SGER: Offshore mobilization of aged floodplain organic matter in response to Hurricane Katrina

拟议的研究旨在研究在应对卡特里娜飓风（2005年8月29日在密西西比鸟足三角洲以西登陆，风暴潮影响了大面积富含有机质的沼泽地）后，洪泛平原沉积物的再动员和离岸输送后，将老化的洪泛平原有机质（OM）吸收到近海岸和离岸沉积物微生物群落中。这种沉积物移动可能导致有机碳和氮积累速率，生物需氧量和营养再生的偏移。该项目将从布雷东和钱德尔勒海峡收集沉积物岩心，检查卡特里娜飓风过境前后沉积的近岸和近海沉积物中有机物的浓度和组成，（13 C，14 C）从卡特里娜飓风前后的沉积物中分离的磷脂，并通过描述卡特里娜飓风相关沉积物中的微生物群落，如磷脂谱和DNA-更广泛的影响结果将促进理解风暴事件对短期碳循环的随机扰动的影响。这项调查将与Miguel Goni及其同事对三角洲西部收集的样本进行的平行研究相协调。与卡特里娜飓风相关的有机物移动的综合覆盖范围沿着路易斯安那州海岸的相当长的一段将有助于有机物改造和再埋葬通量，净异养，O2需求和与有机物降解相关的CO2释放的估计。收集的样品将用作PI教授的沉积地球化学课程的教学工具，项目的执行将有助于Co-PI的专业发展。一位博士后科学家开始建立她的研究生涯。

PetschEAR-0555047The proposed research seeks to examine the uptake of aged, floodplain organic matter (OM) into near- and offshore sediment microbial communities following the remobilization and offshore delivery of floodplain deposits in response to Hurricane Katrina, which made landfall on Aug. 29, 2005 just west of the Mississippi birdsfoot delta, with a storm surge impacting a large area of OM-rich marshlands. This sediment mobilization may lead to excursions in organic carbon and nitrogen accumulation rates, biological oxygen demand, and nutrient regeneration. The project will collect sediment cores from Breton and Chandeleur Sounds, examining the concentration and composition of OM in nearshore and offshore sediments deposited before and after passage of Katrina, examining the distribution and isotopic composition (13C, 14C) of phospholipids isolated from pre- and post-Katrina sediments, and through description of the microbial communities in Katrina-associated sediments as revealed by phospholipid profiles and DNA-based community assays.Broader ImpactsResults will promote understanding of the impact of storm events on stochasticperturbations of the short-term carbon cycle. The investigation will be coordinated with parallel research pursued by Miguel Goni and colleagues on samples collected west of the delta. This combined coverage of OM mobilization associated with Katrina along a substantial length of the Louisiana coast will contribute to estimates of OM reworking and reburial fluxes, net heterotrophy, O2 demand and CO2 release linked to OM degradation.Samples collected will be employed as teaching tools in a Sedimentary Geochemistry course taught by the PI, and execution of the project will contribute to the professional development of the Co-PI, a post-doctoral scientist beginning to establish her research career.