title: Space station image captures a red tide ciliate bloom at high spectral and spatial resolution.
abstract: Mesodinium rubrum is a globally distributed nontoxic ciliate that is known to produce intense red-colored blooms using enslaved chloroplasts from its algal prey. Although frequent enough to have been observed by Darwin, blooms of M. rubrum are notoriously difficult to quantify because M. rubrum can aggregate into massive clouds of rusty-red water in a very short time due to its high growth rates and rapid swimming behavior and can disaggregate just as quickly by vertical or horizontal dispersion. A September 2012 hyperspectral image from the Hyperspectral Imager for the Coastal Ocean sensor aboard the International Space Station captured a dense red tide of M. rubrum (10(6) cells per liter) in surface waters of western Long Island Sound. Genetic data confirmed the identity of the chloroplast as a cryptophyte that was actively photosynthesizing. Microscopy indicated extremely high abundance of its yellow fluorescing signature pigment phycoerythrin. Spectral absorption and fluorescence features were related to ancillary photosynthetic pigments unique to this organism that cannot be observed with traditional satellites. Cell abundance was estimated at a resolution of 100 m using an algorithm based on the distinctive yellow fluorescence of phycoerythrin. Future development of hyperspectral satellites will allow for better enumeration of bloom-forming coastal plankton, the associated physical mechanisms, and contributions to marine productivity.
authors.affiliation: Department of Marine Sciences, University of Connecticut, Groton, CT 06340; heidi.dierssen@uconn.edu.
authors.forename: Heidi
authors.initials: H
authors.lastname: Dierssen
authors.affiliation: Department of Marine Sciences, University of Connecticut, Groton, CT 06340;
authors.forename: George B
authors.initials: GB
authors.lastname: McManus
authors.affiliation: Department of Marine Sciences, University of Connecticut, Groton, CT 06340;
authors.forename: Adam
authors.initials: A
authors.lastname: Chlus
authors.affiliation: Department of Marine Sciences, University of Connecticut, Groton, CT 06340; CAS Key Laboratory of Tropical Marine Bio-resources and Ecology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China;
authors.forename: Dajun
authors.initials: D
authors.lastname: Qiu
authors.affiliation: Remote Sensing Division, Naval Research Laboratory, Washington, DC 20375.
authors.forename: Bo-Cai
authors.initials: BC
authors.lastname: Gao
authors.affiliation: Department of Marine Sciences, University of Connecticut, Groton, CT 06340;
authors.forename: Senjie
authors.initials: S
authors.lastname: Lin
mesh_terms: D000465:Algorithms; D002736:Chloroplasts / Q000378:metabolism; D003116:Color; D004275:DNA, Ribosomal / Q000378:metabolism; D004141:Dinoflagellida; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods*; D057097:Harmful Algal Bloom; D009792:Oceans and Seas; D010788:Photosynthesis; D010799:Phycoerythrin / Q000737:chemistry; D063809:Satellite Imagery; D018531:Spacecraft
chemical_list: D004275:DNA, Ribosomal; D010799:Phycoerythrin
keywords: Mesodinium ciliate; hyperspectral; ocean color; red tide; remote sensing