Distribution of soluble heavy metal concentrations in natural acid soils at depths under tropical, sub-tropical and temperate forests of China

Climatic conditions such as temperate and rainfall, the types of soils and vegetations may affect the biogeochemical behaviour of heavy metals in natural acid forest soils, which in turn affects soil biological process. However, to date our knowledge is l…     

Variations of nutrient element contents of plants and soils in the process of karst rocky desertification

The present research on karst rocky desertification is mainly focused on qualitative analysis and obviously lack of quantitative and successive mechanism studies. Currently, classification of rocky desertification grades mainly depends on ratio of rocky coverage or ratio of plant and soil coverage. The process of rocky desertification was divided into latent, slight, medium and serious grades without mention of soil degradation. The Cha＇eryan catchment in the Huajiang Gorge of Guizhou Province was selected as the research area in this paper. Soil basic physical characteristics, nutrient element contents of soil and plant were studied in the process of rocky desertification. The karst soil characteristics elucidated that the clay content was high, the contents of soil organic matter, nutrient element （except potassium and sodium）, available contents of elements （except of potassium） were also high; ashes of plants were rich in calcium and nitrogen, and poor in iron, zinc, potassium and phosphorus. Meanwhile, the contents of plant ashes showed a significant positive relationship with calcium content of plant. There were no clear relations between soil degradation and succession of rocky desertification according to current classification standard. Soil particle size distribution, specific gravity, soil organic matter content, total and available nutrient element contents did not vary with the succession of rocky desertification.     

Transformation of organic carbon and its potential impact on lead weathering in firing range soils

Lead （Pb） is normally considered as a trace element in soils and sediments for geochemical study. However, the concentration of Pb in firing range soils is generally so high that it should be considered as a major element during the evaluation of the soil geochemical properties. Soil organic matter （SOM） has been reported as one of the major factors to expedite the corrosion of metallic lead （Pb） in acidic and organic-rich soils. The main impacts of SOM on the fate and transport of Pb in firing range soils lie in the following two aspects; （1） the complexation of organic matter with Pb, which has received lots of attention, and; （2） changes in soil redox potential due to the transformation of SOM and its subsequent impact on Pb speciation, which has rarely been investigated. Soils from 6 different firing ranges are selected for this study. These samples have been stored under a closed condition for more than 3 years. The soil moisture contents were well-retained, as all the samples were kept in closed plastic buckets. The analytical data showed that the summation of the soil total organic carbon content （TOC） and inorganic carbon contents （TIC） were consistent with soil total carbon contents （TC） measured in previous years, although the TOC and TIC contents have changed respectively after years of storage. In general, it is observed that the soil TOC decreased against an increase of TIC. The mass balance on such a transformation suggested a major conversion of organic carbon （Corg） to inorganic carbon （CO3^2-） in the stored soils.     

Effects of tree species and soil depths on ethylene and methane consumption in tropical and temperate forest soils

To date our knowledge is limited with regard to the responses of ethylene and methane consumption by forest soils to tree species and soil types, and to the effect of presence of ethylene on atmospheric methane consumption. The soils at depths from tropical and temperate forests in China were used to study the responses of ethylene and methane consumption to tree species and soil types. The ethylene and methane consumption by soils beneath each forest floor was measured under the same oxic conditions, along with main properties of forest soils. The accumulation of ethylene was studied in the soil slurry （soil/water, 1/2.5）. In temperate soils under spruce and birch forests, maximal consumption rates of ethylene and methane were observed in the 2.5-5.0 cm and 5.0-7.5 cm soil layers, respectively （P〈0.05）. However, a maximal consumption of both occurred in the 0-2.5 cm soil layer under temperate Korean pine forest （P〈0.05）. Contrary to temperate forest soils, there was a significant lower consumption of ethylene and methane in tropical forest soils at less than 20 cm depths under a seasonal rainforest and secondary rubber forest （P〈0.05）. Hence, the potential of ethylene and methane consumption in the 0-20 cm soil profile was variable with tree species and soil types. According to ethylene formation in the soil slurry, there was greater accumulation of ethylene in the 0-2.5 cm soil under temperate forests than under tropical forests, and its accumulation under spruce and birch forests was more than under Korean pine forest （P〈0.05）. The presence of extrinsic ethylene can significantly inhibit the consumption of atmospheric methane by forest soils.     

Variations in δ18O, δD,and the concentration of pollen and spores in an autochthonic heterogeneous massive ice on the Erkutayaha River in the southern part of the Yamal Peninsula

Doklady Earth Sciences -     

The record of temperature, wind velocity and air humidity in the δD and δO of water inclusions in synthetic and Messinian halites

Deuterium and oxygen isotope fractionations between liquid and vapor water were experimentally-determined during evaporation of a NaCl solution (35 g L⁻¹) as a function of water temperature and wind velocity. In the case of a null wind velocity, slopes of δD-δ¹⁸O trajectories of residual waters hyperbolically decrease with increasing water temperatures in the range 23-47 °C. For wind velocities ranging from 0.8 to 2.2 m s⁻¹, slopes of the δD-δ¹⁸O trajectories linearly increase with increasing wind velocity at a given water temperature. These experimental results can be modeled by using Rayleigh distillation equations taking into account wind-related kinetics effects. Deuterium and oxygen isotope compositions of water inclusions trapped by the precipitated halite crystals were determined by micro-equilibration techniques.These isotopic compositions accurately reflect those of the surrounding residual waters during halite growth. Isotopic compositions of water inclusions in twenty natural halites from the Messinian Realmonte mine in Sicily suggest precipitation temperatures of that match the homogenization temperatures obtained by microthermometry (median = 34 ± 5 °C). The similarity between the measured and experimental slopes of the δD-δ¹⁸O evaporation trajectories suggests that the effect of wind was negligible during the genesis of these halite deposits. Hydrogen and oxygen isotope compositions of water inclusions from Realmonte halite also define a linear trend whose extrapolation until intersection with the Mediterranean Meteoric Water Line allows the characterization of the water source with δD and δ¹⁸O values of −70 ± 10‰ and −11.5 ± 1.5‰, respectively. These results reveal that the huge amounts of salts deposited in Sicily result from the evaporation of seawater mixed with a dominant fraction (?50%) of meteoric waters most likely deriving from alpine fluvial discharge.     

Immobilization of Cu and As in two contaminated soils with zero-valent iron – Long-term performance and mechanisms

Immobilization of trace elements in contaminated soils by zero-valent iron (ZVI) is a promising remediation method, but questions about its long-term performance remain unanswered. To quantify immobilization and predict possible contaminant remobilization on long timescales detailed knowledge about immobilization mechanisms is needed. This study aimed at assessing the long-term effect of ZVI amendments on dissolved copper and arsenic in contaminated soils, at exploring the immobilization mechanism(s), and at setting up a geochemical model able to estimate dissolved copper and arsenic under different scenarios. Samples from untreated and ZVI-treated plots in two field experiments where ZVI had been added 6 and 15 years ago were investigated by a combination of batch experiments, geochemical modeling and extended X-ray absorption fine structure (EXAFS) spectroscopy. Dissolved copper and arsenic concentrations were described by a multisurface geochemical model with surface complexation reactions, verified by EXAFS. The ZVI remained “reactive” after 6–15 years, i.e. the dissolved concentrations of copper and arsenic were lower in the ZVI-treated than in the untreated soils. There was a shift in copper speciation from organic matter complexes in the untreated soil to surface complexes with iron (hydr)oxides in the ZVI-treated soil. The pH value was important for copper immobilization and ZVI did not have a stabilizing effect if pH was lower than about 6. Immobilization of arsenic was slightly pH-dependent and sensitive to the competition with phosphate. If phosphate was ignored in the modeling, the dissolution of arsenate was greatly underestimated.     

Ground ice recharge via brine transport in frozen soils of Victoria Valley, Antarctica: Insights from modeling δO and δD profiles

Soils in the McMurdo Dry Valleys, Antarctica contain ice and considerable amounts of salt. Ice often occurs at shallow depth throughout the Dry Valleys and other areas of hyperarid permafrost, notably on Mars. This common occurrence of shallow ice is enigmatic; however, since according to published sublimation models it should disappear relatively quickly (at rates of order 0.1 mm a⁻¹) due to vapor loss to the atmosphere. This loss may be offset by recharge from snowmelt infiltrating and freezing in the soil. Herein, we present a first quantitative estimate of this recharge based on measured vertical profiles of δD and δ¹⁸O that reveal considerable detail about the sources and sinks of ice. We model these profiles, taking into account the salt content and a soil temperature record along a 1.6 m depth profile of ∼10 ka old ice-cemented soils in Victoria Valley, Antarctica. The stable isotopes of ice are enriched in heavy isotopes at the top of the ice cement (20 cm depth); both δD and δ¹⁸O values plotted against depth exhibit a concave upward curve. At depth, the isotope composition is similar to that of Lake Victoria and modern meteoric water. The concave shape of the isotope profile is suggestive of downward advection-dispersion of snowmelt water enriched in heavy isotopes into the ice cement. Our advection-dispersion model, coupled with field data, enables us to quantify the advective flux and dispersion of melt water into the ice. The advective velocity and dispersion coefficient depend on the time since advection began and the ice-to-brine ratio; they are, respectively, of the order of 10⁻¹¹-10⁻¹⁰ m s⁻¹ and 10⁻¹²-10⁻¹¹ m² s⁻¹. These values suggest that over the ∼10 ka time period, a total of 190 mm water infiltrated into the ice-cemented ground. The isotope composition and deuterium excess values of the uppermost ice cement can be modeled from snowmelt water enriched in salts using open system-Rayleigh fractionation. To develop the isotopic signature of the upper ice cement requires evaporation of ∼95% of the snowmelt water. Based on 190 mm brine infiltrating into the soil requires an initial total of ∼4 m of snowmelt water. This corresponds to ∼0.4 mm a⁻¹ suggesting that, under the current climate condition, water from snowmelt is sufficient to compensate modeled sublimation rates, and therefore conserve ground ice in Victoria Valley.     

Synchronization of Variations in Geomagnetic Field Intensity with Eustatic Cycles and Bursts of Magmatism Intensification in the Cretaceous–Early Paleogene

Geotectonics - The relationship between cyclic processes in the core and lithosphere in the Middle Jurassic–Paleogene (167–22 Ma) was investigated. The dynamics of cyclic processes was...     

Variations in composition and δ18O values within the Kaffo albite—Riebeckite granite of Liruei Complex,Younger Granites of Nigeria

The peralkaline Kaffo albite—riebeckite granite is an albitised, low-temperature intrusion in Liruei Complex, one of the oldest of the ring-complexes in the Younger Granite province of Nigeria. Analyses of borehole samples from different parts of the intrusion show it to be compositionally heterogeneous, especially in respect of Si, Al, Na, K and F distribution and this, in part, can be correlated with the variable degree of albitisation. Isotopically the granite is a normal plutonic type with δ¹⁸ O values of $\text{+ 8.1 ± 0.2‰}$, and albitisation does not seem to have been accompanied by exchange of isotopes between albitising fluid and the granite. Co-existing riebeckitic-arfvedsonite and aegirine pairs from borehole samples show extreme enrichment in Na and Fe; the amphibole also shows considerable substitution of Fe by Ti, Zn and Mn, and of OH by F. Isotopically the amphibole and pyroxene are different from others, having low, variable δ¹⁸ O values (+5.3–+6.4 and $\text{+4.4–+5.1‰}$, respectively), and the fractionation value Δ Px — Am is always large, negative and constant (—$\text{1.2 ± 0.2‰}$). The low δ¹⁸ O values are considered to be due to special features of the crystal chemistry of the alkali amphiboles and pyroxenes, and the spread of each set of values may be due to sub-solidus isotope exchange between the minerals and albitising fluid.     

Mobility and accumulation of selenium and its relationship with other heavy metals in the system rocks/soils–crops in areas covered by black shale in Korea

The purpose of this study is to investigate the enrichment level and dispersion patterns of Se and associated elements in rocks, soils and crops which were collected in the Dukpyung and the Chubu areas covered with black shales of the Okchon Group in Korea. Rock and soil samples were analyzed for Se including multiple elements by ICP, ICP-MS and INAA, and crop samples by INAA. Soil pH and loss-on-ignition (LOI) were also measured.     

Controlling factors and environmental implications of mercury contamination in urban and agricultural soils under a long-term influence of a chlor-alkali plant in the North–West Portugal

This study aims at assessing the extent of total mercury (Hg) contamination in urban and agricultural soils under long-term influence of a chlor-alkali plant, located at about 1 km away from a town centre. Moreover, it aims at identifying the main factors controlling Hg contents’ distribution and associated potential hazards to environment and human health. The median value of total Hg for soil surface layer (0–10 cm) was 0.20 mg/kg (data ranging from 0.050 to 4.5 mg/kg) and for subsurface layer (10–20 cm) 0.18 mg/kg (data ranging from 0.046 to 3.0 mg/kg). The agricultural area showed higher Hg concentrations (ranging from 0.86 to 4.5 mg/kg) than urban area (ranging from 0.05 to 0.61 mg/kg), with some results exceeding target values set by the Dutch guidelines. Mercury concentrations observed in the studied area are more likely to be associated with the influence of the chlor-alkali plant and with the use of historically contaminated sludges and water from a nearby lagoon in agriculture, than to the impacts of urban development. The statistical correlations between Hg concentrations and soil properties suggest that anthropogenic metal sources should influence the spatial distribution more than the geological properties. Although the Hg emissions were drastically reduced 10 years ago, the area under influence of the chlor-alkali plant is still facing potential health and environmental threats arising from soil contamination.     

Temporal variations in the concentration and isotopic signature of ammonium- and nitrate–nitrogen in soils under a breeding colony of Black-tailed Gulls (Larus crassirostris) on Kabushima Island,northeastern Japan

Temporal variations in the concentration and N isotopic ratios of inorganic N (NH₄– and NO₃–N) as affected by the soil temperature regime together with the input of bird excreta were analyzed in a sedentary soil under a dense colony (1.6 nests/m²) of breeding Black-tailed Gulls (Laruscrassirostris: a ground-nesting seabird). Surface soil samples were taken monthly from mid-March to late July 2005 from Kabushima Island, Hachinohe, northeastern Japan. The spatial concentration of inorganic N in the soils varied considerably on all sampling dates. There may be a statistically significant trend, showing increased NH₄–N content from settlement up to early June when the input of fecal N attains its maximum, and then decreases towards the end of breeding activity (early August). Abundant NO₃–N was observed in all soils, particularly in the later stage of breeding (up to 3800 mg-N/kg dry soil), refuting earlier claims that nitrification is unimportant in the soils. δ¹⁵N values of NH₄ in the soils showed unusually high values up to +51‰, reflecting N isotope fractionation due to volatilization of NH₃ during the mineralization. Mean δ¹⁵N values of the monthly collected totals of NH₄ and NO₃ were not significantly different at the 5% level based on ANOVA and significant differences were observed only among the three means of NO₃–N collected in mid-March (settlement of colony: δ¹⁵N = −0.2 ± 3.5‰) and late July (later stages of breeding: δ¹⁵N = +22.1 ± 7.0‰, +23.3 ± 7.8‰) at the 1% and 5% levels by t-test, respectively. Such an observation of significantly increased δ¹⁵N values for NO₃–N in soils from the fledgling stage indicates the integration of denitrification coupled with nitrification under a limited supply of fecal N.     

The major ion, δCa, δCa, and δMg geochemistry of granite weathering at pH = 1 and T = 25 °C: power-law processes and the relative reactivity of minerals

We dissolved Boulder Creek Granodiorite in a plug flow reactor for 5794 h at pH = 1 and T = 25 °C. The primary purpose of the experiment was to identify controls on dissolved δ^44/40Ca, δ^44/42Ca, and δ^26/24Mg values during granite weathering. Herein, we also examine the origin of Ca and Mg isotopic variability among minerals composing the Boulder Creek Granodiorite, and we constrain fundamental characteristics of granite weathering important for quantifying the elemental and isotopic geochemistry of the reactor output. Nine Ca-bearing minerals display an 8.80‰ range of δ^44/40Ca values and a 0.51‰ range of δ^44/42Ca values. Three Mg-bearing minerals display a 1.53‰ range of δ^26/24Mg values. These ranges expressed at the mineralogical scale are higher than the ranges thus far reported for bulk igneous rocks. Most of the δ^44/40Ca variability reflects ⁴⁰Ca enrichment in K-feldspar, and to a lesser extent, biotite, due to the radioactive decay of ⁴⁰K over the 1.7 Ga age of the rock, whereas the entire range of δ^44/42Ca values reflects mass-dependent isotope fractionation during igneous differentiation and crystallization. The range of δ^26/24Mg values may represent either fractionation during the chloritization of biotite or interaction of the Boulder Creek Granodiorite with Mg-rich metamorphic fluids having low δ^26/24Mg values.The elemental and isotopic composition of the reactor output varied substantially during the experiment. We synthesize the mineralogical and fluid data using coupled mass-conservation equations solved at non-steady-state. Model calculations reveal an intricate balance between increasing specific surface area and decreasing mineral concentrations. While surface area normalized dissolution rate constants were time-invariant, specific surface area increased as a power-law function of time through positive feedbacks between mechanical disaggregation, chemical dissolution, and mineral depletion. Variations in dissolved δ^44/40Ca, δ^44/42Ca, and δ^26/24Mg values reflect conservative mixing rather than fractionation. Apatite and calcite initially control δ^44/40Ca and δ^44/42Ca values, followed by biotite, titanite, epidote, hornblende, and plagioclase. The release of radiogenic ⁴⁰Ca clearly defines the period where biotite dissolution dominates. The brucite layer of chlorite initially controls δ^26/24Mg values, followed by biotite, the TOT layer of chlorite, and hornblende. Through direct isotopic tracking, these results demonstrate that trace minerals, such as apatite and calcite in the case of Ca and brucite in the case of Mg, dominate elemental release during the incipient stages of granite weathering. The results further show that biotite dissolution dominates the middle stages of granite weathering and that plagioclase dissolution only becomes important during relatively late stages. The Ca and Mg isotope variations associated with these stages are distinct and potentially resolvable in soil mineral weathering studies.     

Speleothem calcite farmed in situ: Modern calibration of δO and δC paleoclimate proxies in a continuously-monitored natural cave system

Understanding the relationships between speleothem stable isotopes (δ¹³C δ¹⁸O) and in situ cave forcing mechanisms is important to interpreting ancient stalagmite paleoclimate records. Cave studies have demonstrated that the δ¹⁸O of inorganically precipitated (low temperature) speleothem calcite is systematically heavier than the δ¹⁸O of laboratory-grown calcite for a given temperature. To understand this apparent offset, rainwater, cave drip water, groundwater, and modern naturally precipitated calcite (farmed in situ) were grown at multiple locations inside Hollow Ridge Cave in Marianna, Florida. High resolution micrometeorological, air chemistry time series and ventilation regimes were also monitored continuously at two locations inside the cave, supplemented with periodic bi-monthly air gas grab sample transects throughout the cave.Cave air chemistry and isotope monitoring reveal density-driven airflow pathways through Hollow Ridge Cave at velocities of up to 1.2 m s⁻¹ in winter and 0.4 m s⁻¹ in summer. Hollow Ridge Cave displays a strong ventilation gradient in the front of the cave near the entrances, resulting in cave air that is a mixture of soil gas and atmospheric CO₂. A clear relationship is found between calcite δ¹³C and cave air ventilation rates estimated by proxies pCO₂ and ²²²Rn. Calcite δ¹³C decreased linearly with distance from the front entrance to the interior of the cave during all seasons, with a maximum entrance-to-interior gradient of Δδ¹³C_CaCO3 = −7‰. A whole-cave “Hendy test” at multiple contemporaneous farming sites reveals that ventilation induces a +1.9 ± 0.96‰ δ¹³C offset between calcite precipitated in a ventilation flow path and calcite precipitated on the edge or out of flow paths. This interpretation of the “Hendy test” has implications for interpreting δ¹³C records in ancient speleothems. Calcite δ¹³C_CaCO3 may be a proxy not only for atmospheric CO₂ or overlying vegetation shifts but also for changes in cave ventilation due to dissolution fissures and ceiling collapse creating and plugging ventilation windows.Farmed calcite δ¹⁸O was found to exhibit a +0.82 ± 0.24‰ offset from values predicted by both theoretical calculations and laboratory-grown inorganic calcite. Unlike δ¹³C_CaCO3, oxygen isotopes showed no ventilation effects, i.e. Δδ¹⁸O_CaCO3 appears to be a function of growth temperature only although we cannot rule out a small effect of (unmeasured) gradients in relative humidity (evaporation) accompanying ventilation. Our results support the findings of other cave investigators that water-calcite fractionation factors observed in speleothem calcite are higher that those measured in laboratory experiments. Cave and laboratory calcite precipitates may differ mainly in the complex effects of kinetic isotope fractionation. Combining our data with other recent speleothem studies, we find a new empirical relationship for cave-specific water-calcite oxygen isotope fractionation across a range of temperatures and cave environments:

1000lnα=16.1(10³T^-1)-24.6     

The preference of nitrate uptake in Chinese prickly ash estimated by δ<Superscript>15</Superscript>N values and cation concentrations

The nitrogen isotopic compositions of plant tissue could reflect its uptake of and preference for ammonium or nitrate. However, various factors may influence the field-collected δ¹⁵N values under field condition, which causes the interpretation problematic. The spatial variation of nitrogen (N) concentrations and the isotopic compositions were investigated in the soils and tissues of Chinese prickly ash from the southwest China to the east China. The objectives were to investigate the variation in soil and tissue δ¹⁵N values and N forms taken up by the plant. The leaf and root δ¹⁵N values varied significantly in response to the pattern of soil δ¹⁵N values. The difference in δ¹⁵N values between the leaves and roots was 2.57‰ and may be caused by an increase in the transport of unassimilated \( {\text{NO}}_{3}^{ - } \) and \( {\text{NH}}_{4}^{ + } \) to the leaves. Leaf nitrogen was significantly and positively correlated with leaf potassium and negatively related to leaf calcium. Because potassium is the favoured counter-cation for nitrate transport in the xylem, the enrichment of ¹⁵N in leaf relative to root induced by preferenced uptake of nitrate should be accompanied by significant and positive relationship of leaf nitrogen with leaf potassium concentrations. These results suggest that Chinese prickly ash prefers \( {\text{NO}}_{3}^{ - } \) over \( {\text{NH}}_{4}^{ + } \).     

234U/238U and δ87Sr in peat as tracers of paleosalinity in the Sacramento-San Joaquin Delta of California,USA

The purpose of this study was to determine the history of paleosalinity over the past 6000+ years in the Sacramento-San Joaquin Delta (the Delta), which is the innermost part of the San Francisco Estuary. We used a combination of Sr and U concentrations, δ⁸⁷Sr values, and ²³⁴U/²³⁸U activity ratios (AR) in peat as proxies for tracking paleosalinity. Peat cores were collected in marshes on Browns Island, Franks Wetland, and Bacon Channel Island in the Delta. Cores were dated using ¹³⁷Cs, the onset of Pb and Hg contamination from hydraulic gold mining, and ¹⁴C. A proof of concept study showed that the dominant emergent macrophyte and major component of peat in the Delta, Schoenoplectus spp., incorporates Sr and U and that the isotopic composition of these elements tracks the ambient water salinity across the Estuary. Concentrations and isotopic compositions of Sr and U in the three main water sources contributing to the Delta (seawater, Sacramento River water, and San Joaquin River water) were used to construct a three-end-member mixing model. Delta paleosalinity was determined by examining variations in the distribution of peat samples through time within the area delineated by the mixing model.The Delta has long been considered a tidal freshwater marsh region, but only peat samples from Franks Wetland and Bacon Channel Island have shown a consistently fresh signal (<0.5 ppt) through time. Therefore, the eastern Delta, which occurs upstream from Bacon Channel Island along the San Joaquin River and its tributaries, has also been fresh for this time period. Over the past 6000+ years, the salinity regime at the western boundary of the Delta (Browns Island) has alternated between fresh and oligohaline (0.5–5 ppt).     

A compound-specific n-alkane δC and δD approach for assessing source and delivery processes of terrestrial organic matter within a forested watershed in northern Japan

We measured molecular distributions and compound-specific hydrogen (δD) and stable carbon isotopic ratios (δ¹³C) of mid- and long-chain n-alkanes in forest soils, wetland peats and lake sediments within the Dorokawa watershed, Hokkaido, Japan, to better understand sources and processes associate with delivery of terrestrial organic matter into the lake sediments. δ¹³C values of odd carbon numbered C₂₃-C₃₃n-alkanes ranged from −37.2‰ to −31.5‰, while δD values of these alkanes showed a large degree of variability that ranged from −244‰ to −180‰. Molecular distributions in combination with stable carbon isotopic compositions indicate a large contribution of C3 trees as the main source of n-alkanes in forested soils whereas n-alkanes in wetland soil are exclusively derived from marsh grass and/or moss. We found that the n-alkane δD values are much higher in forest soils than wetland peat. The higher δD values in forest samples could be explained by the enrichment of deuterium in leaf and soil waters due to increased evapotranspiration in the forest or differences in physiology of source plants between wetland and forest. A δ¹³C vs. δD diagram of n-alkanes among forest, wetland and lake samples showed that C₂₅-C₃₁n-alkanes deposited in lake sediments are mainly derived from tree leaves due to the preferential transport of the forest soil organic matter over the wetland or an increased contribution of atmospheric input of tree leaf wax in the offshore sites. This study demonstrates that compound-specific δD analysis provides a useful approach for better understanding source and transport of terrestrial biomarkers in a C3 plant-dominated catchment.