In situ characterization of phytoplankton from vertical profiles of fluorescence emission spectra

T. J. Cowles, R. A. Desiderio, S. Neuer

Research output: Contribution to journalArticlepeer-review

94 Scopus citations


Vertical profiling of the upper ocean with a laser/fiber optic fluorometer enabled the determination of fluorescence emission spectra of photosynthetic pigments over small vertical scales. Simultaneous acquisition of phycoerythrin (PE) and chlorophyll (chl) emission spectra allowed in situ differentiation between PE-containing cells (cryptomonads and cyanobacteria) and other chl-containing autotrophs. Further, fluorescence spectral peak shifts associated with different species of PE-containing cells resulted in even finer scale in situ taxonomic differentiation. We found that the phycoerythrin fluorescence emission maxima shifted from 578 nm near the surface, to 585 μm at the base of the shallow thermocline (30% light level), and to 590 nm below the thermocline at the base of the euphotic zone (1% light level). These shifts in peak emission coincided with a taxonomic change in the PE-containing cells (as determined from analysis of discrete bottle samples) from a greater proportion of Synechococcus spp. in the upper water column to a greater proportion of cryptomonads at the base of the euphotic zone. These results indicate that the composition of the phytoplankton assemblage may be assessed in situ without sample collection.

Original languageEnglish (US)
Pages (from-to)217-222
Number of pages6
JournalMarine Biology
Issue number2
StatePublished - Feb 1 1993
Externally publishedYes

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Aquatic Science
  • Ecology


Dive into the research topics of 'In situ characterization of phytoplankton from vertical profiles of fluorescence emission spectra'. Together they form a unique fingerprint.

Cite this