With regard to global warming, an understanding of past temperature changes is becoming increasingly important. Branched glycerol dialkyl glycerol tetraethers (brGDGTs) are membrane lipids used globally to reconstruct lake water temperatures. In the Bale Mountains lakes, we find a unique composition of brGDGT isomers. We present a modified local calibration and a new high-altitude temperature reconstruction from the Horn of Africa spanning the last 12.5 kyr.

Ocean alkalinity enhancement has the capacity to remove vast quantities of carbon from the atmosphere, but its effect on marine ecosystems is largely unknown. We assessed the effect of increased alkalinity on a coastal phytoplankton community when seawater was equilibrated and not equilibrated with atmospheric CO₂. We found that the phytoplankton community was moderately affected by increased alkalinity and equilibration with atmospheric CO₂ had little influence on this effect.

We use a microbial ecosystem model to quantitatively explain the mechanisms controlling observed relative abundances and nitrification rates of ammonia- and nitrite-oxidizing microorganisms in the ocean. We also estimate how much global carbon fixation can be associated with chemoautotrophic nitrification. Our results improve our understanding of the controls on nitrification, laying the groundwork for more accurate predictions in global climate models.

Cleavage of proteins to smaller nitrogen compounds allows microorganisms and plants to exploit the largest nitrogen reservoir in soils and is considered the bottleneck in soil organic nitrogen cycling. Results from soils covering a European transect show that protein turnover is constrained by soil geochemistry, shifts in climate and associated alterations in soil weathering and should be considered as a driver of soil nitrogen availability with repercussions on carbon cycle processes.

The answer to how much carbon land ecosystems are projected to remove from the atmosphere until 2100 is different for each Earth system model. We find that differences across models are primarily explained by the annual land carbon sink dependence on temperature and soil moisture, followed by the dependence on CO₂ air concentration, and by average climate conditions. Our insights on why each model projects a relatively high or low land carbon sink can help to reduce the underlying uncertainty.

This article studies phytoplankton (microscopic plants in the ocean capable of photosynthesis) in Kong Håkon VII Hav in the Southern Ocean. Different species play different roles in the ecosystem, and it is therefore important to assess the species composition. We observed that phytoplankton blooms in this area are formed by large diatoms with strong silica armors, which can lead to high silica (and sometimes carbon) export to depth and be important prey for krill.

We seek to understand the influence of climatic seasonality and microtopography on CO₂ and CH₄ fluxes in an Amazonian mangrove. Topography and seasonality had a contrasting influence when comparing the two gas fluxes: CO₂ fluxes were greater in high topography in the dry period, and CH₄ fluxes were greater in the rainy season in low topography. Only CO₂ fluxes were correlated with soil organic matter, the proportion of carbon and nitrogen, and redox potential.

We focus on the exchange of key nutrients for algae production between the Arctic and Atlantic oceans through the Fram Strait. We show that the export of dissolved silicon here is controlled by the availability of nitrate which is influenced by denitrification on Arctic shelves. We suggest that any future changes in the river inputs of silica and changes in denitrification due to climate change will impact the amount of silicon exported, with impacts on Atlantic algal productivity and ecology.

Evaporation retrieval in heterogeneous ecosystems is challenging due to empirical estimation of ground heat flux and complex parameterizations of conductances. We developed a parameter-sparse coupled ground heat flux-evaporation model and tested it across different limits of water stress and vegetation fraction in the Northern/Southern Hemisphere. The model performed particularly well in the savannas and showed good potential for evaporative stress monitoring from thermal infrared satellites.

The amount of dissolved oxygen in the ocean is the result of interacting physical and biological processes. Oxygen vertical profiles show a subsurface maximum in a large part of the ocean. We used a numerical model to map this subsurface maximum in the Mediterranean Sea and to link local differences in its properties to the driving processes. This emerging feature can help the marine ecosystem functioning to be better understood, also under the impacts of climate change.

We investigate the spatial and temporal patterns of light and water limitation in plant function at the ecosystem scale. Using satellite observations, we characterize the nonlinear relationships between sun-induced chlorophyll fluorescence (SIF) and water and light availability. This study highlights that soil moisture limitations on SIF are found primarily in drier environments, while light limitations are found in intermediately wet regions.

The majority of river studies focus on headwater or floodplain systems, while often neglecting intermediate river segments. Our study on the subalpine Sihl River bridges the gap between streams and lowlands and demonstrates that moderately steep river segments are areas of significant instream alterations, modulating the export of organic carbon over short distances.