<p>I have learned that:     </p>

<ul>
<li>coral reefs are made up mostly of calcium carbonate </li>
<li>coral reefs are mainly distributed in the tropical zone</li>
<li>The calcium carbonate will be decomposed in the reaction as follows:<br>
$$CaCO_3 + H_2CO_3 -&gt; Ca^{2+} + 2HCO_3^-$$ </li>
</ul>

<p>Thus this reaction will be promoted in the environment with low pH. </p>

<p>The ocean in the tropic zone should have lower acidity (higher pH) for the coral reef to exist.</p>

<p>But in my opinion, the pH in the ocean is determined by the dissolution of CO2, and this process might be promoted in higher temperature?</p>

<p>How to explain this issue?</p>

CC BY-SA 3.0
2017-12-18T07:19:58.727Z
Isn't this decomposition under low pH responsible for the dying of coral reefs?
daniel.heydebreck
CC BY-SA 3.0
2017-12-18T08:23:38.580Z
However, the coral reefs are only distributed in the tropic area (30$^oN$-30$^oS$ ) at high temp (> 20$^oC$) over the distant ages.
Han Zhengzu
CC BY-SA 3.0
2017-12-22T18:08:40.600Z
I'm sure that there isn't any one answer to this. The *whole* ocean is decidedly not homogeneous. So surface water in the middle of the ocean, surface water near a coral atoll, deep water in the Marianas Trench, and ocean water near a black smoker are all very different.
MaxW
<geology><ocean><climate><geochemistry><carbon>
What controls the acidity of the ocean?
Han Zhengzu
# What controls the acidity of the ocean?

(Asked by: username_0 on 2017-12-18)

I have learned that:

* coral reefs are made up mostly of calcium carbonate
* coral reefs are mainly distributed in the tropical zone
* The calcium carbonate will be decomposed in the reaction as follows:  
  $$CaCO\_3 + H\_2CO\_3 -> Ca^{2+} + 2HCO\_3^-$$

Thus this reaction will be promoted in the environment with low pH.

The ocean in the tropic zone should have lower acidity (higher pH) for the coral reef to exist.

But in my opinion, the pH in the ocean is determined by the dissolution of CO2, and this process might be promoted in higher temperature?

How to explain this issue?

**Tags:** geology, ocean, climate, geochemistry, carbon

> **Comments:**
> **username_1**: Isn't this decomposition under low pH responsible for the dying of coral reefs?  
> **username_0**: However, the coral reefs are only distributed in the tropic area (30$^oN$-30$^oS$ ) at high temp (> 20$^oC$) over the distant ages.  
> **username_2**: I'm sure that there isn't any one answer to this. The *whole* ocean is decidedly not homogeneous. So surface water in the middle of the ocean, surface water near a coral atoll, deep water in the Marianas Trench, and ocean water near a black smoker are all very different.  

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## 0 answers

