Recent trends of chlorophyll-a and phytoplankton size classes in the Atlantic Ocean

AĞIRBAŞ E., Martinez-Vicente V., Brewin R. J., Racault M., Airs R., Llewellyn C.

the 20 years of AMT conference, Plymouth, United Kingdom, 23 - 25 June 2015, pp.16

  • Publication Type: Conference Paper / Summary Text
  • City: Plymouth
  • Country: United Kingdom
  • Page Numbers: pp.16
  • Recep Tayyip Erdoğan University Affiliated: Yes


Recent trends of chlorophyll-a and phytoplankton size classes in the Atlantic Ocean

Ertugrul Agirbas*,1, Victor Martinez-Vicente1, Robert J.W. Brewin1,

Marie-Fanny Racault1, Ruth Airs1 and Carole Llewellyn1, 2


*Recep Tayyip Erdogan University, Faculty of Fisheries, 53100, Rize, TURKEY


1Plymouth Marine Laboratory, Prospect Place, the Hoe, PL1 3DH, Plymouth, UK

2Swansea University, Singleton Park, SA2 8PP, Swansea, Wales, UK


We examine the temporal change in total chlorophyll concentration (TCHLa = CHLa +DvCHLa) and in phytoplankton size classes (PSC, microphytoplankton, nanophytoplankton and picophytoplankton), using group specific pigment concentrations from High Performance Liquid Chromatography (HPLC) analysis. Data were obtained from the Atlantic Meridional Transect (AMT) cruises between 2003 and 2010. Over this period, in the first optical depth, no significant changes were observed in TCHLa. This observation was also shown in ocean-colour data from satellite. Conversely, significant changes were observed in the phytoplankton size structure derived from pigment data. The microphytoplankton fraction exhibited statistically significant decrease in northern and tropical provinces whereas the nanophytoplankton fractions exhibited statistically significant increase over the time, except for in the tropical provinces and the picophytoplankton fractions significantly increased in southern provinces. We have applied a three-component model of size structure (applicable to remote sensing) to investigate inter-annual changes in model parameters.


Key words: Atlantic Meridional Transect, First optical depth, Chlorophyll, Phytoplankton Size Classes