[MARMAM] New publication: sperm whales export carbon in the Southern Ocean

Trish Lavery tricia_lavery at yahoo.com.au
Wed Nov 24 14:18:00 PST 2010


Dear colleagues,
We are pleased to announce a new paper published recently in Proceedings of the 
Royal Society of Biology B:
Lavery TJ, Roudnew, B, Gill P, Seymour J, Seuront L, Johnson G, Mitchell JG, 
Smetacek V. 2010. Iron defecation by sperm whales stimulates carbon 

export in the Southern Ocean. Proceedings of the Royal Society of Biology B, 
277, 3527-3531.
A PDF is available free online 'Sperm whales export carbon' or upon request to 
Trish.Lavery at flinders.edu.au.
 
ABSTRACT  
The iron-limited Southern Ocean plays an important role in regulating 
atmospheric CO2 levels. Marine mammal respiration has been proposed to decrease 
the efficiency of the Southern Ocean biological pump by returning 
photosynthetically fixed carbon to the atmosphere. Here, we show that by 
consuming prey at depth and defecating iron-rich liquid faeces into the photic 
zone, sperm whales (Physeter macrocephalus) instead stimulate new primary 
production and carbon export to the deep ocean. We estimate that Southern Ocean 
sperm whales defecate 50 tonnes of iron into the photic zone each year. Molar 
ratios of Cexport : Feadded determined during natural ocean fertilization events 
are used to estimate the amount of carbon exported to the deep ocean in response 
to the iron defecated by sperm whales. We find that Southern Ocean sperm whales 
stimulate the export of 4 × 105 tonnes of carbon per year to the deep ocean and 
respire only 2 × 105 tonnes of carbon per year. By enhancing new primary 
production, the populations of 12 000 sperm whales in the Southern Ocean act as 
a carbon sink, removing 2 × 105 tonnes more carbon from the atmosphere than they 
add during respiration. The ability of the Southern Ocean to act as a carbon 
sink may have been diminished by large-scale removal of sperm whales during 
industrial whaling. 
 
Kindest thanks for your interest, 
Trish J Lavery
PhD candidate
Flinders University
Trish.Lavery at flinders.edu.au
http://www.scieng.flinders.edu.au/current/biology/msl/mswebsite_ppl_lavery.htm


      
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