Calcification and Photosynthesis Measurements for the JGOFS Equatorial Pacific Study

该项目将测量JGOFS在赤道太平洋的一次航行中通过钙化和光合作用过程吸收碳的速率。方解石对赤道东太平洋沉积物的巨大贡献早已被认识到(总沉淀物的70%-90%是方解石，不到1%是有机的)。此外，这些方解石的一半是由浮游植物球石的钙化板产生的，这些浮游植物被称为球石。根据赤道太平洋地区已公布的堆积率数据和关于生物固定方解石最终被埋藏的比率的保守假设，可以争辩说，在东热带太平洋，钙化至少与新的产量相等。在一年的时间尺度上，最终被埋藏的碳是方解石主导的碳通量，而大多数有机物在水柱内被重新氧化为二氧化碳(CO2)。该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结果。将对钙化和光合作用进行现场模拟测量。这些数据将与沉积物捕获器数据进行比较，以核对沉积物捕捉器产生的累积速率；在赤道太平洋等以大洋流切变而闻名的区域，这种核实是必不可少的。这些数据还将代表对赤道太平洋表面钙化的一些首次直接测量，生物学家和地质学家都将对其产生重大兴趣并加以利用。

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.