Barreto Marcelle Muniz, Ziegler Maren, Venn Alexander, Tambutté Eric, Zoccola Didier, Tambutté Sylvie, Allemand Denis, Antony Chakkiath Paul, Voolstra Christian R, Aranda Manuel
Red Sea Research Center, Division of Biological and Environmental Science and Engineering (BESE), King Abdullah University of Science and Technology, Thuwal, Saudi Arabia.
Department of Animal Ecology and Systematics, Justus Liebig University Giessen, Giessen, Germany.
Front Microbiol. 2021 Nov 25;12:707674. doi: 10.3389/fmicb.2021.707674. eCollection 2021.
Ocean warming and ocean acidification (OA) are direct consequences of climate change and affect coral reefs worldwide. While the effect of ocean warming manifests itself in increased frequency and severity of coral bleaching, the effects of ocean acidification on corals are less clear. In particular, long-term effects of OA on the bacterial communities associated with corals are largely unknown. In this study, we investigated the effects of ocean acidification on the resident and active microbiome of long-term aquaria-maintained colonies by assessing 16S rRNA gene diversity on the DNA (resident community) and RNA level (active community). Coral colony fragments of were kept in aquaria for 2 years at four different CO levels ranging from current pH conditions to increased acidification scenarios (i.e., pH 7.2, 7.4, 7.8, and 8). We identified 154 bacterial families encompassing 2,047 taxa (OTUs) in the resident and 89 bacterial families including 1,659 OTUs in the active communities. Resident communities were dominated by members of Alteromonadaceae, Flavobacteriaceae, and Colwelliaceae, while active communities were dominated by families Cyclobacteriacea and Amoebophilaceae. Besides the overall differences between resident and active community composition, significant differences were seen between the control (pH 8) and the two lower pH treatments (7.2 and 7.4) in the active community, but only between pH 8 and 7.2 in the resident community. Our analyses revealed profound differences between the resident and active microbial communities, and we found that OA exerted stronger effects on the active community. Further, our results suggest that rDNA- and rRNA-based sequencing should be considered complementary tools to investigate the effects of environmental change on microbial assemblage structure and activity.
海洋变暖与海洋酸化（OA）是气候变化的直接后果，影响着全球的珊瑚礁。虽然海洋变暖的影响表现为珊瑚白化频率和严重程度的增加，但海洋酸化对珊瑚的影响尚不清楚。特别是，OA对与珊瑚相关的细菌群落的长期影响在很大程度上未知。在本研究中，我们通过评估DNA（常驻群落）和RNA水平（活跃群落）上的16S rRNA基因多样性，研究了海洋酸化对长期饲养在水族箱中的珊瑚群落常驻和活跃微生物组的影响。将珊瑚群落碎片在四种不同的CO₂水平下饲养在水族箱中2年，范围从当前的pH条件到酸化加剧的情况（即pH 7.2、7.4、7.8和8）。我们在常驻群落中鉴定出154个细菌科，包含2047个分类单元（OTU），在活跃群落中鉴定出89个细菌科，包括1659个OTU。常驻群落以交替单胞菌科、黄杆菌科和考氏菌科成员为主，而活跃群落以环杆菌科和嗜变形菌科为主。除了常驻和活跃群落组成的总体差异外，活跃群落中对照（pH 8）与两个较低pH处理（7.2和7.4）之间存在显著差异，但常驻群落中仅在pH 8和7.2之间存在差异。我们的分析揭示了常驻和活跃微生物群落之间的深刻差异，并且我们发现OA对活跃群落的影响更强。此外，我们的结果表明，基于rDNA和rRNA的测序应被视为研究环境变化对微生物组合结构和活性影响的互补工具。
