Alcamán-Arias María Estrella, Fuentes-Alburquenque Sebastián, Vergara-Barros Pablo, Cifuentes-Anticevic Jerónimo, Verdugo Josefa, Polz Martin, Farías Laura, Pedrós-Alió Carlos, Díez Beatriz
Department of Oceanography, Universidad de Concepcion, Concepcion 4030000, Chile.
Center for Climate and Resilience Research (CR)2, Santiago 8320000, Chile.
Microorganisms. 2021 Jan 1;9(1):88. doi: 10.3390/microorganisms9010088.
Current warming in the Western Antarctic Peninsula (WAP) has multiple effects on the marine ecosystem, modifying the trophic web and the nutrient regime. In this study, the effect of decreased surface salinity on the marine microbial community as a consequence of freshening from nearby glaciers was investigated in Chile Bay, Greenwich Island, WAP. In the summer of 2016, samples were collected from glacier ice and transects along the bay for 16S rRNA gene sequencing, while in situ dilution experiments were conducted and analyzed using 16S rRNA gene sequencing and metatranscriptomic analysis. The results reveal that certain common seawater genera, such as , and HTCC2207, responded positively to decreased salinity in both the bay transect and experiments. The relative abundance of these bacteria slightly decreased, but their functional activity was maintained and increased the over time in the dilution experiments. However, while ice bacteria, such as and , tolerated the increased salinity after mixing with seawater, their gene expression decreased considerably. We suggest that these bacterial taxa could be defined as sentinels of freshening events in the Antarctic coastal system. Furthermore, these results suggest that a significant portion of the microbial community is resilient and can adapt to disturbances, such as freshening due to the warming effect of climate change in Antarctica.
南极半岛西部当前的气候变暖对海洋生态系统产生了多种影响，改变了营养网络和营养状况。在本研究中，我们在南极半岛格林威治岛的智利湾调查了附近冰川融水导致的表层盐度降低对海洋微生物群落的影响。2016年夏季，我们从冰川冰和沿海湾的样带采集样本进行16S rRNA基因测序，同时进行原位稀释实验，并使用16S rRNA基因测序和宏转录组分析进行分析。结果表明，某些常见的海水属，如、和HTCC2207，在海湾样带和实验中对盐度降低均有积极反应。这些细菌的相对丰度略有下降，但其功能活性得以维持，并在稀释实验中随时间增加。然而，虽然冰细菌，如和，在与海水混合后能够耐受盐度增加，但其基因表达却大幅下降。我们认为，这些细菌类群可被定义为南极沿海系统淡水事件的哨兵。此外，这些结果表明，很大一部分微生物群落具有恢复力，能够适应干扰，如南极气候变化变暖效应导致的淡水化。
