The world’s oceans cover about 71% of the Earth’s surface, totaling approximately 361 million square kilometers (139 million square miles), but only 3 percent of that is freshwater and 1.3 percent is used for drinking.
It’s fascinating how aquatic animals survive in salty water, unlike us. How does seawater become salty? How can it be balanced?
Here’s a detailed explanation of why seawater is salty:
Over Earth’s time, minerals and salts have been disintegrated from rocks ashore. These minerals are conveyed by waterways and streams into the sea. Water likewise gets broken down minerals as it streams over the land and in the long run arrives at the sea. Over millions of years, these disintegrated minerals, essentially sodium chloride (table salt), yet magnesium, calcium, potassium, and others, aggregate in the seas. This cycle is known as weathering and erosion.
The salts enter the sea through different pathways, including streams, groundwater release, and volcanic movement (where minerals are delivered during submerged volcanic eruptions).
Salts continuously enter the ocean and are removed through processes like mineral precipitation, chemical reactions, and the formation of evaporite deposits. However, the sea remains salty because the rate of salt input exceeds the rate of removal.
Aquatic animals have adapted to the salty conditions of seawater over millions of years and efficiently regulate the salt concentration within their bodies through osmoregulation,( Osmoregulation is how organisms regulate water and solute levels to maintain internal stability despite external changes. This process is crucial for cell and tissue function, ensuring optimal physiological processes.).
Aquatic species fish and sea turtles, possess the remarkable ability to drink seawater and excrete excess salts through specialized glands. Meanwhile, most marine invertebrates have well-developed internal mechanisms to effectively regulate their salt levels.
So, these minerals and ions are continuously added to the sea, and aquatic animals have adapted to them over time.