News and ReportsNotes on the Observations of Brown Water Discolouration off the Light House Beach, Lagos, Nigeria

Investigations into the brown water discoloration of the sea off the light house beach in Lagos, Nigeria were made. The slightly alkaline marine environment experienced high surface water temperatures (>31.0°C), high total suspended solid and total dissolved solid values (80, 85mgl-1). Phosphate and nitrate values were higher (>2.52 mgl-1) during the bloom period while heavy metal values were low ( 0.02mgl-1). The causative agent Bellerochia malleus (Brightwelli) Van Heurck occurred in large numbers (> 317,680 160 cells ml -1) with Asterionella glacialis Castracane as a sub dominant species (31; PO4 > 2.81 mg l-1; NO3>2.01 mgl-1 ) or wave action which may have concentrated species at the water front. Key Words: water discoloration, green alga, marine environment, Bellerochia malleus, Asterionella glacialis, heavy metal, suspended solid, dissolved solid, Nigeria Rsum Des recherches sur les causes de la coloration brune des eaux maritimes sur la balise d\'clairage autour de l\'embarcadre de Lagos au Nigeria ont t menes. L\'environnement marin lgrement alcalin est soumis l\'action des tempratures leves (31,0°C) des eaux de surface, des grandes teneurs en matires solides dissoutes et des matires solides en suspension (80, 85mg/litre). Les teneurs des eaux en phosphate et en nitrate taient trs leves (2,52 mg/litre) au printemps tandis que les valeurs en mtaux lourds taient basses ( ???? 0,02mg/litr e). L\'algue Bellerochia malleus (Brightwelli) Van Heurck, agent causal principal d\'une telle coloration prdominait (317, 680 160 cellules/ml), tandis que Asterionella glacialis Castracane venait en second lieu ( 31 °C, PO4 >2,81 mg/litre; NO3 >2,01 mg/litre) ou l\'action des vagues qui aurait pu concentrer l\'espce dans les eaux de front. Mots-cls: coloration des eaux, algue verte, environnement marin, Bellerochia malleus, Asterionella glacialis, matires suspendues, matires dissoutes, Nigeria Discovery and Innovation Vol. 16 (3/4) 2004: 111-11