Phytoplankton Organic Carbon and Sulfur Cycling at the Marginal Ice Edge Zone

北极浮游植物可能充当二氧化碳（CO2）的汇 也是二甲硫醚（DMS）的主要生产商。 最大效应 在浮游植物大量繁殖的边缘冰区 从五月到九月，随着冰层向北退去。 这些多产的沃茨可以覆盖 北极大陆架海，如巴伦支海，在任何一个生长 期 浮游植物的主要成分之一， 边缘冰区是Phaeocystis pouchetii， 是DMS的高产者。 该物种已知 排出高比例的新固定碳作为高分子 重量聚合物以形成殖民地。 后来，它沉入 在水华后期，当硝酸盐变成 限制。 硅藻，如海链藻（Thalassiosira gravida）可能占主导地位 在夏末的冰缘处爆发， P. pouchetii在早春开花（即角毛藻 socialis）。 溶解有机碳的不同模式 P. pouchetii与硅藻之间的形成和细胞沉降 需要纳入生产力模型， 北极大陆架地区CO2和DMS的产生和汇。 本实地和实验室研究的目的是， 与挪威科学家合作，目的是：（1） 确定P. pouchetii和 硅藻在冰缘开花， 生产，固定在细胞外的碳的比例，DMS 颗粒碳和硫的产生和沉降， 深度：（2）确定哪些是主要的环境 使用10年时间的有利于每种水华类型的变量 巴伦支海系列;（3）估计10年的时间 一系列的DMS生产和CO2吸收， 冰缘碳和硫收支的时间序列 布卢姆。 这项研究将提供第一个近似的 浮游植物的季节和年际变化 对冰缘碳硫循环的贡献 在北极大陆架地区开花。

Arctic phytoplankton may act as a sink for carbon dioxide (CO2) and a major producer of dimethylsulfide (DMS). Maximum effects are expected in the marginal ice zone where phytoplankton blooms extend from May to September as the ice recedes northwards. These productive waters can cover more than half the area of arctic shelf seas, such as the Barents Sea, in any one growth period. One of the main components of the phytoplankton at the marginal ice zone is Phaeocystis pouchetii which, in its colonial form, is a high producer of DMS. This species is known to excrete a high proportion of newly fixed carbon as high molecular weight polymers in order to form the colony. Later, it sinks in mass in the latter stages of the bloom when nitrate becomes limiting. Diatoms, such as Thalassiosira gravida, may dominate the bloom at the ice edge late in the summer and may also precede the P. pouchetii bloom in early spring (i.e. Chaetoceros socialis). The different patterns of dissolved organic carbon formation and cell sedimentation between P. pouchetii and diatoms need to be included in productivity models for an understanding of the production and sink of CO2 and DMS in arctic shelf areas. The objectives of this field and laboratory study, in collaboration with Norwegian scientists, are to: (1) to determine the quantitative differences between P. pouchetii and diatoms blooms in the ice edge with respect to primary production, proportion of carbon fixed that is extracellular, DMS production, and sedimentation of particulate carbon and sulfur to depth: (2) to determine which are the main environmental variables that favor each type of bloom using a 10-year time series from the Barents Sea; and (3) to estimate a 10-year time series of DMS production and CO2 uptake by combining the existing time series with carbon and sulfur budgets of the ice edge blooms. This research will provide a first approximation to the seasonal and interannual variability of the phytoplankton contribution to the carbon and sulfur cycle during the ice edge bloom in arctic shelf areas.