Seasonality of picophytoplankton chlorophyll a and biomass in the central Cantabrian Sea, southern Bay of Biscay

Alejandra Calvo-Díaz*, Xosé Anxelu G. Morán, Luis Ángel Suárez

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

52 Scopus citations


Seasonal changes in the abundance and biomass of cyanobacteria (Synechococcus and Prochlorococcus) and picoeukaryotes were studied by flow cytometry in the upper layers of the central Cantabrian Sea continental shelf, from April 2002 to April 2006. The study area displayed the typical hydrographic conditions of temperate coastal zones. A marked seasonality of the relative contribution of prokaryotes and eukaryotes was found. While cyanobacteria were generally more abundant for most of the year (up to 2.4 105 cells mL- 1), picoeukaryotes dominated the community (up to 104 cells mL- 1) from February to May. The disappearance of Prochlorococcus from spring through summer is likely related to shifts in the prevailing current regime. The maximum total abundance of picophytoplankton was consistently found in late summer-early autumn. Mean photic-layer picoplanktonic chlorophyll a ranged from 0.06 to 0.53 μg L- 1 with a relatively high mean contribution to total values (33 ± 2% SE), showing maxima around autumn and minima in spring. Biomass (range 0.58-40.16 mg C m- 3) was generally dominated by picoeukaryotes (mean ± SE, 4.28 ± 0.27 mg C m- 3) with an average contribution of cyanobacteria of 30 ± 2%. Different seasonality of pigment and biomass values resulted in a clear temporal pattern of picophytoplanktonic carbon to chlorophyll a ratio, which ranged from 10 (winter) to 140 (summer). This study highlights the important contribution of picoplanktonic chlorophyll a and carbon biomass in this coastal ecosystem.

Original languageEnglish (US)
Pages (from-to)271-281
Number of pages11
JournalJournal of Marine Systems
Issue number1-4
StatePublished - Jul 2008
Externally publishedYes

Bibliographical note

Funding Information:
We are indebted to the captain and crew of R/V José de Rioja and to M. Maiques for chlorophyll a determinations. F. González Blázquez collaborated in the preparation of Fig. 1 . We thank two anonymous referees for constructive criticisms of an earlier version of this manuscript. A. C.-D. was a recipient of a FPI pre-doctoral fellowship from the Spanish Ministry of Education and Science. This work was supported by the Spanish research grant VARIPLACA (CICYT, REN2001-0345/MAR) and the time-series project RADIALES from the Instituto Español de Oceanografía (IEO).


  • Bay of Biscay
  • Biomass
  • Cantabrian Sea
  • Chlorophyll
  • Coastal waters
  • Phytoplankton
  • Picoplankton
  • Temporal variations

ASJC Scopus subject areas

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


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