Science of the Total Environment 324 (2004) 91–103 0048-9697/04/$ - see front matter  2003 Elsevier B.V. All rights reserved. doi:10.1016/j.scitotenv.2003.10.020 Biomarker signature in tropical wetland: lignin phenol vegetation index (LPVI) and its implications for reconstructing the paleoenvironment Shafi M. Tareq *, Noriyuki Tanaka , Keiichi Ohta a,b, c d,e Division of Earth and Environmental Sciences, Graduate School of Environmental Studies, Nagoya University, Furo-cho, a Chikusa-ku, Nagoya 464-8601, Japan Department of Environmental Science, Jahangirnagar University, Dhaka 1342, Bangladesh b Frontier Research System for Global Change, International Arctic Research Center, University of Alaska, Fairbanks, AK, USA c Hydrospheric Atmospheric Research Center, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8601, Japan d School of Environmental Science, The University of Shiga Prefecture, 2500 Hassaka-cho, Hikone, Shiga 522-8533, Japan e Accepted 16 October 2003 Abstract Organic matter of a peat core (3.60 m, 7428 years BP) collected from Rawa Danau, west Java, Indonesia, was analyzed to evaluate the early diagenetic fates of lignin in a tropical wetland and to reconstruct past vegetation and climate changes. Vertical profiles of (AdyAl)v, (AdyAl)s, and l show that the lignin composition is well preserved 8 in a sub-aqueous environment under reducing conditions. The sedimentary terrigenous plant material at Rawa Danau is comprised predominantly of angiosperm wood. For this kind of tropical, diverse, and dynamic ecosystem, a new vegetation change index called lignin phenol vegetation index (LPVI): LPVI is defined using the lignin phenol composition. This index can sensitively detect terrestrial vegetation changes as well as environmental conditions forcing such changes. The LPVI of the Rawa Danau peat core provides better resolution than other lignin parameters used previously, and reveals four major vegetation change events since the mid–late Holocene. In comparison to other geochemical data (i.e. elemental carbon, isotopes, and hydrocarbons), the LPVI is more sensitive and is able to trace even minor vegetation and climate changes and thus could improve biogeochemical interpretations of peat records.  2003 Elsevier B.V. All rights reserved. Keywords: Biomarker; Lignin; LPVI; Vegetation; Paleoenvironment; Tropical area 1. Introduction The interest in identify past environmental var- iations is increasing, thus enhancing the prospect of developing more reliable and accurate methods *Corresponding author. Tel.: q81-52-789-3475; fax: q81- 52-789-3436. E-mail address: smtareq@juniv.edu, smtareq@yahoo.com (S.M. Tareq). for identifying past environment changes (Aaby, 1976; Meyers, 1997; Kuder and Kruge, 1998; Pendall et al., 2001). The study of pollen, diatoms, isotopes or biomarkers in lake sediments has become the standard means of investigating local paleovegetation and paleoclimates (Ertel et al., 1984; Prahl et al., 1994; Meyers, 1994; Orem et al., 1997; Kuder and Kruge, 1998; Hu et al., 1999; Filley et al., 2001; Kaars et al., 2001; Anshari et