New knowledge about life in the sea ice
Top image: The life historiy of Onisimus litoralis is described in detail in a new PhD thesis. Photo: Henrik Nygård/UNIS.
PhD candidate Henrik Nygård has studied the ecological traits and adaptations of benthic amphipods in the High Arctic. His findings also provide unprecedented insights into the life and ecology of related species living in ice infested waters. Nygård will defend his PhD thesis at UNIS on 2 May 2011.
28 April 2011
Press release from UNIS and University of Tromsø
The Arctic sea ice ecosystem is among least understood and fastest changing systems on the planet. By using ecological comparative methods, Henrik Nygård presents in his PhD thesis data from more easily accessible benthic species that ultimately provide vital knowledge on ice associated species.
Nygård’s study on ecological traits and adaptations of benthic amphipods provides much needed knowledge of the benthic organisms themselves, but ultimately also provide unprecedented insights into the life and ecology of their sibling species living in connection to sea ice.
Data collection at 80°N
Nygård’s data collection was obtained through year-round sampling in two climatically different Arctic fjords in Svalbard, Adventfjorden outside Longyearbyen (78°N), and Rijpfjorden, on the northern coast of Nordaustlandet (80°N). He sampled shallow water amphipod scavenging species, with emphasis on Onisimus– and Anonyx-species.
In his thesis, Nygård describes in detail the life histories of two common species, Onisimus litoralis and O. caricus, related to environmental conditions. Based on this knowledge new ideas about the ecology of the sea ice associated sibling species O. nanseni and O. glacialis are discussed.
Also the feeding preferences of the scavenging amphipods were studied by means of fatty acid and stable isotope analyses. Three conspicuous feeding modes were identified among the four Onisimus-species. A seasonal pattern in the amphipods’ attraction to bait was observed and is related to food availability and development of the amphipods. The role of sea ice as a temporary habitat for the benthic species was also studied.
Henrik Nygård will defend his PhD thesis “Scavenging amphipods in the high Arctic; Studies of benthic and sympagic amphipods in the genera Onisimus and Anonyx” at UNIS on 2 May 2011 at 12:15. The candidate will give a trial lecture called “Acclimation and adaptation of crustaceans in estuarine systems with focus on behavior, physiology and life history”, on 2 May at 10:15.
About the candidate:
Henrik Nygård (born in 1979 in Finland) completed his Master’s degree in Environmental and Marine Biology at Åbo Akademi University, Turku, Finland in 2005.
In January 2007 he enrolled as a PhD student at the University Centre in Svalbard (UNIS) and the University in Tromsø.