Remember the brine lake within the Gulf of Mexico? There’s another one in the Mediterranean Sea, called the L’Atalante basin – so deeply briny and lacking in oxygen that nothing can live there.
Until, as NewScientist‘s Colin Barras (21 January 2017, paywall) reports, someone took a sample and found life.
It was a shock, then, when biologist Roberto Danovaro scooped up samples from the bottom of this briny pool and found a thriving community of microscopic animals living there. The discovery went against everything we thought we knew about animal life and its reliance on oxygen.
It’s so shocking that some biologists think an error was made during the sampling process. But, interestingly enough, this discovery – once confirmed – ties in with observations going back to the origin of life, when oxygen was a rare molecule indeed.
… in 2014, Daniel Mills and Donald Canfield at the University of Southern Denmark in Odense set about investigating how much oxygen real primitive animals need. They began by collecting living breadcrumb sponges from well-oxygenated water off the Danish coast, a relevant test case because sponges are one of the earliest animals to have evolved. Then the researchers carted them back to their lab and did their best to suffocate them.
Over several days they reduced their oxygen supply, first to 70 per cent of current atmospheric levels, then 50 per cent, then eventually to 5 per cent. Even then, the sponges clung to life, with one even seeming to grow slightly (PNAS, vol 111, p 4168). It suggested that [Bruce] Runnegar’s calculations [indicating ancient worms needed very little oxygen] pointed the right way: simple animals could have coped with ancient oxygen levels.
This obviously has the potential to change our understanding of life’s history from day one, as well as biological processes today – and both might have practical consequences.
