Deep Sea Hydrothermal Vents

Question 1

Where do hydrothermal vents form?

Answer 1

• Along mid ocean ridges
• Ridges at the boundaries of tectonic plates

Question 2

How are hydrothermal vents formed?

Answer 2

• Cracks form in sea floor due to movement of plates
• Magma moves around
• Water flows into the crack formed - is heated by magma
• Water under lots of pressure is forced out and forms thermal vents

Question 3

Why are hydrothermal vents so productive?

Answer 3

• Full of minerals from the earth’s crust (sulphides)
• Micro-organisms feeds off the sulphides (chemoautotrophic micro-organism)
• Bacteria is either consumed directly by animals in the deep sea or form symbiotic relationships
• Low numbers of species but high densities
• Typical of very productive environments (like salt marshes and estuaries)

Question 4

Examples found on hydrothermal vents

Answer 4

• Scaly foot snail: scales on foot made of sulphides (protection?)
• Yeti crab: Hairy arms are filamentous bacteria that grow on the arms

Question 5

Hydrothermal vents: Giant tube worm

Answer 5

• No gut but symbiotic relationship with bacteria
• Bacteria live in tissues of the worm
• Collect hydrogen sulphides (usually toxic to animals) from vents and the bacteria live on the H2S
• Have haemoglobin
• Rapid growth rate for invert (3m long)

Question 6

Hydrothermal Vents: Pompeii worm (polychaete)

Answer 6

• Haemoglobin
• Covered in filamentous bacteria (looks like hair)
• Can tolerate high temps (80°c)
• Deposit feeder
• Dorsal surface colonised by bacteria
• Bacteria possible protection from high temperatures
• Gallery dweller - lives on vent chimney in gaps

Question 7

Hydrothermal vents: Swarming shrimp

Answer 7

• Heterotrophs
• Filamentous bacteria found in branchial chamber
• May farm bacteria for food
• No compound eye
• Have a dorsal organ very sensitive to light

Question 8

Where do the organims that live on hydrothermal vents come from?

Answer 8

• Over 500 new species discovered in hydrothermal vents
• Over 90% only found in vents
• Some overlap with deep sea ecosystem
• Large mammal carcases - input of nutrients
• Chemosynthetic ecosystems

Question 9

What happens to a whale carcass in the deep sea?

Answer 9

• Polychaete worms (zombie worms)
• Males precotial: Larval stage but are able to produce sperm
• Root system penetrates bones and extracts fats and proteins