Our paper provides a quantification of plastic pollution in the Mediterranean region and several policy scenario projections based on OECD (Organisation for Economic Co-operation and Development) data toward 2100. We estimate a 4-fold increase in Mediterranean marine plastic stock by 2060 and that the implementation of terrestrial plastic cleanup can significantly help to reduce plastic pollution transfer from land to sea. Our results provide insight for policymakers, which is needed at the regional scale in the context of the UNEP (United Nations Environment Programme) plastic treaty.

Seagrass restoration serves as a nature-based solution for carbon dioxide removal. We examined the organic carbon and carbonate dynamics of restored seagrass (SG) and bare sediment (BS) using ex situ core incubations. SG exhibited higher net ecosystem metabolism compared to BS, while no significant difference was observed in net ecosystem calcification. Consequently, SG demonstrated a significantly enhanced overall capacity for carbon uptake.

In the ocean, the potent greenhouse gas methane is largely produced – but also consumed – in coastal systems before reaching the atmosphere. Rising temperatures and shifting precipitation patterns will likely impact the community composition of aerobic methanotrophic bacteria (MOBs). Experiments with North Sea and Wadden Sea water showed that methane availability increased MOB abundance but that different MOB types could thrive under drastically changed environmental conditions.

We study how environmental variables influencing natural methane fluxes explain the seasonal variability in satellite-observed methane in Northern Hemisphere high-latitude wetland areas. Using two atmospheric model set-ups, we assess consistency with satellite data. Methane loss through reaction with hydroxyl radicals and links with snow cover, temperature, and snowmelt had the strongest influence. Our study highlights the value of satellite observations for understanding large-scale wetland emissions.

We analyse how Earth system models represent vegetation carbon flux variability in the Amazon. By assessing environmental factors influencing vegetation, we identified CO₂ fertilization, photosynthetic sensitivity to solar radiation and heterotrophic respiration as key sources of model uncertainty under climate change. We also identified a stronger El Niño–Southern Oscillation (ENSO)-driven temperature impact under global warming. Reducing these uncertainties will enhance the reliability of tropical carbon–climate projections.

We recorded three metrics of photosynthesis in the California Current. Real-time observations of microalgae physiology and productivity revealed signs of iron limitation where the continental shelf rapidly dropped off. Iron limitation influenced how efficiently light was absorbed and used for carbon fixation but did not appear to affect net photosynthetic oxygen production. Our results offer useful insights into efforts to model carbon fixation rates from microalgae optical properties.