Naked Science Forum

Life Sciences => The Environment => Topic started by: Tintin_Triton on 15/04/2010 18:38:38

Title: Why are the seas slightly basic?
Post by: Tintin_Triton on 15/04/2010 18:38:38

Courtsey, The Scientific American, April 2010, I found out that the seas [O8)] are a little basic. I think their pH varies from 8.0 to 8.4. However, this is contradictory to many other processes, such as absorption of CO₂ causes a slight formation of Carbonic acid, in equilibrium.

So, my question is, again [:D], why are oceans (an seas) slightly basic? 

Title: Why are the seas slightly basic?
Post by: Bored chemist on 15/04/2010 19:15:25

If they were acid the white cliffs of Dover would dissolve to neutralise them.
http://en.wikipedia.org/wiki/White_Cliffs_of_Dover
There are other big carbonate deposits too.

Title: Why are the seas slightly basic?
Post by: Tintin_Triton on 17/04/2010 10:02:04

Well, true, but just why are they basic, and not acidic, so that we do not see the white cliffs of dover dissolving to produce a fantastic display of bubbles?

Title: Why are the seas slightly basic?
Post by: LeeE on 17/04/2010 16:32:25

It would seem that the oceans are becoming more acidic:

http://en.wikipedia.org/wiki/Ocean_acidification (http://en.wikipedia.org/wiki/Ocean_acidification)

but I don't know why/how they initially became basic in the first place.  However, I would guess that the ambient levels of atmospheric CO2 were too low to reach saturation with the result that most of the CO2 that was absorbed combined with calcium to form the carbonate exploited by shellfish.  Just a guess though.