ENHG Lecture: Mangrove Ecosystem Loss on Oman's East Coast: Climate Change in the Mid-Holocene by Valeska Decker

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About the talk: Sedimentological, geochemical and palaeontological investigations of the coastline of northeastern Oman provide an in-depth insight into Holocene sea level and climate conditions. The spatial distribution and species assemblage of mangrove ecosystems are analysed. These are sensitive to changes in sea level and precipitation and thus reflect the ecological conditions. The close proximity to archaeological sites allows us to conclude an human interaction with the mangrove ecosystems. Our interdisciplinary investigations reveal that the mangrove ecosystem collapsed along the eastcoast of Oman ca. 6000 cal yr BP at a decadal scale. There is no sedimentological evidence for a Mid-Holocene sea level highstand. The reason for the ecosystem collapse was neither sea level variation, nor anthropogenic interferences, but lowering of precipitation values related to a southward shift of the Intertropical Convergence Zone. This results in a decrease of freshwater input and an increase in soil salinity. Aridification caused increased deflation and silting up of the lagoons.

About the speaker: Valeska Decker studied Geosciences at the Institute of Geosciences at Bonn University. She focused on paleoenvironmental research and did her bachelor’s thesis on micropaleontological investigations on African foraminifera and her master’s thesis on pollen analysis of a lake sediment core from Germany. Both theses cover reconstruction of ecological settings and their variability in time. Ms. Decker graduated as M.Sc. Geosciences in 2017. She started her PhD under supervision of PD Dr. Gösta Hoffmann at Bonn University and now focusses on mangrove ecosystems as an indicator for climate and sea level changes within the northern Indian Ocean.