Although consuming saltwater can dehydrate and kill organisms, some fish survive by using specialized gills that leach excess salt from their bodies back into the surrounding water.

Some marine life can survive the extreme pressure of the deep ocean because of specialized molecules that strengthen proteins, enzymes, and cellular membranes.

The ocean gets its salt from runoff carrying fragments of eroded rock and from seawater dissolving salts and minerals from magma at seafloor spreading centers.

How water pressure affects the body

The extreme conditions of the deep sea include increasing amounts of pressure as explorers and organisms descend into its depths. The major danger for both fish and humans is the way pressure changes how body tissues absorb chemical molecules...

Desalination involves costly, energy-intensive methods for producing freshwater

Thermal desalination heats saltwater to produce steam, and reverse osmosis forces saltwater through a membrane that only allows water through. In both cases, freshwater is collected and remineralized for consumption, while wastewater brine is often returned to the ocean, where it may harm marine organisms.

How the methods of catching fish for food affects their taste

Commercially caught fish are often killed through suffocation, allowing the causing the fish extreme stress and flooding their bodies with stress hormones and lactic acid. These chemicals cause the fish's flesh to become bitter where it was once rich and quickens the rotting process.

Salt is harvested from briny ocean water and underground deposits

Mostly sodium chloride, this compound is produced for human use by collecting seawater in shallow pans and allowing the Sun to evaporate the water until crystals remain. Underground rock salt is mined, crushed, and purified from deposits left behind by ancient seas that have dried-up.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

In osmotic power systems, the natural movement of water from regions of low to high salt concentration is used to generate electricity from pressurized water.

While nearly all fish are cold-blooded—their body temperatures match their surroundings—the opah, or moonfish, is fully warm-blooded, with a body temperature about 5 degrees Celsius (9 degrees Fahrenheit) warmer than its environment.

An overview of extremophiles and the biochemical adaptations employed by various types

These organisms thrive in environments that would normally be inhospitable to most living things by using molecules that help counter deadly environmental factors. These include antifreeze-like proteins that prevent psychrophiles from freezing and rupturing in polar regions, and osmoprotectants that prevent some extremophiles from losing water to salty environments.

To survive underwater hibernation, some freshwater turtles perform cloacal breathing—blood vessels absorb dissolved oxygen from water drawn into the organism's cloaca, or rear orifice.

The cells of spotted salamander embryos and early-stage larvae harbor algae that support embryonic development by increasing oxygen levels and removing waste.

Breaking down the challenges of alkaline environments and how extremophiles survive them

These areas are far less acidic than the interiors of most organisms' cells, and this imbalance draws protons that are needed for various metabolic processes, including energy production, out of cells. To counter these effects, some alkaliphiles have developed stronger proton regulation across their cellular membranes and proteins that drive these processes with greater stability amid such acidity imbalances.

View colorful flowers that grow on cacti and succulents, popular xerophilic organisms

These dry-loving organisms are able to retain the water they need to grow and reproduce in deserts and arid grasslands through a suite of adaptations, including thick, fleshy stems that store abundant water, a waxy coating that helps prevent water loss, and an uncommon form of photosynthesis that loses less water.

Electrogenic animals generate their own electricity within an electric organ by changing the pattern of electrical charges in disc-shaped cells called electrocytes.

How flooding the Dead Sea could help the climate

There are many dead zones in the world with low elevation and very little rainfall that provide little to no benefits to the ecosystem or climate. This digestible, thorough article explains how piping in nearby water to flood these areas could...

Fish in polar waters contain proteins in their blood that act as antifreeze, and some manufacturers have used lab-grown versions of these proteins to help keep ice cream smooth.

The tongue evolved in animals roughly 350 million years ago

Creatures like fish rely on suction to consume food, flexing their gills to create water currents that vacuum up their meals. The evolution of the tongue enabled vertebrates to completely cut ties with the sea, moving onto land where they could sample new foods and ways to eat them.

A look at how fish less than two inches long climb up 50-foot waterfalls

Shellears use tiny hooks on their front pectoral fins to grip rock like Velcro and take many pauses to recover energy between bursts of movement. Their pectoral girdle—an arch of bone—supports the muscle system needed for the roughly ten-hour climb.

How goldfish cause significant environmental damage when released

Researchers have found that goldfish cause "regime shifts" in habitats as they search for food in places like lake beds, kicking up sediment that muddies the water and disrupts small invertebrates. They can also outcompete native species to further destabilize existing food webs.

Swimming in schools helps some fish conserve energy in turbulent flows

Scientists studying groups of giant danios swimming in turbulent waters found that the fish used up to 79% less energy than they did when swimming individually in the same conditions. The same fish were found to use the same amount of energy in turbulent and calm water when in schools.

Gulf nations produce about 40% of the world's desalinated water

According to a 2023 report, six Gulf states produced 1.9 trillion gallons of freshwater across more than 400 desalination plants along their coasts. These plants create water suitable for human consumption by boiling saltwater and collecting steam or using high-pressure pumps to push seawater through a filter that only allows water molecules through.

Catfish have taste buds spread across their entire skin, making their whole body function like a tongue that can taste food several feet away.

Explaining why salt should be used to season food early in the cooking process

Experiments involving the same dishes, with salt added at the start of cooking versus at the end, have been shown to yield drastically different taste outcomes because salt takes time to diffuse into foods, particularly vegetables, whose cells are surrounded by cellular membranes and walls. Salting at the end will produce a concentrated surface coating, rather than even seasoning.

Why tardigrades are a model extremotolerant species rather than an extremophile

By expelling most of the water from their bodies, water bears assume a state resembling a dried-up cyst and can withstand extreme environments, such as arid deserts. But in this state and these environments, tardigrades cannot grow, reproduce, or perform other functions associated with life, unlike extremophiles like dry-loving xerophiles.

Cats have a mutation that prevents them from tasting sweetness, and goldfish rank among the world's supertasters.

Sea stars are invertebrates—they lack a backbone—and while most exhibit pentametric radial symmetry due to having five arms radiating from a central disk, some can possess more than 40.

Tardigrades can survive in a dehydrated state for decades

Despite being known as water bears, these microscopic creatures can shut down their metabolism when entering cryptobiosis, squeezing more than 95% of the water from their bodies. In this tun state, tardigrades can even survive the vacuum of space.

About 1,500 species of tardigrades have been identified by their unique physiology

Freshwater-bound eutardigrades live on mosses and lichens and are distinguished by variations in the shape and number of claws at the end of their legs. Marine heterotardigrades, which live on algae and deep-sea sediments, have been observed to possess feathers, inflatable appendages, and flagpole-like tails.

To prevent floating away from others while sleeping, sea otters may wrap themselves in kelp or hold paws, using physical contact to form groups known as 'rafts.'

View a gallery of animals found on abyssal plains, hydrothermal vents, seamounts, and other deep-sea habitats.

Oxygen and nutrients are circulated in tardigrade bodies through physical movement

Rather than having a circulatory system, oxygen is directly absorbed through their skin and spreads through a fluid called hemolymph as tardigrades crawl. When molting to grow, they shed their outer skin and stylets—sharp mouth parts used to pierce prey—which are regrown in their salivary glands.

Blood has evolved many times over hundreds of millions of years, resulting in different blood colors and compositions—and there are even some organisms that don't need blood at all.

Research has found that when their symbiotic algae are not producing oxygen via photosynthesis, corals twirl hairlike structures to circulate water and draw oxygen into their outer tissues.

As immobile animals, corals and the organisms that live on them have evolved a suite of chemical compounds to prevent disease and ward off predators they cannot outrun.

Alaska's Bristol Bay hosts the world's largest self-sustaining wild salmon runs

Nearly 50 million of the fish return to the area each year to spawn, sometimes in the same spot they were born. A journalist tracked the supply chain journey of one sockeye salmon from the sea to the customer's plate.

Whale falls—dead whales that have fallen to the ocean's floor—can provide enough food to spawn a local ecosystem of deep-sea organisms that lasts for decades.

Extreme heat puts people at risk of developing kidney stones

It's essential to remain hydrated in summer weather to keep your body healthy, but one reason is to help dilute minerals that naturally build up if they aren't excreted in our water-fueled urine. Doctors recommend people generally drink 64 ounces of water a day and also eat foods with salt to help ward off dehydration.

The Southern Ocean features the Antarctic Circumpolar Current—the largest ocean current on Earth—which encircles Antarctica and creates a unique biogeographical zone.

As part of the up to 15 pounds of seafood they consume daily, sea otters eat urchins that feed on kelp forests—sources of shelter and food to over 800 species—thereby making the marine mammal a keystone species.

The warmest waters in the ocean are found at hydrothermal vents—hot springs on the seafloor that discharge plumes of mineral-rich water.

What's the difference between an ocean, sea, and saltwater lake?

What are the seven seas, the five oceans, and why isn't the Dead Sea considered a sea? This overview provides definitions for each.

Earth's oceans do mix, despite viral images and videos claiming to show boundaries between oceans that waters do not cross.

We can get food poisoning from spending time in swimming pools, lakes, rivers, and ponds

Some of the same pathogens that may sicken us in food or water may also sicken us in recreational swimming environments. Bacteria can rub off of people’s (or animal’s) bodies or contaminate the water through a diarrheal episode. Washing your hands for at least 20 seconds before eating food if you are at the beach, pool, or other similar environments and being sure not to swallow the water are ways to help keep safe.

One jellyfish species is biologically immortal

Turritopsis dohrnii is a type of jellyfish that can revert back to a juvenile stage after reaching sexual maturity, theoretically allowing it to stay alive for good. But that's a tough sell in a world full of predators. See this list of some of the longest-living species on Earth.

Some invasive species can provide benefits to ecosystems over time

In the 1990s, round gobies were introduced into the Great Lakes, rapidly spreading and competing with local sculpin and logperch. However, Lake Erie watersnakes, which were on the endangered species list, shifted their diet to be almost entirely made up of the plentiful round gobies, contributing to their loss of endangered status in 2011.

Ear infections can arise from chlorinated water, too

Any water remaining in the ear can lead to swimmer's ear. Chlorinated water, however, can also strip the skin of the oils and wax that would otherwise protect the ear.

Oral rehydration solution was developed in the 1960s in response to cholera deaths.

The halting of human bone growth helps manage heat produced from metabolism

While fish, amphibians and reptiles get bigger throughout their lives until they die, their slower metabolisms allow their bodies to regulate the resulting smaller temperature increases. In humans, hormones triggered during puberty harden growth plates, ending bone lengthening.

Scientists have collected critical minerals from ocean water using seaweed, a type of algae that leaves behind a mineral-rich powder called bio-ore after being processed into biofuels.