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Doctoral defence in Biology - Agnes-Katharina Kreiling

Mon, 19/10/2020 - 14:00 to 16:00


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Ph.D. student: Agnes-Katharina Kreiling

Dissertation title: Invertebrate diversity in Icelandic freshwater springs

Opponents: Dr. Stefanie von Fumetti, Research Associate at the University of Basel, Switzerland.
Dr. Benjamin Price, Senior Curator in Entomology, Natural History Museum, London, UK.

Department coordinator: Dr. Snæbjörn Pálsson, Professor at the Faculty of Life and Environmental Sciences, University of Iceland

Advisor: Dr. Bjarni K. Kristjánsson, Professor at Hólar University

Doctoral committee: 
Dr. Jón S. Ólafsson, Limnologist at the Marine and Freshwater Research Institute
Dr. Eoin J. O’Gorman, Lecturer at the University of Essex, UK
Dr. Árni Einarsson, Director of the Mývatn Research Station

Chair of Ceremony: Dr. Anna Dóra Sæþórsdóttir, Professor and the Head of the Faculty of Life and Environmental Sciences, University of Iceland

Freshwater springs are thermally stable environments which are largely unaffected by changes in air temperature. They could thus have the potential to buffer rising temperatures and serve as small-scale refugia for aquatic invertebrates in a warming world.

 To better understand what environmental variables drive invertebrate diversity and community composition on springs in Iceland, an extensive field survey was conducted.
Due to rifts in the tectonic plates, large parts of Iceland are of volcanic origin and geothermally active. Thus, a high number of freshwater springs can be found along the edges of the porous lava fields, ranging in temperature from 2°C to boiling hot. Springs also differ in other characteristics, e.g. altitude, spring type, substrate and vegetation density.

An invertebrate community of 49 springs were studied on a spatial scale and one of them followed throughout a year to analyse temporal variability.

The most abundant invertebrate groups in Icelandic springs were Chironomidae (Diptera), followed by Ostracoda and Copepoda. One of the main drivers of community composition was temperature, resulting in a distinct species group characteristic for hot springs. Additionally, spring type and geographical position influenced communities. Community composition also differed on a temporal scale within the same spring, with distinctions between summer and winter community. This seasonality in the invertebrate community was unaffected by temperature changes but had implications on the apex predator in the system, Arctic charr.

The results of this thesis give some insight into Icelandic spring ecosystems and will contribute to conservation of these unique habitats.

About the doctoral candidate:

Agnes-Katharina Kreiling got a Diploma degree in Biology from the University of Freiburg, Germany in 2013. She is currently working at the Marine and Freshwater Research Institute in Iceland and lives in Kópavogur. She is married to Leivur Janus Hansen.

Agnes-Katharina Kreiling

Doctoral defence in Biology - Agnes-Katharina Kreiling