100 million-year-old sea microbes are alive and thriving, study finds

Above is a fluorescence microscopy image of 13 million-year-old microbes after separation from subseafloor sediment and sorting.

(CNN)Humans can go without food for about three weeks before the effects of starvation begin to kill them.

Some microbes deep underneath the seafloor have us beat: They can survive with barely any sustenance for more than 100 million years.
These microorganisms live more than 18,000 feet underneath the ocean surface — in an area so deep it's called the subseafloor, below the seafloor.
These sparse microbial populations exist in the slowly accumulating oxygen-filled sediment of the South Pacific Gyre, located within the South Pacific Ocean and bound by the equator, Australia, the Antarctic Circumpolar Current and South America, according to a study published Tuesday in the journal Nature Communications.
Marine microbes are tiny, single-celled microorganisms that live in the ocean and account for more than 98% of the total mass of organisms living within the ocean.
The area, part of the Earth's system of rotating ocean currents, doesn't have a lot of food to feed almost anything. It's relatively low in plant nutrients but contains abundant oxygen in the deeper parts of the subseafloor.
Because the center of the South Pacific Gyre is the site on Earth farthest from all land and productive ocean regions, it's called the "oceanic pole of inaccessibility" and is regarded as Earth's largest oceanic desert.
There are five major gyres, which are large systems of rotating ocean currents. The ocean churns up various types of currents. Together, these larger and more permanent currents make up the systems of currents known as gyres.
It's not a spot where most life would thrive, although microbes below the seafloor were known to be present in the South Pacific Gyre sites. Luckily for the microbes, their population wasn't limited by the availability of nitrogen and iron or other dissolved major inorganic nutrients necessary for the growth of living things.

Life beneath the seabed