Áhrif gjóskufalls á götungasamfélög á hafsbotni - verkefni lokið

Fréttatilkynning verkefnisstjóra


The focal point of the TeMa project is the potential impact of volcanism on the marine ecosystem. 

 A short news release about the TeMa project


The focal point of the TeMa project is the potential impact of volcanism on the marine ecosystem. The project used selected Holocene tephras to test the hypothesis that tephra deposition on the sea floor can influence certain benthic foraminafera significantly and that changes in their abundance/ratio can be caused by volcanic events rather than changes in ocean currents and climate. Sediments on the North Icelandic shelf preserve a long, high resolution record of environmental changes. Sedimentation is controlled by oceanic currents, marine ecosystems, and terrestrial and volcanic input of sediments. In TeMa, benthic faunal assemblages, oxygen and carbon isotopes, and grain size of the sediment adjacent to selected, dated tephra layers were analysed in three sediment cores, MD99-2271, MD99-2272, and MD99-2275.  The results obtained with the TeMa project show that in areas with tephra air fall, benthic assemblages may be influenced by tephra fall events. This should be considered, when using Transfer Functions for salinity and temperature reconstructions based on benthic foraminifera. The species Elphidium excavatum forma clavata is generally related to salinity and temperature. However, this species also peaks in certain tephra layers (particularly basaltic tephras). Peaks in Elphidium excavatum also appear to be accompanied by an increase in carbon isotope values (benthic foraminifera) and increased grain size (caused by input of tephra). Further studies are needed to resolve whether these changes are caused by lack of nutrients or by changes in nutrient availability or changes in other chemical parameters.

Heiti verkefnis: Áhrif gjóskufalls á götungasamfélög á hafsbotni
Verkefnisstjóri: Jón Eiríksson, Jarðvísindastofnun Háskólans
Tegund styrks: Verkefnisstyrkur
Styrkár: 2010-2012
Fjárhæð styrks: 12,226 millj. kr. alls
Tilvísunarnúmer Rannís: 100218-02

Impacts and application

The ecological results of the TeMa project have been presented at international conferences, and anticipated publication in a peer reviewed journal will make the final results and interpretations available to the research community. Part of the tephrochronological work has already been published in peer reviewed journals and presented at international meetings, and the project has thus significantly added to the knowledge of the marine tephrochronology of the northeastern North Atlantic. These papers have already been repeatedly cited in the literature. The TeMa results have inspired a new project involving the investigation of diatom concentrations at Elphidium excavatum peaks associated with tephra peaks in the project core material. A list of the project's output 

Peer Reviewed Papers

Knudsen, K. L., Eiríksson, J., Bartels-Jónsdóttir, H. B. 2012: Oceanographic changes through the last millennium off North Iceland: Temperature and salinity reconstructions based on foraminifera and stable isotopes. Marine Micropaleontology 84-85 (2012) 54–73.

Gudmundsdóttir, E. R., Larsen, G. & Eiríksson, J. 2012: Tephra stratigraphy on the North Icelandic shelf: extending tephrochronology into marine sediments off North Iceland. Boreas, 10.1111/j.1502- 3885.2012.00258.x.

Guðmundsdóttir, E. R., Eiríksson, J. & Larsen, G. 2012: Holocene marine tephrochronology on the Iceland shelf: An overview. Jökull 62, 53-72.


Richard John Vilstrup Jarvis 2013. Palaeoceanographic and climatic changes during the late Weichselian and the Holocene off North Iceland: foraminifera and stable isotopes. Master Thesis (Specialeopgave) Department of Earth Science University of Aarhus, Denmark. 71 pp. 

Conference Presentations

Knudsen, K.L., Eiríksson, J., Gudmundsdóttir, E.R. & Larsen, G. 2014: Elphidium excavatum f. clavata – Related to oceanographic changes or tephra deposition on the North Icelandic Shelf. In Marchant, M. & Hromic, T. (eds.): International Symposium on Foraminifera FORAMS 2014, Chile, 19-24 January 2014. Grzybowski Foundation Special Publication 20, 88-89.

Gudmundsdóttir, E.R., Eiríksson, J. Knudsen K.L. and Larsen G. 2014. Impact of tephra deposition on benthic foraminifera: Evidence from the North Icelandic shelf. 31th Nordic Geological Winter Meeting. Lund, Sweden. 8-10 January 2014.

Esther Ruth Gudmundsdottir, Gudrun Larsen, Jon Eiriksson 2012: Highresolution marine tephrochronology on the North Icelandic shelf: a reference section for the northern North Atlantic region. AGU Fall Meeting, San Fransisco, USA, December 2012.

Esther Ruth Guðmundsdóttir, Jón Eiríksson, Guðrún Larsen 2012: Late glacial and Holocene tephra stratigraphy on the North Icelandic shelf. Erindi. Flutt á Nordic Geological Winter Meeting, Reykjavík, 9-12 January 2012.

Jesper Olsen, Karen Luise Knudsen, Jón Eiríksson, Paula Reimer 2012: Late-Glacial and early Holocene marine 14C reservoir ages off North Iceland (16-‐ 9 cal kyr BP) 06 -‐ Variations in radiocarbon reservoir effects. Erindi, flutt á 21st International Radiocarbon conference 2012 Paris, France.

Jesper Olsen, Karen Luise Knudsen, Jón Eiríksson, Paula Reimer Late Glacial marine 14C reservoir ages off North Iceland during the Younger Dryas period. Erindi á 30th Nordic Geological Winter Meeting [S3] Tephrochronology on land, in ice, lakes and sea.

Gudmundsdóttir, E.R., Larsen, G., Eiríksson, J.2011. Tephrochronology: a tool for dating the extremes. APEX Fifth International Conference and Workshop: Quaternary Glacial and Climate Extremes. Longyearbyen, Svalbard. June 1 -4, 2011.

Gudmundsdóttir, E.R., Larsen, G., Eiríksson, J. 2011. Tephrochronology as a tool for precise dating and correlation of Quaternary records. European General Assembly (EGU), Vienna, Austria, 03-08 April 2011

Guðmundsdóttir, E.R., Larsen, G., Eiríksson, J. 2011. Gjóskulagaskipan á norðanverðu landgrunni Íslands: Tenging við gjóskulög á landi. Geoscience Society of Iceland spring meeting, 15th Apríl 2011. 

Þetta vefsvæði byggir á Eplica