http://hdl.handle.net/10379/139 Sun, 29 Oct 2017 22:37:03 GMT 2017-10-29T22:37:03Z http://hdl.handle.net/10379/6846 Bumblebee colony development following chronic exposure to field-realistic levels of the neonicotinoid pesticide thiamethoxam under laboratory conditions Stanley, Dara A.; Raine, Nigel E. Neonicotinoid pesticides are used in agriculture to reduce damage from crop pests. However, beneficial insects such as bees can come into contact with these pesticides when foraging in treated areas, with potential consequences for bee declines and pollination service delivery. Honeybees are typically used as a model organism to investigate insecticide impacts on bees, but relatively little is known about impacts on other taxa such as bumblebees. In this experiment, we chronically exposed whole mature bumblebee (Bombus terrestris) colonies to field-realistic levels of the neonicotinoid thiamethoxam (2.4ppb & 10ppb) over four weeks, and compared colony growth under laboratory conditions. We found no impact of insecticide exposure on colony weight gain, or the number or mass of sexuals produced, although colonies exposed to 2.4ppb produced larger males. As previous studies have reported pesticide effects on bumblebee colony growth, this may suggest that impacts on bumblebee colonies are more pronounced for colonies at an earlier stage in the reproductive cycle. Alternatively, it may also indicate that thiamethoxam differs in toxicity compared to previously tested neonicotinoids in terms of reproductive effects. In either case, assessing bumblebee colony development under field conditions is likely more informative for real world scenarios than tests conducted in laboratory conditions. Sun, 20 Aug 2017 00:00:00 GMT http://hdl.handle.net/10379/6846 2017-08-20T00:00:00Z http://hdl.handle.net/10379/6827 Bioreactor scalability: laboratory-scale bioreactor design influences performance, ecology, and community physiology in expanded granular sludge bed bioreactors Connelly, Stephanie; Shin, Seung Gu; Dillon, Robert J.; Ijaz, Umer Zeeshan; Quince, Christopher; Sloan, William; Collins, Gavin Studies investigating the feasibility of new, or improved, biotechnologies, such as wastewater treatment digesters, inevitably start with laboratory-scale trials. However, it is rarely determined whether laboratory-scale results reflect full-scale performance or microbial ecology. The Expanded Granular Sludge Bed (EGSB) bioreactor, which is a high-rate anaerobic digester configuration, was used as a model to address that knowledge gap in this study. Two laboratory-scale idealizations of the EGSB-a one-dimensional and a three-dimensional scale-down of a full-scale design-were built and operated in triplicate under near-identical conditions to a full-scale EGSB. The laboratory-scale bioreactors were seeded using biomass obtained from the full-scale bioreactor, and, spent water from the distillation of whisky from maize was applied as substrate at both scales. Over 70 days, bioreactor performance, microbial ecology, and microbial community physiology were monitored at various depths in the sludge-beds using 16S rRNA gene sequencing (V4 region), specific methanogenic activity (SMA) assays, and a range of physical and chemicalmonitoringmethods. SMA assays indicated dominance of the hydrogenotrophic pathway at full-scale whilst a more balanced activity profile developed during the laboratory-scale trials. At each scale, Methanobacterium was the dominant methanogenic genus present. Bioreactor performance overall was better at laboratory-scale than full-scale. We observed that bioreactor design at laboratory-scale significantly influenced spatial distribution of microbial community physiology and taxonomy in the bioreactor sludge-bed, with 1-D bioreactor types promoting stratification of each. In the 1-D laboratory bioreactors, increased abundance of Firmicutes was associated with both granule position in the sludge bed and increased activity against acetate and ethanol as substrates. We further observed that stratification in the sludge-bed in 1-D laboratory-scale bioreactors was associated with increased richness in the underlying microbial community at species (OTU) level and improved overall performance. Sun, 01 Jan 2017 00:00:00 GMT http://hdl.handle.net/10379/6827 2017-01-01T00:00:00Z http://hdl.handle.net/10379/6822 Methods and techniques employed to monitor and manage carbon capture and sequestration (CCS) induced seismicity McNamara, David D. This report discusses the topic of induced seismicity resulting from the operations of subsurface CO2 injection at Carbon Capture and Storage (CCS) sites. The potential for induced seismicity to occur in CCS projects is an important factor when considering the capability of a project site s storage reservoir to retain injected CO2 for long periods of time. It is also important when assessing and addressing public concern over earthquake activity. This report discusses the measures carried out at global CCS sites to identify and monitor induced seismicity. This information is then distilled into a list of issues to be considered as part of the review process prior to establishing a CCS site in New Zealand. Fri, 01 Jan 2016 00:00:00 GMT http://hdl.handle.net/10379/6822 2016-01-01T00:00:00Z http://hdl.handle.net/10379/6820 Determination of survival of wildtype and mutant Escherichia coli in soil Somorin, Yinka; O'Byrne, Conor E. coli resides in the gastrointestinal tract of humans and other warm-blooded animals but recent studies have shown that E. coli can persist and grow in various external environments including soil. The general stress response regulator, RpoS, helps E. coli overcome various stresses, however its role in soil survival was unknown. This soil survival assay protocol was developed and used to determine the role of the general stress response regulator, RpoS, in the survival of E. coli in soil. Using this soil survival assay, we demonstrated that RpoS was important for the survival of E. coli in soil. This protocol describes the development of the soil survival assay especially the recovery of E. coli inoculated into soil and can be adapted to allow further investigations into the survival of other bacteria in soil. Thu, 20 Jul 2017 00:00:00 GMT http://hdl.handle.net/10379/6820 2017-07-20T00:00:00Z