We evaluated, in two consecutive austral summers, the biochemical composition, sources, distribution and degradation state of particulate organic matter (POM) in surface coastal waters of Collins Bay, King George Island, Antarctica. Bulk elemental and stable isotope analyses were combined with molecular-level proxies (fatty acids and amino acids) to obtain more comprehensive evidence about POM characteristics. Two different settings were recognized. In February 2016, there was a reduced glacier melting condition and meltwater runoff due to cold weather. Marine fresh phytoplankton and ice-associated POM with the dominance of diatoms, bacteria, zooplankton and ice-associated fauna were the major components of POM. In contrast, in January 2017 under increased glacier melting and meltwater runoff due to warm weather conditions, suspended POM was constituted by marine phytoplankton, Rhodophyta macroalgae detritus and an increased terrestrial contribution. The lower degradation state of suspended POM in February 2016 than in January 2017 and the early bacterial response to the input of fresh protein-rich organic matter derived from marine phytoplankton, mainly diatoms, was supported. Our results provide evidence of the negative impact of glacier retreat and increased meltwater runoff on POM features in Collins Bay, which can be relevant to other Antarctic coastal marine ecosystems.

我们在两个连续的南方夏季评估了南极洲乔治国王岛柯林斯湾地表沿海水域中颗粒有机物（POM）的生化组成，来源，分布和降解状态。体元素和稳定同位素分析与分子水平代理结合（脂肪酸和氨基酸）以获得有关POM特性的更全面的证据。识别出两种不同的设置。2016年2月，由于寒冷天气，冰川融化条件和融水径流减少。海洋新鲜浮游植物和与冰有关的POM以硅藻，细菌，浮游动物和与冰有关的动物为主，是POM的主要成分。相比之下，由于温暖的天气条件，2017年1月冰川融化和融水径流增加，悬浮的POM由海洋浮游植物，红藻藻类碎屑和陆地贡献增加构成。2016年2月悬浮POM的降解状态低于2017年1月，并且细菌对输入来自海洋浮游植物的富含蛋白质的新鲜有机物的早期反应，主要是硅藻，得到了支持。我们的研究结果证明了冰川退缩和融水径流量增加对柯林斯湾POM特征的负面影响，这可能与其他南极沿海海洋生态系统有关。