The main difference between euryhaline and stenohaline is that euryhaline organisms can adapt to a wide range of salinities, whereas stenohaline organisms can only adapt to a narrow range of salinities. Furthermore, euryhaline organisms can survive either in freshwater, saltwater or brackish water, while most freshwater stenohaline organisms are unable to survive in salt water and vice versa. Therefore, euryhaline organisms mainly inhabit estuaries and tide pools with regularly changing salinities, and some of them migrate between freshwater and saltwater during their life cycle. On the other hand, stenohaline organisms are fixed into either saltwater or freshwater habitats.
Euryhaline and stenohaline organisms are two types of aquatic organisms with adaptations to different levels of salinities.
Key Areas Covered
1. What are Euryhaline Organisms
– Definition, Features, Importance
2. What are Stenohaline Organisms
– Definition, Features, Importance
3. What are the Similarities Between Euryhaline and Stenohaline Organisms
– Outline of Common Features
4. What is the Difference Between Euryhaline and Stenohaline Organisms
– Comparison of Key Differences
Key Terms
Euryhaline, Osmoconformers, Osmoregulation, Osmoregulators, Salinity, Stenohaline
What are Euryhaline Organisms
Euryhaline organisms are a type of mostly marine organisms with the ability to adapt to a wide range of water salinities. For example, a fish called molly can live in freshwater, brackish water, and saltwater. Also, the green crab, an invertebrate, can live in both saltwater and brackish water. However, most of the euryhaline organisms live in tide pools and estuaries. Generally, these habitats regularly change their salinities. Some euryhaline organisms migrate between freshwater and saltwater habitats during their life cycle. Some examples of such organisms are salmon, eels, etc.
Figure 1: The Movement of Water and Ions in Saltwater Fish
Furthermore, euryhaline organisms are isotonic to the outside environment they live. However, their ionic composition may differ from that of the sea water. Generally, freshwater fish actively uptake salts through their gills. Then, water will diffuse into the body, and by expelling very hypotonic urine, all the excess water can be removed from the body. On the other hand, saltwater fish actively remove salts through their gills and drink more water to keep a lower osmotic concentration inside their body. Therefore, they are osmoconformers.
What are Stenohaline Organisms
Stenohaline organisms are another type of aquatic organisms with the ability to adapt to a narrow range of salinities. Therefore, many freshwater fish such as goldfish may die when put into the salt water. On the other hand, many saltwater fish such as haddock may die when put into the freshwater. Some fish may even burst if they are put into freshwater.
Figure 2: Goldfish
Furthermore, stenohaline organisms are generally osmoregulators. Therefore, they can actively regulate salt concentrations inside their body according to the salt concentrations in the outside environment. When they live in freshwater, they take up more water from the environment, which is hypotonic. However, this is not by drinking water but, by absorbing water through the skin. Moreover, they produce a lot of very dilute urine and take up salts through their gills to achieve electrolyte balance.
Figure 3: The Movement of Water and Ions in Freshwater Fish
In contrast, when they move into salt water, they drink more water, which is hypertonic. Moreover, they excrete excess salts through their gills and urine.
Similarities Between Euryhaline and Stenohaline Organisms
- Euryhaline and stenohaline organisms are two types of organisms adapted to different levels of salinities.
- Both are aquatic organisms.
- They have different levels of osmotic regulation in their bodies.
Difference Between Euryhaline and Stenohaline Organisms
Definition
Euryhaline refers to the ability of an aquatic organism to adapt to a wide range of salinities, while stenohaline refers to the ability of an aquatic organism to adapt to a narrow range of salinities. Thus, this is the main difference between euryhaline and stenohaline.
Significance
Furthermore, euryhaline organisms can survive either in freshwater, saltwater or brackish water, while most freshwater stenohaline organisms are unable to survive in salt water and vice versa.
Importance
Moreover, euryhaline organisms can live in regularly changing salinities, while stenohaline organisms can live in either freshwater or saltwater.
Osmoregulatory Mechanism
Also, another difference between euryhaline and stenohaline organisms is that euryhaline organisms are osmoconformers, while stenohaline organisms are mainly osmoregulators.
Marine or Aquatic
Besides, euryhaline organisms are mostly marine, while stenohaline organisms can be either marine or freshwater organisms.
Examples
Molly, green crab, salmon, eels, herring, etc. are the examples of euryhaline organisms, while goldfish, haddock, etc. are the examples of stenohaline organisms.
Conclusion
Euryhaline organisms are a type of aquatic organisms that are adapted to live in a range of habitats. Therefore, this type of organism can survive in all freshwater, brackish water, and saltwater habitats. In contrast, stenohaline organisms are another type of aquatic organisms only adapted to a narrow range of salinities. Therefore, they only can live in either freshwater or saltwater habitats, but not in both. Hence, the main difference between euryhaline and stenohaline organisms is the ability to tolerate salinities.
References:
1. Learning, Lumen. “Osmoregulators and Osmoconformers.” Lumen – Biology for Majors II, Available Here.
Image Courtesy:
1. “Osmoseragulation Carangoides bartholomaei bw en2” By Kare Kare modified by Biezl translation improved by smartse (CC BY-SA 3.0) via Commons Wikimedia
2. “Peixe010eue” By Luis Miguel Bugallo Sánchez (Lmbuga)Copyright: GFDL (GNU Free Documentation License)Publish by: Luis Miguel Bugallo Sánchez – Galipedia, a wikipedia galega (CC BY-SA 3.0) via Commons Wikimedia
3. “Bachforelle osmoregulatoin bw en2” By Raver, Duane; modified by Biezl translation improved by User:smartse – NOAA. Transferred from en.wikipedia to Commons by User:Quadell using CommonsHelper. (Public Domain) via Commons Wikimedia
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