EESS talk on "'All carbon is equal, but some is more equal' – differences in dietary carbon utilization across food webs"
Event details
| Date | 16.05.2017 |
| Hour | 12:15 › 13:15 |
| Speaker |
Dr Martin Kainz, Group Leader, Aquatic Lipid Research and Ecotoxicology (LIPTOX) WasserCluster, Vienna University, Lunz am See (Austria) Short biography: Martin Kainz pursued his PhD in ecotoxicology and environmental sciences at the Université du Québec à Montréal, Canada, followed by post-docs at the University of Victoria, BC, and the Canadian National Water Research Institute, Burlington, ON. Since 2006 he works at the inter-university center for aquatic ecosystem research WasserCluster Lunz, Austria. His current research includes questions about food quality, animal development, trophic transfer efficiency, and dietary carbon composition. He is actively involved in several research networks, such as the Global Lake Ecological Observatory Network (GLEON) and the Alpine Limnology Network (LimnoAlp) in Europe. |
| Location | |
| Category | Conferences - Seminars |
Abstract:
Carbon is essential in providing dietary energy from the base to the top of all food chains. To date, most of the food web research evaluates the nutritional value of food on an elemental basis, including bulk C, N, P, and essential micronutrients such as Si, Ca, Mg, S, Fe, etc. The trophic fate and utilization of these dietary nutrients vary strongly among food webs and challenge food web scientists for a long time. In freshwater ecosystems, dietary organic matter is generally derived from terrestrial and autochthonous (algal) sources that differ in their biochemical composition. Terrestrial organic matter (t-OM) inputs to lakes and rivers are comprised of biochemically mostly recalcitrant lignocellulose that is highly resistant to enzymatic breakdown by animal consumers. Further, t-OM and heterotrophic bacteria lack essential biochemical compounds that are critical for rapid somatic growth and reproduction in aquatic invertebrates and fishes. However, amino acid stable isotope analyses for food webs indicate that most upper trophic level essential amino acids are derived from algae. Similarly, profiles of essential fatty acids in consumers show a strong dependence on algal food resources. I will present evidence that the relative importance of t-OM subsidies for upper trophic level production should be addressed by considering the rates at which terrestrial and autochthonous resources are consumed and the growth efficiency supported by this food. Ultimately, the biochemical composition of a particular basal resource, and not just its quantity or origin, determines how readily this material is incorporated into upper trophic level consumers. Because of the highly favorable biochemical composition and greater availability, it can be concluded that algae-derived dietary energy supports most animal production in aquatic ecosystems.
Carbon is essential in providing dietary energy from the base to the top of all food chains. To date, most of the food web research evaluates the nutritional value of food on an elemental basis, including bulk C, N, P, and essential micronutrients such as Si, Ca, Mg, S, Fe, etc. The trophic fate and utilization of these dietary nutrients vary strongly among food webs and challenge food web scientists for a long time. In freshwater ecosystems, dietary organic matter is generally derived from terrestrial and autochthonous (algal) sources that differ in their biochemical composition. Terrestrial organic matter (t-OM) inputs to lakes and rivers are comprised of biochemically mostly recalcitrant lignocellulose that is highly resistant to enzymatic breakdown by animal consumers. Further, t-OM and heterotrophic bacteria lack essential biochemical compounds that are critical for rapid somatic growth and reproduction in aquatic invertebrates and fishes. However, amino acid stable isotope analyses for food webs indicate that most upper trophic level essential amino acids are derived from algae. Similarly, profiles of essential fatty acids in consumers show a strong dependence on algal food resources. I will present evidence that the relative importance of t-OM subsidies for upper trophic level production should be addressed by considering the rates at which terrestrial and autochthonous resources are consumed and the growth efficiency supported by this food. Ultimately, the biochemical composition of a particular basal resource, and not just its quantity or origin, determines how readily this material is incorporated into upper trophic level consumers. Because of the highly favorable biochemical composition and greater availability, it can be concluded that algae-derived dietary energy supports most animal production in aquatic ecosystems.
Practical information
- General public
- Free
- This event is internal
Organizer
- EESS - IIE
Contact
- Prof. Tom Battin, SBER