Primary Production in the Southern Ocean

MARRA：该研究项目是美国联合全球海洋通量研究（JGOFS）南大洋项目的一部分，旨在(1)更好地了解南大洋有机和无机碳通量，(2)确定调节这些通量的大小和变化的物理、生态和生物地球化学因素和过程，以及(3)将这些通量置于当代全球碳循环的背景下。全球海洋通量联合研究已经进行了三次成功的实地工作（北大西洋、赤道太平洋、阿拉伯海），下一个主要的实地工作将在南大洋进行。JGOFS的总体目标是量化和了解控制碳和相关生物元素随时间变化通量的过程，并预测海洋生物地球化学过程对气候变化的响应。从南大洋的大小和在那里发生的物理过程（如深水和中水的形成）来判断，南大洋对全球碳循环至关重要，但其目前的定量作用尚不确定。为了成功地实现USJGOFS的目标，需要对南大洋研究计划的所有过程巡航进行初级生产的测量。将采用三种方法：原位孵育，甲板孵育和光合作用-辐照度响应。研究区域将是罗斯海的大陆架，以及罗斯海以北的极地锋地区。对光合作用的控制也将进行研究。据推测，在大陆架上，辐照限制是控制浮游植物生产力的主要因素，而在极锋地区，铁的可用性限制了浮游植物的生长并影响了种群的大小分布。生产力数据与水文数据将构成南大洋联合气候观测系统数据库的很大一部分，海上调查人员和建模人员将利用该数据库来澄清南大洋在全球碳循环中的作用。

95-30611 MARRA This research project is part of the US Joint Global Ocean Flux Study (JGOFS) Southern Ocean Program aimed at (1) a better understanding of the fluxes of carbon, both organic and inorganic, in the Southern Ocean, (2) identifying the physical, ecological and biogeochemical factors and processes which regulate the magnitude and variability of these fluxes, and (3) placing these fluxes into the context of the contemporary global carbon cycle. The Joint Global Ocean Flux Study (JGOFS) has had three successful field efforts (North Atlantic, Equatorial Pacific, Arabian Sea), and the next major field effort will be in the Southern Ocean. The overall objectives of JGOFS are to quantify and understand processes controlling the time-varying fluxes of carbon and associated biogenic elements, and to predict the response of marine biogeochemical processes to climate change. The Southern Ocean is critical to the global carbon cycle, as judged by its size and the physical process which occur there (e.g., deep and intermediate water formation), but its present quantitative role is uncertain. In order to address the objectives of USJGOFS successfully, the measurement of primary production is required for all process cruises planned for the Southern Ocean Study. Three methods will be employed: in situ incubations, deck incubations, and the photosynthesis-irradiance response. The areas of study will be the continental shelf of the Ross Sea, and the Polar Front region to the north of the Ross Sea. The controls on photosynthesis will also be investigated. It is hypothesized that on the continental shelf, irradiance limitation is the major factor controlling phytoplankton productivity, whereas in the Polar Front region, the availability of iron limits phytoplankton growth and influences the size distribution of the populations. The productivity data in conjunction with hydrographic data, will form a large part of the Southern Ocean JGOFS database which bot h at-sea investigators and modelers will use to clarify the role of the Southern Ocean in the global carbon cycle.