By Elizabeth Ann McNulty 

Introduction   

About 22% of all marine animals are currently at risk of extinction. Yet, throughout the history of the Earth, marine species have evolved to possess extraordinary adaptations, such as bioluminescence, camouflage, and specialized body structures, which help them adapt to their changing environments and the threat of human activities. The unique adaptations reveal the resilience of life in the ocean, as countless aquatic species have thrived because of the adaptations they have evolved. Although many aquatic organisms have evolved remarkable traits for survival, modern challenges such as climate change, overfishing, and pollution continue to put them at risk.  

Main Threats to Ocean Life  

Marine animals face natural challenges and human-caused challenges on a daily basis. Charges such as predation on the species at the bottom of the food chain have always been a natural aspect of life in the ocean. However, there have been threats from human activity, including overfishing, pollution, and most significantly, climate change.  

The oceans have been becoming increasingly warmer and more acidic over the years, and since water expands as it gets warmer, sea levels rise, which has a significant impact on marine habitats. Another threat to ocean life is overfishing, which happens when fishing disrupts the health of the ecosystem by changing the predator-prey balance, reducing biodiversity. It can also harm the sea floor of the ocean animals’ habitats. (Threats, n.d.).  

More than 80% of marine pollution comes from land-based activities. A common example of this is when sea turtles accidentally eat pieces of plastic, thinking that they are jellyfish, which can cause fatal intestinal blockages and digestive problems. Around 80% of all marine debris is from plastic. The National Ocean and Atmospheric Administration (NOAA) estimates that anywhere from around 20 million to 1.8 billion pieces of plastic would be found around the coastlines of the United States (Marine debris, n.d.).  

Natural Selection  

Natural selection is the primary mechanism of evolution through which populations adapt and evolve traits that allow them to survive and reproduce in their environment. This process occurs over the course of many generations within the same species,  

Individuals who have traits better suited for their environment are more likely to pass on those traits to their offspring. Over time, the helpful trait that was selected for gradually becomes more common in that population. The process of natural selection is essential for ocean animals to develop adaptations that will help them survive changes to their environment (Marine organisms, n.d.).   

Ocean animals can adapt to some changes in their environment due to pollution, but they can’t adapt to vast changes that destroy their natural habitat. Unfortunately, ocean pollution moves through populations much faster than ocean life can adapt to its environment.  

Marine Animal Adaptation Examples  

Ocean wildlife display a diverse range of adaptations to survive in their environments, including bioluminescence, locating prey with specialized senses, and streamlined bodies. 

Bioluminescence is the ability of some living organisms, such as jellyfish, to produce light through chemical reactions. Marine animals that are deeper than 200 meters are unable to rely on photosynthesis or vision, where sunlight no longer penetrates the water. Since many sea animals can’t see in deep ocean waters, bioluminescence helps them find food and spot potential danger. (How far, n.d.). 

Another example of an ocean animal adaptation is camouflage, which helps to hide from predators. Sting rays camouflage themselves by staying near and burying themselves in the ocean floor as a behavioral adaptation to help them hide from predators. In addition, many jellyfish are transparent, allowing them to hide from their predators more easily. However, some sea animals have evolved with a strategy opposite to camouflage. For example, sharks have evolved the unique ability to sense faint electric fields of other sea creatures to help them find prey. This is because of their Ampullae of Lorenzini, which are sensory organs on sharks. 

(Amazing Adaptations, 2024).  

The image above shows the Ampullae of Lorenzini (Shark, n.d.) 

Cetaceans like whales and dolphins evolved specialized vertebrae that move their tails up and down. This unique movement supports their large size and makes it more efficient for long-distance travel, and contrasts with the side-to-side tail movement that can be found in most fish (Heywood, 2024). All these adaptations allow these marine creatures to be well-suited to their environments. Above is an image displaying the up and down tail movement of dolphins (How does, n.d.). 

Conservation Efforts  

Currently, conservationists are working to make expansive marine reserves for the future health of our oceans by protecting biodiversity. Maintaining biodiversity in the ocean is essential because it plays a key role in our ecosystem and helps regulate our climate. Oceans absorb lots of carbon dioxide every year to help the climate of our planet remain moderate. In addition, biochemists have studied the natural defense mechanisms of marine species, and their compounds have made a significant contribution to the discovery of new medicines. Marine parks and other protective areas for marine species help sea creatures live longer, and help endangered animals recover. Anyone can help the ocean by reducing materials that aren’t good for the environment: helping clean up litter on the beach and raising awareness of the challenges these ocean species face. Together, an impact can be made to protect marine life and save those 22% of marine animals from extinction. 

Bibliography: 

Amazing Adaptations of Ocean Animals. (2024, October 23). SeaWorld San Diego Blog. https://seaworld.com/san-diego/blog/ocean-animal-adaptations/  

Heywood, W. (2024, October 15). How whales and dolphins are adapted for life on the water. The Harvard Gazette. Retrieved August 24, 2025, from https://news.harvard.edu/gazette/story/2024/10/how-whales-and-dolphins-adapted-for-life-on-the-water/  

How does a dolphin move? [Photograph]. (n.d.). Young Ocean Explorers. https://www.youngoceanexplorers.com/yoe/video/235268530371  

How far does light travel through the ocean? (n.d.). National Ocean Service. Retrieved August 18, 2025, from https://oceanservice.noaa.gov/facts/light_travel.html#:~:text=Light%20may%20be%20detected%20as,photosynthesis%20is%20no%20longer%20possible.  

Marine debris impacts. (n.d.). U.S. Department of the Interior. Retrieved August 22, 2025, from https://www.doi.gov/ocl/marine-debris-impacts#:~:text=It%20is%20believed%20that%20at%20least%208,debris%20from%20surface%20waters%20to%20deep%2Dsea%20sediments.  

Marine organisms and adaptations. (n.d.). Science Learning Hub. Retrieved August 24, 2025, from https://www.sciencelearn.org.nz/resources/142-marine-organisms-and-adaptations  

Shark-anatomy-ampullae-of-lorenzini-1 [Photograph]. (n.d.). Ocean Treasures Memorial Library. https://otlibrary.com/shark-anatomy-ampullae-of-lorenzini-1/  

Structures and adaptations to marine living. (n.d.). Marine Bio. https://www.marinebio.org/conservation/marine-ecology/structures-adaptations/  

Threats facing our oceans. (n.d.). The Kwanatanga O Aotearoa Department of Conservation. Retrieved August 22, 2025, from https://www.doc.govt.nz/nature/habitats/marine/threats-facing-our-oceans/