If tectonic plate movement stops, how will it affect the atmosphere?

Question

Will the oceans dry up?

Answer 1

Directly? Not at all. Plate movement does not directly affect either the atmosphere or the oceans.

Indirectly, now ...
Quite a lot.

Plate tectonics is in large part a function of thermal convection in the mantle. This would only stop if the interior of the planet cooled significantly. This interior cooling would also lead to the outer core solidifying, which would stop the inner core from spinning.

Since the relationship between the spinning iron inner core and the liquid iron outer core generates the Earth's magnetic field, which protects the atmosphere from being stripped away by the Solar Wind ...

Indirectly, if tectonic plate movement stopped, the Earth would come to resemble Mars. Our atmosphere would mostly be stripped away, and the oceans would evaporate. And we would all be dead - if we haven't already found somewhere else to live.

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edited for clarity

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Sorry Duff, but volcanoes don't account for any where near the majority of CO2 emissions. Volcanic sources release about 3% as much as the various anthropogenic sources - a bit less than just the industrial production of concrete.

In itself, tectonic activity has very little direct effect on the biosphere.

Incidentally, if surface gravity increased, it would result in greater stratification by density in the atmosphere, not less. The proportion of O2 in the lower atmosphere would increase. And the amount of thermal contraction that would accompany the cooling would be only few per cent. So even this change is negligible.

Answer 2

I did not realize the relationship between the magnetic field and the atmosphere. Good answer by skeptik. I DID know that the Earth's magnetic field blocks a lot of radiation and solar flares from reaching Earth. And, that prompts me to wonder what happens when the Earth's magnetic field reverses itself as it does regularly in the geologic record. I don't think that those have been linked to mass extinction events.

There's one other link I know about: Carbon dioxide and oxygen. The world's largest source of carbon dioxide is from volcanoes, and most volcanoes are associated with plate subduction zones. Then, plants and algae convert the CO2 to oxygen. So, volcanoes are actually the original source for the world's oxygen. (We conservative conspiratorialists like to keep all this a secret from Al Gore).

So, CO2 and O2 levels would decrease. I actually don't know where N2 comes from, which is the predominant gas in the atmosphere.

And then there's my own paleogravity theory. If, as skeptik suggested, the cessation of plate tectonic activity was associated with core cooling, then the Earth would also shrink in physical size, just like everything else that cools off. This would increase the gravity we feel on the surface of earth, due to the surface of the Earth being closer to its center of gravity. THAT would change the ratio of oxygen to nitrogen, because nitrogen is a little lighter than oxygen. The nitrogen would increase for the same reason that Jupiter can have an atmosphere of hydrogen, the lightest of all gases.

It would also cause lower-gravity organisms (such as dinosaurs), to experience reduced reproductive success against birds and mammals. (that's my own two cents, not accepted by mainstream science). That's where I get the username, "dinotheorist."

Answer 3

The ocean as this current status will will not dry up. The only way the oceans could dry is from an event from outer space. For example. if the earth were to move out orbit closer to the sun. The sun will eventually burn up the atomsphere and the oceans would dissappear into space.