Quantitative identification of non-point sources of nitrate in urban channels based on dense in-situ samplings and nitrate isotope composition

Chemosphere ◽  
2021 ◽  
Vol 263 ◽  
pp. 128219
Author(s):  
Jiaxun Guo ◽  
Ping Zuo ◽  
Long Yang ◽  
Ye Pan ◽  
Lachun Wang
Keyword(s):  
Isotope Composition ◽  
Point Sources ◽  
Quantitative Identification ◽  
Nitrate Isotope

Origin of Monte Rosa whiteschist from in-situ tourmaline and quartz oxygen isotope analysis by SIMS using new tourmaline reference materials

2019 ◽  
Vol 104 (10) ◽  
pp. 1503-1520 ◽  
Author(s):  
Katharina Marger ◽  
Cindy Luisier ◽  
Lukas P. Baumgartner ◽  
Benita Putlitz ◽  
Barbara L. Dutrow ◽  
...  
Keyword(s):  
High Pressure ◽  
Oxygen Isotope ◽  
Reference Materials ◽  
Secondary Ion Mass Spectrometry ◽  
Isotope Composition ◽  
Isotope Analysis ◽  
Oxygen Isotope Composition ◽  
The Matrix ◽  
Monte Rosa

Abstract A series of tourmaline reference materials are developed for in situ oxygen isotope analysis by secondary ion mass spectrometry (SIMS), which allow study of the tourmaline compositions found in most igneous and metamorphic rocks. The new reference material was applied to measure oxygen isotope composition of tourmaline from metagranite, meta-leucogranite, and whiteschist from the Monte Rosa nappe (Western Alps). The protolith and genesis of whiteschist are highly debated in the literature. Whiteschists occur as 10 to 50 m tube-like bodies within the Permian Monte Rosa granite. They consist of chloritoid, talc, phengite, and quartz, with local kyanite, garnet, tourmaline, and carbonates. Whiteschist tourmaline is characterized by an igneous core and a dravitic overgrowth (XMg > 0.9). The core reveals similar chemical composition and zonation as meta-leucogranitic tourmaline (XMg = 0.25, δ18O = 11.3–11.5‰), proving their common origin. Dravitic overgrowths in whiteschists have lower oxygen isotope compositions (8.9–9.5‰). Tourmaline in metagranite is an intermediate schorl-dravite with XMg of 0.50. Oxygen isotope data reveal homogeneous composition for metagranite and meta-leucogranite tourmalines of 10.4–11.3‰ and 11.0–11.9‰, respectively. Quartz inclusions in both meta-igneous rocks show the same oxygen isotopic composition as the quartz in the matrix (13.6–13.9‰). In whiteschist the oxygen isotope composition of quartz included in tourmaline cores lost their igneous signature, having the same values as quartz in the matrix (11.4–11.7‰). A network of small fractures filled with dravitic tourmaline can be observed in the igneous core and suggested to serve as a connection between included quartz and matrix, and lead to recrystallization of the inclusion. In contrast, the igneous core of the whiteschist tourmaline fully retained its magmatic oxygen isotope signature, indicating oxygen diffusion is extremely slow in tourmaline. Tourmaline included in high-pressure chloritoid shows the characteristic dravitic overgrowth, demonstrating that chloritoid grew after the metasomatism responsible for the whiteschist formation, but continued to grow during the Alpine metamorphism. Our data on tourmaline and quartz show that tourmaline-bearing white-schists originated from the related meta-leucogranites, which were locally altered by late magmatic hydrothermal fluids prior to Alpine high-pressure metamorphism.

scholarly journals Two eyes for two purposes: in situ evidence for asymmetric vision in the cockeyed squids Histioteuthis heteropsis and Stigmatoteuthis dofleini

2017 ◽  
Vol 372 (1717) ◽  
pp. 20160069 ◽  
Author(s):  
Kate N. Thomas ◽  
Bruce H. Robison ◽  
Sönke Johnsen
Keyword(s):  
Submarine Canyon ◽  
Point Sources ◽  
Video Footage ◽  
Eye Size ◽  
Yellow Pigmentation ◽  
Left And Right ◽  
Dim Light ◽  
Different Sources ◽  
High Diversity

The light environment of the mesopelagic realm of the ocean changes with both depth and viewer orientation, and this has probably driven the high diversity of visual adaptations found among its inhabitants. The mesopelagic ‘cockeyed’ squids of family Histioteuthidae have unusual eyes, as the left and right eyes are dimorphic in size, shape and sometimes lens pigmentation. This dimorphism may be an adaptation to the two different sources of light in the mesopelagic realm, with the large eye oriented upward to view objects silhouetted against the dim, downwelling sunlight and the small eye oriented slightly downward to view bioluminescent point sources. We used in situ video footage from remotely operated vehicles in the Monterey Submarine Canyon to observe the orientation behaviour of 152 Histioteuthis heteropsis and nine Stigmatoteuthis dofleini . We found evidence for upward orientation in the large eye and slightly downward orientation in the small eye, which was facilitated by a tail-up oblique body orientation. We also found that 65% of adult H. heteropsis ( n = 69) had yellow pigmentation in the lens of the larger left eye, which may be used to break the counterillumination camouflage of their prey. Finally, we used visual modelling to show that the visual returns provided by increasing eye size are much higher for an upward-oriented eye than for a downward-oriented eye, which may explain the development of this unique visual strategy. This article is part of the themed issue ‘Vision in dim light’.

scholarly journals Characterization of satellite based proxies for estimating nucleation mode particles over South Africa

2014 ◽  
Vol 14 (18) ◽  
pp. 25825-25867
Author(s):  
A.-M. Sundström ◽  
A. Nikandrova ◽  
K. Atlaskina ◽  
T. Nieminen ◽  
V. Vakkari ◽  
...  
Keyword(s):  
South Africa ◽  
Industrial Area ◽  
Particle Formation ◽  
Point Sources ◽  
New Particle Formation ◽  
Factors Affecting ◽  
Nucleation Mode ◽  
Sink Term ◽  
Major Factors

Abstract. In this work satellite observations from the NASA's A-Train constellation were used to derive the values of primary emission and regional nucleation proxies over South Africa to estimate the potential for new particle formation. As derived in Kulmala et al. (2011), the satellite based proxies consist of source terms (NO2, SO2 and UV-B radiation), and a sink term describing the pre-existing aerosols. The first goal of this work was to study in detail the use of satellite aerosol optical depth (AOD) as a substitute to the in situ based condensation sink (CS). One of the major factors affecting the agreement of CS and AOD was the elevated aerosol layers that increased the value of column integrated AOD but not affected the in situ CS. However, when the AOD in the proxy sink was replaced by an estimate from linear bivariate fit between AOD and CS, the agreement with the actual nucleation mode number concentration improved somewhat. The second goal of the work was to estimate how well the satellite based proxies can predict the potential for new particle formation. For each proxy the highest potential for new particle formation were observed over the Highveld industrial area, where the emissions were high but the sink due to pre-existing aerosols was relatively low. Best agreement between the satellite and in situ based proxies were obtained for NO2/AOD and UV-B/AOD2, whereas proxies including SO2 in the source term had lower correlation. Even though the OMI SO2 boundary layer product showed reasonable spatial pattern and detected the major sources over the study area, some of the known minor point sources were not detected. When defining the satellite proxies only for days when new particle formation event was observed, it was seen that for all the satellite based proxies the event day medians were higher than the entire measurement period median.

scholarly journals Development and characterization of a mobile γ spectrometer and its field deployment for in situ radioactivity measurements

2021 ◽  
Vol 7 (2) ◽  
pp. 157-164
Author(s):  
T. J. Mertzimekis ◽  
C. Andrikopoulos ◽  
C. Fakiola ◽  
A. Kotsovolou ◽  
D. Lampridou ◽  
...  
Keyword(s):  
Point Sources ◽  
Chernobyl Fallout ◽  
Test Operation ◽  
Custom Made ◽  
Absolute Efficiency ◽  
Field Deployment ◽  
Γ Spectrometer ◽  
Trace Concentrations ◽  
The University

A mobile γ–ray spectrometer (AMESOS) has been developed using a 3”×3” NaI(Tl) detector, a custom–made mounting holder, and portable electronics to perform in situ measurements of radioactivity. The spectrometer was calibrated using standard point sources and its absolute efficiency was determined. As a field test operation, AMESOS was deployed on the premises of the University of Athens Zografou campus focusing on estimating the NORM levels. Data were analyzed and used to create radiological maps for the metropolitan UoA campus for the first time. Besides natural radioactivity levels, trace concentrations of 137Cs were also detected, attributed to the Chernobyl fallout in Greece. An overall steady performance of the spectrometer was observed throughout the field operation. AMESOS is ready to be deployed for in situ studies of environmental radioactivity and radwaste management.

scholarly journals Geochemical characteristics of back-arc basin lower crust and upper mantle at final spreading stage of Shikoku Basin: an example of Mado Megamullion

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Norikatsu Akizawa ◽  
Yasuhiko Ohara ◽  
Kyoko Okino ◽  
Osamu Ishizuka ◽  
Hiroyuki Yamashita ◽  
...  
Keyword(s):  
Isotope Composition ◽  
Spreading Center ◽  
Chemical Compositions ◽  
Olivine Gabbro ◽  
Pb Isotope ◽  
Shikoku Basin ◽  
Source Mantle ◽  
Evolutional Process ◽  
Back Arc

AbstractThis paper explores the evolutional process of back-arc basin (BAB) magma system at final spreading stage of extinct BAB, Shikoku Basin (Philippine Sea) and assesses its tectonic evolution using a newly discovered oceanic core complex, the Mado Megamullion. Bulk and in-situ chemical compositions together with in-situ Pb isotope composition of dolerite, oxide gabbro, gabbro, olivine gabbro, dunite, and peridotite are presented. Compositional ranges and trends of the igneous and peridotitic rocks from the Mado Megamullion are similar to those from the slow- to ultraslow-spreading mid-ocean ridges (MOR). Since the timing of the Mado Megamullion exhumation corresponds to the very end of the Shikoku Basin opening, the magma supply was subdued and highly episodic, leading to extreme magma differentiation to form ferrobasaltic, hydrous magmas. In-situ Pb isotope composition of magmatic brown amphibole in the oxide gabbro is identical to that of depleted source mantle for mid-ocean ridge basalt (MORB). In the context of hydrous BAB magma genesis, the magmatic water was derived solely from the MORB source mantle. The distance from the back-arc spreading center to the arc front increased away through maturing of the Shikoku Basin to cause MORB-like magmatism. After the exhumation of Mado Megamullion along detachment faults, dolerite dikes intruded as a post-spreading magmatism. The final magmatism along with post-spreading Kinan Seamount Chain volcanism were introduced around the extinct back-arc spreading center after the opening of Shikoku Basin by residual mantle upwelling.

scholarly journals Near real time water quality monitoring of Chivero and Manyame lakes of Zimbabwe

2018 ◽  
Vol 378 ◽  
pp. 85-92 ◽  
Author(s):  
Ronald Muchini ◽  
Webster Gumindoga ◽  
Sydney Togarepi ◽  
Tarirai Pinias Masarira ◽  
Timothy Dube
Keyword(s):  
Water Quality ◽  
Water Quality Monitoring ◽  
Remotely Sensed ◽  
Quality Parameters ◽  
Point Sources ◽  
Water Quality Parameters ◽  
Quality Monitoring ◽  
Quality Information ◽  
Web Portal

Abstract. Zimbabwe's water resources are under pressure from both point and non-point sources of pollution hence the need for regular and synoptic assessment. In-situ and laboratory based methods of water quality monitoring are point based and do not provide a synoptic coverage of the lakes. This paper presents novel methods for retrieving water quality parameters in Chivero and Manyame lakes, Zimbabwe, from remotely sensed imagery. Remotely sensed derived water quality parameters are further validated using in-situ data. It also presents an application for automated retrieval of those parameters developed in VB6, as well as a web portal for disseminating the water quality information to relevant stakeholders. The web portal is developed, using Geoserver, open layers and HTML. Results show the spatial variation of water quality and an automated remote sensing and GIS system with a web front end to disseminate water quality information.

scholarly journals A new global anthropogenic SO<sub>2</sub> emission inventory for the last decade: a mosaic of satellite-derived and bottom-up emissions

2018 ◽  
Vol 18 (22) ◽  
pp. 16571-16586 ◽  
Author(s):  
Fei Liu ◽  
Sungyeon Choi ◽  
Can Li ◽  
Vitali E. Fioletov ◽  
Chris A. McLinden ◽  
...  
Keyword(s):  
Emission Inventory ◽  
Correlation Coefficients ◽  
In Situ Measurements ◽  
Point Sources ◽  
Ozone Monitoring Instrument ◽  
So2 Emissions ◽  
Bottom Up ◽  
Earth Observing System ◽  
The Us

Abstract. Sulfur dioxide (SO2) measurements from the Ozone Monitoring Instrument (OMI) satellite sensor have been used to detect emissions from large point sources. Emissions from over 400 sources have been quantified individually based on OMI observations, accounting for about a half of total reported anthropogenic SO2 emissions. Here we report a newly developed emission inventory, OMI-HTAP, by combining these OMI-based emission estimates and the conventional bottom-up inventory, HTAP, for smaller sources that OMI is not able to detect. OMI-HTAP includes emissions from OMI-detected sources that are not captured in previous leading bottom-up inventories, enabling more accurate emission estimates for regions with such missing sources. In addition, our approach offers the possibility of rapid updates to emissions from large point sources that can be detected by satellites. Our methodology applied to OMI-HTAP can also be used to merge improved satellite-derived estimates with other multi-year bottom-up inventories, which may further improve the accuracy of the emission trends. OMI-HTAP SO2 emissions estimates for Persian Gulf, Mexico, and Russia are 59 %, 65 %, and 56 % larger than HTAP estimates in 2010, respectively. We have evaluated the OMI-HTAP inventory by performing simulations with the Goddard Earth Observing System version 5 (GEOS-5) model. The GEOS-5 simulated SO2 concentrations driven by both HTAP and OMI-HTAP were compared against in situ measurements. We focus for the validation on 2010 for which HTAP is most valid and for which a relatively large number of in situ measurements are available. Results show that the OMI-HTAP inventory improves the agreement between the model and observations, in particular over the US, with the normalized mean bias decreasing from 0.41 (HTAP) to −0.03 (OMI-HTAP) for 2010. Simulations with the OMI-HTAP inventory capture the worldwide major trends of large anthropogenic SO2 emissions that are observed with OMI. Correlation coefficients of the observed and modeled surface SO2 in 2014 increase from 0.16 (HTAP) to 0.59 (OMI-HTAP) and the normalized mean bias dropped from 0.29 (HTAP) to 0.05 (OMI-HTAP), when we updated 2010 HTAP emissions with 2014 OMI-HTAP emissions in the model.

scholarly journals Variations in triple isotope composition of dissolved oxygen and primary production in a subtropical reservoir

2016 ◽  
Vol 13 (24) ◽  
pp. 6683-6698 ◽  
Author(s):  
Hana Jurikova ◽  
Tania Guha ◽  
Osamu Abe ◽  
Fuh-Kwo Shiah ◽  
Chung-Ho Wang ◽  
...  
Keyword(s):  
Primary Production ◽  
Isotope Composition ◽  
Environmental Parameters ◽  
Order Of Magnitude ◽  
Lakes And Reservoirs ◽  
Net To Gross ◽  
Feitsui Reservoir ◽  
Incubation Method ◽  
Mass Balance Approach

Abstract. Lakes and reservoirs play an important role in the carbon cycle, and therefore monitoring their metabolic rates is essential. The triple oxygen-isotope anomaly of dissolved O2 [17Δ =  ln(1+δ17O) − 0.518  ×  ln(1 + δ18O)] offers a new, in situ, perspective on primary production, yet little is known about 17Δ from freshwater systems. We investigated the 17Δ together with the oxygen : argon ratio [Δ(O2 ∕ Ar)] in the subtropical Feitsui Reservoir in Taiwan from June 2014 to July 2015. Here, we present the seasonal variations in 17Δ, GP (gross production), NP (net production) and the NP ∕ GP (net to gross ratio) in association with environmental parameters. The 17Δ varied with depth and season, with values ranging between 26 and 205 per meg. The GP rates were observed to be higher (702 ± 107 mg C m−2 d−1) in winter than those (303 ± 66 mg C m−2 d−1) recorded during the summer. The overall averaged GP was 220 g C m−2 yr−1 and NP was −3 g C m−2 yr−1, implying the reservoir was net heterotrophic on an annual basis. This is due to negative NP rates from October to February (−198 ± 78 mg C m−2 d−1). Comparisons between GP rates obtained from the isotope mass balance approach and 14C bottle incubation method (14C–GP) showed consistent values on the same order of magnitude with a GP ∕ 14C–GP ratio of 1.2 ± 1.1. Finally we noted that, although typhoon occurrences were scarce, higher than average 17Δ values and GP rates were recorded after typhoon events.

Towards an integrated study of urban CO2 emissions

2021 ◽  
Author(s):  
Lukas Pilz ◽  
Sanam Vardag ◽  
Ralph Kleinschek ◽  
Samuel Hammer ◽  
André Butz
Keyword(s):  
Performance Improvement ◽  
Urban Areas ◽  
Performance Comparison ◽  
Point Sources ◽  
Performance Ratio ◽  
Weather Research And Forecasting ◽  
Cavity Ringdown ◽  
Simulation Domain ◽  
Integrated Study

&lt;p&gt;High-resolution monitoring is the basis for CO&lt;sub&gt;2&lt;/sub&gt; emissions tracking and attribution in urban areas. This work is an important step towards an integrated urban CO&lt;sub&gt;2&lt;/sub&gt; emissions monitoring system. Three middle-cost nondispersive infrared (NDIR) sensors of 500&amp;#8364; to 3000&amp;#8364; are characterised. Furthermore, CO&lt;sub&gt;2&lt;/sub&gt; emissions of large, regional point sources are simulated to analyse their effect on these sensors&amp;#8217; signals.&lt;/p&gt;&lt;p&gt;The three sensors are Vaisala GMP343, Senseair HPP3 and SmartGas FlowEvo CO&lt;sub&gt;2&lt;/sub&gt;. Their analysis and characterisation is achieved by co-locating them with a Picarro G2401 cavity ringdown spectrometer for 40 days. Co-locating different middle-cost sensors is novel and enables a direct performance comparison. While the HPP3 is the only one to reach a 1 min mean standard deviation under 1 ppm, the GMP343 is the most linear and stable with a drift of 0.03(2) &amp;#215; 10&lt;sup&gt;&amp;#8722;1&lt;/sup&gt; ppm per day and the SmartGas sensor provides the best price-to-performance ratio. For all sensors, precisions (the 1 min mean error&amp;#8217;s lower bound) of under 0.8 ppm are determined. In general, temperature stabilisation turns out to be one of the most promising avenues of performance improvement for all sensors.&lt;/p&gt;&lt;p&gt;The sensors&amp;#8217; in-situ measurements are combined with meso-scale meteorological simulations for the Rhine-Neckar region using the Weather Research and Forecasting model (WRF). In two case-studies, simulated excess CO&lt;sub&gt;2&lt;/sub&gt; due to large, regional point sources and measured CO&lt;sub&gt;2&lt;/sub&gt; concentration are compared. Both simulations show qualitative agreement with the measurements. The differences between measurements and simulation, however, highlight aspects to be refined. These include increasing the horizontal and vertical resolution of the simulation domain as well improving as the parametrisation of the planetary and urban boundary layer.&lt;/p&gt;

Sign in / Sign up

Export Citation Format

Share Document