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Hatton, JE, Ng, HC, Meire, L, Woodward, EMS, Leng, MJ, Coath, CD, Stuart‐Lee, A, Wang, T, Annett, AL and Hendry, KR 2023 Silicon Isotopes Highlight the Role of Glaciated Fjords in Modifying Coastal Waters. Journal of Geophysical Research: Biogeosciences, 128 (7). https://doi.org/10.1029/2022JG007242
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JGR Biogeosciences - 2023 - Hatton - Silicon Isotopes Highlight the Role of Glaciated Fjords in Modifying Coastal Waters.pdf - Published Version Available under License Creative Commons Attribution. Download (1MB) | Preview |
Abstract/Summary
Glaciers and ice sheets are experiencing rapid warming under current climatic change and there is increasing evidence that glacial meltwaters provide key dissolved and dissolvable amorphous nutrients to downstream ecosystems. However, large debate exists around the fate of these nutrients within complex and heterogenous fjord environments, where biogeochemical cycling is still often poorly understood. We combine silicon (Si) concentration data with isotopic compositions to better understand silicon cycling and export in two contrasting fjordic environments in south-west Greenland. We show that both fjords have isotopically light dissolved silicon (DSi) within surface waters, despite an apparently rapid biological drawdown of DSi with increasing salinity. We hypothesize that such observations cannot be explained by simple water mass mixing processes, and postulate that an isotopically light source of Si, most likely glacially derived amorphous silica (ASi), is responsible for further modifying these coastal waters within the fjords and beyond. Fjord to coastal exchange is likely a relatively slow process (several months), and thus is less impacted by short-term (<seasonal) changes of glacial meltwater input into the fjord, which has implications when considering the role of glacial meltwaters on nutrient export beyond the shelf break. We highlight the need for isotopic studies combined with dissolved and particulate nutrient concentration analysis to provide a more detailed analysis into the biogeochemical cycles within these highly dynamic fjord environments.
| Item Type: | Publication - Article |
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| Additional Keywords: | • Fjords have isotopically light dissolved silicon (DSi) in surface waters, despite an apparently rapid biological drawdown of DSi • Silicon isotope geochemistry is a vital tool for disentangling complex fjord biogeochemical processes • An isotopically light source of Si is responsible for modifying coastal waters within the fjords and beyond |
| Divisions: | Plymouth Marine Laboratory > Science Areas > Marine Biochemistry and Observations |
| Depositing User: | S Hawkins |
| Date made live: | 03 Oct 2023 13:52 |
| Last Modified: | 03 Oct 2023 13:52 |
| URI: | https://plymsea.ac.uk/id/eprint/10033 |
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