Recent  

Currently people are very concerned about the vegetation changes and the driving factors, including natural and anthropogenic drivers. In this study, a general browning trend is found in Syria during 2001–2018 indicated by vegetation index. We found that land management caused by social unrest is the main cause of this browning phenomenon. The mechanism initially reported here highlights the importance of land management impacts at the regional scale.

The natural enrichment of Chloroflexi (Ktedonobacteria) at the Kilianstollen Marsberg copper mine rocks being exposed to the acidic sulfate rich leachate led to an investigation of eight metagenomically assembled genomes (MAGs) involved in copper and other transition heavy metal resistance in addition to low pH resistance and aromatic compounds degradation. The present study offers functional insights about a novel cold adapted Ktedonobacteria MAG extremophily along with other phyla MAGs.

Faecal biomarker analyses present a useful tool in geoarchaeological research. For a better understanding of the living of our ancestors in alpine regions, we investigated modern livestock faeces and Holocene soils on the prehistorical encampment site of Ullafelsen in the Fotsch Valley, Stubai Alps, Austria. First results show a high input of livestock faeces, while the input of human faeces are negligible for this archaeological site. Future studies focus on mire archives in the Fotsch Valley.

We investigate the effect of glacier meltwater on phytoplankton dynamics in Svalbard. Phytoplankton forms the basis of the marine food web, and its seasonal dynamics depend on the availability of light and nutrients, both of which are affected by glacier runoff. We use satellite ocean colour, an indicator of phytoplankton biomass, and glacier mass balance modelling, to find that the overall effect of glacier runoff on marine productivity is positive within the major fjord systems of Svalbard.

This paper uses a novel approach to quantify the impacts of the choice of decomposition model on carbon and nitrogen cycling. We compare the models to experimental data that examined litter decomposition over five different biomes. Despite widely differing assumptions, the models produce similar patterns of decomposition when nutrients are limiting. This differs from past analyses that did not consider the impacts of changing environmental conditions or nutrients.

• Zea mays grown in mesocosms with different soil nutrition levels • At low P availability leaf physiological activity initially decreased strongly • P stress decreased over the season • AMF symbiosis increased over the season • AMF symbiosis is most likely responsible for gradual reduction in P stress

In order to better reconstruct the geologic history of the North Water Polynya, we provide modern validations and calibrations of lipid biomarker proxies in Baffin Bay. We find that sterols, rather than HBIs, most accurately capture the current extent of the North Water Polynya and will be a valuable tool to reconstruct its past presence/absence. Our local temperature calibrations for alkenones, GDGTs and OH-GDGTs reduce the uncertainty present in global temperature calibrations.

Biodiversity is under threat from the effects of global warming. Assessing the effects of climate change on areas of high species richness is of high importance to conservation. Terrestrial and freshwater richspots have been and will be less affected by climate change than other areas. Marine richspots of biodiversity, however, are expected to experience more pronounced warming.

This study found climate to be a driving force for increasing per area emissions of greenhouse gases and removal of important nutrients from high latitude forests due to wildfire. It used detailed, direct measurements over a large area to uncover patterns and mechanisms of restructuring of forest carbon and nitrogen pools that are extrapolatable to larger regions. It also take a step forward in filling gaps in global knowledge of northern forest response to climate change strengthened wildfires.

Thawing of Arctic permafrost soils could trigger the release of vast amounts of carbon to the atmosphere, thus enhance climate change. Our study investigated how well the current network of eddy-covariance sites, a technique to monitor greenhouse gas exchange at local scales, captures pan-Arctic flux patterns. We identified large coverage gaps, e.g. in Siberia, but also demonstrated that a targeted addition of relatively few sites can significantly improve network performance.

The aim of this work is to explore the ability of the cyanobacterium Dolichospermum flosaquae in microbially-induced calcium carbonate precipitation (MICP). Environmentally, MICP controls the availability of calcium, carbon and phosphorus in freshwater lakes and carbon exchange with the atmosphere. Citrate, at 4 mg/L, induced the highest carbonate alkalinity, the highest calcium consumption, the highest urease activity along with the lowest photosynthetic and respiratory oxygen exchange.

Salt marshes are thought to be important carbon sinks because of their ability to store carbon in their soils. We provide the first estimates of how much blue carbon is stored in salt marshes on the Pacific Coast of Canada. We find that the carbon stored in the marshes is low compared to other marshes around the world, likely because of their young age. Still, the high marshes take up carbon at rates faster than the global average, making them potentially important carbon sinks in the future.

We investigated organic matter (OM) and plant wax-derived biomarkers in sediments and plants along the Mkhuze River to constrain OM's origin and transport pathways within South Africa's largest freshwater wetland. Presently, it efficiently captures OM, so neither transport from upstream areas nor export from the swamp occurs. Thus, we emphasize that such geomorphological features can alter OM provenance, questioning the assumption of watershed-integrated information in downstream sediments.

We present here, for the first time, simultaneously measured dimethylsulfide (DMS) seawater concentrations and DMS atmospheric mole fractions from the Peruvian upwelling region during two cruises in December 2012 and October 2015. Our results indicate low oceanic DMS concentrations and atmospheric DMS molar fractions in surface waters and the atmosphere, respectively. In addition, the Peruvian upwelling region was identified as an insignificant source of DMS emissions during both periods.

Permafrost thaw-driven landslides in the western Arctic are increasing organic carbon delivered to headwaters of drainage networks in the western Canadian Arctic by orders of magnitude. Through a series of laboratory experiments, we show that less than 10 % of this organic carbon is likely to be mineralized to greenhouse gases during transport in these networks. Rather most of the organic carbon is likely destined for burial and sequestration for centuries to millennia.

The amount of carbon dioxide (CO₂) being absorbed by the ocean is relevant to the earths climate. CO₂ values in the coastal ocean and estuaries are not well known because of the instrumentation used. We used a new approach to measure CO₂ across the coastal and estuarine zone. We found that CO₂ and salinity were linked to the state of the tide. We used our CO₂ measurements and model salinity to predict CO₂ draw down. Previous studies overestimate how much CO₂ the coastal ocean draw down.

This research shows strong indications that the age of the mangrove forest and its position from upstream to downstream along a delta play a vital role in the amount and sources of carbon stored in the mangrove sediments. Our findings also imply that carbon capture by the mangrove ecosystem itself contributes only partly and relatively little to long-term SOC storage. This finding is particularly relevant for budgeting the potential of mangrove ecosystems to mitigate climate change.

Forest environments contain a wide variety of airborne biological particles (bioaerosols) that are important for plant and animal health, and biosphere/atmosphere interactions. Using low-cost sensors and a FACE experiment, we monitor the impact of enhanced CO₂ on airborne particles. No effect of the enhanced CO₂ treatment on total particle concentrations was observed, but a potential suppression of high concentration bioaerosol events was detected under enhanced CO₂.

The origin and evolution of life does not contradict the laws of thermodynamics, but we have no proof that it is an inevitable consequence of these laws. We do not know if the first life arose under illumination or in darkness in the deep ocean or in the Earth's crust. We have no proof that it arose due to a "thermodynamic imperative of dissipating the prevailing solar spectrum", as there are other ways for entropy increase of solar radiation. The biosphere may, instead delay entropy production.

Coastal basins with high input of nutrients often suffer from oxygen deficiency. In summer 2018, the extent of oxygen depletion was exceptional in the Gulf of Riga. We analyzed observational data and found that extensive oxygen deficiency appeared since the water layer close to the seabed, where oxygen is consumed, was separated from the surface layer. The problem worsens if similar conditions restricting vertical transport of oxygen occur more frequently in the future.

Estuaries are key reactive ecosystems along the land–ocean aquatic continuum and are often strongly impacted by anthropogenic activities. We calculated nutrient in and out fluxes by using a 1-D transient model for seven estuaries along the French Atlantic coast. Among these, large estuaries with high residence times showed higher retention rates than medium and small ones. All reveal coastal eutrophication due to the excess of diffused nitrogen from intensive agricultural river basins.

We performed model simulations of vegetation change under historic and climate change scenarios at high spatial resolution. Projected treeline advance continued at the same or increased rates as during our historic simulation. Temperature isolines advanced faster than treelines, revealing a lag in potential vegetation shifts that was modulated by nitrogen availability. At year 2100 our projected treelines had advanced by 45 to 195 elevational meters depending on the scenario.