1. Symbiosis and the Deep Sea
Summer Workshop in Marine Science
Georgia Institute of Technology
Colleen M. Cavanaugh
Organismic and Evolutionary Biology
Harvard University

2. My 7th grade teacher, Mr. Frew and Rotifers
My 7th grade teacher, Mr. Frew and Rotifers St Marys of Redford, Detroit, Michigan

3. Symbiosis Gr. from syn with + bioun to live
Close prolonged association
of benefit to one or more partners
Globally important phenomenon –
-powerful effects on
physiology, ecology, evolution,
of all living organisms
Vary with respect to
- degree of dependence
- obligate vs. facultative
- intimacy (epi – endosymbionts)

4. Symbiosis – ecological and evolutionary potential
Symbiosis – ecological and evolutionary potential
Peanuts (legumes)
Corals
Corals
Access energy/nutrients
aphid
Buchnera
mitochondria
Rhizobium
Nutrition
Colonize new environments
soybeans
Protection
Camouflage
chloroplasts

5. Lichens: Fungi + Photosynthetic microbes
Cladonia rangiferina
Lobaria pulmonaria
Green algae
Fungi

6. 100 times more microbial genes than human genes…
The Human Microbiome
1014 microbial cells in the gut, human cells in the body…

7. The deep sea Ocean covers 71% of the Earth's surface
Contains 97% of the planet's water
Deep sea = depths greater than 1000 fathoms (~1800 m)
~ 95% of living space on earth
below 1,000 meters
8 tons per square inch at deepest point
equal to one person supporting 50 jumbo jets!
90% of all volcanic activity in the ocean
Yet more than 95 percent of the underwater world remains unexplored. 
The deep sea
You should discuss the hydrothermal vent ecosystem
Located along speading centers, back arc basins,etc
A giant coffee percolator;
Temp ranges up to 350 C; down to near freezing
Chemicals include hydrogen sulfde (more poisonous than cyanide); highly variable pH (2-8); pressures typically between 4000 and 6000 psi
(balance a car on a broomstick on your hand)
Deep sea vents discovered in 1977

8. Deep sea hydrothermal vents

9. Earth – Seafloor spreading centers

10. Seafloor spreading centers - volcanoes

11. Deep-sea hydrothermal vents
Discovered in 1977
Biological phenomena
Revolutionized perceptions of
Deep sea
Primary production
Chemosynthesis
Symbioses

12. Alvin
DSV Alvin

13. The deep sea and Mars
Citation

14. Warm vents Black smokers
Citation

15. Deep-sea hydrothermal vent Chemistry Depth ~2500 m Pressure 2500 Atm
deep vent
SW fluid___
Temp >350C pH
[H2S] ~330 mM mM
[DIC] mM
CO mM >1 mM

16. Photosynthesis / Chemosynthesis
Light + H2O +CO2
--> Sugar [CH2O] + O2

17. Deep sea hydrothermal vent tubeworms
Citation

18. Deep sea vents – Riftia pachyptila

19. Riftia pachyptila symbiosis Chemosynthesis Energy - S oxidation
CO2 fixation
N assimilation
Nutrients – macro/micro

20. Chemosynthetic symbioses
Benefits to partners
Host
Nutrition using non-metazoan
carbon and energy sources
Symbiont
Access to substrates from
reducing and oxidizing
environments

21. Hydrothermal vent symbioses – host diversity

22. Earth – Life above, in, and below the ocean
Citation

23. Symbioses and sediments
Tidal mudflat
Citation

24. Coastal sediment symbioses
Y-tube: Cavanaugh Lab UTube Link

25. Atlantic coast bivalve,
Solemya velum
Y-tube: Cavanaugh Lab UTube Link

26. Sapelo Island, Georgia