I've heard it said that we know more about the surface of the Moon than we do about the deep oceans on the Earth.
I've never seriously attempted to find out how accurate this is (and honestly, don't know how you'd compare the two), but I suspect it's substantially correct. About seventy percent of the Earth's surface is covered by water, and given the difficulty of seeing what's down there -- even by remote telemetry -- it's no wonder we're still finding things in the ocean we never knew existed.
Take, for example, the study that appeared in Current Biology last week about the Clarion-Clipperton Zone. The CCZ is the region between the Clarion Fracture Zone and the Clipperton Fracture Zone in the central Pacific, with an area of about six million square kilometers. It contains several (apparently dormant or extinct) volcanoes, a number of submarine troughs of uncertain seismic activity, and a rough, mountainous topography.
The prevailing wisdom has been that most of the open ocean has relatively low biodiversity. To put it more simply, that there just ain't much out there. If you're in the middle of the ocean, any given cubic meter of water is unlikely to have many living things in it beyond single-celled plankton. And -- supposedly -- the floor of the deep ocean, with crushing pressures, no light, and constant temperatures just above the freezing point of water, is often pictured as being pretty much devoid of life except for the bizarre hydrothermal vent communities.
That concept of the deep oceans needs some serious re-evaluation. Last week's paper featured a survey of the abyssal life in the Clarion-Clipperton Zone, and found nearly six thousand species of animals...
...of which 92% were unknown to science.
The coolness factor of this research is tempered a little by the reason it was conducted. The CCZ is being studied because of its potential for deep-sea mining. The seafloor there has a rich concentration of manganese nodules, concretions of metal oxides and hydroxides (predominantly manganese and iron, with lower concentrations of other heavy metals), which are of immense value to industry. Add to that the fact that the CCZ is in international waters -- so, basically, there for whoever gets there first -- and you have a situation that is ripe for exploitation.
What makes this even more complex is that the metals in the nodules are used, amongst other things, for high-efficiency electronics, including renewable energy systems. The cost, though, might be the destruction of an ecosystem that we've only begun to study."There are some just remarkable species down there," said Muriel Rabone, of the Natural History Museum of London, who co-authored the study. "Some of the sponges look like classic bath sponges, and some look like vases. They’re just beautiful. One of my favorites is the glass sponges. They have these little spines, and under the microscope, they look like tiny chandeliers or little sculptures. There are so many wonderful species in the CCZ, and with the possibility of mining looming, it’s doubly important that we know more about these really understudied habitats."