Declination Zone Research Articles

Understanding the influence of multiple pollutant stressors on the decline of freshwater mussels in a biodiversity hotspot

The Clinch River watershed of the upper Tennessee River Basin of Virginia and Tennessee, USA supports one of North America's greatest concentrations of freshwater biodiversity, including 46 extant species of native freshwater mussels (Order Unionida), 20 of which are protected as federally endangered. Despite the global biological significance of the Clinch River, mussel populations are declining in some reaches, both in species richness and abundance. The aim of this study was to evaluate the exposure of adult resident mussels to a suite of inorganic and organic contaminant stressors in distinct sections of the Clinch River that encompassed a range of mussel abundance and health. To provide insight into the potential role of pollutants in the decline of mussels, including within a previously documented “zone of mussel decline”, the mainstem Clinch River (8 sites) and its tributaries (4 sites) were examined over two consecutive years. We quantified and related metals and organic contaminant concentrations in mussels to their associated habitat compartments (bed sediment, suspended particulate sediment, pore water, and surface water). We found that concentrations of organic contaminants in resident mussels, particularly the suite of 42 polycyclic aromatic hydrocarbons (PAHs) analyzed, were related to PAH concentrations in all four habitat (media) compartments. Further, PAH concentrations in mussel tissue (range 37.8–978.1 ng/g dry weight in 2012 and 194.3–1073.7 ng/g dry weight in 2013) were negatively related to the spatial pattern in mussel densities (rs = −0.64, p ≤ 0.05 in 2012 and rs = −0.83, p ≤ 0.05 in 2013) within the river, and were highest in the “zone of mussel decline”. In contrast, the suite of 22 metals analyzed in resident mussels were largely unrelated to the spatial pattern of variation of metals in the four habitat compartments except for Manganese (Mn; range 3630.5-23,749.2 μg/g dry weight in 2012 and 1540.4-12,605.8 μg/g dry weight in 2013) in surface water (rs = 0.58, p < 0.1) and pore water (rs = 0.76, p ≤ 0.05). This study revealed that PAHs and Mn are important pollutant stressors to mussels in the Clinch River and that they are largely being delivered through the Guest River tributary watershed. Accordingly, future conservation and management efforts would benefit by identifying, and ideally mitigating, the sources of PAHs, Mn, and other current or legacy mining-associated pollutants to the mainstem river and its tributaries.

THE MEXICAN ASTROGRAPHIC CATALOGUE AND CARTE DU CIEL PROJECT

The participation of Mexican astronomers in international projects dates back to the eighteenth century, when they observed the 1769 transit of Venus. More than a century later, they again participated in attempts to establish a precise value for the astronomical unit through the transits of Venus that occurred in 1874 and 1882. In 1887 Mexican astronomers were invited to join efforts to develop a multinational initiative known as the Carte du Ciel and International Astrographic Project, collaborating with 17 other observatories worldwide. Mexican astronomers obtained support from their Government, and they ordered telescopes from the Irish firm of Sir Howard Grubb and Company. An astrograph was used to photograph stars in Mexico's assigned sky zone (between declinations -10° and -16°) down to a limiting magnitude of 11 for the Astrographic Catalogue, and down to magnitude 14 for the Carte du Ciel. The Astrographic Catalogue photography began in February 1900, and the first of the plates for the Carte du Ciel was exposed in 1905. The Mexican astronomers had to overcome a number of serious difficulties, such as the Mexican Revolution of 1910-1920, which caused several delays and the loss of many personnel from the National Astronomical Observatory of Mexico, and then World War I, 1914-1918, which hindered the arrival of the photographic plates and interrupted communication with the Carte du Ciel Commission in Paris. Women usually were employed as 'computers' to measure the Astrographic Catalogue star positions. Between 1921 and 1962, seven volumes were published listing Mexican Astrographic Catalogue star positions. Mexican astronomers finished taking all of the Carte du Ciel plates, except for the -12° declination zone, but because of financial constraints only 375 plates were printed. Afterwards, from 1941, photography of the -13° zone was repeated in order to obtain stellar positions for proper motion studies. In March 1970 the mounting of the historic 33-cm Grubb astrograph and accompanying 25.4-cm guidescope was used at Miahuatlán, Oaxaca, together with a replacement tube assembly and objective to observe a total solar eclipse. Then from 1976 to 1979 three Astronomy students from the National University of Mexico reconstructed and renovated the original Grubb twin-telescope, which is now at Tonantzintla, near Puebla, and is used mainly for educational purposes.

Assessment of growth, survival, and organ tissues of caged mussels (Bivalvia: Unionidae) in a river-scape influenced by coal mining in the southeastern USA

The Clinch River contains one of the most diverse freshwater mussel assemblages in the United States, with 46 extant species, 20 of which are listed as federally endangered. In a 91 km section of the Clinch River, mussel densities have severely declined at key sites from 1979 to 2014 (zone of decline), compared to other river sections that support high density and stable mussel populations (zone of stability). Coal mining has occurred in tributary watersheds that drain to the zone of decline since the late nineteenth century. To determine differences in survival, growth, and organ (gills, digestive glands, kidneys, and gonads) tissue health between the river zones, laboratory-propagated mussels were deployed to cages for one year at four sites each within the zones of mussel stability and decline. Means of growth and survival of mussels in the zone of stability were significantly greater than in the zone of decline, and mean fractions of kidney lipofuscin in mussels in the zone of decline was significantly greater than in the zone of stability. Water concentrations of K+, Na+, Al, and Mn were significantly greater in the zone of decline than in the zone of stability. Statistical correlation results indicated that mussel survival was positively associated with concentrations of Mn in water, and kidney lipofuscin was negatively associated with concentrations of dissolved K+, SO42−, and Mg2+. Most concentrations of contaminants were below published benchmark criteria, yet our results suggest that conditions continue to exist in the zone of decline that promote impacts to mussels that are at least partially associated with low concentration coal-related contaminants. More research is needed to determine the additive, synergistic, or antagonistic effects of these complex ionic mixtures on freshwater mussels from river environments, such as in the Clinch River, where constituent concentrations are relatively low.

CATALOGUE OF COORDINATES AND B-MAGNITUDES IN - 20є – +2є ZONE BASED ON THE ULUGH BEG ASTRONOMICAL INSTITUTE PART OF THE FON PROJECT

Catalogue of 13.4 million stars down to 17.5m was obtained in 2017 by using plates from the Kitab Observatory of Ulugh Beg Astronomical Institute (UBAI) of the Uzbek Academy of Sciences. Kitab's part of Photographic Sky Survey (Russian abbreviation is FON, in next contexts) project include more than 2600 photographic plates, exposed on the Double Astrograph of Zeiss (DAZ, D/F = 40/300, 69/mm) from 1981 to 1996. Digitizationof these plates was made by using Epson Expression 10000XL scanner with the 1200 dpi resolution. Catalogue includes objects from the 1963 plates in declination zone between -20° and +2° for middle epoch 1984.97. The equatorial coordinates of objects were determined in the Tycho-2 reference system and the B-magnitudes in the system of the photoelectric standards. Five participants from Uzbekistan, Germany and Ukraine have taken part in the processing of the digitized images. The average internal accuracy of the catalogue for one observation are 0.23 and 0.15m for the equatorial coordinates and B-magnitudes respectively. For the stars brighter than 14m the errors are 0.09 and 0.05m respectively. The analysis of the catalogue and its comparison with the several astrometric catalogues was done.

Results of astrometric observations of stars with large proper motions using telescopes of the Research Institute of Nikolaev Astronomical Observatory

Astrometric CCD observations of stars with large proper motions were carried out during 2008–2014 using telescopes of the Nikolaev Astronomical Observatory. A catalog of positions and proper motion of 1596 fast stars with proper motions exceeding 150 mas/yr has been compiled based on observation results. The catalog covers the declination zone from 0° to 65°. The standard error of derived proper motion is 1…10 mas/yr for both coordinates depending on the observational history of the star. Data from eight different star catalogs and surveys have been used to derive proper motion. The comparison results of proper motion with data from modern catalogs and results of the statistical test for the detection of possible invisible components are given.

FAINT UBVRI STANDARD STAR FIELDS AT +50° DECLINATION

ABSTRACT Precise and accurate CCD-based UBVRI photometry is presented for ∼2000 stars distributed around the sky in a declination zone centered approximately at +50°. Their photometry has been calibrated to the standard Johnson UBV and Kron–Cousins RI systems through observations of the UBVRI standard stars presented in the various works of Landolt. The magnitude and color range for these stars are 12 ≲ V ≲ 22 and −0.3 ≲ (B − V) ≲ 1.8, respectively. Each star averages 13 measures in each UBVRI filter from data taken on 41 different photometric nights obtained over a 21 month period. Hence, there now exists a network of faint UBVRI photometric standard stars centered on the declination zones δ = −50°, 0°, and +50°.

Assessing toxicity of contaminants in riverine suspended sediments to freshwater mussels.

The Clinch River in Virginia and Tennessee, USA, is well known for its diverse native freshwater mussel assemblages; however, notable declines in mussel populations in recent decades have prompted much concern and subsequent research. The authors examined the toxicity of recently deposited sediments on juveniles of the freshwater mussel Epioblasma brevidens by collecting time-integrated sediment samples from the water column with sediment traps from 11 sites in the Clinch River basin, including 6 sites within an 88-km reach deemed a "mussel zone of decline." Mussels were exposed to the riverine sediments and to 3 control sediments for 28 d; survival, shell length, and biomass were then assessed. Sediment treatment (i.e., river location) had a significant effect on mussel survival (p < 0.01) and biomass (p = 0.02) but did not affect length (p = 0.37), and sediments from 2 of the tributaries were the most toxic. Inorganic and organic analyses of sediments indicated the presence of metals and polycyclic aromatic hydrocarbons at all sites. Manganese was negatively correlated with mussel survival and biomass, as was ammonia with survival and total organic carbon with biomass. Current land uses in the watershed indicate that fossil fuel mining and agriculture may be associated with elevated manganese and ammonia, respectively. The authors found that sediments collected with sediment traps over relatively short deployment durations can help elucidate recent contaminant influx and its potential for inducing toxicity in benthic organisms. Environ Toxicol Chem 2017;36:395-407. © 2016 SETAC.

Astrometric catalogue of stars in the KMAC3 equatorial zone

The catalogue of positions and stellar V magnitudes of up to 17m stars in the declination zone from 2° to 5.5° has been compiled. The catalogue includes 2.05 × 106 stars and is based on the observations performed in 2010–2015 on the meridian axial circle (MAC) of GAO NAN Ukraine and the Astronomical Observatory of Taras Shevchenko National University. The errors of the positions and photometry for stars of 11–14 magnitude are 0.06″–0.08″ and 0.04m–0.08m, respectively.

Astrometric catalogue of stars in the equatorial zone KMAC2

A catalogue of positions and V magnitudes of stars down to 17m in the declination zone from 0 to +2° is compiled. The catalogue contains 1.09 × 106 stars and is based on observations obtained at the meridian axial circle of the Main Astronomical Observatory, National Academy of Sciences of Ukraine and Astronomical Observatory of Kyiv National University in 2001–2005. The accuracy of positions and photometry is 0.05–0.07′′ and 0.05–0.08m, respectively, for stars of 11–14m.

DETERMINATION OF PROPER MOTIONS OF CIRCUMPOLAR STARS BY USING IMAGES FROM UKRVO PLATE ARCHIVES

UkrVO plate archives contain information obtained at different time periods and in different observatories for the same regions of the sky [3, 5, 6, 7, 8]. It allows us to carry out joint processing of plates and to receive new results for interesting objects. To obtain proper motions of stars in circumpolar areas, we selected 34 photographic plates from the RI NAO archive and 161 plates from the archive of the MAO NAS. A mean epoch difference between the plates from these archives is 55 years. Scanning of the plates and data processing were independently carried out by both observatories. A catalog of equatorial positions for 195 thousand stars up to 15m was compiled in the RI NAO (black dots in Fig. 1). A catalog of equatorial positions for 1050 thousand stars up to 16.5m was compiled in MAO (gray dots in Fig. 1). A comparison of positions for common stars contained in these catalogs was conducted. A catalog of proper motions for 30 thousand common stars up to 15m was compiled using these two input catalogs. The obtained result suggests the advisability of processing of all observations to receive proper motions of stars up to 14-15m in the declination zone of 65° to 90°.

Application of vector spherical harmonics for kinematic analysis of stars from zonal catalogues

We solve the problem on a kinematic analysis of the three-dimensional velocity field of stars from zonal catalogues, i.e., catalogues in which the stars are presented at all right ascensions in some declination zones. We have constructed a system of vector spherical harmonics with the properties of completeness and orthogonality for a chosen declination zone. We suggest a method that allows the Ogorodnikov-Milne model parameters in the Galactic coordinate system to be estimated by analyzing the proper motions and radial velocities of stars in the equatorial coordinate system. The vector spherical harmonics are shown to have the following advantages over the standard approach based on a direct leastsquares estimation of the parameters for a specific model. First, in contrast to the standard approach, the new method can reveal all systematic components of the velocity field irrespective of a particular model. Second, it allows one to get rid of the correlation between the sought-for parameters, which presents a serious problem for the conventional method in the case of zonal catalogues. Third, the method of vector spherical harmonics allows the kinematic parameters to be estimated at least by two techniques. Comparison of these two solutions makes it possible to test the standard kinematic model for compatibility with the observational data. The developed method has been tested on the basis of numerical experiments and applied for a kinematic analysis of the proper motions of Tycho-2 stars in the southern hemisphere for which the parallaxes can be estimated using data from the Tycho-2 Spectral Type Catalogue.

Scanning results of images of the 60th declination zone of the FON project. Measurement reduction methods and characterization of the output catalog

A Microtek ScanMaker 9800XL TMA was used to scan 102 plates of 60° declination zone of the northern sky. The images were obtained within the scope of the FON project using the double wide-angle astrograph of the Main Astronomical Observatory (National Academy of Sciences of Ukraine). The procedure is described of processing these scans and compilation of the catalog of equatorial coordinates and brightness. Mean square errors of positions and B-magnitudes of 1 108 603 stars of the output catalog (in the range from 56 to 64° in declination and from 0 to 24 h in right ascension) largely depend on the position on the plate, multiplicity of overlapping, and stellar magnitude. The standard deviations are 0.10–0.32″ for coordinates and 0.04–16 m for stellar magnitudes. The average values of mean square deviations of data of the obtained catalog from data of PPMX and UCAC catalogs are 0.23″ and 0.18 m .

UCAC3: ASTROMETRIC REDUCTIONS

Presented here are the details of the astrometric reductions from the x,y data to mean Right Ascension (RA), Declination (Dec) coordinates of the third U.S. Naval Observatory (USNO) CCD Astrograph Catalog (UCAC3). For these new reductions we used over 216,000 CCD exposures. The Two-Micron All-Sky Survey (2MASS) data are extensively used to probe for coordinate and coma-like systematic errors in UCAC data mainly caused by the poor charge transfer efficiency (CTE) of the 4K CCD. Errors up to about 200 mas have been corrected using complex look-up tables handling multiple dependencies derived from the residuals. Similarly, field distortions and sub-pixel phase errors have also been evaluated using the residuals with respect to 2MASS. The overall magnitude equation is derived from UCAC calibration field observations alone, independent of external catalogs. Systematic errors of positions at UCAC observing epoch as presented in UCAC3 are better corrected than in the previous catalogs for most stars. The Tycho-2 catalog is used to obtain final positions on the International Celestial Reference Frame (ICRF). Residuals of the Tycho-2 reference stars show a small magnitude equation (depending on declination zone) that might be inherent in the Tycho-2 catalog.

A Deep Proper-Motion Survey in Kapteyn Selected Areas. I. Survey Description and First Results for Stars in the Tidal Tail of Sagittarius and in the Monoceros Ring

We describe a high-precision, deep (to V ~ 19-21), absolute proper-motion survey that samples ~50 lines of sight in the Kapteyn selected areas along declination zones -15°, 0°, and 15°. In many fields the astrometric baseline reaches nearly a century. We demonstrate that these data provide typical per star precisions between ~1 and 3 mas yr^(-1) to the above magnitude limits, with the absolute reference frame established by numerous extragalactic sources in each survey field. Combined with existing and ongoing photometric and radial velocity surveys in these fields, these astrometric data will enable, among other things, accurate detailed dynamical modeling of satellite interactions with our Galaxy. In this contribution we describe the astrometric part of our survey and show preliminary results along the trailing tail of the Sagittarius dwarf galaxy, and in the Monoceros Ring region.

The CdC2000 BordeauxCarte du Cielcatalogue ($\mathsf{+11\degr \leq \delta \leq +18\degr}$)

Context. This work is part of a program of proper motion measurements in the Bordeaux Carte du Ciel zone. Aims. We present the CdC2000 catalogue issued from the reduction of the complete Bordeaux Carte du Ciel zone observed at the begining of last century with the Bordeaux astrograph. Methods. Plates have been individually reduced using the TYCHO-2 Catalogue as the astrometric reference. Results. This catalogue is a positional catalogue of 344 781 stars covering the declination zone +11 +18 . The average epoch of positions is 1914.7. The data are from the 512 Carte du Ciel plates archived at the Bordeaux Observatory and scanned with the APM Cambridge automatic measuring machine.Astrometric standard errors are about 0.10 00 to 0.12 00 on positions and 0.6 magnitudes on photographic magnitudes. Conclusions.A detailed study of errors and a comparison of various reduction methods are presented in order to take into account the significant propagated errors from the reference catalogue. The CdC2000 provides positions at the epoch of the plates for 50 682 TYCHO-2 stars. The associated positions are proved to be p 2 more precise than the positions given by the TYCHO-2 catalogue at the epoch of the plates (0.11 00 instead of 0.15 00 ). This work is part of a program of proper motion measurements in the Bordeaux Carte du Ciel zone.

The PM2000 Bordeaux proper motion catalogue ($\mathsf{+11\degr \leq \delta \leq +18\degr}$)

We present a proper motion catalogue of 2 670 974 stars, covering the declination zone $+11\degr \leq \delta \leq +18 \degr$. Proper motions were derived from the comparison of the positional M2000 catalogue (systematic observations of the Bordeaux Carte du Ciel Zone with the meridian circle, completed in 2000) with positions derived from the reduction of 512 Carte du Ciel plates of the Bordeaux zone (scanned at the APM Cambridge), the AC2000.2 catalogue, the USNO-A2.0 catalogue and the unpublished Yellow Sky (YS3) USNO catalogue. The catalogue has a limiting magnitude $V_{M}=16.2$ (Bordeaux CCD meridian circle magnitude) and is complete down to $V_{M}=15.4$. Depending on magnitude, the positional precision at mean epoch ranges from 50 to 70 mas and the precision of proper motions varies from 1.5 mas/yr to 6 mas/yr. Meridian V M magnitudes are provided for all objects together with additional photometry from the 2MASS catalogue when available (99.5% of objects). Positions and proper motions are on the ICRS (International Celestial Reference System). Systematic offsets in 2MASS positions and in UCAC2 proper motions were revealed from comparisons with PM2000.

The Kyiv Meridian Axial Circle catalogue of stars in fields with extragalactic radio sources

A catalogue of astrometric (positions, proper motions) and photometric ( B , V , R , r' , J ) data of stars in fields with ICRF objects has been compiled at the Observatory of the National Academy of Sciences of Ukraine and the Kyiv University Observatory. All fields are located in the declination zone from 0° to +30°; the nominal field size is 46 ' (right ascension$)\times 24'$ (declination). The observational basis of this work is 1100 CCD scans down to $V=17$ mag which were obtained with the Kyiv meridian axial circle in 2001–2003. The catalogue is presented in two versions. The version KMAC1-T contains 159 fields (104 796 stars) and was obtained with reduction to the Tycho2 catalogue. For another 33 fields, due to a low sky density of Tycho2 stars, the reduction was found to be unreliable. Transformation to the ICRF system in the second version of the catalogue (KMAC1-CU) was performed using the UCAC2 and CMC13 catalogues as a reference; it contains 115 032 stars in 192 fields and is of slightly better accuracy. The external accuracy of one catalogue position is about 50–90 mas for $V<15$ mag stars. The average error of photometry is better than 0.1 mag for stars down to 16 mag.

The on-ranch economics of riparian zone cattle grazing management.

A simulation model of a cattle ranch based in southern Alberta, Canada was developed to evaluate the on-ranch economics of adopting different grazing management strategies to improve riparian grazing capacity in natural grass rangeland. Under low-cost scenarios, there are positive economic incentives to adopt strategies to maintain riparian zones that already have high grazing capacity. However, riparian zones that have declined to moderate or low grazing capacity may require additional economic incentives to encourage ranches to adopt more costly management strategies to improve the grazing capacity. The economic incentives to adopt costly management strategies are highly sensitive to the size and shape of the riparian zone and rates of grazing capacity decline or improvement.

The Pul-3 catalogue of 58483 stars in the Tycho-2 system

A catalogue of positions and proper motions of 58483 stars (Pul-3) has been constructed at the Pulkovo observatory. The Pul-3 is based on the results of measurements of photographic plates with galaxies (Deutsch's plan). All plates were taken using the Pulkovo Normal Astrograph (the first epoch is in the 1950s and the second epoch is in the 1970s). The Pul-3 catalogue contains stars of mainly 12 to 16.5 mag in 146 fields with galaxies in the declination zone from -5° to +85°. The Tycho-2 has been used as a reference catalogue. The mean epoch of the Pul-3 is 1963.25. The internal positional accuracy of the Pul-3 catalogue at the mean epoch of observations is ±80 mas. The accuracy of the proper motions is mostly within ±3 mas/yr to ±12 mas/yr. Comparisons of the Pul-3 with Tycho-2 and ARIHIP have been done at the mean epoch of the Pul-3. The Pul-3 external positional accuracy relative to Tycho-2 is ±150 mas.

Support of Science-Based Decisions Concerning the Evaluation of the Toxicology of Mixtures: A New Beginning

The Clinch River contains one of the most diverse freshwater mussel assemblages in the United States, with 46 extant species, 20 of which are listed as federally endangered. In a 91 km section of the Clinch River, mussel densities have severely declined at key sites from 1979 to 2014 (zone of decline), compared to other river sections that support high density and stable mussel populations (zone of stability). Coal mining has occurred in tributary watersheds that drain to the zone of decline since the late nineteenth century. To determine differences in survival, growth, and organ (gills, digestive glands, kidneys, and gonads) tissue health between the river zones, laboratory-propagated mussels were deployed to cages for one year at four sites each within the zones of mussel stability and decline. Means of growth and survival of mussels in the zone of stability were significantly greater than in the zone of decline, and mean fractions of kidney lipofuscin in mussels in the zone of decline was significantly greater than in the zone of stability. Water concentrations of K+, Na+, Al, and Mn were significantly greater in the zone of decline than in the zone of stability. Statistical correlation results indicated that mussel survival was positively associated with concentrations of Mn in water, and kidney lipofuscin was negatively associated with concentrations of dissolved K+, SO42−, and Mg2+. Most concentrations of contaminants were below published benchmark criteria, yet our results suggest that conditions continue to exist in the zone of decline that promote impacts to mussels that are at least partially associated with low concentration coal-related contaminants. More research is needed to determine the additive, synergistic, or antagonistic effects of these complex ionic mixtures on freshwater mussels from river environments, such as in the Clinch River, where constituent concentrations are relatively low.