Whale Fall Ecosystems: How Do They Affect Oceanic Cycles?

Francisco Sack

Have you ever wondered what happens to a whale when it dies? Though we often hear of tragic beaching events and learn about the impact whaling had on populations, most people never wonder what happens to a whale that dies naturally. When a whale dies, it sinks to the sea floor. Due to its sheer biomass, it allows for the creation of its own unique ecosystem. This allows the world of the deep sea to gain access to many of the nutrients that are generated in the shallows.

What is a Whale Fall Ecosystem?

When any type of waste or detritus is generated in the open water of the ocean, gravity causes it to drift slowly down to the sea floor. Typically, these particles are small, the size of a crumb, or, at most, a few centimeters, and are called marine snow. However, they can be larger, in the form of dead organisms such as fish and birds, and are then called food falls. Most notable of these food falls are those of whales, called whale falls. Unlike other food falls, which are typically scavenged within days or less, whale falls remain on the ocean floor for decades supporting their own specialized ecosystems. Their nutrient content is equivalent to two thousand years' worth of marine snow. These ecosystems form in three, possibly four, successional stages.

Mobile Scavenger Stage: In this first successional stage, mobile, or nektonic, animals gather around the whale, both while it is sinking through the water column, and once it hits the sea floor. These organisms, including Greenland sharks, hagfish, and giant deep sea isopods, remove the majority of flesh from the whale in a span of four months to two years.

Enrichment Opportunist Stage: In the second successional stage, there are few chunks of flesh still on the bone, and there are many smaller particles of food around the whale fall. Instead of larger animals such as sharks, smaller organisms like octopuses, crabs, squat lobsters, and mussels colonize the whale. They are able to feast on the smaller skin and flesh particles. In the process of mobile scavengers stripping the skeleton, large expanses of bone are exposed. This opens the whale to a unique scavenger, osedax worms, which are able to consume the bone itself. This stage of the whale fall can last around two years.

Sulfophilic Stage: The most astounding stage of the whale fall ecosystem, even if only for its own unexpectedness, is the sulfophilic stage. Sulfophilic means to be attracted to sulfur, and in this case describes the stage where a chemosynthetic environment forms around the whale skeleton. When osedax worms in the enrichment opportunist stage burrow into the bone of the whale, they allow anaerobic bacteria (able to “breathe” without oxygen) to access the lipids, or fats, inside the bone marrow. As they consume this, they release sulfides as a byproduct. These sulphides then feed chemosynthetic bacteria, a different kind of primary producer. Instead of relying on sunlight to produce glucose, chemosynthetic organisms rely on inorganic substances such as sulfides, methane, and iron. They oxidize, or add oxygen to, these substances, and use the energy produced to create sugars. The presence of these bacteria allows for an entire chemosynthetic ecosystem to develop, including tube worms, chemosynthetic mussels and clams, and snails. This ecosystem stage can support over 30000 organisms on a single skeleton, and can last from ten to over fifty years.

Reef Stage: The reef stage of a whale fall is when the skeleton has been completely stripped bare, and can serve as a home for suspension feeders such as sponges and coral. This stage has been infrequently observed, and is poorly recorded in scientific literature, so there is much to be learned about its ecology and very existence.

What is the Marine Carbon Cycle?

When we think about greenhouse gases, one of the first thoughts that comes to mind is of carbon dioxide, or CO2. This is an example of inorganic, atmospheric carbon. Carbon is also found in all living organisms, called organic carbon. At the surface of the ocean, the point where the air meets the water, called the air-sea interface, CO2 is dissolved into the ocean, where some of it flows downward and is stored as dissolved inorganic carbon in water. CO2 from the water and atmosphere is consumed by photosynthetic organisms such as algae, called phytoplankton, which convert inorganic carbon into organic carbon. Phytoplankton and other marine plants and algae, make up about 20% of the total ocean biomass, and phytoplankton generates at least 50% of the oxygen on earth. This carbon is entrenched even deep into the marine ecosystem through the food web. Zooplankton, microscopic floating organisms, consume phytoplankton and other zooplankton, storing their organic carbon in their bodies. Zooplankton are then consumed by larger organisms such as krill, who are then consumed by fish and whales, as well as other predators. This is called the biological carbon pump. These animals, as well as the process of decomposition, release CO2 into the water and atmosphere again, restarting the process.

What are Marine Nutrient Cycles?

Just like humans, marine organisms need their vitamins. The nutrient cycles of the ocean allow for the growth of phytoplankton, and therefore the entire food web of the sea. Two of the most important nutrients involved are nitrogen and phosphorus. Phosphorus enters the ocean through runoff and the weathering of rocks and minerals, is integrated into organic systems by phytoplankton and bacteria, and can leave the ecosystem through sedimentation, where it is buried in the sea floor. Nitrogen enters the ocean through the air-sea interface and through runoff. It is then “fixed” into an organic form by specialized bacteria, where it is then incorporated into the food web.

Role of Living Whales in Oceanic Cycles

Throughout their lives, whales are in constant movement. They dive deep to hunt, migrate from place to place, and corral and feed on krill. In each of those actions, they play an important role in marine nutrient and carbon cycles. The whale pump is the mechanism by which whales spread nutrients from the deep sea to the surface. They feed at a depth, and then expel feces and urine at the surface, which are full of nutrients such as phosphorus and nitrogen. Additionally, as whales migrate, they initiate the whale conveyor belt, in which they transport nutrients from place to place along their route. These nutrients fuel phytoplankton growth, allowing for more capture of carbon.

Role of Whalefall Ecosystems in Oceanic Cycles

Whales, due to their size and diet, hold a large amount of nutrients and carbon. When they sink, they both store this carbon for hundreds to thousands of years, contributing to the ocean’s carbon sink and conveying nutrients to the deep sea. The deep sea, while generally nutrient rich, is a great expanse, making it difficult for organisms to find suitable food. When the whale arrives, it allows for nutrients to be redistributed to the deep sea, allowing for the biodiversity and ecosystems of the abyss to be sustained.

However, it is important to note that, though the role whale fall ecosystems play in the nutrient and carbon cycles may have a great local influence, they do not play a significant role in the prevention of man-made climate change.

Conclusion

Whales and whale fall ecosystems are not only incredible, majestic symbols of the power of the ocean, but also play a significant role in nutrient and carbon cycling through the sea, especially between depths. Learning more about the world we live in is vital to protecting and conserving it, including understanding how all of its components connect and shape the world we live in.

Citations

Air-Sea Interface | Earth Sciences | Earth Science, Geologic Time & Fossils | Science. (n.d.). Brittanica. Air-sea interface | Definition, Characteristics, & Significance | Britannica

Amon, D. J., Glover, A. G., Wiklund, H., Marsh, L., Linse, K., Rogers, A. D., & Copley, J. T. (2013). The discovery of a natural whale fall in the Antarctic deep sea. Deep Sea Research Part II: Topical Studies in Oceanography, 92. The discovery of a natural whale fall in the Antarctic deep sea - ScienceDirect

Aquatic food webs. (n.d.). National Oceanic and Atmospheric Administration. https://www.noaa.gov/education/resource-collections/marine-life/aquatic-food-webs

Bar-On, Y. M., & Milo, R. (2019). The Biomass Composition of the Oceans: A Blueprint of Our Blue Planet. Cell Press, 179. The Biomass Composition of the Oceans: A Blueprint of Our Blue Planet - ScienceDirect

Dhali, D., & Dhali, D. (2023, February 17). Chemosynthesis. Science Facts. https://www.sciencefacts.net/chemosynthesis.html

Directory, S. (2025, December 1). Marine Nutrient Cycling → Term. Energy → Sustainability Directory. https://energy.sustainability-directory.com/term/marine-nutrient-cycling/

Eleven. (2025, May 6). Why do whales beach themselves? Fish & Wildlife Foundation of Florida. https://wildlifeflorida.org/whales-beach/

Fisheries, N. (n.d.). Whales and carbon sequestration: Can whales store carbon? NOAA. https://www.fisheries.noaa.gov/feature-story/whales-and-carbon-sequestration-can-whales-store-carbon

How much oxygen comes from the ocean? (n.d.). https://oceanservice.noaa.gov/facts/ocean-oxygen.html

Meynecke, J., Samanta, S., De Bie, J., Seyboth, E., Dey, S. P., Fearon, G., Vichi, M., Findlay, K., Roychoudhury, A., & Mackey, B. (2023). Do whales really increase the oceanic removal of atmospheric carbon? Frontiers in Marine Science, 10. https://doi.org/10.3389/fmars.2023.1117409

Stauffer, J. B., Purser, A., Griffiths, H. J., Smith, C. R., & Hoving, H. T. (2022). Food falls in the deep northwestern Weddell Sea. Frontiers in Marine Science, 9. https://doi.org/10.3389/fmars.2022.1055318

The ocean carbon cycle. (n.d.). International Atomic Energy Agency. https://www.iaea.org/topics/oceans-and-climate-change/the-ocean-carbon-cycle

The stages of whale decomposition. (n.d.). [Video]. Natural World Facts. https://www.naturalworldfacts.com/whale-fall-ecosystems

Whale fall | Environmental Sciences | Research Starters | EBSCO Research. (n.d.). EBSCO. https://www.ebsco.com/research-starters/environmental-sciences/whale-fall

What is marine snow? (n.d.). https://oceanservice.noaa.gov/facts/marinesnow.html