Why Are Oceans Salty?

Jeremy Bishop, Unsplash
Jeremy Bishop, Unsplash

There are certain facts about the oceans of the world that everyone knows. Anyone who's been knocked over by a wave at the beach knows what the ocean tastes like: salt. This is true whether you swallow a mouthful of seawater off the coast of Queensland or the Jersey Shore. The ocean's salinity is one of the defining features separating it from freshwater bodies like lakes and rivers. But what is it exactly that makes the ocean saltier than a bucket of boardwalk fries?

To understand why oceans are salty, you need to know what salt is and where it comes from. Chemically speaking, a salt is a compound composed of two groups of oppositely charged ions. When an atom contains more protons than electrons, it becomes a positively charged ion. Atoms with more electrons than protons are negative ions, or anions. Atoms with opposite charges attract one another to form chemical compounds.

The chemical composition of table salt is sodium chloride, with sodium being the positive ion and chloride being the negative one. Sodium and chloride also make up most salt in the ocean, but they're not the only minerals contributing to the sea's salinity. "Salt in the ocean isn't just sodium and chloride—it's a mixture of a bunch of ions like magnesium and calcium as well, most of which start out as rocks on land," Dr. Morgan Raven, an organic geochemist and geobiologist and assistant professor of earth science at the University of California Santa Barbara, tells Mental Floss.

Most of the ocean's salt comes from rocks. The dissolved carbon dioxide in rainwater makes it slightly acidic, and when rain falls, it erodes rocks on land. Minerals from these rocks leach into rivers and streams, which then carry the salts into the ocean. About 85 percent of the ocean's ions are sodium and chloride, while magnesium and sulfate make up around 10 percent.

Not all salt that ends up in the ocean stays there. Salt is a life-sustaining substance, and a lot of the ocean's salt is consumed by animals. But thanks to a steady supply of runoff from the surface, salinity levels are able to remain fairly constant. The ocean can count on one more source for its salt content: hydrothermal fluids. Deep sea vents are heated by magma from beneath the Earth's crust, and they get hot enough to cause chemical reactions between seawater and minerals from the surrounding rocks. Underwater volcanoes are another example of hot rocks and water adding more salt to the sea.

Every part of the ocean is salty, but just how salty varies depending on where in the world you are. "One of the reasons that oceanographers love to use salinity to study the ocean is that there are only a few ways that it can change, and they all happen at either the ocean surface or the sea floor," Raven says. "For example, surface water in the Mediterranean Sea is saltier than the equatorial Pacific because enhanced evaporation in a dry climate concentrates salt, while rain at the Equator dilutes salt."

Salinity isn't inherent to seawater. It's the result of a steady give-and-take of ions entering and leaving the ocean. This same process occurs in other bodies of water, but the ion intake isn't always high enough to make the water truly salty. That's why the rivers and streams that deliver salt to the ocean are still considered freshwater: Dilution from the rain tends to offset whatever ions they carry. The ocean, meanwhile, acts as the dumping ground for the world's salt, and no amount of dilution can change that.

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10 Reusable Gifts for Your Eco-Friendliest Friend

Disposable tea bags can't compete with this pla-tea-pus and his friends.
Disposable tea bags can't compete with this pla-tea-pus and his friends.

This article contains affiliate links to products selected by our editors. Mental Floss may receive a commission for purchases made through these links.

By this point, your eco-friendly pal probably has a reusable water bottle that accompanies them everywhere and some sturdy grocery totes that keep their plastic-bag count below par. Here are 10 other sustainable gift ideas that’ll help them in their conservation efforts.

1. Reusable Produce Bags; $13

No more staticky plastic bags.Naturally Sensible/Amazon

The complimentary plastic produce bags in grocery stores aren’t great, but neither is having all your spherical fruits and vegetables roll pell-mell down the checkout conveyor belt. Enter the perfect alternative: mesh bags that are nylon, lightweight, and even machine-washable.

Buy it: Amazon

2. Animal Tea Infusers; $16

Nothing like afternoon tea with your tiny animal friends.DecorChic/Amazon

Saying goodbye to disposable tea bags calls for a quality tea diffuser, and there’s really no reason why it shouldn’t be shaped like an adorable animal. This “ParTEA Pack” includes a hippo, platypus, otter, cat, and owl, which can all hang over the edge of a glass or mug. (In other words, you won’t have to fish them out with your fingers or dirty a spoon when your loose leaf is done steeping.)

Buy it: Amazon

3. Rocketbook Smart Notebook; $25

Typing your notes on a tablet or laptop might save trees, but it doesn’t quite capture the feeling of writing on paper with a regular pen. The Rocketbook, on the other hand, does. After you’re finished filling a page with sketches, musings, or whatever else, you scan it into the Rocketbook app with your smartphone, wipe it clean with the microfiber cloth, and start again. This one also comes with a compatible pen, but any PILOT FriXion pens will do.

Buy it: Amazon

4. Food Huggers; $13

"I'm a hugger!"Food Huggers/Amazon

It’s hard to compete with the convenience of plastic wrap or tin foil when it comes to covering the exposed end of a piece of produce or an open tin can—and keeping those leftovers in food storage containers can take up valuable space in the fridge. This set of five silicone Food Huggers stretch to fit over a wide range of circular goods, from a lidless jar to half a lemon.

Buy it: Amazon

5. Swiffer Mop Pads; $15

For floors that'll shine like the top of the Chrysler Building.Turbo Microfiber/Amazon

Swiffers may be much less unwieldy than regular mops, but the disposable pads present a problem to anyone who likes to keep their trash output to a minimum. These machine-washable pads fasten to the bottom of any Swiffer WetJet, and the thick microfiber will trap dirt and dust instead of pushing it into corners. Each pad lasts for at least 100 uses, so you’d be saving your eco-friendly friend quite a bit of money, too.

Buy it: Amazon

6. SodaStream for Sparkling Water; $69

A fondness for fizzy over flat water doesn’t have to mean buying it bottled. Not only does the SodaStream let you make seltzer at home, but it’s also small enough that it won’t take up too much precious counter space. SodaStream also sells flavor drops to give your home-brewed beverage even more flair—this pack from Amazon ($25) includes mango, orange, raspberry, lemon, and lime.

Buy it: Amazon

7. Washable Lint Roller; $13

Roller dirty.iLifeTech/Amazon

There’s a good chance that anyone with a pet (or just an intense dislike for lint) has lint-rolled their way through countless sticky sheets. iLifeTech’s reusable roller boasts “the power of glue,” which doesn’t wear off even after you’ve washed it. Each one also comes with a 3-inch travel-sized version, so you can stay fuzz-free on the go.

Buy it: Amazon

8. Countertop Compost Bin; $23

Like a tiny Tin Man for your table.Epica/Amazon

Even if you keep a compost pile in your own backyard, it doesn’t make sense to dash outside every time you need to dump a food scrap. A countertop compost bin can come in handy, especially if it kills odors and blends in with your decor. This 1.3-gallon pail does both. It’s made of stainless steel—which matches just about everything—and contains an activated-charcoal filter that prevents rancid peels and juices from stinking up your kitchen.

Buy it: Amazon

9. Fabric-Softening Dryer Balls; $17

Also great for learning how to juggle without breaking anything.Smart Sheep

Nobody likes starchy, scratchy clothes, but some people might like blowing through bottles of fabric softener and boxes of dryer sheets even less. Smart Sheep is here to offer a solution: wool dryer balls. Not only do they last for more than 1000 loads, they also dry your laundry faster. And since they don’t contain any chemicals, fragrances, or synthetic materials, they’re a doubly great option for people with allergies and/or sensitive skin.

Buy it: Amazon

10. Rechargeable Batteries; $40

Say goodbye to loose batteries in your junk drawer.eneloop/Amazon

While plenty of devices are rechargeable themselves, others still require batteries to buzz, whir, and change the TV channel—so it’s good to have some rechargeable batteries on hand. In addition to AA batteries, AAA batteries, and a charger, this case from Panasonic comes with tiny canisters that function as C and D batteries when you slip the smaller batteries into them.

Buy it: Amazon

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Can Presidents Pardon Themselves?

Pete Souza, The White House // Public Domain, Wikimedia Commons
Pete Souza, The White House // Public Domain, Wikimedia Commons

Whether or not there are limits to a president's pardoning powers is a question that has been debated since the writing of the Constitution. And in more recent decades, the debate has centered around one specific question: Can presidents pardon themselves?

Are there limits to a President's pardon power?

Presidential pardons are laid out in Article II, Section 2 of the Constitution, which says the president “shall have Power to grant Reprieves and Pardons for Offenses against the United States, except in Cases of Impeachment.”

That sentence alone cites the first two limitations to a president's pardon powers. "Offenses against the United States" is taken to mean that the president can only pardon federal crimes, not state crimes. Also, impeachment convictions are off-limits [PDF].

Meanwhile, in 1862, the Supreme Court declared that the president's pardon power "extends to every offence known to the law, and may be exercised at any time after its commission, either before legal proceedings are taken, or during their pendency, or after conviction and judgment." That means that being indicted and/or convicted of a crime isn't necessary to be pardoned—just that the crime itself must have already occurred [PDF].

A Constitutional History

According to a 1977 article in the William & Mary Law Review [PDF], going into the 1787 Constitutional Convention, there were no plans to include pardon power in the Constitution. It was politicians Charles Pinckney, John Rutledge, and Alexander Hamilton who fought for it.

It was during this same time that the question of whether there should be presidential pardon limits first arose. One person wanted to require the consent of the Senate as part of the pardoning process; he was voted down. Someone else wanted to add in “after conviction,” but was convinced that sometimes pardons before conviction might be desirable, so he withdrew his motion.

The biggest debate, however, was over the power to pardon treason.

In one pamphlet, George Mason—a politician and one of three U.S. Constitutional Convention delegates who refused to sign the Constitution because they considered it flawedcomplained that “The President of the United States has the unrestrained power of granting pardon for treason, which may be sometimes exerted to screen from punishment those who he had secretly instigated to commit the crime, and thereby prevent a discovery of his own guilt.”

Months later, when Virginia was considering ratifying the Constitution, George Mason was at it again, worrying that “The president ought not to have the power of pardoning, because he may frequently pardon crimes which were advised by himself ... If he has the power of granting pardons before indictment, or conviction, may he not stop inquiry and prevent detection?”

James Madison responded that there was a way to stop such abuses: impeachment. According to an account of the debate, Madison said that “If the president be connected in any suspicious manner with any persons, and there be grounds to believe he will shelter himself: The House of Representatives can impeach him; They can remove him if found guilty; They can suspend him when suspected, and the power will devolve on the vice president. Should he be suspected also, he may likewise be suspended till he be impeached and removed, and the legislature may make a temporary appointment. This is a great security.”

Ultimately, the Constitution—complete with broad pardoning powers—would become the law of the land.

What are the arguments against presidential self-pardoning?

In a 2019 paper, Dr. Michael J. Conklin of Angelo State University summarized the arguments on the pro- and anti- self-pardons debate. Arguments from the anti-self-pardon side include:

  • The fact that a pardon is inherently bilateral, so a unilateral pardon makes no sense. In 2018, George W. Bush’s chief ethics lawyer Richard Painter told CNBC: “I do not know of an instance in human history in which a king has pardoned himself. The pope does confession to another priest. A pardon is, by its very nature, when one person pardons another.”
  • That the Constitution is generally against self-dealing, and a self-pardon definitely fits that.
  • That if presidents can pardon themselves, there is little recourse remaining. A popular president seeking re-election is unlikely to be the one using the self-pardoning power. It’s more likely to come from a president like Richard Nixon, who has few to no allies left, or a president at the end of their term. In the words of legal scholar Brian Kalt, “the only president who would pardon himself is one with nothing to lose; the political check is thus rendered irrelevant.” This is in contrast to Gerald Ford’s pardon of Nixon, which “was a considered policy judgment just like any other conventional pardon, and not a go-for-broke, corrupt self-pardon.” Unlike a Nixon self-pardon, Ford faced the people to pass judgment in the next election [PDF].

What are the arguments for presidential self-pardoning?

On the pro-self-pardoning side, Conklin lists the following arguments:

  • The self-dealing issue doesn’t make sense, because a president can still pardon co-conspirators and prevent any investigation into presidential wrongdoing—which on the surface would seem as self-dealing as a self-pardon.
  • Supreme Court cases tend to support presidential pardoning power. In Schick v. Reed, the court held “that the pardoning power is an enumerated power of the Constitution, and that its limitations, if any, must be found in the Constitution itself.” (Anti-self-pardoning advocates point out that the case also states that “the pardoning power was intended to include the power to commute sentences on conditions which do not, in themselves, offend the Constitution” [PDF]).
  • It would mean the president could pardon every person in America—except one.

Both sides claim the point that the Constitution doesn’t say one way or the other. Kalt argues that this is because the Founders seemed to have never even considered that people might think a self-pardon was possible while others, like lawyer Robert Nida, argue that the restrictions noted in the Constitution are the only restrictions.

The closest the government has ever gotten to officially answering the question is in a 1974 memo from the Office of Legal Counsel, which said, “Under the fundamental rule that no one may be a judge in his own case, the President cannot pardon himself.” Still, not everyone agrees.

So can a president pardon himself or what?

So can a president pardon themselves? The answer is unclear. Because it has never been tried (yet), legal opinion is all over the place. Conklin’s explanation of the background was a prelude to the discussion of a survey he sent to 29 law schools asking faculty if they felt it was constitutional for a President to pardon themselves. The average response came out as "probably not." Though there is another possibility ...

In the same memorandum that said no one can be the judge in their own case, the Office of Legal Counsel suggested an alternative. The 25th Amendment allows the president to convey in writing an inability to perform the duties of the presidency, and those “powers and duties shall be discharged by the Vice President as Acting President.” Then, when the inability is lifted, the president returns to power.

This has happened a few times in U.S. history. In 2007, for instance, George W. Bush was undergoing a colonoscopy and so, for two hours, Dick Cheney was Acting President. But in those two hours, could Cheney have gone on a pardoning spree? The Department of Justice wrote, “If under the Twenty-Fifth Amendment the President declared that he was temporarily unable to perform the duties of the office, the Vice President would become Acting President and as such could pardon the President. Thereafter, the President could either resign or resume the duties of his office.”

No matter what, if a president tried any of this the legal challenges would be extreme—so the most accurate answer to the question of self-pardon is probably the one that came from Stanford University’s John Kaplan, who noted in 1974, "Anybody who tells you that he can think of what the answer is, just doesn’t know what he’s talking about."

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.