Heterotrophic microbes initiate the degradation of high molecular weight organic matter using extracellular enzymes. Our understanding of differences in microbial enzymatic capabilities, especially among particle-associated taxa and in the deep ocean, is limited by a paucity of hydrolytic enzyme activity measurements. Here, we measured the activities of a broad range of hydrolytic enzymes (glucosidases, peptidases, polysaccharide hydrolases) in epipelagic to bathypelagic bulk water (nonsize-fractionated), and on particles (≥ 3 μm) along a 9800 km latitudinal transect from 30°S in the South Pacific to 59°N in the Bering Sea. Individual enzyme activities showed heterogeneous latitudinal and depth-related patterns, with varying biotic and abiotic correlates. With increasing latitude and decreasing temperature, lower laminarinase activities sharply contrasted with higher leucine aminopeptidase (leu-AMP) and chondroitin sulfate hydrolase activities in bulk water. Endopeptidases (chymotrypsins, trypsins) exhibited patchy spatial patterns, and their activities can exceed rates of the widely measured exopeptidase, leu-AMP. Compared to bulk water, particle-associated enzymatic profiles featured a greater relative importance of endopeptidases, as well as a broader spectrum of polysaccharide hydrolases in some locations, and latitudinal and depth-related trends that are likely consequences of varying particle fluxes. As water depth increased, enzymatic spectra on particles and in bulk water became narrower, and diverged more from one another. These distinct latitudinal and depth-related gradients of enzymatic activities underscore the biogeochemical consequences of emerging global patterns of microbial community structure and function, from surface to deep waters, and among particle-associated taxa.

中文翻译：

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微生物酶的巨大变化：太平洋从 30°S 到 59°N 散装水和颗粒相关酶活性的异质纬度和深度相关梯度

异养微生物使用细胞外酶启动高分子量有机物的降解。我们对微生物酶促能力差异的理解，特别是在颗粒相关分类群和深海中，受到水解酶活性测量缺乏的限制。在这里，我们测量了上层到深海大量水（未分级）和颗粒（≥ 3  μm) 沿着从南太平洋 30°S 到白令海 59°N 的 9800 公里横断面。个体酶活性显示出与纬度和深度相关的异质模式，具有不同的生物和非生物相关性。随着纬度的增加和温度的降低，在散装水中，较低的海带多糖酶活性与较高的亮氨酸氨肽酶 (leu-AMP) 和硫酸软骨素水解酶活性形成鲜明对比。内肽酶（胰凝乳蛋白酶、胰蛋白酶）表现出不规则的空间模式，它们的活性可以超过广泛测量的外肽酶 leu-AMP 的速率。与散装水相比，与颗粒相关的酶谱具有更大的相对重要性，内肽酶以及某些位置的多糖水解酶谱更广，和纬度和深度相关的趋势，这些趋势可能是不同粒子通量的结果。随着水深的增加，颗粒和散装水中的酶谱变得更窄，彼此之间的差异更大。这些不同的纬度和深度相关的酶活性梯度强调了微生物群落结构和功能的新兴全球模式的生物地球化学后果，从地表到深水，以及颗粒相关的分类群。