Methane, CFCs, and Other Greenhouse Gases

Our planet is continuously bathed in solar radiation. Although we who are confined to a fixed location on the globe experience day and night, the earth does not. It is always day in the sense that the sun is shining on half of the globe. Much of the incoming solar radiation, about 30%, is scattered back to space by clouds, atmospheric gases and particles, and objects on the earth. The remaining 70% is, therefore, absorbed mostly at the earth's surface. This absorbed radiation gives up its energy to whatever absorbed it, thereby causing its temperature to increase. Because solar radiation is absorbed continuously by the earth, it might be supposed that its temperature should continue to increase. It does not, of course, because the earth also emits radiation, the spectral distribution of which is quite different from that of the incoming solar radiation. The higher the earth's temperature, the more infrared radiation it emits. At a sufficiently high temperature, the total rate of emission of infrared radiation equals the rate of absorption of solar radiation. Radiative equilibrium has been achieved, although it is a dynamic equilibrium: absorption and emission go on continuously at equal rates. The temperature at which this occurs is called the radiative equilibrium temperature of the earth. This is an average temperature, not the temperature at any one location or at any one time. It is merely the temperature that the earth, as a blackbody, must have in order to emit as much radiant energy as the earth absorbs solar energy

Stratospheric feedback from continued increases in tropospheric methane

Tropospheric concentrations of methane have increased steadily over the past ten years at an average rate of 16.5 ppbv per year, to a value in January 1988 of 1.69 ppmv. Measurements of CH sub 4 concentrations in air bubbles trapped in ice cores have shown concentrations of about 0.7 ppmv 200 years ago, with little further change for thousands of years before that. Interpolation earlier into this century suggests a concentration of about 1.1 to 1.2 ppmv in the 1940's. The only important pathway believed to be important for transfer of air from the troposphere to the stratosphere in through the tropical tropopause which is cold enough to reduce the mixing ratio of H sub 2 O in that air to about 3 ppmv. The only other major pathway for the delivery of H to the stratosphere is through the simultaneous injection of gaseous CH sub 4 in the same rising air. The formation of clouds in the stratosphere is dependent upon very low temperatures, and generally upon the amount of water vapor available. The possibility of a positive feedback exists, especially in well-oxidized methane air, that clouds are easier to form than earlier. This could mean enhancement of PSCs in both Antarctic and Arctic locations. Additional H sub 2 O in the stratosphere can also add to some of the greenhouse calculations

Methyl chloride and the U.S. cigarette.

Various brands and types of cigarettes were purchased at retail locations in southern California. Volatile gas samples were analyzed using multicolumn/multidetector gas chromatography. Results showed methyl chloride (CH(3)Cl) levels as much as four orders of magnitude higher than typical urban levels, about 30-500 ppmv (1.5-5.3 mg/cigarette), compared with about 500 pptv in urban air. The concentration of CH(3)Cl correlated well with the levels of both CO (r (2) = 0.63) and CO(2) (r (2) = 0.77), showing the link between CH(3)Cl and combustion. In some brands, CH(3)Cl levels were well above the U.S. Environmental Protection Agency's maximum exposure limit of 200 ppmv. Light branded cigarettes tended to have higher CH(3)Cl levels than the heavier and filtered brands, possibly showing the dependence of cigarette packing on CH(3)Cl production. In addition, CH(3)Cl emitted from cigarette smoke may prove to be an important anthropogenic source of CH(3)Cl in the United States, at about 5%

Bacteria in the airways of patients with cystic fibrosis are genetically capable of producing VOCs in breath.

Breath contains hundreds of volatile organic compounds (VOCs), the composition of which is altered in a wide variety of diseases. Bacteria are implicated in the formation of VOCs, but the biochemical mechanisms that lead to the formation of breath VOCs remain largely hypothetical. We hypothesized that bacterial DNA fragments in sputum of CF patients could be sequenced to identify whether the bacteria present were capable of producing VOCs found in the breath of these patients. Breath from seven patients with cystic fibrosis was sampled and analyzed by gas-chromatography and mass-spectrometry. Sputum samples were also collected and microbial DNA was isolated. Metagenomic sequencing was performed and the DNA fragments were compared to a reference database with genes that are linked to the metabolism of acetaldehyde, ethanol and methanol in the KEGG database. Bacteria in the genera Escherichia, Lactococcus, Pseudomonas, Rothia and Streptococcus were found to have the genetic potential to produce acetaldehyde and ethanol. Only DNA sequences from Lactococcus were implicated in the formation of acetaldehyde from acetate through aldehyde dehydrogenase family 9 member A1 (K00149). Escherichia was found to be genetically capable of producing ethanol in all patients, whilst there was considerable heterogeneity between patients for the other genera. The ethanol concentration in breath positively correlated with the amount of Escherichia found in sputum (Spearman rho  =  0.85,  P  =  0.015). Rothia showed the most versatile genetic potential for producing methanol. To conclude, bacterial DNA fragments in sputum of CF patients can be linked to enzymes implicated in the production of ethanol, acetaldehyde and methanol, which are VOCs that are predictive of respiratory tract colonization and/or infection. This supports that the lung microbiome can produce VOCs directly

Are We Home?

I’ve never been comfortable, and I don’t expect to be. There’s a good possibility that I don’t want to be. During my time of growing and trying to consider myself an artist, comfort has never been present. When I’m comfortable I\u27m stable, and when I’m stable I\u27m stationary. I don’t want to be stationary. Being comfortable in a place often means remaining there. I’m scared of not moving and I’m scared of staying in a place that I know. I don’t want to be within walls and structures that don’t provide me with comfort, and yet I’m uncomfortable being comfortable. This way of thinking has haunted my existence and my work since before I could understand it. I’ve come to embrace it. Through embracing these anxieties, I began taking photographs of things that I liked and things that I found interesting in hopes that I’d find comfort. I soon started to realize that the things I thought I liked were just things that made me uncomfortable. I then began searching for ways to trick myself into comfort by capturing it from others. What I can’t allow myself to have, I try to steal. In the process of stealing these moments, items, thoughts, emotions, and anything in between, I started to become more aware of where I was stealing them from. Bedrooms, churches, living rooms, bathrooms, apartments, etc. These were all physically built spaces, but the spaces had nothing to do with what I was looking at. I wasn’t looking at the shape and height of the walls in someone’s bedroom, I was looking at the notes from loved ones that they keep above their desk. I wasn’t trying to estimate the measurements of beams behind the drywall, I was wondering which piece of furniture the inhabitants chose to cry on when life isn’t treating them properly. Maybe if I trap these things in my photography then I’ll be able to understand them. I’ve finally found that comfort in itself is something that can’t be understood, but it can be portrayed. Comfort is something that doesn’t exist from nothing, but is rather created by our own memories and experience. Our comfort and places are determined by the people and things we allow near us. Even if someone is not present with us, the space we’re in can remind us that they were once there, and may be once more. In the same way, a place can bitterly remind us of what and who we won\u27t be able to experience again. Structures can’t provide us with comfort, but what’s within them can. These things that I’ve stolen may still exist for others, but are inherently fleeting. I can rest knowing that these photographs provide some sense of permanence to them. These moments, good or bad, will remain stationary while I don’t have to. There is no designated place for comfort or lack thereof, it moves and shifts along with the things that create and ruin it. Wherever these things are found, I am home

The effects of a changing marine environment on the bioeroding sponge Cliona orientalis

Bioeroding sponges are a unique group of coral reef sponges. They transform dissolved nutrients into particulate nutrients via active filter feeding whilst also eroding the coral reef framework that they inhabit. Despite their ecological importance, we know little about their distribution or abundance, especially along the inshore Great Barrier Reef (GBR). In addition, bioeroding sponges are often considered to be thermally tolerant, even though their thermal thresholds are unknown. Bioeroding sponges also occur in high abundance in polluted or eutrophic habitats, but it is unclear whether these conditions directly benefit sponges through accelerated growth or improved condition or benefit bioeroding sponges indirectly via negative effects on corals. To address these knowledge gaps, this thesis investigated whether bioeroding sponges and their photosynthetic symbionts can tolerate changing environmental conditions on coral reefs. Research focused on Cliona orientalis as it is a conspicuous bioeroding sponge on the GBR. Field surveys were used to measure the abundance of C. orientalis on the inshore GBR and laboratory experiments were performed to investigate the response of C. orientalis to ocean warming and nutrient enrichment. Decreasing coral cover on the GBR may provide opportunities for rapid growth and expansion of other taxa. The bioeroding sponges Cliona spp. may increase in abundance after coral bleaching, damage, and mortality as they withstand elevated temperatures without bleaching. In Chapter 2, I analysed benthic surveys of the inshore GBR (2005–2014) which revealed that the percent cover of C. orientalis has not increased in the past decade, as would be expected if the sponge benefited from coral bleaching or mortality. I found that the proportion of fine particles in benthic sediments was negatively associated with the presence-absence and the percent cover of this sponge, indicating that C. orientalis requires wave-exposed habitats where fine sediments are absent. The fastest increases in C. orientalis cover coincided with the lowest macroalgal cover and chlorophyll a concentration, highlighting the importance of macroalgal competition and local environmental conditions for this sponge. Given the observed distribution and habitat preferences of C. orientalis, bioeroding sponges likely represent site-specific rather than regional threats to corals and reef accretion. Coral reefs face many stressors associated with global climate change, including increasing sea surface temperature and ocean acidification. In Chapters 3 and 4, I exposed C. orientalis to temperature increments increasing from 23 to 32 °C to define the thermal tolerance threshold of the sponge and its associated microbiome. At 32 °C, or 3 °C above the maximum monthly mean (MMM) temperature, sponges bleached and the photosynthetic capacity of Symbiodinium was compromised, consistent with sympatric corals. Cliona orientalis demonstrated little capacity to recover from thermal stress, remaining bleached with reduced Symbiodinium density and energy reserves after one month at reduced temperature. While C. orientalis can withstand current temperature extremes (<3 °C above MMM) under laboratory and natural conditions, this species would not survive ocean temperatures projected for 2100 without acclimatisation or adaptation (≥3 °C above MMM). In Chapter 4, I demonstrated that bleaching of C. orientalis is preceded by a change in its microbial community, which is not restored after the thermal stress is removed. In Chapter 5, I investigated the effects of dissolved inorganic nutrients and light intensity on the growth and condition of five common Great Barrier Reef sponges, including C. orientalis, to test whether C. orientalis responds differently than other sponge species. Dissolved nutrients up to 7 μM total DIN did not significantly affect the growth, condition, or chlorophyll content of any sponge species after 10 weeks of exposure. Light (80 vs 160 μmol quanta m⁻²-2 s⁻¹) did not affect four of the five sponge species, but higher irradiance resulted in higher organic content and chlorophyll levels in C. orientalis. Hence, as ocean temperatures increase above local thermal thresholds, C. orientalis will have a negligible impact on reef erosion, and nutrient enrichment is unlikely to alter these effects

Furniture and the Atlantic Canada Condition

This paper looks at the place of furniture (as well as its indigenous fabrication) in the domestic environment, culture, and economy of eighteenth-and early nineteenth-century Atlantic Canada. Looking at the particular restrictions economy and climate set on producer and user alike, the paper examines the effect of these factors on the region's furniture. Résumé Cette communication étudie le rôle du mobilier, ainsi que les conditions de fabrication, dans la vie domestique, la culture et l'économie du XVIIIe siècle et du début du XlXe, dans la région de l'Atlantique. L'auteur étudie les restrictions particulières que l'économie et le climat imposaient au fabricant comme à l'usager, et examine l'effet de ces facteurs sur le mobilier de la région

Air quality in the Industrial Heartland of Alberta, Canada and potential impacts on human health.

The "Industrial Heartland" of Alberta is Canada's largest hydrocarbon processing center, with more than 40 major chemical, petrochemical, and oil and gas facilities. Emissions from these industries affect local air quality and human health. This paper characterizes ambient levels of 77 volatile organic compounds (VOCs) in the region using high-precision measurements collected in summer 2010. Remarkably strong enhancements of 43 VOCs were detected, and concentrations in the industrial plumes were often similar to or even higher than levels measured in some of the world's largest cities and industrial regions. For example maximum levels of propene and i-pentane exceeded 100 ppbv, and 1,3-butadiene, a known carcinogen, reached 27 ppbv. Major VOC sources included propene fractionation, diluent separation and bitumen processing. Emissions of the measured VOCs increased the hydroxyl radical reactivity (kOH), a measure of the potential to form downwind ozone, from 3.4 s-1 in background air to 62 s-1 in the most concentrated plumes. The plume value was comparable to polluted megacity values, and acetaldehyde, propene and 1,3-butadiene contributed over half of the plume kOH. Based on a 13-year record (1994-2006) at the county level, the incidence of male hematopoietic cancers (leukemia and non-Hodgkin lymphoma) was higher in communities closest to the Industrial Heartland compared to neighboring counties. While a causal association between these cancers and exposure to industrial emissions cannot be confirmed, this pattern and the elevated VOC levels warrant actions to reduce emissions of known carcinogens, including benzene and 1,3-butadiene