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How Can Bodies of Water Be Different Colors?

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When I saw the Caribbean Sea in person for the first time, my eyes metaphorically popped out of my head. As a kid who grew up in South Jersey, I was used to the dirty, almost brown, kinda-sorta blue color of the coastal Atlantic Ocean. But this was different. Staring at that bright, vibrant, and seemingly crystal-clear water, I had many questions. Where did that color come from? And why can I see my feet here, but not at home? Is the Caribbean water cleaner? Is the sun stronger down south? And how come it’s green-blue near the shore, yet navy blue a mile off shore?

Having traveled quite a bit since, I’ve heard all kinds of explanations from common folks, some chalking color differences up to pollution and others to salinity. While I’m certain that many factors, including those two, play some small role, the biggest influencers are the floor, depth, and microorganisms of the body of water.  

First off, let’s tackle why water, in most cases, appears blue to begin with.

Shedding a little light

If you’ve ever taken a cruise, you know that the farther offshore you sail, the deeper and bolder the blue becomes (navy blue). That’s because there are no reflections off the sea floor in very deep water, meaning that a majority of the sun’s rays are absorbed by the water itself. Water molecules, by nature, absorb reds, greens, oranges, and yellows, but spit out blue.

“When sunlight hits the ocean, some of the light is reflected back directly but most of it penetrates the ocean surface and interacts with the water molecules that it encounters,” explains NASA’s Oceanography Division. “The red, orange, yellow, and green wavelengths of light are absorbed so that the remaining light we see is composed of the shorter wavelength blues and violets.”

Sanding Off

As the water depth decreases and the light is able to penetrate all the way to the bottom, the makeup of the floor becomes a factor in determining water color. For example, the coarse Caribbean coral is going to reflect light differently than the fine sand found in the Northeast. These differences in absorption and reflection affect visibility as well as color.

Whatever light is not reflected back from the top layer of water or the bottom of the sea floor is absorbed by something in the water. As we saw above, lots of light is consumed by the water molecules themselves, but microorganisms living in the water also “eat” their fair share. The final major players in determining color are the particles and organisms found and suspended in the water. Phytoplankton, for example, harbors chlorophyll that absorbs red and blue light and reflects green. If a high concentration exists in one area, the water will take on a green hue. The more there are, the greener the water will appear.

Those three factors—depth, floor makeup, and life (plus intangibles, like pollution, as mentioned above)—will interact to produce whatever color we happen to see. The same principles apply to other bodies of water, like lakes, craters, and rivers. It’s all about what’s in and under the water.

And, despite our focus on the oceans, it’s not all about being green, blue, or brown. Check out these uniquely colored tourist attractions found in different parts of the world as examples. If you thought the greenish-blue of the Caribbean was impressive, the red and black volcanic lakes should knock your socks off.

Laguna Colorada, Bolivia

Courtesy of Flickr user Valdiney Pimenta

Red sediments and algae pigmentation produce the unique red color of this salt lake in Bolivia, which is further contrasted by the white borax islands that are spotted throughout it. Located at more than 13,000 feet above sea level, the lagoon is part of the Andean Fauna National Reserve and is a common roosting spot for a variety of flamingo species.

Kelimutu Volcano, Indonesia

Courtesy of Flickr user NeilsPhotography

This volcano harbors three crater lakes at its summit that are strikingly different from one another in terms of color. Typically, Tiwu Ata Mbupu (Lake of Old People) appears blue, Tiwu Nuwa Muri Koo Fai (Lake of Young Men and Maidens) green, and Tiwu Ata Polo (Bewitched or Enchanted Lake) either black or red, although they all are known to change shades quite frequently and unpredictably. The latter two are separated by a crater wall, creating a stunning distinction when viewed side-by-side, especially when they are green and black, as seen in the photo. Thus far, research has revealed no official explanation for the differences and changing colors, but the general consensus is that chemical reactions are being triggered by volcanic gas activity that drives nutrient-rich water to the surface.

Lake Pukaki, New Zealand

Courtesy of Flickr user Peter Nijenhuis

Glacial erosion fills this body of water with glacier flour, or finely-ground rock particles, resulting in a frosty, cloudy-blue color (this mixture is sometimes referred to as glacial milk). Lake Pukaki has a surface area of approximately 111 square miles and was formed when glacial debris known as moraine dammed up the valley. There are glacier lakes in at least a dozen countries throughout the world that take on this “milky” appearance. While they are not abnormally colored, the Great Lakes are the largest glacial lakes in the world.

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Why Are Mugshots Made Public Before a Suspect is Convicted by the Court?
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Jennifer Ellis:

Several reasons.

1. Mugshots can help find people when they have absconded, or warn people when someone is out and dangerous. So there is a good reason to share some mugshots.

2. Our legal system requires openness as per the federal constitution, and I imagine most if not all state constitutions. As such, this sort of information is not considered private and can be shared. Any effort to keep mugshots private would result in lawsuits by the press and lay people. This would be under the First and Sixth Amendments as well as the various Freedom of Information Acts. However, in 2016 a federal court ruled [PDF] that federal mugshots are no longer routinely available under the federal FOIA.

This is partially in recognition of the damage that mugshots can do online. In its opinion, the court noted that “[a] disclosed booking photo casts a long, damaging shadow over the depicted individual.” The court specifically mentions websites that put mugshots online, in its analysis. “In fact, mugshot websites collect and display booking photos from decades-old arrests: BustedMugshots and JustMugshots, to name a couple.” Some states have passed or are looking to pass laws to prevent release of mugshots prior to conviction. New Jersey is one example.

a) As the federal court recognizes, and as we all know, the reality is that if your picture in a mugshot is out there, regardless of whether you were convicted, it can have an unfortunate impact on your life. In the old days, this wasn’t too much of a problem because it really wasn’t easy to find mugshots. Now, with companies allegedly seeking to extort people into paying to get their images off the web, it has become a serious problem. Those companies may get in trouble if it can be proved that they are working in concert, getting paid to take the picture off one site and then putting it on another. But that is rare. In most cases, the picture is just public data to which there is no right of privacy under the law.

b) The underlying purpose of publicity is to avoid the government charging people and abusing the authority to do so. It was believed that the publicity would help protect people. And it does when you have a country that likes to hide what it is up to. But, it also can cause harm in a modern society like ours, where such things end up on the web and can cause permanent damage. Unfortunately, it is a bit of a catch-22. We have the right to know issues and free speech rights smack up against privacy rights and serious damage of reputation for people who have not been convicted of a crime. The law will no doubt continue to shake out over the next few years as it struggles to catch up with the technology.

This post originally appeared on Quora. Click here to view.

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What Happens When You Flush an Airplane Toilet?
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For millions of people, summer means an opportunity to hop on a plane and experience new and exciting sights, cultures, and food. It also means getting packed into a giant commercial aircraft and then wondering if you can make it to your next layover without submitting to the anxiety of using the onboard bathroom.

Roughly the size of an apartment pantry, these narrow facilities barely accommodate your outstretched knees; turbulence can make expelling waste a harrowing nightmare. Once you’ve successfully managed to complete the task and flush, what happens next?

Unlike our home toilets, planes can’t rely on water tanks to create passive suction to draw waste from the bowl. In addition to the expense of hauling hundreds of gallons of water, it’s impractical to leave standing water in an environment that shakes its contents like a snow globe. Originally, planes used an electronic pump system that moved waste along with a deodorizing liquid called Anotec. That method worked, but carrying the Anotec was undesirable for the same reasons as storing water: It raised fuel costs and added weight to the aircraft that could have been allocated for passengers. (Not surprisingly, airlines prefer to transport paying customers over blobs of poop.)

Beginning in the 1980s, planes used a pneumatic vacuum to suck liquids and solids down and away from the fixture. Once you hit the flush button, a valve at the bottom of the toilet opens, allowing the vacuum to siphon the contents out. (A nonstick coating similar to Teflon reduces the odds of any residue.) It travels to a storage tank near the back of the plane at high speeds, ready for ground crews to drain it once the airplane lands. The tank is then flushed out using a disinfectant.

If you’re also curious about timing your bathroom visit to avoid people waiting in line while you void, flight attendants say the best time to go is right after the captain turns off the seat belt sign and before drink service begins.

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