厚壳贻贝(Mytilus coruscus)养殖区沉积物微生物多样性及固碳潜力研究

海洋蓝碳是海洋碳汇研究的重要领域,厘清不同蓝碳生境中沉积物有机碳组分格局是当前研究的热点之一。为更好地理解此问题,现以近海厚壳贻贝养殖区这一特殊蓝碳生境为对象,解析沉积物中的碳氮组分格局;进一步通过关联沉积物微生物群落、结合卡尔文循环和还原三羧酸循环的关键基因相对丰度分析,评估厚壳贻贝养殖区沉积物的固碳潜力。结果表明,相较于非养殖区,厚壳贻贝养殖区沉积物惰性碳的累积较大,氮组分主要以氨氮形式存在;同时养殖区高微生物量碳和微生物量氮指示了其沉积物中碳周转较快,碳氮组分特征差异明显。沉积物微生物高通量测序结果显示养殖区沉积物微生物主要以Gamma变形菌纲和Delta变形菌纲为主,且微生物类群与颗粒有机碳、惰性碳等碳组分存在明显的相关性。与惰性碳存在明显正相关关系的硫微螺菌科(Thiomicrospiraceae)丰度在养殖区沉积物中显著高于非养殖区沉积物。贻贝养殖区沉积物包含cbbL在内的6种关键功能基因,固碳潜力明显。研究结果将为进一步探究蓝碳生境的有机碳来源和微生物固碳效率提供基础依据。

MICROBIAL DIVERSITY AND THE POTENTIAL CAPABILITY FOR CARBON FIXATION IN SEDIMENTS OF MYTILUS CORUSCUS FARMING AREAS

Marine blue carbon is an important field of carbon sink research, and clarifying the compositional pattern of sediment organic carbon in different habitats is one of the current research key issues. In this content, the special habitat of the Mytilus coruscus farming area was taken as the object to analyze the carbon and nitrogen composition pattern in the sediment. The potential ability of carbon fixation in sediments was further evaluated by combining sediment microbial communities and the relative abundance of the Calvin cycle and reductive tricarboxylic acid cycle pathways. Results show that the accumulation of recalcitrant carbon in the sediments of the M. coruscus farming area was greater than that of non-aquaculture area, and the nitrogen component existed mainly in the form of ammonia nitrogen. Meanwhile, the high microbial biomass carbon and microbial biomass nitrogen indicated that the carbon turnover was faster in the sediment of M. coruscus farming area, and the difference in characteristic carbon and nitrogen-component was obvious. The results of bacterial high-throughput sequencing showed that Gammaproteobacteria and Deltaproteobacteria were the dominated taxa in the sediment composition in M. coruscus farming area. The microbial taxa were significantly correlated with carbon components such as particulate organic carbon and recalcitrant carbon. The abundance of Family Thiomicrospiraceae, which was significantly positively correlated with recalcitrant carbon, was higher in sediments of M. coruscus farming areas than that of non-aquaculture areas. Six key function genes, including cbbL, have been detected in the sediments of M. coruscus farming areas, with high carbon fixation ability. This study provided a novel perspective for further exploration of organic carbon source and microbial carbon fixation efficiency in blue carbon habitats in the future.