Abstract
Iron (Fe) is an essential micronutrient for phytoplankton, and is scarce in many regions including the open Southern Ocean. The western Antarctic Peninsula (WAP), an important source region of Fe to the wider Southern Ocean, is also the fastest warming region of the Southern Hemisphere. The relative importance of glacial versus marine Fe sources is currently poorly constrained, hindering projections of how changing oceanic circulation, productivity, and glacial dynamics may affect the balance of Fe sources in this region.
Dissolved and total dissolvable Fe concentrations were measured throughout the summer bloom period at a coastal site on the WAP. Iron inputs to the surface mixed layer in early summer were strongly correlated with meteoric
meltwater from glaciers and precipitation. A significant source of Fe from underlying waters was also identified, with dissolved Fe concentrations of up to 9.5 nM at 200 m depth. These two primary Fe sources act on different timescales, with glacial sources supplying Fe during the warm summer growing period, and deep water replenishing Fe over annual periods via deep winter mixing.
Iron supply from deep water is sufficient to meet biological demand relative to macronutrient supply, making Fe limitation unlikely in this area even without additional summer Fe inputs from glacial sources. Both glacial and deep-water Fe sources may increase with continued climate warming, potentially enhancing the role of the WAP as an Fe source to offshore waters.
Dissolved and total dissolvable Fe concentrations were measured throughout the summer bloom period at a coastal site on the WAP. Iron inputs to the surface mixed layer in early summer were strongly correlated with meteoric
meltwater from glaciers and precipitation. A significant source of Fe from underlying waters was also identified, with dissolved Fe concentrations of up to 9.5 nM at 200 m depth. These two primary Fe sources act on different timescales, with glacial sources supplying Fe during the warm summer growing period, and deep water replenishing Fe over annual periods via deep winter mixing.
Iron supply from deep water is sufficient to meet biological demand relative to macronutrient supply, making Fe limitation unlikely in this area even without additional summer Fe inputs from glacial sources. Both glacial and deep-water Fe sources may increase with continued climate warming, potentially enhancing the role of the WAP as an Fe source to offshore waters.
Original language | English |
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Pages (from-to) | 21-33 |
Journal | Marine Chemistry |
Volume | 176 |
Early online date | 27 Jun 2015 |
DOIs | |
Publication status | Published - 20 Nov 2015 |
Keywords / Materials (for Non-textual outputs)
- Iron
- Aluminium
- Iron budget
- Glacial input
- Upwelling
- Ryder Bay
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Inductively Coupled Plasma - Optical Emission Spectrometry Laboratory and Mass Spectrometry Laboratories (ICP)
Pichevin, L. (Manager)
School of GeosciencesFacility/equipment: Facility
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Oceanography Clean Laboratory (OCL)
Pichevin, L. (Manager)
School of GeosciencesFacility/equipment: Facility
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Oceanography Open Laboratory (OOL)
Thomas, A. (Manager)
School of GeosciencesFacility/equipment: Facility
Profiles
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Raja Ganeshram
- School of Geosciences - Personal Chair of Geochemistry
Person: Academic: Research Active