UV photolysis of quinoline in interstellar ice analogs

Abstract— The polycyclic aromatic nitrogen heterocycle (PANH) quinoline (C₉H₇N) was frozen at 20 K in interstellar ice analogs containing either pure water or water mixed with methanol or methane and exposed to ultraviolet (UV) radiation. Upon warming, the photolysis products were analyzed by high‐performance liquid chromatography and nanoscale liquid chromatography‐electrospray ionization mass spectrometry. A suite of hydroxyquinolines, which were formed by the addition of oxygen atoms to quinoline, was observed as the primary product in all the ices. Quinoline N oxide was not formed, but five hydroxyquinoline isomers were produced with no clear dominance of one isomer. Reduction products, formed by hydrogen atom addition, were also created. Ices created at 20 K with H₂O: quinoline ratios of 10:1 to 100:1 showed similar product distributions to those at 122 K, with no apparent temperature or concentration dependence. Increasing the UV dose led to a decrease in overall yield, indicating that quinoline and its products may be photo‐destroyed. Methylquinolines were formed upon photolysis of the methanol‐ and methane‐containing ices. In addition, possible methoxyquinolines or quinoline methylene alcohols were formed in the methanol‐containing ice, while methylhydroxyquinolines were created in the methane‐containing ice. This work indicates that oxidation of PANHs could occur in icy extraterrestrial environments and suggests that a search for such compounds in carbonaceous meteorites could illuminate the possible link between interstellar ice chemistry and meteoritic organics. Given the importance of oxidized and alkylated PANHs to biochemistry, the formation and delivery of such molecules to the early Earth may have played a role in the origin and evolution of life.     

Mid‐infrared study of stones from the Sutter's Mill meteorite

The Sutter's Mill meteorite fell in northern California on April 22, 2012. Several fragments of the meteorite were recovered, some of them shortly after the fall, others several days later after a heavy rainstorm. In this work, we analyzed several samples of four fragments―SM2, SM12, SM20, and SM30―from the Sutter's Mill meteorite with two infrared (IR) microscopes operating in the 4000–650 cm^?1 (2.5–15.4 μm) range. Spectra show absorption features associated with minerals such as olivines, phyllosilicates, carbonates, and possibly pyroxenes, as well as organics. Spectra of specific minerals vary from one particle to another within a given stone, and even within a single particle, indicating a nonuniform mineral composition. Infrared features associated with aliphatic CH₂ and CH₃ groups associated with organics are also seen in several spectra. However, the presence of organics in the samples studied is not clear because these features overlap with carbonate overtone bands. Finally, other samples collected within days after the rainstorm show evidence for bacterial terrestrial contamination, which indicates how quickly meteorites can be contaminated on such small scales.     

A Test of Bycatch Reduction Devices on Commercial Crab Pots in a Tidal Marsh Creek in Virginia

The effectiveness of bycatch reduction devices (BRDs) on commercial pots designed to capture blue crabs Callinectes sapidus was tested in the York River on Felgates Creek (37.2667 N, −76.5850 W) over the period 4 June through 31 July 2009. For each of 10 pairs of pots, one had BRDs affixed to all four entrance gapes and the other had none. Pots were baited approximately once each week but were sampled for blue crabs and bycatch 6 of 7 days each week for the duration of the study. More than one fourth of 1,643 total crabs were caught on the first day after baiting, and for these 7 days, no statistical difference was detected between either the number or size of legal-size crabs caught in BRD versus non-BRD pots. Of 51 Malaclemys terrapin and 44 fish caught as bycatch throughout the study, all but three fish were captured in non-BRD pots. BRDs exclude bycatch and may reduce incidental mortality of crabs in pots that are not tended regularly.     

Environmental and Physical Controls on the Formation and Transport of Blooms of the Dinoflagellate <Emphasis Type="Italic">Cochlodinium polykrikoides</Emphasis> Margalef in the Lower Chesapeake Bay and Its Tributaries

Massive blooms of the harmful alga Cochlodinium polykrikoides Margalef occurred in the lower Chesapeake Bay and its tributaries during the summers of 2007 and 2008. The Lafayette and Elizabeth Rivers appeared to act as initiation grounds for these blooms during both years. However, in 2008 there were also localized sites of initiation and growth of populations within the mesohaline portion of the James River. Bloom initiation appeared to be correlated with intense, highly localized rainfall events during neap tides. Subsequent spring tides increased tidal flushing and transport of C. polykrikoides from the Lafayette and Elizabeth Rivers into the lower James River where it was transported upriver by local estuarine circulation. Blooms dissipated in response to increased wind-driven mixing associated with frontal systems moving through the region. A combination of physical factors including, seasonal rainfall patterns, increased stratification, nutrient loading, spring-neap tidal modulation, and complex estuarine mixing and circulation allowed C. polykrikoides to spread and form massive blooms over large portions of the tidal James River and the lower Chesapeake Bay.