Sea Floor Venting

6 May 2020

Robert sent in this one and it is a cracker - go to ... window to another world beneath the waves, bubbling up on the seafloor with petroleum from deep below. A hydrocarbon seep in the Gulf of Mexico emits a viscuous petroleum - much like asphalt. This sounds somewhat familiar - the tar traps in California spring to mind (but these are above sea level). Most life forms that inhabit such seeps, for exampel mussels and crabs, depend on micro-organisms that oxidise the petroleum compounds. Hydrocarbons are an energy souce for microbes. In turn, microbial biomass is a food source for a diverse community of tube worms, mussels, crabs and shrimps. An estimated one third of microbes are hidden away, unseen by humans (and their microscopes). These ones are buried in sediments. The deep biosphere bubbles up to the surface of the sea floor along with petroleum reservoirs. A new study confirms that petroleum seeps are a conduit for transporting life from deep inside the earth to the sea floor after analysing 172 sediment samples that had been collected in a survey for the oil industry. A fraction of the samples contained gaseous hydrocarbons - the chief components of oil and natural gas. Instead, they mostly harboured distinct microbial life forms (such as bacteria and archaea).

A similar story is at ... hundreds of towering hydrothermal chimneys have been discovered on the sea floor off the coast of Washington State. The towers belch superheated liquid warmed by magma deep inside the earth. An authonomous diving robot captured the vents on camera. The towering spires and hydrothermal vents are locted at the bottom of the Juan de Fuca Ridge - 500 vents within a 9 mile stretch (one miles wide). Back in 2019 we were told hydrothermal vents triggered massive phytoplanktonic blooms. Do we have a clue here on to what causes chalk to form? (see ).