Microcrystalline sphalerite in resin globules suspended in Lake Kivu, East Africa

1972 ◽  
Vol 7 (1) ◽  
Author(s):  
E.T. Degens ◽  
H. Okada ◽  
S. Honjo ◽  
J.C. Hathaway
Keyword(s):  
East Africa ◽  
Lake Kivu

scholarly journals Missing atmospheric noble gases in a large, tropical lake: The case of Lake Kivu, East-Africa

2020 ◽  
Vol 532 ◽  
pp. 119374
Author(s):  
Fabian Bärenbold ◽  
Martin Schmid ◽  
Matthias S. Brennwald ◽  
Rolf Kipfer
Keyword(s):  
East Africa ◽  
Noble Gases ◽  
Tropical Lake ◽  
Lake Kivu

scholarly journals Nitrous oxide and methane seasonal variability in the epilimnion of a large tropical meromictic lake (Lake Kivu, East-Africa)

2016 ◽  
Vol 79 (2) ◽  
pp. 209-218 ◽  
Author(s):  
Fleur A. E. Roland ◽  
François Darchambeau ◽  
Cédric Morana ◽  
Alberto V. Borges
Keyword(s):  
Nitrous Oxide ◽  
East Africa ◽  
Seasonal Variability ◽  
Meromictic Lake ◽  
Lake Kivu

scholarly journals Chemoautotrophy and anoxygenic photosynthesis within the water column of a large meromictic tropical lake (Lake Kivu, East Africa)

2016 ◽  
Vol 61 (4) ◽  
pp. 1424-1437 ◽  
Author(s):  
Cédric Morana ◽  
Fleur A. E. Roland ◽  
Sean A. Crowe ◽  
Marc Llirós ◽  
Alberto V. Borges ◽  
...  
Keyword(s):  
Water Column ◽  
East Africa ◽  
Tropical Lake ◽  
Anoxygenic Photosynthesis ◽  
Lake Kivu

Monohydrocalcite in the sediments of Lake Kivu (East Africa)

Sedimentology ◽  
1974 ◽  
Vol 21 (1) ◽  
pp. 163-170 ◽  
Author(s):  
PETER STOFFERS ◽  
REINHARD FISCHBECK
Keyword(s):  
East Africa ◽  
Lake Kivu

scholarly journals Biogeochemistry of a large and deep tropical lake (Lake Kivu, East Africa): insights from a stable isotope study covering an annual cycle

2014 ◽  
Vol 11 (12) ◽  
pp. 17227-17254 ◽  
Author(s):  
C. Morana ◽  
F. Darchambeau ◽  
F. A. E. Roland ◽  
A. V. Borges ◽  
F. Muvundja ◽  
...  
Keyword(s):  
Organic Matter ◽  
Stable Isotope ◽  
East Africa ◽  
Mixed Layer ◽  
Seasonal Variability ◽  
Rainy Season ◽  
Dry Season ◽  
Tropical Lake ◽  
Particulate Nitrogen ◽  
Lake Kivu

Abstract. During this study, we investigated the seasonal variability of the concentration and the stable isotope composition of several inorganic and organic matter reservoirs in the large, oligotrophic and deep tropical Lake Kivu (East Africa). Data were acquired during one year at a fornightly temporal resolution. The δ13C signature of the dissolved inorganic carbon (DIC) increased linearly with time during the rainy season, then suddenly decreased during the dry season due to vertical mixing with δ13C-depleted DIC waters. This pattern reflects the net autotrophic status of the mixed layer of Lake Kivu, contrary to the common observation that oligotrophic aquatic ecosystems tend to be net heterotrophic. The δ13C signature of the particulate organic carbon pool (POC) revealed the presence of a consistently abundant methanotrophic biomass in the oxycline throughout the year. We also noticed a seasonal shift during the dry season toward higher values in the δ15N of particulate nitrogen (PN) in the mixed layer and δ15N-PN was significantly related to the contribution of cyanobacteria to the phytoplankton assemblage, suggesting that rainy season conditions could be more favourable to atmospheric nitrogen-fixing cyanobacteria. Finally, zooplankton were slightly enriched in δ13C compared to the autochtonous POC pool, and the δ15N signature of zooplankton followed well the seasonal variability in δ15N-PN, being consistently 3.0 ± 1.1‰ heavier than the PN pool. Together, δ13C and δ15N analysis suggests that zooplankton directly incorporate algal-derived organic matter in their biomass, and they would rely almost exclusively on this source of organic matter throughout the year in general agreement with the very low allochthonous organic matter inputs from rivers in Lake Kivu.

scholarly journals 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 ◽  
2014 ◽  
Vol 9 (10) ◽  
pp. e109500 ◽  
Author(s):  
Alberto V. Borges ◽  
Cédric Morana ◽  
Steven Bouillon ◽  
Pierre Servais ◽  
Jean-Pierre Descy ◽  
...  
Keyword(s):  
Carbon Cycling ◽  
East Africa ◽  
Lake Kivu

scholarly journals Biogeochemistry of a large and deep tropical lake (Lake Kivu, East Africa: insights from a stable isotope study covering an annual cycle

2015 ◽  
Vol 12 (16) ◽  
pp. 4953-4963 ◽  
Author(s):  
C. Morana ◽  
F. Darchambeau ◽  
F. A. E. Roland ◽  
A. V. Borges ◽  
F. Muvundja ◽  
...  
Keyword(s):  
Stable Isotope ◽  
East Africa ◽  
Seasonal Variability ◽  
Rainy Season ◽  
Dissolved Inorganic Carbon ◽  
Dry Season ◽  
Tropical Lake ◽  
Particulate Nitrogen ◽  
Δ13c And Δ15n ◽  
Lake Kivu

Abstract. During this study, we investigated the seasonal variability of the concentration and the stable isotope composition of several inorganic and organic matter (OM) reservoirs in the large, oligotrophic and deep tropical Lake Kivu (East Africa). Data were acquired over 1 year at a fortnightly temporal resolution. The δ13C signature of the dissolved inorganic carbon (DIC) increased linearly with time during the rainy season, then suddenly decreased during the dry season due to vertical mixing with 13C-depleted DIC waters. The δ13C signature of the particulate organic carbon pool (POC) revealed the presence of a consistently abundant methanotrophic biomass in the oxycline throughout the year. We also noticed a seasonal shift during the dry season toward higher values in the δ15N of particulate nitrogen (PN) in the mixed layer and δ15N-PN was significantly related to the contribution of cyanobacteria to the phytoplankton assemblage, suggesting that rainy season conditions could be more favourable to atmospheric nitrogen-fixing cyanobacteria. Finally, zooplankton were slightly enriched in 13C compared to the autochthonous POC pool, and the δ15N signature of zooplankton followed well the seasonal variability in δ15N-PN, consistently 3.0 ± 1.1 ‰ heavier than the PN pool. Together, δ13C and δ15N analysis suggests that zooplankton directly incorporate algal-derived OM in their biomass, and that they rely almost exclusively on this source of OM throughout the year in general agreement with the very low allochthonous OM inputs from rivers in Lake Kivu.

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