Sakowski Eric G, Wommack K Eric, Polson Shawn W
Department of Biological Sciences, University of Delaware, Newark, DE, 19711.
Department of Plant and Soil Sciences, University of Delaware, Newark, DE, 19711.
Mar Ecol Prog Ser. 2020 Oct 29;653:57-75. doi: 10.3354/meps13487.
The eastern oyster () is a keystone species in estuarine environments but faces threats to shell formation associated with warming temperatures and acidification. Extrapallial fluid (EF), which is responsible for shell formation, harbors diverse and abundant microbial communities. Commensal microbial communities are vital to host health and fitness, yet long-term studies investigating temporal responses of the EF microbiome and its function in oyster fitness are lacking. In this study, bacterial communities of oyster EF and the water column were characterized monthly from October 2010 to September 2011. We investigated the selection, composition, and dynamics of resident and transient community members, evaluated the impact of temperature on EF microbial communities, and examined the functional role of the EF microbiome. Oyster EF communities were significantly different from the water column and were enriched for several taxa, including the Deltaproteobacteria, Epsilonproteobacteria, and Gammaproteobacteria. Overall, 94 resident members were identified in oyster EF. These members were persistent and abundant, comprising on average 33% of EF communities. Resident EF communities formed high-temperature and low-temperature groups and were more abundant overall at colder temperatures. Oyster EF resident communities were predicted to be enriched for dissimilatory nitrate reduction, nitrogen fixation, nitrification, and sulfite reductase genes. Sulfate and nitrate reduction may have a synergistic effect on calcium carbonate precipitation and indirectly aid in shell formation. Therefore, the potential role of the oyster EF microbiome in shell formation warrants further investigation as oysters and other shellfish face the future impacts of ocean warming and acidification.
东部牡蛎（）是河口环境中的关键物种，但面临着与水温升高及酸化相关的贝壳形成威胁。负责贝壳形成的外套膜外液（EF）中存在多样且丰富的微生物群落。共生微生物群落对宿主的健康和适应性至关重要，但缺乏针对EF微生物组的时间响应及其在牡蛎适应性方面功能的长期研究。在本研究中，于2010年10月至2011年9月每月对牡蛎EF和水柱中的细菌群落进行了表征。我们调查了常驻和 transient 群落成员的选择、组成和动态，评估了温度对EF微生物群落的影响，并研究了EF微生物组的功能作用。牡蛎EF群落与水柱显著不同，且几种分类群有所富集，包括δ变形菌纲、ε变形菌纲和γ变形菌纲。总体而言，在牡蛎EF中鉴定出94个常驻成员。这些成员持续存在且数量丰富，平均占EF群落的33%。常驻EF群落形成了高温组和低温组，总体上在较冷温度下更为丰富。预计牡蛎EF常驻群落中异化硝酸盐还原、固氮、硝化和亚硫酸盐还原酶基因会有所富集。硫酸盐和硝酸盐还原可能对碳酸钙沉淀具有协同作用，并间接有助于贝壳形成。因此，随着牡蛎和其他贝类面临海洋变暖和酸化的未来影响，牡蛎EF微生物组在贝壳形成中的潜在作用值得进一步研究。
