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Non-deforestation fire vs. fossil fuel combustion: the source of CO2 emissions affects the global carbon cycle and climate responses

We simulated both fire pulses and stable fire regimes and found the resulting climatic impacts to be irreconcilable with equivalent amounts of CO2 emissions produced by fossil fuel combustion. Consequently, side-by-side comparisons of fire and fossil fuel CO2 emissions—implicitly implying that they have similar effects—should be avoided. Our study calls for the explicit representation of fire in climate models in order to improve our understanding of its impacts in the Earth system.

A multiproxy approach to understanding the “enhanced” flux of organic matter through the oxygen-deficient waters of the Arabian Sea

Drifting sediment traps were deployed in the oxygen-deficient waters of the Arabian Sea, where the sinking flux is less attenuated than in more oxic waters. Six mechanisms that might explain this “enhanced flux” were evaluated using literature and data. In the upper 500m, evidence was found supporting an oxygen effect and/or changes in the efficiency of the microbial loop, including the addition of chemoautotrophic carbon to the sinking flux.

Ideas and perspectives: Holocene thermokarst sediments of the Yedoma permafrost region do not increase the northern peatland carbon pool

We investigate the properties of soils and sediments in a particular and ancient Siberian permafrost landscape. We critically examine statements from a recent study that specific permafrost landforms affected by thawed permafrost (alases) in this region contain very large quantities of peat that previous studies had failed to include because of data set biases. We conclude that there is no evidence to suggest biases in existing data sets or that alas deposits increase the northern peatland pool.

Upwellings mitigated Plio-Pleistocene heat stress for reef corals on the Florida platform (USA)

We present stable isotope proxy data and calcification records from fossil reef corals. The corals investigated derive from the Florida carbonate platform and are of middle Pliocene to early Pleistocene age. From the data we infer an environment subject to intermittent upwelling on annual to decadal timescales. Calcification rates were enhanced during periods of upwelling. This is likely an effect of dampened SSTs during the upwelling.

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All-clear for gourmets: truffles not radioactive

Although ranging among the most expensive gourmet foods, it remains unclear whether truffles accumulate radioactivity at a harmful level comparable to other fungi. Insignificant radiocaesium concentrations in specimens from Switzerland, Germany, France, Italy, and Hungary provide an all-clear for truffle hunters and cultivators in Europe as well as dealers and customers from around the world.

Apparent increase in coccolithophore abundance in the subtropical North Atlantic from 1990 to 2014

In this study, we combine phytoplankton pigment data with particulate inorganic carbon and chlorophyll measurements from the satellite record to assess recent trends in phytoplankton dynamics in the North Atlantic subtropical gyre, with a focus on coccolithophores. We show that coccolithophores in the North Atlantic have been increasing in abundance. Correlations suggest that they are responding positively to increasing inorganic carbon from anthropogenic inputs in the upper mixed layer.

Runoff- and erosion-driven transport of cattle slurry: linking molecular tracers to hydrological processes

Our interdisciplinary research brings together methodologies from hydrology, soil science and biogeochemistry to address key questions about the transport of cattle slurry in the environment. The paper provides a novel approach to trace dissolved and particulate components of cattle slurry through an experimental hillslope system. This work provides one of the first examples of using biomarkers to assess the effects of slope gradient and rainfall intensity on the movement of slurry derived-OM.

Hidden biosphere in an oxygen-deficient Atlantic open-ocean eddy: future implications of ocean deoxygenation on primary production in the eastern tropical North Atlantic

The waters of the tropical Atlantic Open Ocean usually contain comparably high concentrations of oxygen. Now, it became clear that there are watermasses related to eddies that are nearly anoxic. We surveyed one of those eddies and found a biosphere that largely differed from the usual biosphere present in this area with a specific community responsible for primary production and for degradation processes. Further, we found the very first indication for active nitrogen loss in the open Atlantic.

Data-based estimates of the ocean carbon sink variability – first results of the Surface Ocean pCO2 Mapping intercomparison (SOCOM)

This study investigates variations in the CO2 uptake of the ocean from year to year. These variations have been calculated from measurements of the surface-ocean carbon content by various different interpolation methods. The equatorial Pacific is estimated to be the region with the strongest year-to-year variations, tied to the El Nino phase. The global ocean CO2 uptake gradually increased from about the year 2000. The comparison of the interpolation methods identifies these findings as robust.

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Reviews and syntheses: Effects of permafrost thaw on Arctic aquatic ecosystems

In this review, we give an overview of the current state of knowledge regarding how permafrost thaw affects aquatic systems. We describe the general impacts of thaw on aquatic ecosystems, pathways of organic matter and contaminant release and degradation, resulting emissions and burial, and effects on ecosystem structure and functioning. We conclude with an overview of potential climate effects and recommendations for future research.

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