Potential Application of Adsorptive Media to Enhance Phosphorus Uptake in Stormwater Basins and Wetlands at Lake Tahoe : literature review. Report to the University of California Davis Tahoe Research Group

Phosphorus removal by wetlands and basins in Lake Tahoe may be improved through designing these systems to filter storm water through media having higher phosphorus removal capabilities than local parent material. Substrates rich in iron, aluminum and calcium oftentimes have enhanced phosphorus removal. These substrates can be naturally occurring, byproducts of industrial or water treatment processes, or engineered. Phosphorus removal fundamentally occurs through chemical adsorption and/or precipitation and much of the phosphorus can be irreversibly bound. In addition to these standard media, other engineered substrates are available to enhance P removal. One such substrate is locally available in Reno and uses lanthanum coated diatomaceous earth for arsenate removal. This material, which has a high positive surface charge, can also irreversibly remove phosphorus. Physical factors also affect P removal. Specifically, specific surface area and particle shape affect filtration capacity, contact area between water and the surface area, and likelihood of clogging and blinding. A number of substrates have been shown to effectively remove P in case studies. Based upon these studies, promising substrates include WTRs, blast furnace slag, steel furnace slag, OPC, calcite, marble Utelite and other LWAs, zeolite and shale. However, other nonperformance factors such as environmental considerations, application logistics, costs, and potential for cementification narrow the list of possible media for application at Tahoe. Industrial byproducts such as slags risk possible leaching of heavy metals and this potential cannot be easily predicted. Fly ash and other fine particle substrates would be more difficult to apply because they would need to be blended, making them less desirable and more costly to apply than larger diameter media. High transportation costs rule out non-local products. Finally, amorphous calcium products will eventually cementify reducing their effectiveness in filtration systems. Based upon these considerations, bauxite, LWAs and expanded shales/clays, iron-rich sands, activated alumina, marble and dolomite, and natural and lanthanum activated diatomaceous earth are the products most likely to be tested for application at Tahoe. These materials are typically iron, calcium or aluminum based; many have a high specific surface area; and all have low transportation costs. (PDF contains 21 pages)

Growth response and survival of F1 hybrid fry of Heterobranchus longifilis and Clarias gariepinus reared in glass aquaria and plastic basins

The growth response of F1 hybrid fry of female Heterobranchus longifilis and male Clarias gariepinus were investigated under laboratory conditions in glass aquaria glass tanks and plastic basins. The larvae were produced artificially after inducement with Ovarptim. The hatching percentage was very high. Weekly mean length and weight were monitored for 6 weeks. The average length increase was higher in aquaria glass tanks than in plastic basins. However, there were depressed and irregular weight increases in both types of rearing troughs while significant weight increase (P<0.05) was recorded at week 6 in the plastic basin. Generally, the growth rate and survival in both containers were not significantly different

Studies of chemical speciation in naturally anoxic basins

The chemical speciation of both metals and non-metals, the use of polarographic techniques, and application to the study of the chemistry of anoxic waters are considered. In the first part of the paper unfamiliar terminology is explained and then an example of simple lake chemistry is presented to illustrate why the concept of speciation is necessary.

Co-oscillation of a fjord basin’s circulation with decade-long oceanographic, hydrologic, and climatic regimes: Puget Sound 1916-'87 [abstract]

EXTRACT (SEE PDF FOR FULL ABSTRACT): Oceanographic, hydrologic, and climatic data collected during 1916-'87 in Puget Sound's Main Basin (~200 m x 5 km x 100 km) and approaches oscillate at low frequency between two regimes (I, II). The oscillation accounts for a large fraction of the interannual variability (41-75%) and the zero crossings between regimes span approximately a decade. ... The transition between regimes is accompanied by substantial changes in the horizontal pressure and density fields between the Pacific coast and the mixing zones leading to the Basin, as well as within the Basin itself.

The major aquatic systems of the Victoria and Kyoga lake basins

The Victoria and Kyoga lake basins form the major aquatic system of this study (Fig. I). The two lake basins share a common evolutionary history and have similar native fish faunas (Graham 1929, Worthington 1929). The two main lakes have also had similar impacts by introduction of Nile perch Lates niloticus and therefore these two lakes can be considered to be similar for ichiogeographical purposes. These lake basins have many satellite lakes isolated from one another and from the main lakes Victoria and Kyoga by swamps and other barriers. Some of these satellite lakes still possess stocks of endemic fish species which are almost extinct from the main water bodies. It was therefore considered that understanding of these lakes would contribute to the knowledge base required to solve some of the problems experienced in Lake Victoria and Kyoga especially the loss in trophic diversity arising. The study was carried out in these two main water bodies (Kyoga and Victoria) and on other satellite lakes e.g Wamala, Kachera, Mburo, Kayanja and Kayugi in the Victoria lake basin and lakes Nawampasa, Nyaguo, Agu, Gigate, Lemwa and Kawi in the Kyoga lake basin (Figs. 2, 3, 4, 5 & 6).

Physical and chemical characteristics of major aquatic ecosystems in the Victoria and Kyoga lake basins

The physical-chemical characteristics of any aquatic ecosystem include pH, conductivity, and temperature, water transparency, nutrient and the chlorophyll-a levels. Physical and chemical factors of any ecosystem determine the type and quality of flora present in it and these forms the basis on which the system operates. The elements required in largest amounts for plant productions are carbon, phosphorus, nitrogen, and silicon, which is important for diatoms as a major component of the cell wall. Nutrients may limit algal productivity in the tropics despite the high temperature there allowing rapid nutrient recycling. Nutrients most likely to be limiting African lakes are nitrogen (Talling & Talling 1965; Moss 1969; Lehman & Branstrator 1993, 1994) and phosphorus (Melack.et al l982; Kalff 1983) while silicon may limit diatom growth (Hecky & Kilham 1988). The objective of the study is to investigate the impact of physical-chemical characteristics on the distribution and abundance of organisms in the major aquatic ecosystems.

The diversity of aquatic flora and their importance in the Victoria and Kyoga lake basins

A great part of Uganda is endowed with water bodies in the forms of rivers and open water lakes. These bodies are never alone. They are either flanked or associated with plants, which are adapted to the wet conditions. They are so characteristic that they are part and parcel of the aquatic ecosystems. They occupy various positions depending on the amount of water in the relevant habitats.

The diversity and abundance of zooplankton in the Lake Victoria and Kyoga basins and their relationship to fish production

Biological diversity of an ecosystem is considered a reliable measure of the state of health of the ecosystem. In Uganda's large lakes, the Victoria and Kyoga, the past three decades have been characterized by profound changes in fish species composition following the introduction of the piscivorous Nile perch (Oguto-Ohwayo 1990). Over 300 haplochromine cichlid species comprising a wide range of trophic groups were lost along with a host of non-cichlid fishes which occupied virtually all available ecological niches and in the lakes (Witte 1992). A second major ecological event has been the gradual nutrient enrichment of the water bodies (eutrophication) from diffuse and point sources, while at the same time pollutants have also gained entrance into the water systems in pace with indusfrial development and human population increases in the lake basins. Eutrophication and pollution have drastically altered the physical and-chemical character of the water medium in which different fauna and flora thrive. In Lake Victoria these alterations have resulted in changes of algal species composition from pristine community dominated by chlorophytes and diatoms (Melosira etc) to one composed largely of blue-green algae or Cyanobacteria (Microcystis, Anabaena, Planktolyngbya etc) (Mugidde 1993, Hecky 1993).

Fish species diversity in the Victoria and Kyoga lake basins: their conservation and sustainable use

Introduction of exotic fish species especially the Nile perch Lates niloticus, is believed to be responsible for the decline of fish species diversity in lakes Victoria, Kyoga and Nabugabo.About 60% of the haplochromine cichlids are thought to have become extinct from L. Victoria due to predation by the Nile perch. However there are many lakes satelite to the lakes Victoria and Kyoga basins which still have fish fauna similar to that of the main lakes. many of the satellite lakes are separated from the main lakes in, which Nile perch was introduced by extensive swamps that provide a barrier to Nile perch .A survey was carried out in a number of these satelite lakes and an inventory made of existing fish species. Their distribution and relative abundances were also determined. The lakes studied included Nawampasa, Nakuwa,Kawi Lamwa Gigate, Nyaguo, Agu, Nabugabo. Kayanja, Kaytigi, Mburo, Kachera and Wamala.Some habitats within the main lakes Victoria and Kyoga, especially those with rocky outcrops· and macrophyte cover that provide refugia for endangered species from Nile perch,were also surveyed) Various stations along the River Nile were also sampled to quantify the fish species that are still resent. Kyoga minor lakes were found to have the highest number of fish species especially of haplochromine cichlids. Many haplochromine trophic groups that were thought to be extinct from 1. Victoria still occur in these lakes.!Some of the satellite lakes, especially lakes Kayugi, Mburo and Kachera still contain .healili populations of oreochromis. I esculentus that could be used as brood stock in fish farming. Many of these lakes should .I ( I therefore be protected for conservation offish species diversity

The diversity of amphibians, reptiles and mammals and their importance in the Victoria and Kyoga lake basins

The shore margins of Lakes in the Victoria basin are highly dented and mostly swampy, fringed by Papyrus and other wetland vegetation types important habitats for herpetofauna and wetland adapted mammals. Of recent, the extent of the 'wetland' has been extended in several places by the Water Hyacinth (Eichornia cryaseps). Ecologically, amphibians are important in many ways; they are mostly predators, acting as primary and secondary carnivores. Their prey consists mostly of insects, some of which are pests to crops or disease vectors. They are also inter-inked in food chains, often acting as food for other vertebrates, such as pigs, birds, snakes and sometimes man. Because of their ectothermic physiology, the life history and ecology of amphibians often differ markedly from that of birds or mammals (McCollough el ai, (992).Amphibians are known to be an easily recognisable taxon in given habitats; and populations are sometimes specialised within a narrow habitat. This makes it easy and practical to monitor changes in composition over time, given different onditions (Heyer el al 1994, Phillips 1990). Impacts on their habitat are reflected in changes in numbers and species diversity in a short time. These are some of the factors that have made amphibians to be recognised, nowadays, as good indicators of habitat change

Genetic status of selected fish taxa in relation to conservation of genetic and species diversity in the Victoria and Kyoga Lake basins

Cichlids are known for their explosive radiation especially in the African Great Lakes marked with a high level of lake endemism. These fishes have been characterized mainly along trophic and habitat differences, by variation in morphological structures such as teeth and jaws and by differences in body shape and coloration. Cichlids are important as a microcosm of macroevolution. The explosive radiation, young evolutionary scale, and the isolation of groups characterized with high levels of endemism and presence of living fossils makes the group important for evolutionary and genetic studies. Lake Victoria region cichlids which are isolated and relatively more recent in evolution were the last to be appreciated in their diversity. Recently Ole Seehausen has found scores of rock fishes in Lake Victoria which were up to then thought to be absent from the Lake and only known to occur in Lakes Malawi and Tanganyika. Greenwood put together the species groups of Lake Victoria, and later in the early 1980's revised the classification of haplochromine species to reflect the phyletic origin and interrelationship of the various groups in Lake Victoria region. Melan Stiassny has been interested in early evolution of cichlids while the likes of Paul Fuerst and Lees Kaufman and Axel Meyer have been interested and are working to explain the speciation mechanisms responsible for the explosive radiation and evolution of cichlids. Locally S.B Wandera and his student Getrude Narnulemo are spearheading the biodiversity and taxonomic studies of cichlids in Lake Victoria region