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Response of Lake Kivu stratification to lava inflow and climate warming
Author(s) -
Lorke Andreas,
Tietze Klaus,
Halbwachs Michel,
Wüest Alfred
Publication year - 2004
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.2004.49.3.0778
Subject(s) - lava , stratification (seeds) , volcano , water column , geology , inflow , turbidity , population , environmental science , global warming , atmospheric sciences , climate change , oceanography , physical geography , climatology , hydrology (agriculture) , geochemistry , geography , seed dormancy , botany , germination , demography , geotechnical engineering , dormancy , sociology , biology
During the eruption of Nyiragongo Volcano in January 2002 about 10 6 m 3 of lava entered Lake Kivu. The high concentrations of CO 2 and CH 4 dissolved in the deep waters of Lake Kivu raised serious concerns about a potential gas outburst with catastrophic consequences for the population in the Kivu‐Tanganyika region. Therefore, 3 weeks after the volcanic eruption, we performed an ad hoc lake survey of the stability of the water column stratification. Vertical profiles of temperature and turbidity revealed signatures of the lava, which had penetrated to 100 m depth; however, there was no substantial warming or destratification of the gas‐containing deep layers below. The deep double‐diffusive structures also remained unaltered. Based on these observations, we conclude that a thermally driven gas outburst in Lake Kivu is not to be expected from future eruptions of comparable dimensions. In addition, the recent measurements allowed for an update and gave new insight into the stratification and double‐diffusive mixing phenomena in Lake Kivu. A comparison with former measurements revealed a warming of the upper part of the lake of up to 0.5°C within the last 30 yr, which could be attributed to climate variability.