Why Can't We Drink Seawater?

Introduction

One color dominates our image of our planet when we look at it from the expanse of space: blue. It is understandable why Earth is frequently referred to as the "Blue Planet" given that water covers over 75 percent of its surface. Unbelievably, 96.5 percent of this water is confined in the oceans and is unfit for human consumption. Why then is ocean water salty and unsafe to drink? In this essay, we'll examine the intriguing causes of seawater's salinity and how they affect our attempts to quench our thirst with it.

The Two Principal Causes of Salinity in Oceans

Two main variables, geological processes in the Earth's crust and runoff water from the land, are principally responsible for the salinity of ocean water.

1. Water Runoff from the Land

Rainwater has a pH level between five and five and a half, making it mildly acidic as it falls from the sky. The pH of battery acid is below zero, making it more acidic than pure water, which has a neutral pH of seven. Rainwater has the ability to dissolve rocks when it touches the surface of the Earth, releasing ions like sodium and chloride. These ions eventually end up in streams and rivers, which then empty into the oceans. Some of these ions are removed by living things, but many of them stay in the water, gradually increasing their concentration.

2. Hydrothermal Vents: Geological Processes

Geological processes that take place below the ocean's surface greatly contribute to the salinity of seawater. Key participants in this process are the hydrothermal vents on the ocean floor. The magma from the Earth's core heats the water as it seeps through cracks in the ocean floor, causing a chemical process that releases oxygen from the seawater. Water can also pick up metals like iron and zinc through this mechanism. The metallic water is returned to the ocean by these hydrothermal vents, adding to the salt content. Minerals such as salt and other elements are immediately thrown into the waters during underwater volcanic eruptions. These salts build up on the ocean floor over time and eventually create domes.

factors that affect salinity

Ocean water salinity is influenced by a number of variables, such as evaporation, air temperature, and precipitation. The oceans and seas in between, on the other hand, typically have higher salinities than regions close to the equator and at the poles. According to scientists, about three and a half percent of the weight of the ocean's water is made up of dissolved salts.

The Gathering of Salt Throughout History

We must examine the geological history of our globe to comprehend why seawater is salty. According to researchers, prehistoric waters were less salinized than modern ones. Rainfall destroyed land-based rocks throughout time, carrying enormous amounts of salt into the oceans. Over 3.8 billion years have passed since the beginning of this process, and every year, about 4 billion tons of dissolved salts enter the oceans on Earth. The steady salinity levels we see today have been maintained by this equilibrium between salt input and discharge.

Why Seawater Isn't Safe to Drink

Although we already get enough salt in our diets, our systems can only take so much salt at once. To preserve good heart health, the World Health Organization advises people to limit their daily salt intake to no more than one teaspoon per person. Salted beef and pork were a mainstay of seafarers' diets centuries ago because salt preserved meat throughout protracted sea voyages. Seawater contains significantly more salt than what our bodies can metabolize, though.

We also drink liquids to slake our thirst when we include salt in our diet. This keeps the level of salt in our bodies in balance. But when we consume seawater, we unintentionally consume more salt without giving our bodies enough water to counteract it. The function of our kidneys is to remove extra salt from our bloodstream, but doing so requires water. Our bodies release more water than we take in when the salt concentration is too high, which causes dehydration.

Whales, seals, and birds like seagulls that live in the ocean have developed effective ways to drink seawater. They have specific glands and organs that allow them to successfully eliminate extra salt. The camel, which has adapted to its desert habitat, is the only land animal known to be able to drink seawater.

Desalinization: A Difficult Problem

Desalination, a procedure that takes the salt out of seawater, is necessary to make seawater drinkable for people. Although this technology is available, there are considerable obstacles in the way of its general use. Less than 0.5 percent of the world's drinking water is currently desalinated seawater. The main difficulty is the enormous energy expense, which is roughly ten times more expensive than other water production techniques. For large desalination facilities to function effectively, they frequently need their own power plants.

Reverse osmosis, which involves applying pressure to saltwater to force it through tiny filters with holes smaller than a human hair, is the primary method used by desalination plants. While this technology effectively removes salt, it is ineffective for mass water purification because it produces twice as much salty water for every quarter gallon of fresh water generated.

The Effect on the Environment

It would be expensive to remove all salt from Earth's oceans in order to produce an infinite supply of drinkable water. Numerous marine organisms, such as plankton, which forms the basis of marine ecosystems, are accustomed to saltwater settings and would find it difficult to adjust to abrupt changes in salinity. The Arctic ice cap would also recede by four inches as a result of the change from saltwater to freshwater, possibly resulting in enormous tidal waves.

Conclusion

In conclusion, the intricate interaction of geological processes, historical salt accumulation, and the restrictions of our own bodies is the root cause of the riddle of why we can't drink seawater. Although desalinization has the potential to quench our expanding desire for freshwater, its high energy costs and negative environmental effects make it a subpar answer. We must continue to be aware of the delicate balance that saltwater ecosystems and our planet's natural processes maintain as we look for ways to guarantee a sustainable supply of safe drinking water. We may not be able to drink seawater anytime soon, but comprehending the causes of its salinity is an important first step in addressing the world's growing need for freshwater resources.