Dear Colleagues,
Following our recent paper demonstrating that whales fertilise the ocean with
their nutrient-rich defecations (available free online:
http://rspb.royalsocietypublishing.org/content/early/2010/06/14/rspb.2010.0863),
we are pleased to announce a paper published today in PLoS showing that marine
mammals also defecate microbes which help to break down the nutrients
defecated, making them more bioavailable to the food chain.
Lavery TJ, Roudnew B, Seymour J, Mitchell JG, Jeffries T (2012) High Nutrient
Transport and Cycling Potential Revealed in the Microbial Metagenome of
Australian Sea Lion (Neophoca cinerea) Faeces. PLoS ONE 7(5): e36478.
doi:10.1371/journal.pone.0036478
Available free online:
(http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0036478)Abstract
Metagenomic analysis was used to examine the taxonomic diversity and metabolic
potential of an Australian sea lion (Neophoca cinerea) gut microbiome. Bacteria
comprised 98% of classifiable sequences and of these matches to Firmicutes
(80%) were dominant, with Proteobacteria and Actinobacteria representing 8% and
2% of matches respectively. The relative proportion of Firmicutes (80%) to
Bacteriodetes (2%) is similar to that in previous studies of obese humans and
obese mice, suggesting the gut microbiome may confer a predisposition towards
the excess body fat that is needed for thermoregulation within the cold oceanic
habitats foraged by Australian sea lions. Core metabolic functions, including
carbohydrate utilisation (14%), protein metabolism (9%) and DNA metabolism (7%)
dominated the metagenome, but in comparison to human and fish gut microbiomes
there was a significantly higher proportion of genes involved in phosphorus
metabolism (2.4%) and iron
scavenging mechanisms (1%). When sea lions defecate at sea, the relatively
high nutrient metabolism potential of bacteria in their faeces may accelerate
the dissolution of nutrients from faecal particles, enhancing their persistence
in the euphotic zone where they are available to stimulate marine production.
Kind thanks,
Dr. Trish Lavery
Flinders University.
Australia.
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