Obidos lagoon; located about 100 km north Lisbon, on the west coast of Portugal (30° 25'N; 9° 12'W)

Fauna abundance per unit area of the bed; Zooplankton growth rates; Sediment grain size parameters; Dissolved metal concentrations in the water column; Nitrate concentration parameters in the water column; Nitrite concentration parameters in the water column; Phosphate concentration parameters in the water column; Silicate concentration parameters in the water column; Sediment water content, porosity and surface area; Zooplankton taxonomy-related abundance per unit volume of the water column; Zoobenthos taxonomic abundance; Zooplankton non taxonomy-related abundance per unit volume of the water column; Zoobenthos taxonomy-related counts; Phytoplankton generic abundance in water bodies; Dissolved trace metalloid and inorganic selenium concentrations in water bodies; Zooplankton egg hatch proportion; Zoobenthos generic abundance; Phytoplankton taxonomic abundance in water bodies

Plankton nets; discrete water samplers; rock dredges

The Obidos lagoon has a surface area of about 7 sq.km. The depth varies between 1 and 6 metres. From August 1984 to May 1986, water and planktonic measurements were taken once a month, at 5 sampling points. In February and March 1984, 57 samples were taken for the granulometric study and spatial distribution of sediments and 57 for the macrofauna study. The temporal evolution of macrofauna were undertaken at 7 sampling stations, during 27 months (October 1984 to December 1986). The results have shown a productive system with an annual mean concentration of phytoplankton cells over 6 million cells/litre. Fish eggs were more abundant than larvae in the upper part of the lagoon. Granulometry changes, gradually, from sand at the entrance to mud at the upper part. More than 80 per cent of the bottom is mud. This lagoon showed a high tendency to eutrophication (high phytoplankton and nitrogen concentrations).

Rodrigues, A.M. and Dauvin, J.C. (1985) Crustaces Amphipodes des sediments meubles subtidaux des lagunes d'Albufeira et Obidos (Portugal). Peracarides (Amphipodes, Cumaces et Mysidaces) de la zone cotiere de la lagune d'Obidos. Ciencia Biologica, Ecol. Syst., 5: 251-267., ; Duarte, M.F., Caldeira, M.Z. and Henriques, M.F. (1990) Estudo comparativo de dois sistemas costeiros da Lagoa de Obidos e Lagoa de Albufeira. Resultados fisico-quimicos. Actas 2er Conferencia Nacional sobre a qualidade do Ambiente. Ed. F. Santana, M.C.R. Santos, M.H. Costa and D. Pereira Vol. 2: P47-P57. Lisboa. 4-6 Abril., ; Duarte, A.P. (1990) Comparacao da componente ictioplanctonica capturada em 3 sistemas costeiros: Lagoa de Albufeira, Lagoa de Obidos e 'Ria' de Alvor. Actas 2er Conferencia Nacional da Qualidade do Ambiente., Ed. F. Santana, M.C.R. Santos, M.H. Costa and D. Pereira Vol. 1: A69-A81. Lisboa. 4-6 Abril., ; Quintino, V.M.S. (1991) Estudo comparativo da estrutura e cinetica de comunidades de macrofauna bentonica de dois sistemas lagunares da costa oeste de Portugal: Obidos e Albufeira. DEII 11/91, Publicacao LNETI: 333pp + Anexos.,

National Institute of Engineering and Industrial Technology, Lisbon, Department of Industrial Impact Studies
Estrada do Paço do Lumiar, 22
Lisboa

1649-038
Portugal