Does numerical modelling of the onset of dissolution-convection reliably reproduce this key stabilization process in CO2 storage?

Dissolution of carbon dioxide into water is a key medium-term CO2 plume stabilization process. It proceeds much more quickly when aided by convection than when driven by diffusion alone. The onset of the convection process is not well understood, so laboratory experiments using a Hele-Shaw cell containing a porous medium were used to reproduce the process of CO2 dissolution and convection in water. High resolution numerical flow models were then used to replicate the laboratory results. They show a remarkably good match in terms of convective plume temporal and spatial development. This suggests that numerical models of dissolution-convection at much larger reservoir scales can reliably predict the onset of dissolution-convection

Development and testing of a risk indexing framework to determine field-scale critical source areas of faecal bacteria on grassland.

This paper draws on lessons from a UK case study in the management of diffuse microbial pollution from grassland farm systems in the Taw catchment, south west England. We report on the development and preliminary testing of a field-scale faecal indicator organism risk indexing tool (FIORIT). This tool aims to prioritise those fields most vulnerable in terms of their risk of contributing FIOs to water. FIORIT risk indices were related to recorded microbial water quality parameters (faecal coliforms [FC] and intestinal enterococci [IE]) to provide a concurrent on-farm evaluation of the tool. There was a significant upward trend in Log[FC] and Log[IE] values with FIORIT risk score classification (r2 =0.87 and 0.70, respectively and P<0.01 for both FIOs). The FIORIT was then applied to 162 representative grassland fields through different seasons for ten farms in the case study catchment to determine the distribution of on-farm spatial and temporal risk. The high risk fields made up only a small proportion (1%, 2%, 2% and 3% for winter, spring, summer and autumn, respectively) of the total number of fields assessed (and less than 10% of the total area), but the likelihood of the hydrological connection of high FIO source areas to receiving watercourses makes them a priority for mitigation efforts. The FIORIT provides a preliminary and evolving mechanism through which we can combine risk assessment with risk communication to end-users and provides a framework for prioritising future empirical research. Continued testing of FIORIT across different geographical areas under both low and high flow conditions is now needed to initiate its long term development into a robust indexing tool

Mitigating Greenhouse Gas and Ammonia Emissions from Swine Manure Management : A System Analysis

PMID: 28318241. We thank all our colleagues for their recommendations and support during this extensive study. Funding for the study was provided by the National Basic Research Program of China (2012CB417104), the Non-Profit Research Foundation for Agriculture (201303091), China Agriculture Research System (CARS-36), and UK-China Virtual Joint Centres on Nitrogen “N-Circle” and “CINAg” funded by the Newton Fund via UK BBSRC/NERC (BB/N013484/1 and BB/N013468/1, respectively).Peer reviewedPostprintPostprintPostprin

Competition for two sulphur containing amino acids (cysteine and methionine) by soil microbes and maize roots in the rhizosphere

The factors regulating potential acquisition of sulphur (S)-containing amino acids by plant roots from the rhizosphere remain poorly understood. Using radio tracer (14C and 35S), we studied the competition for two S-containing amino acids (i.e., cysteine (Cys) and methionine (Met)) within 24 hours (h), by the rhizosphere microbial community and maize plants (Zea mays L.). Our results showed that the capture of Cys and Met by the maize plants was much lower, with only &lt;10% of the added amino acid-14C or 35S captured by the plant, compared to the rhizosphere microbial community (76.9%) on average. We suggest that this could be a result of relatively high availability of inorganic N and S in soil solution, the lack of transmembrane for amino acids on maize root cells, as well as the rapid turnover of Cys and Met by soil microbes in the rhizosphere. The addition of inorganic S, significantly reduced plant capture of Cys and Met-14C by maize plants in the rhizosphere but had little effect on the capture of Cys and Met-35S (p&lt;0.05). Overall, our results imply that (1) Cys and Met are available carbon (C), nitrogen (N) and S sources for maize plants, potentially contributing to total plant N and S demand under certain conditions; (2) Utilization of Cys and Met by maize roots in the rhizosphere is independent of inorganic S availability; (3) Increased amino acid concentration led to higher capture by both plants and soil microbes, but had little effect on the competition success on either side