Many Worlds

Tag: hydrothermal vents

2.5 Billion Years of Earth History in 100 Square Feet

October 19, 2017 / / 0 Comments

Scalding hot water from an underground thermal spring creates an iron-rich environment similar to what existed on Earth 2.5 billion years ago. (Nerissa Escanlar)

Along the edge of an inlet on a tiny Japanese island can be found– side by side – striking examples of conditions on Earth some 2.4 billion years ago, then 1.4 billion years ago and then the Philippine Sea of today.

First is a small channel with iron red, steaming and largely oxygen-free water – filled from below with bubbling liquid above 160 degrees F. This was Earth as it would have existed, in a general way, as oxygen was becoming more prevalent on our planet some 2.4 billion years ago. Microbes exist, but life is spare at best.

Right next to this ancient scene is region of green-red water filled with cyanobacteria – the single-cell creatures that helped bring masses of oxygen into our atmosphere and oceans.  Locals come to this natural “onsen” for traditional hot baths, but they have to make their way carefully because the rocky floor is slippery with green mats of the bacteria.

And then there is the Philippine Sea, cool but with spurts of warm water shooting up from below into the cove.

All of this within a area of maybe 100 square feet.

It is a unique hydrothermal scene, and one recently studied by two researchers from the Earth-Life Science Institute in Tokyo – evolutionary microbiologist Shawn McGlynn and ancient virus specialist Tomohiro Mochizuki.

They were taking measurements of temperature, salinity and more, as well as samples of the hot gas and of microbial life in the iron-red water. Cyanobacterial mats are collected in the greener water, along with other visible microbe worlds.

Shawn McGlynn, associate professor at the Earth Life Science Institute in Tokyo scoops some iron-rich water from a channel on Shikine-jima Island, 100 miles from Tokyo. (Nerissa Escanlar)

The scientific goals are to answer specific questions – are the bubbles the results of biology or of geochemical processes? What are the isotopic signatures of the gases? What microbes and viruses live in the super-hot sections? And can cyanobacteria and iron co-exist?

All are connected, though, within the broad scientific effort underway to ever more specifically understand conditions on Earth through the eons, and how those conditions can help answer fundamental questions of how life might have begun.

“We really don’t know what microbiology looked like 2.5 billion or 1.5 billion years ago,” said McGlynn, “But this is a place we can go where we can try to find out.… Read more

Ocean Worlds: Enceladus Looks Increasingly Habitable, and Europa’s Ocean Under the Ice More Accessible to Sample

April 13, 2017 / / 0 Comments

NASA’s Cassini spacecraft completed its deepest-ever dive through the icy plume of Enceladus on Oct. 28, 2015. (NASA/JPL-Caltech)

It wasn’t that long ago that Enceladus, one of 53 moons of Saturn, was viewed as a kind of ho-hum object of no great importance.  It was clearly frozen and situated in a magnetic field maelstrom caused by the giant planet nearby and those saturnine rings.

That view was significantly modified in 2005 when scientists first detected signs of the icy plumes coming out of the bottom of the planet.  What followed was the discovery of warm fractures (the tiger stripes) near the moon’s south pole, numerous flybys and fly-throughs with the spacecraft Cassini, and by 2015 the announcement that the moon had a global ocean under its ice.

Now the Enceladus story has taken another decisive turn with the announcement that measurements taken during Cassini’s final fly-through captured the presence of molecular hydrogen.

To planetary and Earth scientists, that particular hydrogen presence quite clearly means that the water shooting out from Enceladus is coming from an interaction between water and warmed rock minerals at the bottom of the moon’s ocean– and possibly from within hydrothermal vents.

These chimney-like hydrothermal vents at the bottom of our oceans — coupled with a chemical mixture of elements and compounds similar to what has been detected in the plumes — are known on Earth as prime breeding grounds for life.  One important reason why is that the hydrogen and hydrogen compounds produced in these settings are a source of energy, or food, for microbes.

A logical conclusion of these findings:  the odds that Enceladus harbors forms of simple life have increased significantly.

To be clear, this is no discovery of extraterrestrial life. But it is an important step in the astrobiological quest to find life beyond Earth.

Now the Enceladus story has taken another decisive turn with the announcement that measurements taken during Cassini’s final fly-through captured the presence of molecular hydrogen.

To planetary and Earth scientists, that particular hydrogen presence quite clearly means that the water shooting out from Enceladus is coming from an interaction between water and warmed rock minerals at the bottom of the moon’s ocean– and possibly from within hydrothermal vents.

These chimney-like hydrothermal vents at the bottom of our oceans — coupled with a chemical mixture of elements and compounds similar to what has been detected in the plumes — are known on Earth as prime breeding grounds for life. … Read more

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