Whale Falls

Question 1

Food Fall Overview

Answer 1

Represent significant pulse of nutrients to the deep sea
Fish, Whale, other carcasses
Very quickly colonized and devoured
Many new species found associated with these food falls

Question 2

Three Successional Stages of Whale Falls

Answer 2

Mobile Scavenger Stage: months to years
Enrichment opportunist stage: months to years
Sulphophillic stage: decades

Question 3

Mobile Scavenger Stage

Answer 3

4 months to 1.5 years
Deep-sea necrophages remove soft tissues
Dominated by hagfish

Based on soft whale meat
It Starts from 0.5 to 1.5 months after settling
Hundreds of hagfish (up to 800)
Sleeper sharks remove much of the soft tissue
Exact length depends on carcass size

Question 4

Enrichment Opportunist stage

Answer 4

1-2 years
Organically enriched sediments and exposed bones colonized by dense assemblages of opportunistic polychaetes, crustaceans and bacteria
20 000 to 45 000 individual per m^2
Stage ends when O2 is used up

Colonization of organically enriched sediments
Bone eating epifauna (Osedax)

Question 5

Osedax

Answer 5

Specialization for eating of bones
Female is a large organism with male attached giving constant fertilization
Have heterotrophic endosymbiont that digests the bone material
Many different species occupy different niches

Question 6

Sulphophilic Stage

Answer 6

2-50 years
Species-rich, trophically complex assemblages live on the skeleton as it emits hydrogen sulphide from the anaerobic breakdown of bone lipids

Anaerobic decomposition of bone lipids
Sulfate reduction via heterotrophic bacteria - effluxed Hydrogen sulfide
Sulfide oxidizing chemoautotrophic bacteria

Question 7

Importance of Whale Fall Communities (4)

Answer 7

Biodiversity hotspots in the deep sea
Hypothesized stepping stones for HTV species
Unique habitats for a range of specialists
The majority of threats is from declines of whale populations