on the role of glaciers and ice sheets in supplying particulate and dissolved organic material and inorganic nutrients to marine systems. Here, we explore how a combination of ship-board and high-resolution ocean glider observations in shelf waters off SW Greenland inform on how these nutrients reach the coastal oceans and, eventually, mix off the shelf and into the open ocean. We find that the proportion of meltwater calculated using salinity and oxygen isotope mass balance agrees well with estimates from glider sensors. These meltwaters contain low dissolved macronutrients, but are characterised by high particulate and high dissolved organic content. Bio-optic sensors on the gliders reveal strong meltwater signals in fluorescing dissolved organic matter (FDOM), and a detectable signal in optical backscatter; these signals can be now observed extending further out into the open ocean in compiled biogeochemical (BGC) argo float data. The mixing of both dissolved and particulate macronutrients and organic matter off the shelf is likely driven by advection in geostrophic currents, tidal and buoyancy forcing, and is also impacted by storm events via wind-driven changes in mixed layer depth and resuspension.

How to cite: Hendry, K., Briggs, N., Opher, J., Brearley, J. A., Meredith, M., Leng, M., Woodward, E. M., and Henson, S.: Impact of glacial meltwater on biogeochemical cycling in coastal and shelf waters off South West Greenland: Insights from ship-board and glider observations, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-7528, https://doi.org/10.5194/egusphere-egu2020-7528, 2020

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