Across tropical South America, forest soils are typically of a higher cation status than their savanna equivalents with soil exchangeable potassium a key soil nutrient differentiating these two vegetation types. Differences in soil water storage capacity are also important – interacting with both potassium availability and precipitation regimes in a relatively complex manner.

This research reports a test of the applicability of three organic-derived temperature proxies (UK'37, TEX86 and LDI) at high latitudes around Iceland. A range of samples including suspended particular material (SPM), trapped descending particles and surface sediments were collected to test the different proxies in the water column and the sediment.The combination of three independent SST organic proxies provided important information about seasonality and differences in habitat depth.

People worldwide use fire to manage agriculture, but often also suppress fire in the landscape surrounding their fields. Here, we estimate the net result of these effects of cropland and pasture on fire at a regional, monthly level. Pasture is shown, for the first time, to contribute strongly to global patterns of burning. Our results could be used to improve representations of burning in global vegetation and climate models, improving our understanding of how people affect the Earth system.

Bosten Lake is the largest inland freshwater lake in China, which has been impacted by land use changes, with implications for carbon burial. Our study showed a large spatial variability in total organic carbon (TOC) (1.8–4.4%); 54–90% of TOC was from autochthonous sources. Higher TOC content was found in the east and central-north sections and near the mouth of the Kaidu River, which was attributable to allochthonous, autochthonous plus allochthonous, and autochthonous sources, respectively.

We investigated the role of water availability in shaping forest carbon cycling and conifer morphological traits in the Cascade Mountains, Oregon, a region that is expected to become warmer and drier in the coming century. Forest leaf area, productivity, and biomass were strongly related to mean annual water availability. Across the hydroclimatic gradient, trees exhibited interspecific variation in traits that balanced maintaining hydraulic function against the need to compete for light.

We integrated satellite synthetic aperture radar (SAR), lidar, and forest plot data to calculate the amount and loss of above-ground biomass in remaining tall natural forests in a section of Sumatra, with quantified uncertainties. We estimate very high deforestation rates of 3.8% yr-1 and the loss of 11.3% remaining forest biomass in only 3 years. L-band SAR is valuable for penetrating cloud for deforestation analyses and for reliably estimating the carbon emissions from land use change.

The time series analysis of the main meteorological parameters and components of CO2 and H2O fluxes showed a high evapotranspiration (ET) and gross primary production (GPP) sensitivity of the tropical rainforest to meteorological variations caused by El Niño-Southern Oscillation (ENSO) events. Incoming solar radiation is the main governing factor that is responsible for ET and GPP variability. Changes in precipitation due to moderate ENSO events did not have any notable effect on ET and GPP.

This study investigates how sunlight, dissolved organic matter (DOM) concentration and composition, and hydrology interact to control DOM degradation in headwater streams. In Imnavait Creek, a shallow, low-relief stream in the Arctic, DOM degradation by sunlight was limited by light under all conditions. Study results were used to synthesize controls on DOM degradation by sunlight for a river reach, expressed as a function of light attenuation and water residence times.

We combined field, laboratory (sediment-flow-through system) and numerical modeling work to investigate cold seep sediments at Quespos Slide, offshore of Costa Rica. The results demonstrated the efficiency of the benthic methane filter and provided an estimate for its response time (ca. 170 days) to changes in fluid fluxes.

Canopy height and gaps of tropical peat swamp forests, measured by airborne laser scanning, were influenced by an interplay of environmental factors and selective logging. Structural recovery after logging depended strongly on peat depth and the landscape-scale relationship between forest height and canopy gap structure was lost in selectively logged forests. Results suggest slowest recovery on deep waterlogged and infertile peat, which is of relevance to management and conservation activities.

Extracting benthic oxygen fluxes from eddy covariance data measured in the presence of wave motions requires careful consideration of the temporal alignment of the vertical velocity and the oxygen concentration. We show that substantial errors in flux estimates can arise if these two variables are not aligned correctly in time. Due to the limited time response of all oxygen sensors used today, such a misalignment cannot be entirely avoided. We finally propose a new correction for this problem.

Our study investigated the effect of coniferous and deciduous vegetation on Hg cycling. We quantified Hg in aboveground vegetation and soil horizons at eight paired forest sites. Organic horizons at coniferous stands had greater Hg concentrations and pools than deciduous stands. Mineral soil Hg pools did not vary with vegetation type but varied with soil chemical properties. Estimated Hg litterfall flux was greater at deciduous stands. A shift in vegetation type may impact Hg accumulation.

Soil microbial biomass carbon (Cmic) and nitrogen (Nmic) and microbial quotient varied substantially across China’s forest ecosystems (CV 61–96%). Soil resources and climate together explained 24–41% of the variations. Cmic:Nmic ratio declined slightly with soil C:N ratio and changed with latitude and climate, suggesting a plastic homeostasis of microbial C-N stoichiometry. Divergent responses of microbial quotient of C and N to environment imply different mechanisms regulating Cmic and Nmic.

Evaluation of a unique 20-year-long time series of inorganic carbon and nutrient observations from the West Antarctic Peninsula region shows that summertime biological productivity and meltwater input drive a large range of surface aragonite saturation states from values < 1 (undersaturated) up to 3.9. Even though we did not detect any statistically significant long-term trends, ongoing ocean acidification and freshwater input may soon induce more unfavorable conditions than seen today.

We determined the isotopic composition of chlorophyll a in periphytic algae attached to a streambed substrate (periphyton). Although the bulk isotopic composition of periphyton is recognised as a surrogate for the photosynthetic algal community, our results indicate that the bulk periphyton matrix at the study site consists of 89 to 95% algal carbon and 5 to 11% terrestrial organic carbon. We show that the chlorophyll a isotopic composition is a useful tracer for the aquatic food web studies.

This study evaluated the sensitivity of silicate mineral dissolution rates to intrinsic and extrinsic factors using a soil evolution model, SoilGen2.25. Modelling results showed a dominant role of pH and a direct effect of soil texture on dissolution rates. Clay migration and plant nutrient recycling influenced the pH and thus the dissolution rates. These results demonstrate the need to couple different soil processes in order to explain differences between lab and field dissolution rates.

We observed that phytoplankton biomass and growth rate (μ), microzooplankton grazing rate (m), and coupling (correlation) between the μ and m significantly varied between the summer and winter, and microzooplankton selectively grazed more on the larger-sized phytoplankton, and a low grazing impact on phytoplankton (m/μ < 50%) in the SSCS. The salient seasonal variations in μ and m, and their coupling were closely related to environmental variables under the influence of the East Asian monsoon.

Sunlight-initiated photochemistry plays an important role in carbon and trace gases cycling in natural waters. We for the first time confirm that photochemical degradation of dissolved organic carbon (DOC) can produce methane, which is the second most important greenhouse gas in the atmosphere. Dissolved oxygen greatly affects the rates of DOC photodegradation and methane photoproduction. The implications of methane photoproduction for methane cycling in modern and ancient oceans are discussed.