Question

On Earth, fish breathe oxygen that is dissolved in the ocean. Do you expect that we will find dissolved oxygen in Europa's ocean? Why or why not? Based on your answer, if we could somehow transport fish to Europa, is it possible that they could survive in the europan ocean? What other types of life from Earth might survive on Europa?

Short answer

No, Europa likely lacks dissolved oxygen necessary for fish. Extremophiles may survive under Europa's extreme conditions.

Step-by-step solution

Understanding Europa's Environment

Europa is one of Jupiter's moons and is covered with a thick layer of ice. Beneath this ice layer, it is believed that there is a subsurface ocean. However, unlike Earth, Europa lacks a significant atmosphere and the presence of life-supporting gases like oxygen is not established.

Evaluating Oxygen Presence

For fish to survive, they need oxygen dissolved in water. However, due to Europa's distance from the Sun and lack of atmosphere, the natural occurrence of oxygen is drastically different from Earth. It is unlikely that Europa's ocean contains the same levels of dissolved oxygen found in Earth's oceans.

Analyzing Fish Survival

If we were to hypothetically transport fish to Europa, the absence of dissolved oxygen suggests that fish would struggle to survive as they require oxygen to breathe. Additionally, the extreme conditions such as temperature and pressure further decrease the survivability of Earth fish in Europa's ocean.

Considering Other Earth Life Forms

Some extremophiles on Earth, such as certain bacteria or archaea, can survive in extreme conditions by metabolizing substances other than oxygen, like sulfur or iron. These types of organisms might have a chance of surviving in harsh environments similar to that of Europa's subsurface ocean.

Key concepts

Europa's environment

Europa is one of the most intriguing celestial bodies in our solar system. It is one of Jupiter's moons, and it is unique in that it possesses a thick ice layer covering its surface. Beneath this frozen shell lies what scientists believe to be a vast subsurface ocean. However, this environment is vastly different from Earth due to its lack of a significant atmosphere. Europa does not have an atmosphere rich in life-supporting gases, particularly oxygen, which is crucial for many forms of life on Earth.

With Europa being far from the Sun, its surface temperatures are extremely cold, about -160 degrees Celsius. These frigid conditions contribute to the thick layer of ice, several kilometers thick, which insulates the subsurface ocean from the cold vacuum of space.


Such an environment presents both challenges and opportunities for astrobiologists exploring the potential for life beyond Earth. Despite the harsh conditions, scientists are keen to explore Europa further, particularly with missions such as NASA's planned Europa Clipper, which aims to explore the moon's ice shell and subsurface ocean to assess its habitability.

Earth extremophiles

On our planet, Earth extremophiles are organisms that thrive in extreme conditions found in environments often considered inhospitable to life. These organisms include certain bacteria, archaea, and even some single-celled eukaryotes. They have adapted to survive in extreme temperatures, high salinity, high radiation, or without sunlight, expanding our understanding of the boundaries of life.

• Thermophiles: These extremophiles live in extremely hot environments such as hot springs and hydrothermal vents.
• Psychrophiles: They thrive in extremely cold environments, similar to the conditions on Europa.
• Halophiles: These organisms prefer highly salty environments.
  
  

Extremophiles showcase the incredible adaptability of life, suggesting that under the right conditions, life could potentially exist in the subsurface ocean of Europa. For example, some extremophiles can metabolize sulfur, iron, or other compounds instead of relying on oxygen which could be beneficial in Europa's potentially anoxic ocean. They help scientists consider the kinds of life forms that might exist elsewhere in the universe, in environments that are quite different from those we are familiar with.

Dissolved oxygen in oceans

Oxygen levels in Earth's oceans have crucial implications for marine life. Dissolved oxygen is vital for the survival of fish and other organisms that rely on oxygen for respiration. This oxygen enters the ocean primarily through the atmosphere and is mixed through surface agitation by waves and photosynthesis from marine plants and algae.

However, the situation on Europa is different. With its lack of a significant atmosphere and being much farther from the Sun, the natural processes that lead to dissolved oxygen are not present. On Earth, oxygen solubility also decreases with lower temperatures, which means that Europa's frigid ocean is unlikely to mimic the oxygen levels needed by typical Earth aquatic life.

For fish to survive, they require a steady supply of dissolved oxygen. Yet, Europa's hostile conditions, combined with the absence of an oxygenated atmosphere, imply that Earth fish would find survival there nearly impossible. Nevertheless, understanding dissolved oxygen dynamics is crucial in our search for extraterrestrial life, as we explore how other forms of life might adapt to environments that diverge significantly from Earth's conditions.