Friday 28 Feb, 4.30pm, Neil Chalmers Seminar Room
Livestreamed on http://www.youtube.com/user/SciFriSeminars
Chemosynthesis-based communities through time: a 3.2 billion year history
Cris Little, University of Leeds
At the beginning of this seminar I will briefly review the ecology of modern chemosynthetic communities at hydrothermal vents, hydrocarbon (‘cold’) seeps and sunken dead whales (whale-falls) touching on biogeography and discussing evolutionary issues, including molecular divergence estimates for several major taxonomic groups.
Then I will turn to the fossil record of these communities, which for vents goes back 3.25 billion years. I will show that vent and seep fossil assemblages have changed in taxonomic structure during the Phanerozoic, from brachiopod dominated communities in the Palaeozoic and early Mesozoic to mollusc (bivalve and gastropod) dominated communities from the later Mesozoic onwards. Some of the ecologically dominant taxa that have chemosymbiotic bacteria (e.g. vesicomyid clams and bathymodiolin mussels) are relative newcomers to vent and seep environments and were preceded by other, now extinct, bivalves that may (or may not) also have had symbionts.
Whale-fall communities from the Miocene are similar in structure to modern examples in the so-called sulfophilic stage, but older Oligocene and latest Eocene whale-fall communities lack some of the typical molluscs. This may be related to the small size of whales in their early evolutionary history. Prior to the Eocene whale-fall-like communities may have existed on sunken marine reptiles (e.g. turtles, ichthyosaurs and plesiosaurs), or even large fish carcasses.
SciFri is a cross-departmental science seminar series and social event run by the NHM Science Forum, held the last Friday of each month. The 45 minute talks are intended to be informal, contemporary, inter-disciplinary and cover a range of fields including the latest research, curation, science policy, publishing, media, fieldwork and science methods. If you have ideas for future speakers from any of these areas please contact the seminar organiser Adrian Glover, Life Sciences Department.