Ecophysiology of Phototrophic Carbon Allocation and Partitioning in Marine Microbial Mats

[9415985] Paerl以往对微生物地垫群落碳(C)动态的研究涉及地垫内外碳的量化。虽然这些研究增加了对海洋微生物垫集体碳通量的认识，但它们没有考虑到垫是由生理和进化上不同的成分组成的，包括细菌、蓝藻和真核微藻。这项研究将追求下一个合乎逻辑的步骤，即辨别微生物垫群落的各个组成部分对C预算的贡献。本研究的显著特点是使用机械/功能方法来确定底栖微生物垫的主要生物和控制关键过程的生态生理因素。主要研究目标包括：1)阐明席群落结构和功能的生态生理过程；2)揭示微生物席群落相互作用的控制机制；3)确定物种和功能群演替。具体来说，研究将利用显微镜和高效液相色谱方法记录光养和重氮养生物的身份（分类群）和丰度（常备存量）的季节变化。利用14C、O2微电极、显微放射自显影技术和原位生长速率评价碳的固定和分配，通过一系列控制垫操作实验评估调节碳固定、分配和群落演替的主要生态生理因子（光、养分、空气暴露等）。

9415985 Paerl Previous research on carbon (C) dynamics of microbial mat communities has involved the quantification of C in and out of the mats. While these studies have increased the knowledge of the collective C fluxes of marine microbial mats, they have failed to take into account that mats are composed of physiologically and evolutionary distinct constituents including bacteria, cyanobacteria and eukaryotic microallgae. This research will pursue the next logical step which is to discern the contributions to the C budget of microbial mats by the individual components of the mat community. The distinguishing feature of this research is the use of a mechanistic/functional approach for identifying the principal organisms and ecophysiological factors controlling the key processes in benthic microbial mats. Principal research objectives include: 1) elucidating the ecophysiological processes responsible for mat community structure and function, 2) revealing mechanisms controlling microbial mat consortial interactions, and 3) identifying species and functional group succession. Specifically the research will document seasonal changes in the identity (taxonomic groups) and abundance (standing stock) of mat phototrophs and diazotrophs using microscopy and HPLC methods. C fixation and allocation will be evaluated using 14C, O2 microelectrodes, microautoradiography and in situ growth rates, The primary ecophysiological factors (light, nutrients, sub aerial exposure, etc.) that regulate C fixation, allocation and community succession will be assessed in a series of controlled mat manipulation experiments.