Isotopic compositions of organic and inorganic nitrogen reveal processing and source dynamics at septic influenced and undeveloped estuary sites.

Historically, dissolved organic nitrogen (DON) has not been characterized in the nitrogen profiles of most estuaries despite its significant contribution to total nitrogen and projected increase in loading. The characterization of dissolved inorganic nitrogen (DIN) and DON processing from groundwater to surface water also remains unconstrained. This study attempts to fill in these knowledge gaps by quantifying the DON pool and potential sources in a semiarid, low inflow estuary (Baffin Bay, Texas) using stable isotope techniques.

Modern analogs for ammonia flux from terrestrial hydrothermal features to the Archean atmosphere.

The isotopic composition of nitrogen in the rock record provides valuable evidence of reactive nitrogen sources and processing on early Earth, but the wide range of δN values (- 10.2 to + 50.4‰) leads to ambiguity in defining the early Precambrian nitrogen cycle.

Determining organic nitrogen emission sources and secondary formations in an urban coastal airshed via stable isotope techniques.

Organic nitrogen (ON) has been excluded in the majority of atmospheric N studies. However, dissolved organic nitrogen (DON) deposition influences coastal water quality and primary production creating an urgent need for comprehensive atmospheric ON characterization, especially in coastal airsheds. This study measured the concentration and isotopic composition of rainwater DON (δN-DON) and applied stable isotope mixing models to determine the ON emission source apportionments in a small-sized coastal city.

Apportioning Atmospheric Ammonia Sources across Spatial and Seasonal Scales by Their Isotopic Fingerprint.

Mitigating ammonia (NH) emissions is a significant challenge, given its well-recognized role in the troposphere, contributing to secondary particle formation and impacting acid rain. The difficulty arises from the highly uncertain attribution of atmospheric NH to specific emission sources, especially when accounting for diverse environments and varying spatial and temporal scales. In this study, we established a refined δN fingerprint for eight emission sources, including three previously overlooked sources of potential importance.

Rewilding in Miniature: Suburban Meadows Can Improve Soil Microbial Biodiversity and Soil Health.

Lawns are a ubiquitous, human-made environment created for human enjoyment, leisure, and aesthetics. While net positive for carbon storage, lawns can have negative environmental impacts. Lawns require frequent mowing, which produces high levels of CO pollution and kills off native plants.

Nitrogen isotopes indicate vehicle emissions and biomass burning dominate ambient ammonia across Colorado's Front Range urban corridor.

Urban ammonia (NH) emissions contribute to poor local air quality and can be transported to rural landscapes, impacting sensitive ecosystems. The Colorado Front Range urban corridor encompasses the Denver Metropolitan Area, rural farmland/rangeland and montane forest between the city and the Rocky Mountains. Reactive nitrogen emissions from the corridor are partly responsible for increased N deposition to the wildland-urban interface (WUI) in this region.

Hurricane/tropical storm rainwater chemistry in the US (from 2008 to 2019).

Rainwater chemistry of extreme rain events is not well characterized. This is despite an increasing trend in intensity and frequency of extreme events and the potential excess loading of elements to ecosystems that can rival annual loading. Thus, an assessment of the loading imposed by hurricane/tropical storm (H/TS) can be valuable for future resiliency strategies.

The first complete mitochondrial genome of the migratory dragonfly Fabricius, 1798 (Libellulidae: Odonata).

is the world's most abundant and widely distributed dragonfly and with its outstanding migratory capacity an important model system to study insect migration at the evolutionary base of winged insects. We here report on the first complete mitochondrial genome (mitogenome) of sampled from a population in Rufiji River, Tanzania. The mitogenome is 14,853 bp long with an AT-biased base composition (72.

Seasonal pattern of ammonium N natural abundance in precipitation at a rural forested site and implications for NH source partitioning.

Excess ammonia (NH) emissions and deposition can have negative effects on air quality and terrestrial ecosystems. Identifying NH sources is a critical step for effectively reducing NH emissions, which are generally unregulated around the world. Stable nitrogen isotopes (δN) of ammonium (NH) in precipitation have been directly used to partition NH sources.

Compound-Specific Carbon Isotopic Composition of Ethanol in Brazil and US Vehicle Emissions and Wet Deposition.

Global atmospheric ethanol budget models include large uncertainties in the magnitude of ethanol emission sources and sinks. To apply stable isotope techniques to constrain ethanol emission sources, a headspace solid phase microextraction gas chromatograph-combustion-isotope ratio mass spectrometry method (HS-SPME-GC-C-IRMS) was developed to measure the carbon isotopic composition of aqueous phase ethanol at natural abundance levels (1-30 μM) with a precision of 0.4‰.

Variability of ethanol concentration in rainwater driven by origin versus season in coastal and inland North Carolina, USA.

Rainwater ethanol concentrations were measured for one year (June 2013-May 2014) in central (Elon, NC) and coastal (Wilmington, NC) North Carolina, allowing for a comparison of the effects of coastal and marine rain on ethanol concentration and deposition both at the coast and 250 km inland. Rain samples were collected on an event basis and analyzed using enzyme oxidation and headspace solid-phase microextraction (HS-SPME). The volume-weighted average ethanol concentration at Elon (609 ± 116 nM) was higher than at Wilmington (208 ± 21 nM).

Surface waters as a sink and source of atmospheric gas phase ethanol.

This study reports the first ethanol concentrations in fresh and estuarine waters and greatly expands the current data set for coastal ocean waters. Concentrations for 153 individual measurements of 11 freshwater sites ranged from 5 to 598 nM. Concentrations obtained for one estuarine transect ranged from 56 to 77 nM and levels in five coastal ocean depth profiles ranged from 81 to 334 nM.

Temporal and spatial variability of trace volatile organic compounds in rainwater.

This study presents the first detailed concentration profile of trace VOCs in atmospheric waters. Analytes were detected and quantified in 111 unique rain events in Wilmington, NC, USA over a one-year period. Headspace solid phase microextraction was optimized for detection of these compounds at sub-nanomolar levels.

Characterizing the isotopic composition of atmospheric ammonia emission sources using passive samplers and a combined oxidation-bacterial denitrifier approach.

Rationale: Ammonia (NH3) emissions are a substantial source of nitrogen pollution to sensitive terrestrial, aquatic, and marine ecosystems and dependable quantification of NH3 sources is of growing importance due to recently observed increases in ammonium (NH4(+)) deposition rates. While determination of the nitrogen isotopic composition of NH3 (δ(15)N-NH3) can aid in the quantification of NH3 emission sources, existing methods have precluded a comprehensive assessment of δ(15)N-NH3 values from major emission sources.

Methods: We report an approach for the δ(15)N-NH4(+) analysis of low concentration NH4(+) samples that couples the bromate oxidation of NH4(+) to NO2(-) and the microbial denitrifier method for δ(15)N-NO2(-) analysis.

Nitrogen isotopic composition of coal-fired power plant NOx: influence of emission controls and implications for global emission inventories.

Despite the potential use of δ(15)N as a tracer of NO(x) source contributions, prior documentation of δ(15)N of various NO(x) emission sources is exceedingly limited. This manuscript presents the first measurements of the nitrogen isotopic composition of NO(x) (δ(15)N-NO(x)) emitted from coal-fired power plants in the U.S.