seawater

This steady absorption of carbon makes seawater progressively more acidic over time.

Because radio and GPS signals cannot easily pass through seawater, sonobuoys are vital to modern naval detection systems and they are routinely used by navies during exercises and operations.

In addition, the shifting weight of seawater also applies pressure to the rocks below.

Some of these animals can photosynthesize like plants; some harvest algae and seawater to make calcium carbonate for their underwater castles; some produce their own light or glow in the dark.

Others rely on chemical or physical techniques, including systems that directly remove carbon dioxide from seawater.