Deep sea hydrothermal vents

Question 1

Formation of vents

Answer 1

• form along mid ocean ridges - mountain ranges in the sea (1500-4000m deep)
• biggest = mid Atlantic ridge
• ridges are boundaries of tectonic plates which move around in the sea
• tectonic plates move shifting rocks (seafloor spreading) - where crack form
• cracks filled with water which are superheated by the magma and is under lots of pressure, where its forced out into plumes - the vents
• rich in nutrients and sulphides their known as black-smokers

Question 2

Ecology of the vents

Answer 2

• rich in minerals and sulphides
• found deep sea where little ground - vents are a large input, the whole ecosystem can be based on this source
• primary producers here are chemoautotrophic micro-organisms which oxidise the sulphides to make C compounds, forming basis of food chain
• animals will consume the bacteria directly, or will have symbiotic relationships with the bacteria
• characterised by low spud but high abundance

Question 3

Animals found include…

Answer 3

• scaly food gastropod
• yeti crab
• giant tube worm (polychaete)
• Pompeii worm
• swarming shrimp

Question 4

Scaly foot gastropod

Answer 4

Weird structure on foot made of iron sulphides, which its shell also contains (protects it from high temperatures possibly, but makes it very rough)

Question 5

Yeti crab

Answer 5

Hair on the crab thought to be filamentous bacteria protecting it from high temps

Question 6

Giant tube worms

Answer 6

Found in vents
•have plume used for collecting hydrogen sulphide
•3m long
•have incredibly rapid rates of growth
•have not gut but have tosses stuffed full of symbiotic bacteria which converts CO2 into C compounds by oxidising the sulphides

Question 7

Pompeii worm

Answer 7

• can tolerate very high temps
• feathery head which are gill-like structures that increase SA for gaseous exchange
• red as rich in Hb - not much O2, so can pick up low levels
• live in galleries (holes)
• can withstand up to 80°C (back end, not head)
• hair back - filamentous bacteria - protection from temp?
• feed on mud and deposits, possibly bacteria too

Question 8

The vent community

Answer 8

•over 500 new spp found there
•90% are endemic
•other 10 found in...
-other deep sea communities
-other chemosynthetic ecosystems 
•whale carcasses

Question 9

Whale carcass communities

Answer 9

Animals all feed on flesh
Zombie worms found on bone - living in tubes (polychaete)
•doesn’t have mouth or gut
•root system that digs into bone
•feeds on protein and fats of bone
•bacteria enable digestion
•F larger, Ms found in Fs tube
•M are precocial (larval)
•produce lots of eggs, like ‘dandelions’ in dispersal
•eggs carry on to find another carcass as their parent’s one will run out eventually