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Research interests:

My current research focus on eelgrass (Zostera marina) ecosystems:

  • ecosystem function, with special emphasis on crustacean and gastropod mesograzers
  • biodiversity of meio- and macrofauna within the sediment and epiphytes and epifauna on the leaves.
  • molecular characterization of meiofauna in eelgrass bed

These studies involves field experiments with grazer exclusion and habitat manipulations, molecular barcoding and environmental sequencing, as well as a lot taxonomic identification by stereo-, light- and scanning electron microscopy.

I furthermore have a background working with very different groups of marine life:

  • Kinorhyncha (muddragons) - taxonomy, systematics, and selected external and internal ultrastructures within this meiofaunal marine phylum.
  • Ice-associated (sympagic) amphipods - taxonomy and ecology
  • Hagfish taxonomy
  • Rhodoliths (unattached calcified red algae) – formation, ecology and faunal biodiversity

These studies have involved a large amount of Arctic field work, and provided me with extensive skills in microscopical methods (Stereo, Light, Scanning Electron, and Confocal Laser Scanning Microscopy), taxonomy, systematic and ecology. 


Higher education

  • 2010 M.Sc. in Marine Biology, Zoological Museum, University of Copenhagen. 


  • “Dyppvannsfauna i norske farvann" from The Norwegian Academy of Science and Letters. For barcoding of polychaetes (2011)
  • “Carlsbergs Mindelegat” for participation in the Danish Galathea 3 expedition (2006)
  • “Hotelejer Anders Månsson og Hustrus mindelegat” for studies at James Cook University, Australia (2005).
  • “Internationaliseringsstipendium”, University of Copenhagen,  for studies at James Cook University, Australia (2005)
  • “Nordlys Stipendium” for studies at UNIS – the University Centre in Svalbard (2004)


Tags: Zoology, Eelgrass, Taxonomy, Meiofauna, Marine biology, Environmental sequencing, Biology, Ecosystems, Marine ecology


Silberberger M, Thormar J, Fredriksen S (2016) Small scale removal of seagrass (Zostera marina L.): Effects on the infaunal community. Marine Biology Research. DOI:10.1080/17451000.2016.1225959

Thormar J, Hasler-Sheetal H, Baden S, Boström C, Clausen KK, Krause-Jensen D, Olesen B, Rasmussen JR, Svensson CJ, Holmer M (2016) Local environmental state regulates eelgrass (Zostera marina) food web structure. PLoS ONE 11(1): e0146479 DOI:10.1371/journal.pone.0146479

Duffy JE, Reynolds P, Boström C, Coyer J, Cusson M, Donadi S, Douglass J, Engelen A, Eriksson BK, Fredriksen S, Gamfeldt L, Gustafsson C, Hoarau G, Hori M, Hovel K, Iken K, Lefcheck J, Moksnes P‐O, Nakaoka M, O'Connor M, Olsen J, Richardson JP, Ruesink J, Sotka E, Thormar J, Whalen M, Stachowicz J. (2015) Biodiversity mediates top‐down control in eelgrass ecosystems: A global comparative‐experimental approach. Ecology Letters 18:696-705 DOI:10.1111/ele.12448

Herranz M, Thormar J, Benito J, Sánchez N, Pardos F (2012) Meristoderes gen. nov., a new kinorhynch genus, with the description of two new species and their implications for echinoderid phylogeny (Kinorhyncha: Cyclorhagida, Echinoderidae). Zoologischer Anzeiger 251:161-179 DOI:10.1016/j.jcz.2011.08.004

Sørensen MV & Thormar J (2010) Wollunquaderes majkenae gen. et sp. nov. - a new cyclorhagid kinorhynch genus and species from the Coral Sea, Australia. Marine Biodiversity, 40:261-275. DOI:10.1007/s12526-010-0048-x

Thormar J & Sørensen MV (2010). Two new species of Echinoderes (Kinorhyncha: Cyclorhagida) from the Solomon Islands. Meiofauna Marina 18:67-96.

Falk-Petersen S, Leu E, Berge J, Kwasniewski S, Nygård H, Røstad A, Keskinen E, Thormar J, Quillfeldt C, Wold A, Gulliksen B (2008) Vertical migration in high Arctic waters during autumn 2004. Deep Sea Research Part II - Topical Studies in Oceanography 55:2275–2284. DOI:10.1016/j.dsr2.2008.05.010

Thormar J (2008) The Rhodoliths of Disko Fjord, Greenland: First visual record of the Litothamnion glaciale/tophiforme (Corallinales, Rhodophyta) aggregation in Disko Fjord, 69°N, Greenland“ In: Halberg KA (ed) Arctic Biology Field Course, Qeqertarsuaq, 2006. Institute of Biology, University of Copenhagen. ISBN 87-87519-67-4.

Macnaughton MO, Thormar J, Berge J (2007) Sympagic amphipods in the Arctic pack ice: redescriptions of Eusirus holmii Hansen, 1887 and Pleusymtes karstensi (Barnard, 1959). Polar Biology, 30:1013-1025. DOI: 10.1007/s00300-007-0260-8

Møller PR, Feld TK, Poulsen IH, Thomsen PF, Thormar JG (2005) Myxine jespersenae, A New Species of Hagfish (Myxiniformes: Myxinidae) from the North Atlantic Ocean. Copeia (American Society of Ichthyologists and Herpetologists), 2005(2):274-285

Christoffersen K, Thormar J, Bille-Hansen R (2005). Biological state of arctic lakes and ponds on Disko Island, Greenland. In: Arctic fieldcourse 2004. Institute of Biology, University of Copenhagen. ISBN 87-987317-2-6.

Keskinen E, Leu E, Nygård H, Røstad A, Thormar J (2004). New findings of diel vertical migration in high Arctic ecosystems. In: Berge J (ed) AB320-2004. UNIS Publication Series ISSN 1503-4410.


Macnaughton, Thormar, Kielland (2012). Livet under overfladen. Gyldendal. ISBN: 9788702098945. 288p.

  • Silberberger, Marc Jürgen; Thormar, Jonas & Fredriksen, Stein (2016). Small-scale removal of seagrass (Zostera marina L.): effects on the infaunal community. Marine Biology Research.  ISSN 1745-1000.  12, s 993- 1002 . doi: 10.1080/17451000.2016.1225959
  • Thormar, Jonas; Hasler-Sheetal, Harald; Baden, Susanne; Boström, Christoffer; Clausen, Kevin Kuhlmann; Krause-Jensen, Dorte; Olesen, Birgit; Rasmussen, Jonas Ribergaard; Svensson, Carl Johan & Holmer, Marianne (2016). Eelgrass (Zostera marina) food web structure in different environmental settings. PLoS ONE.  ISSN 1932-6203.  11(1) . doi: 10.1371/journal.pone.0146479
  • Duffy, J. Emmett; Reynolds, Pamela L.; Boström, Christoffer; Coyer, James A.; Cusson, Mathieu; Donadi, Serena; Douglass, James G.; Eklöf, Johan S.; Engelen, Aschwin H.; Eriksson, Britas Klemens; Fredriksen, Stein; Gamfeldt, Lars; Gustafsson, Camilla; Hoarau, Galice; Hori, Masakazu; Hovel, Kevin; Iken, Katrin; Lefcheck, Jonathan S.; Moksnes, Per-Olav; Nakaoka, Masahiro; O'Connor, Mary I.; Olsen, Jeanine L.; Richardson, J. Paul; Ruesink, Jennifer L.; Sotka, Erik E.; Thormar, Jonas Gjaldbæk; Whalen, Matthew A. & Stachowicz, John J. (2015). Biodiversity mediates top-down control in eelgrass ecosystems: a global comparative-experimental approach. Ecology Letters.  ISSN 1461-023X.  18(7), s 696- 705 . doi: 10.1111/ele.12448
  • Herranz, María; Thormar, Jonas; Benito, Jesús; Sánchez, Nuria & Pardos, Fernando (2012). Meristoderes gen. nov., a new kinorhynch genus, with the description of two new species and their implications for echinoderid phylogeny (Kinorhyncha: Cyclorhagida, Echinoderidae). Zoologischer Anzeiger.  ISSN 0044-5231.  251(3), s 161- 179 . doi: 10.1016/j.jcz.2011.08.004
  • Falk-Petersen, Stig; Leu, Eva; Berge, Jørgen; Kwasniewski, Slawomir; Nygård, Henrik; Røstad, Anders; Keskinen, Essi; Thormar, Jonas; von Quillfeldt, Cecilie; Wold, Anette & Gulliksen, Bjørn (2008). Vertical migration in high Arctic waters during autumn 2004. Deep-sea research. Part II, Topical studies in oceanography.  ISSN 0967-0645.  55(20-21), s 2275- 2284 . doi: 10.1016/j.dsr2.2008.05.010 Show summary
  • Macnaughton, Martin; Thormar, Jonas & Berge, Jørgen (2007). Sympagic amphipods in the Arctic pack ice: redescriptions of Eusirus holmii Hansen, 1887 and Pleusymtes karstensi (Barnard, 1959). Polar Biology.  ISSN 0722-4060.  30(8), s 1013- 1025 . doi: 10.1007/s00300-007-0260-8 Show summary

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  • Bekkby, Trine; Sigurd, Espeland; Dolan, Margaret; Rinde, Eli; Moy, Frithjof Emil; Elvenes, Sigrid; Gundersen, Hege; van Son, Thijs Christiaan; Sogn Andersen, Guri; Thormar, Jonas; Frigstad, Helene; Moy, Siri Røang; Beylich, Bjørnar; Albretsen, Jon; Naustvoll, Lars Johan & Tveiten, Lise Ann (2018). Pilotprosjekt - Kartlegging av marin natur i Møre og Romsdal. Årsrapport 2017. Full text in Research Archive.
  • Thormar, Jonas (2017). Disturbance and trophic interactions in Scandinavian eelgrass ecosystems. Series of dissertations submitted to the Faculty of Mathematics and Natural Sciences, University of Oslo.. 1836.
  • Thormar, Jonas; Steen, Henning; van Son, Thijs Christiaan; Bosgraaf, Sebastian; Christensen, Lene; Mellerud, Ida Kristin; Moy, Frithjof Emil & Norderhaug, Kjell Magnus (2017). Fish Assemblages in Coastal Vegetation.
  • Andersen, A; Thormar, Jonas; Norderhaug, KM & Fredriksen, Stein (2013). Benthic communities at the opera in Bjørvika.
  • Falk-Petersen, Stig; Wold, A; Røstad, A; Leu, E; Nygård, H; Gulliksen, Bjørn; Berge, Jørgen; Keskinen, E; Thormar, J. Gjaldbæk & Kwasniewski, S (2004). Intense feeding of Calanus hyperboreus on Arctic Autumn Bloom Propagated by a Record Minimum Sea Ice Extent in 2004.

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Published Nov. 3, 2010 3:34 PM - Last modified Apr. 7, 2017 11:34 AM