Details zur Publikation

Referenztyp Zeitschriften
DOI / URL
Titel (primär) Indication of temperature inverted microbial assimilative capacities (extracellular enzyme activities) in the pelagic of Lake Sevan (Armenia)
Autor Minasyan, A.; Karrasch, B.;
Journal / Serie Lakes Reservoirs and Ponds
Erscheinungsjahr 2016
Department FLOEK;
Band/Volume 10
Heft 1
Sprache englisch;
POF III (gesamt) T32;
Keywords freshwater alpine lakes; Lake Sevan; climate change; eutrophication; temperature; bacteria; extracellular enzymatic activity
UFZ Querschnittsthemen RU2;
Abstract Pioneering records of extracellular enzymes activities (EEA) in Lake Sevan waters highlight dependence of heterotrophic functioning on physicochemical characteristics and bacterial assemblage. Values of EEA, ranged 0.11-30.39 µg C/P L-1h-1, were higher in upper layers compared to the omission in deeper parts. Particles associated (ecto-) enzymes mainly predominated over free dissolved (exo-) enzymes. In June activities of all studied enzymes followed similar pattern, particularly, decreasing at thermocline and increasing twice/more in cold deeper waters. Regardless higher bacterial density and temperature in June, with no similar records up to now, EEA revealed reverse relationship to temperature and bacteria data and were significantly lesser than in March. Our finding might be suggested as temperature inverted impact to heterotrophic activities in eutrophic conditions. We assume that observed, with temperature raise, declined EEA was due to blocked enzymatic active center from colloids and DOM components interaction, which, in overall, may suppress organic substrate utilization and result in weakening of first and rate limiting step of biological self-purification in Lake Sevan waters. Therefore, since temperature is co-regulator of assimilative/carrying capacity of aquatic ecosystems, climate warming might have unexpected negative feedbacks also through lowering assimilative capacities of water bodies, jeopardizing their quality and ecology.
ID 18139
dauerhafte UFZ-Verlinkung https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=18139
Minasyan, A., Karrasch, B. (2016):
Indication of temperature inverted microbial assimilative capacities (extracellular enzyme activities) in the pelagic of Lake Sevan (Armenia)
Lakes Reservoirs and Ponds 10 (1), 51 - 70