Water Quality B/C

[caseyotis]

I only saw a few multiple-choice questions on estuaries. I predict that they'll be on the state test, though.

[Blwrunner]

Okay good. I was worried that there was going to be a large diagram on the test. That was the only change they made on the event this year...correct?

[caseyotis]

Okay good. I was worried that there was going to be a large diagram on the test. That was the only change they made on the event this year...correct?

I believe so. I couldn't tell any difference, and I got first both times... But that was the regionals test. I haven't seen the states test before.

[Azismith]

Does temperature affect pH? If it does, does it acidify the water? Also, if it does, why does this happen?

[caseyotis]

Does temperature affect pH? If it does, does it acidify the water? Also, if it does, why does this happen?

As temperature of water rises, it becomes more acidic (pure water is only at a pH of 7 at 25 degrees Celsius). This is due to the breakdown of water molecules into their original constituents (hydrogen and oxygen). Producing more hydrogen than oxygen acidifies the water. I don't know if this would be on a test though, but it is a very good question.

[Azismith]

What happens when you factor aquatic life into the picture? As the temperature of the pond increases, wouldn't the metabolic rate, and thus the respiration of the organisms in the pond increase? This would create more carbon dioxide, which would react with the water to form carbonic acid (I believe that it is carbonic). But, as the temp. increases, the pond can hold fewer gases (is this right?), so the CO2 would escape from the pond w/out acidifying it. Or, the plants in the pond would convert this to DO, which wouldn't affect the pH (at least not directly). So, would the temperature/pH relationship acidify at first, then level out? Or is that completely the wrong chain of thought? Thank you!

[caseyotis]

What happens when you factor aquatic life into the picture? As the temperature of the pond increases, wouldn't the metabolic rate, and thus the respiration of the organisms in the pond increase? This would create more carbon dioxide, which would react with the water to form carbonic acid (I believe that it is carbonic). But, as the temp. increases, the pond can hold fewer gases (is this right?), so the CO2 would escape from the pond w/out acidifying it. Or, the plants in the pond would convert this to DO, which wouldn't affect the pH (at least not directly). So, would the temperature/pH relationship acidify at first, then level out? Or is that completely the wrong chain of thought? Thank you!

I... I have no idea. But I am fairly certain that you shouldn't go into that much detail, especially in Div. B!
I believe the acidification is minimal and not very important, but you can research more online. It's all too complicated for me.

[silentsage]

From what I've found, and a test I took, I thought that pH naturally decreases with time during the day because organisms undergoing photosynthesis released CO2, an acid, thereby lowering pH, which rises back up overnight. The temperature of water should not affect the amount of dissolved gases because 1) The solubility of water will not change so significantly with temperature (we're not exceeding habitable temperatures, are we?) and 2) I would be very surprised if the water was completely saturated with CO2. There can be more DO than water in some cases (above 110% is unhealthy), so I do not believe that this would be an issue.

[ScienceOlympian]

Which part, in your opinion, is the most important? (Part One, Two, or Three?)

[Azismith]

Thank you!!
One thing though, even in the 'habitable' temperatures, I believe that the DO is affected quite a bit by temperature. I tried looking up 'temperature dissolved oxygen graph' on google pictures and was really surprised at how much temp. affected DO.
In addition, isn't it the organisms that 'respirate' (fish, etc.) that exhale the CO2, which then reacts with water to form carbonic acid?
Also, another question: In what sort of scenario can water be 110% saturated? I have also found that it can happen, but I don't quite understand how.