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Correct, your turn!

Which would you expect to have a higher salinity, surface waters at the equator or surface waters at 30 degrees north or south latitude? Why?

30 degrees north/south latitudes. At the the 30 degrees N/S latitudes (Tropics of Cancer/Capricorn), there is increased sunlight exposure due to Earth's precession. Because of this, we expect greater evaporation rates. When we evaporate more fresh water, the salts in the ocean remain leaving the water to be more saline. Conversely, at the equator, we see greater precipitation rates so that results in an addition of freshwater, making the salinity drop.

Correct, your turn.

It's been more than a week so I'm going to reboot it even though this isn't really active, but I like this event a lot.

Why is there more carbon dioxide at the bottom of the ocean than the top? (I'm looking for 3 different reasons)

Watergirl wrote:

Is it? (Click to Show Hidden Text)

1. One reason there is a higher concentration of CO2 on the ocean floor compared to the surface of the ocean is photosynthesis. At the surface of the ocean, there is enough sunlight for marine plants and plankton to perform photosynthesis, taking CO2 from the water to use it to produce their sugars. This would decrease the amount of CO2 levels at the surface. Most of the sunlight can't even reach the bottom of the ocean, so photosynthesis can't be performed here, which means there isn't a mechanism or a way to decrease the levels of CO2 here.
2. Another reason is the the rate of decomposition at the bottom of the ocean floor. At the bottom of the ocean floor, lots of the debris and dead matter from the surface sinks down until it reaches the bottom. Detritivores and decomposers come together to break down this dead matter into inorganic substances. They need to use respiration to supply the energy to break down the dead matter. Respiration would decrease the oxygen levels and increase the CO2 levels.
That's all I got so far :( But im going to guess the third one is probably related to CACO3??

You're really close and since you went into detail, I'm going to give it to you. The third one is that cold water absorbs CO2 and the "Conveyor Belt" brings it down from the high latitudes and the CO2 is at the bottom because that's where the deep ocean currents are.

Ohh, that makes so much sense. Warm water can't absorb as much gas as cold water can, so cold water will be able to absorb a higher concentration of CO2. Since cold water is denser than warm water, it will sink to the bottom, starting the thermohaline conveyor belt.

Watergirl wrote:Ohh, that makes so much sense. Warm water can't absorb as much gas as cold water can, so cold water will be able to absorb a higher concentration of CO2. Since cold water is denser than warm water, it will sink to the bottom, starting the thermohaline conveyor belt.

Feel free to ask a question, Watergirl!

How does the continental margin determine the distribution of abyssal plains?