Ref ID : 6847
T.K. Gyedu-Ababio, J.P. Furstenberg, D. Baird, and A. Vanreusel; Nematodes as indicators of pollution: a case study from the Swartkops River system, South Africa. Hydrobiologia 397:155-169, 1999
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Nematodes from the sediments of the Swartkops estuary in Port Elizabeth, South Africa were investigated at 10 selected sites along a salinity gradient in the subtidal region at neap tide. The relation between nematode density, genera, community structure and environmental parameters including concentrations of seven heavy metals, Mn, Ti, Cr, Pb, Fe, Sn and Zn in the sediment were investigated. The nematode community structure was significantly influenced by the chlorophyll a concentration and sediment particle-size distribution. The number of genera had significant negative correlation with chlorophyll a and two heavy metals, Fe and Zn in the sediment. The habitat preferences of the genera were also assessed. A combination of the Shannon-Wiener Diversity Index (H') and the Maturity Index (MI) proved to be very useful in assessing polluted or stressed sites. The nematode communities at sites which are affected by pollution, were found to be under stress according to the density, diversity and other indices used in this study. At sites where relatively higher heavy metal concentrations occurred, variation in the nematode densities and diversity were observed. Nematode community structure at polluted sites differed significantly (p<0.05) from those at less or no polluted sites. Monhystera spp. and Theristus spp. were found to be colonisers, and thus indicator genera for polluted sediments in this study.