Effect of acidification on elemental and isotopic compositions of sediment organic matter and macro‐invertebrate muscle tissues in food web research |
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Authors: | Debashish Mazumder Jordan Iles Jeff Kelleway Tsuyoshi Kobayashi Lisa Knowles Neil Saintilan Suzanne Hollins |
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Institution: | 1. Australian Nuclear Science and Technology Organisation, Locked Bag 2001 Kirrawee DC, NSW 2232, Australia;2. NSW Department of Environment, Climate Change and Water, PO Box A290, Sydney South, NSW 1232, Australia |
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Abstract: | Stable isotope techniques in food web studies often focus on organic carbon in food sources which are subsequently assimilated in the tissue of consumer organisms through diet. The presence of non‐dietary carbonates in bulk samples can affect their δ13C values, altering how their results are interpreted. Acidification of samples is a common practice to eliminate any inorganic carbon present prior to analysis. We examined the effects of pre‐analysis acidification on two size fractions of sediment organic matter (SOM) from marine and freshwater wetlands and pure muscle tissue of a common freshwater invertebrate (Cherax destructor). The elemental content and isotopic ratios of carbon and nitrogen were compared between paired samples of acidified and control treatments. Our results showed that acidification does not affect the elemental or isotopic values of freshwater SOM. In the marine environment acidification depleted the δ13C and δ15N values of the fine fraction of saltmarsh and δ15N values of mangrove fine SOM. Whilst acidification did not change the elemental content of invertebrate muscle tissue, the δ13C and δ15N values were affected. We recommend to researchers considering using acidification techniques on material prepared for stable isotope analysis that a formal assessment of the effect of acidification on their particular sample type should be undertaken. Further detailed investigation to understand the impact of acidification on elemental and isotopic values of organic matter and muscular tissues is required. Copyright © 2010 John Wiley & Sons, Ltd. |
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