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Multiporate Poaceae pollen grains observed in the recent fossil record from the Greater Serengeti Ecosystem and Lake Victoria region
(Elsevier, 2025-02-01) Mustaphi, Colin; Camara-Brugger, Sandra; Ekblom, Anneli; Munishi, Linus; Kariuki, Rebecca; Shoemaker, Anna; Lane, Paul; Marchant, Rob
The analysis of fossil pollen from sediments is used to understand past vegetation and land cover variability. The observations of multiporate Poaceae pollen from sediments have received little attention in the literature and causes and rates of occurrence have few estimates, and the rates observed in the sediments are much lower than estimates observed from modern plants in Asia. Pollen analysis of the uppermost sediments from Speke Gulf, Lake Victoria, eastern Africa, showed relative abundances of Poaceae between 65 and 75% during the past centuries. A total of 19 of the ∼ 11,000 Poaceae pollen grains observed had conspicuous morphological variations and were documented. More consistent presence of abnormal grains occurred since the mid twentieth century, at the same time of increased anthropogenic environmental stressors. Multiporate pollen grains of Poaceae have been previously observed in Asia, South America, and northern Africa, predominantly in the Panicoideae subfamily. Morphological variations may present an added challenge for automated pollen identification techniques and descriptions of fossil pollen.
Multiple paleofire proxy metrics from tropical lake sediment and soil in the Greater Serengeti Ecosystem
(Sage, 2025-06) Mustaphi, Colin; Camara-Brugger, Sandra; Chellman, Nathan; Muñoz, Samuel; Kariuki, Rebecca; Damber, Maja; Shoemaker, Anna; Ekblom, Anneli; Munishi, Linus; Lane, Paul; Marchant, Rob; Heiri, Oliver
Black carbon is a paleofire proxy that has been measured from glacial ice, snow, soils and lake sediments, though relatively few comparisons have been made with other fire indicators in sedimentary geoarchives. Microscopic charcoal, quantified from palynological microscope slides and macroscopic charcoal, quantified from wet-sieved deposits, are the most commonly applied methods for paleofire interpretation of Quaternary sediments. This research explores the down-profile patterns across three paleofire proxies (refractory black carbon, microscopic and macroscopic charcoal) and potential paleofire interpretations from a sediment core dating to the last centuries from Speke Gulf, Lake Victoria, and a young soil profile from a kopje located in the surrounding watershed in Serengeti National Park, Tanzania. The results of three paleofire metrics show similar trends within each site, with a positive trend across all metrics and increasing variability with increased measurement values (heteroscedastic). Notably, refractory black carbon (rBC) concentrations are two orders of magnitude higher in lake sediment samples compared to soil samples. rBC is positively correlated with both microscopic and macroscopic charcoal values and the overall profile patterns down the sediment core are similar, with the exception of the rBC increases from 2.5 to 0 cm depth that may result from increased fossil fuel combustion. The Speke Gulf rBC measurements are in an intermediate range between those published from glacial ice and other lake sediments. New rBC records from different ecosystems and temporal scales will provide paleofire insights and potential to interpret source areas and depositional patterns. The exploration of soil archives offers the potential to exploit semi-arid ecosystems and archaeological sites that have no nearby traditional paleoenvironmental study site targets.
Social determinants for household clean water accessibility in northern Tanzania: A case of Kikwe peri-urban ward in Arusha
(African Quarterly Social Science Review, 2025) Ngayaga, Mwahija; Nade, Paschal; Mpumi, Nelson; Ripanda, Asha; Rwiza, Mwemezi
Clean water accessibility is vital to human health and well-being, a fundamental human right. Over 1.7 billion people do not have consistent access to safe drinking water, negatively affecting their health and socioeconomic status. Despite global recognition of clean water as a fundamental human right, many households in peri-urban areas of developing countries, including northern Tanzania, continue to face significant challenges in accessing reliable water sources. In the Kikwe peri-urban ward, disparities in access to clean water are influenced by various social determinants such as education level, gender roles, marital status, and proximity to water sources. These social factors contribute to unequal water distribution and increased vulnerability to waterborne diseases and economic burdens, especially among women and marginalized groups. However, limited empirical data exists on how these social determinants specifically affect household water access in Kikwe, hindering the development of targeted, evidence-based interventions. This study, therefore, aimed to investigate the social determinants of household clean water accessibility in Kikwe peri-urban ward of northern Tanzania. The cross-sectional survey combined quantitative and qualitative research methods on 353 respondents sampled from the Kikwe ward. Inference and descriptive statistics were employed to analyze the social determinants and respective associations with clean water accessibility. Results show that 64% of respondents finished elementary school, 53% were male, the majority 25.8% aged between 45 to 54, 73.7% were married, 37.4% rely on water from the rivers, 33.7% use public standpipes as the primary source of water, 62.9% female primarily responsible for fetching water and 84.7% of users do not treat water for their daily use. A weak significant correlation existed between water sources and social variables tested, implying clean water is an essential commodity, which needs to be distributed equally regardless of individual status. The findings highlight that clean water accessibility in peri-urban Kikwe is significantly influenced by social inequalities, particularly gender, and proximity to water sources. While the statistical correlations were weak, the trends point to systemic disparities that require deliberate policy attention. It is concluded that equitable access to clean water cannot be achieved without addressing these underlying social determinants. Therefore, it is recommended that targeted educational programs using mobile platforms be introduced to enhance awareness on water treatment and conservation. Additionally, empowering communities through participatory water governance, investing in affordable and decentralized water treatment solutions, and improving local infrastructure is critical for long-term water security and public health resilience in peri-urban areas like Kikwe.
Performance comparison of temperature-based and mass transfer-based horizontal subsurface flow constructed wetland designs
(IWA Publishing, 2025-06-20) Rugaika, Anita; Bruggen, Bart; Njau, Karoli
Two similar horizontal subsurface flow constructed wetlands (HSSF-CWs) that only differ in the wastewater flow length were compared in terms of their performances. The HSSF-CW with a longer wastewater flow length has two baffles, implying that interstitial velocity was considered when designing the system. In contrast, the unbaffled HSSF-CW considered temperature when designing. A significant difference (P < 0.05) was observed between the two systems in the removal of biological oxygen demand (BOD), chemical oxygen demand (COD), ammonia nitrogen, and fecal coliform (FC). Baffled system effluent contained mean BOD levels (32 ± 13 mgO2/L), COD (47 ± 15 mgO2/L), ammonia nitrogen (28 ± 8 mgN/L), and FC (4.4 ± 0.2 log unit). Unbaffled system effluent contained mean BOD levels (38 ± 16 mg/L), COD (57 ± 20 mg/L), ammonia nitrogen (31 ± 8 mgN/L), and FC (5 ± 0.2 log unit). No significant difference (P > 0.05) between the two systems was observed for nitrate nitrogen and phosphorus reduction. In general, the performance of the baffled system was better than the unbaffled one, although both systems complied with the WHO discharge limit for the COD (60 mgO2/L). This confirms that the interstitial velocity is an important parameter in HSSF-CW designing in tropical countries.
“I Don’t Have Time to Exercise”: Determinants of Physical Activity and Diet Consumption Among Adolescents Living with HIV in Southern Tanzania – A Phenomenological Qualitative Study
(Taylor & Francis, 2025-05-22) Maganga, Justina; Katende, Andrew; Luoga, Ezekiel; Nshatsi, Nancy; Siru, Jamal; Sigalla, George; Mollay, Clara; Weisser, Maja; Mtenga, Sally
Background: Low physical activity and unhealthy diets are among the key modifiable risk factors for non-communicable diseases (NCDs), often initiated in adolescence. Little is known about the underlying factors influencing these two behaviors, particularly in adolescents living with HIV (ALHIV). This study aimed at qualitatively exploring the factors perceived to influence physical activity and diet consumption in this vulnerable population.
Methods: Semi-structured in-depth interviews were conducted with ALHIV aged 15 to 19 years (N=22) and their parents and caregivers (N=10) to explore the lived experiences and perceptions regarding physical activity and diet consumption. The interviews were carried out from May to July 2024 at the Chronic Diseases Clinic in Ifakara (CDCI) in Tanzania. Thematic content analysis was performed aided by NVivo software version 14. Three levels of the socio-ecological model (intrapersonal, interpersonal, and community levels) guided the theoretical categorization of findings.
Results: Factors reported to influence physical activity in ALHIV were intrapersonal factors (time constraints, insufficient knowledge); interpersonal (encouragement from family members and peers); and community level aspects (gender and social norms, negative beliefs, inadequate facilities). On the other hand, intrapersonal factors (lack of autonomy, weight gain concerns, food preferences); interpersonal factors (low family income, large family size); and community level factors (increased availability of fast foods) were reported to influence diet consumption among ALHIV. The adolescents’ parents and caregivers similarly shared some of these views.
Conclusion: The findings suggest that both physical activity and diet consumption in ALHIV are influenced by multiple factors in the socio-ecological system. The community, parents and caregivers need to be engaged to provide support systems to address barriers to physical activity and diet consumption in ALHIV. Physical activity and nutrition education need to be integrated into HIV care programs and guidelines to emphasize these health behaviors in this population.