Why we need a Geo-Observatory of Africa’s Oldest Lake / / by Melanie Leng

This summer, Melanie Leng (BGS's Chief Scientist for Environmental Change Adaptation) attended a workshop in Dar es Saleem, Tanzania, with around 70 other scientists from 10 countries, with the aim to form a plan to create a palaeo Geo-Observatory in this region. The Geo-Observatory, in the form of a long sediment core, will contain information on past conditions in Lake Tanganyika and tropical East Africa. Here Melanie tells us about why we need to do research in this region and what happens next…

The Lake Tanganyika team
LakeTanganyika is one of the oldest, largest and deepest freshwater lakes on Earth and has been collecting information in the sediments deposited on the lake bed for an estimated 10 million years. Creating a Geo-Observatory from Lake Tanganyika in the form of a column of sediments from the bottom of the lake going back through time, provides an outstanding opportunity to study these sediments and transform our understanding of processes controlling the local environment.  Such processes could include changes in the plants and animals in and around the lake; the recent dramatic decline in fish stocks (which has huge implications for the people that live on the lakeshores); and perhaps more importantly if these changes are linked to current and past global climate change or volcanism. These studies could also help determine if recent changes are as a result of human activity, through increasing agriculture, industrialisation and human population growth.

Very deep in Lake Tanganyika there are sediments going back many million years (estimated from seismic reflection profiles) so we can also  investigate tropical climate in the Miocene period to a time when global climate was warmer than the preceding Oligocene and the following Pliocene periods. Two major ecosystems first appeared in the Miocene: kelp forests in the oceans and major grasslands on the continents. The expansion of grasslands is correlated to a drying of the continents as global climate warmed. It is important to understand how our ecosystems respond to climate changes especially warmer worlds.

Sunset at Lake Tanganyika
Drilling into the Lake Tanganyika lake bed and subsequently investigating the ‘Geo-Observatory’ will produce continuous information which will be used as a type section for the tropics. The Geo- Observatory requires pooling international funds and expertise and hence we have linked up with the International Continental scientific Drilling Programme (ICDP) – an international organisation that facilitates large international continental drilling projects by pooling membership fees to part fund large scientific drilling projects but also facilitates the operational structure and organisation of the drilling. ICDP funded the workshop in Dar es Salaam which enabled us to develop scientific and logistic plans for drilling the Geo-Observatory. 

More than 70 researchers from 10 countries attended the workshop including colleagues from Tanzania, Burundi and Congo which also allows us to build capacity in these countries. From the UK the following attended and represented a range of international expertise:From the UK the following attended and represented a range of international expertise: myself, Philip Barker and Chris Wollf (Lancaster University), Ellinor Michel and Jonathan Todd (Natural History Museum), Helen Roberts (Aberystwyth University), Charlotte Spencer-Jones (Durham University) and Richard Staff (SUERC).

The workshop participation group comprising more than 70 scientists from more than 10 countries

Now all the delegates all back home we will all be writing applications to our national funders to acquire co-funding for the drilling, science, and training and outreach activities for the people that live around the lake. It’s a hugely ambitious project and may take several years to come to fruition, but we are all working hard to make sure the Geo-Observatory is delivered to answer some of the most pressing questions in the changing East African climate.

For more information follow Melanie and IDCP on Twitter, and ICDP on Facebook.