Physical and biological controls on DMS,P dynamics in ice shelf-influenced fast ice during a winter-spring and a spring-summer transitions

Abstract

We report the seasonal and vertical variations of dimethylsulfide (DMS) and its precursor dimethylsulfoniopropionate (DMSP) in fast ice at Cape Evans, McMurdo Sound (Antarctica) during the springsummer transition in 2011 and winter-spring transition in 2012. We compare the variations of DMS,P observed to the seasonal evolution of the ice algal biomass and of the physical properties of the ice cover, with emphasis on the ice texture and brine dynamics. Isolated DMS and DMSP maxima were found during both seasonal episodes in interior ice and corresponded to the occurrence of platelet crystals in the ice texture. We show that platelet crystals formation corresponded in time and depth to the incorporation of dinoflagellates (strong DMSP producers) in the ice cover. We also show that platelet crystals could modify the environmental stresses on algal cells and perturb the vertical redistribution of DMS,P concentrations. We show that during the winter-spring transition in 2012, the DMS,P profiles were strongly influenced by the development and decline of a diatom-dominated bloom in the bottom ice, with DMSP variations remarkably following chl a variations. During the spring-summer transition in 2011, the increase in brine volume fraction (influencing ice permeability) on warming was shown to trigger (1) an important release of DMS to the under-ice water through brine convection and (2) a vertical redistribution of DMSP across the ice.

Chlorophyll‐a in Antarctic Landfast Sea Ice: A First Synthesis of Historical Ice Core Data

“…Historically, studies on Antarctic fast ice algal communities have focused primarily on the taxonomy and physiology of algae inhabiting high‐biomass microhabitats (Arrigo et al, ; Grossi et al, ; McMinn, Pankowskii, et al, ; Stoecker et al, ; Whitaker & Richardson, ). Time series studies have been conducted in specific regions but overall remain sparse (Carnat et al, ; Delille et al, ; Fiala et al, ; Günther & Dieckmann, ; Watanabe et al, ). Here we compiled a comprehensive database of ice algal Chl a concentrations from Antarctic fast‐ice cores collected from different regions around the continent.…”

Dimethyl sulfide dynamics in first-year sea ice melt ponds in the Canadian Arctic Archipelago

“…Keller et al, 1989;Stefels, 2000), environmental forcing are known to control DMSP, DMSO, and DMS concentrations. In ice-associated environments, brine volume fraction might also be key in explaining DMS cycling variability via the control of ice permeability (Carnat et al, 2014). Structural changes within sea ice during the melt season, namely increases in brine volume fraction and ice desalination, result in increased connectivity and permeability in the warming sea ice (Willis et al, 2016;Polashenski et al, 2012) and influence DMSP and DMS cycling Carnat et al, 2014).…”

“…In ice-associated environments, brine volume fraction might also be key in explaining DMS cycling variability via the control of ice permeability (Carnat et al, 2014). Structural changes within sea ice during the melt season, namely increases in brine volume fraction and ice desalination, result in increased connectivity and permeability in the warming sea ice (Willis et al, 2016;Polashenski et al, 2012) and influence DMSP and DMS cycling Carnat et al, 2014). Also, phytoplankton blooms developing under the ice during the melting period have been shown to produce large quantities of DMSP p , potentially leading to a build-up of DMS concentrations (Levasseur et al, 1994).…”

Brief Communication: Capturing scales of spatial heterogeneity of Antarctic sea ice algae communities

“…The lower 50 mm of each, plus attached platelets, was cut off using a stainless steel hacksaw, and transferred to a shore laboratory in a dark, insulated box for processing within 2 h. Previous studies have shown that this length of the cut section of the core contains the majority of the chla biomass (>99% authors' unpublished data; see also Ryan et al, 2006, Carnat et al, 2014. Cores were imaged and characteristics of the ice core, specifically the presence or absence of embedded 25 platelets, whether algae were primarily interstitial within the congelation ice or associated with platelets, and whether the core itself appeared to have been recovered with or without some degree of damage to the ice undersurface, was recorded.…”