Underwater lakes with their own shorelines and waves exist on the ocean floor.

Brine pools are found in places like the Gulf of Mexico and the Red Sea. One famous pool is called the Jacuzzi of Despair. It was found in 2014 about 1,000 meters underwater. The water in this pool is 19 degrees Celsius, which is much warmer than the 4-degree water around it.The water in these pools is four to five times saltier than the ocean. This high salt level creates a visible border called a halocline. The brine is so thick and heavy that deep-sea submarines can float on top of it like a boat on a pond. Most sea animals die if they swim inside because the water has no oxygen and too much salt.Despite the danger, life still grows around the edges. Giant mussels live on the shoreline. They have special bacteria that turn methane gas from the pool into food. This process is called chemosynthesis. It allows animals to survive in the dark without any sunlight.