9 research outputs found
The Physical and Chemical Characteristics of A Phycocolloid from the Red Alga Sarcodia Montagneana
No full textCurrent trends in marine botanical research in the East African region. Proceedings of the 3-10 December 1995 Symposium on the Biology of Microalgae, Macroalgae and Seagrasses in the Western Indian Ocean : University of Mauritius.
No full textMarine systems are extraordinarily diverse in terms of species numbers, genetic variability and ecosystem types, and the ocean floor community is as diverse as terrestrial system. Of the species known to science, it has been estimated that about 20% are marine. However, all the phyla are represented in the sea. It is unfortunate that, despite this range of life, the issue of marine biodiversity in East Africa has not received as much attention as terrestrial systems have. This may be due partly to lack of adequate knowledge of the diversity of the system, but also to the old belief that the sea is inexhaustible. Scientific information available in the region indicates that undesirable human activities such as pollution of the marine environment, coral mining, overfishing and uncontrolled coastal zone development projects pose major threats to marine life. This paper discusses the importance of marine biodiversity for mankind and hence the need for its sustainable utilization for conservation purposes. It also points out gaps in knowledge of the region that require more research input.Publishe
Challenges for marine botanical research in East Africa: Results of a bibliometric survey
No full textA bibliometric review was made of published and grey literature on marine botanical research in the Western Indian Ocean (1950–2000) to evaluate the current status of marine botanical research in the East African region. All literature references indexed in Aquatic Sciences and Fisheries Abstracts, Life Sciences Collection, and other computerised databases, as well as annual reports, bibliographies, web-sites, review articles, cross-references, papers and reports published in grey literature — obtained from various institutions and libraries operating in this region — were systematically analysed to provide a diagnosis of strengths and weaknesses in the marine botanical research in the region to date. The results of the analysis are discussed in order to identify the main challenges to be faced as a solid basis for future research efforts in marine botany in the East African region
The effect of seasons on yield and quality of carrageenan from Tanzanian red alga Eucheuma denticulatum (Gigartinales, Rhodophyta)
No full textSamples were collected monthly from Oyster Bay, Dar es Salaam. Light, temperature, salinity, pH, seawater nitrogen and phosphorus were determined on each sampling period. Mean carrageenan yield was significanlly higher during the SE monsoon period (t = 6.15, P<0.05). Gef strength was significantly higher during NE monsoon period (t = 2.61, P<0.05) and lower during the start of the rainy season particularly in March
Holocene mangrove dynamics and sea level changes: records from the Tanzanian coast
No full textTanzanian mangrove ecosystems have been, and are presently, influenced by changes in climate and sea level. Fluctuations in these environmental conditions lead to adaptations and changes in ecosystem structure and composition. In this thesis mangrove environments are investigated and used to unravel the Holocene environmental history of the Tanzanian coast. Palaeoecological data from sediments abstracted from three different mangrove locations (the Rufiji Delta, Makoba Bay and Unguja Ukuu) are analysed for fossil pollen and charcoal and combined with stratigraphical investigations and radiocarbon dating allow a detailed environmental reconstruction to be undertaken.
The relationship between pollen in surface samples and the surrounding vegetation is used to interpret fossil pollen records. Changes in the relative proportions of mangrove pollen under different inundation regimes are used to reconstruct mangrove dynamics and provide estimates of past sea level changes and infer specific changes in sea level altitude.
Palaeoecological records reveal that mangroves in the Rufiji Delta occurred at the central sites from at least ~5600 cal yr B.P. until the late Holocene when mangroves covered the landward site and were succeeded by terrestrial vegetation to the present day. The Zanzibar records reveal fluctuating mangrove compositions from ~8000 cal yr B.P. to the present day with noticeable changes in mangrove composition during the mid Holocene. A reconstructed sea level curve from the three sites document an early-mid to mid Holocene sea level rise from ~ 8000 cal yr B.P. to around 4600 cal yr B.P. with potential highstands at 5800 cal yr B.P. and 4700 cal yr B.P. Sea level fluctuations occurred in the last thousand years with a potential highstand at ~ 530 cal yr B.P. before falling to a lower than present level at ~140 cal yr B.P. The earliest intensive human interactions within the mangroves was recorded in Zanzibar after ~530 cal yr B.P; a time of increased settlements and overseas trade along the Swahili coast. The Rufiji Delta records also demonstrate the impacts of damming and the destruction of mangrove areas for rice cultivation during the last millennium.
The palaecological data have helped unravel the environmental history of the Tanzanian coast and have the potential to assist in the development of policies and/or public awareness for the sustainable utilization and management of mangrove ecosystems under predicted future sea level and climate changes
The Level of Enzymes Involved in the Allantoin Metabolism of Bacillus-Fastidiosus Grown under Different Conditions
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Characterization of Aptamer-Protein Complexes by X-ray Crystallography and Alternative Approaches
No full textAptamers are oligonucleotide ligands, either RNA or ssDNA, selected for high-affinity binding to molecular targets, such as small organic molecules, proteins or whole microorganisms. While reports of new aptamers are numerous, characterization of their specific interaction is often restricted to the affinity of binding (KD). Over the years, crystal structures of aptamer-protein complexes have only scarcely become available. Here we describe some relevant technical issues about the process of crystallizing aptamer-protein complexes and highlight some biochemical details on the molecular basis of selected aptamer-protein interactions. In addition, alternative experimental and computational approaches are discussed to study aptamer-protein interactions.
Assessing the impacts of nonindigenous marine macroalgae: an update of current knowledge
No full textNonindigenous marine species continue to be one of the foremost threats to marine biodiversity. As an update to a 2007 review of the impacts of introduced macroalgae, we assessed 142 additional publications to describe species’ impacts as well as to appraise information on the mechanisms of impact. Only 10% of the currently known nonindigenous macroalgal species were subjects of ecological impact studies, with changed community composition as the most commonly reported effect. Economic impacts were rarely published. Recent research has focused on the impacts of introduced macroalgal assemblages: red algal introductions to the Hawaiian Islands and turf algae in the Mediterranean. Several general issues were apparent. First, many publications included nonsignificant results of statistical analyses but did not report associated power. As many of the studies also had low effect and sample size, the potential for type II errors is considerable. Second, there was no widely accepted framework to categorize and compare impacts between studies. Information in this updated review was still too sparse to identify general patterns and mechanisms of impact. This is a critical knowledge gap as rates of introductions and hence impacts of nonindigenous macroalgae are expected to accelerate with climate change and increasing global trade connectivity
