Journal of Aquatic and Terrestrial Ecosystems

Kabaka's Lake as Microcosm: Climate Change, Urban Pressure and Spring-Fed Water Fragility in Central Uganda

2026-07-24T15:03:23+00:00

Urban water bodies in Sub-Saharan Africa are increasingly positioned at the intersection of climate-driven hydrological stress and rapid demographic transformation. This paper presents a systematic integrative review of the compound pressures facing Kabaka's Lake the largest man-made lake in Uganda situated in Kampala's Lubaga Division in the immediate vicinity of St Lawrence University. Constructed in the 1880s under Kabaka Mwanga II of Buganda and fed principally by underground springs, the lake has historically been buffered from seasonal rainfall variability. However, convergent pressures of regional warming, increasingly erratic precipitation, rapid urban encroachment, and wetland degradation now threaten its ecological integrity. Drawing on peer-reviewed hydrological, climatological, limnological, and governance literature, the review situates Kabaka's Lake as a microcosm of the pressures facing spring-fed urban water bodies across Central Uganda's Lake Victoria catchment. Key findings indicate that the lake's catchment has experienced a 78.5% increase in built-up area and a 92.2% contraction in receiving wetland cover over the past 25 years, while the lake itself is nitrogen-limited and algae-dominated, with Secchi transparency already signalling incipient eutrophic stress and a projected transition to eutrophic status within approximately 25 years absent intervention. The review further maps these pressures onto the United Nations Sustainable Development Goals particularly SDG 6 (Clean Water and Sanitation), SDG 11 (Sustainable Cities and Communities), SDG 13 (Climate Action), and SDG 15 (Life on Land) and identifies persistent governance fragmentation and policy implementation gaps as root causes of management failure. Distinctively, the review leverages the lake's proximity to a Faculty of Education to propose an integrated model of catchment stewardship that couples technical management interventions with place-based environmental education, positioning the lake as a living laboratory for pre-service teacher training in climate-responsive sustainability. The study concludes that the sustainable management of spring-fed urban water bodies in Central Uganda requires simultaneous action across hydrological monitoring, wetland restoration, decentralised wastewater treatment, governance reform and pedagogical innovation.

Breeding Strategies in Silkworm (Bombyx mori) for Environmental Adaptation: A Structured Narrative Review

2026-06-28T10:00:45+00:00

Climate variability increases the exposure of Bombyx mori to heat, humidity extremes, variable mulberry quality and pathogen pressure. The insect's long domestication history improved silk output but also narrowed genetic diversity and increased dependence on managed rearing. This structured narrative review evaluates conventional selection, hybrid breeding, marker-assisted selection, population genomics, transcriptomics and genome editing as strategies for environmental adaptation. English-language literature published from 2000 to 26 June 2026 was identified using combinations of major bibliographic databases and reference-list searches. Studies were assessed according to clarity of genetic material, stress definition, controls, replication, outcome measurement, statistical analysis and source traceability. Owing to substantial heterogeneity in strains, stress treatments and endpoints, the evidence was synthesised thematically rather than meta-analysed. Phenotypic selection and multi-environment hybrid testing remain the most deployment-ready approaches because they measure survival, productivity and silk quality simultaneously. Marker-assisted selection can accelerate introgression when loci are independently validated, whereas pan-genomic and genome-wide association resources expand the search for adaptive alleles and improve parent selection. Transcriptomics and functional studies identify heat-shock, antioxidant, immune and silk-gland pathways, but expression changes require causal validation. CRISPR-based studies have established efficient editing and produced promising antiviral and heat-resistant lines, although regulatory, pleiotropic and seed-system constraints limit immediate field deployment. The review concludes that climate-adaptive breeding should use a staged pipeline combining germplasm conservation, controlled stress screens, measured environmental covariates, cost-effective molecular support and multi-season, multi-location validation. In emerging African sericulture systems, investment in field phenotyping, parental-stock management and delivery of locally tested hybrids is as important as investment in advanced genomics.

Analysis of the Effect of Sector Value added to GDP on Carbon Emissions in Kenya

2026-08-02T09:07:46+00:00

This study examines the asymmetric effect of sectoral value added to GDP on carbon dioxide (CO₂) emissions in Kenya over the period 1990–2021, grounded in the Environmental Kuznets Curve (EKC) theoretical framework. Despite existence of enormous literature examining the linkage between economic growth and carbon emissions, only a few have focused on how growth in different sectors contribute to the establishment of this nexus. Using annual time series data from World Banks’ World Development Indicators database, the study applies the Augmented Dickey-Fuller and Phillips-Perron unit root tests, the Nonlinear Autoregressive Distributed Lag (NARDL) model and Wald tests for asymmetry. The variables considered include carbon emissions as the dependent variable and renewable energy, agriculture value added to GDP, service value added to GDP and industry value added to GDP as the independent variables. The unit root test results under Augmented Dickey Fuller and Philips-Perron indicate that the variables were first difference stationary. The bounds test results confirm the existence of a long-run cointegrating relationship at the 5% significance level, with an error correction term of −0.904. The NARDL results indicate that in the long-run, agriculture value added growth significantly increases CO₂ emissions (+2.734) whereas it’s decline leads to a reduction in emissions (coef. -1.800 p=0.077) in. The service sector growth reduces emissions (−0.213) while it’s decline increases emissions (0.594). Industrial growth on the other hand is associated with lower emissions (−0.727), whereas its decline substantially raises emissions (+5.486). Renewable energy consumption consistently reduces emissions both in the short and long run (-3.755 and -5.036 respectively). Wald tests confirm a strong and significant long-run asymmetry in the service and industrial sectors with agriculture presenting a weak long-run asymmetry (p=0.092). The findings suggest that sectoral composition critically shapes Kenya's emissions trajectory and that policy interventions must distinguish between growth and decline phases. Short-term agricultural policies should prioritize climate-smart farming and sustainable land-use practices, while service sector strategies should emphasize green public transport and digital economy expansion. The anomalous industrial result warrants further investigation with additional controls for fossil fuel energy consumption and structural breaks.

Bioremediation Potential of Actinobacteria in Heavy Metals Contaminated Soils in Kipkenyo Dumpsite, Eldoret, Kenya

2026-05-14T12:55:39+00:00

Contamination of soils by potentially toxic elements poses significant environmental and health hazards globally, especially in mismanaged waste disposal sites. This is due to deposition of solid and liquid substances in the dumpsites and industrial pollutions into the soil which form toxic chemicals as well as evaporation of harmful gases into the atmosphere. This study assessed the bioremediation potential of Actinobacteria in heavy metals contaminated soils in Kipkenyo dumpsite, Eldoret, Kenya. Initial concentrations of Cadmium, Cobalt, Chromium, Copper, Nickel, Iron, Manganese and Zinc were quantified using atomic absorption spectrophotometry. The dumpsite soil samples were characterized to identify the species of bacteria present. The most abundant species were isolated, cultured and used as a positive control in the bioremediation experimental set up. The isolated bacteria were identified using morphological characteristics and biochemical tests using Bergy’s manual of determinative bacteriology. Streptomyces spp. was isolated and cultured from soil samples from the University of Eldoret arboretum. The data was analyzed using R programming language version 4.4.2. The initial concentrations of heavy metal elements in Kipkenyo dumpsite soil samples had significant variations (P˂ 0.05). The final concentrations of elements also showed significant changes in samples treated with either Streptomyces spp. or Bacillus spp compared to that of negative control. Bacillus spp. was the most abundant in the dumpsite soil samples. Zinc had a higher degradation percentage (82.68% in Streptomyces spp. and 80.68% in Bacillus spp.) while chromium had the least percentage degradation (6.49% in Streptomyces spp. and 10.39% in Bacillus spp.). Streptomyces spp. had a higher percentage degradation in most heavy metal elements compared to Bacillus spp. These findings underscore the potential use of native actinobacteria in bioremediating heavy metal-contaminated soils and serve as a basis for creating environmentally friendly dumpsite rehabilitation techniques.

Influence of Agricultural and Agro-Industrial Activities on Nutrient Dynamics and Water Quality in River Keyian, Kenya

2026-07-09T13:17:20+00:00

Freshwater ecosystems adjacent to agro-industrial developments are increasingly threatened by nutrient enrichment, yet the effects on water quality remain uncharacterized. This study evaluated the spatial distribution of nitrate (NO₃⁻), nitrite (NO₂⁻), ammonium (NH₄⁺), soluble reactive phosphorus (SRP), and total phosphorus (TP) in River Keyian, Narok County, Kenya, and assessed nutrient stoichiometry and eutrophication potential downstream of a treated sugar industry effluent discharge point. A total of 112 Water samples were collected bi-monthly from seven river stations and one effluent outlet between January and April 2024 using standard methods. Spatial variation and nutrient relationships were evaluated using one-way analysis of variance (ANOVA), Tukey's Honestly Significant Difference (HSD) test, Pearson correlation analysis, and the dissolved inorganic nitrogen to soluble reactive phosphorus (DIN: SRP) ratio. Nitrate, ammonium, SRP, and TP varied significantly among sampling stations (p < 0.05), whereas nitrite showed no significant spatial variation (p = 0.115). Nitrate increased approximately 1.8-fold, from 9.345 ± 6.073 mg/L upstream to 17.020 ± 3.626 mg/L downstream, while SRP and TP increased approximately 4.1-fold (0.216–0.893 mg/L) and 4.5-fold (0.670–3.009 mg/L), respectively. Total phosphorus exhibited the strongest spatial response (η² = 0.582) and was positively correlated with nitrate and ammonium (p < 0.01), indicating common nutrient sources. The DIN:SRP ratio declined from 37.779 upstream to 8.788 downstream, demonstrating increasing phosphorus availability relative to dissolved inorganic nitrogen and an elevated potential for eutrophication in the lower reaches of the river. The findings indicate that nutrient enrichment in River Keyian is driven by the combined effects of treated sugar industry effluent and diffuse agricultural activities rather than industrial discharge alone. These results provide evidence to support integrated watershed management, improved nutrient removal technologies, and routine water quality monitoring to protect the ecological integrity of River Keyian.