So, for Naho
I found some interesting things. Most of them have to do with the cold waters.
Something called the Maelstrom:
http://www.toptenz.net/wp-content/uploads/2013/12/Maelstrom-ocean.jpg
Red Tides:
http://www.toptenz.net/wp-content/uploads/2013/12/red-tide-ocans.jpg
They are algae pretty dangerous.
Brinicles:
http://www.toptenz.net/wp-content/uploads/2013/12/brincile-oceans.jpg
When salty Ice melts a little, the water sinks. It eventually freezes again forming this. They are harmful, life gets either frozen or cut by the crystals.
Frost Flowers:
http://www.toptenz.net/wp-content/uploads/2013/12/frost-flowers.jpg
Requires no wind, and cold.
Two oceans meet:
http://www.toptenz.net/wp-content/uploads/2013/12/baltic-north-sea-ocean.jpg
The cold and sweet water from icebergs melts and meets the rest of the ocean, creating this phenomenon.
Well, creatures that have bioluminescense meet oxygen, you get this:
http://www.toptenz.net/wp-content/uploads/2013/12/bioluminescense.jpg
Brine pools, like a lake inside the ocean:
Form when a tectonic ■■■■■ exposes a salt deposit. The water becomes extremely salty, and dense. There is no oxygen there so normal sea life dies inside.
Better explained by this video.
It is all underwater. I suggest you watch in the highest definition you can muster. Since some things cannot be seen on the tiny screen.
Finally, not sure if you have heard of the Bay of Fundy. The tide rises to 48 ft, more than 12m, (this number varies, but I do not think it matters much considering the number itself is that large.)
There is a river that ends near the Bay, Let just say that when the tide is high, the ocean flows into the river, instead of the river flowing into the ocean.