The Mysterious Ocean
From space Earth is a glass marble swirled blue and white. The white cloud cover shows change and active weather processes, while the blue announces to onlookers million miles away the single most important defining characteristic of our home planet: it is covered with water. The seas cover roughly three quarters of Earth’s surface. The oceans also contain the majority of places on the planet where things can live. This is because the depth combined with the area covered provides a much more three dimensional habitat than the land. Rain forests have three dimensionality in the various layers of tree canopy, but the scale of that (tens of meters) is minor compared to the ocean depths. 80% of the biosphere (the portion of the planet where living things are found) is actually in the ocean below 1000 meters.
These deep sea environments are very challenging to study because we can't see them. The Hubble space telescope can see galaxies 15 billion light years away, but satellites can not take pictures of the bottom of the ocean because “seeing” through the water is difficult, since light only penetrates the top 50 meters. We have ways of sensing the topography of the ocean floor using satellites and sonar aboard ships, but we can not see whats there without sending down a some type of camera. This means that there are many snapshots, and make guesses about what’s between them. How many photographs would you need to understand what it was like on another planet? How many would you need to see before you felt like you had seen it all? We have more detailed maps of the surface of the Moon or even Mars than we do the sea floor. Anyone with internet connection can go to Google Mars and see images of individual craters canyons and mountains on Mars, but Google Earth can only take us under water in specific areas that have been well documented.
One way to think of how well we know what’s at the bottom of the ocean is this: If aliens found earth and wanted to see what it was like without leaving their space ship, they might take a sample from the surface but lowering some sort of bucket or jar and seeing what they pulled up. If they sampled somewhere over the United States and pulled up a bucket of corn, their best guess might be that the whole U.S. is one big cornfield. That is a silly analogy, but roughly illustrates how well we understand the deep ocean know. We know where the major under sea mountain ranges are, and we know that 80% of the worlds volcanic activity happens underwater, but the specific details are few and far between, literally. Scientists are constantly discovering new species in the deep sea, and they regularly find types of organisms that are very unique and that we know almost nothing about (this type of discovery happens only rarely on land). They are still discovering dramatically different types of ecosystems that were unimaginable only a few years ago. One discovery in particular stands out...