Carbon isotope alteration during the thermal maturation of non-flowering plant species representative of those found within the geological record.

Rationale: The carbon isotope (δ C value) composition of fossil plant material is routinely used as a proxy of past climate and environment change. However, palaeoclimate interpretation requires assumptions about the stability of δ C values in plant material during its decomposition and incorporation into sediments. Previous work on modern angiosperm species shows δ C changes of several per mille during simulated decomposition experiments.

Sedimentary transport and fate of polycyclic aromatic hydrocarbons (PAH) from managed burning of moorland vegetation on a blanket peat, South Yorkshire, UK.

This study reports the concentrations of 18 polycyclic aromatic hydrocarbons (PAH) from managed burning of moorland vegetation and compares them to PAH in catchment vegetation, underlying peats, head water suspended sediment (HSS), stream water and reservoir sediment cores. Total PAH ranged from 203 to 11,112 μg/kg in the blanket peats, 101-290 μg/kg in the fresh moorland vegetation, 4186 μg/kg at the burnt site, 17,439 μg/kg in the HSS, 56 ng/L in the stream water and 987 to 7346 μg/kg in the reservoir sediments. No total or individual PAH concentrations exceeded the published sediment quality guidelines.

Evidence for bias in measured δ15N values of terrestrial and aquatic organic materials due to pre-analysis acid treatment methods.

We investigate the effect of acid treatment methods on δ(15)N values from a range of environmental organic materials in the context of the increased application of 'dual-mode' isotope analysis (the simultaneous measurement of δ(13)C and δ(15)N from the same acid-treated sample). Three common methods are compared; (i) untreated samples; (ii) acidification followed by sequential water rinse (rinse method); and (iii) acidification in silver capsules (capsule method). The influence of capsule type (silver and tin) on δ(15)N is also independently assessed (as the capsule and rinse methods combust samples in different capsules; silver and tin, respectively).