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

环境地球化学和生物地球化学方案这项建议汇集了一个高度跨学科的项目研究员小组，研究沉积物中藻类碳和氮的处理。 据推测，在三种不同的混合制度-生物扰动，未混合和间歇性混合的沉积物改造-将有一个有机物处理的直接影响。 将使用最先进的沉积物地球化学技术来表征沉积物，并在沉积物中围生态系统中监测大量的生物地球化学示踪剂，其中添加双标记（13 C和15 N）藻类材料作为有机循环的新型示踪剂。 还将使用分子生物学技术跟踪微生物群落结构。 反应物在好氧和缺氧条件之间的振荡被认为是有机物降解和营养循环的关键。 这些振荡可以由自然事件（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了解沿海海洋的健康状况产生广泛的影响。 该项目将由海洋科学司、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.