National Repository of Grey Literature 2 records found  Search took 0.01 seconds. 
Late Silurian and Early Devonian Environmental and Biotic Changes
Manda, Štěpán ; Frýda, Jiří (advisor) ; Vašíček, Zdeněk (referee) ; Štorch, Petr (referee)
The mid-Ludfordian crisis (Kozlowskiii/Lau Event) was studied in detail. The extinction coincided with short-term shallowing, which reflected short glacial periode, as well as with incipient increase of organic carbon δ13 C in sediments. As suggested by many authors, this crisis affected especially graptolites and conodonts, but new data illustrate that all benthic groups were affected by the extinction. In addition, the structure of communities distinctly changed during the event. Recovery of ecosystems was accompanied by large-scale immigration of new fauna, contemporaneously with shallowing. The post-extinction interval took place during high stand and anoxic period. Extinction intervals coincide with sequence boundaries associated with gaps in sedimentation. So far poorly studied cephalopods were chosen as a model group for examination of trends in macroevolution and global change of ecosystems during the Silurian and Devonian. New established cephalopod groups that differ in embryonic strategy and mode of life of early hatched specimens and adults were used in study of biodiversity and selectivity of extinctions. The early ontogenetic strategies and size of eggs (incubation time) of the cephalopods significantly influenced survival and diversity during extinction intervals. It was documented...
Late Silurian and Early Devonian Environmental and Biotic Changes
Manda, Štěpán ; Frýda, Jiří (advisor) ; Vašíček, Zdeněk (referee) ; Štorch, Petr (referee)
The mid-Ludfordian crisis (Kozlowskiii/Lau Event) was studied in detail. The extinction coincided with short-term shallowing, which reflected short glacial periode, as well as with incipient increase of organic carbon δ13 C in sediments. As suggested by many authors, this crisis affected especially graptolites and conodonts, but new data illustrate that all benthic groups were affected by the extinction. In addition, the structure of communities distinctly changed during the event. Recovery of ecosystems was accompanied by large-scale immigration of new fauna, contemporaneously with shallowing. The post-extinction interval took place during high stand and anoxic period. Extinction intervals coincide with sequence boundaries associated with gaps in sedimentation. So far poorly studied cephalopods were chosen as a model group for examination of trends in macroevolution and global change of ecosystems during the Silurian and Devonian. New established cephalopod groups that differ in embryonic strategy and mode of life of early hatched specimens and adults were used in study of biodiversity and selectivity of extinctions. The early ontogenetic strategies and size of eggs (incubation time) of the cephalopods significantly influenced survival and diversity during extinction intervals. It was documented...

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