Take a deep breath. And then another. One of those breaths came from trees. But the source of the other breath might surprise you. Show “Around 50 percent of the oxygen we breathe comes from phytoplankton,” said Brenda María Soler-Figueroa, a marine biologist at the Smithsonian Environmental Research Center. Phytoplankton are tiny plants that live on the surface of oceans and lakes. Each one is invisible to the naked eye, but when they gather together in great numbers, they can turn a body of water red, green or milky white based on which variety is present. “They come in different sizes and shapes,” Soler-Figueroa said. “For example, some look like a bowl with two tails, or they may have an elongated oval shape, or even a forklike shape. Some have spiny structures, and others have structures that look like a crown.” Like trees and other plants, phytoplankton can absorb sunlight and turn it into energy through a process called photosynthesis. Fortunately for us, photosynthesis also creates oxygen as a waste product, which the phytoplankton and plants expel — just like how humans and other animals produce carbon dioxide when we exhale. Although phytoplankton are tiny, there are a lot of them out there. There can be thousands of phytoplankton in a single drop of water, Soler-Figueroa said. Now imagine an ocean full of them releasing little invisible puffs of oxygen all day long. Of course, providing the air we breathe isn’t the only important thing phytoplankton do. They also serve as the base of marine food webs. Many kinds of animals eat phytoplankton, including whales, jellyfish, shrimp, and small fish. “Although they are very important for the environment and the aquatic ecosystems, phytoplankton can also do harm to the environment,” Soler-Figueroa said. For instance, when there are too many nutrients in the water, often as a result of farmers’ fertilizers getting washed out into the ocean, phytoplankton can multiply rapidly and create what’s known as an algal bloom. The problem with algal blooms, said Soler-Figueroa, is that many of these species produce toxins that can be deadly to other ocean life. In great numbers, phytoplankton can also cause a chain reaction that uses up all of the oxygen in the water and creates what marine biologists call “dead zones,” where most can’t survive. “So they’re important, but as with all life, there needs to be a balance,” Soler-Figueroa said. Perhaps the coolest thing about phytoplankton, apart from providing the oxygen that we breathe, is that some of them can glow. In Puerto Rico, which Soler-Figueroa calls home, you can kayak at night and watch as the water lights up with tiny blue and green fireworks around your paddle. Phytoplankton use the ability to create light, known as bioluminescence, as a way to distract and escape from predators. “You can describe it, but it’s not the same as seeing it,” said Soler-Figueroa. “It’s pretty amazing.” Correction: An earlier version of this story referred to phytoplankton as creatures. They are plants. The story has been updated.
When was the last time you thought about your
breathing? Take a breath right now and think about it. You breathe because you need oxygen, a gas which makes up 21 percent of the Earth’s atmosphere. All that oxygen has to come from somewhere. You might already know that it comes from photosynthetic organisms like plants. But did you know that most of the oxygen you breathe comes from organisms in the ocean? That’s right—more than half of the
oxygen you breathe comes from marine photosynthesizers, like phytoplankton and seaweed. Both use carbon dioxide, water and energy from the sun to make food for themselves, releasing oxygen in the process. In other words, they photosynthesize. And they do it in the ocean. Photosynthesizers have been in the ocean for a long time. Land plants start appearing in the fossil record 470 million years ago, before dinosaurs roamed the earth. But the ocean was producing oxygen for billions of years before that. The oldest known fossil is from a marine cyanobacterium, a tiny-blue green photosynthesizer that was releasing oxygen 3.5 billion years ago. In a way, we owe the ocean for all of the oxygen that comes from land plants as well, because land plants evolved from green marine algae. If there were a race to put oxygen in the atmosphere, the ocean would have one heck of a head start. But the ocean’s long history of photosynthesis would matter very little to us if not for the photosynthesizers that live in it today. Of these, the most impressive is another cyanobacterium called Prochlorococcus. It is estimated to be more abundant than any other photosynthesizer on the planet, and to be responsible for producing 20 percent of the oxygen in the atmosphere. One in every five breaths you take, you owe to Prochlorococcus. Perhaps as amazing is the fact that scientists only discovered this super-abundant photosynthesizer in 1988—less than thirty years ago!  Another of the ocean’s photosynthesizers is impressive for a different reason. Recall that sunlight is necessary for photosynthesis. That means all marine photosynthesizers have to live in what scientists call the “photic zone”—the layer at the top of the ocean that is illuminated by sunlight. The photic zone extends down to about 656 feet (200 meters) below the surface of the ocean, but it’s difficult to put a depth limit on it, because photosynthesizers keep taking photosynthesis down farther than we thought possible. Eight hundred and eighty-six feet below the ocean’s surface, you would barely be able to see light. But a type of red algae called Corallinales nevertheless photosynthesizes at that depth. The red color of Corallinales comes from a pigment which enables it to absorb blue and green light, which is just about the only kind of light that manages to filter down to the improbable depths at which Corallinales lives. This photosynthesizer produces oxygen despite only being able to access the tiniest fraction of sunlight. Science Magazine Whether they evolved the earliest, photosynthesize the most, or dwell the deepest, marine photosynthesizers are indispensable to our survival. If they weren’t around, we wouldn’t be breathing. So, once in a while, take a moment to remember the ocean and its photosynthesizers. They’re helping you out with every breath you take. July 2017 Where does the oxygen come from in photosynthesis?During photosynthesis, plants take in carbon dioxide (CO2) and water (H2O) from the air and soil. Within the plant cell, the water is oxidized, meaning it loses electrons, while the carbon dioxide is reduced, meaning it gains electrons. This transforms the water into oxygen and the carbon dioxide into glucose.
Does the oxygen we breathe come from photosynthesis?That's right—more than half of the oxygen you breathe comes from marine photosynthesizers , like phytoplankton and seaweed. Both use carbon dioxide, water and energy from the sun to make food for themselves, releasing oxygen in the process. In other words, they photosynthesize.
Where do we get oxygen to breathe?The Respiratory System. The body needs oxygen for energy. It gets this oxygen from the air around you. When you breathe in through your nose or mouth, you pull air into your throat and down the windpipe.
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Where does the oxygen that we breathe come from in photosynthesis
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