Whale Falls Flashcards
What is the minimum depth of the ocean floor on which whale falls are found?
1 000 metres.
When was the first recorded whale fall?
February 19th 1977.
In which ocean are most recorded whale falls? Why?
In the Pacific ocean. Other oceans are warmer, which speeds up the decomposition of the carcass.
There are four stages of decomposition associated with a whale fall. What determines the phases?
The phases are based on the type of animal feeding off the carcass.
What is unique about whale falls, as opposed to the carcasses of other animals?
Other falls do not progress past the first stage of decomposition, because the carcasses have a lower lipid content.
How long does it take for a whale fall to reach the fourth stage of decomposition?
Up to 100 years.
What is the first stage of decomposition? How long does it last?
“Mobile scavengers”, such as hagfish and sleeper sharks, consume the fatty tissue. This last several months, up to a year and a half.
What is the second stage of decomposition? How long does it last?
“Enrichment opportunists”, colonize the bones and surrounding land. This lasts up to 4 and a half years.
What is the third stage of decomposition? How long does it last?
Bacteria breaks down the fat in the bones, and forms a “bacterial mat” around the carcass. This mat feeds animals living on the ocean floor. This stage can last anywhere from 50 to 100 years.
What is the fourth and final stage of decomposition?
The fourth stage is the “reef stage”. Only minerals from the bones remain.
What is a whale fall?
After it’s death, a whale will float until its lungs deflate. It then sinks to the ocean floor, where deep-sea creatures feed on it.
