States of biogenic bedding as records of the interplay of ecologic time and environment (a case study of modern siliciclastic sediments, Mellum Island, southern North Sea)
Gerdes, G.; Klenke, T. (2007). States of biogenic bedding as records of the interplay of ecologic time and environment (a case study of modern siliciclastic sediments, Mellum Island, southern North Sea). Senckenb. Marit. 37(2): 129-144
In: Senckenbergiana Maritima: Wissenschaftliche Mitteilungen der Senckenbergischen naturforschenden Gesellschaft. E. Schweizerbart'sche Verlagsbuchhandlung (Nägele u. Obermiller): Stuttgart. ISSN 0080-889X, more
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| Keywords |
Biofilms
Microbial mats
Sedimentary structures > Biogenic sedimentary structures > Stromatolites
Sedimentation
Microcoleus chtonoplastes (Mertens) Zanardini [WoRMS]; Oscillatoria limosa C.Agardh ex Gomont, 1892 [WoRMS]
ANE, North Sea [Marine Regions]
Marine/Coastal |
| Abstract |
Vertical sequences in modern siliciclastic sediments are used to document the intimate relationship between sedimentation rates and frequency and the development of microbial mats of different successional stages that correspond with hiatal intervals between the sedimentation events. Spatio-temporarily varying types of biogenic bedding developed from the former interaction of surface mats with sedimentation at water/sediment or air/sediment interfaces. Determinants of both surface mats and their bed-per-bed characteristics in the sedimentary record are local dominance changes between the two filamentous cyanobacterial species Oscillatoria limosa and Microcoleus chthonoplastes. Both represent different morphotypes and form mats of different consistency biomass enrichment, structural complexity and thickness. Local dominance changes between both species proceed along an ecologic succession which starts with O. limosa- dominated pioneer mats and progressively continues towards thicker mats in which M. chthonoplastes is abundant. Experiments have shown that both species are able to re-establish surface mats after burial, however, mats dominated by the one or other species require different time spans to return to their reference states before burial. These so-called ecologic time spans largely are controlled by the length of breaks in sedimentation. The spatial distribution of surface mats of different successional stages is converted into the sedimentary record which is characterized by different biolaminite types. The vertically variable buildups underline the importance of different time spans of hiatal intervals in biogenic bedding. |
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