国家级大连刺参原种场核心区生态环境质量和微生物群落结构周年变化及其相关性分析

Annual changes in the ecological environment and microbial community structure and their correlation analyses in the core area of Dalian national sea cucumber stock field of China

关键词:  刺参  原种场核心区  生态环境质量  微生物群落结构周年变化  相关性分析

Key words:  Apostichopus japonicus  Core area of the natural farm  Ecological environmental quality  Annual changes in microbial community structure  Correlation analysis

摘要:

水产原种是良种培育的种质基础和保护生物多样性的核心，为全面掌握我国首家国家级刺参(Apostichopus japonicus)原种场核心保种区状况，本研究于2022年7月至2023年5月对该核心保种区的水环境、沉积物环境进行了周年检测，同时利用高通量测序方法分析了海水和沉积物微生物群落结构周年变化，进一步完成生态环境因子与微生物群落结构相关性分析。结果显示，海水水质良好，除春季活性磷酸盐，夏、秋、冬季铅元素和秋季镍元素含量符合Ⅱ类水质标准外，其他水质指标均符合Ⅰ类水质标准，保种区水体属于贫营养级；沉积物中除了秋季铬元素含量未达到Ⅰ类沉积物标准外，其他全部指标均符合Ⅰ类沉积物标准，表明保种区生态环境保护良好。对海水和沉积物四季微生物群落结构分析结果显示，核心区水体共获得3 796个OTUs，4个季节水体中的Shannon指数在5.90±0.04~6.84±0.01之间，秋季最高，夏季最低；沉积物中共获得4 151个OTUs，四个季节沉积物的Shannon指数在6.06±1.44~7.88±0.22之间，夏季最高，春季最低。PcoA分析显示，水体和沉积物在四季的菌群结构存在差异，且水体的菌群结构受季节影响变化相对于沉积物而言更为显著。对不同季节的水体和沉积物菌群LEfSe分析结果显示，在不同季节的水体和沉积物样品中分别筛选到73和66个显著差异菌群(P<0.05)，其中冬季沉积物中的代表性差异菌群包含弧菌科(Vibrionaceae)、冷单胞菌科(Psychromonadaceae)，需要警惕冬季弧菌对刺参健康的潜在威胁。环境因子与菌群结构的相关性分析结果表明，温度、pH、盐度是影响水体菌群结构的主要环境因子，有机碳、硫化物、重金属(铜、铅)是影响沉积物菌群结构的主要环境因子。上述研究结果为评估保种核心区生态环境、解析其风险因子和影响因素提供支撑，为我国刺参原种的高效保种提供科学依据。

Abstract:

Aquatic stock is the basis of cultivation of good strains and the core of biodiversity conservation. To comprehensively grasp of the core Breed Conservation area of China's first national sea cucumber native species farm, this study conducted an annual survey of the water body and sediment environment of the core breed conservation area from July 2022 to May 2023. Simultaneously, the annual change in microbial community structure in seawater and sediment was analyzed using high-throughput sequencing, and the correlation between ecological environment quality and microbial community structure was further completed. The results showed that the water quality of seawater was good, except for the reactive phosphate content in spring and the lead content in summer, autumn, and winter, which reached the water quality standard of ClassⅡand the heavy metal nickel, which met the water quality standard of ClassⅡin autumn. All other water quality indices met the water quality standard of ClassⅠ and the water body of the Breed Conservation area belongs to the poor trophic level. In the sediments, except for the chromium content in autumn which did not reach the standard of ClassⅠ, all other indices met the standard of ClassⅠ, indicating that the ecological environment of the core area is good. The results of microbial community structure analysis of seawater and sediments in four seasons showed that 3 796 OTUs were obtained in the water body of the core area and the Shannon index of the water body in the four seasons ranged from 5.90±0.04 to 6.84±0.01, with the highest in autumn and the lowest in summer; 4 151 OTUs were obtained in the sediment, and the Shannon index of the sediment in the four seasons was between 6.06±1.44 and 7.88±0.22, with the highest in summer and the lowest in spring. PcoA showed that the microbial community structure of the water body and sediments differed in the four seasons and the microbial community structure of the water body varied more by seasonal influences than that of sediments. The results of LEfSe analyses of water and sediment flora in different seasons showed that 73 and 66 significantly different bacteria were screened in water and sediment samples in different seasons, respectively (P<0.05), among which the representative bacteria in the winter sediment contained Vibrionaceae and Psychromonadaceae, which highlights the potential threat of vibrio to the health of sea cucumber in winter. The correlation analysis between environmental factors and microbial community structure showed that temperature, pH, and salinity were the major environmental factors affecting the microbial community structure in the water body, whereas organic carbon, sulfide, heavy metal copper, and lead were the chief environmental factors affecting the microbial community structure in the sediments. These results provide support for assessing the ecological environment of the core area for Breed Conservation, analyzing its risk factors and influencing factors, and providing scientific basis for the efficient preservation of the native sea cucumber in China.