Monterey Bay Aquarium Research Institute

Robert C. Vrijenhoek
Senior Scientist

Monterey Bay Aquarium Research Institute
7700 Sandholdt Road
Moss Landing, CA 95039
Phone: (831) 775-1799
Fax: (831) 775-1620

  • Interests
  • Genetics and Evolution, Marine Biology, Conservation

  • Research
  • Studies focus on the ecological and evolutionary consequences of genetic diversity in animals and associated microbes.

    • Bone-Eating worms
    • Osedax worms were discovered during February 2002 living on the bones of a whale found at 2891 m depth in Monterey Bay. Osedax females grow complex roots that contain symbiotic bacteria and invade the bone on which these mouthless and gutless worms subsist. Osedax males are microscopic, and they live inside the gelatinous tubes produced by the females. Sex ratios are highly skewed with more than 25 males living in an average female's tube. MBARI press release

      Vrijenhoek RC, Johnson SB, Rouse GW (2009) A remarkable diversity of bone-eating worms (Osedax; Siboglinidae; Annelida). BMC Biology 7, 74 (13 pages).  URL

      Vrijenhoek, RC, Johnson, S, Rouse, GW, 2008. Bone-eating Osedax females and their "harems" of dwarf males are recruited from a common larval pool. Molecular Ecology 17, 4535-4544. URL

      Rouse GW, Goffredi SK, Vrijenhoek RC (2004) Osedax: Bone-Eating Marine Worms with Dwarf Males. Science 305: 668-671. URL

    • Gene flow and dispersal
    • Since 1989, research has focused on gene flow and evolutionary relationships of organisms endemic to deep-sea hydrothermal vents and cold water seeps. Most vent-endemic invertebrates have effective modes of dispersal that maintain genetic continuity among populations distributed thousands of kilometers along mid-ocean ridge systems. For some organisms, however, structural aspects of the ridge system (large transform faults and other discontinuities such as the Easter Microplate) result in restricted gene flow or isolation among populations.

      Coykendall DK, Johnson SB, Karl SA, Lutz RA, Vrijenhoek RC (2011) Genetic diversity and demographic instability in Riftia pachyptila tubeworms from eastern Pacific hydrothermal vents. BMC Evolutionary Biology 11:  96. URL

      Audzijonyte A, Vrijenhoek R (2010) When gaps really are gaps: statistical phylogeography of hydrothermal vent invertebrates. Evolution 64, 2369-2384. URL

      Vrijenhoek RC (2010) Genetic diversity and connectivity of deep-sea hydrothermal vent metapopulations. Molecular Ecology 19, 4391-4411. URL

    • Molecular Systematics
    • Research has focused on the the evolutionary histories of vent and seep invertebrates. Phylogenies have been generated for many of the dominant vent taxa including clams, mussels, shrimp, and tubeworms. Present evidence suggests that taxa have had relatively recent origins during the last 100 million years.

      Johnson SB, Warén A, Lee R, et al. (2010) Rubyspira, new genus and two new species of bone-eating deep-sea snails with ancient habits. Biological Bulletin 219, 166-177.

      Vrijenhoek RC (2009) Cryptic species, phenotypic plasticity, and complex life histories: Assessing deep-sea faunal diversity with molecular markers. Deep Sea Research Part II: Topical Studies in Oceanography 56, 1713-1723.

      Little CTS, Vrijenhoek RC (2003) Are hydrothermal vent animals living fossils? Trends in Ecology and Evolution 18: 582-588

    • Marine Symbiosis
Vertical transmission of symbiotic bacteria ensures widely dispersing hosts with suitable bacteria when colonizing chemosynthetic habitats. Deep-sea vesicomyid clams transmit their symbionts through eggs; consequently, variation in the symbiont genome is genetically coupled with variation in the host's cytoplasmically transmitted mitochondrial genome. Cytoplasmic co-transmission results in a phylogenetic pattern of co-speciation be-tween the clam host and symbiont genomes. In contrast, vestimentiferan tubeworms (fam. Siboglinidae) acquire their sulfide-oxidizing endosymbionts from the local environment, and they show no evidence for co-speciation. These transmission modes have significant demographic consequences for microbial population structure and evolution.

Vrijenhoek RC (2010) Genetics and evolution of deep-sea chemosynthetic bacteria and their invertebrate hosts. In: The Vent and Seep Biota, Topics in Geobiology 33 (ed. Kiel S), pp. 15-50. Springer, Berlin. Preprint

Won Y-J, Jones WJ, Vrijenhoek RC (2008) Absence of co-speciation between deep-sea mytilids and their thiotrophic endosymbionts. Journal of Shellfish Research 27, 129-138.

Goffredi SK, Johnson SB, Vrijenhoek RC (2007) Genetic and potential function of microbial symbionts associated with newly discovered species of Osedax polychaete worms. Applied and Environmental Microbiology 73, 2314-2323.

  • Asexual reproduction