Collaborative Research: Bacterial Production Uncoupled from Primary Production: Implications for DOM Fluxes in the Southern Ocean (JGOFS)

这个研究项目是美国联合全球海洋通量研究（JGOFS）南大洋计划的一部分，目的是：(1)更好地了解南大洋有机和无机碳通量，(2)确定调节这些通量的大小和变化的物理、生态和生物地球化学因素和过程，以及(3)将这些通量置于当代全球碳循环的背景下。作为JGOFS南大洋过程研究的一部分，本研究将调查细菌在有机物转化中的作用和定量重要性。研究人员假设，南大洋极端的季节和空间变化导致细菌和初级生产者之间通过溶解的有机物库介导的短暂解耦。研究的主要目标将是核心测量（细菌丰度、生物量和产量）的全面时空覆盖。这将允许对细菌消耗的初级产品的比例进行综合定量评估。同样重要的是研究控制细菌处理初级产品的速率和时间框架的机制。这对于补充核心度量和解决这些问题至关重要。具体地说，细菌总数将与含核细胞和呼吸细胞的计数相补充，以确定细菌组合的活性部分。与其他研究人员合作进行的孵化实验将检查DOM不稳定性和细菌生长量的变化。该项目将对南大洋中碳流的主要途径——微生物循环——的可变性提供定量和机制上的了解。

95-31977 Kirchman This research project is part of the US Joint Global Ocean Flux Study (JGOFS) Southern Ocean Program aimed at (1) a better understanding of the fluxes of carbon, both organic and inorganic, in the Southern Ocean, (2) identifying the physical, ecological and biogeochemical factors and processes which regulate the magnitude and variability of these fluxes, and (3) placing these fluxes into the context of the contemporary global carbon cycle. This research will investigate the role and quantitative importance of bacteria in the transformation of organic matter as part of the JGOFS Southern Ocean Process Study. Researchers hypothesize that extreme seasonal and spatial variation in the Southern Ocean leads to transient uncoupling between bacteria and primary producers as mediated through the dissolved organic matter pool. The principal goal of the research will be comprehensive spatial and temporal coverage of core measurements (bacterial abundance, biomass, and production). This will allow an integrated quantitative assessment of the fraction of primary production consumed by bacteria. Equally important is the study of the mechanisms controlling the rate and time frame in which primary production is processed by bacteria. This is critical to complement the core measurements and address these issues. Specifically, total bacteria counts will be complemented with counts of nucleoid-containing cells and respiring cells to determine the fraction of the bacterial assemblage that is active. Incubation experiments in collaboration with other researchers will examine variation in DOM lability and the growth yield of bacteria. This project will provide a quantitative and mechanistic understanding of variability in a major pathway of carbon flow, the microbial loop, in the Southern Ocean.