In the southern parts of the Sierra Nevada in California, we investigated erosion of carbon and nitrogen from low-order catchments. We found that eroded sediments were OM rich, with a potential for significant gaseous and dissolved loss of OM during transport or after depositional in downslope or downstream depositional landform positions.

The Arctic Ocean is considered the most vulnerable ecosystem to ocean acidification (OA), but very little information is available on natural variability of pH in the Arctic coastal zone. We report pH variability at various scales in a Greenland fjord. Variability ranged up to 0.2-0.3 pH units horizontally and vertically in the fjord, between seasons and on diel basis in kelp forests and was extreme in tidal pools. Overall, primary producers played a fundamental role in producing mosaics of pH.

We show that the fundamental molecules of life (those common to all three domains of life: Archaea, Bacteria, Eukaryota), including nucleotides, amino acids, enzyme cofactors, and porphyrin agglomerates, absorb light strongly from 230 to 280nm (in the UV-C) and have chemical affinity to RNA and DNA. This supports the "thermodynamic dissipation theory for the origin of life", which suggests that life arose and evolved as a response to dissipating the prevailing Archaean UV-C sunlight into heat.

Calcification by marine organisms reacts to changing seawater carbonate chemistry, but it is unclear which components of the carbonate system drive the observed response. This study uncovers proportionalities between different carbonate chemistry parameters. These enable us to understand why calcification often correlates well with carbonate ion concentration, and they imply that net CaCO3 formation in high latitudes is not more vulnerable to ocean acidification than formation in low latitudes.

Coastal wetlands vegetated by common reed and rice paddies emit significant amounts of methane to the atmosphere whereas sea-blite marshes are net sinks for atmospheric methane. The main controlling factors for the methane emissions are water table, temperature, soil organic carbon and salinity. The methane emissions from coastal wetlands can be reduced by creating fluctuating water tables, including water tables below the soil surface, as well as by occasional flooding by high-salinity water.

A tiny fraction of marine algae escapes decomposition and is buried in sediments. Since tools are needed to track the fate of algal organic carbon, we tested whether naturally occurring isotope variability among amino acids from algae and bacteria can be used as source diagnostic fingerprints. We found that isotope fingerprints track algal amino acid sources with high fidelity across different growth conditions, and that the fingerprints can be used to quantify bacterial amino acids in sediment.

There has been growing interest in quantifying the capacity of seagrass ecosystems to act as carbon sinks as a natural way of offsetting anthropogenic carbon emissions to the atmosphere. However, most of the efforts have focused on the organic fraction and ignored the inorganic carbon pool. This study offers the first global assessment of PIC stocks and accumulation rates in seagrass sediments, identifying these ecosystems as important contributors to carbonate dynamics in coastal areas.

The spatiotemporal variability in the vertical distribution of the chlorophyll concentration in the Mediterranean Sea is investigated. Results are based on a large database of fluorescence profiles intercalibrated from ocean color satellite data. They indicate that two types of chlorophyll seasonality coexist in the Mediterranean Sea. The shape of the chlorophyll profile is very dynamic during winter, and the deep chlorophyll maximum is a dominant feature of Mediterranean chlorophyll profile.

We demonstrate and explain differential patterns in SOM dynamics in C3/C4 mixed ecosystems at various spatial scales across contrasting climate and soils. This study shows that the interdependence between biotic and abiotic factors ultimately determines whether SOM dynamics of C3- and C4-derived vegetation are at variance in ecosystems where both vegetation types coexist. The results also highlight the far-reaching implications that vegetation thickening may have for the stability of deep SOM.

We compared monthly leaf area index (LAI) estimates from the Community Land Model (CLM) in stress/drought deciduous regions of the world to a satellite-derived estimate of LAI. This comparison revealed an issue in the CLM in which leaves begin to grow during the dry season due to unrealistic soil water movement. We introduced a rainfall trigger to the stress deciduous algorithm to address this issue, then showed the impacts of this change on the fire cycle and stored carbon.

POC fluxes obtained in the Eastern Beaufort Sea in August 2009 from drifting sediment traps were low (1-15 mg C m-2d-1), compared to long-term data which show higher but variable fluxes (10-40 mg C m-2d-1). Composition of sinking particles, especially faecal pellets, highlighted the role of the zooplankton community and its trophic structure in the transition of carbon from the productive surface zone to the deep ocean. Carbon flux at this season results from a heterotrophic driven ecosystem.

Light absorption by colored detrital material (CDM) was included in a fully coupled Earth system model. Chlorophyll and biomass increased near the surface but decreased at greater depths when CDM was included. Concurrently, total biomass decreased leaving more nutrients in the water. Regional changes were analyzed by comparing the competing factors of diminished light availability and increased nutrient availability on phytoplankton growth.

Soil respiration and its stable isotopes were studied in a subalpine forest. There was strong diel variability in soil efflux but not in the isotope content of soil efflux or CO2 from biological activity in the soil. Following rain, soil efflux increased, but the isotope content of these fluxes did not change. Temporal variation in the isotope content of soil efflux was unrelated to environmental variables. Results confirmed established theory regarding diffusive soil gas transport.