Phytoplankton are plant-like microscopic cells so abundant that they operate on a global scale and can be seen from space. Phytoplankton fix carbon and produce oxygen. They are also the foundation of the marine food web and drive biogeochemical functions like nutrient cycling. Many phytoplankton types coexist in communities with other organisms which collectively act on global processes. Measuring the abundance and distribution of different types of phytoplankton is essential to understand their extensive ecological roles and relationships to Earth's biogeochemistry. Identifying phytoplankton community composition is key to regulating climate change because it directly influences the rate at which carbon dioxide is removed from the atmosphere and buried on the seafloor.
Today remote sensing from NASA satellites detects chlorophyll-a. Most phytoplankton contain chlorophyll-a, but many types also use other photosynthetic pigments. Different phytoplankton types contain unique ratios of these pigments. Data of chlorophyll-a count most phytoplankton together which says little about the dynamics of community compositions.
To address this gap, NASA and partners have been working for over a decade to launch the Plankton Aerosols Clouds and Ecosystems (PACE) mission. The PACE satellite will use hyperspectral resolution and multispectral polarimetry. The large range of color will detect many photosynthetic pigments. Analyzing PACE data will detect types using the known pigment rations. This advance could reveal correlations between the health and stability of marine life to the flow of carbon through ocean systems in real-time.