Open AccessCyanobacteria abundance and its relationship to water quality in the Mid-Cross River floodplain, Nigeria
Author(s) -
Okechukwu Idumah Okogwu,
Onwu Clement Alex
Publication year - 2013
Publication title -
revista de biología tropical
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.305
H-Index - 38
eISSN - 2215-2075
pISSN - 0034-7744
DOI - 10.15517/rbt.v57i1-2.11288
Subject(s) - cyanobacteria , aphanizomenon , abundance (ecology) , anabaena , eutrophication , floodplain , environmental science , water quality , microcystis , oscillatoria , environmental chemistry , ecology , biology , nutrient , chemistry , bacteria , genetics
The physicochemical variables and cyanobacteria of Mid-Cross River, Nigeria, were studied in six stations between March 2005 and August 2006 to determine the relationship between water quality and cyanobacteria abundance. Canonical Correspondence Analysis (CCA) showed that biological oxygen demand (BOD), dissolved oxygen, pH, water velocity, width and depth were important environmental factors that influenced cyanobacteria abundance. Trace metals, phosphate and nitrate increased significantly from values of previous studies indicating increased eutrophication of the river but were weakly correlated with cyanobacteria abundance and could be scarcely regarded as regulating factors. A higher cyanobacteria abundance was recorded during the wet season in most of the sampled stations. The dominant cyanobacteria included Microcystis aeruginosa, Aphanizomenon flos-aquae, Oscillatoria limnetica and Anabaena spiroides. The toxins produced by these species could degrade water quality. The factors favouring cyanobacteria abundance were identified as increased pH, width and depth. Increase in cyanobacteria abundance was associated with reduction in dissolved oxygen and increase in BOD values.