Brine Pools

 

Today we explored water density stratification in the ocean and focused specifically on brine pools.

Different areas of the ocean have different concentrations of dissolved salt or temperature, which results in density differences. When it rains for example, a layer of fresh water accumulates on the surface until wave action eventually helps mix it with deeper water. In some deep ocean areas there exist pools and lakes of extreme salinity and density. These are known as brine pools or cold seeps. These areas have such a high density in comparison to the surrounding water that it pools in underwater basins creating the effect of a pool or lake or river, complete with waves or “water falls”. 

 
 


To demonstrate this density layering effect, we used different-density fluids: corn-syrup, dish soap, water, vegetable oil, and alcohol. The students measured out equal volumes and then noted the weight of each liquid. From this they hypothesized how each fluid would layer based on its density. To differentiate between different clear layers, food coloring was used, which resulted in a very pretty column of stratified liquids which the students had a lot of fun creating.

 

Videos used in today's workshop

Brine pools, on one hand, provide the basis for life through chemosynthesis for creatures living near them on the bottom of the ocean. On the other hand, the fluid they contain is extremely toxic to many forms of sea life. Here we see creatures that have ventured inside the dangerous interior of the brine pool and failed to return.
 

A cutthroat eel ventures too close to a deep-sea brine lake.