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1.
《Limnologica》2015
The freshwater pearl mussel (Margaritifera margaritifera) is a highly specialized and sensitive freshwater bivalve, whose survival in the juvenile phase is indicative of high quality habitats. This contribution investigates the use of juvenile freshwater pearl mussels as bioindicators, considering the influence of mussel stock and study stream conditions on juvenile performance, as described by survival and growth rates. A standardized cross experiment was carried out investigating juvenile performance in four different pearl mussel stocks originating from the Rhine, Danube and Elbe drainages, representing distinct genetic conservation units. The juveniles were exposed in five study streams which were selected to integrate pearl mussel streams with different water qualities and recruitment status of the mussel population. Per study stream, five standard mesh cages containing an equal number of 20 (10 × 2) juvenile pearl mussels per stock in separate chambers were installed. Survival and growth rates of juveniles were checked after three months (i.e. before their first winter) and after nine months (i.e. after their first winter). Mussel stock and study stream conditions significantly influenced juvenile performance. Growth rates were determined by study stream conditions and increased with stream water temperature, organic carbon and C/N ratios. Survival rates varied stock-specifically, indicating different levels of local adaptation to their native streams. Due to the detection of stream-specific differences in juvenile performance, freshwater pearl mussels appear suitable as bioindicators. However, a careful consideration of stock-specificity is necessary to avoid false interpretation of bioindication results. The comparison of stock-specific survival in native versus non-native streams implicates that exposure of juveniles outside their native habitats is able to increase breeding success or else serve for risk spreading in breeding programs. 相似文献
2.
Yasuo Miyabuchi Shin-ichiro Ikebe Kazunori Watanabe 《Journal of Volcanology and Geothermal Research》2008
The active crater of Nakadake at Aso Volcano, southwestern Japan, has been occupied by a lake during its dormant periods. Multiple ash emissions were observed from the crater lake between July 2003 and August 2005. The largest events occurred on 10 July 2003 and 14 January 2004. On 10 July 2003, ash (41 tons) was dispersed throughout an area extending 14 km east-northeast of the vent, and on 14 January 2004 ash (32 tons) extended 8 km to the east-southeast. Thereafter, small ash emissions were frequent at the crater lake, in which the water level fell considerably from April to August 2005. During this period major ash emitting events, producing mostly white aggregated ash, occurred on June 10–12, June 21 (4.2 tons) and July 25 (1.2 tons). Ash emissions at the Nakadake crater in 2003–2005 were classified into three types: gentle release of white aggregated ash from fumaroles inside the crater lake (e.g. daytime of 14 April, 10–12 June and 25 July 2005); emission of black ash from an almost dried-up vent (21 June 2005); and short-time (ca. 20 s) small-explosion-triggered gas-and-ash emission through the crater lake (10 July 2003, 14 January 2004 and 14 April 20h41m 2005). All products from these ash emissions consisted of fine-grained (< 1 mm) glass shards, crystals and lithic fragments, and contained neither lapilli nor blocks. Although the glass shards show varying degrees of crystallization and alteration, clear glass shards, which appear fresh, are probably juvenile materials. These observations suggest that the 2003–2005 ash emissions from the crater lake of Nakadake Volcano are related to newly ascending magma. 相似文献
3.
Nutrient enrichment from shrimp aquaculture poses an increasing environmental threat due to the industry's projected rapid growth and unsustainable management practices. Traditional methods to monitor impacts emphasize water quality sampling; however, there are many advantages to bioindicators, especially in developing countries. We investigated the usefulness of three bioindicators -- growth, tissue nitrogen content and nitrogen stable isotope signature (delta(15)N) -- in the tropical red macroalga Acanthophora spicifera. Algae were collected, cultured, and deployed in a spatial array around the outflow from a shrimp farm in Moorea, French Polynesia, to detect nitrogenous wastes. All three parameters were highest adjacent to the shrimp farm indicating nutrient enrichment, and delta(15)N values confirmed the shrimp farm as the dominant nutrient source (5.63-5.96 per thousand). Isotope ratios proved the most sensitive indicator, as delta(15)N signatures were detected at the most distant sites tested, confirming their usefulness in tracing nutrients and mapping the spatial extent of enrichment. 相似文献
4.
S. Caliro G. Chiodini G. Izzo C. Minopoli A. Signorini R. Avino D. Granieri 《Journal of Volcanology and Geothermal Research》2008
Lake Averno is situated in the homonymous crater in the northwestern sector of the Campi Flegrei active volcanic system in Campania region, Italy. In February 2005 a fish kill event was observed in the lake, prompting a geochemical survey to ascertain the possible cause. In February 2005 a geochemical survey revealed that the lake water was unstratified chemically and isotopically, presumably, as a result of lake overturn. This fish kill phenomenon was recorded at least two other times in the past. In contrast to the February 2005 results, data collected in October 2005, shows the Lake Averno to be stratified, with an oxic epilimnion (surface to 6 m) and an anoxic hypolimnion (6 m to lake bottom at about 33 m). 相似文献
5.
Summary The paper describes the seismic activity of the Jílovice fault and the last earthquake of Aug. 10, 1987.
Резюме Оnuсывaеmся сеŭсмuческaя aкmuвносmь рaзломa йuловuце в северовосmочноŭ Чехuu u землеmрясенuе с 10-о о aв усma 1987 , очa коmоро о был связaн с ?rt;aнным разломом.相似文献
6.
Analysis of changes in the vertical distribution of tritium in the Caspian Sea water mass in 1994–1996 led to a conclusion that the sea level fall that started in 1996 was accompanied by a rearrangement of the water mass steady hydrological structure characteristic of the high sea-level stand.__________Translated from Vodnye Resursy, Vol. 32, No. 4, 2005, pp. 406–409.Original Russian Text Copyright © 2005 by Brezgunov, Ferronskii. 相似文献
7.
Stable nitrogen isotopes (δ15N) in bioindicators are increasingly employed to identify nitrogen sources in many ecosystems and biological characteristics of the eastern oyster (Crassostrea virginica) make it an appropriate species for this purpose. To assess nitrogen isotopic fractionation associated with assimilation and baseline variations in oyster mantle, gill, and muscle tissue δ15N, manipulative fieldwork in Chesapeake Bay and corresponding modeling exercises were conducted. This study (1) determined that five individuals represented an optimal sample size; (2) verified that δ15N in oysters from two locations converged after shared deployment to a new location reflecting a change in nitrogen sources; (3) identified required exposure time and temporal integration (four months for muscle, two to three months for gill and mantle); and (4) demonstrated seasonal δ15N increases in seston (summer) and oysters (winter). As bioindicators, oysters can be deployed for spatial interpolation of nitrogen sources, even in areas lacking extant populations. 相似文献
8.
Vyacheslav M. Zobin Juan José Ramírez Hydyn Santiago Eliseo Alatorre Carlos Navarro 《Bulletin of Volcanology》2011,73(1):91-99
Continuous tilt changes during the 2004–2005 effusive-explosive episodes at Volcán de Colima (México) were recorded simultaneously
by two tiltmeters installed on opposite sides of the volcano at elevations of 2200 m and 3060 m above sea level. Data indicate
that the 2004 lava extrusion was preceded by an inflation accompanied by a deflation. The 2005 explosion sequences were associated
with a deflationary–inflationary tilt. The period between the 2004 extrusion and the 2005 explosions was characterized by
an inflationary tilt during a 3 month period. Two deformation sources were located. The first was situated at a depth between
300 m and 1800 m beneath the crater at the northern flank of the volcano and was responsible for volcano deformation during
the preliminary September 2004 stage, the October 2004 extrusion, and the initial stage of the transition period and the March
2005 explosion sequence. The second source was located at a depth between 1800 m and 2800 m beneath the crater at the southern
flank of the volcano and was responsible for volcano deformation during the final stage of the transition period and the May–June
2005 explosion sequence. 相似文献
9.
《Limnologica》2016
The ecological integrity of freshwater ecosystems is regularly examined through assessment of their macroinvertebrate assemblages. The various methods used in such biomonitoring all have one characteristic in common – the neglect of water mites. Even though this group perfectly fulfills all necessary requisites for successful bioindicators, these invertebrates are either completely ignored or lumped together as “Acari”.This study, for the first time, uses water mites (Hydrachnidia) as bioindicators in the Neotropics to compare the anthropogenic stress in 15 streams at three different levels of contamination (pristine, rural, urban). In total, 4371 water mite specimens, belonging to 31 genera and 14 families, were collected.Diversity, abundance, and richness of water mite assemblages were significantly reduced with increasing levels of contamination. These differences were clearest in the dry season. Atractidella turned out to be, by far, the most tolerant water mite genus, having the greatest abundance at the most contaminated sites. In contrast, Pseudotorrenticola was found only in pristine waters, while Hydrodroma, Limnesia, Koenikea, Torrenticola, Monatractides and the family Aturidae showed clear preferences for pristine waters.Our data show, that water mites, identified to genus level, are well suited for water quality assessment in neotropical lowland streams, clearly distinguishing different levels of contamination/anthropogenic stress. 相似文献
10.
Al-Rousan SA Al-Shloul RN Al-Horani FA Abu-Hilal AH 《Marine pollution bulletin》2007,54(12):1912-1922
In order to assess pollutants and impact of environmental changes in the coastal region of the Jordanian Gulf of Aqaba, concentrations of six metals were traced through variations in 5 years growth bands sections of recent Porties coral skeleton. X-radiography showed annual growth band patterns extending back to the year 1925. Baseline metal concentrations in Porites corals were established using 35 years-long metal record from late Holocene coral (deposited in pristine environment) and coral from reef that is least exposed to pollution in the marine reserve in the Gulf of Aqaba. The skeleton samples of the collected corals were acid digested and analyzed for their Cd, Cu, Fe, Mn, Pb and Zn content using Flame Atomic Absorption Spectrophotometer (FAAS). All metal profiles (except Fe and Zn) recorded the same metal signature from recent coral (1925–2005) in which low steady baseline levels were displayed in growth bands older than 1965, similar to those obtained from fossil and unpolluted corals. Most metals showed dramatic increase (ranging from 17% to 300%) in growth band sections younger than 1965 suggesting an extensive contamination of the coastal area since the mid sixties. This date represents the beginning of a period that witnessed increasing coastal activities, constructions and urbanization. This has produced a significant reduction in coral skeletal extension rates. Results from this study strongly suggest that Porites corals have a high tendency to accumulate heavy metals in their skeletons and therefore can serve as proxy tools to monitor and record environmental pollution (bioindicators) in the Gulf of Aqaba. 相似文献
11.
E. N. Dolgopolova 《Water Resources》2005,32(1):43-49
Energy balance of an ice-covered flow in a constant-slope reach of a regulated river is considered. The ratio of energy losses for viscous friction to the total flow energy is evaluated. The turbulence intensities of an open and ice-covered flows are compared.Translated from Vodnye Resursy, Vol. 32, No. 1, 2005, pp. 48–54.Original Russian Text Copyright © 2005 by Dolgopolova. 相似文献
12.
Summary We find no effect of the interplanetary magnetic field(IMF) sector boundary crossing in ozone at altitudes ranging from the middle stratosphere(10 hPa) to the lower mesosphere(0.4 hPa) at middle latitudes(40°–60° N), based on winter data over the period of December 1979–December 1982.
Резюме Мы не нaшлu нuкaко о эффекma nересеченuя секmорноŭ рaнuцы межnлaнеmно о мa нumно о nоля в озоне в облaсmu высоm меж?rt;у сре?rt;неŭ сmрamосфероŭ(10 Пa) u нuжнеŭ мезосфероŭ(0,4 Пa) нa сре?rt;нuх шuроmaх(40°–60° с.ш.), nрuменяя зuмнuе ?rt;aнные зa nерuо?rt; ?rt;екaбрь 1979 – ?rt;екaбрь 1982 .相似文献
13.
Summary Constraints to the density distribution within the Earth providing the measured Stokes' parameters of the external gravity
field are derived. Formulas describing the internal gravity field of this density distribution are established. Expansions
of all used quantities (gravity field, density, topography of the Earth's surface) by means of spherical harmonic series have
been applied and the results are given in the form of series, in which the magnitude of the term corresponds to a certain
power of the Earth's flattening.
Резюме Выве?rt;ены связu ?rt;ля рaсnре?rt;еленuя nлоmносmu в Земле, коmорое у?rt;овлеmворяеm зa?rt;aнным nосmоянным Сmоксa внешне о рaвumaцuонно о nоля. Нaŭ?rt;ены формулы, оnuсывaющuе внуmреннее рaвumaцuонное nоле эmо о рaсnре?rt;еленuя. Исnользовaно рaзложенuе рaвumaцuонно о nоля, nлоmносmu u mоnо рaфuu в ря?rt; nо сферuческuм функцuям. Резульmamы nре?rt;сmaвлены в вu?rt;е ря?rt;a, оm?rt;ельные члены коmоро о nроnорцuонaльны сmеnеням сжamuя Землu.相似文献
14.
Results of field observations and numerical modeling of hydrogen sulfide pollution of the Sea of Azov in 2001 are presented.Translated from Vodnye Resursy, Vol. 32, No. 2, 2005, pp. 171–183.Original Russian Text Copyright © 2005 by Debolskaya, Yakushev, Sukhinov. 相似文献
15.
Two main groups of methods used for comprehensive evaluation of continental surface water quality are analyzed. A new method of comprehensive evaluation of the degree of continental surface water contamination, developed by the authors of this paper based on a combination of the differentiated and comprehensive approaches, is described in detail.Translated from Vodnye Resursy, Vol. 32, No. 1, 2005, pp. 61–69.Original Russian Text Copyright © 2005 by Nikanorov, Yemelyanova. 相似文献
16.
17.
The general picture of wetting the East European Plain in 1966–1985 is established by studying the trajectories of more than 5000 cyclones in the Northern Hemisphere. The role of the Arctic High as a regulator of the paths of the Atlantic cyclones is established. It is shown that the majority of rivers of the East European Plain feature higher rate of streamflow in the years with the El Nino effect.Translated from Vodnye Resursy, Vol. 32, No. 1, 2005, pp. 108–114.Original Russian Text Copyright © 2005 by Babkin, Klige. 相似文献
18.
Comparative analysis is applied to different management methods (compulsion, inducement, persuasion) in two- or three-level dynamic hierarchic models of river water quality in the cases of point sources of pollutants. Conclusions regarding the effect of additional control levels on the behavior of the hierarchic system are made.__________Translated from Vodnye Resursy, Vol. 32, No. 4, 2005, pp. 504–511.Original Russian Text Copyright © 2005 by Ugol’nitskii, Usov. 相似文献
19.
Regularities of bacteria distribution in the bottom sediments of the Upper Volga reservoirs are studied. Human-induced changes in the structure and activity of bacteriobenthos communities occurring in water body areas adjacent to towns and settlements are described. Reservoir zones subject to long-term human impact are distinguished.__________Translated from Vodnye Resursy, Vol. 32, No. 4, 2005, pp. 489–499.Original Russian Text Copyright © 2005 by Kosolapov, Krylova, Kopylov. 相似文献
20.
A. N. Dzyuban 《Water Resources》2005,32(1):65-72
The results of integrated microbiological studies of the Sheksna Reservoir are presented. The environmental conditions of its water and soil, which are exposed to diverse anthropogenic impact, are assessed. Parts of the reservoir with persistent anthropogenic pollution, which are environmentally unfavorable in terms of the state of silt microflora, are recognized.Translated from Vodnye Resursy, Vol. 32, No. 1, 2005, pp. 70–78.Original Russian Text Copyright © 2005 by Dzyuban. 相似文献