Hyperspectral Radiometry on Biogeochemical-Argo Floats: A Bright Perspective for Phytoplankton Diversity

Abstract

By installing biogeochemical sensors on 1,000 autonomous Argo profiling floats across the globe, the Biogeochemical (BGC)-Argo program is the only network capable of providing detailed observations of the physics, chemistry, and biology of the top 2,000 m of our ocean up to every 10 days, even in remote regions and during unfavorable conditions for manual sampling. This rapidly expanding network will yield large amounts of data that will help us understand marine ecosystems and biogeochemistry, evaluate the impact of increasing human-derived pressures on Earth’s climate, and develop science-based solutions for sustainable ocean and climate management. Officially established in 2016, the International BGC-Argo program has built its mission on five science pillars and two management needs. One of the grand science challenges, and also a primary element for improving management of all living marine resources, is observing the composition of phytoplankton communities (BGC-Argo Planning Group, 2016). These microscopic, drifting, unicellular algae use sunlight and seawater to transform the carbon dioxide exchanged between the atmosphere and the ocean into oxygen and complex organic compounds. Phytoplankton create enough energy to benefit the entire food chain, from zooplankton to top predators. Phytoplankton are so diverse that collectively they maintain a variety of biogeochemical and ecosystem functions, including carbon cycling and storage. These organisms display a wide variety of types, sizes, shapes, photosynthetic efficiencies, pigmentations, and light absorption properties. While various methods can be used to identify phytoplankton, the traditional method requires water samples taken at sea and experts using microscopes to identify species, distinguishing features such as size and shape. A newer, more high-tech method employs satellite observations of ocean color to provide information on cellular Hyperspectral Radiometry on Biogeochemical-Argo Floats: A Bright Perspective for Phytoplankton Diversity