Carnat Gauthier, Said-Ahmad Ward, Fripiat François, Wittek Boris, Tison Jean-Louis, Uhlig Christiane, Amrani Alon
1Laboratoire de Glaciologie, Université Libre de Bruxelles, Brussels, B-1050 Belgium.
2Institute of Earth Science, The Hebrew University of Jerusalem, Jerusalem, 91904 Israel.
Commun Biol. 2018 Dec 4;1:212. doi: 10.1038/s42003-018-0228-y. eCollection 2018.
Sea ice microbial communities produce large amounts of the sulfur metabolite dimethylsulfoniopropionate (DMSP), a precursor of the climate cooling gas dimethylsulfide. Despite their importance to the polar sulfur cycle, drivers and metabolic pathways of sea ice DMSP are uncertain. Here we report the first measurements of sea ice DMSP sulfur isotopic composition (S/S ratio, δS). δS values in ice cores from the Ross Sea and Weddell Sea reveal considerable variability across seasons and between ice horizons (from +10.6 to +23.6‰). We discuss how the most extreme δS values observed could be related to unique DMSP cycling in the seasonally extreme physiochemical conditions of isolated brine inclusions in winter-spring. Using cell cultures, we show that part of the DMSP δS variability could be explained by distinct DMSP metabolism in sea ice microalgae. These findings advance our understanding of the sea ice sulfur cycle and metabolic adaptations of microbes in extreme environments.
海冰微生物群落会产生大量硫代谢物二甲基巯基丙酸内盐（DMSP），它是气候冷却气体二甲基硫的前体。尽管它们对极地硫循环很重要，但海冰DMSP的驱动因素和代谢途径仍不确定。在此，我们报告了海冰DMSP硫同位素组成（S/³⁴S比率，δ³⁴S）的首次测量结果。罗斯海和威德尔海冰芯中的δ³⁴S值显示出季节间以及冰层间（从+10.6‰至+23.6‰）存在显著差异。我们讨论了所观测到的最极端δ³⁴S值可能如何与冬春季节孤立盐水包裹体极端理化条件下独特的DMSP循环相关。通过细胞培养，我们表明海冰微藻中不同的DMSP代谢可以解释部分DMSP的δ³⁴S变异性。这些发现增进了我们对海冰硫循环以及极端环境中微生物代谢适应性的理解。
