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

蓝藻振荡藻(Trichodesum)是热带和亚热带海域浮游生物中含量最丰富、活性最高的固氮菌。当未来的卫星，如海洋颜色扫描仪和MODUS I卫星发射时，利用遥感可以更准确地评估水华的频率、物种的分布以及氮气固定和初级生产力的估计。毛霉具有一些理想的性质，独特的光谱特征和气泡将其带到表面或接近表面，从而促进遥感。这项研究将在西印度群岛巴巴多斯的一个野外项目中使用机载光谱仪绘制光谱特征和海洋颜色的地图。当光谱仪在飞越时运行时，将收集关于毛霉菌密度以及氮气固定率(乙炔还原)和初级生产的地面真实数据。这些信息将被用于开发测量毛霉菌分布以及C和N固定速率的算法。除了实地研究，还将对陆地卫星、CZCS和载人航天器的现有图像进行搜索，以确定是否在文献报道的水华期间拍摄了任何图像。这些图像将被处理，以确定量化水华的最佳模式。这项研究的结果将与全球海洋通量(GOFS)计划直接相关。负责海洋大部分生物生产的微型植物含有吸收阳光的色素，就像陆地上的植物一样。长期以来，这些色素一直被用来通过对给定水体中存在的叶绿素进行直接化学分析来量化海洋浮游植物。最近，根据浮游植物赋予水的颜色可以远程测量浮游植物分布的发现，为海洋生物生产的大规模分析打开了令人兴奋的机会。卡彭特博士和他的同事试图通过开发光学方法来确定一种独特的热带微生物--毛霉菌--的空间范围，从而扩大遥感生物传感的应用范围。这种生物的分布不仅对热带地区的营养循环和生物生产力具有重要意义，而且区分表层海洋中不同种类的浮动生物的能力也是未来研究的重要领域。

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.