Constraining and Understanding Bacterial Biomass and Production Variability in Ocean Ecosystems

Ducklow这项工作是美国JGOFS合成和建模计划(SMP)的一部分，旨在对海洋浮游细菌介导的碳通量和转化数据进行建模和合成。在许多海洋系统中，细菌是生物量的主要成分(也许是主要成分)，实际上是水生生态系统中溶解有机碳(DOC)周转的唯一因素。此外，它们通过剧烈的生物合成和水解过程促进颗粒的形成和分解，从而影响垂直沉积速率和模式。在JGOFS期间，获得了前所未有的关于浮游细菌丰度和生产率的数据，但它尚未在海洋生物地球化学方面留下印记。20世纪80年代中期，S设计了JGOFS研究，当时细菌过程的概念模型还很粗糙，数值模型基本上还不存在。在JGOFS的十年中，这两种模型的发展都取得了进展，但大多没有经验限制的好处。另一方面，JGOFS细菌数据有一些重大缺陷：从丰度(以及最近的生物量)测量推断生物量水平可能不确定一个数量级。由同位素前体掺入率得出的碳基生产率也同样不确定。通过参与JGOFS SMP，通过用新数据改进和约束现有模型，以及通过开发新的概念和数值模型，研究人员计划实现两个主要目标：1)减少观测的不确定性，增加观测的意义；2)提高我们对细菌如何影响海洋浮游生物系统中的碳通量和生态系统功能的理解。这项研究代表了一位观察海洋微生物生态学家(Ducklow)和两位海洋生物地球化学/生态模型师(Fasham和Anderson)之间的合作努力。

DucklowThis work is a part of the Synthesis and Modelling Program (SMP) of US JGOFS aimed at modelling and synthesis of data on carbon fluxes and transformations mediated by oceanic bacterioplankton. Bacteria are a major (and perhaps the dominant) component of biomass in many ocean systems and are practically the sole agents of dissolved organic carbon (DOC) turnover in aquatic ecosystems. Further, they contribute to particle formation and breakdown through intense biosynthetic and hydrolytic processes, thus influencing vertical sedimentation rates and patterns. An unprecedented amount of data on bacterioplankton abundance and production rates was obtained during JGOFS but it has yet to make its mark in ocean biogeochemistry. At the time the JGOFS studies were designed in the mid-1980's, conceptual models of bacterial processes were crude, and numerical models were largely nonexistent. Development of both types of models has advanced in the JGOFS decade, but mostly without benefit of empirical constraints. JGOFS bacterial data, on the other hand, have some significant shortcomings: extrapolations of biomass levels from abundance (and more recently biovolume) measurements are uncertain by perhaps an order of magnitude. Carbon-based rates of production derived from isotopic precursor incorporation rates are similarly uncertain. By participating in the JGOFS SMP, by improving and constraining existing models with new data, and by developing new models, both conceptual and numerical, the investigators plan to meet two principal goals: l) reduce the uncertainties of, and add meaning to the observations; and 2) improve our understanding of how bacteria influence carbon fluxes and ecosystem functions in ocean plankton systems. This research represents a collaborative effort between an observational marine microbial ecologist (Ducklow) and two ocean biogeochemical/ecological modelers (Fasham and Anderson).