The role of sea ice formation in cycling of aluminium in northern Marguerite Bay, Antarctica
Hendry, Katharine R.
Meredith, Michael P.
Measures, Christopher I.
Carson, Damien S.
Rickaby, Rosalind E. M.
MetadataShow full item record
The use of dissolved Al as a tracer for oceanic water masses and atmospheric dust deposition of biologically important elements, such as iron, requires the quantitative assessment of its sources and sinks in seawater. Here, we address the relative importance of oceanic versus atmospheric inputs of Al, and the relationship with nutrient cycling, in a region of high biological productivity in coastal Antarctica. We investigate the concentrations of dissolved Al in seawater, sea ice, meteoric water and sediments collected from northern Marguerite Bay, off the West Antarctic Peninsula, from 2005-2006. Dissolved Al concentrations at 15 m water depth varied between 2 and 27 nM, showing a peak between two phytoplankton blooms. We find that, in this coastal setting, upwelling and incorporation of waters from below the surface mixed layer are responsible for this peak in dissolved Al as well as renewal of nutrients. This means that changes in the intensity and frequency of upwelling events may result in changes in biological production and carbon uptake. The waters below the mixed layer are most likely enriched in Al as a result of sea ice formation, either causing the injection of Al-rich brines or the resuspension of sediments and entrainment of pore fluids by brine cascades. Glacial, snow and sea ice melt contributes secondarily to the supply of Al to surface waters. Total particulate Al ranges from 93 to 2057 μg/g, and increases with meteoric water input towards the end of the summer, indicating glacial runoff is an important source of particulate Al. The (Al/Si)opal of sediment core top material is considerably higher than water column opal collected by sediment traps, indicative of a diagenetic overprint and incorporation of Al at the sediment-water interface. Opal that remains buried in the sediment could represent a significant sink of Al from seawater.
Author Posting. © The Author(s), 2009. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Estuarine, Coastal and Shelf Science 87 (2010): 103-112, doi:10.1016/j.ecss.2009.12.017.
Showing items related by title, author, creator and subject.
Spatial and isotopic niche partitioning during winter in chinstrap and Adélie penguins from the South Shetland Islands Hinke, Jefferson T.; Polito, Michael J.; Goebel, Michael E.; Jarvis, Sharon; Reiss, Christian S.; Thorrold, Simon R.; Trivelpiece, Wayne Z.; Watters, George M. (Ecological Society of America, 2015-07-29)Closely related species with similar ecological requirements should exhibit segregation along spatial, temporal, or trophic niche axes to limit the degree of competitive overlap. For migratory marine organisms like seabirds, ...
Top predators in relation to bathymetry, ice and krill during austral winter in Marguerite Bay, Antarctica Ribic, Christine A.; Chapman, Erik; Fraser, William R.; Lawson, Gareth L.; Wiebe, Peter H. (2007-03-15)A key hypothesis guiding the U.S. Southern Ocean Global Ocean Ecosystems Dynamics (U.S. SO GLOBEC) program is that deep across-shelf troughs facilitate the transport of warm and nutrient-rich waters onto the continental ...
Microbial diversity and community structure across environmental gradients in Bransfield Strait, Western Antarctic Peninsula Signori, Camila N.; Thomas, Francois; Enrich-Prast, Alex; Pollery, Ricardo C. G.; Sievert, Stefan M. (Frontiers Media, 2014-12-16)The Southern Ocean is currently subject to intense investigations, mainly related to its importance for global biogeochemical cycles and its alarming rate of warming in response to climate change. Microbes play an essential ...