Details zur Publikation

Referenztyp Zeitschriften
DOI / URL Link
Titel (primär) Ecomicrobiology and microbial assimilative capacity of the oligotrophic Andean Lake Laja, Chile
Autor Karrasch, B.; Woelfl, S.; Urrutia, R.; González, J.; Valdovinos, C.; Cid, H.; Parra, O.;
Journal / Serie Revista Chilena de Historia Natural
Erscheinungsjahr 2011
Department FLOEK;
Band/Volume 84
Heft 3
Sprache englisch;
Keywords bacterioplankton; extracellular enzymes; heterotrophic fl agellates; N-limitation; phytoplankton
Abstract

A strong socio-economic development pressure in South Chile will more and more cause an impact to the present lakes and rivers. Nevertheless, our knowledge concerning the ecological structure and the microbial self-purification capabilities of these lacustrine water bodies is scant but essential for a future sustainable development of land and water use. We studied Lake Laja, a lake already heavily impacted by water diversions for hydropower generation and irrigation. Typical for the Andean region Lake Laja is an oligotrophic water body, limited by nitrogen nutrients. Only very low chlorophyll a and particulate organic carbon (POC) concentrations and a small abundance and biomass of bacteria (mainly ultramicrobacteria) and heterotrophic fl agellates were encountered. Weak trophic interrelations were derived from a high bacteria-to-heterotrophic fl agellate ratio. For the ten investigated extracellular enzymes (alkaline phosphatase, leucine-, arginine-, glycine- and tyrosine-aminopeptidase, α-, β-D-glucosidase, α-, β-D-galactosidase, N-acetyl-β-D-glucosaminidase), with the exception of α-D-glucosidase, a broad range of organic matter degradation activities was proven. Probably, due to the N-limitation, organic nitrogen hydrolysing extracellular enzymes reached activities on average of 45 % compared to other studies in oligotrophic waters. The possible effect of N-limitation on extracellular enzyme activities was more pronounced by cell specifi c extracellular enzymatic activity rates, which exceeded those of other oligotrophic water bodies on average by factor 2. The overall activities of all microbial extracellular enzymes studied proved to be dominated by the dissolved free external enzymes (up to 98 %) over the ectoenzymes which are associated with particulate organic matter (bacterial cell walls, particles, and aggregates). It is concluded that future socio-economic changes, dealing with watershed human intervention (accelerating inorganic and organic loads) as well as global change (temperature and precipitation changes) could lead to significant changes in the ecology of Lake Laja.
ID 11939
dauerhafte UFZ-Verlinkung https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=11939
Karrasch, B., Woelfl, S., Urrutia, R., González, J., Valdovinos, C., Cid, H., Parra, O. (2011):
Ecomicrobiology and microbial assimilative capacity of the oligotrophic Andean Lake Laja, Chile
Rev. Chil. Hist. Nat. 84 (3), 433 - 450