Can whales mix the ocean? - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Biogeosciences Discussions Année : 2012

Can whales mix the ocean?

Tj Lavery
  • Fonction : Auteur
B. Roudnew
  • Fonction : Auteur
Jg Mitchell
  • Fonction : Auteur
J. Middleton
  • Fonction : Auteur

Résumé

Ocean mixing influences global climate and enhances primary productivity by transporting nutrient rich water into the euphotic zone. The contribution of the swimming biosphere to diapycnal mixing in the ocean has been hypothesised to occur on scales similar to that of tides or winds, however, the extent to which this contributes to nutrient transport and stimulates primary productivity has not been explored. Here, we introduce a novel method to estimate the diapycnal diffusivity that occurs as a result of a sperm whale swimming through a pycnocline. Nutrient profiles from the Hawaiian Ocean are used to further estimate the amount of nitrogen transported into the euphotic zone and the primary productivity stimulated as a result. We estimate that the 80 sperm whales that travel through an area of 104 km2 surrounding Hawaii increase diapycnal diffusivity by 10-6 m2 s−1 which results in the flux of 105 kg of nitrogen into the euphotic zone each year. This nitrogen input subsequently stimulates 6 × 105 kg of carbon per year. The nutrient input of swimming sperm whales is modest compared to dominant modes of nutrient transport such as nitrogen fixation but occurs more consistently and thus may provide the nutrients necessary to enable phytoplankton growth and survival in the absence of other seasonal and daily nutrient inputs.

Domaines

Océanographie

Dates et versions

hal-00823541 , version 1 (17-05-2013)

Identifiants

Citer

Tj Lavery, B. Roudnew, Laurent Seuront, Jg Mitchell, J. Middleton. Can whales mix the ocean?. Biogeosciences Discussions, 2012, 9, pp.8387-8403. ⟨10.5194/bgd-9-8387-2012⟩. ⟨hal-00823541⟩
64 Consultations
0 Téléchargements

Altmetric

Partager

Gmail Mastodon Facebook X LinkedIn More