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UNDERSTANDING THE PHYSICAL STRUCTURE OF SOUTHERN AFRICA'S STANDING WATERS
Item type: Journal Article • Journal: Journal of the Limnological Society of Southern Africa • Authors: B.R. Allanson --- , South AfricaAn examination of the nature of the stratification in polymictic and monomictic Southern African reservoirs is presented. Wind stirring is the principal mode of heat transfer during spring heating. In high summer radiation from stable heated surface layers is responsible... -
THE DIURNAL MIXED LAYER IN LAKES AND OCEANS
Item type: Journal Article • Journal: Southern African Journal of Aquatic Sciences • Authors: JohnL. Largier --- Division of Earth, Marine and Atmospheric Science and Technology, South AfricaIn this review the current ideas on diurnal mixed layers are discussed with reference to several observations. Essentially, solar heating sets up a shallow thermocline which traps and concentrates further influx of heat and momentum in the top few metres... -
The Evolution of Thermohaline Structure in a Closed Estuary
Item type: Journal Article • Journal: Southern African Journal of Aquatic Sciences • Authors: J.H. Slinger --- , South Africa J.L. Largier --- , U.S.A.Following the closure of the mouth of the Palmiet estuary in February 1988, the thermohaline structure was recorded at approximate weekly intervals. The evolution of the two-layer structure was studied and the mixing processes causing the changes were determined. Vertical... -
A CHARACTERIZATION OF SOUTHERN AFRICAN ESTUARINE SYSTEMS
Item type: Journal Article • Journal: Southern African Journal of Aquatic Sciences • Authors: A.K. Whitfield --- , South AfricaModifications to the structure and functioning of southern African estuarine systems can be placed into two major categories; those changes that have been driven by global forces such as climatic and sea-level fluctuations, and those that have resulted from direct... -
Seasonal and diurnal stratification in two small Zimbabwean reservoirs
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: Tamuka Nhiwatiwa BrianE MarshallSeasonal and diurnal stratification patterns were studied in two small Zimbabwe reservoirs. The water level of the upper reservoir fluctuated more than that of the lower one and theoretical water retention times were 9 days and 3.6 days, respectively. Rainfall... -
Buoyancy-stirring interactions in a subtropical embayment: a synthesis of measurements and model simulations in Maputo Bay, Mozambique
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: JD Lencart e Silva --- , UK JH Simpson --- , UK AM Hoguane --- School of Marine and Coastal Sciences, Mozambique J-L Harcourt-Baldwin --- Department of Oceanography, South AfricaMaputo Bay, on the coast of Mozambique, is a tidally energetic, subtropical embayment in a region subjected to strong seasonal rainfall. Data from moored current meters, tide gauges and monthly bay-wide surveys were used to characterise the evolution of the... -
Potassium maldistribution revisited
Item type: Journal Article • Journal: Southern African Journal of Anaesthesia and Analgesia • Authors: Justine Pietersen --- Department of Anaesthesiology and Critical Care, South Africa Andrew Levin --- Department of Anaesthesiology and Critical Care, South AfricaObjective: This study investigated the maldistribution of concentrated 15% potassium chloride after injection into one-litre, flexible, Ringer’s lactate bags. -
Assessing the South African sardine resource: two stocks rather than one?
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: CL de Moor --- Marine Resource Assessment and Management Group (MARAM), Department of Mathematics and Applied Mathematics, South Africa DS Butterworth --- Marine Resource Assessment and Management Group (MARAM), Department of Mathematics and Applied Mathematics, South AfricaSardine Sardinops sagax distributed off the west and south coasts of South Africa have traditionally been assumed to comprise a single well-mixed stock for assessment and management purposes. New research, however, lends weight to the possibility of two stocks in... -
Using stable isotope analysis to study the diet of Gilchristella aestuaria larvae: preliminary insights into the foodwebs of six South African estuaries
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: D Costalago --- Department of Ecology, Environment and Plant Sciences, Sweden NAF Miranda --- DST/NRF Research Chair in Shallow Water Ecosystems, Department of Zoology, South Africa NA Strydom --- Department of Zoology, South Africa R Perissinotto --- DST/NRF Research Chair in Shallow Water Ecosystems, Department of Zoology, South AfricaSouth African estuarine systems are becoming increasingly altered by anthropogenic and environmental factors, but the consequences of such changes for these systems are still not fully understood. The most common approach for evaluating the ecological status of aquatic systems is... -
Temporal dynamics and relationship between climate, limnological variables and zooplankton composition in climate-sensitive Lake Bosumtwi, Ghana
Item type: Journal Article • Journal: African Journal of Aquatic Science • Authors: PO Sanful --- Department of Fisheries and Water Resources, School of Natural Resources, Ghana S Aikins --- Department of Theoretical and Applied Biology, Ghana E Frempong --- Department of Theoretical and Applied Biology, Ghana RI Hall --- Department of Biology, Canada RE Hecky --- Biology Department and Large Lakes Observatory, USAThe community composition and the factors affecting seasonal and interannual dynamics of zooplankton in Lake Bosumtwi were studied biweekly at a central index station during 2005 and 2006. The lake zooplankton community was species poor. Mesocyclops bosumtwii was numerically superior... -
Ecology and behaviour of Palm-nut Vultures Gypohierax angolensis in the Bijagós Archipelago, Guinea-Bissau
Item type: Journal Article • Journal: Ostrich: Journal of African Ornithology • Authors: Camilo Carneiro --- Department of Biology and CESAM, Portugal Mohamed Henriques --- Faculty of Sciences, Portugal Castro Barbosa --- Institute of Biodiversity and Protected Areas of Guinea-Bissau, Guinea-Bissau Quintino Tchantchalam --- Institute of Biodiversity and Protected Areas of Guinea-Bissau, Guinea-Bissau Aissa Regalla --- Institute of Biodiversity and Protected Areas of Guinea-Bissau, Guinea-Bissau Ana R Patrício --- Centre for Ecology and Conservation, UK Paulo Catry --- MARE – Marine and Environmental Sciences Centre, PortugalPopulations of many vulture species have undergone substantial declines. In Africa, 82% are threatened and although research on vultures has increased, the biology and ecology of several species is still poorly known. The Palm-nut Vulture Gypohierax angolensis has peculiar ecological... -
Using stable δ13C and δ15N isotopes to assess foodweb structures in an African subtropical temporary pool
Item type: Journal Article • Journal: African Zoology • Authors: L de Necker --- Water Research Group, Unit for Environmental Sciences and Management, South Africa A Manfrin --- Environmental Campus Birkenfeld, Germany Y Ikenaka --- Water Research Group, Unit for Environmental Sciences and Management, South Africa M Ishizuka --- Laboratory of Toxicology, Department of Environmental Veterinary Sciences, Graduate School of Veterinary Medicine, Japan L Brendonck --- Water Research Group, Unit for Environmental Sciences and Management, South Africa JHJ van Vuren --- Water Research Group, Unit for Environmental Sciences and Management, South Africa B Sures --- Department of Aquatic Ecology and Centre for Water and Environmental Research (ZWU), Germany V Wepener --- Water Research Group, Unit for Environmental Sciences and Management, South Africa NJ Smit --- Water Research Group, Unit for Environmental Sciences and Management, South AfricaSouthern Africa has one of the highest densities of temporary pools and some of the most understudied temporary wetlands in the world. Additionally, the eastern African annual killifishes (Nothobranchius spp.) are rare in southern Africa and found exclusively in temporary... -
Partitioning the sources of sediment organic carbon in South African seagrass meadows
Item type: Journal Article • Journal: African Journal of Marine Science • Authors: A Bossert --- Stellenbosch University, South Africa S von der Heyden --- Stellenbosch University, South Africa J Colling --- Stellenbosch University, South Africa A Ndhlovu --- Stellenbosch University, South AfricaIn the sediments of seagrass meadows, allochthonous carbon sources can account for 50–90% of sediment organic carbon (SOC), in which non-seagrass carbon is derived from external organic matter advected into the meadow’s sediments or trapped by the seagrass canopy. Identifying...