[MARMAM] New paper: δ15N Value Does Not Reflect Fasting in Mysticetes.

Joan Giménez Verdugo joan.gimenez at csic.es
Thu Apr 3 09:29:15 PDT 2014


We are pleased to announce the publication of the paper:


Aguilar A, Giménez J, Gómez–Campos E, Cardona L, Borrell A (2014) δ15N
Value Does Not Reflect Fasting in Mysticetes. PLoS ONE 9(3): e92288.
doi:10.1371/journal.pone.0092288


Abstract:

The finding that tissue δ15N values increase with protein catabolism has
led researchers to apply this value to gauge nutritive condition in
vertebrates. However, its application to marine mammals has in most
occasions failed. We investigated the relationship between δ15N values and
the fattening/fasting cycle in a model species, the fin whale, a migratory
capital breeder that experiences severe seasonal variation in body
condition. We analyzed two tissues providing complementary insights: one
with isotopic turnover (muscle) and one that keeps a permanent record of
variations in isotopic values (baleen plates). In both tissues δ15N values
increased with intensive feeding but decreased with fasting, thus
contradicting the pattern previously anticipated. The apparent
inconsistency during fasting is explained by the fact that a) individuals
migrate between different isotopic isoscapes, b) starvation may not trigger
significant negative nitrogen balance, and c) excretion drops and
elimination of 15N-depleted urine is minimized. Conversely, when intensive
feeding is resumed in the northern grounds, protein anabolism and excretion
start again, triggering 15N enrichment. It can be concluded that in whales
and other mammals that accrue massive depots of lipids as energetic
reserves and which have limited access to drinking water, the δ15N value is
not affected by fasting and therefore cannot be used as an indicatior of
nutritive condition.



A PDF copy of the work can be downloaded from:
http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0092288


Please do not hesitate to contact us for any question regarding our work.

Best regards,

Joan Gimenez

-- 
*Joan Giménez Verdugo*
PhD Student

*Estación Biológica de Doñana (CSIC)*
*Department of Conservation Biology*
Avenida Americo Vespucio s/n
41092 Sevilla
www.ebd.csic.es
 Mail: joan.gimenez at csic.es
Phone: +34619176849
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