Calcite Production Rates in the Arabian Sea

小行星9311077 作为美国JGOFS计划的一部分，该项目将解决阿拉伯海相对于有机生产的钙化程度。 地质和地球化学证据表明，在这一非常多产的地区，方解石主导着碳的埋藏。 然而，在与标准光合作用测量兼容的时间尺度上，没有直接的钙化估计。 间接估计的基础上垂直变化的碱度和TCO 2表明，真光层钙化率将在0.3-0.4 gC m-2 d-1的顺序在东南季风相比，初级生产1-2 gC m-2 d-1。 根据沉积物积累率的间接估计给出了非常相似的预测。 然而，在碳埋藏方面，有机碳优先被矿化，使得区域有机碳沉积为2.65x105吨C yr-1，不到北方阿拉伯海方解石埋藏3.6x106吨C yr-1的十分之一。 这种方解石产量的间接估计需要广泛的假设，需要用经验数据进行验证。 钙化的直接同位素估计是必不可少的了解方解石的生产率的大小，在与标准的初级生产测量兼容的时间尺度上测量。 同样重要的是将钙化的估计与该计划中其他人所作的地球化学估计进行比较。 ***

9311077 Balch This project will address the magnitude of the calcification relative to the organic production in the Arabian Sea as part of the U.S. JGOFS program. Geological and geochemical evidence points to calcite dominating the burial of carbon in this very productive region. However, no direct estimates of calcification exist at time scales compatible with standard photosynthesis measurements. Indirect estimates based on vertical changes in alkalinity and TCO2 suggest that euphotic zone calcification rates will be on the order of 0.3-0.4 gC m-2d-1 during the SE monsoon as compared to primary production of 1-2 gC m-2 d-1. Indirect estimates based on sediments accumulation rates give very similar predictions. In terms of carbon burial, however, the organic carbon is preferentially remineralized such that the regional organic carbon deposition is 2.65x10 5 tonnes C yr-1, less than a tenth of the calcite burial of 3.6x10 6 tonnes C y-1 over the northern Arabian Sea. Such indirect estimates of calcite production require broad assumptions which need to be validated with empirical data. Direct isotope estimates of calcification are essential to understanding the magnitude of the production rate of calcite, measured on time scales compatible with standard primary production measurements. Equally important will be the comparison of the estimates of calcification with geochemical estimates made by others in the program. ***