Cell counts exhibiting 'Selfish' uptake in the Western North Atlantic, in Danish coastal seawater, and abyssopelagic waters off the eastern coast of Japan under varying hydrostatic pressures, 2023-2024

Heterotrophic bacteria and archaea (here: microbes) are critical drivers of the ocean’s biogeochemical cycles, active throughout the depth of the ocean. Their capabilities and limitations help determine the rates and locations at which carbon and nutrients are regenerated, as well as the extent to which organic matter is preserved (Hedges 1992). In the deep ocean, at bathy- and abyssopelagic depths (ca. 1000-6000m), these communities are dependent upon the sinking flux of particulate organic matter (POM) from the surface ocean (Bergauer et al. 2018). This dependence means that heterotrophic microbial communities must produce the extracellular enzymes required to solubilize and hydrolyze high molecular weight (HMW) POM to sizes substrates suitable for cellular uptake. A recent global-scale investigation of deep-sea microbes in fact found that the genetic potential for exported (extracellular) enzymes among bacteria in deep waters was far greater than for communities in surface or mesopelagic waters (Zhao et al. 2020). We have new evidence that a substantial fraction of bacteria in bottom water from the North Atlantic Ocean use a specialized set of extracellular enzymes to rapidly take up HMW polysaccharides (Giljan et al. 2022), a substrate processing mechanism that would not be detected with the low molecular weight substrates used in most prior studies of microbial activity in the deep ocean (Nagata et al. 2010). Through our collaboration with the Danish Center for Hadal Research, we were able to use pressurization systems and in situ specialized equipment to investigate the effects of pressures characteristic of bathy- and abyssopelagic depths on microbial communities and their extracellular enzymes in the open North Atlantic Ocean, in Danish Coastal Seawater, and abyssopelagic waters off the Eastern Coast of Japan. Here we present, in collaboration with colleagues from the Max Planck Institute for Marine Microbiology, the detection and quantification of microbial cells exhibiting selfish uptake behavior of fluorescently-labeled HMW polysaccharides. This dataset includes sample collection metadata, environmental variables, experimental variables, the number of cells detected exhibiting 'selfish' uptake, and total cellular abundance.异养细菌与古菌（本文统称微生物（microbes））是海洋生物地球化学循环的关键驱动因子，广泛活跃于全球海洋各深度层。它们的代谢能力与功能限制，决定了碳与营养盐的再生速率与发生位点，同时影响有机质的保存程度（Hedges 1992）。在深海的半深海带（bathypelagic）与深渊带（abyssopelagic）（约1000~6000米），这类微生物群落依赖表层海洋沉降的颗粒有机质（particulate organic matter, POM）通量（Bergauer et al. 2018）。这种营养依赖关系意味着异养微生物群落必须合成胞外酶，以溶解并水解高分子量（high molecular weight, HMW）POM，将其降解为适合细胞摄取的底物粒径。近期一项针对深海微生物的全球尺度研究发现，深海水体中细菌的分泌型（胞外）酶遗传潜力远高于表层或中层海水群落（Zhao et al. 2020）。本研究有新证据表明，北大西洋底层水体中有相当比例的细菌会通过一套特化的胞外酶系统，快速摄取高分子量多糖（Giljan et al. 2022），而这种底物加工机制，无法通过绝大多数既往深海微生物活性研究中所采用的低分子量底物检测出来（Nagata et al. 2010）。 本研究与丹麦深渊研究中心（Danish Center for Hadal Research）合作，借助加压培养系统与原位专用实验设备，探究了半深海带与深渊带典型压力条件对北大西洋开阔海域、丹麦沿岸海水以及日本东海岸外深渊带水域微生物群落及其胞外酶的影响。 本文与马克斯·普朗克海洋微生物研究所（Max Planck Institute for Marine Microbiology）的合作者共同报道了，对表现出荧光标记高分子量多糖自私摄取（selfish uptake）行为的微生物细胞的检测与定量结果。本数据集包含样品采集元数据（metadata）、环境变量、实验变量、检测到的表现出“自私”摄取行为的细胞数量，以及总细胞丰度。