Recent  

Tree canopies are strong moderators of understory climatic conditions. In tropical areas, trees cool down the microclimates. We show using remote sensing and field measurements how even intermediate canopy cover and agroforestry trees contributed to buffering the hottest temperatures in Kenya. The cooling effect was the greatest during hot days and in lowland areas, where the ambient temperatures were high. Adopting agroforestry practices in the area could assist in mitigating climate change.

Actual maps of grassland traits could improve local farm management and support environmental assessments. We developed, assessed, and applied models to estimate dry biomass and plant N concentration in pre-Alpine grasslands with drone-based multispectral data and canopy height information. Our results indicate that machine learning algorithms are able to estimate both parameters, but reach a better performance for biomass.

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

Arctic warming and permafrost degradation largely affect tundra vegetation. Wetter lowlands show increase in sedges, whereas drier uplands favor shrub expansion. Here, we demonstrate that the difference in the foliar elemental composition of typical tundra vegetation species controls the local foliar elemental stock and the potential mineral element cycling through litter production upon shift in tundra vegetation.

Information on the marine carbon dioxide system along the Inside Passage of the Pacific Northwest coast of North America has been limited. To address this gap, we instrumented an Alaskan ferry in order to characterize the marine carbon dioxide system. Data over a 2-year period were used to assess drivers of the observed variability, identify the timing of severe conditions, and assess the extent of contemporary ocean acidification as well as future levels consistent with a 1.5 °C warmer climate.

Respiration is made up of plant and peat sources. How to separate these sources is not well known as peat respiration is influenced by vegetation dynamics, especially in grass-dominated peatlands. Results of plot level measurements from shrubs and sparse grasses in a woody bog show that a plant’s respiration response to changes in climate is related to different mechanisms of obtaining water resources. Hence, respiration is influenced differently than in a grass-dominated peatland.

Planetary warming is increasing seasonal thaw of permafrost, making this extensive old carbon stock vulnerable. In Northern Alaska, we found more and older dissolved organic carbon in small drainages later in summer as more permafrost was exposed by deepening thaw. Younger and older carbon did not differ in chemical indicators related to biological lability suggesting this carbon can cycle through aquatic systems and contribute to greenhouse gas emissions warming increases permafrost thaw.

Deep-living organisms are a major yet poorly known component of ocean biomass. Here we reconstruct the evolution of deep-living zooplankton and phytoplankton. Deep dwelling zooplankton and phytoplankton did not occur when the ocean was several degrees warmer than today, 15 million years ago. Deep-dwelling species first evolve around 7.5 million years ago, following global climate cooling. Their evolution was driven by colder ocean temperatures allowing more food, oxygen and light at depth.

We developed and used a terrestrial biosphere model to compare and evaluate widely used empirical dry deposition schemes with different stomatal approaches, and found that using photosynthesis-based stomatal approaches can reduce biases in modelled dry deposition velocities in current chemical transport models. Our study shows systematic errors in current dry deposition schemes, and the importance of representing plant ecophysiological processes in models under a changing climate.

Empirical information on the nutrient cycles in the second largest European Lake Onego is almost lacking. We covered the deficit by realistic simulation of the lake’s ecosystem dynamics during 1985–2015 with the 3D ecohydrodynamic model. Important results include: a) 3D dynamics of major nutrient variables and fluxes; b) quantification of the spring phytoplankton bloom, previously overlooked; c) coherent nutrient budgets. The model is a useful tool for forecasting with different scenarios.

This study presents a new individual-based vegetation model to investigate salinity control on mangrove productivity. The model incorporates plant hydraulics and tree competition and predicted unique and complex patterns of mangrove forest structures that varies across soil salinity gradient. The presented model does not hold an empirical expression of salinity influence on productivity, and thus may provide a better understanding of mangrove forest dynamics in future climate change.

We analysed the evolution of model parameter uncertainty and prediction error as we updated a maize phenology model based on yearly observations, by applying Bayesian calibration sequentially. Even though parameter uncertainty reduced, prediction quality deteriorated when data used for calibration and prediction were from different maize ripening groups or temperature conditions. Bayesian calibration methods should account for model limitations and inherent structure in the data.

We measured concentrations of five different organic gases in seawater in the high Arctic during summer. We found higher concentrations near the surface of the water column (top 5–10 m) and in areas of partial ice cover. This suggests that the sea ice influences the concentrations of these gases. These gases indirectly exert a slight cooling effect on the climate and it is therefore important to measure the levels accurately for future climate predictions.

To understand the CH₄ flux potential of natural ecosystems and agricultural lands in the United States (US) of America, a multi-scale CH₄ observation network focused on CH₄ flux rates, processes, and scaling methods is required. This can be achieved with a network of ground-based observations that are distributed based on climatic regions and landcover.

Anaerobic ammonium oxidation (anammox) is an important nitrogen-removal process in the ocean. We assess the distribution of bacteriohopanetetrol-x (BHT-x), used to trace past anammox, along a redox gradient in the water column of the Benguela upwelling system. BHT-x/BHT ratios of > 0.18 correspond to the presence of living anammox bacteria and oxygen levels < 50 μmol L⁻¹. This allows for a more robust application of BHT-x to trace past marine anammox and deoxygenation in dynamic marine systems.

Gaseous mercury is present in the atmosphere all over the globe. During the growing season, plants take up mercury from the air in a similar way as CO₂. We investigated, which factors impact this vegetational mercury uptake by analyzing a large dataset of mercury uptake rates by forest trees in Europe. As a result, we conclude, that mercury uptake is foremost controlled by tree-intrinsic traits like physiological activity, but also by climatic factors like dry conditions in the air and in soils.

Zooplankton play a key role in marine ecosystems, representing the base of marine food webs and a link between primary producers and higher-order consumers, such as fishes. This aspect is crucial in the Adriatic basin, one of the most productive and overexpoited area of the Mediterranean Sea. Thus, a better understanding of communities' and food web structure, and their response to water masses' changes is essential under a global warming scenario, being zooplankton sensitive to climate change.

Although vegetation responds to climate at a wide range of timescales, models of the land carbon sink often ignore responses that don’t occur instantly. In this study, we explored 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.

While carbon (C) and greenhouse gas (GHG) research has adopted appropriate technology and approach (AT&A) such as low-cost instrument, open source software and participatory research and their results were well accepted by scientific communities. In terms of cost, feasibility and performance, integration of low-cost and low-technology, participatory and networking based research approaches can be AT&A for enhancing C and GHG research in developing countries.

POC in the XLD and XJB reservoirs mainly originates from terrestrial POC (56 %). CH₄ oxidation potentially influences the variations in CH₄ concentrations and δ¹³C-CH₄ in cascade reservoirs. Water level variations and flow regulation caused by reservoir operation are primary factors for the input of terrestrial POC. The cumulative effect of POC at a bimonthly scale was not significant in the XLD and XJB reservoirs. Terrestrial POC displays more persistent impacts on CH₄ accumulation.

Since current estimates show that only about 1 % of the all plastic that enters the ocean is floating at the surface, we look at subsurface processes that can cause vertical movement of (micro)plastic. We investigate how modeled algal attachment and the ocean’s vertical movement can cause particles to sink and oscillate in the open ocean. Particles can sink to depths of > 5000 m in regions with high wind intensity and mainly remain close to the surface with low winds and biological activity.

This study analyses if the amount of nutrients in the fish biomass is significant compared to the nutrients available in the water column and also if the cycling rates of nutrients by the fish biomass is significant compared to how much nutrients primary producers need to grow. The use of a global model of commercially-targeted fish biomass allow us to assess these contributions of fish at the global scale, in a pristine ocean as well at the time of the global peak catch.

Measurements on sea-dwelling shelled organisms called foraminifera retrieved from deep-sea sediment cores have been used to reconstruct sea surface temperature (SST) variation. To evaluate the method, we use a computer model to simulate millions of single foraminifera and how they become mixed in the sediment after being deposited on the sea floor. We compare the SST inferred from the single foraminifera in the sediment core to the true SST in the water, thus quantifying method uncertanties.

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.