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The Chinese subtropical forest ecosystems are an extremely important component of those global forest ecosystems and are hence crucial for the global carbon cycle and regional climate change. However, there is still a great uncertainty in the relationship between subtropical forest carbon sequestration and its drivers. Here, we provided the first quantitative estimates of the individual and interactive effects of different drivers on the GPP of various subtropical forest types in China.

Organic matter and microbial fluid analyses are rarely taken into account in the geothermal industry and research. However, they can have a significant effect on the efficiency of geothermal power production. We discovered a high variety in organic compound composition in our samples and were able to differentiate it with regard to various sources (e.g. artificial and biogenic). Furthermore, the microbial diversity undergoes significant changes within the flow path of a geothermal power plant.

In summer 2019, the Northwest Passage Project explored the Canadian Arctic Archipelago (CAA). Our study revealed methane oversaturation in upper CAA waters, driven by meltwater, turbidity, and specific microbial activity. It highlights the need to distinguish active methane zones. Western CAA showed higher methane activity, while the east had lower levels due to Atlantic Water influence. These findings contribute to understanding Arctic methane dynamics and its climate change implications.

To keep the Paris agreement goals within reach, negative emissions will be necessary. They can be achieved with mitigation techniques such as reforestation that remove CO₂ from the atmosphere. While governments have pinned their hopes on them, there is not yet a good set of tools to objectively determine whether negative emissions do what they promise. Here we show how satellite measurements of plant fluorescence are useful in detecting carbon uptake by reforestation and vegetation regrowth.

Coastal marine sediments are subject to major acidification processes because of climate change and human activities, but these processes can also result from biotic activity. We studied the cable bacteria activity effect on benthic calcareous foraminifera in intertidal mudflats. The strong pH decrease in sediments caused by these bacteria leads to the calcareous test dissolution of living and dead foraminifera, threatening the test preservation and their robustness as bioindicators or proxies.

We integrated observations essential for policy decisions with high-resolution 3D model results to improve the reliability of oxygen assessments. Based on our findings, we suggest merging only high temporal and/or vertical resolution station data with model data to increase confidence in oxygen assessments. While showing the strengths and limitations of our approach we show that model simulations are an useful tool for policy-relevant oxygen assessments.

This study contrasts seabed food webs between a river-fed, high-energy canyon and the nearby slope. We show higher organic carbon (OC) flows through the canyon than the slope. Bacteria dominated the canyon, while seabed fauna contributed more to the slope food web. Due to frequent perturbation, the canyon had a lower faunal stock and OC recycling. Only 1 % of the seabed OC flux enters the canyon food web, suggesting a significant role of the river-fed canyon in transporting OC to the deep sea.

We inoculated wheat plants with various types of fungi whose impacts on soil carbon are poorly understood. After several months of growth, we examined both their impacts on soil carbon and the underlying mechanisms, using multiple methods. Overall, the fungi benefited the storage of carbon in soil mainly by improving the stability of pre-existing carbon, but several pathways were involved. This study demonstrates their importance for soil carbon storage and, therefore, climate change mitigation.

The coastal ocean in northeastern USA provides many services, including fisheries and habitat for threatened species. In summer 2019, a bloom occurred of an unusual large phytoplankton, the diatom Hemiaulus with nitrogen fixing symbionts. This led to vast changes in productivity and grazing rates in the ecosystem. This work shows that the emergence of one species can have profound effects on ecosystem function. Such changes maybe become more prevalent as the ocean warms due to climate change.

Ocean alkalinity enhancement (OAE) aims to increase atmospheric CO₂ sequestration in the oceans by spreading ground alkaline materials into the ocean. To assess the environmental impacts of OAE, we used 53 L microcosms to test how coastal plankton communities respond to OAE with olivine or steel slag as alkalinity sources. Overall, steel slag is much more efficient for CO₂ removal than olivine and appears to be induce less changes in the phytoplankton and zooplankton communities.

Wildfires have wide-ranging consequences for local communities, air quality and ecosystems. Vegetation amount and moisture state are key components to forecast wildfires. We developed a combined model and satellite framework to characterise vegetation, including the type of fuel, whether it is alive or dead, and its moisture content. The daily data is at high resolution globally (~9 km). Our characteristics correlate with active fire data and can inform fire danger and spread modelling efforts.

Representing socio-economic impacts on fires is crucial to underpin the confidence in global fire models. Introducing these into INFERNO, reduces biases and improves the modelled burnt area (BA) trends when compared to observations. Including socio-economic factors in the representation of fires in Earth System Models is important for realistically simulating BA, quantifying trends in the recent past, and for understanding the main drivers of those at regional scales.

Understanding the link between climate and carbon fluxes is crucial in predicting how climate change will impact carbon sinks. We estimated CO₂ fluxes from deadwood in tropical Australia using wood microclimate variables (wood moisture content and temperature). Our model predicted that the majority of deadwood carbon is released as CO₂, except when termite activity is detected. Future models should also incorporate wood traits, like species and chemical composition, to better predict fluxes.

Ocean alkalinity enhancement (OAE) is a promising method of atmospheric carbon removal, however it's ecological impacts remain largely unknown. We assessed the effects of simulated silicate and calcium based mineral OAE on diatom silicification. We found that increased silicate concentrations from silicate based OAE increased diatom silicification. In contrast, the enhancement of alkalinity had no effect on community silicification and minimal effects on the silicification of different genera.

The Fennoscandian boreal and mountain regions harbour a wide range of ecosystems sensitive to climate change. A new, highly resolved high-emission climate scenario enabled modelling of the vegetation development in this region at high resolution for the 21^st century. The results show dramatic south to north and low to high altitude shifts of vegetation zones, especially for the open tundra environments, that will have large impli-cations for nature conservation, reindeer husbandry and forestry.

Current and future nitrous oxide (N₂O) emissions are difficult to estimate due to their high variability in space and time. Several years of N₂O fluxes from drained boreal peatland forest indicate high importance of summer precipitation, winter temperature and snow conditions in controlling annual N₂O emissions. The results indicate increasing year-to-year variation in N₂O emissions in changing climate with more extreme seasonal weather conditions.

We explored the relationship between oxygen and stratification in the North Pacific Ocean, using a combination of data mining and machine learning. We used isopycnic potential vorticity (IPV) as an indicator to quantify ocean ventilation and we analyzed its predictability, a strong O₂-IPV connection and predictability for IPV in the tropical Pacific. This open new routes to monitor ocean O₂ through few observational sites co-located with more abundant IPV measurements in the tropical Pacific.

Along the French coast facing the Bay of Biscay, the two main estuaries, the Gironde and the Loire, experience hypoxia, motivating this study of the small Charente estuary between them. This work highlights a minimum oxygen zone in the Charente estuary extending for about 25 km, temperature being the main factor controlling the hypoxia. This calls for the monitoring of small highly turbid macrotidal estuaries vulnerable to hypoxia, a risk that will increase with global warming.

Swings in Amazon forest greenness were observed during the 2015/16 drought, but no satisfactory explanation has been found. We, based on water storage, temperature and atmospheric moisture demand, developed a method to delineate the regions where forests were under stress. These drought-affected regions were mainly identified at the beginning and end of the drought, resulting in below-average greenness. For the months in between without stress, greenness responded positively to strong sunlight.

Crystalline rock cores down to 2250 m depth, groundwater-bearing fractures, and the drilling fluid were sampled for DNA to characterise the subsurface microbial community. In general, microbial biomass was extremely low, despite the employment of detection methods widespread in low-biomass environments. The described contamination control measures could support future sampling efforts and our findings emphasize the use of sequencing extraction controls.

From glacial headwaters to 100 km downstream, we found clear organic matter gradients in Canadian Rocky Mountain rivers. In contrast, microbial communities exhibited overall cohesion, indicating that species dispersal may be an over-riding control on community dynamics in these connected rivers. Identification of glacial-specific microbes suggest that glaciers seed headwater microbial communities; these findings show the importance of glacial waters and microbiomes in changing mountain systems.

We present an integrative model approach that is based on plant water potential triggering stomatal closure, downregulation of photosynthesis, and sapwood as well as foliage senescence. This new model functionality that can be added to any physiologically based ecosystem model has been evaluated in an extremely dry Aleppo pine plantation. We were able to represent gas exchanges under varying soil water supply and atmospheric demand and the model responded realistically regarding leaf senescence.

Our research highlights the effectiveness of a recurrent neural network, LSTM, in predicting plant carbon absorption using weather and satellite data. LSTM outperforms other models, even for new locations, suggesting its broad application. Yet, challenges remain in predicting diverse ecosystems globally due to varying plant and climate factors. Our work enhances understanding of Earth's complex ecosystems using advanced models.

Permafrost soils contain twice the amount of carbon than the atmosphere, and its release could majorly affect global temperatures. This study found that a thicker moss layer resulted in cooler temperatures deeper in the soil, despite warmer surface temperatures. The top green living moss layer was the most important in regulating the soil temperatures and should be considered when predicting the response of permafrost thaw to climate change.

During an investigation on the effects that bottom-trawling, we found that otter boards that keep the nets open, burry surface sediment at a few centimeters sediment depth. This is also done by animals living in the sediment and the process is considered very important for sediment ecosystem integrity. We try to differentiate between the two and estimate that natural bioturbation is much more likely than otter board sediment reversal in OUR sediment areas.

Algal biomarkers were used to assess sea ice and pelagic algal production across the western Arctic Ocean with changing sea ice conditions. They show three distinct areas along with a marked latitudinal gradient of sea ice over pelagic algal production in surface sediments that are reflected by the H-print index. Our data also show that efficient grazing consumption accounted for the dramatic decrease of diatom derived biomarker in sediments compared to that of particulate matter.

The SOC molecular structure suggested that the easily decomposable and stabilized SOC are similarly affected after 9-year warming and N treatments despite the large changes in SOC stocks. Given the long residence time of some SOC, the similar loss of all measurable chemical forms of SOC under global change treatments could have important climate consequences.

We report taxon-specific biogeography of N₂-fixing microbes (diazotrophs) driven by Kuroshio intrusion (KI) into the South China Sea. We show that the composition and distribution of distinct diazotrophic taxa shift with KI-induced variations in physicochemical parameters of seawater, and that KI shapes diazotrophic community as primarily a stochastic process. This study thus has implications for the redistribution of diazotrophs in a future warming ocean as KIs are projected to intensify.

Gross primary productivity (GPP) describes the photosynthetic carbon assimilation, which plays an important role in the carbon cycle. We can measure GPP locally, but it is challenging to produce larger and continuous estimates. Here, we present an approach to extrapolate GPP to a global scale using satellite imagery and automated machine learning. We benchmark different models and predictor variables and achieve an estimate that can capture 75 % of the variation in GPP.

The amount of carbon that forests gain from the atmosphere, called net primary productivity (NPP), changes a lot with age. These forest NPP-age relationships could be modelled from field survey data, but we're not sure which model works the best. Here we tested five different models using 3121 field survey samples in China, and the Semi-Empirical Mathematical (SEM) function was determined as the best. The built relationships by SEM can improve China's forest carbon modelling and prediction.

This study explored year-round forest-floor greenhouse gas (GHG) fluxes in a Swiss spruce forest. CO₂ emissions were influenced by soil temperature and snow depth, while CH₄ uptake related to snow cover. Negligible N₂O fluxes were observed. In 2022, a warm year, CO₂ emissions notably increased. The study suggests rising forest-floor GHG emissions due to climate change, impacting carbon sink behavior. Thus, for future forest management, continuous year-round GHG flux measurements are crucial.

Higher evaporation in peatlands has been predicted due to climatic drying. We determined whether the water-conservative vegetation at a Southern Hemisphere bog could cause a different response to dryness compared to a 'typical' Northern Hemisphere bog, using decades-long evaporation datasets from each site. At the southern bog, evaporation increased at a much lower rate with increasing dryness, suggesting that this peatland type may be more resilient to climate warming than northern bogs.