Calcification and Photosynthesis Measurements for the JGOFS Equatorial Pacific Study

该项目将在JGOFS在赤道太平洋的一次巡航中测量通过钙化和光合作用过程的碳吸收率。方解石对赤道东太平洋沉积物的压倒性贡献早已被认识到（总沉积物质量的70-90%是方解石，不到1%是有机物）。此外，这些方解石中有一半是由球石类浮游植物的钙化板产生的，这些浮游植物被称为球石。利用关于赤道太平洋地区积累速率的已发表数据和关于最终埋藏的生物固定方解石比例的保守假设，可以认为，钙化至少与热带太平洋东部的新产量相等。就每年最终埋藏的碳而言，方解石主导了碳通量，而大多数有机物质在水柱内被重新氧化为二氧化碳（CO2）。这个项目将记录表面钙化信号的大小以及标准的光合作用测量。将进行钙化和光合作用的模拟原位测量。这些数据将与沉积物圈闭数据进行比较，作为沉积物圈闭引起的累积速率的交叉检验；在赤道太平洋这样的地区，以其巨大的洋流切变而闻名，这种验证是必不可少的。这些数据也将代表赤道太平洋表面钙化的第一次直接测量，对生物学家和地质学家都将有重大的兴趣和用途。

This project will measure the rates of carbon uptake through the process of calcification and photosynthesis during one of the JGOFS cruises in the equatorial Pacific. The overwhelming contribution of calcite to the sediments of the eastern equatorial Pacific has long been realized (70-90% of the total sediment mass is calcite, and less than 1% is organic). Moreover, half of this calcite is produced from the calcified plates of coccolithophorid phytoplankters which are called coccoliths. Using published data on accumulation rates in the equatorial pacific region and conservative assumptions about the ratio of biologically fixed calcite which is ultimately buried, it can be argued that calcification is at least of equal magnitude to new production in the eastern tropical Pacific. In terms of the carbon which is ultimately buried on a yearly time scale, calcite dominated the carbon flux while most of the organic material is re-oxidized to carbon dioxide (CO2) within the water column. This project will document the magnitude of the surface calcification signal along with the standard photosynthesis measurements. Simulated-in-situ measurements will be performed of both calcification and photosynthesis. The data will be compared with the sediment trap data as a cross-check of the sediment- trap-derived accumulation rates; in a region such as the equatorial Pacific, which is known for its large current shears, this verification is essential. The data will also represent some of the first direct measurements of surface calcification in the equatorial Pacific and will be of significant interest and use to both biologists and geologists.