If a Whale Decays in the Ocean, What Happens?
By Amidia Frederick
Mori Point was abuzz with excitement this spring with the appearance of two whales. The San Francisco Recreation & Parks Department and the city of Pacifica buried the humpback and sperm whale on May 19, completing the burial over the course of two days. The original decision was to let the whales decompose naturally, but surrounding communities soon realized what a powerful aroma such a natural process can produce.
A whale carcass becomes a cornucopia of fascinating mechanisms of decay. Cells and tissue break down by enzymes, bacterial decomposition, fermentation, and putrification—the liquefaction of organs and protein. As a result, noxious gases such as carbon dioxide, hydrogen sulfide, and ammonia accumulate within the body cavity, causing severe bloating. The gases eventually find a crevice or weak fissure to release through—causing a sudden explosion.
Thankfully, both whales had a necropsy conducted by the Marine Mammal Center and California Academy of the Sciences, releasing the pressure before such an explosion could occur.
Whale carcasses do provide an abundance of resources for wildlife both on land and underwater. When whale carcasses float in the open ocean they sink to the floor after the gases are released, a process called a “whale fall.” After they hit the ocean floor, scavengers such as hagfish and amphipods devour 40–60 kg of tissue a day. In less than a year, all organic material is gone, leaving behind the oil and fats deep within the skeleton.
Bacteria that consume the oils and fats release hydrogen sulfide, which attracts other deep sea creatures. Sulfide is a key ingredient for rich ocean floor communities. The bones of a whale also provide a hard surface for colonization. Organic matter not consumed in the frenzy is dispersed throughout the surrounding area, providing nutrients to ocean floor sediments. Whale falls can support deep-sea invertebrates and microbial communities of 100+ species for up to 200 years.
Scientists have continued to study the incredible ecological succession that evolves from a whale carcass. Unfortunately, because of the fumes, most residents and visitors would prefer to read about the process than experience it. Decomposition is a natural process in the richness of life but often one that is grotesque and unappetizing.
However, I still wonder what type of communities would have developed on the sperm and humpback whales if they were left to decay in the open. Is it possible we are taking away vital ecosystem processes by burying the whales? How do we negotiate between natural events of ocean ecosystems and the human habitats they border? These questions (and their answers) are ever-evolving, but I would like to give thanks to the whales for giving us a moment to pause, marvel, and appreciate.