Permafrost thaw-driven landslides in the western Arctic are increasing organic carbon delivered to headwaters of drainage networks in the western Canadian Arctic by orders of magnitude. Through a series of laboratory experiments, we show that less than 10 % of this organic carbon is likely to be mineralized to greenhouse gases during transport in these networks. Rather most of the organic carbon is likely destined for burial and sequestration for centuries to millennia.

Quantifying biomass loss rates due to stem mortality is important for estimating the role of tropical forests in the global carbon cycle. We analyse the consequences of long-term elevated stem mortality for tropical forest dynamics and biomass loss. Based on simulations, we developed a statistical model to estimate biomass loss rates of forests in different successional states from forest attributes. Assuming a doubling of tree mortality, biomass loss increased from 3.2 % yr^-1 to 4.5 % yr^-1.

Although vegetation responds to climate at a wide range of timescales, models of the land carbon sink often ignore responses that do not occur instantly. In this study, we explore the timescales at which Australian ecosystems respond to climate. We identified that carbon and water fluxes can be modelled more accurately if we include environmental drivers from up to a year in the past. The importance of antecedent conditions is related to ecosystem aridity but is also influenced by other factors.

Understanding how vegetation might respond to climate change is especially important in arctic–alpine ecosystems, where major shifts in shrub growth have been observed. We studied how such changes come to pass and how future changes might look by measuring hourly variations in the stem diameter of dwarf shrubs from one common species. From these data, we are able to discern information about growth mechanisms and can thus show the complexity of shrub growth and micro-environment relations.

Peatlands are large sources of methane (CH₄), and peat structure controls CH₄ production and emissions. We used X-ray microtomography imaging, complex network theory methods, and pore network modeling to describe the properties of peat macropore networks and the role of macropores in CH₄-related processes. We show that conditions for gas transport and CH₄ production vary with depth and are affected by hysteresis, which may explain the hotspots and episodic spikes in peatland CH₄ emissions.

Droughts and heatwaves are expected to occur more often in the future, but their effects on land vegetation and the carbon cycle are poorly understood. We use six climate scenarios with differing extreme occurrences and a vegetation model to analyse these effects. Tree coverage and associated plant productivity increase under a climate with no extremes. Frequent co-occurring droughts and heatwaves decrease plant productivity more than the combined effects of single droughts or heatwaves.

Little is known about the impact of rubber plantations on diversity of the Great Mekong Subregion. In this study, we uncovered latitudinal gradients of plant diversity of rubber plantations. Exotic species with high dominance result in loss of plant diversity of rubber plantations. Not all exotic species would reduce plant diversity of rubber plantations. Much more effort should be made to balance agricultural production with conservation goals in this region.

Estuaries can significantly alter nutrient loads before reaching coastal waters. Our study of the heavily managed Ems estuary (Northern Germany) reveals three zones of nitrogen turnover along the estuary with water-column denitrification in the most upstream hyper-turbid part, nitrate production in the middle reaches and mixing/nitrate uptake in the North Sea. Suspended particulate matter was the overarching control on nitrogen cycling in the hyper-turbid estuary.

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, with 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.

We studied the isotopic composition of oxygen dissolved in seawater in the South China Sea. This tells us about the origin of oxygen in the water column, distinguishing between biological oxygen produced by phytoplankton communities and atmospheric oxygen entering seawater through gas exchange. We found that the East Asian Monsoon plays an important role in determining the amount of oxygen produced vs. consumed by the phytoplankton, as well as in inducing vertical water mass mixing.

This study tested combinations of two sources of AGB data and two sources of LCC data and used the same burned area satellite data to estimate BB CO emissions. Our analysis showed large discrepancies in annual mean CO emissions and explicit differences in the simulated CO concentrations among the BB emissions estimates. This study has confirmed that BB emissions estimates are sensitive to the land surface information on which they are based.

Buried animal and plant remains (carbon) from the last ice age were freeze-locked in permafrost. At an extremely fast eroding permafrost cliff in the Lena Delta (Siberia), we found this formerly frozen carbon well preserved. Our results show that ongoing degradation releases substantial amounts of this carbon, making it available for future carbon emissions. This mobilisation at the studied cliff and also similarly eroding sites bear the potential to affect rivers and oceans negatively.