# Relationship between carbon dioxide and dissolved oxygen

This exchange is helped by the mixing of the surface by wind and waves. Dissolved oxygen and carbon dioxide are vital for marine life. conducted in the Ji-Paraná River, quantifies the CO2 flux in the water-air .. The relationship between dissolved oxygen and discharge (Fig. Dissolved oxygen and carbon dioxide undergo daily cycles in the water hyacinth top to bottom differential in the concentrations of the dissolved gases.

Now that's kind of funny.

It might strike you as kind of a funny thing. Because look, these partial pressures are basically the same. I mean, not even basically, they're exactly the same. There's no difference in the partial pressure. And yet the concentrations are different. So if you keep the P the same, the only way to make for different concentrations is if you have a different constant.

So let me actually move on and figure out what the constant is.

## Oxygen and Carbon Dioxide

So what do you think the constant on this side would be, higher or lower? Let's see if we can figure it out together. The K sub H on this side is going to be lower. It's going to be lower. It's 29 liters times atmosphere divided by moles.

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So it's a much lower number. And I don't want you to get so distracted by this bit. This is kind of irrelevant to what we're talking about. It's just the units, and we can change the units to whatever we want. But it's this part-- it's the fact that the number itself on the carbon dioxide side is lower.

Now let's think back to this idea of Henry's law.

### Oxygen and Carbon Dioxide | Teaching Great Lakes Science

Henry's law told us that the partial pressure, this number, tells you about what's going to be going into the water, and that the K sub H tells you about what's going out of the water. And so if what's going in on both sides is equivalent, then really the difference is going to be what's the leaving. And on this side, on the first side of our experiment, we had lots of oxygens leaving this water.

They didn't like being in water.

They were leaving readily. And so you didn't see that, but they were actually constantly leaving. And on the carbon dioxide side, you had maybe a little bit of leaving, but not very much. The carbon dioxide was actually very comfortable with the water. In fact, to see that as a chemical formula, you might recall this. Well, think about that. If it's a binding to the water then it's not going to want to leave.

It's pretty comfortable being in the water. And so the moment that carbon dioxide goes into water, it does something like this. It binds to the water. It turns into bicarbonate and protons. And so it's a very comfortable being in water, and that's why it's not leaving. In fact, I can take this one step further and even compare the two. I could say, well, divided by 29 equals about So that's another way of saying that carbon dioxide is 26 times more soluble than oxygen.

I'll put that in parentheses-- than oxygen. And I should make sure I make it very clear.

### O2 and CO2 solubility (video) | Gas exchange | Khan Academy

This is at 25 degrees Celsius, and this is in water. Now, you might say, well, that's fine for 25 degrees Celsius. But what about body temperature? What's happening in our actual body? What's happening in our lungs? So in our lungs, we have 37 degrees Celsius. And instead of water-- actually, I shouldn't be writing water-- instead of water, it's blood, which is slightly different than water.

The consistency is different. And so these K sub H values are actually temperature dependent. And they're going to change as you increase the temperature. So at this new temperature, it turns out that carbon dioxide is about 22 times more soluble than oxygen.

So it's still pretty impressive. Underwater plants and algae also contribute oxygen during the process of photosynthesis. Photosynthesis is the process green plants use to make sugars, part of the food they need to grow. Fishy Business Dissolved oxygen in the Great Lakes is affected by weather and temperature. Cold water holds more oxygen than warm water. Because trout or salmon need a high level of oxygen to survive, they live in fast-moving, cold streams and rivers, or in deep, cold lakes.

Warm-water fish such as bluegills, crappie, perch, walleye, catfish and carp can tolerate lower levels of dissolved oxygen in the water. It is important to monitor DO, since it can be used as an indicator of water quality. Anoxia occurs when oxygen levels are low and often results when dry, hot weather causes water to warm and evaporation increases. Anoxia can also result from the runoff of fertilizer and organic wastes including pet droppings from streets, lawns and farms.

When excess nutrients, including nitrogen and phosphorus, enter the water, algae grows quickly—creating an algae bloom. Algae produce oxygen during the day through photosynthesis but also quickly consume oxygen at night during respiration. Bacteria decompose the algae after the bloom dies, using a significant amount of oxygen in the process.

The result is a lack of available oxygen for other plants and animals that need it, possibly causing a fish kill. It can dissolve in water times more easily than oxygen. Aquatic plants depend on carbon dioxide for life and growth, just as fish depend on oxygen. Plants use carbon dioxide during the process of photosynthesis.

Sometimes carbon dioxide levels in water become too high.