The role of a changing Arctic Ocean and climate for the biogeochemical cycling of dimethyl sulphide and carbon monoxide

Dimethyl sulphide (DMS) and carbon monoxide (CO) are climate-relevant trace gases that play key roles in the radiative budget of the Arctic atmosphere. Under global warming, Arctic sea ice retreats at an unprecedented rate, altering light penetration and biological communities, and potentially affect DMS and CO cycling in the Arctic Ocean. This could have socio-economic implications in and beyond the Arctic region. However, little is known about CO production pathways and emissions in this region and the future development of DMS and CO cycling. Here we summarize the current understanding and assess potential future changes of DMS and CO cycling in relation to changes in sea ice coverage, light penetration, bacterial and microalgal communities, pH and physical properties. We suggest that production of DMS and CO might increase with ice melting, increasing light availability and shifting phytoplankton community. Among others, policy measures should facilitate large-scale process studies, coordinated long term observations and modelling efforts to improve our current understanding of the cycling and emissions of DMS and CO in the Arctic Ocean and of global consequences.

Hayıt (Vitex agnus-castus L.) Ballarının Uçucu Bileşenlerinin ve Duyusal Özelliklerinin Tanımlanması

In this study, it was aimed to characterize some physical and chemical properties, volatile compounds and sensory properties of chaste honey produced in Aydın, Çanakkale, İzmir and Muğla provinces. A total of 16 different volatile compounds (4 aldehydes, 3 furans, 2 alcohol, 2 sulphur compounds, 2 terpenes, 1 alkane, 1 benzenic compound and 1 ketone) were identified in the evaluated chaste honeys. It was determined that common volatile compounds of chaste honeys were dimethyl sulphide, octane, nonanal, 2-furancarboxaldehyde, 2-ethyl-1-hexanol, 1- (2-furanyl) -ethanone, benzaldehyde, 5-methyl-2-furancarboxaldehyde, and benzenacetaldehyde. Benzenacetaldehyde was the most abundant volatile compound in all chaste honeys, followed by benzaldehyde and 2-furancarboxaldehyde. As a result of the sensory evaluation, floral, fruity, caramel-like, bitter almond, fermented, animal-like, spicy, waxy, and woody aroma characters, sweet and sour taste characters and astringent mouthfeeling were detected in chaste honeys. The floral, fruity, caramel-like, sweet, and sour characters were intensely perceived in all samples.

Third Revision of the Bottom-up Global Surface Seawater Dimethyl Sulphide Climatology (DMS-Rev3)

<p>An updated estimation of the bottom-up global surface seawater dimethyl sulphide (DMS) climatology, DMS-Rev3, is the third of its kind and includes five significant changes from the last climatology, ‘L11’ (Lana et al., 2011) that was released about a decade ago. The first change is the inclusion of new observations that have become available over the last decade, i.e., the total number of observations included in DMS- Rev3 are 865,109 as compared to 47,313 data points used in the last estimation (~1728% increase in raw data). The second was significant improvements in data handling, processing, filtering, to avoid bias due to different observation frequencies. Thirdly, we incorporated the dynamic seasonal changes observed in the ocean biogeochemical provinces and their variable geographic boundaries. Fourth change was refinements in the interpolation algorithm used to fill up the missing data. And finally, an upgraded smoothing algorithm based on observed DMS variability length scales (VLS) which helped reproduce a more realistic distribution of the DMS concentration data. The results show that DMS-Rev3 estimates the global annual mean DMS concentration at 2.34 nM, 4% lower than the current bottom-up ‘L11’ climatology. However, significant regional differences of more than 100% are observed. The largest changes are observed in high concentration regions such as the polar oceans, although oceanic regions which were under-sampled in the past also show large differences. DMS-Rev3 reduces the previously observed patchiness in high productivity regions.</p>

Volatile Changes during Storage of Shelf Stable Apple Juice: Integrating GC-MS Fingerprinting and Chemometrics

This is the first study to reveal potential markers for volatile changes during ambient and accelerated shelf life of pasteurized apple juice. The volatile changes were monitored at 20, 30 and 40 °C using a headspace solid-phase microextraction-gas chromatography-mass spectrometry fingerprinting method. Using modern chemometrics and feature selection, hexanal, trans-2-hexenal, dimethyl sulphide, furfural, ethyl acetate and 1-pentanol were chosen as potential shelf life markers. Volatiles associated with the green, grassy and fresh apple aroma, such as hexanal and trans-2-hexenal, decreased during storage, whereas thermal load and browning associated compounds, like dimethyl sulphide and furfural, increased during storage. Hexanal and trans-2-hexenal can be markers to monitor the change in green-apple like character. Furfural and dimethyl sulphide can be markers of temperature abuse during juice processing and storage. Furfural can also be an indicator for juice browning. The present work effectively identified potential markers to monitor and predict volatile aroma changes of shelf stable apple juice in different storage conditions. Sensory analysis can be conducted in the future to confirm the aroma relevance of selected markers.

On the annual variability of Antarctic aerosol size distributions at Halley research station

The Southern Ocean and Antarctic region currently best represent one of the few places left on our planet with conditions similar to the preindustrial age. Currently, climate models have low ability to simulate conditions forming the aerosol baseline; a major uncertainty comes from the lack of understanding of aerosol size distributions and their dynamics. Contrasting studies stress that primary sea-salt aerosol can contribute significantly to the aerosol population, challenging the concept of climate biogenic regulation by new particle formation (NPF) from dimethyl sulphide marine emissions. We present a statistical cluster analysis of the physical characteristics of particle size distributions (PSD) collected at Halley (Antarctica) for the year 2015 (89 % data coverage). By applying the Hartigan-Wong k-Means method we find 8 clusters describing the entire aerosol population. Three clusters show pristine average low particle number concentrations (

Kuantifikasi Kandungan Volatile Organic Compounds (VOC) di Kawasan Desa Sungai Rambe untuk Memprediksi Keberadaan Minyak Bumi

Penelitian ini menggunakan metode Gore Sorber dengan menanamkan alat ke dalam tanah selama 21 hari dan pada hari ke-21 alat tersebut diambil kemudian kandungannya dianalisis dengan menggunakan GC-MS untuk mengetahui jumlah senyawa hidrokarbon yang terkandung dalam minyak bumi. Beberapa senyawa yang terdeteksi dengan metode Gore Sorber diantaranya adalah alfa pinena, dimetil sulfida, karbonil sulfide, dimetil disulfida, butana dana etana. Senyawa tersebut merupakan senyawa yang umum ditemukan pada minyak bumi dengan komposisi alfa pinena 206,34 ng; dimetil sulfida 196,65 ng; dan dimetil disulfida 205,8 ng. Tiga komponen tersebut merupakan komponen minyak bumi hidrokarbon dan non-hidrokarbon. This research uses Gore Sorber method by implanting the tool into the soil for 21 days then taken on day 21 and directly analyzed using GC-MS instrument to know the amount of hydrocarbon compound contained in petroleum. Some of the compounds detected using Gore-Sorber are alpha pinene, dimethyl sulphide, carbonyl sulphide, dimethyl disulfide, butane and ethane. These components are typical of petroleum compounds seen from the highest components of alpha pinene 206.34 ng, dimethyl sulfide 196.65 ng and dimethyl disulfide 205.8 ng. The three components are petroleum components of hydrocarbons and non-hydrocarbons.