The African baobab is a challenging climate and environmental archive for its semi-arid habitat due to dating uncertainties and parenchyma-rich wood anatomy. Annually resolved F¹⁴C data of tree-ring cellulose (1941–2005) from a tree in Oman show the annual character of the baobab’s growth rings but were up to 8.8 % lower than expected for 1964–1967. Subseasonal δ¹³C and δ¹⁸O patterns reveal years with low average monsoon rain as well as heavy rainfall events from pre-monsoonal cyclones.

Marine sand mining is becoming more and more important to nourish fragile coastlines that face global change. We investigated the largest sand extraction site in the German Bight. The study reveals that after more than 35 years of mining, the excavation pits are still detectable on the seafloor while the sediment composition has largely changed. The organic communities living in and on the seafloor were strongly decimated, and no recovery is observable towards previous conditions.

BrGDGT lipids are a proxy for temperature in lake sediments, but other parameters like pH can influence them, and seasonality can affect the temperatures they record. We find a warm-season bias at 43 new high-latitude sites. We also present a new method that deconvolves the effects of temperature, pH, and conductivity and generate global calibrations for these variables. Our study provides new paleoclimate tools, insight into brGDGTs at the biochemical level, and a new method for future study.

In this paper we quantify the subduction of upwelled nitrate due to physical processes on the order of several kilometers in the coastal upwelling off Peru and its effect on primary production. We also compare the prepresentation of these processes in a high-resolution simulation (~2.5 km) with a more coarsely resolved simulation (~12 km). To do this, we combine high-resolution shipboard observations of physical and biogeochemical parameters with a complex biogeochemical model configuration.

The Indian Ocean Rim hosts many of the underdeveloped and emerging economies that depend on ocean resources for the livelihood of millions. Operational ocean information services cater to the requirements of resource managers and end-users to efficiently harness resources, mitigate threats and ensure safety. This paper outlines existing tools and explores the ongoing research that has the potential to convert the findings into operational services in the near- to midterm.

The Arctic Ocean receives large amounts of river water rich in terrestrial dissolved organic matter (tDOM), which is an important component of the Arctic carbon cycle. Our analysis shows that mixing of three major freshwater sources is the main factor that regulates the distribution of tDOM concentrations in the Siberian shelf seas. In this context, the formation and melting of the land-fast ice in the Laptev Sea and the peak spring discharge of the Lena River are of particular importance.

We present long-term projections of global peatland area and carbon with a continuous transient history since the Last Glacial Maximum. Our novel results show that large parts of today’s northern peatlands are at risk from past and future climate change, with larger emissions clearly connected to larger risks. The study includes comparisons between different emission and land-use scenarios, driver attribution through factorial simulations, and assessments of uncertainty from climate forcing.

It is known that CO₂ fixation by photoautotrophic organisms is the major sink from the atmosphere. While biologists are aware that CO₂ fixation also occurs in heterotrophic organisms, this route of inorganic carbon, and its quantitative role, is hardly recognized in biogeochemistry. We demonstrate that a considerable amount of CO₂ is fixed annually through anaplerotic reactions in heterotrophic organisms, and a significant quantity of inorganic carbon is temporally sequestered in biomass.

The partitioning of evapotranspiration into evaporation from soil and transpiration from plants is crucial for a wide range of parties, from farmers to policymakers. In this work, we focus on a particular partitioning method, based on the stable isotopic analysis of water. In particular, we aim at highlighting the challenges that this method is currently facing and, in light of recent methodological developments, propose ways forward for the isotopic-partitioning community.

Microbes are the main drivers of productivity and nutrient cycling in the ocean. We present a combined approach assessing C and N uptake and microbial community diversity across ecological provinces in the Southern Ocean and southern Indian Ocean. Provinces showed distinct genetic fingerprints, but microbial activity varied gradually across regions, correlating with nutrient concentrations. Our study advances the biogeographic understanding of microbial diversity across C and N uptake regimes.

Microorganisms have the unique ability to form ice in clouds at relatively warm temperatures, especially specific types of plant bacteria. However, to date, members of the domain Archaea have not been evaluated for their cloud-forming capabilities. Here, we show the first results of Haloarchaea that have the ability to form cloud ice at moderate supercooled temperatures that are found in hypersaline environments on Earth.

In order to study the fate of litter nitrogen in forest soils, we combined a leaf litterfall exchange experiment using ¹⁵N-labeled leaf litter with long-term element budgets at seven European beech sites in Germany. It appears that fructification intensity, which has increased in recent decades, has a distinct impact on N retention in forest soils. Despite reduced nitrogen deposition, about 6 and 10 kg ha⁻¹ of nitrogen were retained annually in the soils and in the forest stands, respectively.

The width and the chemical signals of tree rings have the potential to test and improve the physiological responses simulated by global land surface models, which are at the core of future climate projections. Here, we demonstrate the novel use of tree-ring width and carbon and oxygen stable isotopes to evaluate the representation of tree growth and physiology in a global land surface model at temporal scales beyond experimentation and direct observation.

This study characterized the diversity of laboratory-produced charcoal morphological features of various fuel types from Siberia at different temperatures. The results obtained improve the attribution of charcoal particles to fuel types and fire characteristics. This work also provides recommendations for the application of this information to refine the past wildfire history.

In this study we analyse surface ocean dimethylsulfide (DMS) concentration and flux to the atmosphere from four CMIP6 Earth system models over the historical and ssp585 simulations. Our analysis of contemporary (1980–2009) climatologies shows that models better reproduce observations in mid to high latitudes. The models disagree on the sign of the trend of the global DMS flux from 1980 onwards. The models agree on a positive trend of DMS over polar latitudes following sea-ice retreat dynamics.

Along with current climate, vegetation, and human influences, long-term accumulation of biomass affects fires. Here, we find that including the influence of antecedent vegetation and moisture improves our ability to predict global burnt area. Additionally, the length of the preceding period which needs to be considered for accurate predictions varies across regions.

Raising the groundwater table (GWT) trough subsoil irrigation does not lead to a reduction of carbon emissions from drained peat meadows, even though there was a clear increase in the GWT during summer. Most likely, the largest part of the peat oxidation takes place in the top 70 cm of the soil, which stays above the GWT with the use of subsoil irrigation. We conclude that the use of subsoil irrigation is ineffective as a mitigation measure to sufficiently lower peat oxidation rates.

Cultured at in situ high-pressure conditions Cibicides and Cibicidoides taxa develop lasting ectoplasmic structures that cannot be retracted or resorbed. An ectoplasmic envelope surrounds their test and may protect the shell, e.g. versus carbonate aggressive bottom water conditions. Ectoplasmic roots likely anchor the specimens in areas of strong bottom water currents, trees enable them to elevate themselves above ground, and twigs stabilize and guide the retractable pseudopodial network.

Our new database summarizes DOC concentrations of 2167 water samples from 1833 lakes in permafrost regions across the Arctic to provide insights into linkages between DOC and environment. We found increasing lake DOC concentration with decreasing permafrost extent and higher DOC concentrations in boreal permafrost sites compared to tundra sites. Our study shows that DOC concentration depends on the environmental properties of a lake, especially permafrost extent, ecoregion, and vegetation.

A better understanding of past climate variations is essential to apprehend future climatic changes. The aim of this study is to investigate the applicability of specific organic compounds of bacterial origin, 3-hydroxy fatty acids (3-OH FAs), as temperature and pH proxies at the global level using an extended soil dataset. We show the major potential of 3-OH FAs as such proxies in terrestrial environments through the different models presented and their application for palaeoreconstruction.

Inland waters are usually not well restrained in terms of greenhouse gas measurements. One of these regions is the Danube Delta, Romania. Therefore, we measured continuously with sensors to collect high-resolution data for CH₄ and O₂ throughout the Delta. We found significant variation for all concentrations over the day and night and between regions, as well as large spatial variation throughout all regions, with large CH₄ concentrations flowing in from the reed beds to the lakes.