Sugar compounds in air can trace the source of bioaerosols that affect public health and climate. In rural north China, we observed increased fungal activity at night and less variable bacterial community diversity. Certain night-increasing sugar compounds were more closely related to fungi than bacteria. The fungal community greatly influenced sugar compounds, while bacteria played a limited role. Caution is advised when using sugar compounds to trace airborne microbes, particularly bacteria.

After heavy pollution in the 1980s, a long-term inorganic carbon increase in the Elbe Estuary (1997–2020) was fueled by phytoplankton and organic carbon production in the upper estuary, associated with improved water quality. A recent drought (2014–2020) modulated the trend, extending the water residence time and the dry summer season into May. The drought enhanced production of inorganic carbon in the estuary but significantly decreased the annual inorganic carbon export to coastal waters.

This study found the source of dissolved organic carbon and its optical properties (e.g., aromaticity, humification) are related to human land use and catchment slope in anthropogenically impacted subtropical mountainous rivers. The study highlights that the combination of dual carbon isotopes and optical properties represents a useful tool in tracing the origin of dissolved organic carbon and its in-stream processes.

Fatty alcohols (FAs) are major components of surface lipids in plant leaves and serve as surface-active aerosols. Our study on the aerosol size distributions in a forest suggests that secondary FAs (SFAs) originated from plant waxes and that leaf senescence status is likely an important factor controlling the size distribution of SFAs. This study provides new insights into the sources of primary biological aerosol particles (PBAPs) and their effects on the aerosol ice nucleation activity.

We studied the impact of submarine canyon processes within the Pointe-des-Monts system on biogenic matter export and phytoplankton assemblages. Using data from three oceanographic moorings, we show that the canyon experienced two low-amplitude sediment remobilization events in 2020–2021 that led to enhanced particle fluxes in the deep-water column layer > 2.6 km offshore. Sinking phytoplankton fluxes were lower near the canyon compared to background values from the lower St. Lawrence Estuary.

Seawater naturally contains trace metals such as Mo and U, which accumulate under low oxygen conditions on the seafloor. Previous studies have used sediment Mo and U contents as an archive of changing oxygen concentrations in coastal waters. Here we show that in fjords the use of Mo and U for this purpose may be impaired by additional processes. Our findings have implications for the reliable use of Mo and U to reconstruct oxygen changes in fjords.

Agricultural landscapes act as sinks or sources of the greenhouse gases (GHGs) CO₂, CH₄, or N₂O. Various physicochemical and biological processes control the fluxes of these GHGs between ecosystems and the atmosphere. Therefore, fluxes depend on environmental conditions such as soil moisture, soil temperature, or soil parameters, which result in large spatial and temporal variations of GHG fluxes. Here, we describe an example of how this variation may be studied and analyzed.

This paper presents novel results of laboratory-produced charcoal forms from various grass, forb and shrub taxa from the Eurasian steppe to facilitate more robust interpretations of fuel sources and fire types in grassland-dominated ecosystems. Advancements in identifying fuel sources and changes in fire types make charcoal analysis relevant to studies of plant evolution and fire management.

We present an analysis of soil CO₂ emissions in boreal and tundra regions during the non-growing season. We show that when the soil is completely frozen, soil temperature is the main control on CO₂ emissions. When the soil is around the freezing point, with a mix of liquid water and ice, the liquid water content is the main control on CO₂ emissions. This study highlights that the vegetation–snow–soil interactions must be considered to understand soil CO₂ emissions during the non-growing season.

The sinking of zooplankton fecal pellets is a key process in the marine biological carbon pump. This study presents carbon export of four shapes of fecal pellets from two time-series sediment traps in the South China Sea. The results show that the sinking fate of fecal pellets is regulated by marine primary productivity, deep-dwelling zooplankton community, and deep-sea currents in the tropical marginal sea, thus providing a new perspective for exploring the carbon cycle in the world ocean.

Twenty tropical tree species native to Africa were planted along an elevation gradient (1100 m, 5.4 °C difference). We found that early-successional (ES) species, especially from lower elevations, grew faster at warmer sites, while several of the late-successional (LS) species, especially from higher elevations, did not respond or grew slower. Moreover, a warmer climate increased tree mortality in LS species, but not much in ES species.

Ocean acidity extremes in the upper 250 m depth of the northeastern Pacific rapidly increase with atmospheric CO₂ rise, which is worrisome for marine organisms that rapidly experience pH levels outside their local environmental conditions. Presented research shows the spatiotemporal heterogeneity in this increase between regions and depths. In particular, the subsurface increase is substantially slowed down by the presence of mesoscale eddies, often not resolved in Earth system models.

Our study focuses on one of the most used microfossils in paleoenvironmental reconstructions: foraminifera. We set up a novel approach of long-term cultures under variable and controlled conditions. Our results highlight that foraminiferal tests can be used as a unique record of both SO₄²⁻/CaCO₃ and δ³⁴S seawater variation. This establishes geological formations composed of biogenic carbonates as a potential repository of paleoenvironmental seawater sulfate chemical and geochemical variation.

Methane produced by microorganisms in subsurface environments may account for a large fraction of global natural gas reserves. To understand how microbial methane is produced during sediment burial history, we examined methane-bearing aquifers in which temperature and salinity increase with depth. Geochemical and microbiological analyses showed that microbial methane is produced at depth, where microbial activity is stimulated by the increased temperature, and subsequently migrates upwards.

Internal and external sources of organic carbon (OC) in lakes can contribute to oxygen depletion, but their relative contributions remain in question. To study this, we built a two-layer model to recreate processes relevant to carbon for six Wisconsin lakes. We found that internal OC was more important than external OC in depleting oxygen. This shows that it is important to consider both the fast-paced cycling of internally produced OC and the slower cycling of external OC when studying lakes.

This study adapts the Rock-Eval® protocol to quantify soil organic carbon (SOC) and soil inorganic carbon (SIC) on a non-pretreated soil aliquot. The standard protocol properly estimates SOC contents once the TOC parameter is corrected. However, it cannot complete the thermal breakdown of SIC amounts > 4 mg, leading to an underestimation of high SIC contents by the MinC parameter, even after correcting for this. Thus, the final oxidation isotherm is extended to 7 min to quantify any SIC amount.