Our research is the first approximation to understand the δ¹³C macroalgal variability in one of the most diverse marine ecosystems in the world, the Gulf of California. The life-form is the principal cause of δ¹³C macroalgal variability, mainly taxonomy. However, changes in habitat characteristics and environmental conditions also influence the δ¹³C macroalgal variability. The δ¹³C macroalgae is indicative of carbon concentration mechanisms and isotope discrimination during carbon assimilation.

Modeling vegetation canopy is important in predicting whether the land remains a carbon sink to mitigate climate change in the near future. Vegetation canopy model complexity, however, impacts the model-predicted carbon and water fluxes as well as canopy fluorescence, even if the same suite of model inputs is used. Given the biases caused by canopy model complexity, we recommend not misusing parameters inverted using different models or assumptions.

For the first time, this study presents the characteristics of primary production in coastal regions of the Mediterranean Sea based on satellite-borne observations for the period 2002–2016. The study concludes that there are significant spatial and temporal variations among different regions. Quantifying primary production is of special importance in the marine food web and in the sequestration of carbon dioxide from the atmosphere to the deep waters.

Metagenomic sequencing and freezing experiments of aerosol samples collected on Cyprus revealed rain-related short-term changes of bioaerosol and ice nuclei composition. Filtration experiments showed a rain-related enhancement of biological ice nuclei > 5 µm and < 0.1 µm. The observed effects of rainfall on the composition of atmospheric bioaerosols and ice nuclei may influence the hydrological cycle as well as the health effects of air particulate matter (pathogens, allergens).

This study identifies the most accurate biological proxy for the estimation of seawater pCO₂ fields, which are key to assessing the ocean carbon sink. Our analysis shows that the net community production (NCP), the balance between photosynthesis and respiration, was more accurate than chlorophyll a within a neural network scheme. The improved pCO₂ estimates, based on NCP, identified the South Atlantic Ocean as a net CO₂ source, compared to a CO₂ sink using chlorophyll a.

Heterotrophic marine bacteria are tiny organisms responsible for taking up organic matter in the ocean. Using a modeling approach, this study shows that characteristics (taxonomy and physiology) of bacteria are associated with a subset of ecological processes in the coastal West Antarctic Peninsula region, a system susceptible to global climate change. This study also suggests that bacteria will become more active, in particular large-sized cells, in response to changing climates in the region.

We monitor the spatio-temporal variability of organic and inorganic carbon (C) species in the tropical Nyong River (Cameroon), across groundwater and increasing stream orders. We show the significant contribution of wetland as a C source for tropical rivers. Thus, ignoring the river–wetland connectivity might lead to the misrepresentation of C dynamics in tropical watersheds. Finally, total fluvial carbon losses might offset ~10 % of the net C sink estimated for the whole Nyong watershed.

We evaluated a new diffusive soil probe integrated with high-resolution gas analyzers to measure soil gases in real time at a centimeter scale. Using columns with simple silica and soil, we captured changes in carbon dioxide (CO₂), volatile organic compounds (VOCs), and nitrous oxide (N₂O) with its isotopes to distinguish potential nutrient sources and microbial metabolism. This approach will advance the use of soil gases as important signals to understand and monitor soil fertility and health.

The bacterial mineralization of dissolved organic matter (DOM) in inland waters contributes to CO₂ emissions to the atmosphere. Human activities affect DOM sources. However, the implications on DOM mineralization are poorly known. Combining sampling and incubations, we showed that higher bacterial respiration in agro-urban streams related to a labile pool from aquatic origin. Therefore, human activities may have a limited impact on the net carbon exchanges between inland waters and atmosphere.

Anaerobic ammonium oxidation (anammox) is an important nitrogen-removal process in the ocean. We assess the distribution of bacteriohopanetetrol-x (BHT-x), used to trace past anammox, along a redox gradient in the water column of the Benguela upwelling system. BHT-x / BHT ratios of >0.18 correspond to the presence of living anammox bacteria and oxygen levels <50 μmol L⁻¹. This allows for a more robust application of BHT-x to trace past marine anammox and deoxygenation in dynamic marine systems.

Previous studies show that phytoplankton light absorption can warm the atmosphere, but how this warming occurs is still unknown. We compare the importance of air–sea heat versus CO₂ flux in the phytoplankton-induced atmospheric warming and determine the main driver. To shed light on this research question, we conduct simulations with a climate model of intermediate complexity. We show that phytoplankton mainly warms the atmosphere by increasing the air–sea CO₂ flux.

Long-term monitoring is needed to detect changes in our environment. Time series of ocean carbon have aided our understanding of seasonal cycles and provided evidence for ocean acidification. Data gaps are inevitable, yet no standard method for filling gaps exists. We present a regression approach here and compare it to seven other common methods to understand the impact of different approaches when assessing seasonal to climatic variability in ocean carbon.