Mittwoch, 22. Oktober 2014, 18:15 - 20:00 iCal

Geographisches Kolloquium-Martin Kainz PhD

Biomarker research in aquatic food webs - Lessons from the subarctic to the tropics

NIG, Hs. 5A
Universitätsstr. 7/5, 1010 Wien


Trophic biomarkers indicate which dietary sources are retained in consumers by

using fairly inert biochemical tracers. Trophic transfer of organic matter is increasingly

evaluated using fatty acids by assuming that their dietary supply is somewhat

conservatively retained in consumers. I will present results Subartic,

pre-alpine and tropical aquatic ecosystems that identied relationships between

primary producers to their subsequent consumers. Dietary fatty acids ow across

this plant-animal interface was most ecient in both lake and uvial systems,

whereas sh (cyprinids and salmonids) retain the omega-3 polyunsaturated fatty

acids (PUFA) docosahexaenoic acid (DHA) most eciently, even if dietary DHA

supply is minimal. Fish feeding on PUFA-poor food show enzymatic conversion of

PUFA via enhanced hepatocytic desaturase and elongase activities. Similarity

measures between fatty acids in diets and consumers reveal consumers at all

trophic levels to act as 'integrators' by condensing the dietary variability of fatty

acids. These results suggest that zooplankton and sh from subarctic to tropical

aquatic ecosystems have a strong innate ability to convert dietary precursors into

target PUFA that they physiologically depend on. Yet, freshwater consumers are

able to selectively retain specic fatty acids in many freshwater consumers of

aquatic ecosystems worldwide.

Martin Kainz ist aquatischer Nahrungsnetzforscher und Ökotoxikologe. Er forscht

am inter-universitären Zentrum für aquatische Ökosystemforschung in Lunz am

See. Sein derzeitiges Forschungsfeld beinhaltet Fragen der Synthese essentieller

Fettsäuren und Bioakkumulation von Schadstoen in Wasserlebewesen in

Flüssen und Seen in der Arktik bis zu den Tropen. Er lehrt an der Universität Wien.


Institut für Geographie und Regionalforschung der Universität Wien


Aleksandra Tyjan
Institut für Geographie und Regionalforschung