ALBERT

Description: © The Author(s), 2019. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Millette, N. C., Kelble, C., Linhoss, A., Ashby, S., & Visser, L. Using spatial variability in the rate of change of chlorophyll a to improve water quality management in a subtropical oligotrophic estuary. Estuaries and Coasts, 42(7), (2019): 1792-1803, doi:10.1007/s12237-019-00610-5.

Description: Anthropogenic eutrophication threatens numerous aquatic ecosystems across the globe. Proactive management that prevents a system from becoming eutrophied is more effective and cheaper than restoring a eutrophic system, but detecting early warning signs and problematic nutrient sources in a relatively healthy system can be difficult. The goal of this study was to investigate if rates of change in chlorophyll a and nutrient concentrations at individual stations can be used to identify specific areas that need to be targeted for management. Biscayne Bay is a coastal embayment in southeast Florida with primarily adequate water quality that has experienced rapid human population growth over the last century. Water quality data collected at 48 stations throughout Biscayne Bay over a 20-year period (1995–2014) were examined to identify any water quality trends associated with eutrophication. Chlorophyll a and phosphate concentrations have increased throughout Biscayne Bay, which is a primary indicator of eutrophication. Moreover, chlorophyll a concentrations throughout the northern area, where circulation is restricted, and in nearshore areas of central Biscayne Bay are increasing at a higher rate compared to the rest of the Bay. This suggests increases in chlorophyll a are due to local nutrient sources from the watershed. These areas are also where recent seagrass die-offs have occurred, suggesting an urgent need for management intervention. This is in contrast with the state of Florida listing of Biscayne Bay as a medium priority impaired body of water.

Description: Data provided by the SERC-FIU/SFWMD Water Quality Monitoring Network is supported by SFWMD/SERC Cooperative Agreement #4600000352 as well as EPA Agreement #X7-96410603-3. This research was also funded by a NOAA/Atlantic Oceanographic and Meteorological Laboratory grant to the Northern Gulf Institute (award number NA160AR4320199).

Description: In the following we present a new non-invasive methodology aimed at the diagnosis of stone building materials used in historical buildings and architectural elements. This methodology consists of the integrated sequential application of in situ proximal sensing methodologies such as the 3D Terrestrial Laser Scanner for the 3D modelling of investigated objects together with laboratory and in situ non-invasive multi-techniques acoustic data, preceded by an accurate petrographical study of the investigated stone materials by optical and scanning electron microscopy. The increasing necessity to integrate different types of techniques in the safeguard of the Cultural Heritage is the result of the following two interdependent factors: 1) The diagnostic process on the building stone materials of monuments is increasingly focused on difficult targets in critical situations. In these cases, the diagnosis using only one type of non-invasive technique may not be sufficient to investigate the conservation status of the stone materials of the superficial and inner parts of the studied structures 2) Recent technological and scientific developments in the field of non-invasive diagnostic techniques for different types of materials favors and supports the acquisition, processing and interpretation of huge multidisciplinary datasets.

Description: Regione Autonoma della Sardegna (RAS) (Sardinian Autonomous Region), Regional Law 7th August 2007, no. 7, Promotion of scientific research and technological innovation in Sardinia (Italy).

Description: Published

Description: 4334

Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica

Description: JCR Journal

Description: The main objective of the study was to generate information on the levels of pesticide residue levels in soil, sediments and water from river Nyando catchment area, where various pesticides are used for agricultural production. The data generated will form the basis for future surveillance program on pesticides residues within the Lake Victoria catchment area and in policy formulation on the level of POPS in the environment .

Description: Published

Description: In this study, meteorological and hydrodynamic data were collected using automated instruments. Meteorological conditions data were logged at 1-hour intervals at the shoreline land station of Yala Swamp. A pressure sensor installed at Kisumu pier recorded lake level data at 2-hour intervals. Lake conditions were sampled in Winam Gulf, Rusinga Channel and Lake Victoria on nineteen cruises from December 2000 to March 2005. Water column currents, temperature, oxygen, pH and conductivity parameters measurements were conducted longitudinally and across transects along Rusinga Channel, Winam Gulf and Lake Victoria. Results of the analysis of diel and seasonal changes in meteorological conditions and the resulting thermal stratification and water circulation patterns are reported here and compared with previous findings on Lake Victoria. A brief historical perspective of the annual thermal cycle of stratification of pelagic waters of Lake Victoria is given.

Description: Published

Description: The need to carry out sedimentation and sediment characteristics study at the river mouths and the lake was contingent upon the supposition that the rivers in the lake Victoria catchment including surface runoffs convey a great deal of assorted sediments, most of which are deposited in the lake thereby causing the lake to continue filling up and affecting the quality of water.

Description: Published

Description: The main purpose of the Study was to review the relationship between water quality and human health in the Lake region and the effects that various mitigation measures may have. This was to help make future projects to be more focused towards the main goal of improved standard of living for the inhabitants in the study area, through improved human health conditions. This report contains findings and analysis from Kenya from the study on Water Quality & Human Health around Lake Victoria.

Description: Published

Description: One of the principal objectives of the Water Quality and Ecosystem Management Components is to find the reasons for the changes observed in the lake water quality and quantity in order to establish causes of change in the lake ecosystem and to identify remedial measures. To identify the reasons for the changes one requires a knowledge of the changes in the pollution loadings to the lake, which, in turn, depends on the discharges into the lake from the catchments and the atmosphere and the outflow to River Nile i.e. hydrology and meteorological characteristics in and around the lake. Hydro-metrological data for the period running 1950-2004 were analysed and form the basis for computing the pollution loadings (catchment and atmospheric) into the lake and as well as calculation of the lake water balance. Continuous rainfall and evaporation records were applied and data gaps filled were necessary. Full records of land discharges were obtained from rainfall records using the NAM model. Model performance was evaluated on the ability to simulate the total flow rather for catchments, rather than the peak and minimum flows, for pollution estimation. Results indicate that Tanzania’s land unshared catchment annual discharge contribution to Lake Victoria is approximately 5,430 BCM1, while Uganda’s one is approximately 1,062 BCM and Kenya’s is approximately 9,271 BCM which in percentage are 21.4%, 4.2% and 37% respectively. Rivers Mara and Kagera that are shared between Kenya and Tanzania and Tanzania, Rwanda, Burundi and Uganda respectively had total flows of 1,151 BCM and 8,215 BCM accordingly representing 4.6% and 32.7% of the total catchment discharges. The mean annual rainfall over the Ugandan side of the lake is about 62,539 BCM, Tanzania is about 60,682 BCM and Kenya is about 4,541 BCM. These constitute 48.9%, 47.5%, and 3.6% respectively of the total mean annual lake rainfall into Lake Victoria. There was a 10.7% decrease in rainfall over the Lake in the period 1972-1993. However in the period 1994-2004 there was a 2.2% increase in the amount However there was a 14.7% decrease in catchment inflows into the lake and a 1.64m drop in water level in the period 1998- 2004.

Description: Published

Description: This study reports of the results of extensive field monitoring of river flows and lake levels, rainfall and evaporation. The study’s aim was to elucidate main trends and periods of meteorology and hydrology as revealed by time series of rainfall, evaporation, river discharge and lake levels and which could be used as input towards computation of nutrient and sediment load introduced into Lake Victoria. Hydro-metrological data for the period running 1950-2004 were analysed and form the basis for computing the pollution loadings (catchment and atmospheric) into the lake and as well as calculation of the lake water balance. Continuous rainfall and evaporation records were applied and data gaps filled were necessary. Full records of land discharges were obtained from rainfall records using the NAM model. Model performance was evaluated on the ability to simulate the total flow for catchments, rather than the peak and minimum flows, for pollution estimation. The implication of the results in the eutrophication related processes in the lake are also discussed in this report.

Description: Published

Description: The Water Quality and Ecosystem Management Components of the Lake Victoria Environmental Management Project (LVEMP) in the three East African countries collaborating on LVEMP phase 1 have made considerable progress towards understanding Lake Victoria water quality and its ecosystem as well as effects of resource utilization and exploitation on the lake and its catchment.

Description: Published

Description: Water quality monitoring activities were carried out on physical-chemical parameters, water chemistry and biotic indices at selected littoral and pelagic stations along north-south and east-west transects over an annual cycle between 2000 and 2005. The activities were aimed at collecting baseline information and data for use to define the current lake conditions and make a water quality assessment of the lake in relation to nutrient/ pollutant loadings as a basis for future monitoring surveys. As much as possible current conditions of the lake were compared to past observations where field sites coincided with those of historical studies. Littoral stations (0-20m) showed higher temperatures, pH, turbidities and electrical conductivity while Secchi depths and dissolved oxygen were lower compared to pelagic ones. Deeper pelagic sites experience thermal stratification, leading to strong differences between surface and deep water layers especially in terms of temperature and dissolved oxygen except for June through August during which the lake achieves complete mixing in all stations. On average, littoral stations have higher total nitrogen, chlorophyll, organic matter as well as total particulate carbon. Phytoplankton production and biomass in shallow inshore sites is light-limited due to self shading and the latter can therefore sustain higher algal biomasses because of limited mixing depths. Nitrogen often limits algal growth except for Cyanobacteria that can fix atmospheric nitrogen to meet their N limitations. The higher algal biomass accounts for the higher TN concentrations, chlorophyll and organic matter at littoral sites. During thermal stratification, TP and SRP concentrations are comparable in littoral and pelagic sites while during and just after mixing, both fractions of P are higher in the littoral areas. Continuous excess SRP and the ability of Cyanobacteria to fix atmospheric nitrogen create nutrient saturated conditions that result in light limitation for algal growth. Annual rainfall is characterised by two peaks in the stratification seasons 2 and 3 and appears to be the main source of nutrient enrichment in the lake, particularly TP. Decomposition of organic matter during the stratification period results into release of TP and Si into deeper waters where they build up to much greater concentration than in surface waters. TN reaches annual minimum during the deep mixing period because of N-poor deep waters. Chlorophyll concentrations also reach their annual minimum at this time as deep mixing imposes strong light limitation on algal growth and nitrogen fixation especially in pelagic areas. Comparisons with historical records show that the lake today is warmer than in the 1960s but with lower oxygen and pH in the deeper waters. Thus deep water respiration rates, oxygen consumption and CO2 are higher in the 2000s largely attributed to the eutrophication of the lake. Oxygen depletion in deeper waters during thermal stratification has led to loss of habitat for fish and other biota. Chlorophyll levels, phosphorus concentrations and electrical conductivity in both littoral and pelagic stations have increased compared to records of the 1960s. On the other hand nitrogen concentrations around marginal bays and gulfs have not shown a marked increase compared to historical records of the 1960s and 1970s. Dissolved silicon in the pelagic areas has decreased 5-20 times compared to historical records as eutrophication has increased Si demand by diatoms relative to rather constant supply from the catchment. In line with increased algal turbidities, Secchi depths have decreased at least two-fold since the 1960s. The need for lake wide regular water quality surveys and basin developments in support of appropriate management interventions can not be overemphasized at present in order to determine whether the lake is continuing along the same trends over time documented in this report.

Description: Published

Description: The objectives of the Lake Victoria environment monitoring were to obtain data for: (1) Determination of the present state of the lake water quality and ecosystem. (2) Analysis of the relative importance of the biological processes and limiting factors in the eutrophication of the lake. (3) Calibration of the Lake Victoria Water Quality Framework Model. (4) Long -term monitoring of changes taking place in the lake. To achieve these objectives a programme for monthly lake monitoring on the lake was established to gather data on the quality of the waters of the lake and the lake’s limnology through in-situ measurements, and laboratory analysis of samples.

Description: Published

Description: This paper reports on the major limnological and water quality findings in Lake Victoria, Kenya and offers suggestions on sustainable management of lake water quality.

Description: Published

Description: The Lake Victoria Basin (LVB) has become a focal point of development in Kenya, thereby attracting intensive multiple land use which has accelerated environmental degradation through siltation, water pollution and changes in flooding frequency. In addition, multi-sectoral uses of water have created competition among various water users without due regard to the need for ecological sustenance or the needs of downstream users. This pattern poses serious management problems. The LVB is used as a source of food, energy, drinking and irrigation water, shelter, transport and as a repository for human, agricultural and industrial waste. With the population of the riparian communities growing at rates among the highest in the world, the multiple activities in the lake basin have increasingly come into conflict. This has contributed to rendering the lake environmentally unstable. The lake ecosystem has undergone substantial, and to some observers alarming changes, which have accelerated over the last three decades. Massive blooms of algae have developed, and come increasingly to be dominated by the potentially toxic blue-green variety. The distance at which a white disc is visible from the surface, (a transparency index measuring algal abundance or secchi depth), has declined from 5 m in the early 1930s to 1 m or less for most of the year in the early 2000s. Water-borne diseases have increased in frequency. Water hyacinth, absent as late as 1989, has choked important waterways and landings. Overfishing and oxygen depletion at lower depths of the lake threaten the artisanal fisheries and biodiversity (over 200 indigenous species are believed to be facing possible extinction). Scientists advance two main hypotheses for these extensive changes. First, the introduction of the Nile perch as an exotic species some 30 years ago has altered the food web structure; second, nutrient inputs from the adjoining catchments are causing eutrophication. Thus, although the lake and its fishery show the evidence of the dramatic changes in the lake basin over the past century, the lake is not the source of the problem. The problem has arisen in the surrounding basins through polluting activities of humans activity and the demand for fish.

Description: Published

Description: Concern has been raised about the contribution of atmospheric deposition to the nutrient flux of Lake Victoria. A few studies on the atmospheric deposition over the African Great Lakes have shown that the atmospheric deposition is a significant source of Total Nitrogen (TN) and Total Phosphorus (TP) to lakes and in fact by far the highest contributor of N and P on the lake surface. This has been attributed to the large scale destruction of soil cover as a result of changes in the land use system, improper agricultural practices and transport from other regions through regional and global air circulation. The objective of this study was to estimate the amount of TP and TN coming from the atmosphere and to compliment measurement from the catchment in order to estimate a nutrient mass balance for Winam Gulf. Two stations were selected for this study, Kadenge and Kisumu. Both wet and dry atmospheric samples were collected in an acid rinsed bucket mounted on a metal structure 1.5m from the ground and analysed for TP and TN using standard methods. It was observed that the annual dry deposition rates for both TP and TN were higher than the wet ones. Dry TP. 575.2 tonnes/year, wet TP. 472.8 tonnes/year giving a total of 1048 tonnes/year with dry P accounting for 55% and wet P 45%. Dry TN. 10289.98 tonnes/year, wet TN. 12133.6 tonnes/year and a total of 22423.6 tonnes/year and dry N accounting for 46% and wet N 54 %. Compared with estimates of TP and TN from the catchment studies these represent about 38% TP and about 70% TN to the Winam Gulf (Kenyan side of L.Victoria) If these rates are applied to the whole lake surface assuming that there is no major difference in deposition rates across the lake, it was estimated that 17515.5 tonnes of TP and 373727.2 tonnes of TN was deposited per year with dry P accounting for more than 50% of TP and dry N accounts for more than 50% of TN. These estimates have been made from two land-based stations and therefore there is need for the inshore stations to be established. It is therefore necessary as a management strategy to eutrophication in Lake Victoria, to address the atmospheric deposition alongside other sources of nutrients to the lake.

Description: Published

Description: Training programs were designed to provide scientists with strengths in applied limnology, monitoring and the environment. In addition, the training provided scientists with a firm background in data analysis, interpretation and synthesis procedures, including statistics, numerical analysis, programming and conceptual modelling methods. Most hydrologists and water chemists in public and private employment were educated in a tradition that emphasized qualitative schooling, and this project therefore has managed to train a new type of scientist who can apply calculations to their research, monitoring or operational undertakings. The scientists also benefited from adequate training in computer analytical techniques, most notable in the area of model applications, graphics; including map, contour plotting, remote sensing interpretation, GIS; and interpretation of water quality data. The scientist obtained both practical and theoretical knowledge, thus are now able to integrate and apply a number of scientific disciplines to problems of relating to the water quality monitoring of the lake and its ecosystem, in addition to environmental management and conservation of the catchment. By participating in high level courses in addition to computer training and fieldwork, the scientists have now acquired an in-depth understanding of the fundamental principles of limnology and water quality monitoring. The scientists of this programme are now well-grounded field specialists, who apart from their high specialization in water related issues appreciate the exigencies of other related disciplines. Their specializations within an interdisciplinary/transdisciplinary framework have resulted in versatile international scholars armed with knowledge, awareness and skills to assess and solve pertinent environmental issues and problems afflicting the lake. Apart from training, some infrastructure for water quality monitoring has been established in the lake basin. In Kisumu, laboratories based at the Ministry of Water and Irrigation at Nyalenda was rehabilited and equipped with more sophisticated equipment. However, there is need to build and equip more laboratories in the lake region to lessen transportation and enable quicker analysis of samples. There is now a basin-wide network for data collection in the inshore and offshore areas in addition to establishment of a meteorological network. Monitoring programs have involved placement and utilization of the harmonized monitoring network. Quality control and quality assurance mechanisms is now practiced and coordinated by the component. LVEMP has put emphasis on establishment of internal and regional quality assurance mechanisms, enhancement of laboratory performances and efficiency, and data generation and management. Although research vessels were obtained from the Kenya Marine and Fisheries Research Institute, this arrangement was not efficient since the vessels were obtained only at the discretion and convenience of the latter; it would probably be better if the component could acquire its own vessel to guarantee effective implementation of logistics.

Description: Published

Description: Implementation of the subcomponent on Management of Industrial and Municipal Effluents (MIME) under the LVEMP project was aimed at addressing various deficiencies, which contribute to the overall problem of deterioration of the Lake water quality. The main tasks were to identify and catalogue industries and municipalities that produce organic and inorganic pollutants including nutrients; to collect pertinent information relating to each industry such as industry location, process water requirements and inputs, outputs, by-products (effluents and solid wastes), and their environmental impacts and to sensitize stakeholders to take a lead role in promoting cleaner technology.

Description: Published