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hi i'd like to tell you about some

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recent numerical modeling work examining

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stable isotopes on enceladus

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as water vapor and other gases erupt

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from the ocean light isotopes erupt more

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easily which should make the plume

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isotopically lighter than the ocean and

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make the ocean isotopically heavier over

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time

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for carbon and co2 the ocean is probably

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only slightly heavier than the plume but

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if the current plume eruption rates have

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persisted over long time scales then the

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co2 in the ocean may have been

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isotopically lighter in the past

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if we assume methane started with the

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same isotopic ratio as co2 then a

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fractionation between these gases in the

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ocean can emerge over long time scales

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however the maximum we see here around

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two and a half per ml is still much

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smaller than biological fractionation

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so this process alone should not create

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false positive biosignatures

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the d to h ratio of water may have

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evolved similarly but even with

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persistent long-term eruption the d-h

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ratio of enceladus still seems

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consistent with an origin from