Scientific Drilling at Lake Tanganyika, Africa: A Transformative Record for Understanding Evolution in Isolation and the Biological History of the African Continent, University of Basel, 6–8 June 2016

Abstract

Abstract. We report on the outcomes of a workshop held to discuss evolutionary biology, paleobiology and paleoecology questions that could be addressed by a scientific drilling project at Lake Tanganyika, the largest, deepest and oldest of the African Rift Valley lakes. Lake Tanganyika is of special significance to evolutionary biologists as it harbors one of the most spectacular endemic faunas of any lake on earth, with hundreds of unique species of fish, molluscs, crustaceans and other organisms that have evolved over the lake's long history. Most of these groups of organisms are known from fossils in short cores from the lake, raising the possibility that both body fossil and ancient DNA records might be recovered from long drill cores. The lake's sedimentary record could also provide a record of African terrestrial ecosystem history since the late Miocene. This 3-day workshop brought together biological and geological specialists on the lake and its surroundings to prioritize paleobiological, ecological and microbiological objectives that could ultimately be incorporated into an overall drilling plan for Lake Tanganyika and to consider how biological objectives can effectively be integrated into the paleoclimate and tectonics objectives of a Lake Tanganyika drilling project already considered in prior workshops.

Evolutionary time and species diversity in aquatic ecosystems worldwide

“…Fossils preserved in sediment cores can even provide a direct window into the history of community assembly in ancient lakes. For example, a Lake Tanganyika or Lake Baikal drilling project could provide insights into the dynamics of ostracod species richness over timescales of hundreds of thousands to millions of years (Cohen & Salzburger, 2017). What explains patterns of species richness in ‘rule‐breaking’ clades, such as east African cichlids or Lake Baikal's amphipod and ostracod species flocks?…”

ICDP workshop on the Lake Tanganyika Scientific Drilling Project: a late Miocene–present record of climate, rifting, and ecosystem evolution from the world's oldest tropical lake

“…Participants emphasized the importance of determining LT's age and early conditions, and the transformative nature of a Miocene-present paleoclimate record from the tropics. Subsidence and sedimentation rate estimates suggest the Nyanja Event occurred between 9 and 12 Ma (Cohen et al, 1993). Accordingly, sequences S1 and S2 could date to the Miocene and Pliocene, and S3-S6 to the Pleistocene and Holocene.…”

“…During this season, strong southerly winds associated with the East African and Indian monsoons flow over the basin and cause lake upwelling that drives primary production by algae, especially diatoms, forming the basis for a fishery that has yielded up to ∼ 200 000 t of fish annually (Descy et al, 2005), one of the largest inland fisheries in the world. All of these components of LT vary in response to climate, as documented in intricate detail by geochemical and fossil records in shallow sediment cores (Cohen and Salzburger, 2017;Tierney and Russell, 2007). Lake Tanganyika is part of East Africa's western rift (Rosendahl, 1987;Ebinger, 1989).…”

“…Drilling LT offers outstanding opportunities to investigate evolutionary transitions in aquatic and terrestrial organisms and ecosystems, and the geological evolution of a large continental rift system. In the last 6 years we have convened a series of disciplinary workshops that developed a strong consensus that drilling LT will transform our understanding of climatic, evolutionary, and rift processes (Cohen and Salzburger, 2017;McGlue and Scholz, 2016;Russell et al, 2012). To expand on these objectives, and to develop a fully integrated, interdisciplinary scientific drilling program on Lake Tanganyika, we held an ICDP workshop in Dar es Salaam, Tanzania, from 17 to 20 June 2019, attended by more than 70 scientists.…”

Reconstructing the Environmental Context of Human Origins in Eastern Africa Through Scientific Drilling

“…Third, hopefully in the near future we can expect much longer records of African environmental history to be obtained from lake beds, spanning the entire 8-6 Ma time frame of hominin evolution. Projects in advanced stages of development from the oldest African lakes, Lakes Tanganyika (Cohen & Salzburger 2016, Russell et al 2020 and Chad (Sylvestre et al 2018), promise to provide records of African paleoclimate and ecosystem history since the Late Miocene from two very different regions of the continent (Figure 2). Along with other possible future drilling sites in other African Great Lakes, we anticipate these long records will yield tremendous advances in the emerging science of using scientific drilling to further our understanding of the deep-time environmental history of our distant ancestors.…”