As landfills fill up we are always looking for new and clever ways to sweep our trash under the rug. The vast oceans are a tempting frontier … but how do we use them without polluting them? A lot of waste that runs into our waters becomes habitats for fish and other sea life but only recently have people begun to think about doing this intentionally. From a set of subway cars to an entire aircraft carrier here are a few projects that take recycling to new depths – not to mention above-water reuses of sea bases by pirate radio operators and micronation founders.

(Images via: NYPress, NJScuba and Inhabitat)

Who would have thought that hundreds of old subway cars could find a second life with exotic marine passengers? Starting with a few dozen retired New York City cars, this East Coast habitat project is expected to unload hundreds of cars by the time it is done. The dumped vehicles can support thriving sea life in, on and around them within a mere six months and help bring back communities of depleted oceanic animals.

The USS Oriskany is one of a number of gigantic vessels that has been systematically sunk by the US Navy in order to create massive artificial underwater reefs. Weighing nearly 50,000 tons and housing dozens of species, the vessel had to be thoroughly cleaned before it could be sent under. While the oceans can’t be a dumping ground for every kind of waste they are a great place for objects like this that can be effectively assimilated into local ecosystems and promote rather than disturb sea life.

If we take a somewhat looser definition of ‘marine habitat’ there are a host of aquatic structures that have been adaptively used in all kinds of created ways – but by and for people rather than sea animals. The army sea forts shown above have been converted into everything from luxury hotels to pirate radio stations and even micronations. For more information about these amazing structures click here.