Patterns of microbial community biomass, composition and HPLC diagnostic pigments in the Costa Rica upwelling dome

TitlePatterns of microbial community biomass, composition and HPLC diagnostic pigments in the Costa Rica upwelling dome
Publication TypeJournal Article
Year of Publication2016
AuthorsTaylor A.G, Landry MR, Freibott A., Selph K.E, Gutierrez-Rodriguez A.
JournalJournal of Plankton Research
Date Published2016/03
Type of ArticleArticle
ISBN Number0142-7873
Accession NumberWOS:000372874300002
Keywordsarabian sea; baja-california; biomass; central equatorial pacific; cytometry; eastern tropical pacific; Epifluorescence microscopy; flow; high-nutrient; HPLC pigments; iron fertilization; microbial community; pacific; plankton community; station aloha; subtropical north; temporal dynamics

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 chlorophyll a (Chl a) and the ratio of autotrophic carbon to Chl a were 24.1+/-1.5 mg Chl a m(-2) and 57.5+/-3.4, respectively. Absolute and relative contributions of picophytoplankton (similar to 60%), Synechococcus (>33%) and Prochlorococcus (17%) to phytoplankton community biomass were highest in the central dome region, while >20 mu m phytoplankton accounted for <= 10%, and diatoms, <2%, of biomass in all areas. Nonetheless, autotrophic flagellates, dominated by dinoflagellates, exceeded biomass contributions of Synechococcus at 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.

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