Recent  

Soil organic carbon (SOC) is crucial for climate regulation, soil quality and food security. Predicting its evolution over the next decades is key for appropriate land management policies. However, SOC projections lack accuracy. Here, we show for the first time that PARTYsoc, an approach combining thermal analysis and machine-learning optimizes the accuracy of SOC model simulations at independent sites. This method can be applied at large scales, improving SOC projections on a continental scale.

A series of submarine sinkholes were recently discovered on Luymes Bank, part of Saba Bank, a carbonate platform in the Caribbean Netherlands. Here, we investigate the waters inside these sinkholes for the first time. One of the sinkholes contained a body of dense, low-oxygen and low-pH water, which we call the 'acid lake'. We use measurements of seawater chemistry to work out what processes were responsible for forming the acid lake, and discuss the consequences for the carbonate platform.

For the first time, microwave vegetation optical depth data are assimilated in a land surface model in order to analyze leaf area index and root-zone soil moisture. The advantage of microwave products is the higher observation frequency. A large variety of independent datasets are used to verify the added value of the assimilation. It is shown that the assimilation is able to improve the representation of soil moisture, vegetation conditions, and terrestrial water and carbon fluxes.

The carbon sequestration potential of two street tree species and their soil beneath was quantified with an urban land surface model SUEWS and soil carbon model Yasso. The street tree plantings turned into a modest sink of carbon from the atmosphere after 14 years. Overall, the results indicate the importance of soil in urban carbon sequestration estimations, as soil respiration exceeded the carbon uptake in the early phase, due to the high initial carbon loss from the soil.

This work presents original results regarding the effects of climate change on the European croplands and grasslands systems. We provided a detailed analysis about productivity, greenhouse gas emissions, carbon balance and water demand. Our integrative results can be useful in support decision making to identify future actions targeted to sustain productivity and reduce environmental impacts.

Acetate is an important intermediate during the anaerobic degradation of organic matter. It is consumed by methanogenic and sulfidogenic microorganisms accompanied by stable carbon isotope fractionation. We determined isotope fractionation under different conditions in two paddy soils and two lake sediments, and also determined the composition of the microbial communities. Despite a relatively wide range of experimental conditions, the range of fractionation factors was quite moderate.

With global warming, permafrost thaw and associated carbon release are of increasing importance. We examined how large herbivorous animals affect Arctic landscapes and how they might contribute to reduction of these emissions. We show that over a short timespan of roughly 25 years, these animals have already changed the vegetation and landscape. On pastures in a permafrost area in Siberia we found smaller thaw depth and higher carbon content than in surrounding non-pasture areas.

Two domestic on-site wastewater treatment systems have been monitored for greenhouse gas (carbon dioxide, methane and nitrous oxide) emissions coming from the process units, the soil and vent pipes. This has enabled the net greenhouse gas per person to be quantified for the first time, as well as the impact of pre-treatment on the effluent before being discharged to soil. These decentralised wastewater treatment systems serve approx. 20 % of the population in both Europe and the United States.

Hydrodynamics drive the distribution of plant communities in wetlands to form vegetation zones where the emission of N₂O varies with plant species. The N₂O emission decreased with the increase in carbon to nitrogen ratio of sediments, approximating a threshold. The distribution of plants under hydrodynamics modified the sedimental chemistry, resulting in the variations of bacteria. Hydraulic regulation rather than direct planting would be an effective strategy to reduce N₂O in wetlands.

A predictor selection algorithm was constructed to decreasing the predicating error in the surface ocean partial pressure of CO₂ (pCO₂) mapping by finding better combinations of pCO₂ predicators in different regions. Comparing with previous researches that using same combination of predictors in all regions, using different predictors selected by the algorithm in different regions can effectively decrease the pCO₂ predicating errors.

Although water availability has been linked to the response of ecosystem carbon (C) sink/source to climate warming, the mechanisms by which C uptake responds to soil moisture remain unclear. We explored how soil water and other environmental drivers modulate net C uptake in an alpine swamp meadow. Results reveal that nearly saturated soil conditions during warm seasons can help to maintain lower ecosystem respiration and therefore enhance the C sequestration capacity in this alpine swamp meadow.

Causal structure discovery algorithms have been making headway into Earth system sciences and they can be used to e.g. increase our understanding on biosphere-atmosphere interactions. In this paper we present a procedure on how to utilise prior knowledge of the domain experts together with these algorithms in order to find more robust causal structure models. We also demonstrate how to avoid such pitfalls as overfitting and concept drift during this process.

In this study, we investigate the chemical diversity and abundance of microbial lipids as markers of organic matter sources in the deepest points of the Atacama Trench sediments, and compare them to similar lipids stocks in shallower surface sediments and in the overlying water column. We evaluate possible organic matter provenance and some potential chemical adaptations of the in situ microbial community to the extreme conditions of high hydrostatic pressure in hadal realm.

We measured CH₄ fluxes and production and oxidation potentials from irrigated and non-irrigated podzolic soil in a boreal forest. CH₄ sink was smaller at the irrigated site, but did not cause CH₄ emission without one exception. We also showed that under laboratory conditions, not only wet conditions but also fresh carbon are needed to make podzolic soil into a CH₄ source. Our study provides important data for improving the process models describing the upland soil CH₄ dynamics.

The study assesses the impacts of cover crop practices on soil carbon, nitrogen leaching, and crop yields in comparison to a control management scenario with bare soil fallowing by applying the global vegetation model LPJml (V.5.0-tillage-cc). The potential and determinants of environmental and agronomic benefits of the practice vary with respect to management duration, type of tillage, mineral fertilizer application rate, and environmental conditions of the cropland.

Temporal change of plankton growth & grazing are less known in the coastal ocean, not to mention the relevant controlling mechanisms. Here, we performed monthly size-specific dilution experiments outside a eutrophic estuary over a year cycle. Phytoplankton growth was correlated to nutrients with grazing mortality to total chlorophyll-a. A selective grazing on small cells may be important for maintaining high abundance of large chain-forming diatoms in this eutrophic system.

Progressive ocean acidification and eutrophication pose a threat to skeletal calcification of reef corals. Recent upwelling areas serve as natural laboratories to study their calcification response to low seawater pH and eutrophic conditions. We compare patterns of reef coral calcification from the Arabian Sea upwelling zone with those from typical reef environments and identify nutrient conditions that contribute to the maintenance of high calcification rates in times of global change.

The shell of the California mussel contains alternating dark and light calcium carbonate increments that record whether the shell was growing normally under optimal conditions (light) or slowly under sub-optimal conditions (dark). However, the timing and specific environmental controls of growth band formation have not been tested. We investigated these controls and found links between stable seawater temperatures and light bands and highly variable or extreme temperatures and dark bands.

Amino acids were analyzed in a large number of samples of particulate and dissolved organic matter from coastal regions and the open ocean. A statistical analysis produced two new biogeochemical indicators. An indicator of sinking particle and sediment degradation (SDI) traces the degradation of organic matter from the surface waters into the sediments. A second indicator of shows the residence time of suspended matter in the ocean (RTI).

N₂O emissions from permafrost soils represent up to 11.6 % of total N₂O emissions from natural soils and their contribution to the global N₂O budget will likely increase due to climate change. A better understanding of N₂O production from permafrost soils is needed to evaluate the role of Arctic ecosystems in the global N₂O budget. By studying microbial N₂O production processes in N₂O hotspots in permafrost peatlands we identified denitrification as the dominant source of N₂O in these surfaces.