Late Quaternary vegetation, climate and ocean dynamics inferred from marine sediment cores off southeastern South America
by Fang Gu
Date of Examination:2018-02-08
Date of issue:2018-09-04
Advisor:Prof. Dr. Hermann Behling
Referee:Prof. Dr. Hermann Behling
Referee:Prof. Dr. Markus Hauck
Referee:Prof. Dr. Erwin Bergmeier
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Abstract
English
Southeastern South America harbour highly diverse and species-rich ecosystems, such as the Atlantic rainforest, Araucaria forest and grasslands, which occur in a transitional zone from tropical to subtropical. This climatic sensitive region is influenced by different climatic factors, such as the Intertropical Convergence Zone (ITCZ), the South American Monsoon System (SAMS), cold polar fronts and the El Niño–Southern Oscillation (ENSO). The dynamics of Brazil Current (BC) from the north, as well as the Malvinas Current (MC, refers to the term Falkland/Malvinas Current (FMC) in Chapter 4) and Brazil Coastal Current (BCC) from the south, can not only trigger the hydrology changes of western South Atlantic, but also influence the climate in southeastern South America. To reconstruct vegetation, climate and ocean dynamics over long time periods, three marine sediment cores located at a 1400 km long latitudinal transect, from ca. 27 to 38°S, off southeastern South America have been studied by pollen, spore, organic walled-dinoflagellate cysts (dinocyst) and freshwater algae analyses. The study of the three marine sediment cores contributes to a better understanding of past vegetation dynamics, climate change in southeastern South America, surface water conditions and ocean current changes of western South Atlantic over long time periods. It also provides an insight into how the long term global sea level changes can affect the coastal ecosystems in southeastern South America.
Keywords: Southern Brazil; South Atlantic; Pollen; Spores; Dinoflagellate cysts; Environmental changes; Late Quaternary; Climate change; Sea level changes