Open AccessPhysical constraints in the deep hypolimnion of a subalpine lake driving planktonic Bacteria and Archaea distribution
Author(s) -
Roberto Bertoni,
Walter Ambrosetti,
Cristiana Callieri
Publication year - 2010
Publication title -
advances in oceanography and limnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.387
H-Index - 16
eISSN - 1947-573X
pISSN - 1947-5721
DOI - 10.4081/aiol.2010.5296
Subject(s) - hypolimnion , crenarchaeota , plankton , archaea , epilimnion , abundance (ecology) , environmental science , ecology , range (aeronautics) , prokaryote , habitat , water column , oceanography , geology , biology , eutrophication , bacteria , paleontology , materials science , nutrient , composite material
The study of the hydrodynamics of the hypolimnion of a deep holo-oligomictic lake (Lake Maggiore, Northern Italy, zmax¼370 m) during the last 28 years showed that hypolimnetic waters remained isolated, not exchanging with the mixing zone even in winter when the full overturn conditions are most likely. The thickness of the isolated layer can range from 100 to 300 m. Thus, water masses of variable size reside in the lake for many years, and their physical and chemical conditions remain relatively unaffected by seasonal variability and epilimnetic imputs. In the hypolimnetic waters prokaryote abundance is three times lower than in the mixing layer but cell size is significantly higher. In addition, the relative abundance of Archaea and Crenarchaeota increases with depth in respect to that of Bacteria. The heterogeneous distribution of the two domains within the habitat can be attributed to the existence in the same environment of isolated water masses