Hydothermal Vents Edgartown School热液喷口埃德加敦学校.ppt

But without LIGHT.In TOTAL DARKNESS.(No chlorophyll either!) A process previously unknown to all of science, which we now call…CHEMOSYNTHESIS Look at some more video of these vents.(Click for video 2:00) Since 1977, dozens of other hydrothermal vents have been discovered at mid-ocean ridges around the globe. The discovery of hydrothermal vents at mid-ocean ridges is considered one of the most important scientific discoveries of the century.They have entirely changed the way we look at life on Earth. And beyond.We shall soon learn how.(Click here for video 5:24) * * * * * * * * * TheStrangeWorldofHydrothermal Vents Before you learn what they are, take a look at what they are.This is what a hydrothermal vent looks like.(Click here 2:49)/watch?v=J_jubgEzG9A In 1977, Dr. Robert Ballard led an expedition in search of the first hydrothermal vent to be discovered. He found them. But that is only the beginning of this historic journey. ALVIN First deep sea submersible. Built by WHOI (Woods Hole Oceanographic Institute). Our Vineyard neighbors! ALVIN was launched that day in 1977 near the Galapagos Islands, along a mid-ocean ridge, where scientists predicted they might finddeep-sea hydrothermal activity. And they found it.Chimneys spewing out what looked like black smoke.The scientists called them “black smokers.” These were underwater geysers, fueled by hot magma chambers just below the mid-ocean ridge. In some places, there are so-called “white smokers”, where the plumes contain different minerals. Conditions at the vents: Extreme temperatures (35oF - 750oF) [That’s almost freezing, to 4X hotter than boiling water!] Extreme pressure (3500 lbs/ in2) [That’s 240x the pressure we feel on the surface.] Poison gases, heavy metals. Absolutely no light. It was an amazing discovery.But more amazing than these remarkable vents… The place was teeming withlife…Strange life…Organisms never before seen by humans. Especially obvious were countless