Chemical composition of volatile and extractive compounds of pine and spruce leaf litter in the initial stages of decomposition

V. A. Isidorov,A. Purzyńska-Pugacewicz,Z. Tyszkiewicz,M. Smolewska

doi:10.5194/bg-7-2785-2010

V. A. Isidorov, A. Purzyńska-Pugacewicz + Show 2 more

Open Access

https://doi.org/10.5194/bg-7-2785-2010

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Abstract

Abstract. A litter bag experiment was conducted to analyze changes in chemical composition in Scots pine (Pinus sylvestris) and Norway spruce (Picea abies) needle litter in the first stages of decomposition in natural conditions. The emission rates of monoterpenes and concentration of extractive secondary metabolites were determined five times over a 16-month period. It has been shown that pine and spruce needle litter in the first stages of decomposition (up to 165 days) emits monoterpene hydrocarbons into the gas phase with the rates comparable to those in emissions from live needles of these trees. This suggests that leaf litter is an important source of atmospheric terpenes. It has also been proved that the litter contains considerable amounts of non-volatile substances that can be precursors of oxidized volatile compounds formed as a result of enzymatic reactions. Non-volatile but water soluble secondary metabolites of the leaf litter may be involved in nutrient cycling and have an influence on soil community.

Highlights

Biogenic reactive volatile organic compounds (VOCs) have been attracting attention of atmospheric chemists mainly in relation with the estimation of biogenic contributions to the atmospheric carbon budget, as well as with the problems of tropospheric ozone and aerosol particles production
With the two analyzed within this study types of leaf litter the data set is too small to estimate reliably the scale of either VOCs emission or migration of water-soluble organics into the soil, some preliminary notes can be made: 1. The entirety of the presented data proves that decomposed Scots pine and Norway spruce litter can emit volatile terpenes into the gas phase with the rates comparable to the emission rates of living needle leafs only in the first stages of decomposition
Taking into account the constant inflow and renovation of the leaf litter, it can be supposed that the forest floor is an important source of atmospheric terpenes

Summary

Introduction

Biogenic reactive volatile organic compounds (VOCs) have been attracting attention of atmospheric chemists mainly in relation with the estimation of biogenic contributions to the atmospheric carbon budget, as well as with the problems of tropospheric ozone and aerosol particles production. A potential source of atmospheric VOCs that is often ignored is leaf litter, and dry deposition of VOCs to the earth surface is another process that is often underestimated. Both of these problems have been attracting some attention in the last decades, but neither has been sufficiently well studied. In the volatile emissions of litter of seven species of deciduous and coniferous trees 14 monoterpenes and more than 60 organic compounds of other classes were identified (Isidorov and Janova, 2002; Isidorov et al, 2003)

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