Biogeochemical comparison of Spartina alterniflora and Avicennia germinans soils, Barataria Bay, LA wetlands, June 2013

We compared several key biogeochemical processes in soils dominated by Spartina alterniflora and Avicennia germinans. We sampled four sites in Barataraia Bay, Louisiana in June 2013 that had distinct patches of both species. Two of these sites were oiled following the 2010 Deepwater Horizon oil spill, and the remaining two sites were unoiled. We collected four 5-cm deep cores from each vegetation type at each marsh for a total of 32 soil cores. For each core we quantified the following biogeochemical process rates: nitrification potential, greenhouse gas (CO2, CH4, N2O) production, and iron reduction. We also measured microbial abundances (ammonia-oxidizing bacteria and archaea, and methane-oxidizing bacteria) and a suite of soil properties (soil organic matter, sand content, water content, organic carbon, total nitrogen, total phosphorus, pH, extractable NO3-N, NH4-N, and PO4-P, and total Fe).本研究针对以互花米草（Spartina alterniflora）和白骨壤（Avicennia germinans）为优势植被的土壤中的关键生物地球化学过程开展对比分析。于2013年6月在路易斯安那州巴拉塔里亚湾（Barataria Bay）选取4处同时分布有两种植物独立斑块的采样点，其中2处曾受2010年深水地平线（Deepwater Horizon）原油泄漏事件污染，剩余2处未受油污影响。每个潮滩的每种植被类型下均采集4份5 cm深的土壤岩芯，总计获取32份土壤岩芯样本。针对每份岩芯，我们定量测定了以下生物地球化学过程速率：潜在硝化速率、温室气体（CO₂、CH₄、N₂O）产生速率以及铁还原速率；同时测定了微生物丰度（氨氧化细菌、氨氧化古菌及甲烷氧化细菌），并检测了一系列土壤理化性质：土壤有机质、砂粒含量、含水率、有机碳、总氮、总磷、pH值、可提取态NO₃-N、NH₄-N、PO₄-P以及总Fe。