29-Oct-2019 1700

Modley, Lee-Ann Sade (PhD)
Lee-Ann Sade Modley was born in Johannesburg in 1988 and matriculated from Sir
John Adamson High School in 2006. She obtained a BSc degree majoring in
Human Physiology and Zoology, followed by an Honours degree in Zoology from
the University of Johannesburg in 2011. In 2014, she obtained an MSc degree in
Environmental Management, also from the same institution. Ms Modley is currently
employed as a lecturer in the Department of Geography, Environmental
Management and Energy studies at the University of Johannesburg.
The aim of this doctoral thesis was to assess and compare aspects related to the
biotic integrity of three rivers that supply the highly polluted, hyper-eutrophic
Roodeplaat Dam. The research was done using a multi-indicator approach which
included an assessment of macroinvertebrate assemblages, fish health as well as
water quality and sediment analyses. The results of this study provides a
comprehensive contribution to better understand the complex suite of
physiochemical and biological factors impacting on water quality and in situ fish
health in the Roodeplaat catchment area. It further provides useful insight on the
bioaccumulated levels of the bio-toxin analogues microcystin-LR, -YR, and -RR in
the hepatic tissues of two indicator fish species. The study also highlights seasonal
variations in abiotic components and the associated biological responses at
different trophic levels. This research has resulted in a publication in an
international peer-reviewed journal with a second paper currently under review.
Supervisor: Prof JC van Dyk
Co-supervisor: Prof A Oldewage
Co-supervisor: Prof IT Rampedi
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