Recent  

Understanding what determines establishment of dune-building vegetation could help to better predict coastal dune initiation and development. We monitored the establishment of dune building grasses and dune initiation in a large field experiment. Our results show that dune initiation takes place during peaks in dune-building grass establishment, which depend on favorable environmental conditions. Our findings can potentially be integrated into beach restoration and management strategies.

Our research explores diverse ecosystems’ role in climate cooling via the concept of CarbonSink+ Potential. We measured CO₂ uptake and loaal aerosol production in forests, farms, peatlands, urban gardens, and coastal areas across Finland and Estonia. The long-term data reveal that while forests are vital regarding CarbonSink+ Potential, farms and urban gardens also play significant roles. These insights can help optimize management policy of natural resource to mitigate global warming.

How plants regulate their exchange of CO₂ and water with the atmosphere under global warming is critical for their carbon uptake and their cooling influence. We analyze the isotope ratio of atmospheric CO₂ and detect no significant decadal trends in the seasonal cycle amplitude. The data are consistent with the regulation towards leaf CO₂ and intrinsic water use efficiency to grow proportionally to atmospheric CO₂, in contrast to recent suggestions of downregulation of CO₂ and water fluxes.

Using Moderate Resolution Imaging Spectroradiometer data products, we quantitatively estimate the resistance and resilience of ecosystem functions to wildfires that occurred in the Columbia River Basin in 2015. Carbon state exhibits lower resistance and resilience than the ecosystem fluxes. The random forest feature importance analysis indicates that burn severity plays a minor role in the resilience of grassland, while it has a relatively major role in the resilience of forest and savanna.

Marine CO₂ removal (mCDR) is a promising technology for removing legacy emissions from the atmosphere. Its indirect nature makes it difficult to assess experimentally; instead one relies heavily on simulation. Many past papers treated the atmosphere as non-responsive to the intervention studied. We show that even under these simplified assumptions, the increase in ocean CO₂ inventory is equal to the equivalent quantity of direct CO₂ removals occurring over time, in a realistic atmosphere.

The ocean is a major natural carbon sink. Despite its importance, estimates of the ocean carbon sink remain uncertain. Here, I present a hybrid model estimate of the ocean carbon sink from 1959 to 2022. By combining ocean models in hindcast mode and Earth System Models, I keep the strength of each approach and remove the respective weaknesses. This hybrid model estimate is similar in magnitude than the best estimate of the Global Carbon Budget but 70 % less uncertain.

The vegetation can be used to infer the potential climate feedback of peatlands. New studies have shown recent expansion of peatlands but their plant community succession of has not been studied. Although generally described as dry bog-types, our results show that peatland margins in a subarctic fen initiated as wet fen with high methane emissions and shifted to dryer peatland types only after dryer post Little Ice Age climate. Thus, they have acted as a carbon source for most of their history.

Particulate organic nitrogen (PON) in the ocean refers to nitrogen contained in particles suspended such as phytoplankton, zooplankton, bacteria, viruses, and organic detritus. We used field measurements to determine relationships between PON and inherent optical properties of seawater across a broad range of marine environments. The presented relationships are expected to have application in the assessment of PON distribution and variations from in situ and satellite optical observations

Soil organic carbon models are used to predict how soils affect the concentration of CO₂ in the atmosphere. We show that equifinality – the phenomenon that different parameter values lead to correct overall model outputs, albeit with a different model behaviour – is an important source of model uncertainty. Our results imply that adding more complexity to soil organic carbon models is unlikely to lead to better predictions, as long as more data to constrain model parameters are not available.

We studied unique nitrate-rich soils in the hyperarid Atacama Desert that form brines at night under high relative humidity. Despite providing water for microorganisms, these soils exhibit extremely low microbial activity, indicating that the high nitrate levels inhibit microbial life. On the other hand, enriched organic matter indicates their potential preservation. This research helps to understand the limits of life in extreme environments and aids in the search for signs of life on Mars.

This study examines how microbial community structure, growth, and grazing impact the DOM pool in the Patagonian Shelf. Despite higher phytoplankton biomass, faster-growing bacteria were selectively grazed by protists leading to DOM accumulation, likely due to a reduction in DOM-consuming bacteria and the addition of egestion compounds. Experimental data showed that while bacteria remained as the primarily shapers of DOM quality, grazing pressure impacted on DOM accumulation.

A small fraction of particles found at great heights in the atmosphere can freeze cloud droplets at temperatures ≥ -10 °C and thus influence cloud properties. We provide a novel type of evidence that plant canopies are a major source of such biological ice nucleating particles in air above the Alps potentially affecting mixed-phase cloud development.

This study sought to explore organic-mineral interactions by investigating the functional performance of exposed clays through measurements of biogeochemical processes occurring on these materials. Results indicate that ancient clays are contributing to contemporary biogeochemical processes at ecosystem and landscape scales by supporting an active microbial community and a wide range of nitrogen cycle processes encompassing mineralization, immobilization, nitrification, and denitrification.

We present a novel method to quantify N₂ fixation by cyanobacteria, crucial in Baltic Sea eutrophication. Our Gas Equilibrium – Membrane-Inlet Mass Spectrometer (GE-MIMS), designed for operation on voluntary observing ships (VOS), enables large-scale monitoring of surface water N₂ depletion caused by N₂ fixation. Laboratory tests confirm the device’s accuracy and precision, ensuring it can complement current methods and contribute valuable data to better understand N₂ fixation in the Baltic Sea.

We intend to unravel iron (Fe) reduction pathways in high depositional methanic sediments because pools of Fe minerals could stimulate methane oxidation, but also generation. Our data from the North Sea indicate that Fe release takes place mechanistically different to Fe reduction in shallow sediments that typically fractionates Fe isotopes. We conclude that fermentation of organic matter involving interspecies electron transfer, partly through conductive Fe oxides, could play an important role.

To mitigate our impact on the climate, research suggests that we will need to both drastically reduce emissions and perform carbon dioxide removal (CDR). We simulated future climates under three emissions scenarios, in which we removed some carbon from the air and put it into agricultural soil at varying rates. We found that agricultural CDR is much more effective at reducing global temperatures if done in a low emissions scenario and at a high rate, and it becomes less effective with time.

Accurate radiation data are essential for understanding ecosystem growth. Traditional large-scale data lack the precision needed for complex terrains, e.g. mountainous regions. This study introduces a new model to enhance radiation data resolution using elevation maps, which accounts for sub-daily direct and diffuse radiation effects caused by terrain features. Tested on Mont Ventoux, this method significantly improves radiation estimates, benefiting forest growth and climate risk models.

The laws of physics show that leaf oxygen is not photosynthetically enriched, but extremely dilute due to the overwhelming effects of humidification. This challenges the prevailing diffusion-only paradigm regarding leaf gas exchanges, requiring non-diffusive transport. Such transport also explains why fluxes of carbon dioxide and water vapour become decoupled at very high temperatures, as has been observed but not explained by plant physiologists.

This article presents data on iron and manganese, which are essential micronutrients for primary producers, on the surface of the Arctic’s Laptev and East Siberian Seas (LESS). Observations were made in international cooperation with the NABOS expedition during the late summer of 2021 in the Arctic Ocean. The results from this study indicate that the major factors controlling these metal concentrations in LESS are river discharge and the input of shelf sediment.

We measured soil carbon fluxes during the first four years after a wildfire in the Swedish boreal forest. Soil CO₂ emissions decreased substantially only when trees were killed by fire or by post-fire logging, but not when trees survived the fire and were left standing. Soil methane flux was not affected by fire. Logging trees already killed by fire had no additional impact on soil carbon fluxes. Post-fire forest management strategy impacted vegetation regrowth and carbon dynamics.

This study analyzed marine sediment samples from areas with and without minimal hydrocarbon seepage from reservoirs underneath. Depth profiles of dissolved chemical components in the pore water as well as molecular biological data revealed differences in microbial community composition and activity. These results indicate that even minor hydrocarbon seepage affects sedimentary biogeochemical cycling in marine sediments, potentially providing a new tool for detection of hydrocarbon reservoirs.

In our study, we assessed the impact of olivine on marine primary producers of ocean-based solutions. The experiments revealed no negative effects on carbon fixation rates. Additions of the alkaline minerals did not establish growth inhibition; instead, they showed slight growth increases with species-specific responses. Ni exposure from olivine did not inhibit growth. However, limitations include the absence of responses in natural settings.

Mountain grasslands are impacted by Climate Change and need to adapt. Low mountain grasslands are poorly understood compared to High Mountains massif. Thanks to satellite archives, we found that grasslands occurring in the Vosges Mountains (France) exhibited stable productivity or tended to decrease in specific regions of the massif, a reverse signal observed in High Mountains massif. We also noted a high responsiveness in their growth strategy to soil moisture, snow regimes and topography.

Our results showed that crop development derived from satellite images was lower in a dry year compared to a normal year, and faster growth was found more important for higher biomass during drought. The magnitude of the drought impact differed between fields, where higher crop performance was related to more plant available water, suggesting that soil properties play a role in crop response to drought. Our results shows that satellite images can be used to assess plant-soil-weather interactions

Phytoplankton net primary production (NPP) is influenced by many processes, and their representation varies across Earth-system models. This leads to differing projections for NPP's future under climate change, especially in the North Atlantic. To address this, we identified and assessed the processes controlling NPP in each model. This assessment helped us select the most reliable models, significantly improving NPP projections in the region.

The open ocean helps mitigate climate change by storing CO₂ through the biological carbon pump (BCP). The BCP involves processes like phytoplankton capturing CO₂ and sequestering it in the deep ocean via marine snow production. We found significant marine snow accumulation from the surface to 600 meters deep in frontal regions between eddies. We suggest that the coupling of hydrodynamics at eddy edges and biological activity (via planktonic organisms) may enhanced this process.

The present study reports Fe-Mn-driven anaerobic oxidation of methane (Fe-Mn-AOM) in seasonally hypoxic coastal sediments under sulfidic conditions. The Fe-Mn-AOM activity is observed over the entire sediment core at multiple depths above and below the sulfate methane transition zone. We hypothesize that the focused Fe-Mn-AOM activity is possibly controlled by the Fe-Mn reducing microbial population distribution in the sediment core.

Gamma A is a widespread non-cyanobacterial diazotroph and plays a crucial role for marine ecosystems, but its controlling factors are still largely unknown. This study, for the  first time, quantified microzooplankton grazing on Gamma A and revealed significance of grazing pressure on Gamma A distribution around the Kuroshio region. It highlights the importance of top-down controls on Gamma A abundance and the associated nitrogen cycle.

The environmental factors and CO₂ flux of the grassland ecosystem in the dry-hot valley of the Jinsha River exhibited highly seasonal characteristics. During the rainy season, the grassland showed a carbon sink feature, while during the dry season, it exhibited carbon emission status. Throughout the entire year, the grassland ecosystem acted as a weak carbon source, exhibiting a carbon-neutral. The CO₂ flux was most influenced by vapor pressure deficit, relative humidity, and soil water content.

Coastal and shelf sediments are the most important sinks for organic carbon (OC) on Earth. We produced a new high-resolution sediment and pore-water dataset from the Helgoland Mud Area (HMA), North Sea, to determine, which depositional factors control the preservation of OC. The burial efficiency is highest in an area of high sedimentation and terrigenous OC. The HMA covers 0.09 % of the North Sea, but accounts for 0.76 % of its OC accumulation, highlighting the importance of the depocentre.

Intense grazing at grassland sites removes vegetation, reduces the snow cover, and inhibits litter layers from forming. Grazed sites generally have a larger annual ground surface temperature amplitude than ungrazed sites, but the net effect depends on effects in the transitional seasons. Our results also suggest that seasonal use of pastures can reduce ground temperatures, which can be a strategy to protect currently degrading grassland permafrost.

When microbes consume carbon within soils, it is important to know how much carbon is respired and lost as carbon dioxide versus how much is used to make new biomass. We used a new approach of monitoring carbon dioxide and oxygen to track the fate of consumed carbon during a series of laboratory experiments where sugar was added to moistened soil. Our approach allowed us to estimate how much sugar was converted to dead microbial biomass, which is more likely to be preserved in soils.

This study explores the impact of environmental conditions on the chemistry of coccoliths, calcite minerals produced by marine algae, to better understand past climate changes. By cultivating different species of coccolithophores under various CO₂ and pH levels, we have shown that the isotopic composition of certain species varies with CO₂ concentration and quantified these variations.

Here we present a comparison of results from the Mg/Ca and oxygen stable isotopes paleothermometers obtained from 57 modern to fossil species of planktonic foraminifera from the last 15 million of years. We find that the occurrence (or not) of species-species offsets in Mg/Ca is conservative between ancestor-descendent species, and that taking into account species kinship can significantly improve temperature reconstructions by several degrees.

Estuarine marshes are vital for capturing carbon and benefiting the climate. Our research explored how plant-microbe interactions affect carbon cycling, focusing on traits like root oxygen loss. Using a model, we found that accounting for these trait variations significantly changes carbon balance estimates. This suggests that including plant diversity in ecosystem models improves predictions about carbon dynamics in estuarine marshes, highlighting their importance in climate regulation.