Cobalt is a scarce nutrient required by phytoplankton. We report more than 800 measurements of dissolved cobalt in the South Pacific Ocean, which show high cobalt concentrations in anoxic subsurface waters offshore of Peru. Coastal cobalt sources may be stronger under low oxygen and could fluctuate as climate change is expected to alter the extent of these low-oxygen regions.

Enhanced analytical techniques were applied to characterize fossilized microbial cell membrane lipids from samples in the Tagus River basin spanning the last 6000 years. Using the novel methods and calibration, the pH estimates were improved upon, and this study reveals new factors that should be considered when using this proxy as well as affirms the importance of examining the provenance of these lipids before applying them for paleoclimate reconstructions.

Biochar-carrying hydrocarbon-degrading bacterial strains were used as a tool for remediation of oil-polluted soil. It was shown that amendment of oil-polluted soil by biochar causes acceleration of hydrocarbon decomposition compared with mixing and moistening. Inoculation of hydrocarbon-degrading bacteria on biochar may be recommended as an additional tool of remediation. New-generation sequencing methods were used to analyze how the microbial community changes in the process of bioremediation.

Nutrients from land have been discussed to increase eutrophication in the open sea. This model study shows that the coastal zone works as an efficient filter. Water depth and residence time regulate the retention that occurs mostly in the sediment due to processes such as burial and denitrification. On shorter timescales the retention capacity might seem less effective when the land load of nutrients decreases, but with time the coastal zone can import nutrients from the open sea.

Quantifying the carbon (C) stored within coastal sediments is key to improving our knowledge of the local and global C cycle. Here we present a new methodology to calculate the quantity of C held within coastal sediments. Through the application of this method to a mid-latitude fjord we have shown that a substantial quantity of C is held within these sediments. Additionally, we discovered that these sediments are more effective long-term stores of C than their terrestrial equivalents.

Cold-water corals form true hotspots of biodiversity in the cold and dark deep sea, but need to live off of only small amounts of food that reach the deep sea. Using chemical tracers, this study investigated whether cold-water corals are picky eaters. We found that under low food conditions, they do not differentiate between food sources but they do differentiate at high food concentrations. This adaptation suggests that they are well adapted to exploit short food pulses efficiently.

The land use sector (AFOLU) is a pivotal component of countries' mitigation commitments under the Paris Agreement. Global land use data are therefore important to complement and fill in countries' data gaps. But how different are the existing AFOLU datasets and why? Here we contrast six AFOLU datasets for the tropics at different levels of aggregation (spatial, gases, emission sources) and point out possible reasons for the observed differences and the next steps to improve land use emissions.

Considering air temperature as a direct predictor of heat stress is misleading as physiological consequences from heat depend on tissue temperatures. This study helps to clarify more fundamentally when and how heat waves may lead to plant stress by demonstrating how several environmental variables contribute to tissue temperatures. This renders it easier for ecologists and agronomists to predict when the dangers of heat stress occurring are highest.

Our work provides a new coral proxy-based reconstruction of sea surface temperature (SST) from the coral reefs of Rodrigues Island, located in the poorly studied south-central Indian Ocean trade wind belt. This site is well located to study the SST history of the subtropical Indian Ocean and its teleconnections with the Pacific over long timescales. Our results provide insights into biases in coral Sr / Ca-based SST reconstructions and how to avoid them.

It is unknown if lakes are important contributors to the total transfer of greenhouse gases between high Arctic regions and the atmosphere. We measured the transfer of carbon greenhouse gases between lakes and the atmosphere and compared results with adjacent landscapes. We found lakes were weak emitters of the gases to the atmosphere, compared to contributions of terrestrial ecosystems, and will likely continue to be inconsequential to regional carbon cycling in a warmer future climate.

Mesoscale eddies with very low–oxygen concentrations at shallow depth have been recently discovered in the eastern tropical North Atlantic. Our analysis shows that low oxygen eddies occur more frequent than expected and are found even close to the equator (8° N). From budget calculations we show that an oxygen reduction of 7 µmol/kg in the depth range of 50–150 m in the eastern tropical North Atlantic (peak reduction is 16 µmol/kg at 100 m depth) can be associated with the dispersion of these eddies.