A great deal of work has been done on the ecology of the intertidal some of South African by the Zoology Department of the University of Cape Town under the direction of Professor T.A. Stephenon. As a result of this a number of valuable papers have been published dealing with the plants and animals of the zone, their ecology, lateral and vertical distribution and so on. Stephenon has, in three papers (1939, 1944,1947), dealt with general results and conclusions drawn from this survey. This work dealt entirely with the biotic between tidelevels, i.e., from the sublittoral fringe upward. it did not take into account the sublittoral, that part of the shallow coast which is perpetually submerged at all tides.

Magister Artium (Psychology) - MA(Psych) / This study is a quantitative investigation into anglers’ environmental behaviours, as associated with the human-nature relationship, within the context of sustainability and conservation psychology. Although much has been researched around pro-environmental behaviours that link to the household (such as energy use and recycling behaviours) and materialism (buying environmentally friendly products), there is comparatively little to show for variables associated with pro-environmental decision-making that relates to the protection of nature. One such environmental problem involves the disregard for environmental laws protecting marine life. The study aimed to extend this line of research by looking at certain environmental fishing behaviours in a sample of recreational False Bay anglers, and using their relationship with nature (i.e. the degree to which the self recognises an interconnectedness between humans and the natural world) to explain these behaviours. Participants were required to sign a consent form, and participated anonymously in the study, particularly due to the sensitive nature of the information they disclose. A convenience sample of 99 anglers was assessed. ANOVA yielded significant biographical differences in NR with regards to particular age, level of education and residential area groups. Logistic regression analysis indicated that Nature Relatedness had significant predictive capacity for these environmental behaviours ( = 0.061), although the Nature Relatedness subscales did not. In conclusion it was speculated that NR might not offer a deep explanation for environmental behaviours in this group, considering a weak correlation between NR and behaviour (r = -.186) and the inability of the NR subscales to predict behaviour. Further research in this area is needed to provide more conclusive results.

No description available.

Thesis (PhD) -- Stellenbosch University, 2004. / ENGLISH ABSTRACT:Heavy metals are persistent environmental contaminants whose sources of inputs into the environment are both natural and anthropogenic. The levels of heavy metals (cadmium, copper, nickel, lead and zinc) in the False Bay intertidal zone were measured in the water, sediments and invertebrate species between August 2000 and August 2001. The results of the water and sediment analyses revealed that most pollution was associated with the northern shore of the bay between Strand and Muizenberg, where the most populated and industrial catchments occur. Significant spatial variations occurred, indicating the presence of localised contamination, while seasonal variations may be related to changes in precipitation and runoff at different times of the year. The concentrations of cadmium, nickel and lead were occasionally higher than the levels recommended by the South African Water Quality Standards. The possible sources of pollution at the different sites are also discussed. The concentrations of the five metals in the different invertebrate species (Oxystele tigrina, 0. sinensis, Choromytilus meridionalis, Patella oculus, Patiriella exigua and Tetraclita serrata) also revealed significant seasonal and spatial variations, with both the soft tissues and shells accumulating heavy metals. The barnacle T serrata from Rooiels had the highest cadmium concentration (70.67 J.lg/g dry weight), which may be related to historic pollution inputs from the military activities which took place at a weapons testing site at this site between 1987 and 1994, although no evidence was found to confirm this. The periwinkle 0. tigrina from Strand had the highest copper concentration (70.25 J.lg/g) while the limpet P. oculus from the same site had the highest nickel concentration (35.75 J.lg/g). The shells of the mussel C. meridionalis from Muizenberg had the highest concentration of lead (25.75 J.lg/g). Since cadmium occurs as a constituent of phosphate fertilisers used widely in the False Bay catchments, the effects of cadmium exposure on the different species were investigated during 14-day laboratory exposures to 200 and 400 J.lg/LCdCh. The results revealed a general pattern of tissue metal increase in the exposed organisms, followed by slight reductions after decontamination in clean seawater. The viscera and kidneys of C. meridionalis accumulated most of the dissolved cadmium. The shells of the mussels also accumulated cadmium, indicating the possible use of shells as a detoxification matrix. / AFRIKAANSE OPSOMMING:Swaarmetale is persisterende omgewingskontaminante waarvan die insetbronne beide natuurlik of van menslike oorsprong kan wees. Die kontaminasievlakke van swaarmetale (kadmium, koper, nikkel, lood en sink) in die Valsbaai tussengetysone is in die water, sedimente en invertebraatspesies bepaal vanaf Augustus 2000 tot Augustus 2001. Voorlopige resultate van die water- en sedimentontledings het getoon dat die meeste besoedeling by die noordelikke oewer van die baai voorgekom het tussen Strand and Muizenberg, waar die mees digbewoonde en ge-industrialiseerde opvangsgebiede is. Betekenisvolle ruimtelike en seisoenale variasie het in die konsentrasies van swaarmetale voorgekom, met die ruimtelike variasie wat moontlik gelokaliseerde kontaminasie aandui terwyl die seisoenale variasies weer verband mag hou met veranderings in die neerslag en afloop gedurende verskillende tye van die jaar. Die konsentrasie van kadmium, nikkel en lood was somtyds hoer as die vlakke wat deur die Suid-Afrikaanse Waterkwaliteitsstandaarde voorgestel word. Die moontlike bronne van besoedeling in die verskillende areas is ook in bespreking genoem. Die konsentrasies van die vyf swaametale in die verskillende invertebraatspesies (Oxystele tigrina, 0. sinensis, Choromytilus meridionalis, Patella oculus, Patiriella exigua and Tetraclita serrata) het ook seisoenale en ruimtelike variasies vertoon, die swaarmetale het in die sagte weefsel en skulpe van die invertebrate geakkumuleer. Die hoogste gemiddelde konsentrasie van kadmium (70.67 ).lg/g droe massa) is in die heel-liggaam monsters van die eendemossel T serrata gemeet wat by Rooiels versamel is. Die vlakke mag verband hou met die oprigting en aktiwiteite van die wapentoetsingsaanleg in die opvanggebied van die Rooiels lokaliteit tussen 1987 en 1994, maar geen bewyse daarvan is gevind nie. Die tolletjie, 0. tigrina wat in die 10kaliteit by Strand versamel is het die hoogste gemiddelde konsentrasie koper gehad 70.25 pig droe massa), terwyl die klipmossel P. oculus by dieselfde versamelpunt die hoogste konsentrasie nikkel (35.75 ).lg/gdroe massa) gehad het. Eksperimentele studies is ook uitgevoer op vier invertebraat spesies wat vir 14 dae in akwaria blootgestel is aan see-water met 200 en 400 p,g/L CdCh, en daama gedekontamineer is in skoon seewater. / The NRF and the University of Stellenbosch, for funding this study.

Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: Coastal erosion is a worldwide hazard of which the consequences can only be mitigated via thorough and efficient monitoring of erosion and vulnerability to erosion. This study aimed to establish the accuracy, efficacy and efficiency of various remote sensing techniques for the detection and monitoring of coastal erosion and vulnerability occurring in False Bay, South Africa. There is a need to monitor the erosion in this area as well as to determine the most effective techniques for monitoring the erosion in False Bay and other similar environments in the future. This study provides an assessment of the usefulness of different data sources and techniques for change detection in the coastal environment. The data sources used were Landsat TM/ETM+ imagery and aerial photographs. Image differencing, tasselled cap transformations, vegetation index differencing, Boolean change detection, and post-classification change detection were all performed on the Landsat imagery. The aerial photographs were assessed using the Digital Shoreline Analysis System (DSAS) add-on for ArcGIS which determines statistical differences in the shoreline position as digitised in vector format. The results showed that while the resolution of the Landsat imagery was not sufficient to analyse erosion along the beach itself, the larger area covered by the satellite images enabled vulnerability indicators to be seen. Notably, the post-classification change detection indicated consistent increases in built-up areas, while sand dune, beach, and sand (not beach) all decreased. NDVI differencing showed consistent decreases in NDVI indicating decreasing plant health and density. The results of image differencing with both band 4 and the brightness band led to conclusions that vegetation health was decreasing while reflective surfaces such as bare sand and roads were increasing. All of these indicate an increased vulnerability to coastal erosion. The Boolean change detection method was found not to be useful in this case. Aerial photographs were studied on four focus areas: Bayview Heights, Macassar Beach, Strand, and Pringle Bay. The results showed erosion at all four areas, with Strand experiencing only erosion (no accretion) at an average of 53 cm erosion per year. Erosion at Macassar Beach and Pringle Bay was also severe, with Bayview Heights being the least severe and showing a combination of erosion and accretion. The higher resolution available on the aerial photographs was vital to view changes on the beach itself. In future studies requiring assessment of changes in the position or condition of the beach itself, aerial photographs or high resolution satellite data should be used. Studies of vulnerability extending over the entire coastal zone may make use of Landsat TM images. Post-classification change detection provides powerful change direction information and can indicate the percentage of area change from one class to another. However, image differencing and vegetation index differencing are much faster to perform and can provide information about general trends in the changes occurring. Therefore post-classification change detection might be used in areas of high and rapid change while image differencing and vegetation index differencing can be useful to cover vast areas where little change is expected. / AFRIKAANSE OPSOMMING: Kus-erosie is ‘n wêreldwye gevaar waarvan die gevolge slegs deur deeglike en doeltreffende monitering van erosie en kwesbaarheid vir erosie verminder kan word. Hierdie studie poog om die akkuraatheid, doeltreffendheid en effektiwiteit van verskillende afstandswaarneming tegnieke vas te stel vir die opsporing en monitering van kus-erosie en kwesbaarheid in Valsbaai, Suid Afrika. Daar is ‘n behoefte aan die monitering van erosie in hierdie area, sowel as om die mees doeltreffende tegnieke van die monitering hiervan in Valsbaai en ander soortgelyke omgewings in die toekoms te bepaal. Hierdie studie bied ‘n evaluering van die nut van verskillende data-bronne en tegnieke vir die opsporing van verandering in ‘n kusomgewing. Die data-bronne wat gebruik is, is Landsat TM/ETM+ beelde asook lugfoto’s. Beeld differensievorming, “tasselled cap” transformasies, plantegroei indeks differensievorming, Boolse verandering en post-klassifikasie verandering is toegepas op die Landsat beelde. Die lugfotos is ge-evalueer deur die Digitale Kuslyn Analise Stelsel (Digital Shoreline Analysis System – DSAS). DSAS is ‘n bykomstige sagteware vir ArcGIS wat statistiese verskille in gedigitaliseerde kuslyn posisie bepaal. Die resultate toon dat terwyl die resolusie van die Landsat beelde nie voldoende was om strand-erosie self te analiseer, die groter area wat deur die satellietbeelde gedek word toegelaat het om kwesbaarheid aanwysers te ontleed. Spesifiek die post-klassifikasie verandering het aangedui dat konsekwente toenames in beboude areas voorkom, terwyl afnames in sandduine, strand en sand-areas voorgekom het. NDVI differensievorming het konsekwente afnames in NDVI getoon, wat dui op afnames in die gesondheid en digtheid van plantegroei. Die resultate van die beeld differensievorming met beide Landsat Band 4 en die helderheid-band het gelei tot die gevolgtrekking dat die gesondheid van plantegroei afgeneem het, terwyl reflektiewe oppervlaktes soos oop sand en paaie aan die toeneem is. Al hierdie resultate dui op die verhoogde kwesbaarheid vir kus erosie. Die Boolse verandering metode is bevind om nie van nut te wees in hierdie geval nie. Lugfoto’s van vier fokus-areas is bestudeer: Bayview Heights, Macassar Strand, Strand en Pringlebaai. Resultate van die DSAS analise het gevind dat oorwegend erosie by al vier areas plaasvind, met Strand die enigste area wat slegs erosie (geen aanwas) ervaar teen ‘n gemiddelde koers van 0.53 m per jaar. Erosie by Macassar Strand en Pringlebaai was ook ernstig, terwyl Bayview Heights die minste erosie ervaar het, met ‘n kombinasie van erosie en aanwas. Die hoër resolusie beskikbaar deur die lugfoto’s was noodsaaklik om veranderinge in strand areas waar te neem. In toekomstige studies wat die assessering van verandering in die posisie of toestand van strande noodsaak behoort lugfotos of hoë-resolusie satellietbeeld data gebruik te word. Studies oor die kwesbaarheid van ‘n hele kusstreek kan wel gebruik maak van Landsat data. Post-klassifikasie verandering bied kragtige informasie oor die rigting van verandering en kan die persentasie van verandering van een klas na ‘n ander aandui. Beeld en NDVI differensievorming is egter veel vinniger om uit te voer en kan informasie rakende die algemene tendense in verandering lewer. Post-klassifikasie verandering kan dus gebruik word in gebiede van vinnige en beduidende verandering plaasvind, terwyl beeld en NDVI differensievorming nuttig kan wees om groot areas te dek waar min verandering verwag word.

Thesis (MScEng)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: The Strand is located within False Bay and frequently encounters large quantities of wave overtopping over the coastal defences. This results in the damage of property and infrastructure and causes streets to be flooded. Physical modelling tests were done by a consultancy firm to determine a solution by making use of a recurve structure at the back of the beach. This study is an expansion of the previous physical modelling that was done and focuses on several factors that were not tested by the consultancy firm that could have an influence on the overtopping rate and provide additional information on the recurve design. These tests were: (i) the effectiveness of the proposed recurve wall design in reducing overtopping was compared to a vertical wall; (ii) the influence that modifications to the beach profile such as the beach slope, beach width and beach level have on the overtopping rate; and (iii) the sensitivity of overtopping to changes in wave period was tested. The information gathered from these tests was used to propose a possible solution for the Strand. Numerical modelling was done with Delft3D-Wave to determine the wave height at the back of the beach using a nested grid. The waves at the Strand are depth limited and therefore very sensitive to changes in water level. By altering the beach level the model showed how the significant wave height at the back of the beach changes. First estimates of overtopping were determined using the relevant empirical calculations from the EuroTop Manual 2007 for a vertical seawall. No estimate could be made for the recurve wall since it did not fall in the valid range of the equations. From the physical modelling it was found that the overtopping reduced significantly from a vertical to a recurve seawall by a factor of about 50% depending on the wall height. All the prediction methods tested proved to be accurate in estimating the overtopping when the ratio of freeboard to significant wave height was ≤1.83. For non-breaking wave conditions the beach profiles that were gently sloped (1:50) and wide produced more overtopping than the beach profiles that were steep (1:10) and narrow. Increasing the beach level only decreased the overtopping if the water depth was shallow enough to cause the waves to break before they reached the back of the beach. Overtopping was found to increase with longer wave periods until the wave period became too long and the waves broke offshore which resulted in the overtopping decreasing. Possible solutions to overtopping were proposed based on two beach levels and the implementation of a recurve seawall. Revised crest levels for the wall were made along the length of the beach for both the 1:20 and 1:100 year water levels. / AFRIKAANSE OPSOMMING: Die Strand is in Valsbaai geleë en ervaar dikwels baie oorspoeling deur golwe bo-oor kusverdedigingswerke. Dit lei tot skade aan eiendom sowel as aan infrastruktuur en veroorsaak dat strate oorstroom. Fisiese modelleringstoetse is deur ’n konsultasiefirma gedoen om ’n oplossing te probeer vind deur van ’n teruggebuigde struktuur aan die agterkant van die strand gebruik te maak. Hierdie studie is ’n uitbreiding van die vorige fisiese modellering wat gedoen is en fokus op verskeie faktore wat nie deur die konsultasiefirma getoets is nie. Dit kan moontlik ’n invloed op die oorspoelingstempo hê en verskaf bykomende inligting oor die ontwerp van die terugbuiging. Hierdie toetse is: (i) die doeltreffendheid van die voorgestelde ontwerp van die teruggebuigde strandmuur in die vermindering van oorspoeling word vergelyk met ’n vertikale muur; (ii) die invloed wat veranderinge aan die strandprofiel soos die helling van die strand, die wydte van die strand asook die strandvlak op die oorspoelingstempo het; en (iii) die sensitiwiteit van oorspoeling op veranderinge in golfperiode is getoets. Die inligting wat uit hierdie toetse verkry is, word gebruik om ’n moontlike oplossing vir die Strand voor te stel. Numeriese modellering is met Delft3D-Wave gedoen om die golfhoogte aan die agterkant van die strand vas te stel deur van ’n genestelde ruitenet gebruik te maak. Die golwe by die Strand word deur diepte beperk en is dus baie sensitief vir veranderinge in die watervlak. Deur die strandvlakke te verander het die model getoon hoe die betekenisvolle golfhoogte aan die agterkant van die strand verander. Die eerste beramings van oorspoeling is bepaal deur van die relevante empiriese berekenings uit die EuroTop-handleiding 2007 vir ’n vertikale strandmuur gebruik te maak. Daar kon geen beraming vir die teruggebuigde muur gemaak word nie aangesien dit nie binne die geldige bereik van die vergelykings val nie. Uit die fisiese modellering is daar vasgestel dat oorspoeling noemenswaardig met ’n gemiddeld van ongeveer 50% verminder is, afhangend van die muurhoogte. Al die voorspellingmetodes wat getoets is was akkuraat in die beraming van die oorspoeling wanneer die verhouding van vryboord tot betekenisvolle golfhoogte ≤1.83 was. Vir nie-brekende golftoestande het strandprofiele met ’n lae helling (1:50) en wat wyd was meer oorspoeling tot gevolg gehad as strandprofiele wat steil (1:10) en nou was. ’n Verhoging in die strand se vlakke het die oorspoeling slegs verminder indien die diepte van die water vlak genoeg was om die golwe te laat breek voordat hulle die agterkant van die strand bereik het. Oorspoeling is gevind om te vermeeder met verlengde golflengte tot dat die golflengte só lank geword het dat die golwe in dieper water begin breek wat aanlieding tot verminderde oorspoeling gegee het. Daar word moontlike oplossings vir oorspoeling voorgestel gebaseer op twee strandvlakke en die implementering van ’n teruggebuigde strandmuur. Voorgestelde golfkruinvlakke vir die muur is al langs die lengte van die strand gemaak vir beide die 1:20- en 1:100-jaar watervlakke.