The Enrichment Stage

The enrichment opportunist stage is the second stage of succession in the decomposition of a whale which can last up to 18 months depending on the size of the whale carcass (Smith and Baco, 2003). Only 10% of the whale’s soft tissue remains and the skeleton is exposed (figure 3). This stage permits the arrival of sessile organisms which initially settle in the surrounding sediment, as a result of it being organically enriched from the mobile scavenger stage, and will gradually spread to the skeleton. This stage characteristically has high density but low diversity of species with assemblages of opportunistic polychaetes, crustaceans, gastropods and bivalves reaching densities of up to 40 000 per m-2. Sources of organic enrichment, such as sewage outflows, in shallower waters also display a high density but low diversity community (Smith and Baco, 2003).

Towards the end of the enrichment opportunist stage, chemoautotrophic and heterotrophic bacterial mats are present on the surface of the surrounding sediment. The bacteria migrate toward the whale carcass which marks the beginning of the “sulphophilic stage”.

Artists impression of the mobile scavenger stage ©Michael Rotham

Figure 3. Artists impression of the mobile scavenger stage                                ©Michael Rotham

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