East Pacific Rise. Hydrothermal vent ecology - Larval supply, colonization, and community development. Biogeography of hydrothermal vent fauna

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1 149 sites visually confirmed as active hydrothermal vents Hydrothermal vent ecology - Larval supply, colonization, and community development Presented by: Stace Beaulieu InterRidge Coordinator and Research Specialist in Biology Woods Hole Oceanographic Institution Qingdao Ocean Sciences Summer School 17 July 2008 Biogeography of hydrothermal vent fauna S. Beaulieu, Alvin Dive 4261 Van Dover, C.L. et al. (2002) Science 295: East Pacific Rise 1

2 Ridgea piscesae (siboglinid) Northeast Pacific Alviniconcha hessleri (hairy gastropod) Western Pacific Shrimp Central Indian Ridge Mid-Atlantic Ridge Gastropods Mussels Shrimp (Rimicaris exoculata) Anemones Slide courtesy T. Shank 2

3 Why are there biogeographic provinces for hydrothermal vent fauna? Van Dover et al Generally considered due to: - historical (plate tectonics) processes, and - contemporary dispersal barriers. WHOI Oceanus magazine Slide courtesy Meg Tivey Biogeography of hydrothermal vent fauna: Most recent research ChEss (Chemosynthetic Ecosystems) project of the Census of Marine Life program Bachraty, C. et al., posted 21 April 2008 on Nature Precedings 3

4 InterRidge Working Group for Vent Ecology Chairs - Charles Fisher (Penn State Univ., USA) and Stephane Hourdez (Roscoff, France) Group Member from China Xiang Xiao, Third Institute of Oceanography Hydrothermal vent ecology Major questions Objectives: - foster cutting edge studies of the ecology of hydrothermal vents, - facilitate international collaborations and sharing of samples. Current composition of the community at a given vent site is the result of: - evolutionary history of the taxa, - present-day interactions among species, - physiological adaptations of each of the species. - How far do larvae of vent-endemic fauna disperse? How do we quantify larval dispersal and supply to hydrothermal vents? - How quickly are new vent sites colonized? How do we study larval settlement and colonization at hydrothermal vents? - How do communities change over the life time of a vent? How do we analyze seafloor imagery for time-series observations of community development? Focus on East Pacific Rise Alvinellid polychaetes Tubeworm Riftia pachyptila Population genetics S. Beaulieu, Alvin Dive 4261 Drawing by WHOI Graphics 4

5 Larval dispersal and settlement are necessary to establish and maintain benthic communities? 290μm Nectochaete 170μm Lepetodrilus sp. How do we quantify larval dispersal and supply to hydrothermal vents? Plankton pump moored at hydrothermal vent Plankton pumps (restricted use on cruise): Measure concentration of larvae; used with current meters for advective flux (dispersal), if assume passive particle trajectories Sediment traps (longer deployment): Measure time series of sinking flux, likely a better measure of larval supply (larvae competent to settle) (2005) Larvae more abundant near-bottom and on-axis Temporal patterns in abundance differed among species Nov cruise Beaulieu et al. (2008, submitted) Nov cruise May 2000 cruise 5

6 Sediment traps and current meters moored at two locations, ~1.5 km apart Data for 10 days at Choo Choo site Transport along axis (m) How far do larvae of vent-endemic fauna disperse? (2001) Larval lifespan at least 38 days Potential along-ridge dispersal distances <100km Flux of larvae into the sediment trap Episodic flow reversals Loss due to across-ridge flow Adams and Mullineaux (2008, in press) How do we study larval settlement and colonization at vents? Hydrothermal vent ecology Major questions - Direct observation (as soon as possible after volcanic or seismic event) - Manipulative experiments - How far do larvae of vent-endemic fauna disperse? How do we quantify larval dispersal and supply to hydrothermal vents? - How quickly are new vent sites colonized? How do we study larval settlement and colonization at hydrothermal vents? - How do communities change over the life time of the vent? How do we analyze seafloor imagery for time-series observations of community development? Launching Alvin from R/V Atlantis 6

7 Basalt settlement panels deployed next to chemical sensor Experiment site 1 Recovering basalt settlement panels A. Nevala (WHOI) 9 months at Expt site 1 (colonized by tubeworms including Tevnia jerichonana, Riftia pachyptila, and Paralvinella grasslei) 4 days at Expt site 1 Sievert et al., (2006); Beaulieu, unpub. data Results: macrofauna sorted from basalt settlement panels 140 Macrofauna colonizing basalt panels Longer-term experiment: Basalt blocks deployed in different habitat zones No. individuals / panel Sessile Motile n=2 n=2 Alvinellids at vent Chimney 20 0 nd nd E1 E2 C E1 E2 C E1 E2 C E1 E2 C E1 E2 C 4-d 9-d 13-d 2-mo 9-mo Beaulieu, unpub. data Settlers vs. immigrants Tubeworm Bivalve Suspension feeder Periphery Slide courtesy L. Mullineaux 7

8 (2003) Inter-specific interactions during colonization Blocks (3 replicates per time period) deployed for 5-37 months within different habitat zones Negative (Inhibition) Positive (Facilitation) Mullineaux et al., (2003) How quickly are new vent sites colonized? Short answer: As quickly as we have started to look Larval settlers within a few months (possibly weeks based on settlement panel experiments), likely dependent on distance to larval sources Hydrothermal vent ecology Major questions Tubeworm Tevnia jerichonana at EPR < 1 year after 2005/2006 eruption - How far do larvae of vent-endemic fauna disperse? How do we quantify larval dispersal and supply to hydrothermal vents? - How quickly are new vent sites colonized? How do we study larval settlement and colonization at hydrothermal vents? - How do communities change over the life time of the vent? How do we analyze seafloor imagery for time-series observations of community development? Nov LADDER I cruise 8

9 Development of benthic communities at 9º N EPR succession Patterns of community development based on repeated visits to 9º N EPR Images at Biomarker and senescence Similar to patterns reported for communities at Galapagos Rift [Hessler et al. (1988) DSR 35: ] Shank et al. (1998) Recent eruption: 2005/2006 Classic paper: Corliss et al. (1979) Science Submarine thermal springs on the Galapagos Rift Rose Garden at Galapagos Rift in 1979 Garden of Eden Re-discovered Dive 4120 May 2005 Visited in 1979, 1985, 1988, and

10 Return to the Galapagos Rift Cruise in 2002: Using Autonomous Benthic Explorer (ABE) ABE Survey Lines at Galapagos Rift in 2002 Discovery of Rosebud at Galapagos Rift in 2002 Community age estimated <2.5 years Shank et al. (2003) What did we find in 2005? 10

11 Rosebud Marker B Transect mosaic 2002 Panorama mosaic How do communities change over the life time of the vent? Life time of vents in the eastern equatorial Pacific: EPR: 15 yrs ( /6) Galapagos Rift: ~25 yrs (Rose Garden <1977 ~2000, Garden of Eden ~ >2005) Communities appear to develop via successional sequence of megafauna: Hydrothermal vent ecology Major questions - How far do larvae of vent-endemic fauna disperse? - How quickly are new vent sites colonized? - How do communities change over the life time of the vent? Tevnia at EPR ** Important to deploy markers and/or have very good navigation to return to same sites for time-series observations Even at one of the best-studied sites in the world-- 9º N EPR-- we still have so many questions to answer! 11

12 General reference: The Ecology of Deep-Sea Hydrothermal Vents Cindy Lee Van Dover (2000) Handbook of Deep-Sea Hydrothermal Vent Fauna Editors: D. Desbruyeres, M. Segonzac & M. Bright 2 nd edition (2006) For more information: InterRidge ( ChEss ( Acknowledgments Jian Lin and Chris German (InterRidge Chair and Co-Chair) Lauren Mullineaux, Tim Shank, Stefan Sievert, and Adam Soule (WHOI) Yuri Rzhanov (University of New Hampshire) Funding from WHOI s Deep Ocean Exploration Institute and the National Science Foundation (USA) 12