DIATOM AGGREGATES FROM THE OPEN-OCEAN

Diatom aggregates composed of one to many chains of Pseudonitzschia pseudodelicatissima were abundant (up to 10% of the autotrophic biomass) in high-nutrient open-ocean regions of both the equatorial Pacific and north Atlantic. The chains were connected at a central mass composed of fecal material. The morphology is consistent with viable diatoms growing on or from eroding fecal pellets.