Research Repository :: Browsing by Author "Lugomela, Charles"

Browsing by Author "Lugomela, Charles"

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Academic Journals Food Preference of the Sea Urchin Tripneustes Gratilla (Linnaeus, 1758) In Tropical Seagrass Habitats at Dar Es Salaam, Tanzania
(2010-12) Lyimo, Thomas J.; Mamboya, Florence; Hamisi, Mariam; Lugomela, Charles
The sea urchin Tripneustes gratilla is the most well-known seagrass grazer in the Western Indian Ocean and a few cases of overgrazing have been reported. However, few studies on their feeding preference have been performed in this region. In this study, the food items in the gut contents of T. gratilla collected from seagrass beds and in a bare sediment in intertidal areas of Dar es Salaam, Tanzania, were analysed and compared to their availability in the surrounding environment. A total of 59 micro and macro-algae species were identified from the environment and the guts of T. gratilla, of which 48 were found in both gut contents and the environment. Gut contents of T. gratilla collected from mono specific seagrass habitats were dominated by the species in which they were found. In a mixture of four different seagrass species, Syringodium isoetifolium was preferred (with electivity indices (E*) of +0.36) while Cymodocea rotundata, Halodule uninervis and Thalassia hemprichii were slightly avoided (E* = -0.24, -0.22 and -0.22, respectively). We concluded that T. gratilla generally feeds on available seagrass species. However, in the presence of different types of seagrasses it showed preference to S. isoetifolium possibly due to presence of high epiphyte load which may increase its palatability.
Assessment of Faecal Bacteria Contamination in Selected Coastal Waters of Tanzania
(Macrothink Institute, 2013) Lazaro, Samson; Mwakalobo, Samson; Thomas, Jacob; Lyimo, Thomas J.; Lugomela, Charles
Coastal communities of Tanzania use natural water systems such as rivers, estuaries and 64 marine for various activities like drinking, fishing, washing and bathing. However, there is scanty information on the safety for these water bodies for the various uses. In this study faecal indicator bacteria were assessed in three sites along the coast of Tanzania (i.e. Pangani Estuary in Tanga Region, Ruvu Estuary in Pwani Region and Mzinga Creek in Dar Es Salaam Region). At each site, three sampling stations covering fresh, brackish and marine waters were selected for monthly sampling between July 2009 and June 2010. Faecal bacterial indicators were generally higher in Mzinga Creek compared to the rest of the study sites with significant differences between Mzinga Creek and Pangani Estuary for total coliforms (TC) and faecal coliforms (FC) (P < 0.05). All faecal indicator bacteria were significantly higher in fresh waters compared to brackish and marine waters (P = 0.0001), for TC and FC and P = 0.001 for Enterococcus (ENT). The faecal indicator bacteria correlated positive to each other and negatively to some environmental parameters namely pH and Salinity. Results suggest allochthonous sources of contamination and the influence of environmental factors. Generally the faecal bacterial indicators in the studied waters along the coast of Tanzania were within the acceptable standards according to WHO and USEPA indicating low risks situation for recreational purposes. However, these levels of faecal bacteria does not warrant the use in the studied estuaries for shellfish harvesting and the fresh water is not suitable for direct drinking. Further studies and monitoring programs are recommended to substantiate the current results.
Assessment of Faecal Bacteria Contamination in Selected Coastal Waters of Tanzania
(2013-03) Mwakalobo, Samson L.; Namkinga, Lucy; Lyimo, Thomas J.; Lugomela, Charles
Coastal communities of Tanzania use natural water systems such as rivers, estuaries and marine for various activities like drinking, fishing, washing and bathing. However, there is scanty information on the safety for these water bodies for the various uses. In this study faecal indicator bacteria were assessed in three sites along the coast of Tanzania (i.e. Pangani Estuary in Tanga Region, Ruvu Estuary in Pwani Region and Mzinga Creek in Dar Es Salaam Region). At each site, three sampling stations covering fresh, brackish and marine waters were selected for monthly sampling between July 2009 and June 2010. Faecal bacterial indicators were generally higher in Mzinga Creek compared to the rest of the study sites with significant differences between Mzinga Creek and Pangani Estuary for total coliforms (TC) and faecal coliforms (FC) (P < 0.05). All faecal indicator bacteria were significantly higher in fresh waters compared to brackish and marine waters (P = 0.0001), for TC and FC and P = 0.001 for Enterococcus (ENT). The faecal indicator bacteria correlated positive to each other and negatively to some environmental parameters namely pH and Salinity. Results suggest allochthonous sources of contamination and the influence of environmental factors. Generally the faecal bacterial indicators in the studied waters along the coast of Tanzania were within the acceptable standards according to WHO and USEPA indicating low risks situation for recreational purposes. However, these levels of faecal bacteria does not warrant the use in the studied estuaries for shellfish harvesting and the fresh water is not suitable for direct drinking. Further studies and monitoring programs are recommended to substantiate the current results.
Autecology of the Toxic Dinoflagellate Gambierdiscus toxicus Adachi et Fukyo (Dinophyceae) in Central Coastal Areas of Tanzania
(2006) Lugomela, Charles
Biological N2-fixation on Mangrove Pneumatophores: Preliminary Observations and Perspectives
(2002) Lugomela, Charles; Bergman, Birgitta
Co-variation of Cholera with Climatic and Environmental Parameters in Coastal Regions of Tanzania
(2014-01) Lugomela, Charles; Lyimo, Thomas J.; Namkinga, Lucy A; Moyo, Sabrina; Goerricke, Ralf; Sjöling, Sara
The bacterium causing cholera, Vibrio cholerae, is essentially a marine organism and its ecological dynamics have been linked to oceanographic conditions and climate. We used autoregressive models with external inputs to identify potential relationships between the number of cholera cases in the coastal regions of mainland Tanzania with climatic and environmental indices (maximum air temperature, sea surface temperature, wind speed and chlorophyll a). Results revealed that, between 2004 and 2010, coastal regions of mainland Tanzania inhabited by approximately 21% of the total population accounted for approximately 50% of the cholera cases and 40% of the total mortality. Significant co-variations were found between seasonally adjusted cholera cases and coastal ocean chlorophyll a and, to some degree, sea surface temperature, the outbreaks lagging behind by one to four months. Cholera cases in Dar es Salaam were also weakly related to the Indian Ocean Dipole Mode Index, lagging by five months, suggesting that it may be possible to predict cholera outbreaks for Dar es Salaam this period ahead. The results also suggest that the severity of cholera in coastal regions can be predicted by ocean conditions and that longer-term environmental and climate parameters may be used to predict cholera outbreaks along the coastal regions.
Cyanobacteria blooms—A possible cause of mass mortality of Lesser Flamingos in Lake Manyara and Lake Big Momela, Tanzania
(Elsevier, 2006) Lugomela, Charles; Pratap, Harish B.; Mgaya, Yunus D.
Limnological studies were conducted in three alkaline lakes (Lake Big Momela, Manyara and Embagai) with the aim of investigating the cause of mass mortality of the Lesser Flamingos in Lake Manyara and Lake Big Momela during July–August 2004. High concentrations, up to 150 million filaments per liter of the potentially toxic planktonic cyanobacterium Arthrospira fusiformis were found in surface scum of Lake Big Momela where Lesser Flamingos were dying at a rate of between 15 and 50 individuals per day during the study period. Gut content analyses indicated that A. fusiformis was the main food item in moribund flamingos. Mouse bioassay suggested that the crude microalgal extract dominated by A. fusiformis was toxic with all mice close to death becoming lethargic, with loss of balance, uncoordinated movements, intermittent tremors, dyspnoea with gasping followed by respiratory arrest. This observation gives circumstantial evidence that A. fusiformis at such high concentrations was toxic to the Lesser Flamingo in Lake Big Momela. # 2005 Elsevier B.V. All rights reserved.
Cyanobacterial Diversity and Nitrogen Fixation in Coastal Areas around Zanzibar, Tanzania
(Schweizerbart, 2001) Lugomela, Charles; Bergman, Birgitta; Waterbury, J.
Cyanobacterial diversity and nitrogen fixation were examined in coastal areas around Zanzibar, Tanzania. Samplings were performed intermittently from June 1997 to October, 1999 from plankton, intertidal and subtidal microbial mats as well as from epiphytes on seagrasses and seaweeds. A total of 21 cyanobacterial genera comprising 50 species are described, out of which 64% were filamentous non-heterocystous forms, 24% heterocystous forms and 12% unicellular forms. Non-heterocystous Oscillatoria spp. dominated the microbial mats and epiphytic habitats, and the like-wise non-heterocystous Trichodesmium spp. were the most abundant cyanobacteria in net samples. Fourteen of the species identified were analyzed for the ability to fix dinitrogen using the acetylene reduction assay and eleven species showed nitrogenase activity. Six of these species were also subjected to immuno-blotting. The presence of a nitrogenase (Fe-protein) protein with an average molecular weight of 36 kDa was detected. The results suggest higher cyanobacterial diversity in the area investigated than previously reported and indicate that the capacity to fix molecular nitrogen is present in a number of species that are often prominent in these habitats. It is therefore concluded that cyanobacteria may have an important role and may contribute to new N-production in coastal areas of Tanzania.
Diurnal Expression of Hetr and Diazocyte Development in the Filamentous Non-Heterocystous Cyanobacterium Trichodesmium Erythraeum
(2003) El-Shehawy, Rehab; Lugomela, Charles; Ernst, A.; Bergman, Birgitta
The marine non-heterocystous cyanobacterium Trichodesmium fixes atmospheric N2 aerobically in light. In situ immunolocalization/light microscopy of NifH revealed that lighter, non-granulated cell regions observed correspond to the nitrogenase-containing diazocyte clusters in Trichodesmium IMS101. The number of diazocyte clusters per trichome varied from 0 to 4 depending on trichome length. The constant percentage of diazocytes (approx. 15 %) in cultured strains and five natural populations suggests a developmentally regulated differentiation process. Real-time RT-PCR showed that ntcA, encoding the global nitrogen regulator in cyanobacteria, and hetR, the key regulatory gene in heterocyst differentiation, are both constitutively expressed during a 12 h/12 h light/dark cycle. hetR in addition showed a distinct peak in the dark (close to midnight) while nifH expression commenced 6–8 h later. The expression of all three genes was negatively affected by addition of ammonia. Some early heterocyst differentiation genes were also identified in the genome of Trichodesmium. The data suggest that hetR and ntcA may be required for development and function of diazocytes in Trichodesmium.
Existence of Potentially Harmful Microalgae in Coastal Waters around Zanzibar: A Need for a Monitoring Programme?
(1999) Kyewalyanga, M.; Lugomela, Charles
A nine-month survey of potentially harmful microalgae was carried out in the coastal waters around Unguja Island, Zanzibar, from September 1998 to June 1999. Using a light microscope, more than 20 species were identified. These were distributed among three major microalgal groups: the cyanobacteria, mostly dominated by Trichodesmium spp; the dinoflagellates, dominated by Prorocentrum spp. and Gambierdiscus toxicus; and the diatoms, mostly Pseudo-nitzschia spp. This and other preliminary studies indicate the presence of harmful microalgae in Zanzibar waters. Further studies to assess both spatial and temporal distribution, as well as potential ecologic and economic effects, are recommended.
Food Preference of the Sea Urchin Tripneustes Gratilla (Linnaeus, 1758) In Tropical Seagrass Habitats at Dar Es Salaam, Tanzania
(2011) Lyimo, Thomas J.; Mamboya, Florence; Hamisi, Mariam; Lugomela, Charles
The sea urchin Tripneustes gratilla is the most well-known seagrass grazer in the Western Indian Ocean and a few cases of overgrazing have been reported. However, few studies on their feeding preference have been performed in this region. In this study, the food items in the gut contents of T. gratilla collected from seagrass beds and in a bare sediment in intertidal areas of Dar es Salaam, Tanzania, were analysed and compared to their availability in the surrounding environment. A total of 59 micro and macro-algae species were identified from the environment and the guts of T. gratilla, of which 48 were found in both gut contents and the environment. Gut contents of T. gratilla collected from mono specific seagrass habitats were dominated by the species in which they were found. In a mixture of four different seagrass species, Syringodium isoetifolium was preferred (with electivity indices (E*) of +0.36) while Cymodocea rotundata, Halodule uninervis and Thalassia hemprichii were slightly avoided (E* = - 0.24, -0.22 and -0.22, respectively). We concluded that T. gratilla generally feeds on available seagrass species. However, in the presence of different types of seagrasses it showed preference to S. isoetifolium possibly due to presence of high epiphyte load which may increase its palatability.
Genetic Relationship Between Clinical and Environmental Vibrio Cholera Isolates in Tanzania: A Comparison Using Repetitive Extragenic Palindromic (REP) and Enterobacterial Repetitive Intergenic Consensus (ERIC) Fingerprinting Approach
(Academic Journals, 2015-02) Dalusi, Lucy; Saarenheimo, Jatta; Lyimo, Thomas J.; Lugomela, Charles
The bacterium causing cholera, Vibrio cholerae, is a marine organism and coastal waters are important reservoirs of the organism. There are more than 200 serogroups of V. cholerae, of which serogroups O1 and O139 are known to be the causative agent of the cholera. The main virulent factor in V. cholerae is cholera toxin gene (ctx) that is found from the epidemic O1 and O139 strains, but may also be found in some strains other than O1 and O139 (non-O1 and non-O139). In this study, 48 V. cholerae strains isolated from three estuaries of Tanzania and 20 stool isolates were characterized in terms of their serogroups and possession of ctx gene and then compared using two PCR based fingerprinting methods: Enterobacterial repetitive intergenic consensus (ERIC) sequences and repetitive extragenic palindromic (REP) sequences. All the stool isolates and twelve of the environmental isolates belonged to serogroup O1 while the remaining 36 environmental isolates were defined as non-O1/O139. The entire stool isolates and 21 of the environmental isolates had the cholera toxin gene (ctxA). Both ERIC and REP methods gave almost unique fingerprints for each strain and confirmed high genetic heterogeneity among the different cholera strains. Higher similarity was observed in REP-PCR (70- 100%) than in ERIC-PCR (62-100%), indicating different discriminative power of these methods. Environmental isolates clustered together with clinical isolates at ≥90% similarity level suggesting their great potential of producing pathogenic strains that may be the causative agents for the frequent observed cholera outbreaks particularly along the coast.
Genetic Relationship between Clinical and Environmental Vibrio Cholera Isolates in Tanzania: A Comparison Using Repetitive Extragenic Palindromic (REP) and Enterobacterial Repetitive Intergenic Consensus (ERIC) Fingerprinting Approach
(2015) Dalusi, Lucy; Saarenheimo, Jatta; Lyimo, Thomas J.; Lugomela, Charles
The bacterium causing cholera, Vibrio cholerae, is a marine organism and coastal waters are important reservoirs of the organism. There are more than 200 serogroups of V. cholerae, of which serogroups O1 and O139 are known to be the causative agent of the cholera. The main virulent factor in V. cholerae is cholera toxin gene (ctx) that is found from the epidemic O1 and O139 strains, but may also be found in some strains other than O1 and O139 (non-O1 and non-O139). In this study, 48 V. cholerae strains isolated from three estuaries of Tanzania and 20 stool isolates were characterized in terms of their serogroups and possession of ctx gene and then compared using two PCR based fingerprinting methods: Enterobacterial repetitive intergenic consensus (ERIC) sequences and repetitive extragenic palindromic (REP) sequences. All the stool isolates and twelve of the environmental isolates belonged to serogroup O1 while the remaining 36 environmental isolates were defined as non-O1/O139. The entire stool isolates and 21 of the environmental isolates had the cholera toxin gene (ctxA). Both ERIC and REP methods gave almost unique fingerprints for each strain and confirmed high genetic heterogeneity among the different cholera strains. Higher similarity was observed in REP-PCR (70-100%) than in ERIC-PCR (62-100%), indicating different discriminative power of these methods. Environmental isolates clustered together with clinical isolates at ≥90% similarity level suggesting their great potential of producing pathogenic strains that may be the causative agents for the frequent observed cholera outbreaks particularly along the coast
Influence of Land Use Patterns on some Limnological Characteristics in the South-Eastern Part of Lake Victoria, Tanzania
(Taylor & Francis Group, 2011-09-08) Shayoa, Salome D.; Lugomela, Charles; Machiwa, John F.
To investigate the influence of human activities on limnological characteristics of Lake Victoria, we analyzed inorganic nutrient concentrations, phytoplankton diversity and biomass at three locations with different land use patterns: Mwanza (urban/industrial), Magu (agricultural) and Kayenze (sparsely populated). Mwanza had significantly higher ammonia concentration compared to Kayenze and Magu. At the shoreline stations, significantly higher nitrate concentration was observed at Mwanza compared to Kayenze and Magu. Similarly, Mwanza had significantly higher concentrations of soluble reactive phosphorous in the shoreline stations compared to Magu and Kayenze, but not in the open waters stations. Shoreline stations also showed significant differences in phytoplankton diversity among sites. The shoreline station at Mwanza also showed significantly higher levels of Chl. a compared to those at Magu and Kayenze. However, in the open water stations Chl. a concentrations did not differ significantly among sites. The results suggested that urban pollution in Mwanza and agricultural activities in River Simiyu catchment strongly influence the limnology of Lake Victoria and that the nearshore waters, which are the receiving points, were highly impacted compared to the waters outside bays. Thus, proper urban waste management and sustainable land management practices are critical for reducing point and non-point sources of pollution into Lake Victoria.
Nitrogenase Activity in Intertidal Sediment Along the Tanzanian Coast, Western Indian Ocean
(2006) Lyimo, Thomas J.; Lugomela, Charles
Nitrogenase activity was determined using the acetylene reduction assay in the littoral areas near Tanga, Dar es Salaam and Mafia with the aim of investigating its spatial and temporal distribution along the Tanzanian coastal line. Ethylene (C2H4) production rates ranged from 0.07 - 13.5 nmol C2H4 cm-2h-1 in Tanga area, 0.30 - 5.43 nmol C2H4 cm-2h-1 in Dar es Salaam and from 0.10 - 6.25 nmol C2H4 cm-2h-1 in Mafia. Significantly higher rates of nitrogenase activity were measured during night-incubated samples compared to daytime incubated samples suggesting that the sediments were mostly composed of non-heterocystous diazotrophic organisms. However, there were no significant differences in rates of nitrogenase activity between the rainy and dry season and between the sandy and muddy beaches. Also, there were no significant differences in nitrogenase activity between the upper, mid and lower littoral zones, and between the three sampling locations, i.e. Tanga, Dar es Salaam and Mafia. A nitrogen fixation rate of 38 mmol N m-2y-1 was estimated. We conclude that diazotrophs contribute a substantial amount of nitrogen input to the Tanzania coastal ecosystems.
Noctiluca Scintillans (Dinophyceae) in Central Coastal Waters of Tanzania: A New Phytoplankton Record for the Area
(2008) Lugomela, Charles
A one-year study (July 2003 – June 2004) to explore the spatial and temporal variability of potentially harmful dinoflagellates was carried out in the central coastal waters of Tanzania. During the course of the study a green dinoflagellate,Noctiluca scintillans, which has cosmopolitan distribution, was encountered for the first time in the coastal waters of Tanzania. It demonstrated a clear temporal distribution with high biomass (up to 30 cells/l) during the northern monsoon period and showed significant negative correlation with temperature and salinity. Noctiluca scintillans was possibly introduced by ballast waters or currents and became established for at least one season, but later disappeared due to the physical-chemical environment and/or competition or predation from other organisms in the water column. The need for a monitoring programme for potentially harmful micro-algae, and introduced alien species in Tanzanian coastal waters, is justified.
Photosynthesis Rates in Cyanobacteria-Dominated Sub-Tidal Biofilms near Zanzibar, Tanzania
(Elsevier, 2005) Lugomela, Charles; Söderbäck, Erik; Björk, Mats
The surface cover (during 1998) and photosynthesis rates (measured intermittently between 1998 and 2000) of submergedcyanobacteria-dominated bioﬁlms near a patchy reef in Zanzibar were determined using a line intercept transect method and pulse-amplitude modulated ﬂuorometer (PAM), respectively. The bioﬁlm surface cover ranged between 5 and 56% with an annual averagevalue of 25%. Photosynthetic activity on deep-dwelling bioﬁlms was low light adapted compared to shallow-dwelling bioﬁlms.Bioﬁlms also regulated their photosynthetic activity depending on the light regime over the day, manifesting high light utilizationcoeﬃcient (a), light saturation index (Ek) and maximum electron transport rate (ETRmax) values at around noon compared tomorning and evening measurements. We calculated carbon ﬁxation rates of 0.05, 0.3 and 0.5 kg C m2y1for thin (w0.5 mm),medium (w1 mm) and thick (w2 mm) bioﬁlms, respectively, and estimated an overall primary production rate of 0.14 kg C m2y1at depths of about 5 m. This study shows that bioﬁlms in the area actively ﬁx carbon and may contribute substantially to theprimary productivity of coastal ecosystems. More experiments are required to precisely determine the absorption factor for robustdetermination of the ETR and to explain the signiﬁcance of the bioﬁlms on the overall productivity of coastal ecosystems.
Plankton Composition and Cycling of Carbon during the Rainy Season in a Tropical Coastal Ecosystem, Zanzibar, Tanzania
(Oxford University Press, 2001-10) Lugomela, Charles; Wallberg, Petra; Nielsen, Torkel G.
Biomass, species composition and production of the planktonic community were investigated during the rainy season in May and June 1999 outside Zanzibar Island, Tanzania. In general, the plankton biomass of different organisms was uniform between depths as well as over time. The integrated water column primary production ranged from 204 to 4142 mg C m–2 day–1. Bacterial production varied between 10 and 72 mg C m–2 day–1, comprising ~5% of the total bacterial standing stock. The data obtained from these experiments are summarized in a carbon budget. At the most 77% of the total primary production channelled through the heterotrophic flagellates, ciliates and heterotrophic dinoflagellates to higher trophic levels. Of the estimated carbon demand for mesozooplankton, 28% could potentially be met by ciliates and heterotrophic dinoflagellates.
Potentially Harmful Microalgae of the Western Indian Ocean. A guide based on a preliminary survey.-UNESCO
(UNESCO, 2001-01) Hansen, Gert; Turquet, Jean; Quod, Jean P.; Ten-Hage, Loïc; Lugomela, Charles; Hurbungs, Mira; Wawiye, P.; Ogongo, Bernard O.; Tunje, S.; Rakotoarinjanahary, H.
Reevaluation of the Nitrogen Fixation Behavior in the Marine Non-Heterocystous Cyanobacterium Lyngbya Majuscula.
(Wiley, 2003) Lundgren, Pernilla; Ininbergs, Karolina; Lugomela, Charles; Söderbäck, Erik; Bergman, Birgitta
Lyngbya majuscula Harvey ex Gomont is a common marine cyanobacterium in tropical and subtropical near-shore waters. A few reports have indicated that L. majuscula fixes nitrogen only in the light. Because this feature is uncommon among non-heterocystous cyanobacteria, we attempted a reevaluation. Nitrogenase activity, regulation, and localization were examined over diel cycles on natural populations of L. majuscula growing in subtidal zones off Zanzibar in the western Indian Ocean. The data show that L. majuscula fixed nitrogen and synthesized nitrogenase in all cells during the dark phase of a diel cycle. During the light phase, nitrogenase was degraded to undetectable levels.

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