Bio-optical characterization of phytoplankton groups


The main aim of this study was to understand the bio-optical properties of phytoplankton in the Western Iberia coast, according to size class. This was done by:

  • 1) analyzing the relationship between the spectral signals of phytoplankton (i.e. the specific absorption coefficients) and chlorophyll a concentrations;
  • 2) testing the usefulness of bio-optical models to differentiate phytoplankton size groups.

This study was carried out using data from 5 areas: Gorrigen seamount, Nazaré canyon, Aveiro, Cascais and CSA group (Figure 1).

Figure 1 – Map of the Western Iberian coast with sampling stations identified in the areas of Nazaré, Sines and Cascais/Lisbon Bay.


Some preliminar results showing the model obtained to describe the chlorophyll a concentrations and fractions of three size classes: microplankton, nanoplankton and picoplankton (Figure 2).

Figure 2 – Three component model for each phytoplankton component (3-micro; 2-nano; and 1-picoplankton), plotted against the total chlorophyll a concentration (A to D). The model obtained to represent data is also presented. The correspondent fractions of each component are also represented agains the total chl a concentration (E to H). Legend of data: green – Cascais; black – Nazaré; light blue – HABSpot(Surface); dark blue – HABSpot(DCM); magenta – Gorringe; red – CSA.


Ana Brito

Ana Brito joined the Centre of Oceanography (FCUL) in January 2010 as Post-doc Fellow. Her PhD was awarded by the Edinburgh Napier University and her work was focused on the development of biogeochemical models. Currently, her research interests are related to the evaluation of the ecological quality of aquatic systems and the assessment of phytoplankton communities through remote sensing.

Carolina Sá

Carolina Sá joined the Centre of Oceanography in 2005 and her research interests are related to biological applications of ocean color satellite data. She has participated in several cruises off the Portuguese coast, collecting and analyzing phytoplankton in-situ measurements for the validation of bio-optical algorithms.

Vanda Brotas

Vanda Brotas is Full Professor in the Department of Biology in the Faculty of Sciences of the University of Lisbon. She was the Director of the Center of Oceanography between 2004 and 2006. Currently, her research is mainly focused on phytoplankton ecology and dynamics assessed through HPLC and remote sensing.


Center of Oceanography (CO)

The Centro de Oceanografia (CO) is a multidisciplinary research unit of the national R&D system, whose main host institution is the Faculty of Sciences of the University of Lisbon (FCUL), the other host institution of this Centre being the University of Évora (UE).

The main research lines of the Centro de Oceanografia are the following: 

Faculty of Science of the University of Lisbon (FCUL)

The Faculty of Sciences of the University of Lisbon was established by decree of 19th April 1911. From its establishment until 1985, the year the Faculty was transferred to the new facilities at Campo Grande, the Faculty of Sciences was based in the building where the Polytechnic School (Escola Politécnica) used to be. Before this School, since the beginning of the 17th century, other cultural and scientific preeminent institutions were settled there.