The vents are furiously spewing out an estimated 300 kg of water every second, and that water contains about 12 millimoles (mM) of hydrogen sulfide, the main food for the bacteria which feed the shrimp. We’ll say 12 mM is about 1.25 Calories (kcal; after great calculations by McCollom and Shock in 1997).
Our chocolate cake, which is ginormous, is probably at least 15000 kcal – so a little maths tells us that our vents are serving up about a slice of cake every second – and more than 2,000 delicious chocolate cakes each day. Plenty of food for bacteria – if only they can get to the fluids – which (unfortunately for them) are more than 400°C. It’s probably safer for them to stay in the diffuse areas, which have less hydrogen sulfide, but much more comfortable temperatures around 50°C. Funnily enough, this is where we find the majority of the shrimp – which carry the bacteria in their gills and other convenient parts of their bodies. Personally, I prefer chocolate cake to rotten-egg smelling hydrogen sulfide – but each to their own!
By Jeff Hawkes
|Jeff taking a sample from the CTD carousel to analyse methane – another great food source for bacteria|