The northern Arabian Sea hosts a winter chlorophyll bloom, which exhibits strong interannual variability. The processes responsible for this interannual variation of the bloom are investigated using observations and a model. The interannual fluctuations of the winter bloom are largely related to the interannual mixed-layer depth (MLD) anomalies, which are driven by net heat flux anomalies. MLD controls the bloom amplitude through a modulation of nutrient turbulent fluxes into the mixed layer.

Transient global warming under the high emission scenario RCP8.5 is amplified by up to 6 % if a pH dependency of marine DMS production is assumed. Importantly, this additional warming is not spatially homogeneous but shows a pronounced north–south gradient. Over the Antarctic continent, the additional warming is almost twice the global average. In the Southern Ocean we find a small DMS–climate feedback that counteracts the original reduction of DMS production due to ocean acidification.

We studied the effects of summer heatwaves and drought on photosynthesis and isoprene emissions in black locust trees. While photosynthesis decreased, isoprene emission increased sharply during the heatwaves. Comparing isoprene emissions of stressed and unstressed trees at the same temperature, however, demonstrated that stressed trees emitted less isoprene than expected. This reveals that in order to predict isoprene emissions during heat waves, model parameters need to be re-evaluated.

Peatlands in the Pastaza–Maranon foreland basin in Peru, one of the largest peatland complexes in the Amazon basin, were found to be large sources of methane and may make important contributions to regional and global budgets of this greenhouse gas. Methane showed uneven seasonal trends in emissions, with some ecosystems emitting more methane during the dry season compared to the wet season.

Here we synthesize a wide range of global spatiotemporal observational data on carbon exchanges between the Earth surface and the atmosphere. A key challenge was to consistently combining observational products of terrestrial and aquatic surfaces. Our primary goal is to identify today’s key uncertainties and observational shortcomings that would need to be addressed in future measurement campaigns or expansions of in situ observatories.

Little information on the contribution of small-sized phytoplankton is currently available in the Amundsen Sea. Based on a strong negative correlation between the contributions of small phytoplankton and the total daily primary production of phytoplankton found in this study, we concluded that a potential decrease in total primary production would be led by increasing contribution of small phytoplankton in the Amundsen Sea under rapidly warming environmental conditions.

Boreal lakes and wetland ponds have pronounced impacts on the global methane cycle. During field campaigns to West Siberian lakes, strong variations in the methane flux on both local and regional scales were observed, with significant emissions from southern taiga lakes. A newly constructed process-based model helps reveal what controls this variability and on what spatial scales. Our results provide insights into the emissions and possible ways to significantly improve global carbon models.

Rivers draining small watersheds of the outer coastal Pacific temperate rainforest export some of the highest yields of dissolved organic carbon (DOC) in the world directly to the ocean. This DOC is largely derived from soils and terrestrial plants. Rainfall, temperature, and watershed characteristics such as wetlands and lakes are important controls on DOC export. This region may be significant for carbon export and linking terrestrial carbon to marine ecosystems.