caa a22 4500 469077530 CHVBK 20180323132939.0 cr unu---uuuuu 170328e19920101xx s 000 0 eng 10.1007/BF00197031 doi (NATIONALLICENCE)springer-10.1007/BF00197031 Spatial and temporal distribution of diatoms in sediments of Lake Malawi, Central Africa, and ecological implications [Elektronische Daten] [R. Owen, R. Crossley] Lake Malawi lies in a major rift valley in Central Africa that is some 700 m deep and 550 km long. A total of 242 cores and 111 grab samples were recovered between 1984 and 1989 and form the data base for a study of diatom distribution in this lake basin. The sediments consist of homogeneous diatomites, pelagic diatomaceous muds, varved diatomite-mud couplets, turbidites, littoral sand sheets and extensive deposits of ferro-manganous nodules. Fossil diatoms show major temporal and regional contrasts between the southern, central and northern areas of the lake. A wide variety of Aulacoseira species occur in the southern lake sediments. To the north, the Nkhotakota region is generally characterised by Stephanodiscus and Aulacoseira, with occasional diatomite laminae composed of Aulacoseira or Nitzschia. The central parts of the lake show the greatest variation, with Stephanodiscus, Nitzschia and Aulacoseira all being prominent. The northern region is dominated by Aulacoseira nyassensis throughout most core sequences. Variability in these assemblages appears to be controlled by Si:P ratios, Si concentrations, turbulence and light penetration. These factors themselves are influenced by differences in the depth and duration of lake mixing due to variations in wind strength, seiches and bottom topography among different regions of the lake and from lakewide circulation patterns. Kluwer Academic Publishers, 1992 Malawi nationallicence sediments nationallicence diatom nationallicence paleolimnology nationallicence paleoecology nationallicence nutrients nationallicence Owen R. Department of Geography, Hong Kong Baptist College, 224 Waterloo Rd., Kowloon, Hong Kong aut Crossley R. The Robertson group Ltd., Llandudno, LL30 1SA, Gwynedd, U.K. aut Journal of Paleolimnology Kluwer Academic Publishers 7/1(1992-01-01), 55-71 0921-2728 7:1<55 1992 7 10933 https://doi.org/10.1007/BF00197031 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00197031 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Owen R. Department of Geography, Hong Kong Baptist College, 224 Waterloo Rd., Kowloon, Hong Kong aut NATIONALLICENCE 700 1- Crossley R. The Robertson group Ltd., Llandudno, LL30 1SA, Gwynedd, U.K aut NATIONALLICENCE 773 0- Journal of Paleolimnology Kluwer Academic Publishers 7/1(1992-01-01), 55-71 0921-2728 7:1<55 1992 7 10933 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer