Macrophytes abundance in relation to eutrophication status of peri-urban impoundments in Katsina Metropolis, Nigeria

Abstract

Aquatic Macrophytes refer to a diverse group of aquatic photosynthetic organisms that are large enough to be seen with the naked eye. Their abundance and species composition are greatly influenced by eutrophication. Macrophytes occurrence and their diversity in four seasonal peri-urban water bodies; Malalau (Site A), Rafin yan wanki (Site B), Kofar durbi (Site C), and Rafin yan tifa (Site D) in Katsina metropolis was assessed along with the pollution status of the water. The taxa diversity showed the presence of 7 species of Macrophytes in Site A and D identified as; red water fern (Azolla pinnata), water hyacinth (Eichhornia crassipes), duck weed (Spirodela polyrhiza), water lettuce (Pistia stratiotes), pond weed (Aponogeton subconjugatus), blue water lily (Nymphaea lotus), and floating heart (Nymphoides thunbergiana). Only (duck weed) was found in (Site B), whereas no single Macrophyte species was recorded in Site C. The results of physico-chemical parameters showed that the respective nitrate-nitrogen in site A (10.20 ± 0.14 mg/L), and site D (9.48 ± 0.11 mg/L) where significantly higher (p ˂ 0.05) compared to site B (6.58 ± 0.13 mg/L) and site C (1.33 ± 0.09 mg/L). A similar trend was observed in phosphate level, but not significant (p ˃ 0.05). The abundance of Macrophytes appeared to be more positively correlated with nitrogen than phosphorous. The occurrence of Macrophytes and their abundance in this research was an indication of urban pollution.