Batch experiments were conducted to assess the biotransformation potential of four hydrocarbon monoterpenes (d-limonene, alpha-pinene, gamma-terpinene, and terpinolene) and four alcohols (arbanol, linalool, plinol, and alpha-terpineol) under aerobic conditions at 23 degrees C. Both forest-soil extract and enriched cultures were used as inocula for the biodegradation experiments conducted first without, then with prior microbial acclimation to the monoterpenes tested. All four hydrocarbons and two alcohols were readily degraded. The increase in biomass and headspace CO2 concentrations paralleled the depletion of monoterpenes, thus confirming that terpene disappearance was the result of biodegradation accompanied by microbial growth and mineralization. Plinol resisted degradation in assays using inocula from diverse sources, while arbanol degraded very slowly. A significant fraction of d-limonene-derived carbon was accounted for as non-extractable, dissolved organic carbon, whereas terpineol exhibited a much higher degree of utilization. The rate and extent of monoterpene biodegradation were not significantly affected by the presence of dissolved natural organic matter.

In laboratory microcosms using salt marsh soils and in field trials, it was possible to monitor and quantify crude oil mineralization by measuring changes in CO 2 δ 13 C signatures and the rate of CO 2 production. These values are easy to obtain and can be combined with simple isotope mass balance equations to determine the rate of mineralization from both the crude oil and indigenous carbon pool. Hydrocarbon degradation was confirmed by simultaneous decreases in alkane-, isoprenoid-, and PAH-hopane ratios. Additionally, the pseudo-first-order rate constants of alkane degradation (0.087 day -1 ) and CO 2 production (0.082 day -1 ) from oil predicted by the δ 13 C signatures were statistically indistinguishable. The addition of inorganic nitrogen and phosphate increased the rate of mineralization of crude oil in aerated microcosms but had no clear effect on in situ studies. This procedure appears to offer a means of definitively quantifying crude oil mineralization in a sensitive, inexpensive, and simple manner in environments with appropriate background δ 13 C signatures.

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A polycyclic aromatic hydrocarbon (PAH)-degrading culture enriched from contaminated river sediments and a Mycobacterium sp. isolated from the enrichment were tested to investigate the possible synergistic and antagonistic interactions affecting the degradation of pyrene in the presence of low molecular weight PAHs. The Mycobacterium sp. was able to mineralize 63% of the added pyrene when it was present as a sole source of carbon and energy. When the enrichment culture and the isolated bacterium were exposed to phenanthrene, de novo protein synthesis was not required for the rapid mineralization of pyrene, which reached 52% in chloramphenicol-treated cultures and 44% in the absence of the protein inhibitor. In the presence of chloramphenicol, < 1% of the added pyrene was mineralized by the mixed culture after exposure to anthracene and naphthalene. These compounds did not inhibit pyrene utilization when present at the same time as pyrene. Concurrent mineralization of pyrene and phenanthrene after exposure to either compound was observed. Cross-acclimation between ring classes of PAHs may be a potentially important interaction influencing the biodegradation of aromatic compounds in contaminated environments.

SummaryMilitary bases resemble small cities and face similar sustainability challenges. As pilot studies in the U.S. Army Net Zero program, 17 locations are moving to 100% renewable energy, zero depletion of water resources, and/or zero waste to landfill by 2020. Some bases target net zero in a single area, such as water, whereas two bases, including Fort Carson, Colorado, target net zero in all three areas. We investigated sustainability strategies that appear when multiple areas (energy, water, and waste) are integrated. A system dynamics model is used to simulate urban metabolism through Fort Carson's energy, water, and waste systems. Integrated scenarios reduce environmental impact up to 46% from the 2010 baseline, whereas single-dimension scenarios (energy-only, water-only, and wasteonly) reduce impact, at most, 20%. Energy conserving technologies offer mutual gains, reducing annual energy use 18% and water use 15%. Renewable energy sources present trade-offs: Concentrating solar power could supply 11% of energy demand, but increase water demand 2%. Waste to energy could supply 40% of energy demand and reduce waste to landfill >80%, but increase water demand between 1% and 22% depending on cooling system and waste tonnage. Outcomes depend on how the Fort Carson system is defined, because some components represent multiple net zero areas (food represents waste and energy), and some actions require embodied resources (energy generation potentially requires water and off-base feedstock). We suggest that integrating multiple net zero goals can lead to lower environmental impact for military bases. Keywords:industrial ecology military renewable energy system dynamics urban metabolism water recycling Supporting information is available on the JIE Web site

Microbial community dynamics in wetlands microcosms emended with commercial products (surfactant, a biological agent, and nutrients) designed to enhance bioremediation was followed for 3 months. The effectiveness of enhanced degradation was assessed by determining residual concentrations of individual petroleum hydrocarbons by GC/MS. The size and composition of the sediment microbial community was assessed using a variety of indices, including bacterial plate counts, MPNs, and DNA hybridizations with domain- and group-specific oligonucleotide probes. The addition of inorganic nutrients was the most effective treatment for the enhancement of oil degradation, resulting in marked degradation of petroleum alkanes and a lesser extent of degradation of aromatic oil constituents. The enhanced degradation was associated with increases in the amount of extractable microbial DNA and Streptomyces in the sediment, although not with increased viable counts (plate counts, MPN). Bacteria introduced with one of the proprietary products were still detected in the microcosms after 3 months, but were not a major quantitative constituent of the community. The biological product enhanced oil degradation relative to the control, but to a lesser extent than the nutrient additions alone. In contrast, application of the surfactant to the oil-impacted sediment decreased oil degradation.

Like many urban areas around the world, Durham and Orange counties in North Carolina, USA are experiencing population growth and sprawl that is putting stress on the transportation system. Light rail and denser transit-oriented development are being considered as possible solutions. However, local agencies and stakeholders are concerned the light rail may worsen housing affordability and have questioned whether investment in both light rail and dense redevelopment are necessary to achieve community goals. We developed an integrated system dynamics model to quantitatively explore the outcomes of these land use and transportation options across multiple societal dimensions. The model incorporates feedbacks among the land, transportation, economic, equity, and energy sectors. This paper uses the results of four model scenarios, run between 2000 and 2040, to address two main questions: (1) what role does redevelopment play in capturing the socioeconomic benefits of transit infrastructure investment? And (2) how do redevelopment and light-rail transit interact to affect housing and transportation affordability? We find that transit investment and dense redevelopment combine synergistically to better achieve the goals of the light-rail line, including economic development, mobility, and compact growth. However, housing affordability does worsen in the combined scenario, as transportation-cost savings are not sufficient to offset the rise in housing costs. We emphasize that model users may input their own assumptions to explore the dynamics of alternative scenarios. We demonstrate how spatially-aggregated systems models can complement traditional land use and transportation models in the regional planning process.

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