The Science Behind Why You Can’t Drink Ocean Water

While the ocean is one of the most vital elements of the earth’s ecosystem, it’s also one of the most dangerous. We’ve all seen or heard about the devastation it can wreak when hurricanes or tsunamis hit. 

Even on its best day, it still contains something else that’s quite dangerous for humans: saltwater. It’s perfectly fine to swim in saltwater and enjoy its relaxing waves. But, we must be careful never to drink ocean water for several reasons. 

The Dangers of Drinking Ocean Water

Hand in the ocean
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The main reason the answer to, ”Can you drink ocean water?” is a resounding no is because of its salt content. There are other concerns relating to dehydration and the ingestion of bacteria, as well. 

Many of us enjoy drinking natural spring water. In this article, we outline the difference between spring water and purified water. While spring water is perfectly drinkable (assuming it’s been tested), ocean water is fundamentally different due to its high salinity levels. 

On average, ocean water contains about 3.5% salt, mainly in the form of sodium chloride. That equals about 35 grams of salt per liter. As a point of comparison, our blood cells and fluids only have a salinity level of about 0.9%. You can see how the ingestion of ocean water could throw our system out of balance. 

One thing to keep an eye on as you peruse the weather news is saltwater intrusion. This is the movement of saline water into freshwater aquifers. As you can imagine, the more the ocean encroaches upon freshwater supplies, the less viable those drinking solutions will become. 

The Dangers of Dehydration

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Interestingly, the main correlation between ocean water and the human body is osmosis. Osmosis plays an important role in our systems; it regulates the flow of liquids, dissolved solids, and gasses through the semipermeable membrane of cells that decide which substances are allowed to pass in and out of each cell. 

When we ingest saltwater, we add a high concentration of salt into our digestive tract. This causes water to move out of our cells and into our digestive system while there’s a major imbalance in our salt levels. This causes cellular dehydration. 

When this happens, the body will try to rid itself of the excess salt, causing the kidneys to work overtime to filter out the sodium. However, kidneys can only output urine that is less salty than seawater. 

To account for that, the kidneys end up taking more water away from the body than was consumed in order to increase urine production. Consequently, instead of hydrating the system, salt water has just depleted it. 

Although a dehydration headache may not be as difficult to endure as a gastrointestinal problem, it’s yet another reason to avoid drinking salt water. 

The Dangers of Bacteria

Garbage in the ocean
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Ocean water is an oasis for countless microorganisms, including bacteria, parasites, and viruses. While many of them are harmless, especially when we interact with them in very small doses, they can pose significant health risks if they’re ingested. 

Drinking contaminated seawater may introduce harmful pathogens into the body, leading to various illnesses and infections. One of the most dangerous groups of ocean bacteria that live in seawater are called Vibrio. 

These bacteria can cause severe gastrointestinal issues including diarrhea, vomiting, and abdominal pain. In severe cases, they can even lead to sepsis (blood poisoning), which can be fatal. 

Have you ever heard of red tides? When they’re present, it’s not wise to swim in the water, let alone ingest it. Red tides contain algal blooms that produce harmful toxins. 

The toxins produced by these blooms can cause an even wider variety of health problems, including gastrointestinal problems, respiratory distress, and neurological symptoms – all of which can be life threatening. 

What Else Can You Drink?

Rainwater caught in a barrel
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If you’ve ever watched the TV series, Lost, you might’ve found it fascinating to see how they tried to survive. Most of them knew not to drink salt water. So, they started collecting rainwater in tarps. Of course, if the tarps were dirty or the water stagnated, that posed its own set of bacterial problems. 

Still, drinking rain water is the safer bet. In a survival situation, if there’s a way to collect dew, that’s another alternative. Some plants and fruits that grow in coastal areas can also offer a water supply, albeit small. A desalination kit or solar still would offer safer options for hydration. 

It’s interesting to think the ocean covers more of the earth than land, and we can’t use it as a source of hydration. We hope this helps you see why drinking ocean water can never be an option. Not only will it not quench your thirst, it may also bring on a host of residual effects. 

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