It is the ocean floor , and not the continents, that is the most precious geological spectacle on our planet and where the slow evolution of the earth’s crust can be clearly seen . From mid-ocean ridges – ridges reaching 3,000 meters in the middle of the oceans – a new sea floor slowly emerges as tectonic plates shift. However, this does not only happen at the bottom of the sea. In East Africa, on the Serengeti plains and in the Lake District of Kenya and Tanzania , what will be a new sea in millions of years is forming . Something similar to what happened when Africa broke away from Arabia, which created the Red Sea, will happen: in less than a week, in September 2005, the Afar desert in Ethiopia, the youngest segment of this new sea, widened 8 meters .
At the bottom of the ocean we also find the most dangerous geological places on the planet . One of them is called 9º North, an area that sits on the ridge of the Eastern Pacific, on the limit of the Pacific Plate -the largest on the planet-, and the Cocos Plate, one of the smallest and located off the coast of Acapulco and Puerto Vallarta. There the eruptions and earthquakes, invisible under the waves, are our daily bread. As those two plates move 11 to 12 cm apart each year, molten lava bubbles up from inside to fill the hole. And then 9th North trembles, hit by 2-3 earthquakes a day. But sometimes its heartbeat speeds up, like in 1991, when it was subjected to a terrible volcanic eruption. In the space of two hours, roughly the equivalent of 400,000 truckloads of lava spread across the ocean floor. A decade later, in 2003, the first dozens of earthquakes, which later became hundreds of them, broke the ocean floor daily, heralding the earthquake to come. On January 22, 2006 , the hecatomb happened: 250 earthquakes per hour (4 per minute) destroyed the seabed . The lava rose from the depths and spread for almost 2 km. This time of upheaval, which builds a new ocean at 9º North, also renews life with water enriched by chemical reactions between rock and water.
It all starts when frozen water seeps through the cracked sea floor, heating up and acidifying. At 350 ºC it drags copper, iron and zinc from the surrounding rocks and turns into a corrosive liquid that we would hardly identify with that liquid that quenches our thirst. The water rises full of metals in the form of a boiling jet that makes its way until it hits the frozen water of the ocean floor. A shower of metals is then produced, causing chimneys to grow around the opening . What is surprising is that life emerges from this poisonous drink, since it is more like hell than paradise. The temperature of these fumaroles reaches 400 ºC and the water is scented with sulfur. Hydrogen sulfide, poisonous to humans, is heaven-sent manna for the bacteria that live there, with which they grow rapidly and eventually form a dense bacterial mat on the newly formed rock . Scientists call this place, not without reason, the Phoenix.
Little by little Fénix fills with life : clams, mussels, tube worms, crabs, limpets… There is food for everyone. Tube worms can grow up to 600 in a single group. In the five-foot-long tube, white and topped by what looks like a red feather, lives a well-fed worm that can grow 34 inches in a year: it ‘s among the fastest-growing marine invertebrates known . They are well nourished, although they do not have a mouth or digestive system.
On the surface, plants use the Sun’s energy to make carbohydrates that are then eaten by animals. Deep in hydrothermal vents it is chemosynthesis , not photosynthesis, that is the basis of life . The bacteria that live in the tube worms use the hydrogen sulfide that comes out of the fumarole to make food for their host. Under other circumstances this effort would be lethal, as the high concentrations of hydrogen sulfide would kill most animals, but tube worms thrive in this deadly combination of gases. What happens is that the zinc in your hemoglobin temporarily binds to the hydrogen sulfide and carries it to the bacteria without killing the worm. A perfect example of symbiosis in an extreme environment.
