Cockell, Charles S.; Kaltenegger, Lisa and Raven, John A.
|DOI (Digital Object Identifier) Link:||http://doi.org/10.1089/ast.2008.0273|
|Google Scholar:||Look up in Google Scholar|
On Earth, photosynthetic organisms are responsible for the production of virtually all the oxygen in the atmosphere. On land, vegetation reflects in the visible and leads to a “red edge,” which developed about 450 million years ago on Earth and has been proposed as a biosignature for life on extrasolar planets. However, in many regions on Earth, particularly where surface conditions are extreme—in hot and cold deserts, for example—photosynthetic organisms can be driven into and under substrates where light is still sufficient for photosynthesis. These communities exhibit no detectable surface spectral signature to indicate life. The same is true of the assemblages of photosynthetic organisms at more than a few meters' depth in water bodies. These communities are widespread and dominate local photosynthetic productivity. We review known cryptic photosynthetic communities and their productivity. We have linked geomicrobiology with observational astronomy by calculating the disk-averaged spectra of cryptic habitats and identifying detectable features on an exoplanet dominated by such a biota. The hypothetical cryptic photosynthesis worlds discussed here are Earth analogues that show detectable atmospheric biosignatures like our own planet but do not exhibit a discernable biological surface feature in the disc-averaged spectrum.
|Item Type:||Journal Article|
|Copyright Holders:||2009 Mary Ann Liebert, Inc.|
|Keywords:||atmospheric gases; bioastronomy; extrasolar terrestrial planets; photosynthesis; planetary atmospheres|
|Academic Unit/Department:||Science > Physical Sciences
|Interdisciplinary Research Centre:||Centre for Earth, Planetary, Space and Astronomical Research (CEPSAR)|
|Depositing User:||Charles Cockell|
|Date Deposited:||10 Nov 2009 09:55|
|Last Modified:||15 Jan 2016 12:03|
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