Lecture 18 - Origins of vent species

Question 1

How to deal with sulfide - nonsymbiotic

Answer 1

Oxidize to thiosulfate

• coupled to energy production = ATP
• uncoupled - also usual

Question 2

How to deal with sulfide - Chemoautotrohic bacterial symbionts

Answer 2

Sulfur oxidizing to sulfate

• bacteria oxidize to sulfate and protect animal
• host provides sulfur compound to symbionts

Question 3

How to transport sulfide

Answer 3

Sulfide binding - used by tubeworms, clams
Host oxidation to thiosulfate
Symbiont oxidation to sulfate

Question 4

How do the acquisition of symbiotic bacteria change vestimentiferans?

Answer 4

No longer need mouth or gut
Bacteria is housed in trophosome, which turns brown due to the sulfur
Gills are also highly vascularized and house lots of bacteria

Question 5

What happens when O2 and sulfide is bound to hemoglobin?

Answer 5

They stop spontaneously reacting with each other

Question 6

What temp shows the max metabolic rate for Riftia?

Answer 6

25*C

max consumption of CO2, H2S, and O2

Question 7

What does a small Riftia plume tell you?

Answer 7

Low metabolic rate

Slow flux of sulfide from roots = low O2 need (from plume) = low growth over time

Question 8

Clam -sites of carbon fixation and sulfide uptake

Answer 8

carbon fixation - gills

sulfide uptake - foot

Question 9

Riftia - sites of carbon uptake, O2 uptake, sulfide uptake, nitrogen fixation, sulfide oxidation

Answer 9

plume - carbon, sulfide, O2 uptake

trophosome - sulfide oxidation, nitrogen fixation to amonia

Question 10

mussels - sites of uptake and oxidation

Answer 10

all in gills

all symbionts in gills too

Question 11

Why are cnidarians ill-equipped for chemoautotropic endosymbioses?

Answer 11

Lack the complex structure for high O2 uptake and circulation of materials

Instead, they have large areas to absorb light for photoautotrophic