DOCSLIB.ORG

An Investigation Into Phytoplankton Blooms in the Vaal River and the Environmental Variables Responsible for Their Development and Decline

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
An Investigation Into Phytoplankton Blooms in the Vaal River and the Environmental Variables Responsible for Their Development and Decline AN INVESTIGATION INTO PHYTOPLANKTON BLOOMS IN THE VAAL RIVER AND THE ENVIRONMENTAL VARIABLES RESPONSIBLE FOR THEIR DEVELOPMENT AND DECLINE Final Report to the Water Research Commission by AJH Pieterse and Sanet Janse van Vuuren Department of Plant and Soil Sciences Potchefstroom University for Christian Higher Education Private Bag X6001 Potchefstroom 2520 WRC Report No 359/1/97 ISBN 1 86845 330 8 11 STEERING COMMITTEE Dr G Offringa (Chairman) Water Research Commission, Pretoria Mr AJ Dippenaar Goldfield Water, Bothaville Mr HM du Plessis Water Research Commission, Pretoria Dr S Mitchell Water Research Commission, Pretoria Mr K Morgan Western Transvaal Regional Water Company, Stilfontein Mr G Quibell Department of Water Affairs and Forestry, Pretoria Mr N Rossouw Watertek, CSIR, Pretoria Mr MC Steynberg Rand Water Board, Vereeniging Mr D Huyser & Ms AM du Toit (Secretariat) Water Research Commission, Pretoria Ill CONTENTS Executive summary iv List of Figures viii List of Tables xv 1. Introduction and objectives AJHPieterse 1 2. Phytoplankton production and photosynthetic characteristics in relation to environmental variables in the Vaal River at Balkfontein JC Roos, AJH Pieterse, JF Prinsloo 3 3. Environmental variables, abundance and seasonal succession of phytoplankton populations S Janse van Vuuren & AJH Pieterse 25 4. The effect of increased concentrations of total dissolved salts on algal species from the Vaal River JF Prinsloo & AJH Pieterse 157 5. Nutrient availability: phosphatase and nitrate reductase activity in the Vaal River and its phytoplankton E Coetzee & AJH Pieterse 185 6. Phytoplankton biomass and environmental variables in the Vaal River at Barrage and Stilfontein AJH Pieterse, M Smith & N Matthew 198 7. Modelling algal growth in the Vaal River AHJ Cloot, SW Schoombie, AJH Pieterse & JC Roos 212 8. Summary and conclusions AJHPieterse 227 Acknowledgments 234 Glossary of symbols 235 Glossary of concepts used in the text 237 IV EXECUTIVE SUMMARY AN INVESTIGATION INTO PHYTOPLANKTON BLOOMS IN THE VAAL RIVER AND THE ENVIRONMENTAL VARIABLES RESPONSIBLE FOR THEIR DEVELOPMENT AND DECLINE AJH Pieterse & Sanet Janse van Vuuren Department of Plant and Soil Sciences, PU for CHE, Potchefstroom When compared with similar studies on rivers in other regions of the world, it is clear that the Vaal River, although unique in many ways, also have characteristics in common with the other rivers. An investigation on the phytoplankton assemblages as well as the associated environmental variables and metabolic and other processes in the Vaal River, however, broadens our understanding of rivers in general. For this reason this particular study on the Vaal River is of general significance to all scientists interested in aquatic ecology and the utilisation and management of inland waters. The Vaal River is the most important and the most regulated river in South Africa. It is also a eutrophic system on account of high chlorophyll-a and inorganic nitrogen and phosphorus concentrations as well as high primary productivity rates. Massive developments of phytoplankton are experienced in certain sections, resulting in aesthetic problems, health hazards, interferences with treatment processes and problems in water distribution systems. Consequently, the causes and consequences of the wax and wane of phytoplankton assemblages in the Vaal River were investigated. The study showed that a variety of phytoplankton species (at least 124 species and varieties), occurred in the Vaal River during the study period. Green algae showed greatest species diversity. The greatest diversity of Cyanophyceae species were present at the Barrage, while the greatest diversity of Euglenophyceae species were present at the Balkfontein sampling locality. The phytoplankton community was dominated mainly by diatoms and green algae (which succeeded each other), as well as by blue-green algae during warmer periods. Different species succession patterns were demonstrated for the different sampling positions. At the Barrage, Parys and Balkfontein, different species succeeded one another within relatively small time spans. At Stilfontein a smaller number of species succeeded one another, possibly indicating more stable environmental conditions at this locality in the river. During the summer periods, diatoms tended to dominate in the Vaal River from January to August of each year, while the green algae were dominant from September to December. Dominance of diatoms during January to April and December, can be ascribed to blooms of Melosira granulata. Concentrations of unicellular centric diatoms were usually low during the summer periods, but they often dominated during the cold-water winter periods. Blue-green algae frequently occurred during the mid and late summer months of each year, especially at the Barrage, Stilfontein and Balkfontein sampling localities. Water temperature also affects solubility of silica and oxygen. Higher silica concentrations were usually present during summer periods when the water temperatures were higher, while lower Si concentrations were present during the winter. Indications of pollution and eutrophication were reflected in high chlorophyll-a concentrations in the Vaal River in comparison with other river systems. Periods of maximum chlorophyll-a concentration in the Vaal River occurred from January to March (summer) and again from July to November (winter-spring) of each year. Increased nutrient concentration in the Vaal River apparently increased the capacity of the water to support high production rates and to maintain large standing crops of phytoplankton. Higher discharge resulted in higher total suspended solids (TSS) concentration, higher nutrient concentration (i.e. N, P and Si), lower total dissolved salts (TDS), higher turbidity and thus in lower euphotic zone (Zeu) and underwater light climate (ULC). Very high levels of discharge can be responsible for a complete wash-out of the phytoplankton. The turbidity of Vaal River water at Balkfontein was lower during the period 1984 to 1991 than during previous years. Reduced turbidity might be due to the clearing effect of salinity or possibly to the presence of water hyacinths. Water hyacinths could have served as sediment and plant nutrient traps. Since 1991, however, increases in tubidity were observed. Decreased turbidity resulted in an improved under water light climate (ULC) which, in turn, was associated with reduced daily rates of areal photosynthesis during certain periods. The total dissolved salts (TDS) concentration in the Vaal River is high, with an average annual maximum of about 650 mg I"1 and a minimum concentration of about 400 mg I*1. The mean annual TDS concentration for the study period (1984 - 1993) was about 520 mg I"1 which is approximately four times higher than the global mean salinity of river water. An average increase rate of 25 mg I"1 per annum was calculated for the study period at both Stilfontein and Balkfontein. Based on the results of the present study, the Vaal River can be classified as a mixohaline system. The order of ionic prominence in the Vaal River 2 2+ + 2+ 2 at Balkfontein was SO4 " > > Ca > Cl" > Na > Mg and at Stilfontein it was SO4 - > > Cl > Ca2+ > Na+ > Mg2+. The major ionic contributor to the total dissolved salts of the 2 water was the anion SO4 \ Salinity was not the primary variable influencing algal growth, but dinoflagellate representatives (responsible for red-tides in the ocean) more frequently occurred in high salinity water, while blue-green algae occurred in water with relatively low salinities. Growth and carbon assimilation experiments indicated that different algae showed different sensitivities to TDS. Of the three algal species investigated, Cyclotella meneghiniana (a diatom) was the most sensitive and Monoraphidium circinale (a green alga) the least sensitive to increased dissolved salts. If the total dissolved salts concentration of Vaal River water increases with time, algal species that could persist over a wide range of salinities can be expected to be present most of the time. Of the species investigated, Monoraphidium circinale can be expected to become dominant under VI conditions of increased salinity. Cyclotella meneghiniana and Microcystis aeruginosa on the other hand, can be expected to be excluded from the water under conditions of increased salinity of 250 mg I"1 and above. The recent increased abundance of Oscillatoria simplidssima (another blue-green alga) in the Vaal River can possibly be attributed to temporary decreasing levels of salinity. Reduced annual DIN:DIP ratios suggested that the Vaal River at Balkfontein switched from a generally phosphorus limited system (1986 to 1990) to a potentially nitrogen limited system (1991 and 1993). The decrease in DIN:DIP ratio was caused by relatively low DIN concentrations and relatively high DIP concentrations. Switching inorganic nitrogen and phosphorus limitation influence algal biomass as well as the composition of the algal assemblages. The switching between Chlorophyceae (green algae) and Bacillariophyceae (diatoms) dominance is apparently partly determined by N:P ratios. Blue-green algae were most probably favoured by low DIN:DIP and TN:TP ratios. A shift from blue-green algae to other algal groups occurred if the TN:TP ratio increased. Increased phosphorus concentrations in the Vaal River (with a resultant decrease in DIN:DIP and thus TN:TP to less than five) will probably cause a shift in the algal assemblages from diatom and green algal dominance
Load more

Recommended publications
  • 112 Reports (January 2015)
    112 Reports (January 2015) Internal parasites – Roundworms (January 2015) jkccff Bethal, Ermelo, Grootvlei, Lydenburg, Middelburg, Nelspruit, Piet Retief, Standerton, Bapsfontein, Bronkhorstspruit, Krugersdorp, Onderstepoort, Pretoria, Bela - Bela, Modimolle, Mokopane, Polokwane, Vaalwater, Ventersdorp, Bethlehem, Bloemfontein, Bothaville, Clocolan, Frankfort, Harrismith, Hertzogville, Hoopstad, Kroonstad , Ladybrand/Excelsior , Memel, Parys, Reitz, Viljoenskroon, Villiers, Vrede, Wesselsbron, Zastron, Bergville, Dundee, Estcourt, Howick, Mooi River, Mtubatuba, Vryheid, Aliwal North, Graaff- Reinet, Humansdorp, Jeffreys Bay, Middelburg, Port Alfred, Somerset East, George, Heidelberg, Kimberley, Kuruman Internal parasites – Resistant roundworms (January 2015) jkccff Balfour, Nelspruit, Volksrust, Pretoria, Bloemhof,,,p, Bloemfontein, Hoopstad, Ladybrand/Excelsior, Reitz, Villiers, Aliwal North, Graaff-Reinet, Humansdorp x Internal parasites – Tapeworms (January 2015)jkccff Standerton, Volksrust, Bronkhorstspruit, Polokwane, Ventersdorp, Bethlehem, Hoopstad, Memel, Reitz, Villiers, Wesselsbron, Bergville, Graaff-Reinet, Humansdorp, Queenstown 00 Internal parasites – Tapeworms Cysticercosis (measles) January 2015 jkccff Nelspruit, Bapsfontein, Pietermaritzburg, Pongola 00 Internal parasites – Liver fluke worms (January 2015)jkccff Bethlehem, Ficksburg, Frankfort, Vrede, Dundee, Howick, Underberg, SEGSomerset East, George Internal parasites – Conical fluke (January 2015) jkccff Balfour, Standerton, Frankfort, Viljj,,,oenskroon, Zastron, Howick,
    [Show full text]
  • The Free State, South Africa
    Higher Education in Regional and City Development Higher Education in Regional and City Higher Education in Regional and City Development Development THE FREE STATE, SOUTH AFRICA The third largest of South Africa’s nine provinces, the Free State suffers from The Free State, unemployment, poverty and low skills. Only one-third of its working age adults are employed. 150 000 unemployed youth are outside of training and education. South Africa Centrally located and landlocked, the Free State lacks obvious regional assets and features a declining economy. Jaana Puukka, Patrick Dubarle, Holly McKiernan, How can the Free State develop a more inclusive labour market and education Jairam Reddy and Philip Wade. system? How can it address the long-term challenges of poverty, inequity and poor health? How can it turn the potential of its universities and FET-colleges into an active asset for regional development? This publication explores a range of helpful policy measures and institutional reforms to mobilise higher education for regional development. It is part of the series of the OECD reviews of Higher Education in Regional and City Development. These reviews help mobilise higher education institutions for economic, social and cultural development of cities and regions. They analyse how the higher education system T impacts upon regional and local development and bring together universities, other he Free State, South Africa higher education institutions and public and private agencies to identify strategic goals and to work towards them. CONTENTS Chapter 1. The Free State in context Chapter 2. Human capital and skills development in the Free State Chapter 3.
    [Show full text]
  • Chapter 1. Introduction
    1 Chapter 1. Introduction Once an English-speaking population was established in South Africa in the 19 th century, new unique dialects of English began to emerge in the colony, particularly in the Eastern Cape, as a result of dialect levelling and contact with indigenous groups and the L1 Dutch speaking population already present in the country (Lanham 1996). Recognition of South African English as a variety in its own right came only later in the next century. South African English, however, is not a homogenous dialect; there are many different strata present under this designation, which have been recognised and identified in terms of geographic location and social factors such as first language, ethnicity, social class and gender (Hooper 1944a; Lanham 1964, 1966, 1967b, 1978b, 1982, 1990, 1996; Bughwan 1970; Lanham & MacDonald 1979; Barnes 1986; Lass 1987b, 1995; Wood 1987; McCormick 1989; Chick 1991; Mesthrie 1992, 1993a; Branford 1994; Douglas 1994; Buthelezi 1995; Dagut 1995; Van Rooy 1995; Wade 1995, 1997; Gough 1996; Malan 1996; Smit 1996a, 1996b; Görlach 1998c; Van der Walt 2000; Van Rooy & Van Huyssteen 2000; de Klerk & Gough 2002; Van der Walt & Van Rooy 2002; Wissing 2002). English has taken different social roles throughout South Africa’s turbulent history and has presented many faces – as a language of oppression, a language of opportunity, a language of separation or exclusivity, and also as a language of unification. From any chosen theoretical perspective, the presence of English has always been a point of contention in South Africa, a combination of both threat and promise (Mawasha 1984; Alexander 1990, 2000; de Kadt 1993, 1993b; de Klerk & Bosch 1993, 1994; Mesthrie & McCormick 1993; Schmied 1995; Wade 1995, 1997; de Klerk 1996b, 2000; Granville et al.
    [Show full text]
  • Prospecting Work Programme
    1 NAME OF APPLICANT: WESTERN ALLEN RIDGE GOLD MINES (Pty) Ltd REFERENCE NUMBER: FS 30/5/1/1/2/10486 PR PROSPECTING WORK PROGRAMME SUBMITTED FOR A PROSPECTING RIGHT APPLICATION WITHOUT BULK SAMPLING AS REQUIRED IN TERMS OF SECTION 16 READ TOGETHER WITH REGULATION 7(1) OF THE MINERAL AND PETROLEUM RESOURCES DEVELOPMENT ACT (ACT 28 of 2002) 2 STANDARD DIRECTIVE All applicants for mining rights are herewith, in terms of the provisions of Section 16 and in terms of Regulation 7(1) of the Mineral and Petroleum Resources Development Act, directed to submit a Prospecting Work Programme, strictly under the following headings and in the following format together with the application for a prospecting right. 3 1. REGULATION 7.1.(a): FULL PARTICULARS OF THE APPLICANT Table 1: Applicant’s Contact Details ITEM COMPANY CONTACT DETAILS Name: Western Allen Ridge Gold Mines (Pty) Ltd. Tel no: 011 431 1191 Fax no: 011 431 1193 / 086 661 9323 Cellular no: 079 881 9323 E-mail address: [email protected] Postal address: P.O. Box 2591 Cresta 2118 Table 2: Consultant’s Details ITEM CONSULTANT CONTACT DETAILS (If applicable) Name Dunrose Trading 186 (Pty) Ltd t/a Shango Solutions Tel no 011 678 6504 Fax no: 011 678 9731 Cellular no E-mail address [email protected] Postal address P O Box 2591 Cresta 2118 4 2. REGULATION 7(1)(b): PLAN CONTEMPLATED IN REGULATION 2(2) SHOWING THE LAND TO WHICH THE APPLICATION RELATES. 5 3. REGULATION 7(1)(c): THE REGISTERED DESCRIPTION OF THE LAND TO WHICH THE APPLICATION RELATES Farm Farm Name Portion District Province
    [Show full text]
  • Interview with Molefi John Phasha
    Project name: Alternative History Project Date of interview: 2007-07-24 Location of interview: Rammolutsi, Free State Language of interview: English Name of Interviewer/s: Dale McKinley & Ahmed Veriava Name of Interviewee/s: Molefi John Phasha Name of transcriber: Moses Moremi Audio file name: AHP_RAM_PhashaMolefiJohn_20070724 INTERVIEW WITH MOLEFI JOHN PHASHA Dale McKinley (DM): Will you, just for the record, state your full name? Molefi Phasha (MP): I am Molefi John Phasha. I stay here at Rammolutsi at number 3979, under Viljoenskroon. DM: How long have you been staying here at Rammolutsi? MP: Not so long, the last place that I lived was Bothaville. I became a pensioner and I had to come live here. I left my previous wife and then I took my new wife – who passed in April – and now I’m staying alone her with kids. That’s my life. AV: How many kids do you have? MP: 3 boys. One boy and two twins. The younger kids are 12 years old, and the older one is 15 years old. DM: Where were you born and raised? MP: I was born in Bothaville and raised there. I started working there at a hotel because I couldn’t go further on school. So, after Std 6 I just had to work until I can not go further. DM: How far is Bothaville, from here? MP: It is about 50 - 59 kilometres. DM: What year did you start working in that hotel? MP: When I started working at the hotel I was a waiter. Then I got work at the furnisher and then I became a supervisor.
    [Show full text]
  • SWARTBOOI, NTLELI GABRIEL 1St Applicant TSOAI
    5 IN THE CONSTITUTIONAL COURT OF SOUTH AFRICA CASE NO : In the matter between : SWARTBOOI, NTLELI GABRIEL 1st Applicant TSOAI, GODFREY MOJAKI 2nd Applicant THEDISI, SABATA ELIAS 3rd Applicant MATSEPE, SANAH MOTSHEHOANE 4th Applicant MATUBE, DANIEL NGAKE 5th Applicant PHOLO, JACOB 6th Applicant NDONGA, TSIETSE ANDRIES 7th Applicant LETSHOARA, KHUMISI JOSEPH 8th Applicant MOLETSANE, MOLIFI ERNEST 9th Applicant SWARTBOOI, NTSOKOLO APRIL 10th Applicant MEPHA, MERRIAM PULANE 11th Applicant KGANG, BETHUEL POGISHO 12th Applicant MOLISENYANE, KONTSANE JONAS 13th Applicant MATHIBE, MAKGOBE REGINA 14th Applicant LEKHELEBANE, LIPHAPANG DAVID 15th Applicant MASUMPA, TLANGANISO ISHMAEL 16th Applicant LESEANE, MARTHA DIKELEDI 17th Applicant MOGOJE, THEKO AUBOU 18th Applicant and BRINK, LILIAN RAY 1st Respondent NIEUWOUDT, GERITT 2nd Respondent FOUNDING AFFIDAVIT I, the undersigned, NTLELI GABRIEL SWARTBOOI do hereby make oath and say : 6 1 I am an adult male employed at the Civic Centre, Preller Street, Bothaville. I am the speaker of the Municipality of Nala Local Municipality. I am the First Applicant in this matter. 2 The facts contained herein are within my personal knowledge and are both true and correct. 3 The Second Applicant is GODFREY MOJAKI TSOAI, an adult male Councillor of the Nala Local Municipality who resides at 351 Mpomela Street, Kgotsong, Bothaville. The Second Applicant is also the mayor of the Nala Local Council. 4 The Third Applicant is SABATA ELIAS THEDISI, an adult male Councillor of the Nala Local Municipality who resides at Stand No.3697, Monyakeng, Wesselsbron. 5 The Fourth Applicant is SANAH MOTSHEHOANE MATSEPE, an adult female Councillor of the Nala Local Municipality who resides at 808 Swartbooi Street, Monyakeng, Wesselsbron.
    [Show full text]
  • South Africa)
    FREE STATE PROFILE (South Africa) Lochner Marais University of the Free State Bloemfontein, SA OECD Roundtable on Higher Education in Regional and City Development, 16 September 2010 [email protected] 1 Map 4.7: Areas with development potential in the Free State, 2006 Mining SASOLBURG Location PARYS DENEYSVILLE ORANJEVILLE VREDEFORT VILLIERS FREE STATE PROVINCIAL GOVERNMENT VILJOENSKROON KOPPIES CORNELIA HEILBRON FRANKFORT BOTHAVILLE Legend VREDE Towns EDENVILLE TWEELING Limited Combined Potential KROONSTAD Int PETRUS STEYN MEMEL ALLANRIDGE REITZ Below Average Combined Potential HOOPSTAD WESSELSBRON WARDEN ODENDAALSRUS Agric LINDLEY STEYNSRUST Above Average Combined Potential WELKOM HENNENMAN ARLINGTON VENTERSBURG HERTZOGVILLE VIRGINIA High Combined Potential BETHLEHEM Local municipality BULTFONTEIN HARRISMITH THEUNISSEN PAUL ROUX KESTELL SENEKAL PovertyLimited Combined Potential WINBURG ROSENDAL CLARENS PHUTHADITJHABA BOSHOF Below Average Combined Potential FOURIESBURG DEALESVILLE BRANDFORT MARQUARD nodeAbove Average Combined Potential SOUTPAN VERKEERDEVLEI FICKSBURG High Combined Potential CLOCOLAN EXCELSIOR JACOBSDAL PETRUSBURG BLOEMFONTEIN THABA NCHU LADYBRAND LOCALITY PLAN TWEESPRUIT Economic BOTSHABELO THABA PATSHOA KOFFIEFONTEIN OPPERMANSDORP Power HOBHOUSE DEWETSDORP REDDERSBURG EDENBURG WEPENER LUCKHOFF FAURESMITH houses JAGERSFONTEIN VAN STADENSRUST TROMPSBURG SMITHFIELD DEPARTMENT LOCAL GOVERNMENT & HOUSING PHILIPPOLIS SPRINGFONTEIN Arid SPATIAL PLANNING DIRECTORATE ZASTRON SPATIAL INFORMATION SERVICES ROUXVILLE BETHULIE
    [Show full text]
  • South African Jewish Board of Deputies Report of The
    The South African Jewish Board of Deputies JL 1r REPORT of the Executive Council for the period July 1st, 1933, to April 30th, 1935. To be submitted to the Eleventh Congress at Johannesburg, May 19th and 20th, 1935. <י .H.W.V. 8. Co י É> S . 0 5 Americanist Commiitae LIBRARY 1 South African Jewish Board of Deputies. EXECUTIVE COUNCIL. President : Hirsch Hillman, Johannesburg. Vice-President» : S. Raphaely, Johannesburg. Morris Alexander, K.C., M.P., Cape Town. H. Moss-Morris, Durban. J. Philips, Bloemfontein. Hon. Treasurer: Dr. Max Greenberg. Members of Executive Council: B. Alexander. J. Alexander. J. H. Barnett. Harry Carter, M.P.C. Prof. Dr. S. Herbert Frankel. G. A. Friendly. Dr. H. Gluckman. J. Jackson. H. Katzenellenbogen. The Chief Rabbi, Prof. Dr. j. L. Landau, M.A., Ph.D. ^ C. Lyons. ^ H. H. Morris Esq., K.C. ^י. .B. L. Pencharz A. Schauder. ^ Dr. E. B. Woolff, M.P.C. V 2 CONSTITUENT BODIES. The Board's Constituent Bodies are as. follows :— JOHANNESBURG (Transvaal). 1. Anykster Sick Benefit and Benevolent Society. 2. Agoodas Achim Society. 3. Beth Hamedrash Hagodel. 4. Berea Hebrew Congregation. 5. Bertrams Hebrew Congregation. 6. Braamfontein Hebrew Congregation. 7. Chassidim Congregation. 8. Club of Polish Jews. 9. Doornfontein Hebrew:: Congregation.^;7 10. Eastern Hebrew Benevolent Society. 11. Fordsburg Hebrew Congregation. 12. Grodno Sifck Benefit and Benevolent Society. 13. Habonim. 14. Hatechiya Organisation. 15. H.O.D. Dr. Herzl Lodge. 16. H.O.D. Sir Moses Montefiore Lodge. 17. Jeppes Hebrew Congregation, 18. Johannesburg Jewish Guild. 19. Johannesburg Jewish Helping Hand and Burial Society.
    [Show full text]
  • 112 Reports (February 2015)
    112 Reports (February 2015) Internal parasites – Roundworms (February 2015) jkccff Balfour, Bethal, Ermelo, Grootvlei, Middelburg, Nelspruit, Piet Retief, Bronkhorstspruit, Krugersdorp, Nigel, Pretoria, Lephalale, Makhado, Modimolle, Mokopane, Polokwane, Christiana, Stella, Bethlehem, Bothaville, Bultfontein, Clocolan, Ficksburg, Frankfort, Harrismith, Hertzogville, Hoopstad, Kroonstad, Ladybrand/Excelsior, Memel , Reitz , Viljoenskroon, Villiers, Wesselsbron, Winburg, Zastron, Bergville, Dundee, Estcourt, Howick, Mooi River, Mtubatuba, Aliwal North, Graaff-Reinet, Humansdorp, Middelburg, Port Alfred, Queenstown, Uitenhage, George, Heidelberg, Riversdale Internal parasites – Resistant roundworms (February 2015) jkccff Ermelo, Middelburg, Nelspruit, Standerton,,,gp, Volksrust, Krugersdorp, Pretoria, Christiana, Ventersdorp, Bethlehem, Clocolan, Reitz, Villiers, Bergville, Howick, Aliwal North, Graaff- Reinet, Ceres, George x Internal parasites – Tapeworms (February 2015)jkccff Volksrust, Bronkhorstspruit, Pretoria, Polokwane, Leeudoringstad, Bethlehem, Clocolan , Memel , Villiers , Vrede, Wesselsbron, Humansdorp, Queenstown, Riversdale 00 Internal parasites – Tapeworms Cysticercosis (measles) (Fe bruary 2015) jkccff Bapsfontein, Ventersdorp, Bultfontein, Pietermaritzburg, 00 Internal parasites – Liver fluke worms (February 2015)jkccff Ermelo, Grootvlei, Volksrust, Polokwane, Bethlehem, Clocolan, Fick s burg, H arr ismi th , R ei tz, Humansdorp, Darling, George, Oudtshoorn Internal parasites – Conical fluke (February 2015) jkccff Balfour,
    [Show full text]
  • A Spatial and Temporal Analysis of the Changes in Alien Macrophyte
    A spatial and temporal analysis of the changes in alien macrophyte communities and a baseline assessment of the macroinvertebrates associated with Eurasian water- milfoil, Myriophyllum spicatum L. (Haloragaceae) in the Vaal River. Thesis Submitted in fulfilment of the requirements for the degree of Master of Science By Colin Justin Fordham Department of Zoology and Entomology Rhodes University P.O. Box 94 Grahamstown 6140 Date: January 2012 ABSTRACT The majority of South Africa’s fresh water (lotic and lentic), is eutrophic and this has resulted in water hyacinth, Eichhornia crassipes (C.Mart.) Solms. (Pontederiaceae) becoming South Africa’s most damaging aquatic macrophyte. Recently however, concerns have also been voiced over the presence of highly invasive submerged macrophyte species, such as Eurasian water-milfoil, Myriophyllum spicatum L. (Haloragaceae) in the Vaal River. Interaction studies between floating and submerged macrophytes have shown that floating macrophyte dominance restricts light penetration into the water column shading out submerged macrophytes while submerged macrophyte dominance reduces nutrient availability in the water column limiting floating macrophyte growth. This cycle ensures that these species cannot coexist in the same habitat for extended periods of time. The aims of this thesis were to: 1. Investigate changes in the historical and current macrophyte dominance in the Vaal River 2. Determine whether these changes could be attributed to stochastic events, such as floods and herbicide control measures. 3. The physio-chemical conditions of the water column, and whether pressure from herbivory by macroinvertebrates had possibly influenced Eurasian water-milfoil’s ability to dominate. Spatial and temporal analysis of satellite imagery revealed that water hyacinth and submerged macrophyte species dominated different regions of the study area over different periods of time from 2006 to 2010.
    [Show full text]
  • 143 Reports February 2020 Internal Parasites – Roundworms (February 2020)
    143 Reports February 2020 Internal parasites – Roundworms (February 2020) Balfour, Bethal, Ermelo, Hendrina, Lydenburg, jkccff Middelburg, Nelspruit, Standerton, Volksrust, Bapsfontein, Bronkhorstspruit, Hammanskraal, Magaliesburg, Nigel, Onderstepoort, Pretoria, Bela- Bela, Makhado, Mokopane, Tzaneen, Vaalwater, Brits, Christiana, Klerksdorp, Koster/Ventersdorp, Leeudoringstad, Ottosdal, Potchefstroom, Rustenburg, Stella, Vryburg, Bloemfontein, Clocolan, Excelsior/Ladybrand, Ficksburg, Bothaville, Frankfort, Gariep Dam, Hoopstad, Kroonstad, Memel, Parys, Reitz, Viljoenskroon, Villiers, Vrede, Wesselsbron, Zastron, Camperdown, Dundee, Estcourt, Howick, Kokstad, Mtubatuba, Pietermaritzburg, Vryheid, Adelaide, Aliwal North, Cradock, Graaff-Reinet, Port Alfred, Somersset East, Steynsburg, Stutterheim, Witelsbos, Beaufort West, Caledon, Darling, George, Moorreesburg, Stellenbosch, Colesberg, Kimberley Internal parasites – Resistant roundworms (February 2020) Balfour, Bronkhorstspruit, Pretoria, Christiana, jkccff Bloemfontein, Bothaville, Clocolan, Excelsior/Ladybrand, Hoopstad, Memel, Reitz, Viljoenskroon, Villiers, Dundee, Vryheid, Cradock, Graaff-Reinet x Internal parasites – Tapeworms (February 2020)jkccff Balfour, Lydenburg, Volksrust, Bronkhorstspruit, Pretoria, Koster/Ventersdorp, Rustenburg, Tzaneen, Bloemfontein, Bultfontein, Ficksburg, Kroonstad, Reitz, Vijoenskroon, Vrede, Estcourt, Mooi River, Graaff-Reinet, Somerset East 00 Internal parasites – Tapeworms Cysticercosis (measles) (February 2020) jkccff Nelspruit, Magaliesburg, Parys,
    [Show full text]
  • Rural Livelihoods, Institutions and Vulnerability in South Africa
    Working Paper Series ISSN 1470-2320 2002 No. 02-30 RURAL LIVELIHOODS, INSTITUTIONS AND VULNERABILITY IN SOUTH AFRICA Dr Elizabeth Francis Published: April 2002 Development Studies Institute London School of Economics and Political Science Houghton Street Tel: +44 (020) 7955-7425 London Fax: +44 (020) 7955-6844 WC2A 2AE UK Email: [email protected] Web site: www.lse.ac.uk/depts/destin The London School of Economics is a School of the University of London. It is a charity and is incorporated in England as a company limited by guarantee under the Companies Act (Reg. No. 70527). Rural Livelihoods, Institutions and Vulnerability in South Africa∗ Elizabeth Francis April, 2002 Drawing on a case study from North West Province, this paper examines how, and why, rural livelihoods have changed in one of the former bantustans over the past four decades. It focuses on the nature and extent of processes of differentiation and the resources that have been critical in such processes. It examines the major risks different kinds of people face in their efforts to construct and reconstruct livelihoods and their responses to these risks. The sources of these risks include institutions governing resource access and contract enforcement, together with labour and commodity markets. Responses have often taken the form of livelihood diversification, between activities and across space, putting a premium on access to information and social networks, as well as to the State. Others have responded to risk by clustering around a person with a regular income. Policy interventions to promote poverty reduction must combine support for the generation of livelihoods with institutional reform to reduce vulnerability to risk.
    [Show full text]