[1] Short-lived halocarbon tracers were used to investigate marine influences on air quality in a coastal region of New England. Atmospheric measurements made at the University of New Hampshire's Observing Station at Thompson Farm (TF) in Durham, New Hampshire, indicate that relatively large amounts of halocarbons are emitted from local estuarine and coastal oceanic regions. Bromine-containing halocarbons of interest in this work include bromoform (CHBr 3 ) and dibromomethane (CH 2 Br 2 ). The mean mixing ratios of CHBr 3 and CH 2 Br 2 from 11 January to 5 March 2002 were 2.6 pptv and 1.6 pptv, and from 1 June to 31 August 2002 mean mixing ratios were 5.9 pptv and 1.4 pptv, respectively. The mean mixing ratio of CHBr 3 was not only highest during summer, but both CHBr 3 and CH 2 Br 2 exhibited large variability in their atmospheric mixing ratios during this season. We attribute the greater variability to increased production combined with faster atmospheric removal rates. Other seasonal characteristics of CHBr 3 and CH 2 Br 2 in the atmosphere, as well as the impact of local meteorology on their distributions at this coastal site, are discussed. Tetrachloroethene (C 2 Cl 4 ) and trichloroethene (C 2 HCl 3 ) were used to identify time periods influenced by urban emissions. Additionally, measurements of CHBr 3, CH 2 Br 2, C 2 Cl 4 , methyl iodide (CH 3 I), and ethyl iodide (C 2 H 5 I) were made at TF and five sites throughout the nearby Great Bay estuarine area between 18 and 19 August 2003. These measurements were used to elucidate the effect of the tidal cycle on the distributions of these gases. The mean mixing ratios of CHBr 3 , CH 2 Br 2 , CH 3 I, and C 2 H 5 I were $82%, 46%, 14%, and 17% higher, respectively, near the coast compared to inland sites, providing evidence for a marine source of short-lived halocarbons at TF. Correlation between the tidal cycle and atmospheric concentrations of marine tracers on the night of 18 August 2003 showed that the highest values for the brominated species occurred $2-3 hours after high tide. Emission fluxes of CHBr 3 , CH 2 Br 2 , CH 3 I, and C 2 H 5 I on this night were estimated to be 26 ± 57, 4.7 ± 5.4, 5.9 ± 4.6, and 0.065 ± 0.20 nmol m À2 h À1 , respectively. Finally, the anthropogenic source strength of CHBr 3 was calculated to determine its impact on atmospheric levels observed in this region. Although our results indicate that anthropogenic contributions could potentially range from 15 to 60% of the total dissolved CHBr 3 in the Great Bay, based on the observed ratio of CH 2 Br 2 /CHBr 3 and surface seawater measurements in the Gulf of Maine, it appears unlikely that anthropogenic activities are a significant source of CHBr 3 in the region.

Abstract. Seven C 1 -C 5 alkyl nitrates were measured both on the mainland and off the coast of New Hampshire using gas chromatographic techniques. Five separate data sets are presented to characterize the seasonal and diurnal trends and the major sources and loss processes of these compounds. Based on in situ measurements conducted at the University of New Hampshire (UNH) Atmospheric Ob- Comparison with wind speed and trace gas trends suggested that dry deposition contributed to the early morning MeONO 2 minimum which is a previously unaccounted for removal mechanism. The mean dry deposition rate and velocity of MeONO 2 was estimated to be −0.5 nmol m −2 hr −1 and 0.13 cm s −1 , respectively. Results from ambient air and surface seawater measurements made onboard the NOAA R/V Ronald H. Brown in the Gulf of Maine during the 2002 New England Air Quality Study and from ambient canister samples collected throughout the Great Bay estuary in August 2003 are also presented. Comparisons between the alkyl nitrate trends with anthropogenic and marine tracers suggest that a marine source of alkyl nitrates is not significant in coastal New England. Given the apparent prominence of a secondary source, comparisons beCorrespondence to: R. S. Russo (rrusso@gust.sr.unh.edu) tween observed and predicted alkyl nitrate/parent hydrocarbon ratios were made which demonstrated that background mixing ratios have a continuous and prevalent influence on the alkyl nitrate distribution.

Oceanic iron (Fe) fertilization experiments have advanced the understanding of how Fe regulates biological productivity and air-sea carbon dioxide (CO2) exchange. However, little is known about the production and consumption of halocarbons and other gases as a result of Fe addition. Besides metabolizing inorganic carbon, marine microorganisms produce and consume many other trace gases. Several of these gases, which individually impact global climate, stratospheric ozone concentration, or local photochemistry, have not been previously quantified during an Feenrichment experiment. We describe results for selected dissolved trace gases including methane (CH4), isoprene (C5H8), methyl bromide (CH 3Br), dimethyl sulfide, and oxygen (O2), which increased subsequent to Fe fertilization, and the associated decreases in concentrations of carbon monoxide (CO), methyl iodide (CH 3I), and CO 2 observed during the Southern Ocean Iron Enrichment Experiments. P revious iron (Fe) fertilization experiments have been conducted in the North (1) and equatorial Pacific (2, 3) and in the Southern Ocean (4, 5). The Southern Ocean, the largest of the high-nutrient low-chlorophyll regions, represents 6% of the global ocean and has the potential to enhance carbon sequestration by Fe fertilization (6-9), which could slow carbon dioxide (CO 2 ) accumulation in the atmosphere and potentially help alleviate global warming. Experimental MethodsThe experimental design and other results of the Southern Ocean Iron Enrichment Experiment (SOFeX) are presented in an overview paper (8). Of the two regions fertilized with Fe during SOFeX, we focus here on the region north of the Antarctic Polar Front. An area Ϸ15 ϫ 15 km at 56.2°S, 172.0°W (southeast of New Zealand in the southwest Pacific sector of the Southern Ocean) was fertilized with a solution of acidified iron sulfate (FeSO 4 ) over 48 h to a concentration of Ϸ1.2 ϫ 10 Ϫ9 mol⅐liter Ϫ1 (1.2 nM) beginning on January 12, 2002. The background Fe concentration ([Fe]) was Ϸ0.1 nM. A second (36 h) application of FeSO 4 (Ϸ1.2 nM) ended on January 17. These Fe additions were intended to simulate glacial era concentrations of iron in the Southern Ocean (8, 10). The region, or patch, was allowed time to bloom and then was surveyed over a 50-h period, between February 8 and 10, 4 weeks after the first Fe application. By this time the patch had reached a surface area that was a factor of 10 larger than during the initial Fe addition with iron concentrations in the patch of Ϸ0.3 nM (8). During this survey we approached the patch from the South working our way northeast, while crisscrossing the patch. After the shape and orientation of the patch became apparent [elongated and stretching from the southwest to the northeast (11)], more intensive sampling began along the patch. Observations of fluorescence, the partial pressure of CO 2 in seawater (pCO 2 ) (Fig. 1A), dissolved O 2 (Fig. 1B), chlorophyll, and primary productivity indicated a pronounced change in biological activity in the mixed layer (upper 40-5...

Wastewaters from oil and gas development pose largely unknown risks to environmental resources. In January 2015, 11.4ML (million liters) of wastewater (300g/L TDS) from oil production in the Williston Basin was reported to have leaked from a pipeline, spilling into Blacktail Creek, North Dakota. Geochemical and biological samples were collected in February and June 2015 to identify geochemical signatures of spilled wastewaters as well as biological responses along a 44-km river reach. February water samples had elevated chloride (1030mg/L) and bromide (7.8mg/L) downstream from the spill, compared to upstream levels (11mg/L and <0.4mg/L, respectively). Lithium (0.25mg/L), boron (1.75mg/L) and strontium (7.1mg/L) were present downstream at 5-10 times upstream concentrations. Light hydrocarbon measurements indicated a persistent thermogenic source of methane in the stream. Semi-volatile hydrocarbons indicative of oil were not detected in filtered samples but low levels, including tetramethylbenzenes and di-methylnaphthalenes, were detected in unfiltered water samples downstream from the spill. Labile sediment-bound barium and strontium concentrations (June 2015) were higher downstream from the Spill Site. Radium activities in sediment downstream from the Spill Site were up to 15 times the upstream activities and, combined with Sr isotope ratios, suggest contributions from the pipeline fluid and support the conclusion that elevated concentrations in Blacktail Creek water are from the leaking pipeline. Results from June 2015 demonstrate the persistence of wastewater effects in Blacktail Creek several months after remediation efforts started. Aquatic health effects were observed in June 2015; fish bioassays showed only 2.5% survival at 7.1km downstream from the spill compared to 89% at the upstream reference site. Additional potential biological impacts were indicated by estrogenic inhibition in downstream waters. Our findings demonstrate that environmental signatures from wastewater spills are persistent and create the potential for long-term environmental health effects.

[1] Atmospheric measurements of bromoform (CHBr 3 ) and dibromomethane (CH 2 Br 2 ) were conducted at two sites, Thompson Farm (TF) in Durham, New Hampshire (summer 2002-2004, and Appledore Island (AI), Maine (summer 2004). Elevated mixing ratios of CHBr 3 were frequently observed at both sites, with maxima of 37.9 parts per trillion by volume (pptv) and 47.4 pptv for TF and AI, respectively. Average mixing ratios of CHBr 3 and CH 2 Br 2 at TF for all three summers ranged from 5.3-6.3 and 1.3-2.3 pptv, respectively. The average mixing ratios of both gases were higher at AI during 2004, consistent with AI's proximity to sources of these bromocarbons. Strong negative vertical gradients in the atmosphere corroborated local sources of these gases at the surface. At AI, CHBr 3 and CH 2 Br 2 mixing ratios increased with wind speed via sea-to-air transfer from supersaturated coastal waters. Large enhancements of CHBr 3 and CH 2 Br 2 were observed at both sites from 10 to 14 August 2004, coinciding with the passage of Tropical Storm Bonnie. During this period, fluxes of CHBr 3 and CH 2 Br 2 were 52.4 ± 21.0 and 9.1 ± 3.1 nmol m À2 h À1 , respectively. The average fluxes of CHBr 3 and CH 2 Br 2 during nonevent periods were 18.9 ± 12.3 and 2.6 ± 1.9 nmol m À2 h À1 , respectively. Additionally, CHBr 3 and CH 2 Br 2 were used as marine tracers in case studies to (1) evaluate the impact of tropical storms on emissions and distributions of marine-derived gases in the coastal region and (2) characterize the transport of air masses during pollution episodes in the northeastern United States.

Abstract.A long-term, high time-resolution volatile organic compound (VOC) data set from a ground site that experiences urban, rural, and marine influences in the Northeastern United States is presented. A proton-transfer-reaction mass spectrometer (PTR-MS) was used to quantify 15 VOCs: a marine tracer dimethyl sulfide (DMS), a biomass burning tracer acetonitrile, biogenic compounds (monoterpenes, isoprene), oxygenated VOCs (OVOCs: methyl vinyl ketone (MVK) plus methacrolein (MACR), methanol, acetone, methyl ethyl ketone (MEK), acetaldehyde, and acetic acid), and aromatic compounds (benzene, toluene, C 8 and C 9 aromatics). Time series, overall and seasonal medians, with 10th and 90th percentiles, seasonal mean diurnal profiles, and inter-annual comparisons of mean summer and winter diurnal profiles are shown. Methanol and acetone exhibit the highest overall median mixing ratios 1.44 and 1.02 ppbv, respectively. Comparing the mean diurnal profiles of less well understood compounds (e.g., MEK) with better known compounds (e.g., isoprene, monoterpenes, and MVK + MACR) that undergo various controls on their atmospheric mixing ratios provides insight into possible sources of the lesser known compounds. The constant diurnal value of ∼0.7 for the toluene:benzene ratio in winter, may possibly indicate the influence of wood-based heating systems in this region. Methanol exhibits an initial early morning release in summer unlike any other OVOC (or isoprene) and a dramatic late afternoon mixing ratio increase in spring. Although several of the OVOCs appear to have biogenic sources, differences in features observed between isoprene, methanol, acetone, acetaldehyde, and MEK suggest they are produced or emitted in unique ways.

Abstract. Summertime atmospheric toluene enhancements at Thompson Farm in the rural northeastern United States were unexpected and resulted in a toluene/benzene seasonal pattern that was distinctly different from that of other anthropogenic volatile organic compounds. Consequently, three hydrocarbon sources were investigated for potential contributions to the enhancements during [2004][2005][2006]. These included: (1) increased warm season fuel evaporation coupled with changes in reformulated gasoline (RFG) content to meet US EPA summertime volatility standards, (2) local industrial emissions and (3) local vegetative emissions. The contribution of fuel evaporation emission to summer toluene mixing ratios was estimated to range from 16 to 30 pptv d −1 , and did not fully account for the observed enhancements (20-50 pptv) in [2004][2005][2006]. Static chamber measurements of alfalfa, a crop at Thompson Farm, and dynamic branch enclosure measurements of loblolly pine trees in North Carolina suggested vegetative emissions of 5 and 12 pptv d −1 for crops and coniferous trees, respectively. Toluene emission rates from alfalfa are potentially much larger as these plants were only sampled at the end of the growing season. Measured biogenic fluxes were on the same order of magnitude as the influence from gasoline evaporation and industrial sources (regional industrial emissions estimated at 7 pptv d −1 ) and indicated that local vegetative emissions make a significant contribution to summertime toluene enhancements. Additional studies are needed to characterize the variability and factors controlling toluene emissions from alfalfa and other vegetation types throughout the growing season.

[1] Increasing atmospheric mixing ratios of CO 2 have already lowered surface ocean pH by 0.1 units compared to preindustrial values and pH is expected to decrease an additional 0.3 units by the end of this century. Pronounced physiological changes in some phytoplankton have been observed during previous CO 2 perturbation experiments. Marine microorganisms are known to consume and produce climate-relevant organic gases. Concentrations of (CH 3 ) 2 S (DMS) and CH 2 ClI were quantified during the Third Pelagic Ecosystem CO 2 Enrichment Study. Positive feedbacks were observed between control mesocosms and those simulating future CO 2 . Dimethyl sulfide was 26% (±10%) greater than the controls in the 2x ambient CO 2 treatments, and 18% (±10%) higher in the 3xCO 2 mesocosms. For CH 2 ClI the 2xCO 2 treatments were 46% (±4%) greater than the controls and the 3xCO 2 mesocosms were 131% (±11%) higher. These processes may help contribute to the homeostasis of the planet. Citation: Wingenter, O. W., et al.(2007), Unexpected consequences of increasing CO 2 and ocean acidity on marine production of DMS and CH 2 ClI: Potential climate impacts, Geophys. Res. Lett., 34, L05710,