The Jacques Cousteau iPhone app, an electric camper, musical tree rings and more in our look at the web this week

The United Nations is hosting a design competition in Europe, tasking people to design ads supporting water conservation efforts. As part of “The Future We Want” initiative for the Rio+20 conference, the DropbyDrop campaign aims to inspire individuals to motivate one another to save the planet’s “most precious resource.” Entries may be submitted through 29 February 2012.