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Accidentally purifying the oceans

Posted: Tue Mar 27, 2018 6:37 am UTC
by jseah
Assuming by some means (oops setting on a terraformer? Lazy caster making a self-replicating water purifying spell to skip work at the water reclamation plant?), overnight, all of Earth's oceans are terraformed into freshwater.

This does not remove existing organisms, etc. but instantly, the salinity of Earth's oceans drops to <0.1%. The volume does not change. (said spell might add or remove water so as to maintain that volume when removing the salt)


So first off, I expect most of the ocean life to just straight up die. What could survive this? Algae? How fast would the oceans be recolonized?

Apart from the obvious ecosystem damage, are there any weather or strange effects that could be expected? Polar ice cap suddenly expanding?

How long would it take for the salt content to start coming back from erosion and such?

Re: Accidentally purifying the oceans

Posted: Wed Mar 28, 2018 6:52 pm UTC
by eran_rathan
Well, for one, the entire climate would be incredibly fucked. Read up on thermohaline circulation, its responsible for Northern Europe & parts of Canada being habitable, as well as keeping a lot of the global climate stable. Its also very sensitive to changes in temperature & salinity, the last major meltwater pulse caused a minor ice age (Younger Dryas Event, probably caused by the melting of Lake Agassiz & the Laurentide Ice sheet).

in short, it would be rather bad - possibly Snowball Earth bad.

Re: Accidentally purifying the oceans

Posted: Wed Mar 28, 2018 6:53 pm UTC
by eran_rathan
Also, you'd have an issue of oxygen, as most of the oxygen/photosynthesis happens in the ocean, which means that you could very easily have mass asphyxiations of terrestrial creatures, like humans, that like to live at low elevations.

Re: Accidentally purifying the oceans

Posted: Wed Mar 28, 2018 8:15 pm UTC
by Xanthir
I expect the immediate mass-extinction in the oceans, and attendant rotting, would render the atmosphere completely unlivable for most land-based organisms, yeah. (And whatever water-based stuff survived the salinity change would asphyxiate due to the decomposition using up all the oxygen, so more mega-death.)

In other words this would probably result in extinction of nearly all life on earth.

Re: Accidentally purifying the oceans

Posted: Thu Mar 29, 2018 7:03 am UTC
by Eebster the Great
Also, production of sea salt and vinegar potato chips would plummet.

Re: Accidentally purifying the oceans

Posted: Thu Mar 29, 2018 7:21 am UTC
by jseah
Xanthir wrote:I expect the immediate mass-extinction in the oceans, and attendant rotting, would render the atmosphere completely unlivable for most land-based organisms, yeah. (And whatever water-based stuff survived the salinity change would asphyxiate due to the decomposition using up all the oxygen, so more mega-death.)

In other words this would probably result in extinction of nearly all life on earth.

Would plants not survive? Since they produce oxygen after all.

Re: Accidentally purifying the oceans

Posted: Thu Mar 29, 2018 12:57 pm UTC
by jewish_scientist
They would suffer from the collapse of the ecosystems they are part of though.

Re: Accidentally purifying the oceans

Posted: Thu Mar 29, 2018 3:24 pm UTC
by jseah
Ah true. So it's all down to freshwater algae.

Re: Accidentally purifying the oceans

Posted: Thu Mar 29, 2018 3:39 pm UTC
by freezeblade
jseah wrote:Ah true. So it's all down to freshwater algae.


I imagine that ultimately fish that can survive in fresh/salt water (brackish) will adapt to fill in the resulting fresh water oceans first. Especially true with the freshwater algae spreading out to sea from river deltas first, providing oxygen to these areas of water.

Re: Accidentally purifying the oceans

Posted: Thu Mar 29, 2018 4:32 pm UTC
by Eebster the Great
Brackish ecosystems can be fragile. The devastation of killing virtually all marine organisms is not something we have ever seen before. Some life presumably would survive, but I doubt vertebrates would be on the list.

Re: Accidentally purifying the oceans

Posted: Thu Mar 29, 2018 6:38 pm UTC
by Sableagle
Now, if you accidentally "purified" someone's blood, that'd be a much, much more localised extinction event.