If you see a starfish and see its amazing movement into the water during fast tides, you may be amazed at the starfish’s body. Interestingly, they do not have any organs like lungs or gills, as other animals do. then, how do starfish breathe?
So, without any ado, let’s explain that Starfish breathe through tiny things called papulae. These are found on their belly side. Papulae are like small, thin walls that help oxygen from the seawater get into the starfish’s body. The starfish’s tube feet also help move water all around its body, which helps with breathing. This process is called diffusion.
But, it doesn’t end here, and the whole story is not revealed.
Below, I’ll explain the biology of starfish breathing organs and how they use them.
What Are Starfish Breathing Organs? (Gills or Lungs)
Despite their name, starfish aren’t fish. They lack organs like lungs or gills that most fish and animals use for gaseous exchange, the question arises how do starfish breathe into water, and what are the organs used for breathing?
Starfish rely on two primary organs for gaseous exchange:
1. Papulae or Skin Gills
Papulae are lots of thin walls on the top of a starfish. They work like tiny gills. They have extra parts connected to their main body, which helps them breathe better by taking in oxygen and letting out carbon dioxide. Collagen fibers support these delicate dermal gills.
2. Tube Feet (pedicellariae)
Hundreds of tube-like structures are on the Starfish’s underside of sea stars. Tube feet starfish function in locomotion, respiration feeding, and sensory perception.
Their thin walls might not let a lot through, but they breathe through tiny things called papulae on the top of the starfish.
Even though it’s not a real heart system, the water system helps starfish move by stretching and squeezing their tube feet. It also helps them find food and sense what’s around them.
Because starfish have lots of organs and move slowly, they can take in oxygen from their surroundings really well. Starfish are also good decomposers of the ocean cleaning dead organic matter.
Do Sea Stars Have Gills? Starfish Breathing (Respiratory System) System Explained
Starfish do not possess true gill structures but have a unique respiratory system. Let’s look at each part and see how the starfish breathing technique works. Starfish have an open circulatory system where water flows freely within a coelom cavity. The tiny structures called papulae, equipped with cilia, generate a water current.
As this current draws seawater into the body, the dissolved oxygen in the water diffuses into the coelomic fluid and then into the Starfish’s cells. The thin, semi-permeable membrane lining the papulae facilitates this diffusion process.
When carbon dioxide CO2 accumulates in the Starfish’s body, it diffuses with other waste products like ammonia(NH3). This diffusion occurs from areas of high concentration (inside the body) to areas of low concentration (the surrounding water).
Coelom of Starfish
The coelom is a body cavity that lines Starfish’s digestive system and other organs. It is not directly open to the environment but is lined with cilia, which help to circulate coelomic fluid throughout the body.
Papulae are finger-like projections of the body wall that increase the surface area for gas exchange. They are lined with cilia, which help to draw water into the coelom. Gas exchange occurs across the thin walls of the papulae. Oxygen(O2) from the water diffuses into the coelomic fluid, while carbon dioxide (CO2) diffuses out of the coelomic fluid and into the water.
Coelomic fluid circulates throughout the body, transporting oxygen to tissues and carbon dioxide away from tissues. The coelom serves diverse animal functions, including supporting organs, providing structural support, and transporting fluids and gases.
However, unlike specialized organs like gills, lungs, or skin, it’s not only responsible for respiration or excretion. However coelomic fluid may aid internal gas transport. It doesn’t directly exchange them with the environment. Nutrient uptake also bypasses the coelom via the digestive and circulatory systems.
The Water Vascular System’s Function
Now, let’s examine the structure of the starfish water vascular system.
Starfish tube feet, or podia, function as “secondary gills” and aid in gas exchange. They are connected to a network of canals inside the sea star’s body called the water vascular system. Seawater enters through a pore called the madreporite
located on the upper side of the sea star’s body, slightly off-center during water circulation. It then flows into a tube called the stone canal. The stone canal connects with the ring canal, which circulates the center of the sea star’s body and connects with radial canals.
Each radial canal extends throughout an arm’s length, terminating at the tip. Each radial canal branches into two short and narrow branches called lateral canals. Each lateral canal has a valve preventing water from flowing back into the radial canal.
They connect with the base of the tube feet, which each have a sucker or adhesive disc at the end. The ampullae, located near the base of the tube feet, contract by squeezing water into the tube feet, causing them to extend.
When relaxed, the elastic tissue of the tube feet pulls them back, creating suction. Allows the Starfish to move, adhere to surfaces, capture prey, and perform other important functions. While they can be found in coral reefs, Starfish exist in diverse marine environments with suitable rocky or hard surfaces.
How Do Sea Stars Breathe Underwater?
Despite their name, Starfish aren’t fish and lack lungs or gills. So, how do sea stars breathe underwater? How does the starfish respiration system work?
Well, we will explain it below. Just look at this magical creature, how beautiful it is.
Sea Star or starfish breathing technique relies on two unique features:
1. Papulae
The tiny, thin-walled projections on the Starfish’s topside. Which act like gills. They increase surface area, allowing dissolved oxygen in water to diffuse into the Starfish’s body. Cilia, tiny hair-like structures, create water currents around the papulae, aiding in gas exchange.
2. Tube Feet
There are hundreds or thousands of tube-like structures on the Starfish’s underside of the sea star. Tube feet starfish function in locomotion, respiration feeding, and sensory perception.
The Respiratory System of Starfish (How Starfish Breathe)?
Seawater enters the madreporite (pore) and flows through the water vascular system. Papulae create currents, drawing water in. Dissolved oxygen diffuses through the thin papulae walls into the coelomic fluid (body cavity).
The coelomic fluid transports oxygen to cells throughout the body. Carbon dioxide diffuses from cells back into the coelomic fluid and then through the papulae.
Key Points of This Star Fish Excercise
- Starfish have a unique, open circulatory system where water flows freely within the coelom. Papulae increase surface area for efficient gas exchange.
- Tube feet aid in water circulation but primarily contribute through their connection to the papulae.
- This system works well for slow-moving Starfish in environments with adequate oxygen.
How Do Starfish Breathing Occurs? (Gills or Lungs?)
Starfish lack specialized organs like gills or lungs. They breathe through tiny structures called papulae, which are located on their underside.
Papulae are thin-walled projections that allow dissolved oxygen in the seawater to diffuse into the Starfish’s body. The Starfish’s tube feet also help to circulate water throughout its body, which further aids in gas exchange, this process is called diffusion.
Gas exchange occurs across the entire surface of the papulae, not just specialized membranes. The coelomic fluid doesn’t directly exchange gases with the environment but aids internal transport.
Can Starfish Breathe Out of Water?
- Starfish cannot breathe out of water. It is important to never remove them from their natural environment (the water) for any reason.
- Even 20 seconds is too long for most species, as they can only hold their breath for around 30 seconds.
- Exposing them to air deprives them of oxygen and leads to suffocation from carbon dioxide build-up, not intoxication. Carbon monoxide poisoning is unlikely in this scenario.
- It is crucial to leave Starfish in the water. Removing them, even briefly, can cause great stress and harm. Chemicals and bacteria on our skin can harm our health and may even be fatal for them.
Respect wildlife
Leave all marine life, including Starfish, in their natural habitats. Observe them responsibly without touching or disturbing them. I proudly say I always guide people not to disturb these innocent creatures unnecessarily.
Spread the word: Tell others how important it is to keep starfish in the water to help protect them.
Brittle Star Classification(Do they breathe like sea stars)?
Brittle stars, or serpent stars or ophiuroids, of phylum Echinodermata, the same group as sea stars, sea urchins, sand dollars, and sea cucumbers. They are classified in the class Ophiuroidea, which contains over 2,000 species. Unlikely, brittle stars don’t have lungs and don’t “breathe” like us. They absorb oxygen and release CO2 through tiny structures on their arms.
Also Read:
- Are Starfish Poisonous? 8 Exciting Facts You Didn’t Know
- How to Clean Seashells Like a Pro [12 Bonus Tips ]
- Top 5 Seashell Identification Apps Recommended By A Marine Biologist
FAQs( Frequently Asked Questions)
What are 08 Examples of Starfish, breathing in Florida Waters?
Florida has different types of starfish, like the Nine-Armed Sea Star, Common Comet Stars, Forbes Sea Star, Gray Sea Star, Red Cushion Starfish, Orange Ridged Sea Star, Conical Spined Sea Star, and Two-Spined Sea Star.
Starfish Breathe Through Lungs?
No! Starfish lack lungs & gills. They absorb oxygen across their body surface & release CO2 into the water.
Does Starfish Breathe Through Skin?
Yes, starfish respiratory system is totally dependent on their skin, through which they absorb the oxygen from ocean waters.
How Do Tube Feet Work In Red Cushion Starfish?
Red cushion starfish use their many tube feet for lots of things, like moving around, feeling things, eating, and breathing.
How Do Starfish Breathe In The Freshwater of Florida?
Starfish don’t have lungs! They absorb oxygen from seawater through tiny sacs on their underside. So yes, Florida starfish can “breathe” fine in Florida’s salty waters.
Can a Starfish With 9 Legs Breathe The Same as 5 Starfish?
9- and 5-legged starfish “breathe” through tiny sacs, not lungs. Number of legs doesn’t affect this. They absorb oxygen from seawater, making them salty breathers, no matter their leg count
Conclusion
The query how do starfish breathe in the ocean is explained in an easy way, starfish use tiny structures called papulae and tube feet to take in oxygen from the water and get rid of carbon dioxide. This helps their cells get the energy they need.
Starfish can only breathe in water, so it’s important to keep their ocean home clean and safe, starfish themselves are also good decomposers of the oceans.
