Unexpected shifts in fatty acid composition in response to diet in a common littoral amphipod

To determine whether fatty acid (FA) profilesare a useful biomarker to trace the flow of materialin a coastal food web, we fed the sandhopper Bellor -chestia quoyana specific seaweed diets, each with acontrasting FA profile including Durvillaea antarctica(Phaeophyta), Ecklonia radiata (Phaeophyta) o...

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Bibliographic Details
Published in:Marine Ecology Progress Series
Main Authors: McLeod, RJ, Hyndes, GA, Hurd, CL, Frew, RD
Format: Article in Journal/Newspaper
Language:English
Published: Inter-Research 2013
Subjects:
Environmental Sciences
Ecological Applications
Ecological Impacts of Climate Change
Antarc*
Antarctica
Online Access:https://doi.org/10.3354/meps10327
http://ecite.utas.edu.au/89076
Description
Summary:To determine whether fatty acid (FA) profilesare a useful biomarker to trace the flow of materialin a coastal food web, we fed the sandhopper Bellor -chestia quoyana specific seaweed diets, each with acontrasting FA profile including Durvillaea antarctica(Phaeophyta), Ecklonia radiata (Phaeophyta) or Ulvasp. (Chlorophyta). We then compared changes in FAcomposition in relation to diet for this sandhopper. After12 d, sandhoppers from each treatment had distinct FAprofiles, particularly with respect to polyunsaturatedFAs (PUFAs); however, increases in specific FAs did notrelate to those FAs that were abundant in their diet. Forexample, sandhoppers fed PUFA-deficient Ulva sp. exhibiteda relative increase in PUFAs. The E. radiata andUlva sp. diets both caused significant shifts in sandhopperFA composition over the course of the experiment.In order to follow the assimilation of carbon and FAs,sandhoppers were fed natural or 13C-enhanced E. radiataor Ulva sp., and changes to the δ13C of individualFAs were measured over time. Turnover of the mostabundant FAs, 16:0 and 18:1ω9, was higher for sandhoppersfed E. radiata than for those fed Ulva sp. Comparisonsbetween bulk tissue δ13C and δ13C of individualFAs were consistent with sandhoppers modifying theturnover rate of FA in response to diet. These findingssuggest that there is no consistent relationship betweenthe FA compositions of green and brown seaweeds andthat of the sandhopper B. quoyana. We caution thatcommunity-level application of FAs as a dietary biomarkertool must be accompanied by controlled experimentsincorporating key species of relevance.

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