BBC Focus Magazine

[Healerman]

[quote][Gigantic amoebas have been found in the Mariana Trench, the deepest region on Earth.
During a July 2011 voyage to the Pacific Ocean chasm, researchers with Scripps Institution of Oceanography at UC San Diego and National Geographic engineers deployed untethered landers, called dropcams, equipped with digital video and lights to explore the largely mysterious region of the deep sea
/quote]

http://www.msnbc.msn.com/id/44998895/ns ... e-science/

This should add to the speculations on what mightbe found in other (possible) locations in our solar system, and indeed in others.

[M Paul Lloyd]

Xenophyophores are noteworthy for their size, with individual cells often exceeding 4 inches (10 centimeters), their extreme abundance on the seafloor and their role as hosts for a variety of organisms.

Four Inches! Well no need for a microscope with them then?

Its also quite chilly down there.

[MrIsaksson]

Its also quite chilly down there.

what i find most interesting with that graph is that the temperature starts to rise at 1000 m...

In my mind i though it hit the lowest temperature much earlier and stayed like that through out the depth..

[M Paul Lloyd]

Or you could view it as the temperature dropping quite dramatically from around 300 metres?

Either way I have to admit it is a bit biased towards more tropical regions as I can confirm that our bit of the North Sea rarely reaches 22 degrees C even at the height of summer.

[Jamie]

Probably something to do with how far light gets down too.

[Healerman]

The thing I find interesting about that graph is that water is supposed to hit maximum density at 4ºC. This appears to be at 2500m, yet the temperature keeps dropping to about 2.5ºC at 4500m, according to the graph. Unless the water at 4500m is compressed, which I thought was impossible, it ought to be less dense than water at 4ºC and should rise.

Can anyone cast light on this?

[Flakkarin]

Don't forget it's not just temperature that affects the density of seawater: salt content is a big factor. I think colder water also holds more salt. That thermocline is only part of the story (salt content is the halocline, and the two combines are the pycnocline, or density profile:

http://www.hurricanescience.org/science/basic/water/) and also very general - different oceans have varying pycnoclines due to different water masses moving at different depths: