a b s t r a c tThe Fukushima Daiichi Nuclear Power Plant (FDNPP) accident resulted in radiocesium fallout contaminating coastal catchments of the Fukushima Prefecture. As the decontamination effort progresses, the potential downstream migration of radiocesium contaminated particulate matter from forests, which cover over 65% of the most contaminated region, requires investigation. Carbon and nitrogen elemental concentrations and stable isotope ratios are thus used to model the relative contributions of forest, cultivated and subsoil sources to deposited particulate matter in three contaminated coastal catchments. Samples were taken from the main identified sources: cultivated (n ¼ 28), forest (n ¼ 46), and subsoils (n ¼ 25). Deposited particulate matter (n ¼ 82) was sampled during four fieldwork campaigns from November 2012 to November 2014. A distribution modelling approach quantified relative source contributions with multiple combinations of element parameters (carbon only, nitrogen only, and four parameters) for two particle size fractions (<63 mm and <2 mm). Although there was significant particle size enrichment for the particulate matter parameters, these differences only resulted in a 6% (SD 3%) mean difference in relative source contributions. Further, the three different modelling approaches only resulted in a 4% (SD 3%) difference between relative source contributions. For each particulate matter sample, six models (i.e. <63 mm and <2 mm from the three modelling approaches) were used to incorporate a broader definition of potential uncertainty into model results. Forest sources were modelled to contribute 17% (SD 10%) of particulate matter indicating they present a long term potential source of radiocesium contaminated material in fallout impacted catchments. Subsoils contributed 45% (SD 26%) of particulate matter and cultivated sources contributed 38% (SD 19%). The reservoir of radiocesium in forested landscapes in the Fukushima region represents a potential long-term source of particulate contaminated matter that will require diligent management for the foreseeable future.

The Eocene-Oligocene transition (EOT,~34 Ma) is the largest global cooling of the Cenozoic Era and led the Earth's climatic system to change from a greenhouse to an icehouse mode. Although it is well documented in marine settings, the few studies focusing on continental environments have demonstrated regional heterogeneities. The study core CDB1, located in the Rennes Basin (Western France), is a unique terrestrial (lacustrine-palustrine) record comprising well-preserved and terrestrial-derived organic-rich sediments encompassing the EOT. Clay minerals and the first organic nitrogen isotope record (d 15 N org ) of terrestrial origin for this period are used to reconstruct palaeoclimate changes across this key interval. As suggested in worldwide marine and a few continental records, a stepwise transition from warm/humid conditions in the Late Eocene to cooler/drier conditions in the Early Oligocene is confirmed in the area. In addition, an episode of drier conditions in the Late Eocene and humid/dry cycles in the Early Oligocene are suggested.

Earthworms are known to have a major impact on organic matter dynamics in soils. The precise dynamics of carbon incorporation and/or decomposition in soil under the influence of earthworms still need to be investigated. In a mesocosm experiment, the fate of Ryegrass root and shoot litter was monitored in the soil, in the presence and absence of anecic earthworms Lumbricus terrestris L. Residues were 13 C labelled and deposited onto the soil surface. Incorporation of 13 C in surface casts and in the 0-20 and 40-60 cm soil layers was monitored 1, 2, 4, 8, 24 and 54 weeks after adding labelled litter. Organic carbon content and δ 13 C values were obtained for all samples, allowing the determination of the percentage of carbon derived from labelled litter (Clab). Roots and shoots were incorporated in the 0-20 cm soil layer during the year of experiment, Clab reaching 11.4 % of the soil organic carbon after 54 weeks. On the contrary, no significant contribution from labelled residues was observed in the 40-60 cm layer. Roots decomposed at a slower rate compared to shoots. Litter incorporation was observed in casts from the very first weeks of experiment (Clab from 34.8 to 51.4 % after 2 weeks). In the soil, a significant effect of earthworms on the Clab was detected after 24 weeks. Earthworms accelerated root and shoot decomposition in the soil. They also enhanced, in the presence of shoot residues, the decomposition of the organic matter originally present in the soil. However, after one year, earthworms smoothed the difference between residue types in casts and to a lesser extent in soil, revealing their capacity to enhance the decomposition of both roots and shoots.