Marine mammals are warm-blooded. They can't breathe underwater, so they need to get oxygen from the air. Because of this, some spend their time going between the sea and the land such as turtles, while others spend all of their time in the water, like cetaceans, the whales and dolphins.
When in comes to breathing under water, marine organisms breathe in different ways. Some absorb oxygen through their skin, some rely on gills, and others gulp air into their gas bladders.
An aquatic animal breathes by absorbing free oxygen into its blood through its gills or directly through its body surface. Oxygen (O2) is consumed in surface waters by all aquatic organisms: fish, plants, algae, bacteria, and invertebrates.
How do marine animals survive in water without air contact?
Water contains dissolved oxygen from plant life within marine ecosystems (such as algae and seaweed) and organisms such as phytoplankton. Marine animals have specialised features that enable them to take up this oxygen through diffusion such as gills or specialized skin.
Over hundreds of millions of years, marine organisms produced over half of the oxygen that animals currently breathe. Phytoplankton - the foundation of the oceanic food chain. Image courtesy of the NOAA MESA Project.
How Do Fish Breathe Underwater? | COLOSSAL QUESTIONS
Does 70% of the world's oxygen come from the ocean?
Oxygen is produced by photosynthesizing organisms that live in the ocean, in fresh water, and on land. These organisms include bacteria, algae and plants. Photosynthesizing algae in the ocean produce around 70% of oxygen in the atmosphere.
Home > About whales & dolphins > How do whales and dolphins breathe? Whales and dolphins are mammals and breathe air into their lungs, just like we do. They cannot breathe underwater like fish can as they do not have gills. They breathe through nostrils, called a blowhole, located right on top of their heads.
But marine biologists recently discovered large numbers of fishes living in the dark depths of the Gulf of California where there is virtually no oxygen. Using an underwater robot, the scientists observed these fishes thriving in low-oxygen conditions that would be deadly to most other fish.
How do animals survive in the deep ocean without oxygen?
Deep-sea fish have also adapted to survive in a low-oxygen environment. Mexican cavefish, for example, have larger red blood cells that produce higher concentrations of haemoglobin, the protein that carries oxygen throughout the body, than fish that dwell near the surface, according to a 2022 study.
How do marine mammals avoid freezing to death while diving?
Animals that spend most of their time in water rely more on blubber, a layer of tissue containing fat, collagen and elastin that provides, among other things, insulation and energy storage like human fat. The amount of blubber varies from one animal to the next.
Fish take water into their mouth, passing the gills just behind its head on each side. Dissolved oxygen is absorbed from—and carbon dioxide released to—the water, which is then dispelled. The gills are fairly large, with thousands of small blood vessels, which maximizes the amount of oxygen extracted.
Amphibians are vertebrates (animals with backbones) which are able, when adult, to live both in water and on land. Unlike fish, they can breathe atmospheric oxygen through lungs, and they differ from reptiles in that they have soft, moist, usually scale-less skin, and have to breed in water.
Even though they live in the ocean all of the time, dolphins are mammals, not fish. Like every mammal, dolphins are warm blooded. Unlike fish, who breathe through gills, dolphins breathe air using lungs. Dolphins must make frequent trips to the surface of the water to catch a breath.
Some sea animals like dolphins and whales do not have gills and they cannot breathe underwater. They breathe in air through blowholes that are located on the upper part of their head.
Is there an ancient technique to breathe underwater?
An Assyrian carving from around 885 BC shows what appears to be armed men using small breathing sacs underwater, allowing them to sneak up on their enemies. In 500 BC, the Greek sculptor Scyllis was said to have used a reed as a snorkel to hide underwater as he cut the enemy Persian ships from their moorings.
NASA did not abruptly stop deep-sea research following the failure of a satellite in 1978. The agency continues to study the deep ocean and launched missions as recently as 2021.
66m depth is of course the maximum recommended depth for dives on air because of the high risk of central nervous system oxygen toxicity convulsions, let alone the severity of nitrogen narcosis at this depth.
The oxygen minimum zone (OMZ), sometimes referred to as the shadow zone, is the zone in which oxygen saturation in seawater in the ocean is at its lowest. This zone occurs at depths of about 200 to 1,500 m (700–4,900 ft), depending on local circumstances.
However, many air-breathing creatures are built for breath-holding. Some species, such as fish, crabs, and lobsters, have the ability to breathe underwater. Other creatures, such as whales, seals, sea otters, and turtles, spend their entire or portion of their lives in the water yet are unable to breathe underwater.
Is there less oxygen the deeper you go in the ocean?
Why deep oceans are losing their oxygen. As you go deeper into the ocean, dissolved oxygen is used up as sinking organic matter rots and decomposes (a process that requires oxygen). In spring, the ocean can form layers which don't mix very much. This isolates the deep water from the atmosphere, a main source of oxygen.
What mammal can survive the longest without oxygen?
Now there's another reason to consider them amazing. New research shows that naked mole rats can survive for hours in extremely low-oxygen environments, and can live for as long as an astonishing 18 minutes without any air at all. The findings may eventually pay off in heart attack and stroke treatments.
If asked, do whales sleep underwater? The answer is simple, YES they do. Their bodies shut down but only half of their mind stays at rest so that they conscientiously remember to breathe. Breathing near the surface where whales sleep allows them to breathe more conscientiously, meaning each and every breath counts.
Rather than keeping oxygen in their lungs like humans do, whales' bodies are specially adapted to store oxygen in their blood and muscles. They have extraordinarily high levels of the oxygen-storing proteins haemoglobin and myoglobin.
Sperm Whales: Sperm whales exhibit a unique sleeping behavior called "vertical sleeping." They suspend themselves vertically in the water column, with their heads down and tails up. This sleep posture is believed to conserve energy while still allowing them to surface and breathe regularly.
