Large-scale distributions of tropospheric nitric, formic, and acetic acids over the western Pacific basin during wintertime

We report here measurements of the acidic gases nitric (HNO3), formic (HCOOH), and acetic (CH3COOH) over the western Pacific basin during the February-March 1994 Pacific Exploratory Mission-West (PEM-West B). These data were obtained aboard the NASA DC-8 research aircraft as it flew missions in the altitude range of 0.3–12.5 km over equatorial regions near Guam and then further westward encompassing the entire Pacific Rim arc. Aged marine air over the equatorial Pacific generally exhibited mixing ratios of acidic gases \u3c100 parts per trillion by volume (pptv). Near the Asian continent, discrete plumes encountered below 6 km altitude contained up to 8 parts per billion by volume (ppbv) HNO3 and 10 ppbv HCOOH and CH3COOH. Overall there was a general correlation between mixing ratios of acidic gases with those of CO, C2H2, and C2Cl4, indicative of emissions from combustion and industrial sources. The latitudinal distributions of HNO3 and CO showed that the largest mixing ratios were centered around 15°N, while HCOOH, CH3COOH, and C2Cl4 peaked at 25°N. The mixing ratios of HCOOH and CH3COOH were highly correlated (r2 = 0.87) below 6 km altitude, with a slope (0.89) characteristic of the nongrowing season at midlatitudes in the northern hemisphere. Above 6 km altitude, HCOOH and CH3COOH were marginally correlated (r2 = 0.50), and plumes well defined by CO, C2H2, and C2Cl4 were depleted in acidic gases, most likely due to scavenging during vertical transport of air masses through convective cloud systems over the Asian continent. In stratospheric air masses, HNO3 mixing ratios were several parts per billion by volume (ppbv), yielding relationships with O3 and N2O consistent with those previously reported for NOy

Barcoding of NH Mayflies

The presence of different macroinvertebrate species can be an important indicator of the overall health of freshwater systems. Two important things that macroinvertebrates can signal are oxygen content and extent of eutrophication. However, certain aquatic species, including mayflies (Order: Ephemeroptera), can be nearly impossible to identify to species using phenotypic features alone, and without all associated life stages under consideration. Analysis of genetic markers can be useful to accurately determine the species designation of collected specimens. Previous studies in mayflies have used the mitochondrial cytochrome c oxidase subunit 1 (CO1) gene to successfully assign species. This method is known as barcoding. For my work on two genera of flat-headed mayflies (Heptageniidae: Epeorus and Maccaffertium), 20 mayfly nymphs of each were collected at eight different water sites throughout New Hampshire. Collection sites included as far north as Woodstock, NH and as far south as Peterborough, NH. DNA was isolated from the nymphal leg tissue (rich in mitochondria), or the thorax was used when the legs were unavailable. Efforts are underway to sequence a portion of the CO1 gene from these specimens and determine species for each. This study is the first of its kind for mayflies in NH and will help with efforts to monitor the water quality across the state

Observations on the Rare-Earths: Chemical and Electrochemical Studies Ofsolutions of Rare-Earth Metal Salts in Anhydrous Dimethylformamide

104 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1958.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD

Measurements of Tropospheric Nitric Acid Over the Western United States and Northeastern Pacific Ocean

During the August-September 1986 GTE/CITE 2 aircraft mission, more than 240 measurements of nitric acid (HNO3) were made in the free troposphere as well as in the boundary layer over the northeastern Pacific Ocean and western continental United States. Marine HNO3 measurement results were strikingly similar to results from GAMETAG and other past atmospheric field experiments. The marine boundary layer HNO3 average, 62 parts per trillion by volume (pptv), was one third lower than the marine free tropospheric average, 108 pptv, suggesting that the boundary layer is a sink for tropospheric nitric acid, probably by dry deposition. Nitric acid measurements on a nighttime continental flight gave a free tropospheric average of 218 pptv, substantially greater than the daytime continental free tropospheric five-flight average of 61 pptv. However, the nighttime results may have been influenced by highly convective conditions that existed from thunderstorms in the vicinity during that night flight. Our continental boundary layer HNO3 average of 767 pptv is an order of magnitude greater than the free tropospheric average, indicating that the boundary layer is a source of free tropospheric HNO3. The distribution of continental boundary layer HNO3 data, from averages of 123 pptv over rural Nevada and Utah to 1057 pptv in the polluted San Joaquin Valley of California suggests a close tie between boundary layer HNO3 and anthropogenic activity