Slashdot Mirror
New Sub Dives To Crushing Depths
University of Washington Scientists are reporting that they have a new autonomous underwater vehicle that increases both the attainable depth and duration of deployment over current submersibles. Weighing in at just under 140 pounds, the "Deepglider" is able to stay out to sea for up to a year and hit depths of almost 9,000 feet. "Deepglider opens up new research possibilities for oceanographers studying global climate change. The glider's first trip revealed unexpected warming of water near the ocean floor, and scientists are interested in studying whether the temperatures are related to global warming."
The average heat flux from the earth is less than 0.1W/m2. Compare that to ~ 1000 W/m2 for the sun. Sure, it varies all over the place (see: volcanoes, etc.), but it's not a no-brainer where any heat anomalies the glider detected came from. In general, the deep ocean is quite cold because of that whole thermal expansion thing (also note that seawater is densest a few degrees above freezing (~4 deg C, if I recall). So heating from the bottom tends to cause convection.
You'll note that the scientists quoted don't mention global warming; they are excited to see stuff that they didn't expect. That's good enough to satisfy their intellectual curiosity & need to come up with new and interesting grant proposals.
You'll also notice that scientists in general don't sell newspapers or magazines. It's the journalists whose job it is to butcher the science to sell newspapers and magazines.
Finally, the oceans are very much tied up in our little carbon experiment. A good bit of any extra heat that is trapped in the atmosphere will go into the oceans. Also, a lot of the CO2 that we've emitted is already going into the oceans, which leads to ocean acidification. This is the rate of carbonic acid input (that's CO2 + H2O H2CO3 H+ + HCO3-) is much higher than the ocean can buffer it with CaCO3 (which buffers effectively, but only on very long time scales). In the meantime, hope you don't like coral.
Simple Unexpected Concrete Credible Emotional Stories
I'm working in a buoyancy related problem so I have to point this out. From the full article: "When pressure compresses a hull in a traditional glider, it gains buoyancy and requires more energy to control." If it's compressed, the volume shrinks, it gains density and loses buoyancy.
That is probably the very question they're trying to answer.
Ocean water is not stagnant and there are currents that mix surface water with warmer water in places where the surface water is colder (and denser) than the deeper water.
The reason this matters, from TFA, is that this is a glider, not a submarine. It's cheaper, lighter, and more energy efficient than dropping a big ball to the bottom of the ocean. This thing can drive around and look at stuff very similarly to how a non-crush depth submersible could do.
stuff |