A new class of transparent organic particles in seawater visualized by a novel fluorescence approach

A method for visualizing transparent material in seawater, described here, has led to the discovery of novel particles. The protocol is based on Alcian Blue and SYBR Gold staining of seawater samples on polycarbonate filters. While the particles detected by our method may have some overlap with previously described transparent exopolymer particles and Coomassie stained particles, these particles largely comprise a previously undetected class. We propose that the particles are detected because they cause spatially explicit inhibition of Alcian Blue quenching of SYBR Cold fluorescence of the filter. Samples collected from various locations (Ellen Browning Scripps Memorial Pier, California, the Palmer Peninsula, Antarctica, and Point Conception, California) revealed particles with abundances on the order of 10 and 10(5) 1(-1) and ranging in size from 10 to 10(5) mu m(2). The particles varied in the types of organisms attached, the internal structure and probable biological sources. Field observations and laboratory experimental manipulations suggest varied sources and mechanisms of formation. These particles are potential hot spots of organic matter, microbial diversify and interactions, and, depending on their size and sinking rates, serve as conduits for carbon export to the ocean's interior.