The search for signs of life on Mars needs a bit of a rethink, scientists argue in a new study.

A popular strategy calls for investigating spots where waterborne sediment accumulated long ago, like the ancient lake-bed environment that NASA's Curiosity rover discovered inside Mars' 96-mile-wide (154 kilometers) Gale Crater. 

Here on Earth, such ancient habitats have preserved bountiful evidence of ancient life — but that doesn't mean the same will hold true on the Red Planet, according to the study team, which was led by Joseph Michalski, an associate professor in the Department of Earth Sciences at The University of Hong Kong. [The Search for Life on Mars (A Photo Timeline)]

"Mars is not Earth," the researchers wrote in the study, a "Perspectives" piece that was published online today (Dec. 18) in the journal Nature Geoscience

"We must recognize that our entire perspective on how life has evolved and how evidence of life is preserved is colored by the fact that we live on a planet where photosynthesis evolved," they said. "Even if photosynthesis did evolve on Mars, questions remain as to how successful surface life would have been, and whether evidence of that life could have been captured in the sedimentary record."

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