Dyfamed-benthos time series observations

In 1990, a benthic component to the DYFAMED (dynamics of fluxes in the Mediterranean) program, the DYFAMED-BENTHOS survey, was established to investigate the possible coupling of benthic to pelagic processes at a permanent station in >2700 m water depth, 52 km off Nice, France. Surface sediment was first sampled at different periods of the year to assess the importance of the biological compartment (particularly metazoan meiofauna) and its relation to seasonally varying particulate matter input to the sea floor (estimated by measuring surface sediment particle size and porosity, as well as chloroplastic pigments, organic carbon, nitrogen and calcium carbonate contents). Beginning in 1993, surface sediment was sampled at an average interval of 1.4 months for over five consecutive years using multicorers. Biogeochemical techniques such as deployments of a free-vehicle benthic respirometer and a near-bottom sediment trap, along with analyses of sediment vertical profiles for dissolved oxygen, nutrients and dissolved metals in the porewater, were developed in conjunction with more extensive biological analyses to characterize the recycling of organic matter, and ultimately increase our understanding of the oceanic carbon cycle. This article provides the scientific background and motivation for the development of the on-going DYFAMED-BENTHOS survey, the general characteristics of the benthic site, as well as a detailed description of the sampling design applied from late 1990–2000.1990年，为探究法国尼斯外52公里处水深超2700米的固定站位上底栖与浮游过程的潜在耦合关系，地中海通量动力学（DYFAMED，Dynamics of Fluxes in the Mediterranean）项目增设了底栖子调查DYFAMED-BENTHOS。研究团队最初于一年中的不同时段采集表层沉积物样本，以评估生物组分（尤其后生动物小型底栖生物（metazoan meiofauna））的重要性，及其与季节性输入至海底的颗粒物质之间的关联——该关联通过测定表层沉积物的粒径、孔隙度，以及叶绿素类色素、有机碳、总氮与碳酸钙含量进行估算。1993年起，研究团队使用多管采泥器（multicorers），以平均每1.4个月的间隔连续五年多采集表层沉积物样本。研究团队开发了生物地球化学技术，包括布设自主式底栖呼吸仪（free-vehicle benthic respirometer）与近底沉积物捕集器（near-bottom sediment trap），并对沉积物垂直剖面的孔隙水（porewater）中溶解氧、营养盐与溶解金属开展分析；同时配合更全面的生物学分析，以表征有机质的再循环过程，最终加深我们对海洋碳循环的理解。本文阐述了持续推进的DYFAMED-BENTHOS调查项目的研发背景与科学动机，介绍了该底栖研究站位的基本特征，并详细说明了1990年末至2000年间所采用的采样方案。