Stevens Joshua T E, Ray Nicholas E, Al-Haj Alia N, Fulweiler Robinson W, Chowdhury Priyanka Roy
bioRxiv. 2023 Nov 13:2023.11.13.566866. doi: 10.1101/2023.11.13.566866.
The global aquaculture industry has grown substantially, with consequences for coastal ecology and biogeochemistry. Oyster aquaculture can alter the availability of resources for microbes that live in sediments as oysters move large quantities of organic material to the sediments via filter feeding, possibly leading to changes in the structure and function of sediment microbial communities. Here, we use a chronosequence approach to investigate the impacts of oyster farming on sediment microbial communities over 7 years of aquaculture activity in a temperate coastal system. We detected shifts in bacterial composition (16S rRNA amplicon sequencing), changes in gene expression (meta-transcriptomics), and variations in sediment elemental concentrations (sediment geochemistry) across different durations of oyster farming. Our results indicate that both the structure and function of bacterial communities vary between control (no oysters) and farm sites, with an overall increase in diversity and a shift towards anoxic tolerance in farm sites. However, little to no variation was observed in either structure or function with respect to farming duration suggesting these sediment microbial communities are resilient to change. We also did not find any significant impact of farming on heavy metal accumulation in the sediments. The minimal influence of long-term oyster farming on sediment bacterial function and biogeochemical processes as observed here can bear important consequences for establishing best practices for sustainable farming in these areas.
Sediment microbial communities drive a range of important ecosystem processes such as nutrient recycling and filtration. Oysters are well-known ecological engineers, and their presence is increasing as aquaculture expands in coastal waters globally. Determining how oyster aquaculture impacts sediment microbial processes is key to understanding current and future estuarine biogeochemical processes. Here, we use a multi-omics approach to study the effect of different durations of oyster farming on the structure and function of bacteria and elemental accumulation in the farm sediments. Our results indicate an increase in the diversity of bacterial communities in the farm sites with no such increases observed for elemental concentrations. Further, these effects persist across multiple years of farming with an increase of anoxic tolerant bacteria at farm sites. The multi-omics approach used in this study can serve as a valuable tool to facilitate understanding of the environmental impacts of oyster aquaculture.
全球水产养殖业大幅增长，对沿海生态和生物地球化学产生了影响。牡蛎养殖会改变沉积物中微生物可利用的资源，因为牡蛎通过滤食将大量有机物质输送到沉积物中，这可能导致沉积物微生物群落的结构和功能发生变化。在此，我们采用年代序列方法，研究在一个温带沿海系统中，7年牡蛎养殖活动对沉积物微生物群落的影响。我们通过16S rRNA扩增子测序检测到细菌组成的变化、通过宏转录组学检测到基因表达的变化以及通过沉积物地球化学检测到不同养殖时长下沉积物元素浓度的变化。我们的结果表明，对照（无牡蛎）位点和养殖位点的细菌群落结构和功能存在差异，养殖位点的多样性总体增加，且向耐缺氧方向转变。然而，无论是结构还是功能，在养殖时长方面几乎未观察到变化，这表明这些沉积物微生物群落具有适应变化的能力。我们也未发现养殖对沉积物中重金属积累有任何显著影响。此处观察到的长期牡蛎养殖对沉积物细菌功能和生物地球化学过程的最小影响，对于确立这些地区可持续养殖的最佳实践可能具有重要意义。
沉积物微生物群落驱动一系列重要的生态系统过程，如养分循环和过滤。牡蛎是著名的生态工程师，随着全球沿海水产养殖的扩张，它们的数量在增加。确定牡蛎养殖如何影响沉积物微生物过程是理解当前和未来河口生物地球化学过程的关键。在此，我们采用多组学方法研究不同时长的牡蛎养殖对养殖沉积物中细菌结构和功能以及元素积累的影响。我们的结果表明，养殖位点细菌群落的多样性增加，而元素浓度未观察到此类增加。此外，这些影响在多年养殖过程中持续存在，养殖位点耐缺氧细菌数量增加。本研究中使用的多组学方法可作为一个有价值的工具，有助于理解牡蛎养殖对环境的影响。
