Anthropogener und natürlicher Einfluss auf die Umweltbedingungen des Küstenökosystems von Süditalien während der letzten 5000 Jahre
Zusammenfassung der Projektergebnisse
To obtain insight in the relationship between human activity and changes in environmental conditions of the South Italian coastal ecosystem we studied the relationship between sub-decadal (threeannual) changes in vegetation and marine environmental conditions during pre-industrial key intervals of major climatic change namely the late “Little Ice Age” (~1700 – 1800 AD), and the „Roman Period“ (200 BC – 600 AD). Furthermore, we investigated what processes control the modern distribution of palynological components of terrestrial origin in the marine environments of the western Adriatic Sea and Gulf of Taranto. The first study focused on the transport ways, distribution, provenance and associations of pollen and spores in the Adriatic Sea and Gulf of Taranto. For this, the pollen/spores content of surface sediments from 7 eastern Italian river mouths and 55 marine sites was investigated. Comparison of the marine palynological association with that of the investigated rivers and the main wind systems in the region allowed the recognition of both fluviatile and wind transport. Four characteristic associations could be determined reflecting a pollen source in the drainage areas of 1) the Po-river and north-Apennine rivers, 2) central Italian Apennine draining rivers, 3) mixed signal and 4) a southern Italian signal. The second study focus on the establishment of a high-quality age model for core DP30PC recovered from the Gulf of Taranto (southern Italy). For this, 550 samples from the upper two sections of the core sections representing roughly the last 2000 years of sedimentation were analyzed on their volcanic glass shards content. Glass charts of selected ash layers were analyzed on their minor and major element composition with a microprobe. In contrast to suggestions in previous studies that the major ash deposits at this site origined from the Summa Vesuvius and Ischia outbreaks at 472 AD and 1302 AD respectively, we discovered that the glass charts in this core originated from outbreaks of volcanos on the Island Lipari that have taken place between 400- 524 AD (starting dates) and 1220-1300 (end date). Unfortunately, microprobe analyses of the last four ash layers that are crucial to verify the current provisional age model could not yet be executed due to the current corona crisis. The third and fourth studies executed within the scope of this project provided dinoflagellate cyst based reconstructions of marine environmental conditions for the late little ice age (1700-1800 AD) and Roman times (200 BC – 600 AD) with a three-annual resolution. Reconstructed temperature and river discharge fluctuations in both investigated time intervals showed cyclic changes that could be addressed to changes in solar insolation and changes in climate related to the north Atlantic oscillation. A strong correlation between local climatic change and the occurrence of the first epidemics and pandemics in Europe could be observed.
