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A critical evaluation of whales as ecosystem engineers
Paul Wassmann, Martin Biuw and Tore Haug
Based upon a system ecological perspective, the role of the great whales for world ocean ecosystem engineering is investigated. The function of the whale pump for the recycling of limiting nutrients for primary production and for the sequestration of carbon on the sea-floor is explored. The former is significant in the Southern Ocean, but negligible in the Northern Pacific and Atlantic Oceans. The whale pump has probably no impact on the latter, the vertical export of carbon. Nutrients from sediment resuspension by feeding whales play only a role for biogeochemical cycling in the shallowest regions, along with other bottom-feeding mammals, which rarely face nutrient limitation. Whale falls are not essential to prevent species extinction in the deep-sea because their probability is so low that it may take 100 generations before deep-sea organism experience a whale fall. The all-over effect of the great whales as ecosystem engineers needs to be reconsidered for the different regions of the world ocean. Their impact as ecosystem engineers is far smaller than commonly portrayed in the literature.