Population Dynamics and Community Composition of Ammonia Oxidizers in Salt Marshes after the Deepwater Horizon Oil Spill

The recent oil spill in the Gulf of Mexico had significant effects on microbial communities in the Gulf, but impacts on nitrifying communities in adjacent salt marshes have not been investigated. We studied persistent effects of oil on ammonia-oxidizing archaeal (AOA) and bacterial (AOB) communities and their relationship to nitrification rates and soil properties in Louisiana marshes impacted by the Deepwater Horizon oil spill. Soils were collected at oiled and unoiled sites from Louisiana coastal marshes in July 2012, 2 years after the spill, and analyzed for community differences based on ammonia monooxygenase genes (amoA). Terminal Restriction Fragment Polymorphism and DNA sequence analyses revealed significantly different AOA and AOB communities between the three regions, but few differences were found between oiled and unoiled sites. Community composition of nitrifiers was best explained by differences in soil moisture and nitrogen content. Despite the lack of significant oil effects on overall community composition, we identified differences in correlations of individual populations with potential nitrification rates between oiled and unoiled sites that help explain previously published correlation patterns. Our results suggest that exposure to oil, even 2 years post-spill, led to subtle changes in population dynamics. How, or if, these changes may impact ecosystem function in the marshes, however, remains uncertain

Effects of Deepwater Horizon oil on feather structure and thermoregulation in gulls: Does rehabilitation work?

Impacts of large-scale oil spills on avian species are far-reaching.While media attention often focuses on lethal impacts, sub-lethal effects and the impacts of rehabilitation receive less attention. The objective of our study was to characterize effects of moderate external oiling and subsequent rehabilitation on feather structure and thermoregulation in gulls. We captured 30 wild ring-billed gulls (Larus delawarensis) and randomly assigned each individual to an experimental group: 1) controls, 2) rehabilitated birds (externally oiled, rehabilitated by washing), or 3) oiled birds (externally oiled, not rehabilitated). We externally oiled birds with weathered MC252 Deepwater Horizon oil (water for controls) and collected feathers and thermography imagery (FLIR) approximately weekly for four weeks to investigate feather structure (quantified using a barbule clumping index) and thermoregulatory ability (characterized by internal body temperature and external surface temperature). Post-oiling feather clumping was significantly higher in oiled and rehabilitated birds compared to controls, but steadily declined over time in both groups. However, feather microstructure in rehabilitated birds was indistinguishable from controls within three weeks of washing whereas the feathers of oiled birds were still significantly clumped a month post oiling. Internal body temperatures didn\u27t differ in any of the groups, suggesting birds maintain thermoregulatory homeostasis in spite of moderate external oiling. External temperatures for rehabilitated birds didn\u27t differ from controls within a week of rehabilitation. Overall, rehabilitation procedures were effective and washed birds were in better condition compared to non-rehabilitated, oiled birds. This study provides evidence that the benefits of rehabilitation for moderately oiled birds likely outweigh the costs with regard to feather structure and thermoregulation.While feather preening and time were insufficient to reestablish baseline fine scale feather structure in moderately oiled birds, the significant clumping reduction over time may indicate that rehabilitation of lightly oiled birds may not be necessary and deserves further study

Assemblage Comparisons of Living Benthic Foraminifera at Bathyal Sites Oiled and Un-Oiled by the Deepwater Horizon Blowout in the Northeastern Gulf of Mexico

Live benthic foraminiferal assemblages were studied at contaminated and uncontaminated bathyal sites around the wellhead of the Deepwater Horizon oil spill. Samples collected in October of 2010 and 2011 and summer of 2012 were divided into uncontaminated (GIP 12, 21, K, and 25 and Obs0), moderately oiled (GIP 16 and 17) and heavily oiled groups (GIP 15), in which the TPAH concentrations ranged from 29 to 7,553 ng/g in 2010. Metric multidimensional scaling (MDS) and cluster analyses were conducted to compare all surface samples. Additionally, the heavily oiled site (GIP 15) and an uncontaminated site (GIP 25) were studied downcore to assess the impact on the foraminiferal depth of habitation (DOH). A total of 284 species from 6 suborders have been identified in the ≥ 45-μm size fraction. Three pseudo-replicates at Obs0 had more similarity in species distribution and diversity than any other site. The MDS and cluster analyses show that the surface assemblages are within a single biofacies except for two sites (GIP 21 and K). The assemblages from the heavily oiled and un-oiled cores were distinctly different. In 2010, the standing stock was nearly two times greater at the heavily oiled site, but the DOH was half the depth of the un-oiled site. In 2011, the standing stock of the two sites was similar, but the DOH remained shallower at the oiled site. The trends in density, DOH, standing stock, diversity, and abundance of an opportunistic species (Bulimina aculeata) at the heavily oiled site appear consistent with hypertrophy

ENERGY VALUE OF DE-OILED DISTILLERS GRAINS PLUS SOLUBLES IN BEEF CATTLE DIETS

Ethanol plants are centrifuging off oil from the thin stillage stream as it has added market value currently. The impact of oil removal on cattle performance has been minimally researched. Thus four trials, one growing, one digestion, and two feedlot, were designed to determine the energy and feeding value of de-oiled distillers grains in beef cattle diets. In growing cattle diets, diet concentration of modified distillers grains plus solubles (MDGS) impacted cattle performance more than oil content. Ending BW, ADG, and G:F did not differ between cattle fed de-oiled or full fat MDGS, however cattle fed de-oiled MDGS had lower DMI than those fed full fat MDGS. No significant differences in fiber digestibility were observed between de-oiled and full fat MDGS treatments. The energy value of de-oiled MDGS in growing cattle diets was calculated to be 124% the value of corn. In finishing steer diets, increasing diet concentrations of de-oiled MDGS increased G:F. However, decreasing MDGS fat content from 12.0% to 7.2% decreased steer performance by 3.4%. No significant interactions were observed when increasing concentrations of de-oiled wet distillers grains plus solubles (WDGS) were fed with steam flaked (SFC) or dry rolled corn (DRC). Comparison of steer performance when de-oiled and full fat WDGS are fed in SFC and DRC diets resulted in no significant differences also. In growing and finishing diets small differences in cattle performance have been observed. Energy values for distillers grain in growing diets are still high with no improvements in fiber digestibility being observed. In finishing diets where distillers grains were fed at 30-35%, de-oiled distillers grains have 89% the feeding value of full fat distillers grain. Key Words: corn processing, digestion, de-oiled, finishing, growing Advisors: Galen E. Erickson and Matthew K. Luebb

Mechanism of impact and potential recovery of pigeon guillemots (Cepphus columba) after the Exxon Valdez oil spill

Thesis (M.S.) University of Alaska Fairbanks, 2000The abundance of pigeon guillemots in oiled areas of Prince William Sound, Alaska, failed to increase after the 1989 Exxon Valdez oil spill. Population growth may be constrained by the physiological effects of oil exposure, food availability, and nest predation." The author "conducted a comparative study among unoiled, oiled, and pre-spill data sets, to provide insight on factors limiting population recovery in oiled areas. Blood samples from chicks in oiled and unoiled areas provided little evidence of physiological effects of exposure to oil. Pigeon guillemot diet, productivity, growth rates, and fledging weights in unoiled areas of southwestern Prince William Sound from 1994 to 1998 indicate oiled areas had a lower proportion of high-lipid fish in the chick diet and lower fledging weights, compared to unoiled and pre-spill studies. These results suggest that the lack of recovery in oiled areas is associated with a prey base that results in lower fledging weights, which may reduce juvenile survival

Investigative Study on the Use of De-Oiled Palm Kernel Cake for Biogas Production

Availability of Palm Kernel Cake (PKC) has increased due to the increase in the number of cottage oil palm processing industries in developing countries. A quest for clean energy from bio-waste is also on the increase. This study aims at investigating the biogas generating capacity of de-oiled PKC and its corresponding methane content. De-oiled PKC and a mixture of de-oiled PKC and fresh sugar cane chips were used as the two bio-feed samples in a laboratory anaerobic digestion set up. A theoretical approach was also used to determine the expected methane content in the biogas. Laboratory results for de-oiled PKC gave the volume by weight of bio-feed for biogas and methane to be 12.7 ml/g and 4.2 ml/g respectively and that of the combination of de-oiled PKC and fresh sugar cane chips to be 3.15 ml/g and 1.25 ml/g respectively. The measured methane composition for de-oiled PKC and that of the combination of de-oiled PKC and fresh sugar cane chips to be 33% and 40% respectively while the theoretical estimates were 33.5% and 41.1% respectively. The study shows that de-oiled palm kernel cake has biogas/methane generation potential whose quality can be improved by the addition of other biogas producing wastes.KEYWORDS: Biogas, Agro-Industrial Waste, Palm Kernel Cake, Anaerobic Digestion, Wastewater

Impact of Dietary Fat Source on Beef Tenderness

Steers were finished on either a corn control, 40% full-fat modified distillers grains plus solubles, 40% de-oiled modified distillers grains plus solubles, or 38% de-oiled modified distillers grains plus solubles plus 2% corn oil diet to evaluate the effects of dietary fat source on the mechanism of beef tenderization . Feeding modified distillers grains plus solubles increased polyunsaturated fatty acid content in the sarcoplasmic reticulum membrane and increased free Ca2+ concentration early postmortem. Steaks from cattle fed de-oiled modified distillers grains and de-oiled modified distillers grains plus corn oil were more tender at 2 d of aging when compared to corn control diet. These data indicate that feeding modified distillers grains plus solubles to cattle has the potential to increase beef tenderness early postmortem in comparison to corn diets

Impact of Feeding Distillers Grains With or Without Oil Removal As Well As Supplemental Corn Oil on Nutrient Digestibility by Finishing Cattle

A digestion trial was conducted to determine the effects of the removal of corn oil from modified distillers grains plus solubles (MDGS) and the impact of supplemental corn oil on finishing cattle nutrient digestion. Four treatments were evaluated: a corn control diet (CON), 40% de-oiled MDGS (DO MDGS), or 38% de-oiled MDGS plus 2% corn oil (MDGS + Oil) formulated to equal the fat content of FF MDGS, or 40% full fat MDGS (FF MDGS). Treatment differences were observed for digestibility of dry matter, organic matter, and fiber, but not for fat. When oil was added to de-oiled MDGS, digestibility was decreased for dry matter, organic matter, and fiber when compared to de-oiled or full fat MDGS. Digestibility values from feeding DGS relative to corn control diets do not follow the same trend, digestible energy increases with DGS feeding, but OM digestibility decreases with DGS feeding

Impact of Corn Oil Removal from Modified Distillers Grains Plus Solubles and Supplemental Corn Oil on Finishing Cattle Performance

A finishing study was conducted to evaluate removal of corn oil from modified distillers grains plus solubles (MDGS) and replacement of supplemental corn oil on finishing cattle performance. Four treatments were evaluated: a corn control diet, 40% de-oiled MDGS, 38% de-oiled MDGS plus 2% corn oil to equal the fat content of full fat MDGS, or 40% full fat MDGS. There was a significant improvement in ADG and F:G for cattle fed de-oiled MDGS plus oil compared to other treatments. Cattle fed full fat MDGS had numerically lower ADG and numerically poorer F:G (3.7%) compared with cattle fed MDGS plus oil. Cattle fed de-oiled MDGS had greater intake and numerically higher ADG than full fat MDGS, however F:G was similar (1.2%). Even with the improvement in feed conversion, the benefit is too small to make adding corn oil to the diet economical at current prices

Milk Yield Response of Bypass Protein on Smallholder Dairy Animals

Protein need for small holder dairy animals is very limited. Considering this problem one on-station and one on-farm trails were conducted in 2013 and 2014 in Nepal respectively. In on-station trial (2013) 15 milking buffaloes were randomly assigned to 5 dietary treatments (0, 0.5, 1, 1.5 and 2 kg de-oiled soybean meals/day/buffalo) and in on-farm trial (2014), 20 milking buffaloes were assigned to 0.5 kg de-oiled soybean meal/day/buffalo for two months dry period. From on-station trial, significantly higher (42 %) milk production was observed from 0.5 kg and 1 kg de-oiled soybean meal/day/buffalo feeding groups. From the on-farm trials in village dairy buffaloes 20 percent milk production increment was observed compared with the normal farmer's feeding practices (de-oiled soybean meals unfed condition). It was concluded that, in addition to normal diet, 0.5 to 1 kg de-oiled soybean meal (depending up on the body weight of animal and feeding situation) per day feeding as bypass protein sources could be beneficial during dry period where green fodder is scarce to maintain milk production from dairy animals