The investigation of water mass transport pathways and timescales is important to understand the global ocean circulation. Following earlier studies, we use artificial radionuclides introduced to the oceans in the 1950s to investigate the water transport in the subpolar North Atlantic (SPNA). For the first time, we combine measurements of the long-lived iodine-129 and uranium-236 to confirm earlier findings/hypotheses and to better understand shallow and deep ventilation processes in the SPNA.

It is of great interest to know whether croplands act as a net source or sink of atmospheric CO₂ and if soil carbon (C) stocks are preserved over long timescales due to the role of C in soil fertility. For a cropland in Switzerland it was found that managing the field under the Swiss framework of the Proof of Ecological Performance (PEP) resulted in soil C losses of 18.0%. Additional efforts are needed to bring Swiss management practices closer to the goal of preserving soil C in the long term.

During a French cruise in the northern North Atlantic Ocean in 2014, seawater samples were collected for dissolved Pb and Pb isotope analysis. Lead concentrations were highest in subsurface water flowing out of the Mediterranean Sea. The recently formed Labrador Sea Water (LSW) is much lower in Pb concentration than older LSW found in the West European Basin. Comparison of North Atlantic data from 1981 to 2014 shows decreasing Pb concentrations down to ~2500m depth.

As knowledge in biology and geology explodes, science becomes increasingly specialized. Given the overlap of the environmental sciences, however, the explosion in knowledge inevitably creates opportunities for interconnecting the biogeosciences. Here, 30 scientists emphasize the opportunities for biogeoscience collaborations across the world's remarkable long-term environmental research networks that can advance science and engage larger scientific and public audiences.

In the ocean, the availability of nitrogen is one of the most influential factors controlling primary productivity. Biological N₂ fixation, i.e., the reduction of atmospheric N₂ gas to biologically available ammonium, constitutes the major source of new N for the surface ocean. In this article, we reveal exceptionally high rates of N₂ fixation (among the highest over the world ocean) in the western tropical South Pacific, dominated by the cyanobacteria Trichodesmium.