Whalefalls

Whalefalls are the carcasses of large whales that sink to the ocean floor, creating temporary but highly productive deep-sea ecosystems. A dead whale may reach the seabed intact or partly collapsed, delivering a pulse of nutrients that supports a community distinct from the surrounding habitat.

Ecological succession starts with mobile scavengers that remove soft tissues; large predators and scavenging crustaceans such as sharks, hagfish, and crabs feed on the carcass (scavenger stage). As tissues are depleted, smaller invertebrates and opportunists colonize the remains and surrounding sediments (enrichment/opportunist stage).

Over time, microbial processes decompose the bones and release sulfide, attracting sulfophilic communities. Bone-eating polychaetes of the genus Osedax colonize the bones, along with chemoautotrophic bacteria and other specialized invertebrates; this stage can last years to decades. Eventually the skeleton becomes a hard substrate for a long-lived reef-like community, including barnacles, bivalves, and other organisms, persisting long after most tissue is gone.

Whalefalls are widely distributed in the world’s oceans, and scientific observations in deep-sea expeditions reveal distinctive faunal assemblages and a characteristic successional sequence. They provide key insights into deep-sea energy transfer, decomposition, and the evolution of specialized communities around large organic falls.

Because whalefalls are episodic and geographically scattered, they are of particular interest to marine ecologists studying nutrient pulses, colonization, and the factors that structure deep-sea biodiversity. They also offer models for understanding fossil whale bone remains and potential biotechnological applications of bone-degrading organisms.