Bioactive trace metal time series during Austral summer in Ryder Bay, Western Antarctic Peninsula

• Published in: Deep Sea Research Part II: Topical Studies in Oceanography
• Main Authors: Bown, Johann, Laan, Patrick, Ossebaar, Sharyn, Bakker, Karel, Rozema, Patrick, de Baar, Hein J.W.
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2017
• Subjects: Antarctic; Antarctic Peninsula; Austral; Rothera; Ryder; Ryder Bay; Southern Ocean; Antarc*; British Antarctic Survey; Sea ice
• Online Access: https://hdl.handle.net/11370/317b2ee6-f056-4354-83e8-5984e2ab6b91; https://research.rug.nl/en/publications/317b2ee6-f056-4354-83e8-5984e2ab6b91; https://doi.org/10.1016/j.dsr2.2016.07.004; https://pure.rug.nl/ws/files/42215614/1_s2.0_S0967064516301862_main.pdf

The Western Antarctic Peninsula, one of the most productive regions of the Southern Ocean, is currently affected by the increasing of atmospheric and oceanic temperatures. For several decades, the Rothera Time Series (RaTS) site located in Ryder Bay has been monitored by the British Antarctic Survey and has shown long lasting phytoplankton summer blooms (over a month) that are likely driven by the length of the sea ice season. The dynamics of phytoplankton blooms in Ryder Bay may just as well be influenced by natural fertilization of iron and other bioactive trace metals due to the proximity of land, islands and glaciers. For the first time, temporal distributions in the surface layer (0–75 m depth) of six bioactive trace metals (dissolved: Fe, Mn, Zn, Cd, Cu and dissolved labile Co) have been investigated with high temporal and spatial resolution at the RaTS site during a total of ~2 and 3.5 months respectively, over two consecutive summers. Most of the studied trace elements showed wide ranges of concentrations and this dynamics appears to be driven by phytoplankton uptake, remineralization and occasional vertical mixing associated with storm episodes. The biological uptake of DMn, DZn, DCd, DCoL and DCu was proportional to uptake of phosphate and silicate, which was associated with weak to strong linear relationships depending on which phytoplankton bloom events was considered. This further suggests that the surface water distributions of these studied bio-active trace metals were mainly driven by biological uptake and remineralization during austral spring and summer in Ryder Bay. Even though DFe didn't show any strong relationship with phosphate, DFe decreasing concentrations during each bloom event suggest that Fe is a key essential element for phytoplankton in the area of study. The consistency of trace metals / nutrient ratios during two consecutive summers indicates that over-winter scavenging removal was slow relative to mixing. The increase of DCd/P and DCoL/P drawdown ratios during the two ...