(2020) Carbon Mineralization Pathways in Antarctic Shelf Sediments, East Antarctic Peninsula
Baloza M, Henkel S, Kasten S & Holtappels M
12c: Plenary Hall, Wednesday 24th June 22:06 - 22:09
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You started your talk suggesting that the warming of the region could change the processes. Of course this area has already experienced significant changes already. You saw a clear transition in processes as you moved from ice dominated to ice free zones, but was there any evidence that these processes have changed over time?
Thanks Christopher for your question. It has been hypothesized that biological production along the Antarctic peninsula is primarily controlled by light availability. The thinning of sea ice cover could favor surface primary production. These changes will likely induce shifts in carbon flux which will directly affect the rates and pathways of benthic carbon cycle.
Hi Marwa, I was particularly interested in your measurements of Fe efflux from the sediments. Your slide 9 suggests that polynyas, which are defined by their low sea ice concentrations, should have relatively large Fe efflux values and high concentrations of dissolved Fe in the ocean bottom layer. This qualitatively matches what we see in the Amundsen Sea Polynya (Sherrell et al.2015). Modelers are struggling to parameterize this Fe efflux from sediments and sometimes rely on data from completely different environments. Apart from your own study, are you familiar with other studies that directly measured Fe efflux on Antarctic continental shelves? Cheers, Pierre (firstname.lastname@example.org)
Thanks Pierre for your question. There is paper by (Monien et al, 2014) he calculated the Fe flux from Poter Cove sediments. And another interesting one by (Susann Henkel et al, 2018) about iron cycling and stable Fe isotope fractionation in Antarctic shelf sediments, King George Island
Hi Maria, I'm wondering why H2S and SO4 both increase with depth at station 7 (<40% ice coverage).
Thanks Fei Da for your questions. Sulfate profiles doesn't show the concentration, it shows the sulfate depletion (SO4 2- dep) in pore water which reflects the net amount of sulfate consumption via microbial sulfate reduction. And it's increasing with depth at St4 and St7 which is logic. High H2S means high sulfate consumption.
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