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Aluminium in the North Atlantic Ocean and the Labrador Sea (GEOTRACES GA01 section): roles of continental inputs and biogenic particle removal
- Source :
- Biogeosciences, Vol 15, Pp 5271-5286 (2018)
- Publication Year :
- 2018
- Publisher :
- Copernicus Publications, 2018.
-
Abstract
- The distribution of dissolved aluminium (dAl) in the water column of the North Atlantic and Labrador Sea was studied along GEOTRACES section GA01 to unravel the sources and sinks of this element. Surface water dAl concentrations were low (median of 2.5 nM) due to low aerosol deposition and removal by biogenic particles (i.e. phytoplankton cells). However, surface water dAl concentrations were enhanced on the Iberian and Greenland shelves (up to 30.9 nM) due to continental inputs (rivers, glacial flour, and ice melt). Dissolved Al in surface waters scaled negatively with chlorophyll a and biogenic silica (opal) concentrations. The abundance of diatoms exerted a significant (p R2 > 0.76) west of the Iberian Basin, suggesting net release of dAl at depth during remineralization of sinking opal-containing particles. Enrichment of dAl at near-bottom depths was observed due to the resuspension of sediments. The highest dAl concentrations (up to 38.7 nM) were observed in Mediterranean Outflow Waters, which act as a major source of dAl to mid-depth waters of the eastern North Atlantic. This study clearly shows that the vertical and lateral distributions of dAl in the North Atlantic differ when compared to other regions of the Atlantic and global oceans. Responsible for these large inter- and intra-basin differences are the large spatial variabilities in the main Al source, atmospheric deposition, and the main Al sink, particle scavenging by biogenic particles.
Details
- Language :
- English
- ISSN :
- 17264170 and 17264189
- Volume :
- 15
- Database :
- Directory of Open Access Journals
- Journal :
- Biogeosciences
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.7f765957965c4519b0f07d2d5a7c6937
- Document Type :
- article
- Full Text :
- https://doi.org/10.5194/bg-15-5271-2018