THE BIODIVERSITY OF PHYTOPLANKTON COMMUNITY IN SELECTED PARTS OF THE LAGOS LAGOON, NIGERIA

Ajani, G.E.

Nigerian Institute for Oceanography and Marine Research,

3, Wilmot Point, Bar- Beach, Victoria Island, Lagos, Nigeria

e-mail: olugee232000@yahoo.co.uk

ABSTRACT

The phytoplankton composition, diversity, abundance and distribution as well as surface water physic-chemical parameters of selected parts of the Lagos lagoon was investigated for seven months (March –September 2010). Phytoplankton and surface water samples were collected monthly from twelve stations and analysed at the laboratory. These were analysed air and water temperatures salinity, dissolved oxygen, pH, conductivity, turbidity and alkalinity. Phytoplankton was identified microscopically. Species diversity was calculated using standard indices. The phytoplankton was dominated by diatoms (19 species), blue –green algae ( 7 species), green algae (5 species) and the euglenoids ( 4 species). Menhinick Index  (D) and Margalef (d) Index were reltively high at stations Nichem textile and at Majidun and low in other stations. Moreso, stations Nichem textile and Majidun also showed significant variation (p < 0.05) in occurrence of diatoms between sampling stations, while stations such as Queen’s drive, Park view, Moba, Ofin, Mid lagoon, Ikate, Itedo, Oreta, Ibese and Ikorodu port showed no significant variation (p > 0.05) in occurrence of diatoms between stations. The rich ecological heritage of the Lagos lagoon is being threaten by the current state of environmental perturbations from municipal and industrial effluent, although some species were able to withstand these stressful situation. Changes in the biodiversity of these primary producers could make pollution management and environmental biomonitoring a little bit difficult because of the role played by these delicate organisms. However a deliberate environmental management  should be recommended.

Keywords: Phytoplankton, abundance, distribution, environmental perturbations, lagoon, municipal, industrial