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Article: Evidence for bias in C and N concentrations and δ 13C composition of terrestrial and aquatic organic materials due to pre-analysis acid preparation methods

TitleEvidence for bias in C and N concentrations and δ 13C composition of terrestrial and aquatic organic materials due to pre-analysis acid preparation methods
Authors
Keywordsδ 13C
Acid Treatment
C/N ratio
Environmental Reconstruction
Method Comparison
Organic Matter
Issue Date2011
PublisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/chemgeo
Citation
Chemical Geology, 2011, v. 282 n. 3-4, p. 67-83 How to Cite?
AbstractThis study is the first systematic comparison of the effect of acid treatment methods on the reliability of organic carbon [C] and nitrogen [N], and carbon isotope (δ 13C) values on a range of terrestrial and aquatic, modern and geological environmental materials. We investigated the 3 most common methods; (i) acidification followed by sequential deionised water rinses ("rinse method"); (ii) acidification in silver capsules ("capsule method"); and (iii) acidification by exposure to an acid vapour ("fumigation method"). We also investigated the effect of sample size and capsule type (silver and tin) on C/N ratio and δ 13C values. We find (i) that %C, %N, C/N and δ 13C showed significant within and between method variability; (ii) disproportionate and non-linear offsets of %C, %N and C/N values after acidification within and between methods and within and between sample materials; (iii) that alterations in %C did not necessarily manifest themselves in shifts in δ 13C, and vice-versa; (iv) that small (~90-gC) sample sizes showed consistent overestimations and inaccuracies after acidification; (v) that the effect of capsule type was not significant on most samples, but did show a notable effect on our aquatic materials, generally increasing %C and %N, and producing depleted δ 13C values. These findings raise cause for concern on the interpretative nature of C/N ratios and their support for carbon isotope values. The comparability between laboratories (different preparation methods) and environmental settings (amount, type and nature of OM) is also likely to be problematic. We conclude that the response of C and N concentrations in organic matter to acid treatment in environmental materials is neither negligible nor systematic. © 2011 Elsevier B.V.
Persistent Identifierhttp://hdl.handle.net/10722/134399
ISSN
2015 Impact Factor: 3.482
2015 SCImago Journal Rankings: 2.346
ISI Accession Number ID
Funding AgencyGrant Number
NERCNE/F007264/1
Funding Information:

CRB acknowledges financial support from the NERC through PhD studentship NE/F007264/1. We thank Dr. Tim Heaton (NIGL) and Dr. Chris Vane (BGS) for discussion of results and comments on earlier drafts of the manuscript. CRB dedicates this manuscript to his late grandmother, Jane Simpson (1935-2010).

References

 

DC FieldValueLanguage
dc.contributor.authorBrodie, CRen_HK
dc.contributor.authorLeng, MJen_HK
dc.contributor.authorCasford, JSLen_HK
dc.contributor.authorKendrick, CPen_HK
dc.contributor.authorLloyd, JMen_HK
dc.contributor.authorYongqiang, Zen_HK
dc.contributor.authorBird, MIen_HK
dc.date.accessioned2011-06-17T09:19:29Z-
dc.date.available2011-06-17T09:19:29Z-
dc.date.issued2011en_HK
dc.identifier.citationChemical Geology, 2011, v. 282 n. 3-4, p. 67-83en_HK
dc.identifier.issn0009-2541en_HK
dc.identifier.urihttp://hdl.handle.net/10722/134399-
dc.description.abstractThis study is the first systematic comparison of the effect of acid treatment methods on the reliability of organic carbon [C] and nitrogen [N], and carbon isotope (δ 13C) values on a range of terrestrial and aquatic, modern and geological environmental materials. We investigated the 3 most common methods; (i) acidification followed by sequential deionised water rinses ("rinse method"); (ii) acidification in silver capsules ("capsule method"); and (iii) acidification by exposure to an acid vapour ("fumigation method"). We also investigated the effect of sample size and capsule type (silver and tin) on C/N ratio and δ 13C values. We find (i) that %C, %N, C/N and δ 13C showed significant within and between method variability; (ii) disproportionate and non-linear offsets of %C, %N and C/N values after acidification within and between methods and within and between sample materials; (iii) that alterations in %C did not necessarily manifest themselves in shifts in δ 13C, and vice-versa; (iv) that small (~90-gC) sample sizes showed consistent overestimations and inaccuracies after acidification; (v) that the effect of capsule type was not significant on most samples, but did show a notable effect on our aquatic materials, generally increasing %C and %N, and producing depleted δ 13C values. These findings raise cause for concern on the interpretative nature of C/N ratios and their support for carbon isotope values. The comparability between laboratories (different preparation methods) and environmental settings (amount, type and nature of OM) is also likely to be problematic. We conclude that the response of C and N concentrations in organic matter to acid treatment in environmental materials is neither negligible nor systematic. © 2011 Elsevier B.V.en_HK
dc.languageengen_US
dc.publisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/chemgeoen_HK
dc.relation.ispartofChemical Geologyen_HK
dc.subjectδ 13Cen_HK
dc.subjectAcid Treatmenten_HK
dc.subjectC/N ratioen_HK
dc.subjectEnvironmental Reconstructionen_HK
dc.subjectMethod Comparisonen_HK
dc.subjectOrganic Matteren_HK
dc.titleEvidence for bias in C and N concentrations and δ 13C composition of terrestrial and aquatic organic materials due to pre-analysis acid preparation methodsen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=0009-2541&volume=282&issue=3-4&spage=67&epage=83&date=2011&atitle=Evidence+for+bias+in+C+and+N+concentrations+and+δ13C+composition+of+terrestrial+and+aquatic+organic+materials+due+to+pre-analysis+acid+preparation+methods-
dc.identifier.emailYongqiang, Z:yqzong@hkucc.hku.hken_HK
dc.identifier.authorityYongqiang, Z=rp00846en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1016/j.chemgeo.2011.01.007en_HK
dc.identifier.scopuseid_2-s2.0-79952103739en_HK
dc.identifier.hkuros185809en_US
dc.identifier.hkuros185696en_US
dc.identifier.hkuros198438en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-79952103739&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume282en_HK
dc.identifier.issue3-4en_HK
dc.identifier.spage67en_HK
dc.identifier.epage83en_HK
dc.identifier.isiWOS:000289172400001-
dc.publisher.placeNetherlandsen_HK
dc.identifier.scopusauthoridBrodie, CR=36917954200en_HK
dc.identifier.scopusauthoridLeng, MJ=7006497331en_HK
dc.identifier.scopusauthoridCasford, JSL=6505849496en_HK
dc.identifier.scopusauthoridKendrick, CP=35210597000en_HK
dc.identifier.scopusauthoridLloyd, JM=7402365382en_HK
dc.identifier.scopusauthoridYongqiang, Z=7005203454en_HK
dc.identifier.scopusauthoridBird, MI=7102578362en_HK
dc.identifier.citeulike8671468-

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