Space station image captures a red tide ciliate bloom at high spectral and spatial resolution.

Abstract

Significance: Many different types of plankton bloom in the coastal ocean. Some produce harmful toxins, whereas others are considered important contributors to primary production and ecosystem dynamics. Routine ocean color sensors can reveal a dense bloom or “red tide” from space but cannot differentiate types of plankton. The Hyperspectral Imager for the Coastal Ocean on the International Space Station allowed for new “hyperspectral” approaches to identify pigments and assess biophysical forcing associated with different blooms. Consistent with field and molecular observations, imagery revealed dense surface patches of Mesodinium rubrum , a ciliate that uses the chloroplasts from its cryptophyte algal prey to photosynthesize. For the first time, to our knowledge, the distribution and abundance were mapped based on the unique yellow fluorescence properties of its signature pigment phycoerythrin.