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Effect of Ca, K and B supply on water-stress induced chlorophyll loss from tobacco and cotton leaf discs
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: ElizabethA. Davies --- , England N. J.J. Combrink --- , Republic of South AfricaA study was made of the influence of Ca:K ratios and B levels on the chlorophyll content of tobacco and cotton leaves grown under glasshouse conditions. Excised leaf discs were floated on a solution of polyethylene glycol 6000 to study... -
The association between residual chlorophyll and grassy taste in black tea
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: L.J. van Lelyveld --- , Republic of South Africa B.L. Smith --- , Republic of South AfricaThe ‘grassy’ taste in some South African and Central African black teas is not up to tea tasters' and buyers' standards. It has been shown by a number of researchers that this taste is associated with volatiles in the tea... -
Nitrogen fertilization of tea: Effect of tea leaf plucking criteria on chlorophyll and quality parameters
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: L.J. van Lelyveld --- , Republic of South Africa Connie Fraser --- , Republic of South Africa B.L. Smith --- , Republic of South Africa G. Visser --- , Republic of South AfricaThe purpose of this investigation was to establish the possible effect of plucking criteria on the quality of black tea produced with different levels of nitrogen fertilization. Increases in leaf age (norms) resulted in increased total chlorophyll in fresh green... -
Leaf characters of various tea clones in relation to quality
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: P.J. Robbertse --- , Republic of South Africa Elsie M.A. Steyn --- , Republic of South AfricaThe leaves of ten different tea clones were investigated to explore the possibility that structural differences exist between clones and that morphological characters relate to the quality of the infusion. Our results revealed a significant negative correlation between TF-values and... -
Use of chlorophyll a fluorescence in screening for herbicide susceptibility in several Nicotiana tabacum L. cultivars and breeding lines
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: L. van Rensburg --- Faculty of Natural Sciences, Department of Plant and Soil Sciences, Private Bag X6001, Republic of South Africa G. H.J. Krüger --- Faculty of Natural Sciences, Department of Plant and Soil Sciences, Private Bag X6001, Republic of South Africa C.R. Nolte --- , Republic of South AfricaPossible differential sensitivity of newly released tobacco cultivars to different herbicides must be determined, as possible unfavourable combinations could exist which may have large financial implications in terms of cultivars bred, herbicide and tobacco line combinations used, and concentrations in... -
Measuring water stress in Pinus patula Schiede ex Schlect. & Cham. seedlings
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: C.A. Rolando --- , K.M. Little --- ,A pot trial was conducted to investigate measures of water stress for Pinus patula seedlings planted for commercial forestry in South Africa. The objectives were to determine the efficacy of different equipment for quantifying water stress, and the effect of... -
Preliminary assessment of bambara groundnut (Vigna subterranea L.) landraces for temperature and water stress tolerance under field conditions in Botswana
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: A. Sesay --- Botswana College of Agriculture, Botswana T. Mpuisang --- Botswana College of Agriculture, Botswana T.S. Morake --- Department of Agricultural Research, Ministry of Agriculture, I. Al-Shareef --- School of Bioscience, Department of Plant and Crop Science, UK H.J. Chepete --- Botswana College of Agriculture, Botswana B. Moseki --- Department of Biological Sciences, BotswanaField experiments were conducted in 2006/07 and 2007/08 in Botswana to study the response of bambara groundnut to heat stress (2006/07 season) and to heat stress and soil moisture deficit stress (2007/08 season). In both seasons selected bambara groundnut landraces... -
Open-top chamber facility to study air pollution impacts in South Africa. Part II: SO2–drought interactions on yield, photosynthesis and symbiotic nitrogen fixation in soybean
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: E Heyneke --- School of Environmental Science and Development, South Africa AJ Strauss --- School of Environmental Science and Development, South Africa RJ Strasser --- Bioenergetics Laboratory, Switzerland GHJ Krüger --- School of Environmental Science and Development, South AfricaSouth Africa has an extremely energy-intensive economy, resulting in substantial air pollution through its coal-fired power stations. Modelled sulphur dioxide (SO2) concentrations on the central Highveld mostly range between 10 and 50 ppb, exceeding 50 ppb in source areas. Well-watered... -
Growth, phenological and yield responses of a bambara groundnut (Vigna subterranea (L.) Verdc.) landrace to imposed water stress under field conditions
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Tafadzwanashe Mabhaudhi --- Crop Science, School of Agricultural, Earth and Environmental Sciences, South Africa AlbertT Modi --- Crop Science, School of Agricultural, Earth and Environmental Sciences, South AfricaBambara groundnut (Vigna subterranea (L.) Verdc.) is an underutilised species with potential to contribute nutritional and food security in marginal areas. Growth, phenology and yield of a local bambara groundnut landrace from Jozini, KwaZulu-Natal, characterised into three selections according to... -
Elucidation of seasonal pigmentation patterns in the involucral leaves of Leucadendron ‘Safari Sunset’
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Michael Schmeisser --- Department of Horticultural Science, South Africa Gerard J Jacobs --- Department of Horticultural Science, South Africa Willem J Steyn --- Department of Horticultural Science, South AfricaThis study investigates seasonal pigmentation patterns found in the involucral leaves of Leucadendron ‘Safari Sunset’, with the long-term aim of colour manipulation. Treatments comprised deconed shoots and shoots in which the opening of the flower head was physically prevented. During... -
The effect of canola (Brassica napus) as a biofumigant on soil microbial communities and plant vitality: a pot study
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Clarissa Potgieter --- North-West University, South Africa Misha De Beer --- North-West University, South Africa Sarina Claassens --- North-West University, South AfricaCanola (Brassica napus) may be incorporated into soil as a biofumigant for control of pathogens such as Sclerotinia sclerotiorum. Yet, the effect of biofumigants on natural microbial communities required to maintain soil functions is still unclear. A pot experiment with... -
Identification and classification of vertical chlorophyll patterns in the Benguela upwelling system and Angola-Benguela front using an artificial neural network
Item type: Journal Article • Journal: South African Journal of Marine Science • Authors: N. F. Silulwane A. J. Richardson F. A. Shillington B. A. Mitchell-InnesInformation on the vertical chlorophyll structure in the ocean is important for estimating integrated chlorophyll a and primary production from satellite. For this study, vertical chlorophyll profiles from the Benguela upwelling system and the Angola-Benguela front were collected in winter... -
THE DETERMINATION OF CHLOROPHYLL
a IN WATER CONTAINING SEDIMENTItem type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa • Authors: D.C. Grobler --- Department of Water Affairs, South Africa Elizabeth Davies --- Department of Water Affairs, South AfricaThe presence of sediment at concentrations of 0,2% by mass in water samples significantly lowered the amount of chlorophyll a that could be measured. Two types of sediment differed in their ability to lower the chlorophyll a concentration. The chemically... -
ZOOPLANKTON AND ENVIRONMENTAL CONDITIONS IN GROENVLEI, SOUTHERN CAPE, DURING 1976
Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa • Authors: D.J. Coetzee --- Cape Department of Nature and Environmental Conservation, South AfricaThe zooplankton and environmental conditions in Groenvlei were studied during 1976 as part of an overall ecological study of the zooplankton of the Wilderness Lakes system. The Groenvlei water was found to be well mixed and low in dissolved PO4−P,... -
ZOOPLANKTON BIOMASS OF SOME TRANSVAAL IMPOUNDMENTS AND ITS RELATIONSHIP TO TROPHIC STATUS
Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa • Authors: M.T. Seaman --- , South Africa R.D. Walmsley --- , South Africa C.J. Alexander --- , South AfricaThe zooplankton biomass characteristics of 11 South African impoundments were investigated to assess the value of zooplankton biomass as a trophic status index. Mean annual zooplankton biomasses ranged from 0,38 to 5,32 g m−2, compared with the mean annual chlorophyll... -
OBSERVATTVNS ON THE UNDERWATER LIGHT FIELD OF TWO HWERTROPHIC, SOUTH AFRICAN IMPOUNDMENTS
Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa • Authors: R.D. Robarts --- , South Africa T. Zohary --- , South Africa F. Ojeda --- , Chile C. C.E. Lovengreen --- , Chile R.D. Walmsley --- ,The spectral composition of the underwater light field was examined in two hypertrophic South African Impoundments (Hartbeespoort and Roodeplaat Dams) under a range of inorganic turbidities and chlorophyll α concentrations. The data indicated that inorganic turbidity and gilvin were dominant... -
LEAF AREA AS A MEASURE OF STANDING CROP OF FLOATING AQUATIC MACROPHYTES
Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa • Authors: P.C. Keulder --- Department of Botany, South AfricaLeaf area is evaluated as a measure of standing crop of Salvinia molesta Mitchell and Azolla filiculoides Lam. cultures under controlled conditions. Growth rates as derived from leaf area determinations agreed with pigment extractions and fresh and dry weight measures... -
OBSERVATIONS ON THE UNDERWATER LIGHT FIELD OF TWO HYPERTROPHIC SOUTH AFRICAN IMPOUNDMENTS
Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa • Authors: R.D. Robarts --- National Institute for Water Research, South Africa T. Zohary --- National Institute for Water Research, South Africa F. Ojeda --- Institute of Physics, Chile C. C.E. Lovengreen --- Institute of Physics, Chile R.D. Walmsley --- Foundation for Research and Development,The spectral composition of the underwater light field was examined in two hypertrophic South African impoundments (Hartbeespoort and Roodeplaat Dams) under a range of inorganic turbidities and chlorophyll a concentrations. The data indicated that inorganic turbidity and gilvin were dominant... -
THE EFFECTS OF DESIGN AND OPERATION ON THE EFFICIENCY OF HOSEPIPES AS WATER COLUMN SAMPLERS FOR PHYTOPLANKTON
Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa • Authors: Tamar Zohary --- , South Africa P.J. Ashton --- , South AfricaThe efficiency of 5 different hosepipe samplers in providing representative water column samples was tested by comparing the chlorophyll a concentrations in these samples with those obtained by integrating discrete depth samples collected with a Van Dorn sampler, in two... -
CHLOROPHYLL-a CONCENTRATION IN THE LOWER KAFUE RIVER AND CHONGWE RIVER BASINS
Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa • Authors: Petr Obrdlik --- , Federal Republic of GermanyThe concentration of chlorophyll a was measured in the warm monomictic impoundment, Itezhi-tezhi Lake ([xbar] = 2,00 mg m−3); in the small, slightly polluted Chongwe Dam ([xbar] = 11,0 mg m−3); and in the temporary Mungasiya River ([xbar] = 53,4... -
APPLICATION OF LAVSOE, AN EUTROPHICATION MODEL, TO BLOEMHOF DAM
Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa • Authors: J.N. Rossouw --- ,In 1985 the Department of Water Affairs introduced an effluent phosphate standard of 1 mg l−1 (as P) in seven potentially sensitive catchments. Although this is an uniform standard, permits can be granted for effluents to exceed the standard in... -
Covariance Analysis of Chlorophyll Distribution in the Sundays River Estuary, Eastern Cape
Item type: Journal Article • Journal: Southern African Journal of Aquatic Sciences • Authors: T. Hilmer --- Department of Botany, South Africa G.C. Bate --- Department of Botany, South AfricaAn analysis of covariance performed on chlorophyll a distribution data from the Sundays River estuary identified five persistent water masses with significantly different chlorophyll a contents. These corresponded to different hydrodynamic regions within the estuary. The relationship between salinity and... -
Effects of storage conditions on chlorophyll content in diploid black wattle (Acacia mearnsii)
Item type: Journal Article • Journal: The Southern African Forestry Journal • Authors: S. Mathura S. L. Beck A. FosseyBlack wattle (Acacia mearnsii de Wild) is a commercially important forestry species in South Africa, however, being an exotic it is also seen as an invader of indigenous vegetation. Research into producing a sterile variety is underway and one such... -
Limnology of southern African coastal lakes — new vistas from Mozambique
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: RobC Hart Custodio BoaneFourteen mostly small, isolated, and relatively deep coastal inundation lakes were surveyed during the cool season (August) of 1996. No thermal or chemical stratification existed, but near-bottom hypoxia was evident in several systems. Ionic conductivity varied quite widely, but was... -
Ecophysiological responses of the salt marsh grass Spartina maritima to salinity
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: G Naidoo --- School of Biological and Conservation Sciences, South Africa Y Naidoo --- School of Biological and Conservation Sciences, South Africa P Achar --- Department of Biological and Physical Sciences, USAThe effects of salinity on growth and productivity of Spartina maritima (Curtis) Fernald were investigated in glasshouse and field experiments in 2008. In the glasshouse study, plants were subjected to 2%, 10%, 20%, 40% and 80% sea water, with tidal... -
Activity and feeding of Dotilla fenestrata (Brachyura: Ocypodidae) in a warm, temperate South African estuary
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: C Bulcao --- Department of Zoology and Entomology, South Africa AN Hodgson --- Department of Zoology and Entomology, South AfricaThe activity of and consumption of organic material by the sand-bubbler crab Dotilla fenestrata was studied over neap and spring tides on a sheltered sand bank close to the mouth of the warm, temperate Kowie Estuary, South Africa. Crabs emerged... -
Physical and chemical characteristics of the Tanzanian inshore and offshore waters of Lake Victoria in 2005–2008
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: GW Ngupula --- , Tanzania CN Ezekiel --- , Tanzania IA Kimirei --- , Tanzania E Mboni --- , Tanzania BB Kashindye --- , TanzaniaAssuming that the inshore and offshore waters of Lake Victoria are impacted differently by human activities in its catchment, this study investigated the water quality dynamics of the lake. A total of 29 stations were sampled in 2005–2008 for dissolved... -
Patterns of microbial activity in the shallow bottom sediments of Lake Manzala, Egypt
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: M Bahgat --- Botany Department, Egypt FM El Fawal --- Geology Department, Egypt F Al-Misned --- Department of Zoology, College of Sciences, Saudi Arabia HA El-Serehy --- Department of Zoology, College of Sciences, Saudi Arabia S Shaheen --- Geology Department, EgyptGeneral microbial activity, determined by hydrolysis of fluoresceine diacetate (FDA), was investigated in two sediment cores collected from Manzala Lake during November 2011. FDA hydrolysis positively correlated with total bacterial counts, bacterial biomass and chlorophyll a in both cores. The... -
CHLOROPHYLL-a CONCENTRATION IN THE LOWER KAFUE RIVER AND CHONGWE RIVER BASINS
Item type: Journal Article • Journal: Southern African Journal of Child and Adolescent Mental Health • Authors: Petr Obrdlik --- , Federal Republic of GermanyThe concentration of chlorophyll a was measured in the warm monomictic impoundment, Itezhi-tezhí Lake ([xbar] = 2,00 mg m−3); in the small, slightly polluted Chongwe Dam ([xbar] = 11,0 mg m−3); and in the temporary Mungasiya River ([xbar] = 53,4... -
APPLICATION OF LAVSOE, AN EUTROPHICATION MODEL, TO BLOEMHOF DAM
Item type: Journal Article • Journal: Southern African Journal of Child and Adolescent Mental Health • Authors: J.N. Rossouw --- ,In 1985 the Department of Water Affairs introduced an effluent phosphate standard of 1 mg l−1 (as P) in seven potentially sensitive catchments. Although this is an uniform standard, permits can be granted for effluents to exceed the standard in... -
Climatology and Variability of Sea Surface Temperature and Surface Chlorophyll in the Benguela and Agulhas Ecosystems As Observed by Satellite Imagery
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: H. Demarcq R. G. Barlow F. A. ShillingtonA climatology of satellite-derived sea surface semperature (SST) and surface chlorophyll a concentration (Chl), and their associated variability at time-scales from weeks to years, was constructed for the Benguela and Agulhas ecosystems. Global area coverage data at 4.5 km spatial... -
Distribution of nutrients, chlorophyll and phytoplankton primary production in relation to hydrographic structures bordering the Benguela-Angolan frontal region
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: N Wasmund H-U Lass G NauschThe aim of this study was to determine the characteristic rates of phytoplankton production in water bodies bordering the Benguela-Angolan frontal region and differing in their hydrographic, hydrochemical and biological properties. Two cruises were undertaken in the vicinity of the... -
Remotely sensed variability of temperature and chlorophyll in the southern Benguela: upwelling frequency and phytoplankton response
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: SJ Weeks R Barlow C Roy FA ShillingtonHigh-resolution (1km) satellite data from the NOAA AVHRR (Advanced Very High Resolution Radiometer) and OrbView-2 SeaWiFS (Sea-viewing Wide Field-of-view Sensor) are used to investigate the upper layer dynamics of the southern Benguela ecosystem in more detailed space and time scales... -
Broad-scale distribution patterns of sardine and their predators in relation to remotely sensed environmental conditions during the KwaZulu-Natal sardine run
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: SH O’Donoghue --- School of Biological and Conservation Sciences, South Africa L Drapeau --- , France VM Peddemors --- School of Biological and Conservation Sciences, South AfricaThe annual movement of South African sardine Sardinops sagax up the east coast of South Africa, known as the ‘sardine run’, was investigated using data from aerial surveys for the period 1988–2005 and compared with remotely sensed sea surface temperature... -
Abundance and distribution of avian and marine mammal predators of sardine observed during the 2005 KwaZulu-Natal sardine run survey
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: SH O’Donoghue --- School of Biological and Conservation Sciences, South Africa PA Whittington --- Department of Zoology, PO Box 77000, South Africa BM Dyer --- Oceans and Coasts, Department of Environmental Affairs, South Africa VM Peddemors --- School of Biological and Conservation Sciences, South AfricaOpportunistic observations to determine the relative abundance and distribution of marine mammal and seabird predators of sardine Sardinops sagax were carried out during a dedicated multidisciplinary research survey off the South African east coast in June and July of 2005... -
Seasonal fluctuations in occurrence of inshore Bryde's whales in Plettenberg Bay, South Africa, with notes on feeding and multispecies associations
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: GS Penry --- , UK VG Cockcroft --- Department of Zoology, Nelson Mandela Metropolitan University, South Africa PS Hammond --- , UKSeasonal fluctuations in the occurrence of inshore South African Bryde's whales Balaenoptera edeni were investigated between November 2005 and June 2008. Sighting data were collected in Plettenberg Bay on the south-east coast of South Africa. Bryde's whale occurrence was modelled... -
Mesoscale features and phytoplankton biomass at the GoodHope line in the Southern Ocean during austral summer
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: S Swart --- Southern Ocean Carbon and Climate Observatory, South Africa SJ Thomalla --- Southern Ocean Carbon and Climate Observatory, South Africa PMS Monteiro --- Southern Ocean Carbon and Climate Observatory, South Africa IJ Ansorge --- Department of Oceanography, Marine Research Institute, South AfricaTwo sets of high-resolution subsurface hydrographic and underway surface chlorophyll a (Chl a) measurements are used, in conjunction with satellite remotely sensed data, to investigate the upper layer oceanography (mesoscale features and mixed layer depth variability) and phytoplankton biomass at... -
Using chlorophyll fluorescence to determine stress in Eucalyptus grandis seedlings
Item type: Journal Article • Journal: The Southern African Forestry Journal • Authors: Carol A. Rolando --- , Keith M. Little --- ,Since several environmental factors affect the functioning of the photosynthetic system, the status of the photosynthetic apparatus is a good indicator of the plant in terms of stress and stress adaptation. The measurement of chlorophyll fluorescence with a portable fluorimeter... -
Effects of temperature on Pinus patula seedlings growing in pots in a controlled environment
Item type: Journal Article • Journal: The Southern African Forestry Journal • Authors: Colleen A. Carlson --- Horticultural Science Department, South Africa Ross Allan --- Shaw Research Centre, South Africa Andrew R. Morris --- Shaw Research Centre, South AfricaThe re-establishment of Pinus patula seedlings into sites with high harvesting residue (slash) loads can negatively affect the survival of these plants. Field trials have examined the role that insect pests and fungal diseases play in causing this phenomenon. Research... -
Influence of environmental factors on seasonal changes in clupeid catches in the Kigoma area of Lake Tanganyika
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: IA Kimirei YD MgayaAn investigation into the relationship between the fluctuating physico-chemical environment and variability in fish catches in the Kigoma, Tanzania, area of Lake Tanganyika was conducted from January to December 2003. Catch per unit effort (kg fishing unit–1 night–1) showed two... -
Towards the development of environmental indices for the Namibian shelf, with particular reference to fisheries management
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: CH Bartholomae AK van der PlasThe Namibian Ministry of Fisheries and Marine Resources has the task of collecting and providing relevant oceanographic information for management of their fisheries. However, quality information is difficult to provide because of the complexity of the processes involved in the... -
Application of a chlorophyll index derived from satellite data to investigate the variability of phytoplankton in the Benguela ecosystem
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: H Demarcq R Barlow L HutchingsThe spatial and temporal variability in phytoplankton biomass in the Benguela ecosystem was investigated over an 8-year period using a chlorophyll index (Chl Index) derived from low resolution SeaWiFS ocean colour data. Monthly composite images revealed that the surface chlorophyll... -
Primary production in the Benguela ecosystem, 1999–2002
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: R Barlow T Lamont B Mitchell-Innes M Lucas S ThomallaPhytoplankton production was investigated throughout the whole Benguela ecosystem in winter 1999 and in summer 2002 during two four-week research cruises from Cape Town, South Africa, through Namibian waters to Namibe in southern Angola. Primary production ranged from 0.14–2.26 g... -
Effects of leaf and tree age on chlorophyll absorbance in diploid black wattle (Acacia mearnsii)
Item type: Journal Article • Journal: Southern Forests: a Journal of Forest Science • Authors: A Fossey S Mathura SL Beck-PayThe invasiveness of black wattle (Acacia mearnsii) in South Africa has created a need to investigate ways to reduce seed production. The Institute for Commercial Forestry Research is investigating polyploidy production with the view to inducing reduced fertility. Accurate, reliable... -
Spatio-temporal variation in density of microphytoplankton genera in two tropical coral reefs of Mauritius
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: SB Sadally --- Department of Biosciences, Faculty of Science, Mauritius N Taleb-Hossenkhan --- Department of Biosciences, Faculty of Science, Mauritius R Bhagooli --- Department of Biosciences, Faculty of Science, MauritiusSpatial and temporal (seasonal and interannual) variation in microphytoplankton was investigated at two tropical coral reef sites off Mauritius (Belle Mare [BM] and Flic-en-Flac [FEF]), from 2010 to 2012. Each site was divided into three zones: coast, lagoon and reef... -
Water quality monitoring in sub-Saharan African lakes: a review of remote sensing applications
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: T Dube --- School of Agricultural, Earth and Environmental Sciences, South Africa O Mutanga --- School of Agricultural, Earth and Environmental Sciences, South Africa K Seutloali --- School of Agricultural, Earth and Environmental Sciences, South Africa S Adelabu --- Department of Geography, South Africa C Shoko --- School of Bioresources Engineering and Environmental Hydrology, South AfricaWater quality deterioration in sub-Saharan Africa has attained a scale that requires scientific intervention. It is therefore important to devise appropriate and reliable techniques to investigate the water quality of lakes and reservoirs for the development of water resource management... -
Food abundance explains the breeding season of a tropical shorebird, the Crab Plover Dromas ardeola
Item type: Journal Article • Journal: Ostrich: Journal of African Ornithology • Authors: Giuseppe De Marchi --- Dipartimento di Scienze della Terra e dell'Ambiente, Italy Giorgio Chiozzi --- Museo Civico di Storia Naturale, Italy Dawit Semere --- Research Division, Eritrea Yohannes Mebrahtu --- Research Division, Eritrea Farhad Hosseini Tayefeh --- Department of the Environment Provincial Office, Iran Mohammed Almalki --- Department of Biology, College of Science, Kingdom of Saudi Arabia Mauro Fasola --- Dipartimento di Scienze della Terra e dell'Ambiente, ItalyThe timing of breeding in birds is a life-history trait that generally depends on food availability, but other factors may play a role, particularly in tropical areas where food availability is less seasonal than in temperate or polar areas. We... -
Growth, physiology and yield responses of Amaranthus cruentus, Corchorus olitorius and Vigna unguiculata to plant density under drip-irrigated commercial production
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Innocent Maseko --- University of South Africa, South Africa Yacob G Beletse --- Agricultural Research Council–Roodeplaat Vegetable and Ornamental Plant Institute, South Africa Noluyolo Nogemane --- University of South Africa, South Africa CP du Plooy --- Agricultural Research Council–Roodeplaat Vegetable and Ornamental Plant Institute, South Africa Tafadzwanashe Mabhaudhi --- Crop Science, School of Agricultural, Earth and Environmental Sciences, South AfricaAmaranthus cruentus, Corchorus olitorius and Vigna unguiculata are traditional leafy vegetables with potential to improve nutritional security of vulnerable people. The promotion of these crops is partly hindered by the lack of agronomic information. The effect of plant spacing on... -
Effects of short-term water deficit stress on physiological characteristics of Bambara groundnut (Vigna subterranea (L.) Verdc.)
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Yusuf Y Muhammad --- School of Biosciences, Malaysia Sean Mayes --- Plant and Crop Sciences, School of Biosciences, UK Festo Massawe --- School of Biosciences, MalaysiaBambara groundnut (Vigna subterranea (L.) Verdc.) is an annual leguminous food crop native to Africa. The crop is grown in marginal soils and it is considered to be a drought-resistant species. However, there is limited information on the ways Bambara... -
Summer and winter differences in zooplankton biomass, distribution and size composition in the KwaZulu-Natal Bight, South Africa
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: M Pretorius --- University of the Western Cape, South Africa JA Huggett --- Branch: Oceans and Coasts, Department of Environmental Affairs, South Africa MJ Gibbons --- University of the Western Cape, South AfricaZooplankton biomass and distribution in the KwaZulu-Natal Bight were investigated in relation to environmental parameters during summer (January–February 2010) and winter (July–August 2010). Mean zooplankton biomass was significantly higher in winter (17.1 mg dry weight [DW] m–3) than in summer... -
Growth and nutritional qualities of three ocimum species as affected by methods of propagation
Item type: Journal Article • Journal: East African Agricultural and Forestry Journal • Authors: A. I. Okunlola --- Department of Crop, Soil and Pest Management, Nigeria O. C. Ogungbite --- Department of Biology, Nigeria G. F. Hassan --- Department of Crop, Soil and Pest Management, NigeriaOcimum species are well known for their medicinal values and this has increased demand from individuals and the pharmaceutical industry. In order to meet the demand for this plant species three different Ocimum species (Ocimum basilicum, Ocimum gratissimum and Ocimum... -
Photosynthesis versus irradiance relationships in the Atlantic sector of the Southern Ocean
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: S Thomalla --- Ocean Systems and Climate Group, South Africa E Kean --- Biological Sciences Department, South Africa M Lucas --- Biological Sciences Department, South Africa M-J Gibberd --- Biological Sciences Department, South Africa R Barlow --- Department of Oceanography, South AfricaEleven incubation experiments were conducted in the South Atlantic sector of the Southern Ocean to investigate the relationship between new production (ρNO–3), regenerated production (ρNH+4), and total carbon production (ρC) as a function of varying light. The results show substantial... -
Phytoplankton primary productivity seasonality and changes in a small African lake, Lake Hora-Kilole, Ethiopia
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: R Abate --- Aquatic Sciences, Fisheries and Aquaculture Stream, Department of Zoological Sciences, China D Kifle --- Aquatic Sciences, Fisheries and Aquaculture Stream, Department of Zoological Sciences, Ethiopia YH Gao --- School of Life Sciences and State Key Laboratory of Marine Environmental Science, ChinaThe seasonality of primary productivity by phytoplankton in relation to physico-chemical and biological variables was studied in Lake Hora-Kilole from August 2007 to May 2008. In 1989, the Mojo River was temporarily diverted to flow into the lake, which substantially... -
Contrasting hydrography and phytoplankton distribution in the upper layers of cyclonic eddies in the Mozambique Basin and Mozambique Channel
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: T Lamont --- Branch: Oceans and Coasts, Department of Environmental Affairs, South Africa RG Barlow --- Marine Research Institute and Department of Oceanography, South AfricaHydrographic data collected in cyclonic eddies in the Mozambique Channel and Basin revealed notable differences in temperature and salinity at a depth of 100 m, the upper mixed layer, the nitracline depths, and vertical distribution of chlorophyll-a (Chl-a). Differences in... -
Evaluation of satellite retrievals of water quality parameters for Lake Victoria in East Africa
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: A Gidudu --- Department of Geomatics and Land Management, Uganda R Mugo --- Regional Centre for Mapping Resource for Development, Nairobi Kenya L Letaru --- Department of Geomatics and Land Management, Uganda J Wanjohi --- Regional Centre for Mapping Resource for Development, Nairobi Kenya R Nakibule --- Department of Geomatics and Land Management, Uganda E Adams --- Earth System Science Centre–University of Alabama in Huntsville, USA A Flores --- Earth System Science Centre–University of Alabama in Huntsville, USA B Page --- Earth System Science Centre–University of Alabama in Huntsville, USA W Okello --- National Fisheries Resources Research Institute, UgandaLake Victoria in East Africa is a major ecosystem, whose size and importance has warranted the exploration of MODIS imagery to provide continuous and accurate water quality information. To this effect, two sea expeditions (in November 2014 and February 2015)... -
Phenotypical, physiological and biochemical traits of the vegetative growth of wild tepary bean (Phaseolus acutifolius) under restricted water conditions
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Reynaldo Leal-Delgado --- Botánica, Colegio de Postgraduados, México Cecilia B Peña-Valdivia --- Botánica, Colegio de Postgraduados, México Rodolfo García-Nava --- Botánica, Colegio de Postgraduados, México Antonio García-Esteva --- Botánica, Colegio de Postgraduados, México Eleazar Martínez-Barajas --- Departamento de Bioquímica, Facultad de Química, México Daniel Padilla-Chacón --- CONACyT – Colegio de Postgraduados, MéxicoTepary bean (Phaseolus acutifolius A. Gray) is distributed in arid and semi-arid regions from Arizona to the northern areas of Mexico. The objective of this study was to quantify the effects of water deficit on vegetative growth in four accessions... -
Chlorophyll a fluorescence as an indicator of heat stress in cotton (Gossypium hirsutum L.)
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: MM van der Westhuizen --- , South Africa DM Oosterhuis --- , USA JM Berner --- , South Africa N Boogaers --- , South AfricaCotton (Gossypium hirsutum L.) is a major fibre crop that is greatly affected by climatic factors, especially drought and high temperatures. Excessive temperature (above 30 °C) during the reproductive stage (flowering) negatively affects cotton yield potential. Four diverse cotton genotypes... -
Spatial variation of nutrients and primary productivity in the Rufiji Delta mangroves, Tanzania
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: A Minu --- , Tanzania J Routh --- , Sweden JF Machiwa --- , Tanzania S Pamba --- , TanzaniaDeterminations of spatial and temporal variations in organic matter and nutrient dynamics in water and sediments are crucial for understanding changes in aquatic bodies. In this study, we (i) determine the spatial dynamics of dissolved inorganic nutrients, during the transition... -
Growth and yield of African ginger in response to application of organic fertiliser
Item type: Journal Article • Journal: South African Journal of Plant and Soil • Authors: Phomolo Maphothoma --- , Riana Kleynhans --- , Gerhard Prinsloo --- , Salmina N Mokgehle --- , Ian du Plooy --- , Hintsa T Araya --- ,African ginger (Siphonochilus aethiopicus) is in high demand for medicinal use. The plant does not multiply after being harvested, as it is destroyed in the process. The species is now facing extinction as a result of over harvesting. In order... -
Is the largest African penguin colony in South Africa influencing local ocean productivity?
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: G Passuni --- , South Africa LRD Human --- , South Africa SN Riddick --- , United States P Pattrick --- , South Africa M Bizani --- , South Africa SHP Deyzel --- , South Africa NA Strydom --- , South Africa TG Bornman --- , South Africa L Pichegru --- , South AfricaIn coastal waters, nutrient supplies originate principally from allochthonous sources, such as inputs from rivers, estuaries or oceanic waters. Recently, it has been suggested that marine life contributes to the nutrient load, with penguin colonies being the largest contributor worldwide... -
The ecology of coastal wetland ponds created by diamond mining in southern Namibia. 1. Physical conditions
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: L Maritz --- , South Africa D Pillay --- , South Africa GM Branch --- , South AfricaCoastal diamond mining in southern Namibia involves constructing seawalls to hold the sea at bay, and seaward accretion of the shoreline by up to 800 m opens what was previously the surf zone for excavation and extraction of bedrock alluvial... -
Rainfall-driven nutrient loading affects coastal phytoplankton in the southwestern Indian Ocean: a lagoon at Mauritius Island
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: M Soondur --- , Republic of Mauritius R Boojhawon --- , Republic of Mauritius R Lowe --- , Australia D Kaullysing --- , Republic of Mauritius BE Casareto --- , Japan Y Suzuki --- , Japan R Bhagooli --- , Republic of MauritiusThis study aimed to test the effects of rainfall-driven nutrient loading on the microphytoplankton dynamics in the shallow water at Trou aux Biches lagoon on the northwest coast of Mauritius. Changes in density, diversity and estimated productivity of microphytoplankton were... -
Limnological features and water-quality changes of two Ethiopian Rift Valley lakes, Lake Abaya and Lake Chamo
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: A Dagne --- National Fishery and Aquatic Life Research Center, Ethiopia H Tadesse --- National Fishery and Aquatic Life Research Center, Ethiopia K Teshome --- National Fishery and Aquatic Life Research Center, EthiopiaWe conducted a study in Lake Abaya and Lake Chamo, the two largest Ethiopian Rift Valley lakes, between 2016 and 2019, to evaluate their limnological features and infer longer-term changes in some water-quality parameters. Data generated through in situ measurements...