Marine Oscillatoria (Trichodesmium): Development and Use of Algorithms for Remote Sensing

振荡蓝藻（Trichodesmium）是热带和亚热带海洋浮游生物中最丰富和最活跃的固氮物种。当未来发射诸如海洋颜色扫描仪和Modus I卫星等卫星时，利用遥感可以更准确地评估水华的频率、物种分布以及对N2固定和初级生产速率的估计。木霉具有一些理想的特性，独特的光谱特征和使其处于或接近地表的气体囊泡，从而便于遥感。这项研究将在西印度群岛巴巴多斯的一个实地项目中使用机载光谱仪绘制光谱特征和海洋颜色。当光谱仪在飞越中操作时，将收集有关trichodesium密度以及N2固定（乙炔还原）和初级生产速率的地面真实数据。这一信息将用于开发计算方法，以测量木霉的分布以及C和N2的固定速率。除了实地研究之外，还将对LANDSAT、CZCS和载人航天器上的现有图像进行搜索，以确定是否有任何图像是在文献报道的花期拍摄的。这些图像将被处理，以确定量化花的最佳模式。这项研究的结果将与全球海洋通量（GOFS）计划直接相关。负责大部分海洋生物生产的微观植物含有吸收阳光的色素，就像它们的陆地同类一样。长期以来，这些色素一直被用来通过对给定水体中叶绿素的直接化学分析来量化海洋浮游植物。最近，浮游植物的分布可以根据它们赋予海水的颜色来远程测量，这一发现为大规模分析海洋生物生产提供了令人兴奋的机会。卡彭特博士和他的同事们试图通过开发光学方法来确定一种被称为Trichodesmium的独特热带微生物的空间范围，从而扩展远程生物传感的使用。这种生物的分布不仅对热带地区的养分循环和生物生产力具有重要意义，而且区分表层海水中不同种类的漂浮生物的能力也是未来研究的一个重要领域。

The cyanobacterium Oscillatoria (Trichodesmium) is the most abundant and active N2 fixing species in the plankton of tropical and subtropical seas. The frequency of blooms, distribution of the species and the estimates of rate of N2 fixation and primary production could be assessed more accurately by use of remote sensing when future satellites such as the ocean color scanner and Modus I satellites are launched. Trichodesmium has some ideal properties, a unique spectral signature and gas vesicles which bring it at or near the surface, thus facilitating remote sensing. This study will use an airborne spectrometer to map the spectral signature and ocean color in a field program at Barbados, West Indies. Ground truth data will be collected on density of Trichodesmium as well as rate of N2 fixation (acetylene reduction) and primary production while the spectrometer is operated in overflights. This information will be used in developing algorithms for the measurements of Trichodesmium distributions and rates of C and N2 fixation. In addition to the field studies, a search of existing images from the LANDSAT, CZCS, and manned spacecraft will be made to determine whether any images were taken during literature reported blooms. These images will be processed to determine the best modes of quantifying blooms. Results from this research will be directly relevant to the Global Ocean Flux (GOFS) program. The microscopic plants that are responsible for most of the ocean's biological production contain pigments for absorbing sunlight just as their terrestrial counterparts do. These pigments have long been used to quantify marine phytoplankton through direct chemical analysis of the chlorophyll present in a given body of water. Recently, the discovery that phytoplankton distributions can be measured remotely based on the color they impart to the water has opened up exciting opportunities for the large scale analysis of marine biological production. Dr. Carpenter and his co-workers seek to extend the use of remote biological sensing by developing optical methods for determining the spatial extent of a unique type of tropical microorganism known as Trichodesmium. Not only is the distribution of this organism of importance to the nutrient cycling and biological productivity of tropical areas, but the ability to differentiate among the different groups of floating organism in surface ocean water is an important area for future research.