School of Life Science, Tsinghua University, Beijing 100083, PR China.
The Institute for Ocean Engineering, Tsinghua Shenzhen International Graduate School (SIGS), Tsinghua University, Shenzhen 518055, Guangdong Province, PR China.
Sci Total Environ. 2022 Apr 15;817:152891. doi: 10.1016/j.scitotenv.2021.152891. Epub 2022 Jan 4.
The occurrence of the 'black-malodorous phenomenon' in a waterbody is a clear sign of a highly eutrophic bay, the formation of which is associated with microbial sulfur and iron metabolism in the sediments. Oyster farming restoration has been widely studied as an important method for treating eutrophication and related ecological problems. However, few studies focus on the ecosystem-level consequences of oyster farming concerning microbial sulfur and iron cycles in the sediment. Here, we compared the physicochemical features and microbial functions of oyster farms with those of reference areas using the Geochip5.0 technique. Our results showed a significant reduction of acid volatile sulfide (AVS) content associated with oyster farming, thus alleviating the black-malodorous status of Shenzhen Bay in China. Oyster farming created loose and porous sedimentary structures and stimulated the oxidation of black-odorous compounds. Moreover, we observed that the introduction of oysters changed microbial biodiversity significantly based on gyrB gene structure, with typical sulfur- and iron-cycling microbes being enriched. We also demonstrated that microbial abilities involved in sulfur and iron metabolism were greatly increased in oyster farming areas compared with reference areas. Under such circumstances, some cascading processes (AVS uptake and rates of organic matter turnover) were improved, which eventually contributed to black odor reduction. From the microecological perspective, we conclude that the biodeposition of oysters was the key factor for water retention and improvement of microbial metabolism. This study suggests that biodeposition shapes the microbial functional communities in adjacent territories and presumably alleviates the black-malodorous compounds in sediments.
水体出现“黑臭现象”是水体高度富营养化的明显标志，其形成与沉积物中微生物硫和铁代谢有关。牡蛎养殖恢复已被广泛研究作为一种重要的治理富营养化及相关生态问题的方法。然而，很少有研究关注牡蛎养殖对沉积物中微生物硫和铁循环的生态系统水平的影响。在这里，我们使用 Geochip5.0 技术比较了牡蛎养殖场与对照区的理化特征和微生物功能。结果表明，牡蛎养殖显著降低了酸可挥发性硫化物（AVS）的含量，从而缓解了中国深圳湾的黑臭状况。牡蛎养殖创造了松散多孔的沉积结构，并刺激了黑臭化合物的氧化。此外，我们观察到，牡蛎的引入显著改变了微生物生物多样性，这是基于 gyrB 基因结构，富集了典型的硫和铁循环微生物。我们还表明，与对照区相比，牡蛎养殖区的硫和铁代谢相关的微生物能力有了很大的提高。在这种情况下，一些级联过程（AVS 吸收和有机质周转率）得到了改善，最终有助于减少黑臭。从微观生态的角度来看，我们得出结论，牡蛎的生物沉积是保持水分和改善微生物代谢的关键因素。本研究表明，生物沉积塑造了邻近区域的微生物功能群落，并可能减轻了沉积物中的黑臭化合物。
