My Research – North Africa and the Oceans

During my PhD at Southampton I am researching how North African climate has varied over the last few hundred thousand years.

With predicted changes in future climate it is important to understand how these may impact upon Africa. For example, it is possible that slower Atlantic Ocean circulation will lead to reduced rainfall in North Africa.  This could cause extended periods of drought, which could, in turn, lead to increased migration out of the region.  On a lighter note, the timing of climatic changes in North Africa is likely to have had an impact on when early humans migrated out of Africa!

When I say North Africa you’re probably imagining an image like the one below, a classic Saharan scene with sand dunes and not a lot of water.

(I took this photo in southern Morocco in 2013)

However, it has not always been so dry.  At times in the past, North Africa has supported much more vegetation with grasses, shrubs, rivers and even lakes! It may have looked something more like this…

Image from Wezel, A., Schlecht, E. (2004): Inter-annual variation of species composition in plant communities of semi-arid Niger. Journal of Arid Environments 56 (2): 265-282.

 

North African climate is sensitive to changing Atlantic Ocean circulation which, in turn, is affected by the rate and nature of the saline water flowing out of the Mediterranean Sea.

Source: Penn State. http://news.psu.edu/story/349679/2015/03/24/research/scientists-weakening-gulf-stream-could-impact-marine-life-weather

By studying deep sediments off the coast of North-West Africa and the South-West Iberian margin I can tie together changes in Mediterranean outflow and Atlantic Ocean circulation with changes in African climate.

I will be using a combination of magnetic and geochemical methods. By applying different magnetic fields to samples of sediment and measuring the resultant changes in its magnetic properties I can identify particular minerals as well as changes in grain size, both of which can help to determine past climate changes.  Measuring the proportions of the different chemical elements in the sediment will also help with this.

The project should help us to determine how, when and why North African climate has switched between these wet and dry intervals in the past.

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