Sea‐ice microbial communities in the Central Arctic Ocean: Limited responses to short‐term pCO2 perturbations
Sea‐ice microbial communities in the Central Arctic Ocean: Limited responses to short‐term pCO2 perturbations
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DOI：
10.1002/lno.11690
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发表时间：
2021-01
影响因子：
4.5
通讯作者：
A. Torstensson;Andrew R. Margolin;G. Showalter;W. Smith;E. Shadwick;S. Carpenter;Francesco Bolinesi;J. Deming
中科院分区：
文献类型：
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作者：
A. Torstensson;Andrew R. Margolin;G. Showalter;W. Smith;E. Shadwick;S. Carpenter;Francesco Bolinesi;J. Deming
北冰洋比其他海洋环境更容易受到海洋酸化的影响，因为它的缓冲能力较弱，而其盐度相对较低的寒冷地表水促进了大气中二氧化碳的吸收。我们研究了北冰洋中部的海冰微生物群落如何受到碳酸盐系统变化的影响，这些变化预计是海洋酸化的结果。在2018年夏末的一系列四个实验中，我们在破冰船奥登上解决了微生物生长，溶解有机碳（DOC）和胞外聚合物（EPS）的产生，光合作用活性和细菌组合结构，因为海冰微生物群落暴露于升高的CO2分压（pCO 2）。我们在不同的营养方案下，在大约400、650、1000和2000 μatm pCO 2的单独实验中孵育了完整的底部冰芯切片和脱落的冰下藻类聚集体（主要是直链藻）10天。结果表明，海冰藻类和细菌的生长不受这些较高pCO 2水平的影响，DOC和EPS的浓度不受CO2富集导致的无机C/N平衡变化的影响。因此，这些北极海冰微生物群落似乎对短期pCO 2扰动基本不敏感。鉴于海冰碳酸盐系统的自然、季节性波动，其常驻微生物可能对pCO 2的大幅变化有足够的耐受力，因此比浮游生物群落更容易受到海洋酸化的影响，即使北极海冰的损失仍在继续，海冰微生物的生态重要性也在增加。
The Arctic Ocean is more susceptible to ocean acidification than other marine environments due to its weaker buffering capacity, while its cold surface water with relatively low salinity promotes atmospheric CO2 uptake. We studied how sea‐ice microbial communities in the central Arctic Ocean may be affected by changes in the carbonate system expected as a consequence of ocean acidification. In a series of four experiments during late summer 2018 aboard the icebreaker Oden, we addressed microbial growth, production of dissolved organic carbon (DOC) and extracellular polymeric substances (EPS), photosynthetic activity, and bacterial assemblage structure as sea‐ice microbial communities were exposed to elevated partial pressures of CO2 (pCO2). We incubated intact, bottom ice‐core sections and dislodged, under‐ice algal aggregates (dominated by Melosira arctica) in separate experiments under approximately 400, 650, 1000, and 2000 μatm pCO2 for 10 d under different nutrient regimes. The results indicate that the growth of sea‐ice algae and bacteria was unaffected by these higher pCO2 levels, and concentrations of DOC and EPS were unaffected by a shifted inorganic C/N balance, resulting from the CO2 enrichment. These central Arctic sea‐ice microbial communities thus appear to be largely insensitive to short‐term pCO2 perturbations. Given the natural, seasonally driven fluctuations in the carbonate system of sea ice, its resident microorganisms may be sufficiently tolerant of large variations in pCO2 and thus less vulnerable than pelagic communities to the impacts of ocean acidification, increasing the ecological importance of sea‐ice microorganisms even as the loss of Arctic sea ice continues.