The ocean. It’s a big salty blue thing. But have you ever wondered how it got so salty in the first place? Don’t worry, because we’re going to do a deep dive.
Here are five things to know:
- Let’s start at the top. When it rains, carbon dioxide in the air gets dissolved, making the raindrops a little bit acidic. And, when it reaches rocks on land, it weathers and erodes them, releasing salt minerals that flow into the rivers and eventually into the sea. It’s estimated that globally rivers carry around 4 billion tons of dissolved salts into the ocean each year.
- Salt also comes from cracks in the seafloor, hydrothermal vents where the magma from the Earth’s core hyper-heats the seawater carrying minerals. There are also underwater volcanic eruptions that do the same and massive salt deposits known as salt domes — it’s the dissolved salts that create about 3.5% of the weight of seawater.
- The minerals deposited into the sea have built up over millions of years — becoming more and more concentrated. Scientists estimate that there’s so much salt in all our oceans that if we removed it and spread it over the Earth’s surface evenly, it would make a layer around 500 feet thick.
- The level of salinity of the oceans is hugely important because the saltier sea is actually heavy and can affect ocean current movement, which is how heat is transported around the globe, helping to regulate the Earth’s climate.
- Even more important is the salinity level’s impact on marine life. Too much salt can be disastrous. There’s a reason why one of the saltiest seas on the planet is called “The Dead Sea.”
So now you know how our seas became so salty and why it’s imperative to protect and take care of these vast blue watery reserves as they surely hold the future of our planet and all living things within their briny deep.