Seasonal changes of sources and volatility of carbonaceous aerosol at urban, coastal and forest sites in Eastern Europe (Lithuania)

We measured stable carbon isotope ratios of total carbon (TC) and organic carbon (OC) in fine carbonaceous aerosol fraction sampled in August and September 2013 at urban, coastal and forest sites in Lithuania. δ13C values of TC for all three sites over the whole measurement period varied from −29.3 to −26.6‰, which is in the range of particles emitted by fossil fuel combustion in Eastern Europe. The isotopic composition at the forest and coastal site showed a similar variation during two contrasting pollution periods. δ13C values in the clean period were more variable, whereas the polluted period was characterized by a gradual enrichment in δ13C compared to the clean period. In the polluted period air masses originated from southern, southeastern or southwestern direction, indicating long-range transport of pollutants from Eastern Europe and Southern Europe to Lithuania. Oxidative processing during long-range transport or the different source signatures (e.g., enriched 13C signature of gasoline used in Western Europe vs. Eastern Europe) could cause the less negative δ13COC values during the polluted episode. δ13C for OC desorbed from the filter samples was separately measured during three different temperature steps (200 °C, 350 °C and 650 °C). OC desorbed at 200 °C had the most depleted 13C signature of around −29‰ at all three sites. A comparison with previously published data measured during the winter at the same sites showed that both TC and OC had less negative δ13C values in winter than in summer, which can be explained by the contribution of biomass/coal burning sources in winter. At the urban site δ13C of OC did not change much with increasing desorption temperature in winter, which is typical for primary sources, but in the summer δ13C of OC was depleted for lower desorption temperatures, possibly due to the influence of SOA formation. A higher fraction of more refractory OC in summer compared to winter-time suggests active photochemical processing of the primary organic aerosol as an important process at all three sites

Stable carbon and nitrogen isotope ratio in PM1 and size segregated aerosol particles over the Baltic Sea

We analysed delta C-13 of total carbon (TC) and PN of total nitrogen (TN) in submicron (PM1) and size segregated aerosol particles ( PM0.056-2.5) collected during a cruise in the Baltic Sea from 9 to 17 November 2012. PM1 were characterized by the highest delta C-13 (-26.4 parts per thousand) and lowest delta N-15 (-0.2 and 0.8 parts per thousand) values when air masses arrived from the southwest direction (Poland). The obtained delta C-13 values indicated that combined emissions of coal and diesel/gasoline combustion were the most likely sources of TC. The depleted delta N-15 values indicated that TN originated mainly from liquid fuel combustion (road traffic, shipping) during this period. The lowest PC and highest delta N-15 values were determined in PM1 samples during the western airflow when the air masses had no recent contact with land. The highest delta N-15 values were probably associated with chemical aging of nitrogenous species during long-range transport, the lowest delta C-13 values could be related to emissions from diesel/gasoline combustion, potentially from ship traffic. The delta C-13 analysis of size-segregated aerosol particles PM0.056-2.5 revealed that the lowest delta C-13 values were observed in the size range from 0.056 to 0.18 mu m and gradual C-13 enrichment occurred in the size range from 0.18 to 2.5 mu m due to different sources or formation mechanisms of the aerosols

Diagnostics of new species of Neotropical Tischeriidae (Lepidoptera), with the first record of Coptotriche Walshingham from South America

We describe seven new Neotropical species of Tischeriidae: Astrotischeria dondavisi Stonis & Diškus, sp. nov., A. bacchariphaga Diškus & Stonis, sp. nov., A. guatemalica Diškus & Stonis, sp. nov., A. sanjosei Stonis & Diškus, sp. nov., A. truncata Diškus & Stonis, sp. nov., Coptotriche parvisacculata Diškus & Stonis, sp. nov. and C. carmencita Stonis & Diškus, sp. nov. We report the discovery of Coptotriche Walsingham in South America and provide the following new host-plant records for the Neotropical Tischeriidae: Terminalia australis Cambess. (Combretaceae), Baccharis latifolia (Ruiz & Pav.) Pers., and B. emarginata (Ruiz & Pav.) Pers. (Asteraceae). We update the biology of Astrotischeria ochrimaculosa Diškus, Stonis & Vargas with the discovery that Wissadula (Malvaceae) is a new, verified host plant. The new species are illustrated with photographs of the adults, male and, if available, female genitalia, and the leaf mines. We expect broader distributions of tisheriid species in South America inferred from known host-plant distributions.Fil: Stonis, Jonas R.. Vytautas Magnus University; LituaniaFil: Diskus, Arunas. Vytatutas Magnus University; LituaniaFil: Remeikis, Andrius. Nature Research Centre and Baltic-American Biotaxonomy Institute; LituaniaFil: Katinas, Liliana. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División de Plantas Vasculares; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Torres, Nixon Cumbicus. Universidad Tecnica Particular de Loja; EcuadorFil: Schuster, Jack. Universidad del Valle de Guatemala; GuatemalaFil: Puplesyte Chambers, Julia. No especifíca

delta C-13 signatures of organic aerosols:Measurement method evaluation and application in a source study

Analysis of the stable carbon isotope 13C in organic carbon (OC) can give insight into sources and atmospheric processing of carbonaceous aerosols, provided the 13C source signatures are known. However, only few data on 13C signatures of OC emitted by common sources of carbonaceous aerosol are available in Europe. We present and evaluate an improved version of a measurement method to obtain δ13C signatures on organic aerosols desorbed from filter samples at three different desorption temperatures (200 °C, 350 °C and 650 °C) and apply it in a source study. With our calibration approach, the reproducibility of a L-Valine reference material desorbed at a single temperature step of 650 °C shows a standard deviation of 0.19‰ over a period of more than one year. The average δ13C value for this reference material over 248 measurements is −24.10‰, which shows only a slight bias to the nominal value of −24.03‰. Repeated analysis of ambient filter samples desorbed at three temperature steps show typical standard deviations of about 0.3‰ for all temperature steps (200 °C, 350 °C and 650 °C). Isotopic fractionation due to partial thermal desorption during the individual temperature steps was tested on single compound reference materials. It showed significant isotopic fractionation only at temperature steps, in which a very minor fraction of the compound was desorbed. Possible isotope effects caused by charring of organic material were investigated and found to be not significant. The thermal desorption method was applied to various source filter samples from the region of Naples, Italy. We analyzed two different biomass burning sources, exhaust from a city bus and traffic emissions collected in a tunnel and compared these to ambient filter samples from the same region. δ13C signatures of the total OC show values in a narrow range of about −28‰ to −26‰ for all sources, which does not allow a source apportionment only based on 13C. Nevertheless, the results add information to a source inventory of δ13C, where information of 13C in organic aerosol from specific emission sources are rare. City bus emissions show little variation of δ13C over the temperature steps, whereas biomass burning aerosol is enriched in 13C for OC desorbed at 650 °C. For PM10 samples in the urban tunnel an enrichment in δ13C at the 650 °C temperature steps was observed, which is likely caused by the contribution of carbonate carbon to the carbonaceous material desorbed at this temperature step

Immediate increase in isotopic enrichment in small mammals following the expansion of a great cormorant colony

Colonies of great cormorants (Phalacrocorax carbo) impact terrestrial ecosystems through the transport of nutrients from aquatic to terrestrial ecosystems. Deposited guano overload the ecosystem with N and P, change soil pH and damage vegetation. The ways in which small mammals are impacted, however, are little known. We aimed to evaluate the effects of an expanding great cormorant colony, testing if the expansion immediately increased the input of biogens into the forest ecosystem and, further, if the growing influence of the colony was reflected in basal resources (plants and invertebrates) and the hair of small mammals. δ15N and δ13C signatures were analyzed in granivorous yellow-necked mice (Apodemus flavicollis), omnivorous bank voles (Myodes glareolus) and basal resources of animal and plant origin from the territory of a colony of great cormorants situated near the Baltic Sea in west Lithuania. We found that biogens transferred by great cormorants to the terrestrial ecosystem affected the potential foods of the small mammals and led to highly elevated and variable δ15N values. An increase of the size of the colony in 2015 resulted in isotopic enrichment of the small mammals in the zone of expansion in comparison to levels in 2014. The increase of δ15N in A. flavicollis was 7.5 % (p < 0.05) in the ecotone and 5.7 % in the expansion zone. The decrease in δ13C signatures in A. flavicollis was 4.5 % (p < 0.1) in the expansion zone and 3.1 % (p < 0.001) in the colony. In M. glareolus, the decrease in δ13C signatures was 8.5 % in the expansion zone, 3.3 % (p < 0.1) in the control zone and 2.6 % in the ecotone. Isotopic niches (central ellipses) of A. flavicollis in the colony and between the control and expansion zones were separated in 2014 and 2015, while they partially overlapped in the ecotone. The isotopic niches of M. glareolus in 2014 and 2015 were separated in the ecotone and had a small overlap in the colony. For most of the resources tested, the isotopic signatures in the established colony area were significantly higher than in the rest of cormorant-inhabited area. In the colony, the δ15N values in plants (16.9 ± 1.1 ‰) were higher than in invertebrates (13.6 ± 0.4 ‰). In the ecotone, the δ15N values were 12.0 ± 1.4 in plants and 14.7 ± 0.04 ‰ in invertebrates, while in the expansion zone they were 7.2 ± 3.0 and 9.9 ± 3.8 ‰, respectively. δ15N-rich resources led to increased δ15N values in the hair of A. flavicollis and M. glareolus. Thus, biogens from the great cormorant colony immediately affected small mammals through their food sources