The Deep Sea Diet: Not all it’s gassed up to be
Down in the deep
At the bottom of our oceans in a habitat almost completely unknown to us, there lives a group of organism’s that unlike almost every other on the plant don’t rely on the sun for their food. Instead they rely on hydrogen sulphide that is spewed from hydrothermal vents on the ocean floor at almost 400°C. Now you may recognise hydrogen sulphide as the ‘rotten egg chemical’ this is due to the smell the compound creates and is quite often associated with volcanic areas.
These ‘hotspots’ created by the hydrothermal vents are relative oases in what is otherwise a very harsh environment attracting settlers of all shapes and sizes from Tube Worms to Spider Crabs (Shown Below). These organisms depend on the heat and nutrition pumped from these vents just to survive and if the vent were to close then all of the sedentary organisms would soon perish if another did not open soon enough.
How do they find them?
The first settlers are bacteria which are then usually followed by the larvae of the tube worm which are typically among the first to settle, being free swimming, although they are carried by the current they can direct themselves towards towards environments that they find more positive. They probably use temperature and salinity as references of where to settle as they begin their metamorphosis into adulthood. Then once you have your first settlers which will probably include annelids and gastropods such as the ‘scaly foot gastropod‘ then you begin to attract mobile predators.
This continues with an influx of fish and crustaceans who in turn also carry parasitic larvae of more settlers from other hydrothermal vents that these organisms have visited previously and soon enough you have a self sustaining ecosystem.
How life survives:
The first settler species such as the Tube Worm can convert hydrogen sulphide into energy much in the same way plants use photosynthesis to convert light into energy. But instead of the product being oxygen the product is sulphur. The point being that these organisms then grow as a result of the energy taken from the hydrothermal vents and then they themselves become the food source for every other organism that would then settle at the vents. This food chain extends upwards all the way to sharks with the Six gilled shark being a well known predator that can be found hunting near hydrothermal vents.
The fact that life has found a way to survive at such a desolate place on planet earth and such an extreme environment relative to any place should fill us with huge amounts of hope as to what else we could find not only on our world but on other planets as humans explore more and more of what surrounds us. If life can survive with no light and not just survive but flourish then thinking that life could be present within our own solar system suddenly becomes not that far fetched. As well as this it also goes to show what else we could find over the next few years on our own oceans of which we know even less about than the aforementioned space.