SGER: Assessing Nutrient Limitation of Phytoplankton Photosynthesis

本项目研究了一种新开发的生物光学仪器（泵和探针荧光计）的适用性，这种仪器可能能够测量海洋浮游植物的“健康”。理论上，该仪器为浮游植物光合作用的非破坏性测量提供了一种手段，而无需根据标准生物测量进行校准。如果这项技术得到成功验证，将能够通过测量光合效率来确定浮游植物的营养状况。目前的研究表明，在营养物充足的条件下，浮游植物的光合效率与温度和辐照度无关，而在营养物受限的条件下，光合效率则下降。本项目旨在通过限制硝酸盐、磷酸盐、硅酸盐和铁来控制三种不同种类的浮游植物的生长速度，在受控的实验室条件下对仪器进行全面测试。这种资料对于发展对海洋初级生产力的环境调节的定量了解是至关重要的。

This project examines the applicability of a newly developed bio- optical instrument (pump and probe fluorometer) that may be able to measure the "health" of oceanic phytoplankton. In theory, this instrument provides a means for non-destructive measurement of phytoplankton photosynthesis without recourse to calibration against standard biological measurements. The technique, if successfully proven, will be able to establish the nutrient status of phytoplankton from measurements of photosynthetic efficiency. Present studies indicate that photosynthetic efficiency of phytoplankton is independent of temperature and irradiance under nutrient replete conditions, but decreases under nutrient limitation. This project is designed to thoroughly test the instrument under controlled laboratory conditions using three different species of phytoplankton whose growth rates are controlled by limiting nitrate, phosphate, silicate, and iron. Such information is crucial to the development of a quantitative understanding of environmental regulation of primary productivity in the sea.