{"id":{"repo_id":"east-anglia","oai_identifier":"oai:ueaeprints.uea.ac.uk:52165"},"canonical_url":"https://search.dev.ndltd.org/etd/east-anglia/oai:ueaeprints.uea.ac.uk:52165","repository":{"repo_id":"east-anglia","name":"University of East Anglia","base_url":"https://ueaeprints.uea.ac.uk/cgi/oai2"},"display":{"title":"Environmental and biochemical controls on the molecular distribution and stable isotope composition of leaf wax biomarkers","abstract":"Leaf wax n-alkyl lipids are increasingly used as proxies in palaeoclimate studies. Palaeovegetation assemblages are reconstructed from their molecular distribution patterns, while their δ13C and δ2H signals are thought to reflect plant-environment interactions and palaeohydrological shifts, respectively. Such applications depend, however, upon these compounds faithfully recording environmental conditions. To explore the influence of environmental, physical and biochemical controls on n-alkane composition, leaf waxes from seven UK saltmarsh plants were analysed over two growing seasons. Linked analysis of sedimentary n-alkanes enabled further investigation of leaf wax biomarker integration into saltmarsh sediments. The molecular distribution and concentration of n-alkanes from the saltmarsh plants varied significantly. Bulk and n-alkane δ13C recorded different seasonal shifts, with a range of up to 13‰ in the offset between bulk and n-alkane 13C/12C values. This indicated that post-photosynthetic 13C/12C fractionation may be an important additional control on n-alkane δ13C signals. n-Alkane δ2H also varied among the sampled species by >100‰, and could not be explained by physical processes controlling the movement of water inside/outside and within leaves. Comparison with the 2H/1H of chloroplast-synthesised compounds (fatty acids, phytol) suggested these differences instead reflected the varied biochemical mechanisms operating in the chloroplast and cytosol. Sedimentary biomarker analysis further highlighted that small/moderate vegetation change could drive shifts of ~40‰ in sedimentary nalkane 2H/1H, while using globally averaged “typical” values to correct for fractionation between source water and n-alkane 2H/1H may not be representative of a specific geographical location. Results demonstrate: (i) the importance of biochemical mechanisms in controlling the molecular and isotopic composition of n-alkyl lipids; and (ii) the need to further constrain the influence of vegetation change on the isotope composition of sedimentary n-alkanes. Future research should address these areas in other biomes and depositional environments, to ensure accurate interpretation of modern and ancient leaf wax lipid data.","abstract_html":"Leaf wax n-alkyl lipids are increasingly used as proxies in palaeoclimate studies. Palaeovegetation assemblages are reconstructed from their molecular distribution patterns, while their δ13C and δ2H signals are thought to reflect plant-environment interactions and palaeohydrological shifts, respectively. Such applications depend, however, upon these compounds faithfully recording environmental conditions. To explore the influence of environmental, physical and biochemical controls on n-alkane composition, leaf waxes from seven UK saltmarsh plants were analysed over two growing seasons. Linked analysis of sedimentary n-alkanes enabled further investigation of leaf wax biomarker integration into saltmarsh sediments. The molecular distribution and concentration of n-alkanes from the saltmarsh plants varied significantly. Bulk and n-alkane δ13C recorded different seasonal shifts, with a range of up to 13‰ in the offset between bulk and n-alkane 13C/12C values. This indicated that post-photosynthetic 13C/12C fractionation may be an important additional control on n-alkane δ13C signals. n-Alkane δ2H also varied among the sampled species by >100‰, and could not be explained by physical processes controlling the movement of water inside/outside and within leaves. Comparison with the 2H/1H of chloroplast-synthesised compounds (fatty acids, phytol) suggested these differences instead reflected the varied biochemical mechanisms operating in the chloroplast and cytosol. Sedimentary biomarker analysis further highlighted that small/moderate vegetation change could drive shifts of ~40‰ in sedimentary nalkane 2H/1H, while using globally averaged “typical” values to correct for fractionation between source water and n-alkane 2H/1H may not be representative of a specific geographical location. Results demonstrate: (i) the importance of biochemical mechanisms in controlling the molecular and isotopic composition of n-alkyl lipids; and (ii) the need to further constrain the influence of vegetation change on the isotope composition of sedimentary n-alkanes. Future research should address these areas in other biomes and depositional environments, to ensure accurate interpretation of modern and ancient leaf wax lipid data.","abstract_has_math":false,"creators":["Eley, Yvette"],"institution":"University of East Anglia","degree_name":"phd","degree_level":"doctoral","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2014,"date_issued":"2014-06","date_published":"2014-06","updated_at":"2026-07-24T02:12:06Z","subjects":[],"languages":["en"],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Eley, Yvette"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2014-06"]},{"key":"dc:date.issued","label":"Date","values":["2014-06"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["School of Environmental Sciences"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of East Anglia"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["https://ueaeprints.uea.ac.uk/id/eprint/52165/"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["doctoral"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["phd"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:language","label":"Dc Language","values":["en"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://ueaeprints.uea.ac.uk/id/eprint/52165/1/Yvette_Eley_2014.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Leaf wax n-alkyl lipids are increasingly used as proxies in palaeoclimate studies. Palaeovegetation assemblages are reconstructed from their molecular distribution patterns, while their δ13C and δ2H signals are thought to reflect plant-environment interactions and palaeohydrological shifts, respectively. Such applications depend, however, upon these compounds faithfully recording environmental conditions. To explore the influence of environmental, physical and biochemical controls on n-alkane composition, leaf waxes from seven UK saltmarsh plants were analysed over two growing seasons. Linked analysis of sedimentary n-alkanes enabled further investigation of leaf wax biomarker integration into saltmarsh sediments. The molecular distribution and concentration of n-alkanes from the saltmarsh plants varied significantly. Bulk and n-alkane δ13C recorded different seasonal shifts, with a range of up to 13‰ in the offset between bulk and n-alkane 13C/12C values. This indicated that post-photosynthetic 13C/12C fractionation may be an important additional control on n-alkane δ13C signals. n-Alkane δ2H also varied among the sampled species by >100‰, and could not be explained by physical processes controlling the movement of water inside/outside and within leaves. Comparison with the 2H/1H of chloroplast-synthesised compounds (fatty acids, phytol) suggested these differences instead reflected the varied biochemical mechanisms operating in the chloroplast and cytosol. Sedimentary biomarker analysis further highlighted that small/moderate vegetation change could drive shifts of ~40‰ in sedimentary nalkane 2H/1H, while using globally averaged “typical” values to correct for fractionation between source water and n-alkane 2H/1H may not be representative of a specific geographical location. Results demonstrate: (i) the importance of biochemical mechanisms in controlling the molecular and isotopic composition of n-alkyl lipids; and (ii) the need to further constrain the influence of vegetation change on the isotope composition of sedimentary n-alkanes. Future research should address these areas in other biomes and depositional environments, to ensure accurate interpretation of modern and ancient leaf wax lipid data."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Environmental and biochemical controls on the molecular distribution and stable isotope composition of leaf wax biomarkers"]}]}],"canonical_facts":{"dc:creator":["Eley, Yvette"],"dc:date":["2014-06"],"dc:date.issued":["2014-06"],"dc:description.abstract":["Leaf wax n-alkyl lipids are increasingly used as proxies in palaeoclimate studies. Palaeovegetation assemblages are reconstructed from their molecular distribution patterns, while their δ13C and δ2H signals are thought to reflect plant-environment interactions and palaeohydrological shifts, respectively. Such applications depend, however, upon these compounds faithfully recording environmental conditions. To explore the influence of environmental, physical and biochemical controls on n-alkane composition, leaf waxes from seven UK saltmarsh plants were analysed over two growing seasons. Linked analysis of sedimentary n-alkanes enabled further investigation of leaf wax biomarker integration into saltmarsh sediments. The molecular distribution and concentration of n-alkanes from the saltmarsh plants varied significantly. Bulk and n-alkane δ13C recorded different seasonal shifts, with a range of up to 13‰ in the offset between bulk and n-alkane 13C/12C values. This indicated that post-photosynthetic 13C/12C fractionation may be an important additional control on n-alkane δ13C signals. n-Alkane δ2H also varied among the sampled species by >100‰, and could not be explained by physical processes controlling the movement of water inside/outside and within leaves. Comparison with the 2H/1H of chloroplast-synthesised compounds (fatty acids, phytol) suggested these differences instead reflected the varied biochemical mechanisms operating in the chloroplast and cytosol. Sedimentary biomarker analysis further highlighted that small/moderate vegetation change could drive shifts of ~40‰ in sedimentary nalkane 2H/1H, while using globally averaged “typical” values to correct for fractionation between source water and n-alkane 2H/1H may not be representative of a specific geographical location. Results demonstrate: (i) the importance of biochemical mechanisms in controlling the molecular and isotopic composition of n-alkyl lipids; and (ii) the need to further constrain the influence of vegetation change on the isotope composition of sedimentary n-alkanes. Future research should address these areas in other biomes and depositional environments, to ensure accurate interpretation of modern and ancient leaf wax lipid data."],"dc:format":["application/pdf"],"dc:identifier.uri":["https://ueaeprints.uea.ac.uk/id/eprint/52165/1/Yvette_Eley_2014.pdf"],"dc:language":["en"],"dc:publisher.department":["School of Environmental Sciences"],"dc:publisher.institution":["University of East Anglia"],"dc:relation.isreferencedby":["https://ueaeprints.uea.ac.uk/id/eprint/52165/"],"dc:title":["Environmental and biochemical controls on the molecular distribution and stable isotope composition of leaf wax biomarkers"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["doctoral"],"dc:type.qualificationname":["phd"]},"updated_at":"2026-07-24T02:12:06Z"}