The invasive kelp Undaria pinnatifida has spread from northeastern Asia to temperate coastal environments worldwide, with profound effects on colonized ecosystems. In this work, we analyzed the effect of exudates from U. pinnatifida on the chemical and microbial properties of seawater from a semi-enclosed gulf from Atlantic Patagonia. Exudates of U. pinnatifida, consisting mainly of carbohydrates, were released at a rate of 1.6 ± 0.8 mg C g^-1 algae day^-1, affecting the quality and optical properties of seawater in experimental incubations. Parallel factor analysis based on excitation-emission matrices collected from exudates revealed the presence of two humic-like and one non-humic fluorescent components. Exudate release stimulated microbial growth and polysaccharide degrading activity in seawater. After a 7-day incubation of fresh seawater with the exudates, changes in microbial community structure were analyzed by large-scale 16S rRNA gene amplicon sequencing. Copiotrophic and fermentative genera such as Spirochaeta (Spirochaetes) and Propionigenium (Fusobacteria) increased in the incubations with algal exudates. Genomic potential prediction revealed that the selected bacterial community could have higher ribosome content - an indicator of the potential for reaching higher metabolic rates - and genes for the degradation of complex organic compounds such as polysaccharides and other carbohydrates present in the exudates. Nutrient addition triggered the emergence of other microbial populations with different ecophysiological niches: unclassified Flavobacteriales, unclassified bacteria related to the recently described Phylum Kiritimatiellaeota, as well as potential pathogens such as Vibrio (Gammaproteobacteria) and Arcobacter (Epsilonproteobacteria), suggesting potential synergistic effects between invasive macroalgae and human activities.

中文翻译：

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裙带藻的分泌物引发了大西洋巴塔哥尼亚海岸的海水化学和微生物群落的变化

入侵海带裙带菜（Undaria pinnatifida）已从东北亚扩散到全球温带沿海环境，对殖民生态系统产生了深远影响。在这项工作中，我们分析了裙带菌的分泌物对大西洋巴塔哥尼亚半封闭海湾海水的化学和微生物特性的影响。pinnatifida的分泌物主要由碳水化合物组成，在第^-1天的藻类中释放的速率为1.6±0.8 mg C g ^-1会影响实验培养中海水的质量和光学性质。基于从渗出物中收集的激发-发射矩阵的平行因子分析显示，存在两种类腐殖质和一种非腐殖质荧光成分。渗出液的释放刺激了海水中微生物的生长和多糖降解活性。在淡水与渗出液一起温育7天后，通过大规模16S rRNA基因扩增子测序分析了微生物群落结构的变化。Copiotrophic和发酵属如螺旋体（螺旋体）和Propionigenium与藻类渗出液一起培养时，（细菌）含量增加。基因组潜力的预测表明，选定的细菌群落可能具有更高的核糖体含量（潜在的达到更高代谢率的指标）以及降解复杂有机化合物（如渗出物中存在的多糖和其他碳水化合物）的基因。营养添加引发了其他具有不同生态生理生态位的微生物种群的出现：未分类的黄杆菌，与最近描述的疫霉菌相关的未分类细菌，以及潜在的病原体，如弧菌（弧菌）和阿科杆菌 （Epsilonproteobacteria），表明侵入性大藻类和人类活动之间可能存在协同作用。