California received a blow to its water supplies earlier this month when the feds reduced the amount of Colorado River water diverted to the state. Now, the ever-thirsty Golden State is turning to a different potential source to solve its water woes: the Pacific Ocean. Seawater can be converted to freshwater through desalination, a process that was once viewed as prohibitively expensive but could become more affordable as new technologies emerge and shrinking water supplies boost demand. Environmentalists, however, worry that more affordable desalination could spell trouble for marine ecosystems. For every two gallons of water filtered by the process, one is pumped back into the sea; that one contains highly elevated salt concentrations, which can kill or harm small marine creatures. Scientists are still studying the impact of the process on dolphins and other marine mammals, and California’s plans to develop five desalination plants will be subject to environmental review.