Sediments at the bottom of the ocean can provide valuable insights into the past, revealing not only environmental conditions from the sea but also those brought in from terrestrial runoff. These sediments also preserve the flora and fauna of the time. Scientists obtain this knowledge by conducting exploration cruises to collect core samples from the seabed, which are then brought to laboratories for analysis.
In a recent expedition reported in The Holocene, researchers recovered cores from the Gulf of Saint Eufemia on the west coast of Calabria, Italy. Understanding the size of the basin from which the cores are obtained is crucial as it helps identify the spatial distribution of sediments and inclusions, such as pollen and spores. Larger basins can capture material from land located hundreds of meters away, providing information on regional vegetation patterns. On the other hand, smaller basins are more likely to capture material from the immediate vicinity, offering a more localized picture of plant communities.
By studying pollen grains and spores preserved in these cores (palynology), scientists from the University of Naples Federico II, Italy, and their collaborators were able to trace the colonization of Italy by Greeks and Romans over the past 5,000 years. They extracted pollen from the sediment, with an astonishing 12,000 grains per gram of material, and analyzed it under a microscope, identifying 72 species.
The results revealed three distinct phases of vegetation in the region: dense forest cover between 5055 and 2700 years before present (BP), forest decline and aridity between 2700 and 2000 BP, and deforestation with intensive agriculture from 790 BP to the present day.
These vegetation patterns can be closely linked to the communities living in the area at the time. Pre-Protohistoric populations found a home in the dense forest, but they may have started experiencing the effects of climate change. The researchers noted three lengthy periods of hundreds of years in which the vegetation indicated the proliferation of arid conditions in the area.
2023-07-10 14:00:07
Source from phys.org