Abstract：
The structure and function of the water microbial community can change dramatically between different rearing modes. Yet investigations into the relationships between microbial community and water quality remain obscure. We provide the first evidence that rearing modes alter bacterial community and water quality in the rearing water of the mud crab (Scylla paramamosain) larvae. The juveniles in the recirculating aquaculture system (RAS) had a higher viability than those in the water exchange system (WES). RAS had the significantly lower levels of total ammonia nitrogen (TAN), NH3, NO2--N, total nitrogen (TN), total dissolved solids (TDS), and chemical oxygen demand than those of WES. The number of significantly different amplicon sequence variants between rearing modes increased as the larvae developed. NH3, TAN, TDS, NO2--N, and TN were closely related to the late alterations in water bacterial community. Both the FAPROTAX tool and quantitative PCR analysis showed enhanced nitrogen cycling functional potential of water bacterial community of RAS. Random forest analysis identified the enriched water bacteria especially heterotrophic bacteria such as Phaeodactylibacter, Tenacibaculum, and Hydrogenophaga, which were vital in removing nitrogenous compounds via simultaneous nitrification and denitrification. Notably, RAS could save 18.5 m3 of seawater relative to WES in larviculture on the scale of 2.5 m3. Together, these data indicate that RAS could function as microbial community and water quality management strategy in the larviculture of crab.
摘要：
水微生物群落的结构和功能可以在不同的饲养模式之间发生巨大变化。然而，对微生物群落与水质之间关系的研究仍然不清楚。我们提供了第一个证据，证明饲养方式会改变泥蟹（Scyllaparamamosain）幼虫的饲养水中的细菌群落和水质。循环水产养殖系统（RAS）中的幼鱼比水交换系统（WES）中的幼鱼具有更高的生存力。RAS的总氨氮（TAN）水平明显较低，NH3,NO2--N,总氮(TN)，总溶解固体（TDS），和化学需氧量比WES。饲养模式之间显著不同的扩增子序列变体的数量随着幼虫的发育而增加。NH3,TAN,TDS,NO2--N,TN和TN与水细菌群落的后期变化密切相关。FAPROTAX工具和定量PCR分析均显示RAS水细菌群落的氮循环功能潜力增强。随机森林分析确定了富集的水细菌，特别是异养细菌，例如Phaeodactylibacter，肌腱杆菌,和Hydrogenophaga，这对于通过同步硝化和反硝化去除含氮化合物至关重要。值得注意的是,在2.5m3的规模内，RAS相对于WES可以节省18.5m3的海水。一起,这些数据表明，RAS可以在蟹的幼虫培养中发挥微生物群落和水质管理策略的作用。
