Sediments at the bottom of the ocean offer a window into the past

Scientists are charting the colonization of Italy by Greeks and Romans during the past 5,000 years using seafloor cores.
Loukia Papadopoulos
Representational image of sea sediments.jpg
Representational image of sea sediments.


Scientists have been bringing to the surface sediments from the bottom of the ocean that indicate environmental conditions not just from the sea but washed in from terrestrial runoff. They have been sending them for laboratory analysis to figure out certain regions' past conditions.

This is according to a report by published on Monday.

One area where such exploration is taking place is the Gulf of Saint Eufemia, on the west coast of Calabria, Italy. 

There, researchers from the University of Naples Federico II, Italy, and their collaborators were able to study pollen grains and spores preserved in seafloor cores in order to chart the colonization of Italy by Greeks and Romans during the past 5,000 years.

What the findings show

The findings showed three distinct phases of vegetation in the region: dense forest cover between 5055 and 2700 years before the present (BP), forest decline and aridity between 2700 and 2000 BP, and deforestation with intensive agriculture from 790 BP to the present day.

These patterns can be associated with the Pre-Protohistoric communities living in the area at the time.

The second phase of vegetation can be recognized by agricultural intensification based upon the preservation of cereals and herbs of the Cichorieae tribe corresponding to the rise of Greek (7th to 5th century BC) and Roman (3rd to 2nd century BC) populations.

In the third and final phase, widespread deforestation destabilized soil and increased water runoff. There is an indication of a sudden decline in land management, signifying a ruralization linked to the collapse of the Western Roman Empire in the region.

Researchers can combine palynology with archaeological studies of the Mediterranean basin to understand vegetation changes as a result of human occupation of the area. The results indicate that the climate in Italy over the last 5,000 years (middle and late Holocene) has been punctuated by a series of cooler and drier periods.

Today, the region is populated by turkey oak and beech, according to, with a smaller contribution of firs, while pine and oak are found along the coast, alongside agricultural land. Will palynologists of the future struggle to make sense of today’s environment? Only time will tell.

The study is published in the Sage Journal.

Study abstract:

Pollen analysis of a marine core collected in the Gulf of S. Eufemia (Tyrrhenian Calabria, Italy) allowed reconstructing the regional changes in vegetation and land use over the last 5000 years. Pollen diagram zonation through Constrained Cluster Analysis highlighted three compositional zones whose boundaries mark the major changes that affected the vegetation structure. A dense forest cover with a few signs of human activities characterized the wide pollen source area from 5055 to 2700 BP (Zone 1). In this period, the Pre-Protohistoric communities were mainly concentrated on the Tropea Promontory where they had a significant local impact. Minor forest rarefactions at 5000–4800 BP, ca. 4400–4000 BP, ca. 3450–3150 BP were correlated to phases of climatic shifts toward aridity. From 2700 to 2000 BP (Zone 2a), a longer and more incisive period of forest decline was connected to a time of aridity that favored the intense activities of an increasing anthropogenic pressure. Indeed, important urban centers developed in the area during the Greek and Roman colonization. Diffuse deforestation and cultivation occurred from 790 BP (Zone 3), enhancing soil erosion and fluvial discharge as testified by the sudden increase in sedimentation rates. This disruption of the slope morphodynamics was connected to the collapse of territorial management following the end of the Western Roman Empire. Compositional Data Analysis, applied to a simplified pollen dataset, highlighted both a negative correlation between Abies and Fagus and a close similarity between the AP/NAP curve and the Axis 1 scores of the Relative Variation Biplot.