Department of Environmental Chemistry, IDAEA-CSIC, Barcelona, Catalunya 08034, Spain.
Centre for Ecology and Evolution in Microbial Model Systems, EEMiS, Linnaeus University, Kalmar 35195, Sweden.
Environ Sci Technol. 2021 Jul 20;55(14):9609-9621. doi: 10.1021/acs.est.0c07262. Epub 2021 Feb 19.
Coastal seawaters receive thousands of organic pollutants. However, we have little understanding of the response of microbiomes to this pool of anthropogenic dissolved organic carbon (ADOC). In this study, coastal microbial communities were challenged with ADOC at environmentally relevant concentrations. Experiments were performed at two Mediterranean sites with different impact by pollutants and nutrients: off the Barcelona harbor ("BCN"), and at the Blanes Bay ("BL"). ADOC additions stimulated prokaryotic leucine incorporation rates at both sites, indicating the use of ADOC as growth substrate. The percentage of "membrane-compromised" cells increased with increasing ADOC, indicating concurrent toxic effects of ADOC. Metagenomic analysis of the BCN community challenged with ADOC showed a significant growth of and other gammaproteobacterial taxa belonging to the rare biosphere. Gene expression profiles showed a taxon-dependent response, with significantly enrichments of transcripts from SAR11 and in BCN and BL, respectively. Further, the relative abundance of transposon-related genes (in BCN) and transcripts (in BL) correlated with the number of differentially abundant genes (in BCN) and transcripts (in BLA), suggesting that microbial responses to pollution may be related to pre-exposure to pollutants, with transposons playing a role in adaptation to ADOC. Our results point to a taxon-specific response to low concentrations of ADOC that impact the functionality, structure and plasticity of the communities in coastal seawaters. This work contributes to address the influence of pollutants on microbiomes and their perturbation to ecosystem services and ocean health.
沿海海水会接收成千上万的有机污染物。然而，我们对微生物组对这 pool 人为溶解有机碳 (ADOC) 的响应几乎没有了解。在这项研究中，沿海微生物群落受到了环境相关浓度 ADOC 的挑战。实验在两个受污染物和养分影响不同的地中海地点进行：巴塞罗那港附近（“BCN”）和布拉内斯湾（“BL”）。ADOC 的添加刺激了两个地点的原核亮氨酸掺入率，表明 ADOC 可用作生长底物。随着 ADOC 的增加，“膜受损”细胞的百分比增加，表明 ADOC 同时具有毒性作用。用 ADOC 挑战 BCN 群落的宏基因组分析表明，属于稀有生物界的 和其他γ变形菌门分类群显著生长。基因表达谱显示出与分类群相关的响应，分别在 BCN 和 BL 中显著富集了 SAR11 和 的转录本。此外，转座子相关基因的相对丰度（在 BCN 中）和转录本（在 BL 中）与差异丰度基因的数量（在 BCN 中）和转录本（在 BLA 中）相关，表明微生物对污染的反应可能与预先暴露于污染物有关，转座子在适应 ADOC 中发挥作用。我们的研究结果表明，低浓度 ADOC 会对沿海海水中的群落功能、结构和可塑性产生特定分类群的影响。这项工作有助于解决污染物对微生物组的影响及其对生态系统服务和海洋健康的干扰。
