Lecture 16 - Hydrothermal Vents

Question 1

Slow spreading midocean ridges

Answer 1

20 - 40 mm/year

Mid-Atlantic Ridge
Gordo Ridge

Question 2

Intermediate spreading midocean ridges

Answer 2

50 - 60 mm/year

Galapagos Rift
Northern East Pacific Rise
Juan de Fuca Ridge
N Gorda Ridge
East Lau Spreading Center

Question 3

Fast Spreading midocean ridges

Answer 3

110 mm/year

East Pacific Rise
EPR

Question 4

Superfast spreading midocean ridge

Answer 4

> 150 mm/year

S East Pacific Rise

Question 5

Black smoker vent properties

Answer 5

up to 400*C
No O2
High Sulfide
Metals - high Fe++, Mn++, Cu
High methane (CH4)
High HS

Question 6

Ambient bottom water around vents

Answer 6

2*C
110uM O2
No sulfide

Question 7

Animals at vents live in temps up to what?

Answer 7

40*C

Question 8

How does the pH of vents affect stability of carbon in environment?

Answer 8

CH4 equilibrium shifts to CO2, making carbon more readily available

Question 9

Giant tube worm scientific name

Answer 9

Vestimentiferans - Riftia

Question 10

East Pacific Rise Succession

Answer 10

1. Bacterial snow - (in)organic material
2. Tevnia dominates after 1 yr (small tube)
3. Riftia dominates after 2 years
4. Mussels dominate 10-15 yrs

Question 11

Reasons for succession of Riftia by mussels

Answer 11

1. Competition b/t mussels and Riftia for space and flow
2. Mussels consume Riftia larvae
3. Change in water chemistry favoring mussels
   
   • mussels can feed at low vent flows

Question 12

What vent has no mussles?

Answer 12

21 N on East Pacific Rise (tip of Baja)

Question 13

What do clams take up from the sediment at vents?

Answer 13

Sulfide

Question 14

What does the position of Riftia tubes tell you about the vents?

Answer 14

Straight up = young vent with high flow

Turned/lowered to ground/openings = older, low flow