Dziani Dzaha Lake Targeted loci environmental. Dziani Dzaha Lake

Dziani Dzaha is a small, tropical volcanic crater lake located in Mayotte Island. This lake isalkaline, hypersaline with permanent anoxia below one meter depth and characterized by ahigh productivity with a low biomass turnover rate. Water chemistry of the lake supports thehypothesis of the marine origin of water strongly modified by geological (bubbling ofvolcanic CO2 and possibly hydrothermal imputs) and microbial activities, which togethergenerated the mild alkaline conditions observed (pH close to 9). This saline lake thusrepresents a unique environmental end member, which may have been more common in thepast, in particular at times of the deposition of lacustrine source rocks and to some extent attimes of ocean anoxic events. The objective of this proposal is to characterize the prokaryoticdiversity of the subsurface of this unique ecosystem, first step towards addressing their rolesin the biogeochemical cycles within the lake. PI: Helene Agogue, [e-mail]