Patterns of microbial community biomass, composition and HPLC diagnostic pigments in the Costa Rica upwelling dome.
We investigated biomass, size-structure, composition, depth distributions and spatial variability of the phytoplankton community in the Costa Rica Dome (CRD) in June-July 2010. Euphotic zone profiles were sampled daily during Lagrangian experiments in and out of the dome region, and the community was analyzed using a combination of digital epifluorescence microscopy, flow cytometry and HPLC pigments. The mean depth-integrated biomass of phytoplankton ranged 2-fold, from 1089 to 1858 mg C m-2(mean ± SE = 1378 ± 112 mg C m-2), among 4 water parcels tracked for 4 days. Corresponding mean (±SE) integrated values for total chlorophylla(Chla) and the ratio of autotrophic carbon to Chlawere 24.1 ± 1.5 mg Chlam-2and 57.5 ± 3.4, respectively. Absolute and relative contributions of picophytoplankton (∼60%),Synechococcus(>33%) andProchlorococcus(17%) to phytoplankton community biomass were highest in the central dome region, while >20 µm phytoplankton accounted for ≤10%, and diatoms <2%, of biomass in all areas. Nonetheless, autotrophic flagellates, dominated by dinoflagellates, exceeded biomass contributions ofSynechococcusat all locations. Order-of-magnitude discrepancies in the relative contributions of diatoms (overestimated) and dinoflagellates (underestimated) based on diagnostic pigments relative to microscopy highlight potential significant biases associated with making community inferences from pigments.
Scripps Institution of Oceanography , 9500 Gilman Dr., La Jolla, CA 92093-0227 , USA.
Andrew G
AG
Taylor
Scripps Institution of Oceanography , 9500 Gilman Dr., La Jolla, CA 92093-0227 , USA.
Michael R
MR
Landry
Scripps Institution of Oceanography , 9500 Gilman Dr., La Jolla, CA 92093-0227 , USA.
Alexandra
A
Freibott
Department of Oceanography , University of Hawaii At Manoa , Honolulu, HI 96822 , USA.
Karen E
KE
Selph
Station Biologique de Roscoff , Place Georges Teissier, 29682 Rosscoff Credex , France.
Andrés
A
Gutiérrez-Rodríguez
HPLC pigments; biomass; epifluorescence microscopy; flow cytometry; microbial community