Nematode abundance in cold seep sediments of the Nordic Margins (Nyregga, Styregga, Haakon Mosby Mud Volcano)

Cold-seep environments and their associated symbiont-bearing mega faunal communities create islands of primary production for macro-and meiofauna in the otherwise monotonous and nutrient-poor deep-sea environment. To examine the spatial variation and distribution patterns of metazoan meiobenthos in different seepage-related habitats, samples were collected in two regions off Norway: several pockmarks associated with the Storegga Slide including the Nyegga pockmark area, and the active, methane-venting Haakon Mosby Mud Volcano west of the Barents Sea during the Vicking cruise aboard the RV ''PourquoiPas?'' in May-June 2006. Meiofaunal samples at control sites were sampled with a multiple corer, while the other sites were sampled with push cores operated by the ROV Victor6000.The meiofaunal samples were fixed in 4% buffered formaldehyde and washed over a 32 mm-mesh sieve. Metazoan meiofauna were extracted by density gradient centrifugation. All material was fixed with 4% buffered formalin and stained with Rose Bengal. The metazoan meiofauna was sorted out, enumerated and identified down to major taxa under the stereomicroscope. Afterwards, abundances of Nematodes were depth integrated over the top 5 cm to gain individual abundances per 10 cm**2.

冷泉（cold seep）生境及其携带有共生体的大型动物群落，在原本单调贫瘠的深海环境中，为大型底栖动物与小型底栖动物构建了孤岛式的初级生产生境。为探究不同渗流相关生境中后生动物小型底栖生物（metazoan meiobenthos）的空间变异与分布格局，研究团队于2006年5—6月搭乘"Pourquoi Pas?"号科考调查船执行Vicking航次，在挪威外海两处区域采集样本：一是与Storegga滑坡（Storegga Slide）相关的多个麻坑（pockmark）区域（含Nyegga麻坑区），二是巴伦支海西侧活跃喷溢甲烷的Haakon Mosby泥火山（Haakon Mosby Mud Volcano）。对照站位的小型底栖动物样本采用多管采样器（multiple corer）采集，其余站位则借助遥控水下机器人（ROV Victor6000）操控的推杆式柱状采样器（push cores）获取。小型底栖动物样本经4%缓冲甲醛溶液固定后，通过32毫米孔径筛网进行冲洗分选。研究人员采用密度梯度离心法（density gradient centrifugation）提取后生动物小型底栖生物。所有样本均以4%缓冲福尔马林固定，并以玫瑰红（Rose Bengal）染料染色。在体视显微镜（stereomicroscope）下，对后生动物小型底栖生物完成分拣、计数，并鉴定至主要类群（major taxa）。随后，将线虫（Nematodes）的丰度按表层0—5厘米深度进行积分，以得到每10平方厘米的个体丰度。