Future mining operations in the deep sea provide a source of scientific uncertainty and call for detailed study of the ecosystem. We investigated one of the most diverse and abundant taxa present in deep-sea sediments, nematodes, and demonstrate the importance of sediment attributes for their communities. Especially species that are less common and have a limited spatial distribution will be vulnerable to mining-induced changes. Our findings can serve as a reference for future impact studies.

Using very-high-resolution digital elevation models (DEMs), we assessed the basic structure and microtopographic variability of hummock–hollow plots at boreal and hemi-boreal sites primarily in North America. Using a simple model of peatland biogeochemical function, our results suggest that both surface heating and moss productivity may not be adequately resolved in models which only consider idealized hummock–hollow units.

The biological production and air–sea CO₂ exchange in the surface water of the northern Gulf of Mexico during springtime were mainly controlled by the changes in the availability of light and nutrients during the river–ocean mixing process, with strong CO₂ uptake occurring in the river plume regions. The slow air–sea CO₂ exchange rate and buffering effect of the CO₂ system may result in decoupling between biological production and CO₂ flux.

Run-of-the-river (ROR) reservoirs have reduced flooded areas that maintain natural river characteristics; however, little is known about their influence on carbon dioxide (CO₂) emission. In this regard, we evaluated the spatiotemporal CO₂ fluxes (FCO₂) and partial CO₂ pressure (pCO₂) of the Belo Monte hydropower complex. Our results emphasize that ROR dams contribute to CO₂) emissions. Only FCO₂ varies through reservoirs; in addition, both FCO₂ and pCO₂ are spatially heterogeneous.

Irrespective of variable environmental settings in estuaries, the quality of organic particles is an important factor controlling microbial processes that facilitate a reduction of land-derived nitrogen loads to the open sea. Through the interplay of biogeochemical processing, geomorphology, and hydrodynamics, organic particles may function as a carrier and temporary reservoir of nitrogen, which has a major impact on the efficiency of nitrogen load reduction.

In this study we tried to correlate Na / Ca ratios from cold-water corals with environmental parameters such as salinity, temperature and pH. We do not observe a correlation between Na / Ca ratios and seawater salinity, but we do observe a strong correlation with temperature. Na / Ca data from warm-water corals (Porites spp.) and bivalves (Mytilus edulis) support this correlation, indicating that similar controls on the incorporation of sodium exist in these aragonitic organisms.

The Antarctic Ice Sheet is considered a possibly important but largely overlooked source of iron (Fe). Here we explore its fertilization capacity by evaluating the response of marine biogeochemistry to Fe release from icebergs and ice shelves in a global ocean model. Large regional impacts are simulated, leading to only modest primary production and carbon export increases at the scale of the Southern Ocean. Large uncertainties are due to low observational constraints on modeling choices.

Using pathway analysis, we demonstrate that past aridity's effect is mediated by differential mechanisms for substrates of varied complexity. While microbial biomass plays a more important role in the decomposition of fresh litter, enzyme-catalyzed extracellular reactions predominantly govern the mineralization of SOC. Our findings have significant implications for assessing and modeling decomposition in different aridity regimes.

The carbon isotopes in algae can be used to predict food sources and environmental change. We explore how dissolved carbon is taken up by algae in the South Atlantic Ocean and how this affects their carbon isotope signature. We find that cell size controls isotope fractionation. We use our results to investigate how climate change may impact the carbon isotopes in algae. We suggest a shift to smaller algae in this region would decrease the carbon isotope ratio at the base of the food web.

We examined the effects of elevated CO₂, pine seedlings, and ectomycorrhizal fungi on mineral weathering. Seedlings significantly increased mineral weathering, while elevated CO₂ increased plant growth and organic acid concentrations but had no effect on weathering. Ectomycorrhial fungi showed some tendency to increase weathering. We conclude that nutrient uptake, which reduces transport limitation to weathering, is the primary mechanism by which plants enhanced weathering in this system.

Is the fraction of anthropogenically released CO₂ that remains in the atmosphere increasing? Is the rate at which the ocean and land sinks take up CO₂ from the atmosphere decreasing? We analyse these questions by means of a statistical dynamic multivariate model from which we estimate the unobserved trend processes together with the parameters that govern them. We find no statistical evidence of an increasing airborne fraction, but we do find statistical evidence of a decreasing sink rate.

A combination of gas chromatography and X-ray CT reveals the microscale processes that govern soil respiration. Aerobic and anaerobic respiration in microbial hotspots depends not only on the quality and quantity of soil organic matter, but also on the spatial distribution of hotspots. Denitrification kinetics are mainly governed by hotspot architecture due to local competition for oxygen during growth. Cumulative behavior is mainly governed by water saturation due to the overall supply with O₂.