Howdy cohost. Saw folks out there posting science facts and decided to throw my hat into the ring.

Today's marine science fact: the global ocean conveyor belt!
You may know that all the oceans are connected to each other, but did you know that there's a 1500 year long water circulation cycle happening between them? It's all driven by the formation of deep ocean water in the Arctic Ocean.
When ocean water enters the Arctic, it cools down and starts to freeze. This does two things. One, the water that freezes solid gets pulled out of the liquid water at the surface. This makes the remaining liquid water extra salty, as the ice leaves but the salt it used to carry stays behind. Two, because the water is extra salty, its freezing point gets even lower. So now you have really cold, really salty water. And this cold salty surface water is denser and heavier than the regular seawater it's on top of. And if you know anything about density, you'll know that this dense water is gonna sink all the way to the bottom.
That formation of new deep-ocean water in the Arctic starts this whole global conveyor belt. That deep water takes whatever was at the surface when it formed (oxygen, organic matter from living things) and takes it all the way to the bottom. And all that stuff slowly makes its way through the oceans. You can actually track the movement of the water by comparing the oxygen, CO2, and nutrient levels in water from the North Atlantic, to water in the North Pacific. North Atlantic water is super well oxygenated and full of organic matter. Whereas North Pacific water has had ~1500 years for everything in it to get consumed and broken down by deep sea bacteria. It is full of CO2 and nutrients, and very oxygen-depleted.
This CO2 and nutrient heavy bottom water eventually comes back up, where it becomes really, really important for the oceanic food cycle. But that will be a topic for another time.
Happy Monday, and I'll sea you all next week!
For the image source, and more detail: https://www.e-education.psu.edu/earth103/node/686

