Heterotrophic bacteria in the ocean initiate biopolymer degradation using extracellular enzymes that yield low molecular weight hydrolysis products in the environment, or by using a selfish uptake mechanism that retains the hydrolysate for the enzyme-producing cell. The mechanism used affects the availability of hydrolysis products to other bacteria, and thus also potentially the composition and activity of the community. In marine systems, these two mechanisms of substrate processing have been studied in the water column, but to date, have not been investigated in sediments. In surface sediments from an Arctic fjord of Svalbard, we investigated mechanisms of biopolymer hydrolysis using four polysaccharides and mucin, a glycoprotein. Extracellular hydrolysis of all biopolymers was rapid. Moreover, rapid degradation of mucin suggests that it may be a key substrate for benthic microbes. Although selfish uptake is common in ocean waters, only a small fraction (0.5%–2%) of microbes adhering to sediments used this mechanism. Selfish uptake was carried out primarily by Planctomycetota and Verrucomicrobiota. The overall dominance of extracellular hydrolysis in sediments, however, suggests that the bulk of biopolymer processing is carried out by a benthic community relying on the sharing of enzymatic capabilities and scavenging of public goods.

中文翻译：

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不同的参与者驱动极地海洋沿海沉积物中生物聚合物加工的不同机制


海洋中的异养细菌使用胞外酶启动生物聚合物降解，这些酶在环境中产生低分子量水解产物，或者通过使用自私吸收机制为产酶细胞保留水解产物。所使用的机制会影响其他细菌水解产物的可用性，从而也可能影响群落的组成和活性。在海洋系统中，这两种底物处理机制已在水体中进行了研究，但迄今为止尚未在沉积物中进行研究。在斯瓦尔巴群岛北极峡湾的表面沉积物中，我们研究了使用四种多糖和粘蛋白（一种糖蛋白）的生物聚合物水解机制。所有生物聚合物的细胞外水解都是快速的。此外，粘蛋白的快速降解表明它可能是底栖微生物的关键底物。尽管自私吸收在海水中很常见，但只有一小部分（0.5%–2%）附着在沉积物上的微生物使用这种机制。自私摄取主要由浮霉菌门和疣微生物门进行。然而，沉积物中细胞外水解的总体主导地位表明，大部分生物聚合物加工是由底栖群落进行的，依靠共享酶能力和清除公共物品。