Secondary production and priming reshape the organic matter composition in marine sediments

作者：Qingzeng Zhu, Xiuran Yin, Heidi Taubner, Jenny Wendt, Michael W. Friedrich, Marcus Elvert, Kai‐Uwe Hinrichs, Jack J. Middelburg · 发表于：Science Advances · 年份：2024 · DOI：10.1126/sciadv.adm8096 · 被引用次数：35 · 研究领域：Microbial Community Ecology and Physiology、Marine and coastal ecosystems、Methane Hydrates and Related Phenomena

Organic matter (OM) transformations in marine sediments play a crucial role in the global carbon cycle. However, secondary production and priming have been ignored in marine biogeochemistry. By incubating shelf sediments with various 13 C-labeled algal substrates for 400 days, we show that ~65% of the lipids and ~20% of the proteins were mineralized by numerically minor heterotrophic bacteria as revealed by RNA stable isotope probing. Up to 11% of carbon from the algal lipids was transformed into the biomass of secondary producers as indicated by 13 C incorporation in amino acids. This biomass turned over throughout the experiment, corresponding to dynamic microbial shifts. Algal lipid addition accelerated indigenous OM degradation by 2.5 to 6 times. This priming was driven by diverse heterotrophic bacteria and sulfur- and iron-cycling bacteria and, in turn, resulted in extra secondary production, which exceeded that stimulated by added substrates. These interactions between degradation, secondary production, and priming govern the eventual fate of OM in marine sediments.