The carbon isotopic composition (δ¹³C) of selected specific biomarkers provides important information on the relationship between plant species and the environment in which they developed. Here we present baseline data of δ¹³C values of individual n-alkanes (δ¹³C_n-alkanes) from leaf waxes of mangrove species – Avicennia spp., Rhizophora mangle and Laguncularia racemosa – typical of mangrove forests collected from equatorial to sub-tropical regions in Brazil. The objective was to evaluate the influence of tree physiology, local hydrology and climatic factors upon the molecular and isotopic signature of the leaf wax n-alkanes. Total n-alkanes concentration, average chain length (ACL_25-35) and carbon preference index (CPI_24-36) are higher for Avicennia spp. contrasting with the lower values found for R. mangle and L. racemosa. This seems to derive from the physiological characteristics of each species with respect to the intrinsic water use efficiency under the specific tidal flooding regime of mangrove forests. For Avicennia spp. inverse correlations between δ¹³C_n-alkanes values (δ¹³C₂₇, δ¹³C₂₉, δ¹³C₃₁, δ¹³C₃₃ and δ¹³C_WA) and mean annual precipitation suggests plant response to local environmental conditions. For R. mangle species, relationships between ACL_25-35 and mean annual potential evapotranspiration, and between CPI_24-36 and mean annual temperature were observed. These results indicate that δ¹³C_n-alkanes values in Avicennia spp. as well as ACL_25-35 and CPI_24-36 in R. mangle may be useful in tracing environmental changes and, as long as preservation of reliable record in sediments is verified, may also be applied in the reconstruction of past environmental conditions. The different molecular and isotopic footprints of the mangrove species presented here have potential in future interpretations of n-alkanes as biomarkers in biogeochemical studies in mangrove-dominated coastal regions.

选定的特定生物标志物的碳同位素组成 (δ ¹³ C) 提供了关于植物物种与其发育环境之间关系的重要信息。在这里，我们提供了来自红树林物种叶蜡的单个正烷烃（δ ¹³ C _{n -烷烃}）的 δ ¹³ C 值的基线数据- Avicennia spp.、Rhizophora mangle和Laguncularia racemosa - 从赤道到_亚热带收集的典型红树林巴西的热带地区。目的是评估树木生理学、当地水文和气候因素对叶蜡分子和同位素特征的影响正构烷烃。Avicennia spp 的总正烷烃浓度、平均链长 (ACL _25-35 ) 和碳偏好指数 (CPI _24-36 ) 较高。与R. mangle和L. racemosa的较低值形成对比。这似乎源于每个物种在红树林特定潮汐洪水情况下固有水分利用效率的生理特征。对于Avicennia spp。δ ¹³ C _{n -烷烃}值（δ ¹³ C ₂₇、δ ¹³ C ₂₉, δ ¹³ C ₃₁ , δ ¹³ C ₃₃和 δ ¹³ C _WA ) 和年平均降水量表明植物对当地环境条件的反应。对于R. mangle物种，观察到ACL _25-35与年平均潜在蒸散量之间以及 CPI _24-36与年平均温度之间的关系。这些结果表明 δ ¹³ C _{n -烷烃}值在Avicennia spp。以及ACL _25-35和CPI _24-36在R.碾压机可用于追踪环境变化，只要证实了沉积物中可靠记录的保存，也可用于重建过去的环境条件。这里介绍的红树林物种的不同分子和同位素足迹有可能在未来将正烷烃解释为红树林为主的沿海地区生物地球化学研究中的生物标志物。