MICKI project – Microbial diversity and processes in Lake Kivu

KIVU1Lake Kivu, located in Eastern Africa, is a meromictic tropical lake with a relatively shallow euphotic layer (~18m) usually smaller than its oxic mixolimnion (20-60 m), and with a weak thermal gradient in the mixolimnion. Lake Kivu has unique limnological characteristics, with temperature and salinity increasing in the deep water layers, due to the input of geothermal sources at the bottom of the lake. The deep monimolimnion is rich in dissolved gases, particularly carbon dioxide (CO2) and methane (CH4).KIVU3

The objective of the MICKI project is to determine the contribution of different microbial (bacteria/archaea) communities to specific biogeochemical processes in Lake Kivu and to investigate how the different microbial players affect nutrient dynamics and ecosystem productivity. Besides the heterotrophic bacteria and those involved in methane oxidation (methanotrophs), the presence of a well-defined redoxcline provides an optimal niche for the development of ammonia oxidizing archaea AOA, ammonia oxidizing bacteria (AOB), anaerobic ammonia oxidizing (anammox) bacteria and Green Sulfur Bacteria (GSB) populations. The microbial community composition is explored in a depth gradient in parallel with processes measurements (methane oxidation, nitrification, denitrification, S oxidation and reduction).

 

KIVU2

Sampling effort are done to capture the possible stratification of bacterial community, especially in the redoxcline. The lake is sampled at different periods of the year to obtain information about the seasonal variations as well.

 

MICKI partners:

COU-ULg (Borges, A., Darchambeau, F.), ESA-ULB (Servais, P.), URBE-FUNDP (Descy, J.P.). 

Collaboration with:

Universitat Autonoma de Barcelona (Lliros, M.), KUL (Bouillon, S., Morana, C.), British Columbia University, Canada (Crowe, S.)

ESA members participating to MICKI:

Servais, P., Inceoglu, O., Garcia-Armisen, T., Michiels, C., Vanderschueren, S.

Period of the study:

January 2011- December 2013.

Financial support:

FNRS – Fonds de la Recherche Scientifique (Belgium) (http://www.fnrs.be/)

Master thesis performed in the scope of MICKI:

Michiels, C. 2012. Stratification verticale des communautés microbiennes du Lac Kivu (Afrique de l’Est).

Vanderschueren, S. 2013. Etude des communautés bactériennes présentes et actives au lac Kivu (Afrique de l’Est)

Publications:

İnceoglu O, Lliros M, Crowe SA, Garcia-Armisen T, Morana, C., Darchambeau F, Borges A, Descy JP and Servais P. 2015. Vertical distribution of functional potential and active microbial community composition in meromictic Lake Kivu. Microbial Ecology.  DOI: 10.1007/s00248-015-0612-9

Inceoglu, O., Lliros, M., Garcia-Armisen, T., Crowe, S.A., Michiels, C., Darchambeau, F., Descy, J.P. & Servais,P. 2015. Distribution of bacterial and archaeal communities in meromictic tropical Lake Kivu (Africa). Aquatic Microbial Ecology. 74: 215-233

Borges, A., Morana, C., Bouillon, S., Servais, P., Descy, J.P. & Darchambeau, F. 2014. Carbon cycling of Lake Kivu (East Africa): net autotrophy in the epilimnion and emission of CO2 to the atmosphere sustained by geogenic inputs. Plos One. 9(10): e109500

Borges A.V., Bouillon, S., Abril, G., Delille, B. Poirier, D., Commarieu, M.V., Lepoint, G., Morana, C., Champenois, W., Servais, P., Descy, J.P. & Darchambeau, F.  2012. Variability of carbon dioxide and methane in the epilimnion of Lake Kivu In Lake Kivu: Limnology and biogeochemistry of a tropical great lake (Descy, J.P., Darchambeau, F., Schmid, M., Eds)

Lliros, M., Descy, J.P., Libert, X. Morana, C., Schmitz, M., Wimba, L., Nzavuga-Izere, A., Garcia-Armisen, T., Borrego, Servais, P.  & Darchambeau, F. 2012. Microbial ecology of Lake Kivu. In Lake Kivu: Limnology and biogeochemistry of a tropical great lake  (Descy, J.P., Darchambeau, F., Schmid, M., Eds) Aquatic Ecology Series, Springer. Chapter 6: 85-106.