As a small background to the project I am working on: I am currently doing my Masters of Architecture in Copenhagen, and we are designing devices to bring on our expedition to the North Pole, and I am harnessing salt water to pump through salt water batteries.

My question is then: What kind of pump do I need to pump water up 2 meters? I don't need much water coming up at once, just needs to be constant. I am also looking for the most energy efficient way of doing this, any know of something?

Any help is much appreciated!