Thomas Dahlgren

Assistant professor, Systematics and Biodiversity

Tel: 46 (0)31 786 36 62
Cellphone: 46 (0)70 3662042
thomas.dahlgren@zool.gu.se

Research interest

ANTARCTIC CHEMOSYNTHETIC ECOSYSTEM STUDY (ACES)

PI's: Thomas Dahlgren, Göteborg University; Craig Smith, University of Hawaii; Adrian Glover, Natural History Museum.

Scientist onboard Oden 2007/2008: Dr Kirsty Kemp

As recently as 1977, the discovery of hydrothermal vent ecosystems has shown that deep, remote and ephemeral habitats are a source of remarkable evolutionary novelty, ecological interactions and possibly the origin of life itself. An example of this is the unusual communities of animals that develop on the remains of dead whales, or 'whale-falls'. Whales are the giants of the ocean, and can reach over 100 tonnes body weight. On death, the majority of whales sink to the seafloor, and represent an enormous energy source in an otherwise food-poor environment, where sunlight and photosynthesis is usually absent. Our project focus on what happens to the bones left behind, which may remain on the seabed for up to 100 years. While investigating experimentally sunk whale carcasses in the North Sea we have recently discovered a remarkable new species of animal called Osedax mucofloris, latin for 'bone-eating mucus flower'. This worm, closely related to the giant tubeworms found on hydrothermal vents, has no mouth or gut. Instead, it has adapted to live on whale bones by growing a system of root-like tubes into the bones of large dead whales, and using bacteria housed inside these roots to obtain energy from the oil-rich bone marrow. This is the first time that this type of symbiotic relationship has been found in the animal kingdom. In our project, in which the Oden NSF cruises are an important part, we will investigate whale-falls, whale-bones and associated fauna including Osedax worms at shelf sites in the Southern Ocean for the first time. We will use the latest technology, including landers to answer a range of questions regarding the role of whale-falls in Antarctic ecosystems. We anticipate finding species new to science in Antarctica, one of the worlds most extreme environments. Furthermore, we will use a molecular genetic approach to understand the potential impacts that historical whaling has had on whale-fall organisms.

Publications

PUBLICATIONS IN PEER-REVIEWED JOURNALS

2009 Glover, AG, Sundberg, P, Dahlgren TG. In Linnaeus’ Wake: 300 years of marine discovery. Zoologica Scripta. 38 (suppl. 1), 1-6.

2009 Wiklund H, Glover AG, Johannessen P, Dahlgren TG. Cryptic speciation at organic-rich marine habitats: a new bacteriovore annelid from whale-fall and fish farms in the North East Atlantic. Zoological Journal of the Linnean Society 155, 774-785.

2009 Pleijel F, Dahlgren TG, Rouse GW. Progress in science: from Siboglinidae to Pogonophora and Vestimentifera and back to Siboglinidae. Comptes rendus de l'Académie des sciences. 332 (2-3), 140-148.

2009 Thornhill DJ, Dahlgren TG, Halanych KM. The evolution and ecology of Ophryotrocha (Dorvilleidae, Eunicida). Chapter 13. In Annelids in Modern Biology. Shain, D., Editor.

2008 Glover AG, Kemp KM, Smith CR, Dahlgren TG. On the role of bone-eating worms in the degradation of marine vertebrate remains. Proceedings of the Royal Society B 295, 1959-1961.

2008 Stet RJM, Mudde K, Wynne JW, Nooijen A, Dahlgren TG, Ruzzante, DE, André C. Characterization of a major histocompatibility class II A gene (Clha-DAA) with an embedded microsatellite marker in Atlantic herring, Clupea harengus. Journal of Fish Biology. 72, 1-16.

2006 Dahlgren TG, Wiklund H, Källström B, Lundälv T, Smith CR, Glover AG. A shallow-water whale-fall experiment in the north Atlantic. Les Cahiers de Biologie Marine 47(4): 385-389.

2006 Ryman N, Palm S, André C, Carvalho GR, Dahlgren TG, Jorde PE, Laikre L, Larsson LC, Palmé A, Ruzzante DE. Power for detecting genetic divergence: differences between statistical methods and marker loci. Molecular Ecology 15, 2031-2046.

2006 Ruzzante DE, Mariani S, Bekkevold D, Andre C, Mosegaard H, Clausen LAW, Dahlgren TG, Hutchinson WF, Hatfield EMC, Torstensen E, Brigham J, Simmonds EJ, Laikre L, Larsson LC, Stet RJM, Ryman N, Carvalho GR. Biocomplexity in a highly migratory pelagic marine fish, Atlantic herring. Proceedings of the Royal Society B (published online 21/2/2006)

2005 Glover AG, Källström B, Smith CR, Dahlgren TG. World-wide whale worms? A new species of Osedax from the shallow north Atlantic. Proceedings of the Royal Society B 272, 2587–2592.

2005 Glover AG, Goetze E, Dahlgren TG, Smith CR. Morphology, reproductive biology and population genetics of the whale-fall and hydrothermal vent specialist, Bathykurila guaymasensis Pettibone, 1989 (Annelida: Polynoidae). Marine Ecology 26, 223-234.

2005 Bekkevold D, André C, Dahlgren TG, Clausen LAW, Torstensen E, Mosegaard H, Carvalho GR, Christensen TB, Norlinder E, Ruzzante DE. Environmental correlates of population differentiation in Atlantic herring. Evolution 59(12), 2656–2668.

2005 Mariani S, Hutchinson WF, Hatfield EMC, Ruzzante DE, Simmonds JE, Dahlgren TG, Andre C, Brigham J, Torstensen E, Carvalho GR. North Sea herring population structure as revealed by microsatellite analysis. Marine Ecology Progress Series 303, 245–257.

2004 Dahlgren TG, Glover A, Baco A, Smith CR. Fauna of whale falls: systematics and ecology of a new polychaete (Annelida: Chrysopetalidae) from the deep Pacific Ocean. Deep Sea Research II 51(12), 1873-1887.

2003 Schander C, Halanych KM, Dahlgren TG, Sundberg P. Test of the monophyly of Odostomiinae and Turbonilliinae (Gastropoda, Heterobranchia, Pyramidellidae) based on 16SmtDNA sequences. Zoologica Scripta. 32, 243-254.

2003 Weinberg JR, Dahlgren TG, Trowbridge N, Halanych KM. Genetic differences within and between species of Deep-Sea Crabs (Chaceon) from the north Atlantic Ocean. The Biological Bulletin. 204, 318-326.

2002 Halanych KM, Dahlgren TG, McHugh D. Unsegmented annelids? Possible origins of four lophotrochozoan worm taxa. Integrated and Comparative Biology 42, 678-684.

2002 Weinberg JR, Dahlgren TG, Halanych KM. Influence of rising sea temperature on commercial bivalve species of the U.S. Atlantic coast. Pages 131-140 in N. A. McGinn, editor. Fisheries in a changing climate. American Fisheries Society, Symposium 32, Bethesda, Maryland.

2002 Tzetlin AB, Dahlgren TG, Purschke G. Ultrastructure of the body wall, body cavity, nephridia and spermatozoa in four species of the Chrysopetalidae (Annelida). Zoologischer Anzeiger 241, 37-55.

2001 Dahlgren TG, Åkesson B, Schander C, Halanych KM, Sundberg P. Molecular phylogeny of the model annelid Ophryotrocha. Biological Bulletin of the Marine Biological Laboratory, Woods Hole 201, 193-203.

2000 Dahlgren TG, Weinberg JR, Halanych KM. Phylogeography of the ocean quahog (Arctica islandica): influences of paleoclimate on genetic diversity and species range. Marine Biology 137, 487-495.

2000 Dahlgren TG, From individuals to deep metazoan branches: relationships and delineation of recent and fossil Chrysopetalidae (Annelida). 29 pp., PhD Thesis, Göteborg University.

2000 Dahlgren TG, Lundberg J, Pleijel F, Sundberg P. Morphological and molecular evidence of the phylogeny of Nereidiform polychaetes (Annelida). Journal of Zoological Systematics and Evolutionary Research 38(4), 249-254.

1998 Pleijel F, Dahlgren TG. Phylogeny of Phyllodocida and Nereidiformia (Polychaeta, Annelida). Cladistics 14, 129-150.

1996 Dahlgren, TG Two new species of Dysponetus (Polychaeta: Chrysopetalidae) from Italy and Papua New Guinea. Proceedings of the Biological Society of Washington 109, 575-585.

1995 Dahlgren TG, Pleijel P. On the generic allocation of Chrysopetalum caecum (Polychaeta: Chrysopetalidae). Mitteilungen aus dem Hamburgischen zoologischen Museum und Institut 92,159-173.

POPULAR SCIENCE PUBLICATIONS

2006 Dahlgren TG, Wiklund H. Hur vi streckkodade Moby Dick. Fauna och Flora 2006 (2), 8-9.

2005 Dahlgren TG, Källström B, Lundälv T. Nyupptäckt biotop drivs av olja. Havsmiljön Juni 2005.

2005 Källström B, Dahlgren TG, Lundälv T. Länge leve den döda valen! –unik biodiversitet på sjunkna valkadaver. Fauna och Flora 2005 (1), 36-40.

1992 Dahlgren, TG. Sharkfishing in Orissa. Bay of Bengal News. Quarterly publication of the Bay of Bengal Programme. FAO, Rome. 46: 15-21.

CONFERENCE PRESENTATIONS (RECENT)

Mariani S, Hatfield EMC, Hutchinson WF, Simmonds EJ, Bekkevold D, Ruzzante DE, André C, Brigham J, Dahlgren TG, Clausen LAW, Torstensen E, Carvalho GR. 2004. “Admixture analysis of herring feeding aggregations in the northern North Sea¿, ICES Annual Science Conference, Vigo - Spain, 22-25/09/2004.

André, C. and (alphabetically) Bekkevold D, Brigham J, Carvalho, GR, Clausen LAW, Dahlgren TG, Hatfield EMC, Hutchinson WF, Laikre L, Larssen L, Mariani S, Mosegaard H, Mudde K, Ruzzante DE, Ryman N, Simmonds EJ, Stet R, Torstensen E. 2005. “Comparison of four different genetic markers for stock identification in Atlantic herring¿, ICES Annual Science Conference, Aberdeen, Scotland, 18-24/09/2005.

Bekkevold D, Mariani S, André C, Clausen LAW, Dahlgren TG, Hutchinson WF, Torstensen E, Hatfield EMC, Simmonds EJ, Mosegaard H, Brigham J, Carvalho GR, Ruzzante DE. 2005. “Using genetic markers to determine Atlantic herring population structure in the North Sea–Baltic transition zone and to monitor mixed stock fisheries in the Skagerrak¿, ICES Annual Science Conference, Aberdeen, Scotland, 18-24/09/2005.

Mariani S, Hutchinson WF, Hatfield EMC, Ruzzante DE, Simmonds EJ, Dahlgren TG, André C, Brigham J, Torstensen E, Carvalho GR. 2005. “Microsatellite analysis of North Sea herring spawning aggregations¿, ICES Annual Science Conference, Aberdeen, Scotland, 18-24/09/2005.

Dahlgren TG, Wiklund H, Källström B, and Glover AG. Atlantic whale-falls: Prospects and insights from carcasses sunk at shelf depth. Third International Symposium on Hydrothermal Vent and Seep Biology 12-16/09/2005

Glover AG, Källström B., Smith CR, and Dahlgren TG. World-wide whale worms? A new pogonophoran annelid from a whale-fall in the north Atlantic. Third International Symposium on Hydrothermal Vent and Seep Biology 12-16/09/2005