A three-dimensional solute transport model with biological reactions is presented for simulating the natural attenuation study (NATS) at the Columbus Air Force Base in eastern Mississippi. NATS consisted of the release of a petroleum-based nonaqueous phase liquid (NAPL) and subsequent monitoring of BTEX (benzene, toluene, ethylbenzene, p-xylene), naphthalene, decane, and bromide in a shallow, unconfined aquifer. Conceptual and mathematical models were developed for NAPL source release, sequential aerobic/anaerobic biodegradation, and sorption during NATS. A multiple species, solute transport code (SEAM3D) was used to simulate fully three-dimensional transport and aerobic, nitrate-reducing, ferrogenic, and methanogenic hydrocarbon biodegradation. Simulation results matched individual BTEX concentration distributions collected five- and nine-months following NAPL release. SEAM3D mass-balance calculations at t = nine months indicated that 49% of the hydrocarbon mass that dissolved into the aqueous phase was consumed by biodegradation, 13% of this mass was sorbed, and the remaining 38% was present in the aqueous phase. Mass calculations at t = nine months further indicated that aerobic biodegradation accounted for the majority of hydrocarbon biodegradation (46% of the biodegraded mass), followed by ferrogenesis (28%), nitrate-reduction (21%), and methanogenesis (5%). Model results were particularly sensitive to the NAPL release rate, the initial ferric iron (Fe[III]) concentration, hydrocarbon utilization rates, initial condition for the anaerobic microbial populations, and dispersivity.
Based on various experiences in developing Geodata Infrastructures (GDIs) for scientific applications, this article proposes the concept of a Scientific GDI that can be used by scientists in environmental and earth sciences to share and disseminate their research results and related analysis methods. Scientific GDI is understood as an approach to tackle the science case in Digital Earth and to further enhance e-science for environmental research. Creating Scientific GDI to support the research community in efficiently exchanging data and methods related to the various scientific disciplines forming the basis of environmental studies poses numerous challenges on today's GDI developments. The paper summarizes requirements and recommendations on the publication of scientific geospatial data and on functionalities to be provided in Scientific GDI. Best practices and open issues for governance and policies of a Scientific GDI are discussed and are concluded by deriving a research agenda for the next decade.
Enabling the integration of information provided by OGC Web Processing Services into geospatial massmarket applications is promising, as it increases the availability of information for most ordinary users. This information will be most likely based on the latest available data (e.g. collected by sensors) and can thereby support the user in time-constrained decisions. This paper presents an approach to actually configure and integrate such processes into geospatial massmarket applications. The applicability of the approach is demonstrated by a risk management scenario. The software presented has been developed within the Geoprocessing Community of the 52°North initiative and is available through an Open Source license.
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