S. Pillay, Dr A. J. Smit, Dr Deborah Robertson-Andersson. Presented at the Physiology Society of Southern Africa (PSSA) Conference 2015.

1. S. Pillay1;3, Dr. A. J. Smit2, Dr D. Robertson-Andersson1;3
1UKZN
2UWC
3MACE Lab

2. Introduction

3. Main Aim
The aim of this study was to investigate the level and extent of N
pollution to the south coast of KZN

4. Objectives
The specific objectives were:
 (1) To determine if each estuary chosen for this study is eutrophic and
comparisons made with the current known health status
 (2) To determine the effect of season on nitrogen pollution in rocky
shores during the closed and open phase of the estuary
 (3) To determine if the level of nitrogen pollution changes with
increasing distance away from the estuary.

5. Hypotheses
It was hypothesised that :
 (1) There is a difference in N pollution among the three
sites (Hibberdene, Margate and Port Edward).
 (2) Rocky shore habitats are supplemented by
nutrients from estuarine sources

6. Study design
Choosing estuaries

7. Health state of estuary Description
Excellent Estuaries with high water quality, level of habitat
integrity are high, high diversity and high provision of
goods and services.
Good Estuaries with most of the core estuarine habitat and
estuarine support habitats still present, good water
quality, diversity of habitats and species and estuarine
processes in place.
Fair Estuaries with core estuarine habitat intact, some
estuarine support habitats, impacted water quality and
some loss of diversity and key estuarine process in
place.
Poor Estuaries with impacted core estuarine habitat.
Substantially reduced or no estuarine support habitats,
polluted water, substantial loss of diversity and/or
abundance and key estuarine processes impaired.
Highly degraded Estuaries which have had major impacts on core
estuarine habitats through infilling, canalisation and
pollution, substantially reduced or no estuarine support
habitats and major loss of key estuarine processes.
Table 1. Ranking of esturine state based on functionng and health of the system (adapted from Forbes & Demetriades
(2008))
Mhlungwa
(Hibberdene)
Kongweni
(Margate)
Mtamvuna
(Port Edward)

8. Study sites
Figure 1. Map of sites chosen for study
HibberdeneHibberdene
(Mhlungwa Estuary)
Margate
(Kongweni Estuary with WWTP)
Port Edward (Umtamvuna Estuary)

9. Hibberdene
(Mhlungwa Estuary)
Margate
(Kongweni Estuary with WWTP)
Port Edward (Umtamvuna Estuary)

10. Sampling
Mouth:
POM
DIN
δ15N (POM)
Chl a
100 m
200 m
1000 m
2000 m
δ15N of
Macroalgae
Figure 2. sampling plan for each site
600 m

11. Nutrient analysis
 Filtered samples were analysed for nitrate and
phosphate using SKALAR SAN ++ nutrient analyser
POM
 Filtrate collected on pre-combusted GFF filters were
used for POM
 Isotope analysis

12. Macroalgae
 Jania intermedia and Hypnea spicifera
www.mpcer.nau.eduTaken by: Shivanee Pillay

13. Statistical analyses
 Analysis of Covariance (ANCOVA).
 ANOVA

14. Results
Estuary
Figure 2 Level of nutrient pollution in each of the estuaries in Hibberdene (Mhlungwa),
Margate (Kongweni) and Port Edward (Umtamvuna)

15. Rocky Shores
Figure 5. 2 Level of nitrogen pollution distributed across stations in Hibberdene
(Mhlungwa), Margate (Kongweni) and Port Edward (Umtamvuna)

16. Overall outcomes and
recommendations
 Nitrogen pollution is evident among the sites concerned
 It is suggested that both the estuary and rocky shore
habitat be monitored to elucidate other factors not
considered here.
 The condition of sites chosen for this study clearly indicate
a need for mitigation of nutrient pollution in estuaries and
a greater need for development of WWTW along the coast
of KZN.
 A survey of the KZN coastline will give an indication of
those similarly impacted and in need of mitigation

17. Thank you

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