Chromium biogeochemistry and stable isotope distribution in the Southern Ocean ...

• Main Authors: Rickli, Jörg, Janssen, David J., Hassler, Christel, Ellwood, Michael J., Jaccard, Samuel L.
• Format: Text
• Language: English
• Published: ETH Zurich 2019
• Subjects: Seawater; Chromium isotopes; Southern Ocean; Antarctic; The Antarctic; Antarctic Peninsula; Drake Passage; Balleny Islands; Mertz Glacier; Antarc*; Antarctica
• Online Access: https://dx.doi.org/10.3929/ethz-b-000367419; http://hdl.handle.net/20.500.11850/367419

Despite the potential of stable chromium (Cr) isotope compositions as a proxy for past changes in oceanic redox conditions, a detailed understanding of the processes that govern their spatial distribution in the modern ocean is still lacking. Here, we report seawater Cr isotope compositions and concentrations from the uppermost 1000 m of the water column in the Southern Ocean. The survey includes a cross-frontal transect from Tasmania to Antarctica, sites near the Antarctic ice-edge and in the vicinity of the Balleny Islands, as well as sites in the Drake Passage. Although a coastal influence is clearly visible in the silicon-nitrate relationship at the stations neighbouring the Balleny Islands, close to the Mertz Glacier and adjacent to the western Antarctic Peninsula, seawater δ53Cr and Cr concentrations remain largely unaffected. As for the coastal sites, Cr depletion and isotopic shifts are also virtually absent in Antarctic and Subantarctic surface waters of the open ocean. Biological uptake of Cr ... : Geochimica et Cosmochimica Acta, 262 ...