Water science news, explainers, and statistics covering freshwater, hydrology, lakes, rivers, groundwater, ice, and Earth’s connected water systems.
An anchialine pool is a landlocked coastal pond with a hidden connection to the sea. Fresh groundwater enters from the land while seawater moves through porous rock or cave passages below ground. The result is usually a small body of brackish water whose level may rise and fall with distant ocean tides, even though no…
More
Seawater becomes denser as it cools or gains dissolved salt. It becomes less dense as it warms or is diluted by fresh water. Pressure compresses water slightly at depth, so an exact density calculation includes temperature, salinity and pressure together. The differences are modest, but gravity acts on entire water masses. Dense water tends to…
Ocean stratification is the arrangement of seawater into layers with different densities. Lighter water remains above denser water, reducing vertical mixing between the surface and the deep ocean. Temperature usually creates the strongest contrast across much of the planet, while salinity becomes decisive in rainy, icy or river-influenced regions. Layering is a normal feature of…
The ocean mixed layer is the well-stirred water nearest the surface. Wind, waves and changes in surface temperature continually move water through it, leaving temperature and density relatively uniform from the top down to a measurable boundary called the mixed-layer depth. This upper layer is where the sea meets the atmosphere. Heat enters and leaves…
