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How Do Fish Breathe? The Science Behind Gills

Wouldn’t it be cool if we could breathe underwater like fish? Read on to learn about what kind of crazy biology we would have to have!

Even though fish can live their lives underwater, they still need oxygen to “breathe”. Instead of breathing air, fish must get their oxygen from the water. This process requires large volumes of water to pass through absorption surfaces to get enough oxygen into their bodies using their mouths and gills. These body parts work like a pump to keep water moving over the gas absorption surfaces of the gills.

Surface area is always the answer to most science problems! The more surface area fish have on the gills, the easier

they will be able to absorb oxygen. If the skin on the gills is thin, this also helps. TheĀ  blood passing through the gills is pumped in the opposite direction of the water flowing over the gills. This allows the blood oxygen level to be less than the oxygen level in the water. Oxygen will always want to move to wherever lacks oxygen, this is also known as diffusion. The oxygen can then attach to hemoglobin, a protein in red blood cells that distributes oxygen throughout the body.

When the oxygen moves throughout the fish’s body, it can then diffuse into areas that have too much carbon dioxide. This carbon dioxide will then be carried out of the bodies through the gills. Just like how we breathe out carbon dioxide! Even though we are so different from fish, we still have the same basic anatomical functions!

Interested in learning more about marine biology and how creatures can live underwater? Sign up for one of our marine biology camps! We still have fun-filled 3 weeks of summer left!