We present leaf wax n-alkanes and their compound-specific (CS) δ¹³C isotopes from semi-arid and/or arid Mongolia to test their potential for paleoenvironmental reconstructions. Plants and topsoils were analysed and checked for climatic control. Chain-length variations are distinct between grasses and Caragana, which are not biased by climate. However CS δ¹³C is strongly correlated to climate, so n-alkanes and their CS δ¹³C show great potential for paleoenvironmental reconstruction in Mongolia.

We examined the effects of season and tree harvesting on the flow of water and the organic carbon (OC) it carries from boreal forest soils. We found that more OC was lost from the harvested forest because more precipitation reached the soil surface but that during periods of flushing in autumn and snowmelt a limit on the amount of water-extractable OC is reached. These results contribute to an increased understanding of carbon loss from boreal forest soils.

Novel filamentous cable bacteria that grow in the top layer of intertidal mudflat sediment were attracted to electrodes poised at a positive electrical potential. Several diverse morphologies of Desulfobulbaceae filaments, cells, and colonies were observed on the electrode surface. These observations provide information to suggest conditions that will induce cable bacteria to perform electron donation to an electrode, informing future experiments that culture cable bacteria outside of sediment.

Phytoplankton are an essential component of the marine food web and earth's carbon cycle. We use observations, ecological theory and a unique trait-based ecosystem model to explain controls on patterns of marine phytoplankton biodiversity. We find that different dimensions of diversity (size classes, biogeochemical functional groups, thermal norms) are controlled by a disparate combination of mechanisms. This may explain why previous studies of phytoplankton diversity had conflicting results.

The Arctic picoeukaryote Micromonas pusilla was acclimated to two pCO₂ levels under a constant and a dynamic light, simulating more realistic light fields. M. pusilla was able to benefit from ocean acidification with an increase in growth rate, irrespective of the light regime. In dynamic light M. pusilla optimised its photophysiology for effective light usage during both low- and high-light periods. This highlights M. pusilla is likely to cope well with future conditions in the Arctic Ocean.

Today, sterols are widespread in plants, animals, and fungi but are almost absent in the oldest rocks. Microbial mats, representing the earliest complex ecosystems on Earth, were omnipresent in Precambrian marine environments and may have degraded the sterols at that time. Here we analyze the distribution of sterols through a microbial mat. This provides insight into how variations in biological and nonbiological factors affect the preservation of sterols in modern and ancient microbial mats.

Natural and restored wetlands typically emit methane to the atmosphere. However, we found that a wetland constructed after oil sand mining in boreal Canada using organic soils from local peatlands had negligible emissions of methane in its first 3 years. Methane production was likely suppressed due to an abundance of alternate inorganic electron acceptors. Methane emissions may increase in the future if the alternate electron acceptors continue to decrease.

Biogeochemical processes of SOM are key for greenhouse gas emission and water quality. We extracted SOM by water or by NaOH–HCl under oxic–anoxic conditions. Chemical and anoxic extractions lead to higher SOM electron exchange capacities, resulting in stimulation of microbial Fe(III) reduction. Therefore, aqueous pH-neutral SOM extracts should be used to reflect environmental SOM redox processes, and artifacts of chemical extractions need to be considered when evaluating SOM redox processes.

This paper presents a study of the CO₂ fluxes in a pine forest plantation at the dry timberline in the Negev, combining the present time with the long-term perspective. Two key issues that limit our understanding are the need to know the sources of CO₂ fluxes and the need for long-term perspectives. We provide evidence that helps explain the forest plantation productivity under stressful conditions, which can assist in predicting the response of forest to future drying climate.

Soil is the largest carbon pool in forests. Whether forest soils function as a sink or source of atmospheric carbon remains controversial. Here, we investigated the 20-year changes in the soil organic carbon pool at eight permanent forest plots in China. Our results revealed that the soils sequestered 3.6–16.3  % of the annual net primary production across the investigated sites, demonstrating that these forest soils have functioned as an important C sink during the past 2 decades.

We studied the role of plant species groups in peatland methane fluxes under natural conditions and lowered water level. At a natural water level, sedges and mosses increased the fluxes. At a lower water level, the impact of plant groups on the fluxes was small. Only at a high water level did vegetation regulate the fluxes. The results are relevant for assessing peatland methane fluxes in a changing climate, as peatland water level and vegetation are predicted to change.

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Soil respiration (R_s) is the flow of CO₂ from the soil surface to the atmosphere and is one of the largest carbon fluxes on land. This study examined the effect of local basal area (tree area) on R_s in a coastal forest in eastern Maryland, USA. R_s measurements were taken as well as distance from soil collar, diameter, and species of each tree within a 15 m radius. We found that trees within 5 m of our sampling points had a positive effect on how sensitive soil respiration was to temperature.

Climate change severely impacts grassland carbon cycling, especially in arid ecosystems, such as desert steppes. The current results highlight the great dependence of soil carbon emission on warming regimes of different duration and the important role of precipitation pulse during growing season in assessing the terrestrial ecosystem carbon balance and cycle.

Measurements of phytoplankton health still require the use of research vessels and are thus costly and sparse. In this paper we propose a new way to assess the health of phytoplankton using simple fluorescence measurements, which can be made autonomously. In the Southern Ocean, where the most limiting nutrient for phytoplankton is iron, we found a relationship between iron limitation and the depression of fluorescence under high light, the so-called non-photochemical quenching of fluorescence.

The influence of climate signals in the Pacific, especially the Pacific Decadal Oscillation and the North Pacific Gyre Oscillation, as well as El Niño–La Niña and an 18.6-year nodal tidal cycle on oxygen and nutrient trends is investigated. At different locations in the Pacific Ocean different climate signals dominate. Hence, not only trends related to warming but also the influence of climate signals need to be investigated to understand oxygen and nutrient changes in the ocean.