Recent  

We are among the first to quantify methane emissions from wetlands and lakes in the pan-Arctic. The total CH₄ emissions are 35.81 Tg CH₄ yr⁻¹ during 2000–2015, of which wetlands and lakes were 21.38 Tg yr⁻¹ and 14.45 Tg yr⁻¹, respectively. By using 2 non-overlap area change datasets combined with land and lake models, our simulation avoids some small lakes being counted twice as both lake and wetland, and narrows the gap between two different methods that used to quantify regional CH₄ emission.

This study explores how the representation of leaf phenology affects our ability to predict changes to the carbon balance of land ecosystems. We calibrate a new leaf phenology model against a diverse range of observations at six forest sites, showing that it improves the predictive capability of the processes underlying the ecosystem carbon balance. We then show how changes in temperature and rainfall affect the ecosystem carbon balance with this new model.

Data on past relative humidity (RH) is needed to improve its representation in Earth system models. A new isotopic parameter of silica formed in plants is developed to reconstruct quantitatively past RH. By comprehensive monitoring and using novel methods, we show how environmental, and plant physiological parameters influence the isotopic composition and formation rates of plant silica. The insights gained from this study help to improve estimates of RH from fossil plant silica deposits.

This study demonstrates, based on morphological attributes of coccolitophores, that dissolution effects primarily affect the morphology of coccoliths preserved in the deep ocean. In the South China Sea surface sediments, bottom water calcite saturation plays a major role in the variation of the coccoliths' shape factor (ks), which has the potential, based on the current calibration, to quantitatively reconstruct past carbonate dissolution changes.

Total alkalinity (TA) is the oceanic capacity to store CO₂. Estuaries can be a source for TA, by producing it by e.g., anaerobic metabolic pathways like denitrification (reduction of NO₃- to N₂), a major nitrogen (N) sink. Another important N sink is anammox, which transformes NH₄⁺ with NO₂- into N₂. By combining TA and N₂ production, we identified a TA source, denitrification occurring in the water column, and suggest anammox as the dominant N₂ producer in the bottom layers of the Ems Estuary.

Afforestation and reducing fossil fuel emissions are two important mitigation strategies to reduce the amount of global warming. Our work shows that reducing fossil fuel emissions is relatively more effective than afforestation for the same amount of carbon removed from the atmosphere. However, both afforestation and reduction in fossil fuel emission should be pursued simultaneously to mitigate climate change and reduce ocean acidification.

Eighty Ma old fossil leaf assemblages suggest a widespread distribution of tropical rainforest in north-eastern Africa.

Carbonyl Sulfide (COS) is a useful constraint on photosynthesis. To simulate COS leaf flux better in the SiB4 model, we propose a new temperature function for the enzyme carbonic anhydrase (CA) and optimize conductances using observations. CA has an optimum temperature below 40 °C, which can be influenced critically by air temperature changes. It brings tropics a smaller and higher latitudes a larger uptake. This update helps resolve gaps in the COS budget identified in earlier studies.

Managing drinking water catchments to minimise water colour could reduce costs to water companies and save their customers money. Brown coloured water comes from peat soils, primarily around upland reservoirs. Management practices including blocking drains, removing conifers, restoring peatland plants and reducing burning have been used to try and reduce water colour. This work brings together the published evidence for the effectiveness of these practices to aid water industry decision making.

Satellite-based analysis illustrates the impact of geological processes on the functionality and stability of the ecosystem in the Mara River Basin (Kenya/Tanzania). Newly detected fault activity influences the course of river networks and modifies erosion-deposition patterns, and tectonic surface features and variations in rock chemistry lead to localized enhancement of clay and soil moisture values and seasonally stabilised vegetation growth patterns in this climatically vulnerable region.

This is the first study of the current and future impacts of climate change on Pacific oyster farming in Japan. Future coastal warming and acidification may affect oyster larvae, as a result of longer exposure to lower pH waters. A prolonged spawning period may harm oyster processing by shortening the shipping period and reducing oyster quality. To minimize impacts on Pacific oyster farming, in addition to mitigation measures, local adaptation measures may be required.

Gelatinous zooplankton play a key role in the ocean carbon cycle. In particular, pelagic tunicates, which feed on a wide size range of preys, produce rapidly sinking detritus. Thus, they efficiently transfer carbon from the surface to the depth. Consequently, we added these organisms to a marine biogeochemical model (PISCES-v2) and evaluated their impact on the global carbon cycle. We found that they contribute significantly to carbon export, and that this contribution increases with depth.

Large numbers of marine organisms such as zooplankton and fish perform daily vertical migration between the surface (during nighttime) and the depths (during daytime). This fascinating migration is important for the carbon cycle, as these organisms actively bring carbon to depths, where it is stored away from the atmosphere for a long time. Here, we quantify the contributions of different animals to this carbon draw-down and storage, and show that fish are important to the biological carbon pump

This study investigated the molecular composition and carbon dioxide production of water samples collected from two subarctic rivers that represent contrasting types of catchment characteristics. The results highlight the role of clearwater environments in microbial degradation and greenhouse gas dynamics of subarctic catchments.

We use a reactive continuum model based on a lognormal distribution (l-RCM) to inversely determine model parameters μ and σ at 123 sites across the global ocean. Our results show organic matter (OM) reactivity is more than three orders of magnitude higher in shelf than that in abyssal regions. In addition, OM reactivity is higher than predicted in some specific regions, yet the l-RCM can still capture OM reactivity features in these regions.

This study found source of dissolved organic carbon and optical properties (e.g., aromaticity, humification) are related with human land uses and catchment slope in anthropogenically-impacted subtropical mountainous rivers. This study highlights that the combination of dual carbon isotopes and optical properties are useful tools in tracing the origin of dissolved organic carbon and its in-stream processes.

This work quantifies the impact of optically significant water constituents on surface heating rates and thermal energy fluxes in the Western Baltic Sea. During productive months in 2018 (April to September), we found that the combined effect of CDOM and particulate absorption contributes to sea surface heating of between 0.4 and 0.9 K m^-1 d^-1 and a mean loss of heat (c. 5 Wm^-2) from the sea to the atmosphere. This result may be important for regional heat balance budgets.

The Rhodes Gyre, located in the eastern Mediterranean Sea, is the main Levantine Intermediate Water formation site. In this study, we use a 3D physical-biogeochemical model to investigate the seasonal and interannual variability of organic carbon dynamics in the gyre. Our results show its autotrophic nature and its high interannual variability with enhanced primary production, downward and onward exports to the surrounding regions during years marked by intense heat losses and deep mixed layers.

Glacier forefields have long provided ecologists with a model to study patterns of plant succession following glacier retreat. We used remote sensing approaches to study early succession dynamics as it allows to analyze the deglaciation, colonisation and vegetation growth within a single framework. We found that the heterogeneity of early succession dynamics is deterministic and can be well explained by local environmental context. This work has been done by an international consortium.

Drained peatlands (peat areas where ditches have been excavated to enhance crop productivity) are one of the main sources of carbon dioxide emissions globally. Blocking the ditches by building dams is a common strategy to raise the water table and to mitigate carbon dioxide emissions. But how effective is ditch-blocking in raising the overall water table? Our work tackles this question by making use of the available data and physics-based hydrological modeling.

One of the least well understood processes in the nitrogen (N) cycle is the loss of nitrogen gas (N₂), referred to as total denitrification. This is mainly due to the difficulty of quantifying total denitrification in situ. In this study, we developed and tested a novel modeling approach to estimate total denitrification over the depth profile, based on concentrations and isotope values of N₂O. Our method will help close N budgets and identify management strategies that reduce N pollution.

Deep convection plays a key role in the circulation, thermodynamics and biogeochemical cycles in the Mediterranean Sea, considered as a hotspot of biodiversity and climate change. In this study, we investigate the seasonal cycle and annual budget of dissolved inorganic carbon in the deep convection area of the northwestern Mediterranean Sea.

Emerging molecular methods provide new ways of understanding how marine communities respond to changes in ocean conditions. Here, environmental DNA was used to track the temporal evolution of biological communities in the Peruvian coastal upwelling system and in an adjacent enclosure where upwelling was simulated. We found that the two communities quickly diverged, with the open ocean being one found during upwelling and the enclosure evolving to one found under stratified conditions.

Understanding terrestrial sources of nitrogen is vital to examine lake eutrophication changes. Combining process-based ecosystem modeling and satellite observations, we found that land-leached nitrogen in the Yangtze Plain significantly increased from 1979 to 2018 and terrestrial nutrient sources were positively correlated with eutrophication trends observed in most lakes, demonstrating the necessity of sustainable nitrogen management to control eutrophication.

We quantified how microbial respiration is controlled by discharge and the supply of C, N, and P in a stream. We ran two rounds of experiments adding a conservative tracer, an indicator of aerobic respiration, and nutrient treatments: a) N, b) N+C, c) N+P, and d) C+N+P. Microbial respiration remained similar between rounds and across nutrient treatments, suggesting that both exposure times and nutrient composition control microbial metabolic activity in stream ecosystems.

We show, for the first time, that pure cultures of the cyanobacterium Microcystis aeruginosa can synthesize the potent greenhouse gas N₂O using nitrite as substrate. Our findings have broad environmental implications because M. aeruginosa is globally found in freshwater ecosystems and is often the dominant species found in algae blooms. Further research is now needed to determine the occurrence and significance of N₂O emissions from ecosystems rich with M. aeruginosa.