The changing coastline and its effects on the city of Aden : a study of ostracoda microscopic organisms

الملخص EN

The changing coastline in the area of the city of Aden (Yemen) and its effects on settlements in the region was studied over time for this paper by using the environmental indications of microscopic organisms called Ostracoda, and the evidence of changing sedimentary environments.

The sediment samples for this study were collected vertically from shallow bore-holes excavated along the coastline of Aden to show the differences between the Ostracoda communities and sediments with time through the influence of changing environments.

The study shows a periodic change in sea levels influenced by the influx of sediments from the Tuban Valley (Wadi Tuban), sea currents, and subsidence characteristic of the shoreline.

During rainfall periods particles from the weathering of rocks in adjacent slopes have washed off, and the intermittent valley of Tuban transports these large quantities of sediments to the shoreline.

This has led to tens of centimeters of sediments deposited during one single flood event.

The particles transported along the valley to the coast line are processed and sorted by sea activity.

Also tectonic processes contributed to the formation of the coastline.

The results from this study have agreed with field observations and the previous historical and geographical studies about the city, which concluded that the periodic coastline changes affected the old routes and connections between settlements in the city of Aden during the 19th and 20th centuries.