Nutrients Dynamics and Trophic Status in A Tropical Ocean off The Lagos Coast, Nigeria

Document Type : Original Article

Author

Department of Marine Sciences, University of Lagos, Akoka, Lagos, Nigeria

Abstract

A preliminary investigation of stoichiometric nutrient ratio and the trophic status in the neritic water off the coast of Lagos, Nigeria was conducted. Monthly water samples collected from May 2015 to April 2017 were analysed using standard methods. The nutrient molar stoichiometric ratio was assayed and analysed for the potentiality of its limitation using factomineR. Physical and chemical variables showed mild variations across bi-annual seasons. Analysis of variance on the physical variables (water temperature and rainfall) and some of the chemical variables (total suspended solids, dissolved oxygen, silica and manganese) showed statistical significance (p < 0.05). Whereas salinity, acidity, nitrate, phosphate, zinc, iron and chlorophyll a were not statistically different (p < /em> > 0.05) across the wet and dry seasons of the two-year study. The stoichiometric nutrient limitation transited from nitrate limiting in the wet season with mean N: P (35.23) to silica and phosphate limiting in the dry season with mean N: Si (8.46) and Si: P (6.73) respectively which were not in the criteria threshold. Trophic status in the study area was oligotrophic. This could be evident by the clarity of water measured by the total suspended values and oxygen availability throughout the sampled period due to the continuous mixing of the studied area.

Keywords

Egyptian Academic Journal of Biological Sciences, H. Botany
Volume 9, Issue 1
December 2018
Pages 87-99

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