Iron Distribution and Effects on Phytoplankton Growth in the Seasonal Sea Ice Zone

Peter Sedwick collected water column samples (6 depths, less than 350m) and measured dissolved iron in these samples, using specialised trace-metal clean techniques, at 9 stations along the SR3 transect between 47 deg S and 66 deg S. These are the first such data for this oceanographic sector during spring. The dissolved iron levels were generally very low (less than 0.2 nM nM) in the upper water column, particularly south of the Subantarctic Front, and surprisingly there was no evidence of significant iron inputs from melting sea ice in our study region. Ongoing work quantified various size fractions of dissolved iron as well as total acid soluble iron.In addition, Jack DiTullio collected water samples for measurements of five biogenic sulfur pools at most shallow water CTD casts. The sulfur pools measured include: dimethylsulfide (DMS), particulate and dissolved dimethylsulfoniopropionate (DMSP) and particulate and dissolved pools of dimethylsulfoxide (DMSO).Taken from the referenced paper:A shipboard-deployable, flow-injection (FI) based instrument for monitoring iron(II) in surface marine waters is described. It incorporates a miniature, low-power photoncounting head for measuring the light emitted from the iron-(II)-catalyzed chemiluminescence (CL) luminol reaction. System control, signal acquisition, and data processing are performed in a graphical programming environment. The limit of detection for iron(II) is in the range 8-12 pmol L-1(based on 3s of the blank), and the precision over the range 8-1000 pmol L-1 varies between 0.9 and 7.6% (n )4). Results from a day-night deployment during a north to-south transect of the Atlantic Ocean and a daytime transect in the Sub-Antarctic Front are presented together with ancillary temperature, salinity, and irradiance data. The generic nature of the components used to assemble the instrument make the technology readily transferable to other laboratories and the modular construction makes it easy to adapt the system for use with other CL chemistries.

彼得·塞德威克（Peter Sedwick）在南纬47°至66°之间的SR3断面上的9个站位，采用专属痕量金属洁净处理技术，采集了水深小于350米的6个深度的水柱样品，并测定了其中的溶解铁含量。这是该海洋学区域春季首次发布的此类观测数据。上层水柱（尤其是亚南极锋以南区域）的溶解铁浓度普遍极低（低于0.2 nM），且令人意外的是，本研究区域未发现海冰融化带来显著铁输入的证据。当前相关研究正在定量解析溶解铁的不同粒径组分以及总酸溶铁含量。
此外，杰克·迪蒂利奥（Jack DiTullio）在多数浅水温盐深剖面仪（CTD, Conductivity-Temperature-Depth）站位采集了水样，用于测定5种生源硫库组分。所测定的生源硫库包括：二甲基硫（dimethylsulfide, DMS）、颗粒态与溶解态二甲基巯基丙酸内盐（dimethylsulfoniopropionate, DMSP），以及二甲基亚砜（dimethylsulfoxide, DMSO）的颗粒态与溶解态组分。
本内容引自已发表的研究论文：本文介绍了一款可船载部署、基于流动注射（flow-injection, FI）技术的表层海水亚铁监测仪器。该仪器集成了微型低功耗光子计数探头，用于检测亚铁催化鲁米诺化学发光（chemiluminescence, CL）反应所释放的光信号。系统控制、信号采集与数据处理均基于图形化编程环境实现。亚铁的检出限范围为8~12 pmol·L⁻¹（以空白的3倍标准差计），在8~1000 pmol·L⁻¹范围内的精密度为0.9%~7.6%（n=4）。本研究展示了该仪器在大西洋南北向断面昼夜部署以及亚南极锋区日间断面观测的实测数据，同时附带了同步获取的温度、盐度与辐照度数据。该仪器采用通用模块化组件搭建，技术方案可便捷迁移至其他实验室，且模块化结构便于适配其他化学发光检测体系。