This study presents measurements of carbon dioxide exchange between the atmosphere and a grazed savanna grassland ecosystem for 3 years. We find that the yearly variation in carbon dioxide balance is largely determined by the changes in the early wet season balance (September to November) and in the mid-growing season balance (December to January).

The paper demonstrates which different biological factors and physico-chemical processes are important regulators of soil isoprenoid emissions at different times of the year. With the obtained knowledge on soil VOC sources, it will be possible to add soil VOC production into air chemistry models and thus improve the understanding on climatic feedback mechanisms between secondary organic aerosol formation, clouds, and radiative forcing.

The alkylamines are important precursors in secondary aerosol formation in boreal forests. We quantified alkylamine concentrations in fungal species present in boreal forests in order to estimate soil as a source of atmospheric alkylamines. Based on our knowledge we estimated possible soil–atmosphere exchange of these compounds. The results shows that the boreal forest soil could act as a source of alkylamines depending on environmental conditions and studied compound.

Forest overstory and understory layers differ in carbon and water cycle regimes and phenology, as well as ecosystem functions. In this paper, overstory and understory LAI values were estimated separately for global needleleaf and deciduous broadleaf forests. This work would help us better understand the seasonal patterns of forest structure, evaluate the ecosystem functions and improve the modeling of the forest carbon and water cycles.

Peatlands are important because they sequester large amounts of carbon, for which nitrogen is needed. In peatlands dominated by peat mosses, atmospheric nitrogen is fixed by associated microorganisms. We here show for the first time experimentally that phosphorus availability and acid buffering, both showing large variations among peatlands, can explain the strong differences reported for nitrogen fixation. This improves our understanding of peatland functioning in relation to global change.

We ran a global ocean model to understand manganese (Mn), a biologically essential element. Our model shows that (i) in the deep ocean, dissolved [Mn] is mostly homogeneous ~0.10—0.15 nM. The model reproduces this with a threshold on MnO₂ of 25 pM, suggesting a minimal particle concentration is needed before aggregation and removal become efficient. (ii) The observed distinct hydrothermal signals are produced by assuming both a strong source and a strong removal of Mn near hydrothermal vents.

It is the first study to distinguish the species of nano-sized (d=1−20 nm), small-sized (d=20−450 nm) colloidal P, and dissolved P (d<1 nm) of hydromorphic surface grassland soils from Cambisol, Stagnic Cambisol to Stagnosol using FFF and ³¹P-NMR. Evidence of nano-sized associations of OC–Fe(Al)–PO₄³/pyrophosphate in Stagnosol. Stagnic properties affect P speciation and availability by releasing dissolved inorganic and ester-bound P forms as well as nano-sized organic matter–Fe/Al–P colloids.

Diatoms are one of the most important primary producers in highly productive coastal regions. Their silicified valves are susceptible to escape from the upper water column and be preserved in the sediment record, and thus are frequently used to reconstruct environmental conditions in the past from sediment cores. Here, we assess how water column diatom’s community in the NW Iberian coastal upwelling system is seasonally transferred from the surface to the seafloor sediments.

Soil respiration (R_s) is an important process where from living organisms (predominantly plants and microbes) emit carbon dioxide (CO₂) to the atmosphere. We show that a common explanation that R_s is controlled by temperature is oversimple and plant inputs are extremely important, causing the daily pattern of R_s to differ between crops. Measuring simultaneously at a single site will therefore not be a fair comparison; this must be considered in the design of future experimental comparisons.

Based on the analysis of precipitation collected at high altitude, this study provides a relevant advancement in the assessment of the major factors responsible for the abundance and variability of airborne bacterial cells and Pseudomonas syringae in relation to ice nucleators. This is of prime importance to obtain a better understanding of the impact of ice-nucleation-active organisms on the development of precipitation and to determine the dispersal potential of airborne microorganisms.

A high-resolution dynamical model was used to give the first simulation of the distribution of natural and anthropogenic radiocarbon (¹⁴C) across the whole Mediterranean Sea. The model correctly simulates the main features of ¹⁴C distribution during and after the bomb perturbation. The results demonstrate the major influence of the flux of Atlantic water through the Strait of Gibraltar, and a significant increase in ¹⁴C in the Aegean deep water during the Eastern Mediterranean Transient event.

As first study within my PhD with the general objective to improve and adapt remote sensing algorithms for the estimation of coloured dissolved organic matter (CDOM) content in lakes in a global scale, we carried out this set of measurements and experiments. This study gives us a better understanding of sources and variability in the optical properties of CDOM in lakes and how photobleaching controls and affects them.

This research describes a detailed analysis of current distributions of spring phytoplankton communities in the Labrador Sea based on 10 years of observations. Phytoplankton community composition varied mainly according to the contrasting hydrographical zones of the Labrador Sea. The taxonomic distinctions of these communities influenced the photosynthetic and biochemical signatures of near-surface waters, which may have a profound impact on the carbon cycle in high-latitude seas.

We investigate late Pleistocene permafrost at the Buor Khaya Peninsula (Laptev Sea, Siberia) for cryolithological, geochemical, and geochronological parameters. The sequences were composed of ice-oversaturated silts and fine-grained sands with 0.2 to 24 wt% of organic matter. The deposition was between 54.1 and 9.7 kyr BP. Due to coastal erosion, the biogeochemical signature of the deposits represents the terrestrial end-member, and is related to organic matter deposited in the marine realm.

We investigated the carbon (C) stock and net primary production (NPP) of early (ES) and late successional (LS) forest stands in a tropical montane forest (TMF) in Africa. The total C stock was 35% larger in LS compared to ES stands due to larger tree biomass, while NPP was similar. The results highlight the importance of accounting for disturbance regimes and differences in wood density and allometry between ES and LS tree species when quantifying C stock and sink strength of TMF.

The conventional method for determining dissolved inorganic carbon (DIC) and it carbon stable isotope ratio (δ¹³C–DIC) can be a laborious process which can limit sampling frequency. This paper presents a new approach to autonomously determine DIC & δ¹³C–DIC at high temporal resolution. The simple method requires no customised design. Instead it uses two commercially available instruments and achieved a sampling resolution of 16 mins with precision and accuracy comparable to conventional methods.

Vegetation growth in semi-arid regions is an important sink for human-induced fossil fuel emissions of CO₂ and this study addresses the strong need for improved understanding and spatially explicit estimates of CO₂ uptake by semi-arid ecosystems. We show that a model incorporating photosynthetic parameters upscaled using satellite-based earth observation simulates CO₂ uptake well for the Sahel, one of the largest semi-arid regions in the world.