Depth-related patterns in microbial community responses to complex organic matter in the western North Atlantic Ocean
Depth-related patterns in microbial community responses to complex organic matter in the western North Atlantic Ocean
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DOI：
10.5194/bg-19-5617-2022
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发表时间：
2022-12
期刊：
影响因子：
4.9
通讯作者：
Sarah A. Brown;J. Balmonte;A. Hoarfrost;S. Ghobrial;C. Arnosti
中科院分区：
文献类型：
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作者：
Sarah A. Brown;J. Balmonte;A. Hoarfrost;S. Ghobrial;C. Arnosti
抽象的。海洋细菌群落处理海洋有机碳的主要部分。这种碳转化的很大一部分发生在中上层区域，另外一部分为深海区域的细菌提供燃料。然而，这些深度的不同微生物群落降解高分子量（HMW）有机物的能力和局限性并没有得到很好的限制。在这里，我们比较了两个开放海洋站的北大西洋表层（0-200 m）、中层（200-1000 m）和深海（1000-4000 m）水域的不同微生物群落对硅藻衍生的 HMW 颗粒和溶解有机物的相同输入的响应。微生物群落组成和对 HMW 有机质输入的功能反应（通过多糖水解酶、葡萄糖苷酶和肽酶活性测量）在相距 1370 公里的监测站之间非常相似，但随着深度的变化显示出不同的模式。微生物群落组成的变化与酶活性的变化相一致：随着细菌群落组成因 HMW 有机物的添加而变化，酶活性的速率和谱增加。在上层中生态系统中，肽酶活性谱变得特别广泛，葡萄糖苷酶活性非常高，这种模式在其他深度没有看到，相反，其他深度以亮氨酸氨肽酶为主，并且总体上肽酶和葡萄糖苷酶率要低得多。多糖水解酶活性谱特别是在上层和中层中层环境中增强，而在深海水域中速率或谱的增强较少。对相同高分子量有机物的这些不同功能反应的时间和幅度随深度而变化。我们的结果强调了特定深度的停留时间对于确定到达深海的有机物的性质和数量的重要性。
Abstract. Oceanic bacterial communities process a major fraction of marine organic carbon. A substantial portion of this carbon transformation occurs in the mesopelagic zone, and a further fraction fuels bacteria in the bathypelagic zone. However, the capabilities and limitations of the diverse microbial communities at these depths to degrade high-molecular-weight (HMW) organic matter are not well constrained. Here, we compared the responses of distinct microbial communities from North Atlantic epipelagic (0–200 m), mesopelagic (200–1000 m), and bathypelagic (1000–4000 m) waters at two open-ocean stations to the same input of diatom-derived HMW particulate and dissolved organic matter. Microbial community composition and functional responses to the input of HMW organic matter – as measured by polysaccharide hydrolase, glucosidase, and peptidase activities – were very similar between the stations, which were separated by 1370 km but showed distinct patterns with depth. Changes in microbial community composition coincided with changes in enzymatic activities: as bacterial community composition changed in response to the addition of HMW organic matter, the rate and spectrum of enzymatic activities increased. In epipelagic mesocosms, the spectrum of peptidase activities became especially broad and glucosidase activities were very high, a pattern not seen at other depths, which, in contrast, were dominated by leucine aminopeptidase and had much lower peptidase and glucosidase rates in general. The spectrum of polysaccharide hydrolase activities was enhanced particularly in epipelagic and mesopelagic mesocosms, with fewer enhancements in rates or spectrum in bathypelagic waters. The timing and magnitude of these distinct functional responses to the same HMW organic matter varied with depth. Our results highlight the importance of residence times at specific depths in determining the nature and quantity of organic matter reaching the deep sea.