Microbes deep beneath the Pacific ocean consider inactivity to new heights. They are so slow on the uptake of nutrients from their environment that they barely classify as alive. Their extremely existence could aid define the limit amongst life and death.
Paradoxically, however, they may possibly also be amongst the oldest living organisms on Earth.
Everything takes place slowly in the North Pacific gyre, one of the 5 largest ocean gyres in the planet. Sand and mud washing off the continents hardly ever finds its way there, so the seafloor accumulates sediment at a sluggish rate. The clay just 30 metres below the seafloor was deposited 86 million years ago, practically 20 million years before Tyrannosaurus rex graced the Earth.
That clay is made up of so little energy in the type of nutrients that it should be incapable of supporting a living community. Microbes have been discovered in other, only slightly far more energy-wealthy communities under the seafloor, although.
In a bid to hone in on the reduce energy limits for life, Hans Røy at Aarhus University in Denmark probed the clays beneath the North Pacific gyre. Beneath the microscope, he located a community made up of bacteria and single-celled organisms known as archaea in vanishingly little numbers.
“There are only 1000 tiny cells in 1 cubic centimetre of sediment, so finding just one is actually like hunting for a needle in a haystack.”
Reduced limit for life
The microbes rely on oxygen, carbon and other nutrients in their deep environment to live, but Røy’s team identified that carbon is so limited that the cells respire oxygen 10,000 times slower than bacteria in lab-grown cultures.
Røy thinks the microbial community is so sparse, and the metabolic prices so very low, that the nutrient levels almost certainly represent the bare minimal essential to hold cellular enzymes and DNA working. “It looks like we have reached the absolute reduce limit for the metabolism of cells,” he says.
Yuki Morono at the Japan Agency for Marine-Earth Science and Technologies in Nankoku, Japan, lately studied equivalent reduced-energy microbial communities beneath the Pacific seafloor near Japan. Under a microscope, he says, the microbes show couple of indicators of life. “They seem to be dead by our time scale.
Sources and more information:
• Ancient life, millions of years old and barely alive, found beneath ocean floor
Personal Post Their strategy for staying alive is to be barely alive at all. Their metabolism is dialed down to almost nothing, an adaptive advantage in a place with so few resources. The bacteria that survive are the ones that can satisfy themselves with minute traces of oxygen and a parsimonious diet of organic material laid down millions of…
• Buried ocean microbes exist at limit between life and death