EGB: Biogeochemical Processing of Bloom-Derived Organic Matter as a Function of Sediment Mixing Regime

环境地球化学与生物地球化学项目9807588Sun，et.这项建议汇集了一个高度跨学科的PI小组，以研究沉积物中藻类碳和氮的处理。据推测，在生物扰动、未混合和间歇性混合三种不同混合状态下的沉积物再工作将对有机质处理产生直接影响。将使用最新的沉积物地球化学技术来表征沉积物，并将在沉积物中监测一大套生物地球化学示踪剂，在其中添加双标记(13C和15N)藻类材料作为一种新的有机循环示踪剂。还将利用分子生物学技术跟踪微生物群落结构。反应物在有氧和缺氧条件下的振荡被认为是有机物降解和养分循环的关键。这些振荡可由自然事件(例如风暴)和人为影响(例如富营养化)触发。因此，这项工作的结果将对我们对沿海海洋健康的理解产生广泛的影响。这项提议是环境地球化学和生物地球化学计划的一部分。它将由海洋科学司、化学和运输系统司以及地球科学司共同资助。

ENVIRONMENTAL GEOCHEMISTRY AND BIOGEOCHEMISTRY PROGRAMABSTRACT9807588Sun, et. al.This proposal brings together a highly interdisciplinary group of PIs to study the processing of algal carbon and nitrogen in sediments. It is hypothesized that sediment reworking under three different mixing regimes - bioturbated, unmixed and episodically mixed - will have a direct effect on organic matter processing. State of the art sediment geochemical techniques will be used to characterize the sediments and a large suite of biogeochemical tracers will be monitored in sediment mesocosms to which dual labeled (13C and 15N) algal material is added as a novel tracer of organic cycling. Microbial community structure will also be followed using molecular biological techniques. Oscillation of reactants between oxic and anoxic conditions is thought to be critical for organic matter degradation and nutrient cycling. These oscillations can be triggered by natural events (storms, for example) and man made impacts (eutrophication, for example). The results of the work will therefore have broad impact on our understanding of the health of the coastal ocean.This proposal was part of the Environmental Geochemistry and Biogeochemistry program. It will be jointly funded by the Division of Ocean Sciences, Division of Chemical and Transport Systems, and the Division of Earth Sciences.