Departament de Biologia Marina i Oceanografia, Institut de Ciències del Mar, CSIC, Barcelona, Catalunya, 08003, Spain.
Instituto de Oceanografía y Cambio Global, IOCAG, Universidad de Las Palmas de Gran Canaria, ULPGC, Gran Canaria, 35214, Spain.
Environ Microbiol. 2021 Jan;23(1):190-206. doi: 10.1111/1462-2920.15292. Epub 2020 Nov 3.
Different factors affect the way dissolved organic matter (DOM) is processed in the ocean water column, including environmental conditions and the functional capabilities of the communities. Recent studies have shown that bathypelagic prokaryotes are metabolically flexible, but whether this versatility translates into a higher ability to process DOM has been barely explored. Here we performed a multifactorial transplant experiment to compare the growth, activity and changes in DOM quality in surface and bathypelagic waters inoculated with either surface or bathypelagic prokaryotic communities. The effect of nutrient additions to surface waters was also explored. Despite no differences in the cell abundance of surface and deep ocean prokaryotes were observed in any of the treatments, in surface waters with nutrients the heterotrophic production of surface prokaryotes rapidly decreased. Conversely, bathypelagic communities displayed a sustained production throughout the experiment. Incubations with surface prokaryotes always led to a significant accumulation of recalcitrant compounds, which did not occur with bathypelagic prokaryotes, suggesting they have a higher ability to process DOM. These contrasting abilities could be explained by the recruitment of a comparatively larger number of opportunistic taxa within the bathypelagic assemblages, which likely resulted in a broader community capability of substrate utilization.
不同的因素会影响海洋水柱中溶解有机质（DOM）的处理方式，包括环境条件和群落的功能能力。最近的研究表明，深海原核生物在代谢上具有灵活性，但这种多功能性是否转化为更高的 DOM 处理能力还几乎没有被探索过。在这里，我们进行了一项多因素移植实验，以比较用表层或深海原核生物群落接种的表层和深海水中的生长、活性和 DOM 质量变化。还探索了向表层水中添加营养物质的效果。尽管在任何处理中都没有观察到表层和深海海洋原核生物细胞丰度的差异，但在有营养物质的表层水中，表层原核生物的异养生产力迅速下降。相反，深海群落在整个实验过程中表现出持续的生产力。与深海原核生物相比，与表层原核生物的培养总是导致难降解化合物的大量积累，这在深海原核生物中没有发生，表明它们具有更高的 DOM 处理能力。这些相反的能力可以通过在深海生物群中招募相对较多的机会主义分类群来解释，这可能导致了更广泛的社区对基质利用的能力。
