TONGA cruise DNA nifH sequences

The goal of the TONGA cruise is to develop a dedicated strategy involving hydrothermal plume tracers detection (3He, CH4, CO2, Mn, Fe, Si...) to 1) accurately quantify Fe (and other chemicals) input from shallow volcanoes and associated hydrothermalism (hereafter referred to as hydrothermal Fe) along the Tonga volcanic arc between 20 and 25oS for the upper mixed layer, 2) study the fate of Fe plumes in the water column at the local and regional scales, and 3) investigate the potential impact of such Fe input on planktonic communities and biogeochemical cycles in the WTSP. To achieve this goal, we propose the multidisciplinary approach described below involving hydrothermal geochemists, physical oceanographers, trace element chemists (ocean and atmosphere), biogeochemists, biologists and modelers.

本次TONGA巡航的核心目标为构建一套专项探测策略，用于检测热液羽状流示踪剂（3He、甲烷（CH4）、二氧化碳（CO2）、锰（Mn）、铁（Fe）、硅（Si）等），以达成三项研究任务：其一，精准量化汤加火山弧20°S至25°S区间内，浅层火山及相关热液活动（下文简称热液铁）向表层混合层输入的铁（及其他化学物质）通量；其二，探究局地与区域尺度下水体中铁羽状流的归趋；其三，考察此类铁输入对西热带南太平洋（Western Tropical South Pacific, WTSP）浮游生物群落及生物地球化学循环的潜在影响。为实现上述研究目标，本研究拟采用如下所述的多学科协同研究方案，联合热液地球化学家、物理海洋学家、海洋与大气领域痕量元素化学家、生物地球化学家、生物学家及数值模型研究者共同开展工作。