@article{HoffmannKahmenCernusaketal.2013,
  author    = {Hoffmann, Bernd and Kahmen, Ansgar and Cernusak, Lucas A. and Arndt, Stefan K. and Sachse, Dirk},
  title     = {Abundance and distribution of leaf wax n-alkanes in leaves of Acacia and Eucalyptus trees along a strong humidity gradient in northern Australia},
  series = {Organic geochemistry : the international journal for rapid publication of current research in organic geochemistry and biochemistry},
  volume    = {62},
  journal   = {Organic geochemistry : the international journal for rapid publication of current research in organic geochemistry and biochemistry},
  number    = {9},
  publisher = {Elsevier},
  address   = {Oxford},
  issn      = {0146-6380},
  doi       = {10.1016/j.orggeochem.2013.07.003},
  pages     = {62 -- 67},
  year      = {2013},
  abstract  = {Environmental parameters such as rainfall, temperature and relative humidity can affect the composition of higher plant leaf wax. The abundance and distribution of leaf wax biomarkers, such as long chain n-alkanes, in sedimentary archives have therefore been proposed as proxies reflecting climate change. However, a robust palaeoclimatic interpretation requires a thorough understanding of how environmental changes affect leaf wax n-alkane distributions in living plants. We have analysed the concentration and chain length distribution of leaf wax n-alkanes in Acacia and Eucalyptus species along a 1500 km climatic gradient in northern Australia that ranges from subtropical to arid. We show that aridity affected the concentration and distribution of n-alkanes for plants in both genera. For both Acacia and Eucalyptus n-alkane concentration increased by a factor of ten to the dry centre of Australia, reflecting the purpose of the wax in preventing water loss from the leaf. Furthermore, Acacian-alkanes decreased in average chain length (ACL) towards the arid centre of Australia, whereas Eucalyptus ACL increased under arid conditions. Our observations demonstrate that n-alkane concentration and distribution in leaf wax are sensitive to hydroclimatic conditions. These parameters could therefore potentially be employed in palaeorecords to estimate past environmental change. However, our finding of a distinct response of n-alkane ACL values to hydrological changes in different taxa also implies that the often assumed increase in ACL under drier conditions is not a robust feature for all plant species and genera and as such additional information about the prevalent vegetation are required when ACL values are used as a palaeoclimate proxy.},
  language  = {en}
}