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1
Morales, Maria C., e Jaime Meruane. "The northern river shrimp Cryphiops caementarius (Decapoda, Palaemonidae). Research chronology between 1958 and 2008, I: distribution, population status, biology and life cycle". Crustaceana 86, n. 12 (2013): 1441–51. http://dx.doi.org/10.1163/15685403-00003259.
Testo completoAbstract (sommario):
The present study is a review of the main inland water malacostracan species of northern Chile: Cryphiops caementarius (Molina, 1782). This species sustains the local fisheries in northern and central Chilean hydrographical basins. Cryphiops caementarius, in Chile known as the northern river shrimp, is endemic to rivers west of the Andes Mountains in Peru, and south from Chancay-Lambayeque River and the rivers in the northern Chilean littoral up to 32°55′S. Research on this species in its natural habitat consigned between 1958 to 2008 was directed to population knowledge, including mainly the existing populations in rivers in the Regions of Atacama and Coquimbo. Important advances were also made with regards to the study of the embryonic development, biology, life cycle and reproduction that serve as a basis for the technological development of juvenile production in a controlled environment.
2
Philippsen, Bente, e Jan Heinemeier. "Freshwater Reservoir Effect Variability in Northern Germany". Radiocarbon 55, n. 3 (2013): 1085–101. http://dx.doi.org/10.1017/s0033822200048001.
Testo completoAbstract (sommario):
The freshwater reservoir effect is a potential problem when radiocarbon dating fish bones, shells, human bones, or food crusts on pottery from sites near rivers or lakes. The reservoir age in hardwater rivers can be up to several thousand years and may be highly variable. Accurate 14C dating of freshwater-based samples requires knowing the order of magnitude of the reservoir effect and its degree of variability. Measurements on modern riverine materials may not give a single reservoir age correction that can be applied to archaeological samples, but they show the order of magnitude and variability that can also be expected for the past. This knowledge will be applied to the dating of food crusts on pottery from the Mesolithic sites Kayhude at the Alster River and Schlamersdorf at the Trave River, both in Schleswig-Holstein, northern Germany.
3
Ganf, George G., e Naomi Rea. "Potential for algal blooms in tropical rivers of the Northern Territory, Australia". Marine and Freshwater Research 58, n. 4 (2007): 315. http://dx.doi.org/10.1071/mf06161.
Testo completoAbstract (sommario):
Rivers in the Northern Territory (NT) of Australia are under pressure from increasing vegetation clearance, land use and nutrient run-off. The literature on algal blooms clearly identifies the predisposing factors but in the NT, these factors are not well researched. We report on the potential for tropical rivers to experience problems related to algal growth. NT rivers were found to have a low nutrient status and a viable inoculum of blue-green, brown and green algal communities. The growth response of these algal groups to nutrient enrichment via bioassays and pulse-amplitude-modulation (PAM) fluorometry measurements varied among rivers and the addition of N, P or N&P. However, the overwhelming findings were that all rivers had the potential to experience algal blooms with enrichment. Back-calculations based on the chlorophyll concentrations recorded in bioassay experiments and stoichiometric ratios of chlorophyll:nutrients suggest there are pools of biologically available organic forms of N and P in addition to inorganic forms. The role of river length in the development of algal blooms was investigated: the longer the river reach, the slower the flow, and the greater the availability of nutrients, the higher potential for algal blooms. Given the strong indications that increased nutrient run-off to tropical rivers will result in algal blooms, prudent land-use and development with nutrient management strategies is essential.
4
Ulvan, Eva Marita, Anders Foldvik, Arne Johan Jensen, Bengt Finstad, Eva Bonsak Thorstad, Audun Håvard Rikardsen e Tor Fredrik Næsje. "Return migration of adult Atlantic salmon (Salmo salar L.) to northern Norway". ICES Journal of Marine Science 75, n. 2 (18 settembre 2017): 653–61. http://dx.doi.org/10.1093/icesjms/fsx183.
Testo completoAbstract (sommario):
Abstract The return migration of adult Atlantic salmon was investigated by analysing recaptures of individuals tagged and released as smolts in the River Altaelva and the River Halselva using a catch per unit effort approach. Although the salmon were recaptured over a large area along the coastline (from >1100 km south to > 500 km northeast of their home rivers), the results indicated a relatively accurate homeward navigation for most individuals. The straying rate to rivers other than the home river was 9%. Multi-sea-winter salmon returned earlier in the season than one-sea-winter salmon, but the geographical distribution of recaptures did not differ. Recaptures were equally distributed north and south of the home rivers, implying that salmon were arriving to the coast both north and south of their home rivers and that they may have returned from different ocean areas. This was supported by the fact that several salmon were recaptured in both the southern and northern parts of the North Atlantic Ocean, including at the Faroes, south coast of Greenland, Svalbard and in the Barents Sea. This study supports the hypothesis that the coastal phase of the natal homing in migrating fish species is neither passive nor guided by currents alone.
5
Lehnhoff, Erik A., Fabian D. Menalled e Lisa J. Rew. "Tamarisk (Tamarixspp.) Establishment in its Most Northern Range". Invasive Plant Science and Management 4, n. 1 (marzo 2011): 58–65. http://dx.doi.org/10.1614/ipsm-d-10-00036.1.
Testo completoAbstract (sommario):
AbstractTamarisk, a shrub or small tree native to Eurasia, was introduced to North America in the early 1800s and is now naturalized throughout many riparian areas of the southwestern United States, where extensive research has been conducted. It is a more recent invader to the northern Great Plains, and fewer studies have been conducted on tamarisk ecology and management in this area. The objectives of this research were to investigate the overwintering potential of tamarisk seeds in Montana and the relationship between hydrologic conditions and historic tamarisk establishment. Emergence of seedlings from seeds stored for different time periods at a range of temperatures was evaluated in a greenhouse study. Emergence rates declined after a 7-d storage period, but storage time had no effect on subsequent emergence rates, and seeds stored at −14 C and 5 C had greater emergence rates than those stored at 20 C and 35 C. Patterns in tamarisk establishment were assessed through age and hydrologic data collected from a reservoir (Fort Peck), a regulated river (Bighorn), and an unregulated river (Yellowstone) in Montana. These data indicated that tamarisk establishment at the reservoir was closely related to historic water levels, whereas establishment on rivers was not related to flow. However, data from the rivers indicated that recruitment differed between regulated and unregulated rivers, with the regulated river having less recruitment after the period of initial colonization than the unregulated river. Our results show that tamarisk seeds have the ability to overwinter in Montana and can establish under a range of flow conditions, indicating potential recolonization of sites after tamarisk removal.
6
Senay, C., S. Harvey-Lavoie, C. J. Macnaughton, G. Bourque e D. Boisclair. "Morphological differentiation in northern pike (Esox lucius): the influence of environmental conditions and sex on body shape". Canadian Journal of Zoology 95, n. 6 (giugno 2017): 383–91. http://dx.doi.org/10.1139/cjz-2016-0159.
Testo completoAbstract (sommario):
Morphological differentiation may allow individuals to cope with prevailing environmental conditions. Morphological differentiation in fish characterized by sagittiform shape and ambush predator behaviour, such as northern pike (Esox lucius L., 1758), has rarely been addressed. Morphological differentiation was assessed in two rivers exhibiting contrasting flow regimes: a hydropeaking river characterized by large and frequent fluctuations in flow rates and an unregulated river. An increase in northern pike movement rate was observed in the hydropeaking river. Therefore, morphological features enhancing sustained and burst swimming, as well as manoeuvrability, were expected. Our objectives are to (i) compare morphology between the two rivers and (ii) assess morphological differentiation between sexes. Using geometric morphometrics, shape significantly diverged between rivers irrespective of sex and between sexes in the hydropeaking river. Individuals from the hydropeaking river had more elongated heads, deeper bodies and caudal peduncles, and longer dorsal fin insertions than individuals from the unregulated river. Caudal fin differences between rivers were not consistent between sexes. Morphological differentiation suggested a trade-off among adaptations for sustained and burst swimming, as well as manoeuvrability, to cope with variable flows in a hydropeaking river. Morphological differentiation may allow the exploitation of spatially and temporally variable environmental conditions, including those stemming from river flow regulation.
7
Jensen, Arne Johan, e Bjørn Ove Johnsen. "Different Adaptation Strategies of Atlantic Salmon (Salmo salar) Populations to Extreme Climates with Special Reference to some Cold Norwegian Rivers". Canadian Journal of Fisheries and Aquatic Sciences 43, n. 5 (1 maggio 1986): 980–84. http://dx.doi.org/10.1139/f86-120.
Testo completoAbstract (sommario):
Some of the salmon rivers on the western and northern coasts of Norway are very cold, and the sea temperature outside these rivers is almost always higher than that in the river. Growth rates of Atlantic salmon (Salmo salar) parr and smolt ages and sizes have been examined in three such cold rivers. We found indications that the lower temperature limit for growth of Atlantic salmon is not a fixed temperature, but varies from population to population according to the temperature regime of their environment. Smolts are small, with average sizes of 12–13 cm total length. Females dominated in number among the smolts, but the dominance was less pronounced than in most other rivers. Strategies used by Norwegian salmon in cold rivers are therefore different from those employed by salmon in the northern extremes of the salmon's range in Canada.
8
Degerman, Erik, Kjell Leonardsson e Hans Lundqvist. "Coastal migrations, temporary use of neighbouring rivers, and growth of sea trout (Salmo trutta) from nine northern Baltic Sea rivers". ICES Journal of Marine Science 69, n. 6 (1 luglio 2012): 971–80. http://dx.doi.org/10.1093/icesjms/fss073.
Testo completoAbstract (sommario):
Abstract Degerman, E., Leonardsson, K., and Lundqvist, H. 2012. Coastal migrations, temporary use of neighbouring rivers, and growth of Sea trout (Salmo trutta) from nine northern Baltic Sea rivers – ICES Journal of Marine Science, 69: 971–980. The wild migratory trout (Salmo trutta) stocks in the northern Baltic Sea are threatened, and the fishery is thought to play a significant role in the population decline. Therefore, knowledge about the migration patterns of these stocks is needed to develop appropriate management plans. For this reason, we analysed the movement pattern from recaptures of mandatory releases of tagged hatchery-reared trout smolt from nine rivers in the region (1998–2007). The median time from release until recapture was 366 days, and the median migration distance at recapture was 27 km, with a dominating southward direction for northern stocks. Most of the recaptured fish were immature (65%), and recaptures in rivers (55%) dominated over recaptures along the coast (44%). Riverine recaptures were most frequent during autumn–spring. A total of 16% of all recaptures in rivers occurred in non-natal rivers. Straying was about twice as frequent among fish from small rivers as from large rivers. The results from the river Gideälven indicate that using broodstock from other rivers in stocking programmes may lead to a high proportion of strayers. In addition, temporary use of neighbouring rivers was more frequent in large rivers during winter. Growth, in terms of length increment, was high, especially in fish from southern parts of the Baltic, and higher than in neighbouring warmer and more saline sea areas.
9
Bataragoa, Nego Elvis, e Alex D. Kambey. "Species of Fish in rivers in the Northern Peninsula of Sulawesi Island". Jurnal Ilmiah PLATAX 9, n. 1 (22 giugno 2021): 66. http://dx.doi.org/10.35800/jip.9.1.2021.34330.
Testo completoAbstract (sommario):
This study aims to determine the species of fish found in the Poigar River, Ranoyapo River, Maruasey River, Talawaan River, and Likupang River in the northern peninsula of Sulawesi Island. These five rivers empty into the Sulawesi Sea. Sampling was carried out in the upstream, middle and downstream parts of the river, all sampling areas were freshwater areas, estuary areas with brackish water types were not included in this study. Sampling was carried out using cast nets and electric shocks. There are 58 species (16 orders, 21 families, 40 genera). Families Gobidae (9 genera, 19 species) and Eleotridae (8 genera 13 species), 19 other families have only 3 or 2 or 1 species. There are 28 species of Ranoyapo River, 25 species of Maruasey River, 23 species of Poigar River, 15 species of Likupang River, and 9 species of Talawaan River. Eel Anguilla marmorata widely distributed in five rivers, and Eleotris melanosoma (Eleotridae) Osteochilus hasseltii (Cyprinidae) in four rivers. The other species are only found in 3, 2, and 1 rivers. There are 27 species found in only one river.Keywords: Freshwater; River; Species; Fish.AbstrakPenelitian ini bertujuan untuk mengetahui spesies ikan yang terdapat di Sungai Poigar, Sungai Ranoyapo, Sungai Maruasey, Sungai Talawaan dan Sungai Likupang di semenanjung utara Pulau Sulawesi. Lima sungai ini bermuara di Laut Sulawesi. Pengambilan sampel dilakukan pada bagian hulu, tengah dan bagian hilir sungai, seluruh wilayah pengambilan sampel adalah wilayah air tawar, daerah muara dengan tipe air payau tidak termasuk dalam penelitian ini. Pengambilan sampel dilakukan dengan menggunakan jaring lempar dan kejutan listrik. Terdapat 58 spesies (16 ordo, 21 famili, 40 genus). Famili Gobidae (9 genus, 19 spesiies) dan Eleotridae (8 genus 13 spesies), 19 Famili yang lain hanya memiliki 3 atau 2 atau 1 spesies. Sungai Ranoyapo terdapat 28 spesies, Sungai Maruasey 25 spesies, Sungai Poigar 23 spesies, Sungai Likupang 15 spesies dan Sungai Talawaan 9 spesies. Ikan sidat Anguilla marmorata menyebar luas pada lima sungai, dan Eleotris melanosoma (Eleotridae) Osteochilus hasseltii (Cyprinidae) pada empat sungai. Spesies yang lain hanya ditemukan pada 3, 2 dan 1 sungai. Terdapat 27 spesies yang ditemukan hanya pada satu sungai.Keywords: Freshwater; River; Species; Fish.
10
Wrona, Fred J., e William Gummer. "Northern rivers ecosystem initiative: contextual overview". Hydrological Processes 20, n. 19 (2006): 4005–7. http://dx.doi.org/10.1002/hyp.6429.
Testo completo
11
KO, MING-KO, e AONDOVER TARHULE. "Streamflow droughts of northern Nigerian rivers". Hydrological Sciences Journal 39, n. 1 (febbraio 1994): 19–34. http://dx.doi.org/10.1080/02626669409492717.
Testo completo
12
Curtean-Bănăduc, Angela. "Benthic Macroinvertebrate Communities in the Northern Tributaries of the “Iron Gates” Gorge (Danube River)". Transylvanian Review of Systematical and Ecological Research 16, n. 3 (1 dicembre 2014): 151–64. http://dx.doi.org/10.1515/trser-2015-0039.
Testo completoAbstract (sommario):
Abstract The paper presents the structure of the benthonic macro-invertebrates communities in the Berzasca, Sirinia, Liubcova, and Mraconia rivers. The results are based on quantitative benthos samples (95 samples), collected in July 2014 from 19 sampling stations within the study area. In longitudinal profile, the benthonic macro-invertebrate communities of the Sirinia, Liubcova and Berzasca rivers displays relatively large structural variability, while the communities of the Mraconia River displays smaller structural variability. The structure of the benthonic macro-invertebrate communities correlated with the biotope characteristics indicates the good ecological status of the analysed rivers, with the exception of the Berzasca River sector downstream of the town of Berzasca and immediately upstream of the Danube junction, a sector with moderate ecological status due to negative effects from man-made modifications in the lotic biotope of the sector.
13
Andrishak, R., e F. Hicks. "Simulating the effects of climate change on the ice regime of the Peace River". Canadian Journal of Civil Engineering 35, n. 5 (maggio 2008): 461–72. http://dx.doi.org/10.1139/l07-129.
Testo completoAbstract (sommario):
Winter can be a critical time on many rivers, during which ice conditions and a number of environmental factors can lead to rapidly developing and damaging flood events. Also, in northern Canada, rivers are important for both summer (ferry) and winter (ice bridge) transportation; however, during periods of variable ice conditions these transportation links are temporarily interrupted. As a result, northern communities can become isolated for periods of time. With climate warming becoming an increasing concern, it is important to know how elevated temperatures might affect river ice covers so that we can assess the implications for ice jam events, hydropower dam operation, and winter transportation. The Peace River in northern British Columbia and Alberta was used as a case study in this paper to assess the validity of a newly developed, public domain, thermo-hydraulic river ice model, River1D. The Canadian second-generation coupled global climate model (CGCM2) provided an offset for the historical air temperature input, and a future climate analogue for the mid-21st century ice regime was generated. The historical and future climate simulation results indicated significant potential reductions in the duration and extent of ice cover on the Peace River and a longer period over which the river will be impassible by ferry or ice bridge. Specifically, the number of days an ice bridge could be sustained at the Shaftesbury Ferry site was shown to decrease by 60% to 78%.
14
Rawlins, Michael A., Lei Cai, Svetlana L. Stuefer e Dmitry Nicolsky. "Changing characteristics of runoff and freshwater export from watersheds draining northern Alaska". Cryosphere 13, n. 12 (18 dicembre 2019): 3337–52. http://dx.doi.org/10.5194/tc-13-3337-2019.
Testo completoAbstract (sommario):
Abstract. The quantity and quality of river discharge in Arctic regions is influenced by many processes including climate, watershed attributes and, increasingly, hydrological cycle intensification and permafrost thaw. We used a hydrological model to quantify baseline conditions and investigate the changing character of hydrological elements for Arctic watersheds between Utqiagvik (formerly known as Barrow)) and just west of Mackenzie River over the period 1981–2010. A synthesis of measurements and model simulations shows that the region exports 31.9 km3 yr−1 of freshwater via river discharge, with 55.5 % (17.7 km3 yr−1) coming collectively from the Colville, Kuparuk, and Sagavanirktok rivers. The simulations point to significant (p<0.05) increases (134 %–212 % of average) in cold season discharge (CSD) for several large North Slope rivers including the Colville and Kuparuk, and for the region as a whole. A significant increase in the proportion of subsurface runoff to total runoff is noted for the region and for 24 of the 42 study basins, with the change most prevalent across the northern foothills of the Brooks Range. Relatively large increases in simulated active-layer thickness (ALT) suggest a physical connection between warming climate, permafrost degradation, and increasing subsurface flow to streams and rivers. A decline in terrestrial water storage (TWS) is attributed to losses in soil ice that outweigh gains in soil liquid water storage. Over the 30-year period, the timing of peak spring (freshet) discharge shifts earlier by 4.5 d, though the time trend is only marginally (p=0.1) significant. These changing characteristics of Arctic rivers have important implications for water, carbon, and nutrient cycling in coastal environments.
15
Morse, Brian, e Guy Trudeau. "Agencement de prises d'eau en région nordique". Canadian Journal of Civil Engineering 30, n. 1 (1 febbraio 2003): 69–76. http://dx.doi.org/10.1139/l02-035.
Testo completoAbstract (sommario):
The great quantity of small rivers in proximity of Canadian communities provide an excellent source of potable water. However, in our northern climate, intake structures must be built in rivers that are infested with ice. Since ice and hydraulic structures do not cohabit very well, the intakes must be designed to account for the many forms of ice. Referring to specific case studies, we examine the advantages and disavantages of conventional designs for municipal and industrial intakes. Conventional designs often employ weirs to raise water levels, whereas percolation systems withdraw water through the river bed. Their intake capacity is presented, and the use of retention basins to increase efficiency is discussed. Based on lessons learnt, we propose a design that meets the challenge of supplying water to a ski resort in typical hostile ice conditions for the Jacques-Cartier River in the Quebec City region.Key words: water intake, potable water, percolation, frazil ice, northern rivers.
16
Framenau, Volker W., Randolf Manderbach e Martin Baehr. "Riparian gravel banks of upland and lowland rivers in Victoria (south-east Australia): arthropod community structure and life-history patterns along a longitudinal gradient". Australian Journal of Zoology 50, n. 1 (2002): 103. http://dx.doi.org/10.1071/zo01039.
Testo completoAbstract (sommario):
Riparian sand and gravel banks are inhabited by a fauna that is well adapted to varying river water levels and frequent inundation of the banks. Arthropods found in these habitats were studied from November 1998 to January 1999 in the upper and lower floodplains of the main rivers and tributaries in ten major catchments in the Victorian Alps. Wolf spiders (Lycosidae, 68%) and ground beetles (Carabidae, 7.8%) were the most abundant arthropods, with densities averaging 14.6 ± 1.8 (s.e.) and 2.3 ± 0.4 individuals m–2 respectively. Species composition and wolf spider densities changed substantially between upland and lowland rivers. These differences correspond with changes in altitude, shading, and gravel and gravel bank size. Comparison of our results with similar studies conducted in temperate Northern Hemisphere floodplains showed significant differences. Carabidae, not Lycosidae, are the dominant arthropod group in Northern Hemisphere floodplains. Wolf spider densities are higher in upper than lower reaches of rivers in the Victorian Alps, but do not change along rivers in the Northern Hemisphere. In contrast, carabid beetles showed similar densities between upland and lowland floodplains in Victoria, but increase in density along rivers in the Northern Hemisphere. A second, monthly sampling program on gravel banks along the Avon River (Gippsland) over a one-year period in 1996 and 1997 provided information on the life histories of eight common gravel-bank arthropods: Venatrix lapidosa, V. arenaris, two undescribed Artoria species (‘A’, ‘B’) (Lycosidae), Eudalia macleayi, Elaphropus ovensensis, Perileptus constricticeps and an unidentified Loxandrus species (‘B’) (Carabidae). Artoria sp. A and sp. B are diplochronous. Despite its smaller size, Artoria sp. B matured one month after Artoria sp. A. Lower temperatures at upland streams and rivers, the typical habitat for Artoria sp. B, may delay its development in comparison with Artoria sp. A, which is generally found further downstream. The life histories of both lycosid spiders and carabid beetles, characterised by prolonged reproductive period and short larval development, appear to have some adaptive value in regard to the disturbance-prone environment.
17
Woo, Ming-ko, Robin Thorne e Laura Brown. "Comparison of runoff and river flow in two large northern basins". Hydrology Research 50, n. 6 (16 agosto 2018): 1609–22. http://dx.doi.org/10.2166/nh.2018.199.
Testo completoAbstract (sommario):
Abstract The magnitude and timing of water delivery in two large northern basins are analysed to clarify where runoff is generated and how their rivers acquire comparable regimes (or seasonal rhythms) of flow. These two rivers, the Mackenzie in Canada and the Yenisei in Russia, traverse similar latitudes, physiographic provinces, vegetation zones and climatic regions. Within the basins, mountainous terrain and high-precipitation sections usually yield large runoff, but low runoff comes from the plains, low plateaus and areas of aridity. Winter runoff is commonly low and snowmelt is responsible for annual peak runoff in most parts of these basins, though rainfall is a prominent runoff source in southern Yenisei. Many rivers in the drainage networks display a seasonal pattern that suggests the dominance of snowmelt to produce a spring freshet followed by a general decline in summer that diminishes to winter low flows. Regulation of reservoir outflow greatly distorts the natural flow regime. Yet, along the main river downstream of the reservoirs, the influx of tributary discharge can dilute such human influence. To truly understand how water is produced and transferred in large northern rivers, the spatial and temporal complexity of flow-generation mechanisms and storage effects need to be unravelled.
18
Huusko, Riina, Pekka Hyvärinen, Mikko Jaukkuri, Aki Mäki-Petäys, Panu Orell e Jaakko Erkinaro. "Survival and migration speed of radio-tagged Atlantic salmon (Salmo salar) smolts in two large rivers: one without and one with dams". Canadian Journal of Fisheries and Aquatic Sciences 75, n. 8 (agosto 2018): 1177–84. http://dx.doi.org/10.1139/cjfas-2017-0134.
Testo completoAbstract (sommario):
Connectivity problems in fish migration in regulated rivers have been widely studied, but few studies have rigorously compared parallel migration success between regulated and free-flowing rivers. Here, survival and migration speed of downstream migrating radio-tagged Atlantic salmon (Salmo salar) smolts were studied in two large neighboring rivers in the northern Baltic Sea area: one without and one with dams. Both rivers have a free-flowing upper section, where the survival and migration speed of salmon smolts were similar. Survival along the lower section of the free-flowing river was about six times higher than in the lower part of the regulated river with five hydropower plants. Migration speed of smolts was also significantly faster in the river without dams. These severe problems in downstream connectivity in the regulated river pose challenging tasks for restoration of salmon populations.
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Astrakhantseva, Olga Yu, e Oleg Yu Palkin. "Average annual background quantity of chemical elements and organic matter in the streams of the "River" environment flowing into Lake Baikal reservoirs". XXI century. Technosphere Safety 5, n. 4 (dicembre 2020): 433–47. http://dx.doi.org/10.21285/2500-1582-2020-4-433-447.
Testo completoAbstract (sommario):
The aim of the article is to assess the average long-term background hydrochemical input of chemical elements and organic matter from the flows of the natural component of the environment "Rivers" flowing into the South, Selenginsky, Middle and North reservoirs of Lake. Baikal. The results of calculation of the average annual amount (g/year) of chemical elements and organic matter (Na+, K+, Ca2+, Mg2+, Al, Si, Mn2+, Feобщ , SO42-, HCO3-, Cl-, NO3-, PO43-, Cr, Cu, Cd, Hg, Pb, Sr, Zn, Co, U, V, Mo, Cорг, Nорг, Pорг, Sорг, CO2, Ti) in the streams of the natural component of the environment "Rivers" flowing into the South, Selenginsky, Sredniy, Severny reservoirs of Lake Baikal are presented. The scale of the river chemical input into the reservoirs and the contribution of the "River" flows to the chemical balances of these reservoirs have been determined. It has been established that only in the Selenga reservoir the rivers carry a significant amount of matter (about 3%). The contribution of river flows to the chemical balance of the reservoir is 3.54; 5.4; 17.5 and 21.5% in the South, Selenga, Middle and North reservoirs, respectively. The rivers flowing into the Selenga reservoir carry 70.6% of the total amount of matter brought by the rivers into the lake. Whereas the rivers of the Northern, Middle and Southern reservoirs carry 14.0; 11.6 and 3.8% of the matter. Only in the Selenga and Northern reservoirs, the rivers (tributaries) are the main sources of macrocomponents (K+, Na+, Ca2+, SO42-, CO3-, Cl-), a number of microcomponents (Rb, Mo, Hg, Sr, and Cu and Zn in the Selenga river-), organic matter (Corgг, Norg, Porg), and biogenic components in the Selenga reservoir (NO3-).
20
Douglas, Michael M., Stuart E. Bunn e Peter M. Davies. "River and wetland food webs in Australia's wet - dry tropics: general principles and implications for management". Marine and Freshwater Research 56, n. 3 (2005): 329. http://dx.doi.org/10.1071/mf04084.
Testo completoAbstract (sommario):
The tropical rivers of northern Australia have received international and national recognition for their high ecological and cultural values. Unlike many tropical systems elsewhere in the world and their temperate Australian counterparts, they have largely unmodified flow regimes and are comparatively free from the impacts associated with intensive land use. However, there is growing demand for agricultural development and existing pressures, such as invasive plants and feral animals, threaten their ecological integrity. Using the international literature to provide a conceptual framework and drawing on limited published and unpublished data on rivers in northern Australia, we have derived five general principles about food webs and related ecosystem processes that both characterise tropical rivers of northern Australia and have important implications for their management. These are: (1) the seasonal hydrology is a strong driver of ecosystem processes and food-web structure; (2) hydrological connectivity is largely intact and underpins important terrestrial–aquatic food-web subsidies; (3) river and wetland food webs are strongly dependent on algal production; (4) a few common macroconsumer species have a strong influence on benthic food webs; and (5) omnivory is widespread and food chains are short. The implications of these ecosystem attributes for the management and protection of tropical rivers and wetlands of northern Australian are discussed in relation to known threats. These principles provide a framework for the formation of testable hypotheses in future research programmes.
21
Jerry, Dean R., e David J. Woodland. "Electrophoretic evidence for the presence of the undescribed ‘Bellinger’ catfish (Tandanus sp.) (Teleostei : Plotosidae) in four New South Wales mid-northern coastal rivers". Marine and Freshwater Research 48, n. 3 (1997): 235. http://dx.doi.org/10.1071/mf95141.
Testo completoAbstract (sommario):
Genetic data were collected from eight allopatric populations of the common freshwater catfish, Tandanus tandanus. Catfish sampled from the New South Wales (NSW) mid-northern coastal rivers of the Bellinger, Macleay, Hastings and Manning exhibited fixed allelic differences from T. tandanus from the type locality (Namoi River) at four enzymatic loci (GPI-1*, EST*, UMB-1* and UMB-2*), suggesting that, collectively, catfish from these four river systems constitute an undescribed species of Tandanus. Catfish from the northern coastal rivers of NSW (Tweed, Richmond and Clarence) displayed a complex pattern of population structure that was not fully resolved by the present study. More work is needed on the complex assemblage of populations of eel-tailed catfish in the eastern coastal drainages of Australia.
22
Niemelä, Riitta, Anna-Mari Auniola, Helena Jansson, Yevgeniy Ponomarenko, Felix Stolberg e Rikard Thurdin. "De-eutrophication of northern rivers and lakes - experiences from ProAQUA-project." River Systems 13, n. 3-4 (1 gennaio 2002): 423–35. http://dx.doi.org/10.1127/lr/13/2002/423.
Testo completo
23
Nilsson, Christer. "Change in riparian plant community composition along two rivers in northern Sweden". Canadian Journal of Botany 64, n. 3 (1 marzo 1986): 589–92. http://dx.doi.org/10.1139/b86-076.
Testo completoAbstract (sommario):
Large-scale spatial variation in vascular plant communities at 62 shoreline sites along the Piteälven and Laisälven–Vindelälven (rivers), in northern Sweden, was examined using two-way indicator species analysis (TWINSPAN). The first four clusters generated for each river were explained by shore substrate and wave and flow action. The Pitealven exhibited a sequence of discrete clusters, whereas along the Laisälven–Vindelälven a high degree of overlap between clusters was found. The results suggest overall “continua,” related to climatic gradients, along both rivers with other superimposed discontinuities related mainly to changes in substrate and flow action.
24
Huitu, Eeva, e Lauri Arvola. "Water Chemistry and Bacterioplankton in Two Subalpine Rivers in Finnish Lapland". Hydrology Research 34, n. 1-2 (1 febbraio 2003): 139–46. http://dx.doi.org/10.2166/nh.2003.0033.
Testo completoAbstract (sommario):
Water chemistry and bacterioplankton were analysed for two subalpine rivers, River Kidisjoki and River Utsjoki, in northernmost Finland. The data set is based on continuous runoff measurements and weekly chemical and biological samples. The data were collected during the open water period, from May to October, in year 2000. The runoff patterns during the summer were similar in the two rivers at though the size of the catchments is very different (the catchment of River Utsjoki 1,520 km2 and of River Kidisjoki 22 km2). For both rivers, variations in runoff were followed by variations in the water quality and bacterial densities. The measured chemical concentrations were usually the highest in the headwaters of river Kidisjoki, while in the lower Kidisjoki they were clearly lower than in Utsjoki. Bacterial densities were on average highest in Utsjoki and the strongest relationships between water chemistry and bacteria were found in Kidisjoki. Both the chemical concentrations and bacterial densities were low in the two rivers when compared to other studied rivers in northern Finland.
25
Anagnostoudi, Th, S. Papadopoulou, D. Ktenas, E. Gkadri, I. Pyliotis, N. Kokkidis e V. Panagiotopoulos. "THE OLVIOS, RETHIS AND INACHOS DRAINAGE SYSTEM EVOLUTION AND HUMAN ACTIVITIES INFLUNCE OF THEIR FUTURE EVOLUTION". Bulletin of the Geological Society of Greece 43, n. 2 (23 gennaio 2017): 548. http://dx.doi.org/10.12681/bgsg.11217.
Testo completoAbstract (sommario):
Olvios, Rethis and Inachos Rivers are multistory drainage systems that occur in Northern Peloponnesus, and at the present day they have and a reversed, North to South, flow element. Dervenios, Skoupeikos and Fonissa Rivers are the misfit streams of Olvios and revealed as juvenile streams and discharge to the Corinth gulf. Agiorgitikos River is the misfit stream of Rethis River and Seliandros River is the juvenile stream. Asopos, Nemeas and Rachiani Rives are the misfit streams of Inachos River and they also discharge to the Corinth gulf. Asopos River characterized as re-established stream. Physical factors such as tectonic regime (active and inactive faults), lithology, erosion and distance from the source influenced the three drainage systems evolution and could be influence them also in the future. The increase of human activities both in their southern parts and in the distal parts close to the coast could be change the physical evolution of the studied drainages, producing a new wind gap in the coastal area and a lake or a lagoon backwards of the coastal area, destroying villages and towns.
26
Bănăduc, Doru, e Angela Curtean-Bănăduc. "The “Porţile de Fier/Iron Gates” Nature Park (Romania) Some Danube Northern Tributaries Fish Fauna". Transylvanian Review of Systematical and Ecological Research 16, n. 3 (1 dicembre 2014): 165–70. http://dx.doi.org/10.1515/trser-2015-0040.
Testo completoAbstract (sommario):
Abstract The relative larger size of the Berzasca River, respectively the relatively constant environmental conditions, with relatively stenotopic ichthyocenosis, suffered small qualitative and quantitative fish fauna modifications in time, compared to the smaller rivers such as Sirinia, Liubcova/Oreviţa and Mraconia. The Danube “Iron Gates” I Lake influences the lower sectors of the studied rivers in term of fish species exchange. The accidental droughts in the karstic zones of the studied lotic sectors have a negative influence on the spatial continuity of the local fish fauna, and the climate change can increase these influence in the future. All the studied rivers play an important role for the near Danube “Iron Gates” I Lake lotic fish species of small-medium size, as reproduction and shelter habitats.
27
Salini, J., e JB Shaklee. "Genetic structure of barramundi (Lates calcarifer) stocks from northern Australia". Marine and Freshwater Research 39, n. 3 (1988): 317. http://dx.doi.org/10.1071/mf9880317.
Testo completoAbstract (sommario):
Barramundi, L. calcarifer, were collected from seven localities in the Northern Territory, the Daly, Finniss, Mary, Glyde, Roper and McArthur rivers and Blue Mud Bay, and from the Ord River in Western Australia. Barramundi were sampled seven times from the Daly and Finniss rivers over a 14-month period. In total, 46 loci were identified using starch-gel electrophoresis of enzymes and polyacrylamide electrophoresis of muscle proteins. Twelve loci were polymorphic at the P0.99 level. Most loci were in Hardy-Weinberg equilibrium. A contingency Χ2 analysis for homogeneity of alleles over all loci and all localities was highly significant (P < 0.001). Comparisons of data from adjacent pairs of localities revealed that the overall heterogeneity was attributable to heterogeneity among seven of the eight localities; the Daly and Finniss river areas were not significantly different from one another. No evidence of heterogeneity over time was found among the collections from the Daly River area. The considerable amount of heterogeneity observed suggests that each of these seven localities supports a genetically discrete stock of barramundi; this conclusion is consistent with the documented life history of Australian barramundi. The genetic heterogeneity of the stocks should be considered when management policies for L. calcarifer are being formulated.
28
Rennermalm, A. K., L. C. Smith, V. W. Chu, R. R. Forster, J. E. Box e B. Hagedorn. "Proglacial river stage, discharge, and temperature datasets from the Akuliarusiarsuup Kuua River northern tributary, Southwest Greenland, 2008–2011". Earth System Science Data 4, n. 1 (12 maggio 2012): 1–12. http://dx.doi.org/10.5194/essd-4-1-2012.
Testo completoAbstract (sommario):
Abstract. Pressing scientific questions concerning the Greenland ice sheet's climatic sensitivity, hydrology, and contributions to current and future sea level rise require hydrological datasets to resolve. While direct observations of ice sheet meltwater losses can be obtained in terrestrial rivers draining the ice sheet and from lake levels, few such datasets exist. We present a new hydrologic dataset from previously unmonitored sites in the vicinity of Kangerlussuaq, Southwest Greenland. This dataset contains measurements of river stage and discharge for three sites along the Akuliarusiarsuup Kuua (Watson) River's northern tributary, with 30 min temporal resolution between June 2008 and July 2011. Additional data of water temperature, air pressure, and lake stage are also provided. Flow velocity and depth measurements were collected at sites with incised bedrock or structurally reinforced channels to maximize data quality. However, like most proglacial rivers, high turbulence and bedload transport introduce considerable uncertainty to the derived discharge estimates. Eleven propagating error sources were quantified, and reveal that largest uncertainties are associated with flow depth observations. Mean discharge uncertainties (approximately the 68% confidence interval) are two to four times larger (&pm;19% to &pm;43%) than previously published estimates for Greenland rivers. Despite these uncertainties, this dataset offers a rare collection of direct measurements of ice sheet runoff to the global ocean and is freely available for scientific use at http://dx.doi.org/10.1594/PANGAEA.762818.
29
Shrestha, Manish, e Naresh Kazi Tamrakar. "Spatial variability of shallow groundwater level in the Northern Kathmandu Valley". Journal of Nepal Geological Society 55, n. 1 (4 giugno 2018): 45–54. http://dx.doi.org/10.3126/jngs.v55i1.22788.
Testo completoAbstract (sommario):
Groundwater is the water which is present in pore spaces and in the fractures of the geological materials beneath earth surface. Water is incompressible substance and presence of small amount of water in geological material modifies the behavior of geological material under stresses. Determination of engineering behavior of the geological material is almost impossible skipping the role of water. The objective of this study was to map and evaluate shallow groundwater level of the northern Kathmandu Valley covering main rivers such as the Bagmati River, Bishnumati River, Dhobi Khola and the Manahara Khola. These rivers flow from the North to the South across the sand rich sediment zone. Static groundwater levels of 239 wells were measured from different locations of the study area in April/March 2017 (Dry Season) and in August 2017 (Wet Season). Shallow groundwater level was measured from soil surface to water level using well water depth logger (Qin and Li, 1998). The result showed that groundwater level ranged from 0.6 m to 12.5
m in dry season and 0.1 m to 13 m in wet season. The groundwater level increased by average of 34.68% (n = 235) as compared to that in dry season. Increase in the groundwater level suggests recharge of groundwater in wet season of the study area. The flow pattern of groundwater levels from the study shows flow of shallow groundwater towards the major rivers of that particular river watershed. As a consequence, seepage flow and piping erosion is likely along the riverbank slopes. Increase in recharge of groundwater during wet season exhibits that the northern region of the Kathmandu Valley is potential for groundwater recharge and can be used to manage water for the dry period.
30
de Bont, C. "Digging the river: the historical geography of the Amstel area (800–1275 AD)". Netherlands Journal of Geosciences - Geologie en Mijnbouw 94, n. 4 (16 gennaio 2015): 353–60. http://dx.doi.org/10.1017/njg.2014.42.
Testo completoAbstract (sommario):
AbstractAround 800 AD the peatlands around Amstelland were drained by two rivers. The ‘northern’ Amstel discharged surplus water directly into Lake Almere, which from the 12th century onwards was enlarged to form the Sudersee (in Dutch: Zuiderzee). The ‘southern’ Amstel was a near-abandoned westernmost arm of the River Vecht discharging the poorly drained borderland around the river Vecht into Lake Almere/the Sudersee. As part of the reclamation of peatlands associated with agricultural activities between the end of the 10th and the mid-13th centuries, the rivers were connected via a canal, thus creating the river Amstel, as it is known today.
31
Nicieza, A. G., e F. Braña. "Relationships among Smolt Size, Marine Growth, and Sea Age at Maturity of Atlantic Salmon (Salmo salar) in Northern Spain". Canadian Journal of Fisheries and Aquatic Sciences 50, n. 8 (1 agosto 1993): 1632–40. http://dx.doi.org/10.1139/f93-184.
Testo completoAbstract (sommario):
Scale analysis indicated that two-sea-winter (2SW) Atlantic salmon (Salmo salar) had a greater growth increment during the first year at sea than 1SW of the same smolt year in the Rivers Narcea and Esva, but no differences were found between sea age-classes in the River Cares. Interannual variation in marine growth was synchronized among rivers. Variation among years was greater than variation between sea age-classes, suggesting that marine growth per se does not determine age at maturity. In the River Narcea, 2SW salmon were larger than 1SW at the end of the first marine period, but differences between sea age-groups were not significant in the other two rivers. Some of this variability could be attributed to differences in size at smolting; for two rivers (Esva and Cares), 1SW salmon had been larger as smolts than 2SW salmon. Length increment during the first marine growth period was inversely correlated with smolt size (age-1 smolts); in spite of that compensatory effect, large smolts tended to maintain their size advantage at the time of formation of the first marine annulus, as indicated by positive correlations between smolt size and length at the first sea winter.
32
Dahmardeh Behrooz, Reza, Abbas Esmaili-Sari e Paromita Chakraborty. "Distribution and ECo-Toxicological Risk Assessment of Legacy Persistent Organic Pollutants in Surface Water of Talar, Babolrood and Haraz Rivers". Water 12, n. 11 (4 novembre 2020): 3104. http://dx.doi.org/10.3390/w12113104.
Testo completoAbstract (sommario):
In the outer Alborz Range in the Northern Province of Iran, the Haraz, Talar and Babolrood Rivers are the three largest rivers where most of the agricultural, aquacultural and industrial activities are found. Total indicator polychlorinated biphenyls (iPCBs) ranged ND–474, ND–273 and ND–559 ng/L in Haraz, Talar and Babolrood Rivers, respectively. Significantly lower (p < 0.05) concentrations of DDT, lindane and dieldrin were observed in the upstream stations than downstream stations of both Babolrood and Haraz Rivers. However, in Talar River, PCB residues in upstream was significantly higher (p < 0.05) than downstream. Furthermore, PCB-28 in Talar River and PCB-101 and PCB-153 in Bablrood and Haraz Rivers were high in water samples at all stations. A significant difference was observed among the stations. In October, November and December, there was negligible variations in total PCB concentration among the stations. Alarming levels of some of the legacy persistent organic pollutants (POPs) may pose adverse effects on the aquatic species dwelling in the Talar, Babolrood and Haraz Rivers of Iran.
33
Power, Mary E. "Hydrologic and trophic controls of seasonal algal blooms in northern California rivers". Archiv für Hydrobiologie 125, n. 4 (19 ottobre 1992): 385–410. http://dx.doi.org/10.1127/archiv-hydrobiol/125/1992/385.
Testo completo
34
Islam, MJ, MS Rahman, Rubeca Fancy, AKMS Rahman, M. Shamsuzzoha e MAH Siddiqi. "Changes of organic phosphorus in river waters in northern Bangladesh". International Journal of Agricultural Research, Innovation and Technology 5, n. 2 (4 gennaio 2016): 31–36. http://dx.doi.org/10.3329/ijarit.v5i2.26267.
Testo completoAbstract (sommario):
The variability in phosphorus concentrations and the decomposition rates of organic phosphorus were measured in five selected rivers through four surveys in July and November of 2012, and February and May of 2013. After collection the water samples were incubated for 20 days in a dark incubator and the change of forms of phosphorus such as particulate organic phosphorus (POP), dissolved organic phosphorus (DOP) and dissolved inorganic phosphorus (DIP) were analyzed. By fitting the changes to two types of models, the decomposition rates of organic phosphorus were determined. The mean total organic phosphorus (TOP) decomposition rate coefficients in the studied rivers was 0.039 day-1. The average POP decomposition rate coefficient (POP?DOP?DIP model) was 0.038 day-1 while the mean DOP decomposition rate coefficient was 0.251 day-1. The decomposition rate coefficients measured in this study might be applicable for modeling of river water quality.Int. J. Agril. Res. Innov. & Tech. 5 (2): 31-36, December, 2015
35
Brodie, Jon E., e Alan W. Mitchell. "Nutrients in Australian tropical rivers: changes with agricultural development and implications for receiving environments". Marine and Freshwater Research 56, n. 3 (2005): 279. http://dx.doi.org/10.1071/mf04081.
Testo completoAbstract (sommario):
In tropical Australia, intensive studies of river suspended sediment (SS) and nutrient dynamics have been restricted to streams on the north-east coast between the Fitzroy and Normanby Rivers (Queensland), Magela Creek/East Alligator River (Northern Territory) and the Ord River (Western Australia). Historical conditions in these rivers were probably characterised by low–moderate SS concentrations and low concentrations of dissolved inorganic nitrogen and phosphorus in flow events. Introduction of agriculture has transformed SS and nutrient dynamics. Grazing has led to soil erosion and increased SS and particulate nutrient concentrations and fluxes in event flows. Fertilised cropping has increased nutrient inputs to catchments, where it forms a substantial proportion of the catchment area. Consequently, both particulate and dissolved inorganic nutrient concentrations and fluxes have increased. Australian tropical rivers have episodic flows, with most material transport occurring during large flow events. The restricted period of these highly energetic flows means little trapping of materials in waterways occurs. Loads are transported efficiently downstream and processes such as denitrification and in-channel sedimentation may be of limited importance. Owing to excessive nutrient inputs associated with agriculture, a number of northern freshwater, estuarine and coastal ecosystems are now eutrophic. Continued development, especially fertilised cropping, without adequate management of nutrient losses is likely to exacerbate these problems.
36
Gusarov, A. V., e L. F. Maksyutova. "The main regularities of the ratio between riverbed and basin components of erosion and suspended sediment yield in river basins of the USA". Geomorphology RAS, n. 1 (4 aprile 2019): 3–24. http://dx.doi.org/10.31857/s0435-4281201913-24.
Testo completoAbstract (sommario):
Suspended sediment yield is one of the objective and sufficiently accurate measures of erosion intensity in river basins. In first approximation, it can be divided into the riverbed component –r(rb), the products of vertical and horizontal riverbed deformations), and basin component – r(bas), the products of soil and gully erosion. An attempt was made to distinguish this erosion structure in the USA river basins based on the partition of suspended sediments of 224 rivers (based on the data from the US Geological Service on the average monthly water discharges and suspended sediment yields) according to the method proposed by one of the authors of the paper, as well as an assessment of its factor dependence.
The average r(rb) value for the analyzed rivers of the USA is 7.9±1.1%: for lowland rivers – 10.6±1.7%, for low-mountain (including uplands) rivers – 5.7±1.5%, for mid-mountain rivers – 4.3±1.5%. The geomorphic factor, landscape and climatic conditions within the river basins have a major impact on the suspended sediments flux ratio r(rb)/r(bas). Thus, in the USA plains, the largest average r(rb) portion is in the forest landscapes (taiga, mixed and broadleaf forests of the temperate zone, subtropical forests) – 10–15%. On the contrary, in the arid landscapes (semi-deserts) this value does not exceed 1%. Within these general trends, there are quite strong variations in the r(rb)/r(bas) ratios due to the changes in high river basin areas, agricultural activities and lithologic composition of the riverbed and floodplain sediments. There is an inverse hyperbolic relationship between the actual suspended sediment yield of rivers and the riverbed sediment portion (r(rb)), which is most manifested in the plains and low-mountains of the USA. It is also shown that a composition of the river basin parent (surficial) rocks does not play a significant role in the variability of the r(rb)/r(bas) at this scale of the study. A comparison of the r(rb)/r(bas)-estimates and their factor dependence on the US rivers with the rivers of Northern Eurasia (the territory of the former Soviet Union) makes it possible to reveal good convergence of the results obtained in these parts of the Earth, and to suggest the universal nature of the revealed regularities (in total for 684 river basins) for the whole temperate (partly for subtropical and tropical) zone of the Northern hemisphere of our planet.
37
Deng, Guangyi, Xiaohan Yao, Haibo Jiang, Yingyue Cao, Yang Wen, Wenjia Wang, She Zhao e Chunguang He. "Study on the Ecological Operation and Watershed Management of Urban Rivers in Northern China". Water 12, n. 3 (24 marzo 2020): 914. http://dx.doi.org/10.3390/w12030914.
Testo completoAbstract (sommario):
Small- and medium-sized rivers are facing a serious degradation of ecological function in water resource-scarce regions of Northern China. Reservoir ecological operation can restore the damaged river ecological environment. Research on reservoir ecological operation and watershed management of urban rivers is limited in cold regions of middle and high latitudes. In this paper, the urban section of the Yitong River was selected as the research object in Changchun, Northern China. The total ecological water demand and reservoir operation water (79.35 × 106 m3 and 15.52 × 106 m3, respectively) were calculated by the ecological water demand method, and a reservoir operation scheme was established to restore the ecological function of the urban section of the river. To examine the scientific basis and rationality of the operation scheme, the water quality of the river and physical habitat after carrying out the scheme were simulated by the MIKE 11 one-dimensional hydrodynamic-water quality model and the Physical Habitat Simulation Model (PHABSIM). The results indicate that the implementation of the operation scheme can improve the ecological environment of the urban section of the Yitong River. A reform scheme was proposed for the management of the Yitong River Basin based on the problems in the process of carrying out the operation schemes, including clarifying department responsibility, improving laws and regulations, strengthening service management, and enhancing public participation.
38
Baumgarten, Elisheva. "Daily Commodities and Religious Identity in the Medieval Jewish Communities of Northern Europe". Studies in Church History 50 (2014): 97–121. http://dx.doi.org/10.1017/s0424208400001674.
Testo completoAbstract (sommario):
The Hebrew chronicle written by Solomon b. Samson recounts the mass conversion of the Jews of Regensburg in 1096.’ The Jews were herded and forced into the local river where a ‘sign was made over the water, the sign of a cross’ and thus they were baptized, all together in the same river. The local German rivers play another role in the accounts of the turbulent events of the Crusade persecutions. They were also the place where Jews evaded conversion, drowning themselves in water, rather than being baptized by what the chronicles’ authors call the ‘stinking waters’ of Christianity. Reading these Hebrew chronicles, one is immediately struck by the tremendous revulsion expressed toward the waters of baptism. Indeed, in his analysis of the symbolic significance of the baptismal waters for medieval Jews, Ivan Marcus has suggested that baptism by force in the local rivers was so traumatic that they instituted a ritual response during the twelfth and thirteenth centuries. One component of the medieval Jewish child initiation ceremony to Torah study was performed on the banks of the river, expressing Jewish aversion to baptism (see Fig. i).
39
Milburn, David, e Terry D. Prowse. "The Effect of River-Ice Break-Up on Suspended Sediment and Select Trace-Element Fluxes". Hydrology Research 27, n. 1-2 (1 febbraio 1996): 69–84. http://dx.doi.org/10.2166/nh.1996.0020.
Testo completoAbstract (sommario):
Ice break-up on northern rivers presents a unique research challenge because of its dynamic nature and complexity of physical, chemical and biological processes. Rapidly moving ice, ice jamming, flood levels, and enhanced flow velocities can produce significant sediment transport and trace-element fluxes. Systematic sampling for these parameters, however, is rarely conducted because of logistical difficulties. This paper discusses the magnitude and relative significance of sediment and trace-element fluxes during break-up of the Liard River in northern Canada. Historical data for the open-water and stable ice-covered periods are compared to that measured during the 1987 and 1993 break-up events. Analysis reveals that a break-up pulse occurs during this period that if not accounted, can lead to significant underestimation of suspended sediment and trace-element fluxes. More generally, any estimates of annual sediment or trace-elements for northern rivers that do not include data for the critical break-up period must be regarded as being conservative.
40
Chiu, Chun Yen, Wei Lun Lee, Chung Yi Chung, Hwa Sheng Gau, Wen Liang Lai e Shao Wei Liao. "Distribution and Sources of PAHS and Sediment Properties in Southern Taiwan". Advanced Materials Research 518-523 (maggio 2012): 1301–6. http://dx.doi.org/10.4028/www.scientific.net/amr.518-523.1301.
Testo completoAbstract (sommario):
Abstract. The concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) and surface sediment properties were analyzed from 31 locations in Dapeng Bay and neighboring rivers (Kaoping River, Tungkang River and Lingbeng River), southern Taiwan. Principal component factor analysis (PCFA) was performed to explain the latent factors and spatial variations of sediment quality. And canonical discriminant analysis (CDA) was applied to identify the source of pollution of Dapeng Bay from neighboring rivers. The results show that the most important latent factors in Dapeng Bay and neighboring rivers on wet seasons are the soil texture caused factor, the PAHs caused factor, and the nutrient caused factor. Contour maps incorporating the factor scores showed phenanthrene (Phn) and pyrene (Pyr) of PAHs had the highest content at the entrance of the northern side of the lagoon. Benzo(a)pyrene (BaP) had the highest content located in mid-section of the Kaoping River and in Dapeng Bay. Total nitrogen (TN) and total phosphate (TP) had the highest content located in the last-section of Tungkang River. And CDA shows that sediment quality in Dapeng Bay was not similar to the other three rivers.
41
Orkhonselenge, Alexander, e Amgalan-Erdene Nyamjantsan. "Hydrogeochemical implications from Ider River in northern Mongolia". Mongolian Geoscientist, n. 47 (31 dicembre 2018): 45–52. http://dx.doi.org/10.5564/mgs.v0i47.1065.
Testo completoAbstract (sommario):
This study presents the hydrogeochemical implications resulted from Ider River, one of headwaters of Selenge River in northern Mongolia which is a main headwater of Lake Baikal in southeastern Russia, being included in a drainage basin of the North Arctic Ocean. Surface water and groundwater were collected and estimated with hydrogeochemical analyses of major ionic compositions in order to determine water quality in the catchment of Ider River in northern Mongolia. Result shows that the downstream of Ider River is more polluted than upstream of Ider River and Khunjil River, an inflow of the Ider River. Surface water of Ider River and groundwater in the catchment of the Ider River are comparable with their anions and cations. Ider River is highly enriched with an anion of Cl- in 2-3 times, cations of Na++K+ in 2-3 times and NH4+ in 0.5-1.0 times than those in groundwater in the catchment of Ider River. The hydrogeochemical results show that the surface water of Ider River is mainly polluted by solid wastes along its valley. More investigations with detail geochemical analyses are needed from the large rivers comprising surface water resource in Mongolia to review the hydrological evolution in Mongolia and Central Asia in the late Holocene.
42
Berggren, M., P. Bengtson, A. R. A. Soares e J. Karlsson. "Terrestrial support of zooplankton biomass in northern rivers". Limnology and Oceanography 63, n. 6 (20 luglio 2018): 2479–92. http://dx.doi.org/10.1002/lno.10954.
Testo completo
43
Gummer, William D., F. Malcolm Conly e Frederick J. Wrona. "Northern Rivers Ecosystem Initiative: Context and Prevailing Legacy". Environmental Monitoring and Assessment 113, n. 1-3 (9 marzo 2006): 71–85. http://dx.doi.org/10.1007/s10661-005-9097-1.
Testo completo
44
Romakkaniemi, A., I. Perä, L. Karlsson, E. Jutila, U. Carlsson e T. Pakarinen. "Development of wild Atlantic salmon stocks in the rivers of the northern Baltic Sea in response to management measures". ICES Journal of Marine Science 60, n. 2 (1 gennaio 2003): 329–42. http://dx.doi.org/10.1016/s1054-3139(03)00020-1.
Testo completoAbstract (sommario):
Abstract Since 1980, the abundance of wild Atlantic salmon has been monitored by means of catch records, adult counts, electrofishing and smolt trapping in six rivers flowing into the northern Baltic Sea. River abundance (spawners, parr and smolts) was compared with implemented large-scale and river-specific management measures and with natural factors potentially affecting abundance. Since the 1980s, the wild stocks have recovered in a synchronous cyclical pattern. The recovery occurred mainly in two jumps, first a sudden increase dating back to around 1990 and a second sharp rise in the late 1990s. River abundance of young salmon commonly rose about 10-fold and approached the previously estimated production capacity in some of the rivers. This positive development may be explained by a decline in fishing pressure together with covarying natural factors influencing survival and growth. The offshore fishery started to decline at the time of the first increase, while the reduction in the total allowable catches together with seasonal restrictions on the coastal fishery strengthened the second increase. Improved natural conditions seem to have increased both survival and escapement during the first rise. Spawners producing the second rise were the offspring of the spawners of the first rise. The outbreak of the M74 mortality syndrome among alevins reduced the abundance of several year-classes that hatched during the first half of the 1990s. In most rivers, the fraction of older and female fish in the spawning run has increased over the period, thereby increasing the reproductive capacity of the populations. No distinct effects of variations in river-specific management regimes were observed. Instead, the results emphasize the role of fisheries management in the open sea as well as in coastal waters, and also of non-human factors in controlling overall abundance of wild salmon in northern Baltic rivers.
45
Islam, Md Rakeb-Ul, Daniel J. Schmidt, David A. Crook e Jane M. Hughes. "Patterns of genetic structuring at the northern limits of the Australian smelt (Retropinna semoni) cryptic species complex". PeerJ 6 (3 maggio 2018): e4654. http://dx.doi.org/10.7717/peerj.4654.
Testo completoAbstract (sommario):
Freshwater fishes often exhibit high genetic population structure due to the prevalence of dispersal barriers (e.g., waterfalls) whereas population structure in diadromous fishes tends to be weaker and driven by natal homing behaviour and/or isolation by distance. The Australian smelt (Retropinnidae:Retropinna semoni) is a native fish with a broad distribution spanning inland and coastal drainages of south-eastern Australia. Previous studies have demonstrated variability in population genetic structure and movement behaviour (potamodromy, facultative diadromy, estuarine residence) across the southern part of its geographic range. Some of this variability may be explained by the existence of multiple cryptic species. Here, we examined genetic structure of populations towards the northern extent of the species’ distribution, using ten microsatellite loci and sequences of the mitochondrial cytbgene. We tested the hypothesis that genetic connectivity among rivers should be low due to a lack of dispersal via the marine environment, but high within rivers due to dispersal. We investigated populations corresponding with two putative cryptic species, SEQ-North (SEQ-N), and SEQ-South (SEQ-S) lineages occurring in south east Queensland drainages. These two groups formed monophyletic clades in the mtDNA gene tree and among river phylogeographic structure was also evident within each clade. In agreement with our hypothesis, highly significant overallFSTvalues suggested that both groups exhibit very low dispersal among rivers (SEQ-SFST= 0.13; SEQ-NFST= 0.27). Microsatellite data indicated that connectivity among sites within rivers was also limited, suggesting dispersal may not homogenise populations at the within-river scale. Northern groups in the Australian smelt cryptic species complex exhibit comparatively higher among-river population structure and smaller geographic ranges than southern groups. These properties make northern Australian smelt populations potentially susceptible to future conservation threats, and we define eight genetically distinct management units along south east Queensland to guide future conservation management. The present findings at least can assist managers to plan for effective conservation and management of different fish species along coastal drainages of south east Queensland, Australia.
46
Kelderman, P., e P. Batima. "Water quality assessment of rivers in Mongolia". Water Science and Technology 53, n. 10 (1 maggio 2006): 111–19. http://dx.doi.org/10.2166/wst.2006.304.
Testo completoAbstract (sommario):
A study was made on the water quality of the rivers in Mongolia over the years 1949–1990 for the three river basins in the country. In most of the 72 monitoring stations, the water quality is governed by geological and hydrological characteristics; bicarbonate and calcium are the most abundant major ions. No significant trends were observed between river discharges and total dissolved solids contents. The sediment yields (expressed in the run-off of total suspended solids, TSS) were always low, viz. between 0.02 and 20 × 103 kg TSS/km2.yr. In general, the rivers in Mongolia showed low pollution levels for organic pollution, phosphorus, nitrogen, etc., and no time trends were observed in this respect. This does not hold, however, for the northern Tuul River, where especially high BOD and ammonium values were found. This can probably be ascribed to the presence of industries and larger cities, as well as agricultural practices. The rivers in Mongolia can generally be classified as “clean” or “of acceptable quality”. In contrast, the Tuul River was shown to be “moderately polluted”, with a deteriorating trend in water quality over recent years.
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Papadakis, Emmanouil-Nikolaos, Aggeliki Tsaboula, Zisis Vryzas, Athina Kotopoulou, Katerina Kintzikoglou e Euphemia Papadopoulou-Mourkidou. "Pesticides in the rivers and streams of two river basins in northern Greece". Science of The Total Environment 624 (maggio 2018): 732–43. http://dx.doi.org/10.1016/j.scitotenv.2017.12.074.
Testo completo
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Singh, Arvind, e R. Ramesh. "Contribution of Riverine Dissolved Inorganic Nitrogen Flux to New Production in the Coastal Northern Indian Ocean: An Assessment". International Journal of Oceanography 2011 (8 giugno 2011): 1–7. http://dx.doi.org/10.1155/2011/983561.
Testo completoAbstract (sommario):
Rivers are known to be one of the major sources of dissolved inorganic nitrogen (DIN) to the coastal ocean and contribute to the primary productivity in the sunlit upper ocean. This study provides an analysis of DIN fluxes and its possible contribution to new production in the coastal northern Indian Ocean based on the literature data. Most of the riverine DIN flux (~81% in the case of the Arabian Sea and 96% in the case of the Bay of Bengal) is not transported to the coastal ocean and is consumed on the course of the rivers or in the estuaries. Coastal Bay of Bengal and Arabian Sea receive ~0.38 Tg N year−1 (1 Tg = 1012 g) and ~0.06 Tg N year−1, respectively, through rivers. A large variation in the contribution of DIN through river fluxes to new production is found in both of these basins.
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McCormick, Stephen D., Richard A. Cunjak, Brian Dempson, Michael F. O'Dea e Judith B. Carey. "Temperature-related loss of smolt characteristics in Atlantic salmon (Salmo salar) in the wild". Canadian Journal of Fisheries and Aquatic Sciences 56, n. 9 (1 settembre 1999): 1649–67. http://dx.doi.org/10.1139/f99-099.
Testo completoAbstract (sommario):
Atlantic salmon (Salmo salar) that had previously been released as fry in tributaries of the Connecticut River were captured from 1993 to 1997 during their normal spring smolt migration 198 km from the mouth of the river. Smolts had peak levels of gill Na+,K+-ATPase activity and salinity tolerance early in migration (early May), indicating physiological readiness to enter seawater. Significant decreases in gill Na+,K+-ATPase activity (29-66%) and salinity tolerance were seen in smolts at the end of the migratory period (late May and early June). Reduced gill Na+,K+-ATPase activity occurred earlier in warm years and was directly related to the degree-days during migration (r2 = 0.75). Reduced gill Na+,K+-ATPase activity was found at the end of migration in warmer, southern rivers (Connecticut River and Penobscot River, Maine) but not in northern rivers (Catamaran Brook, New Brunswick, and Conne River, Newfoundland). Both hatchery- and stream-reared fish held in the laboratory exhibited a more rapid loss of physiological smolt characteristics when held at higher temperature. The results indicate that late migrants in southern rivers lose physiological smolt characteristics due to high temperatures during spring migration. Delays in migration, such as those that occur at dams, may have negative impacts on smolt survival in warmer rivers.
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Kraus, R., N. Supić e R. Precali. "Factors favouring large organic production in the northern Adriatic: towards the northern Adriatic empirical ecological model". Ocean Science Discussions 12, n. 3 (25 giugno 2015): 1219–62. http://dx.doi.org/10.5194/osd-12-1219-2015.
Testo completoAbstract (sommario):
Abstract. Influenced by one of the largest Mediterranean rivers, Po, the northern Adriatic production is highly variable seasonally and interannually. The changes are especially pronounced between winters and seemingly reflect on total Adriatic bioproduction of certain species (anchovy). We analysed the long-term changes in the phytoplankton production at the transect in the region, as derived from monthly oceanographic cruises, in relation to concomitant geostrophic currents distribution in the area and in the Po River discharge rates in days preceding the cruises. In winter and early spring the phyto-abundances depended on existing circulation fields, in summer and autumn they were related to 1–15 days earlier Po River discharge rates and on concomitant circulation fields, while in late spring phyto-abundances increased 1–3 days after high Po River discharge rates regardless of circulation fields. During the entire year the phyto-abundances were dependant on forcing of the previous 1–12 months of surface fluxes and/or Po River rates. Large February blooms are, as well as February circulation patterns, precondited by low evaporation rates in previous November. From 1990 to 2004 a shift towards large winter bioproduction induced by circulation changes appeared. Performed investigations represent the preliminary actions in building of an empirical ecological model of the northern Adriatic which can be used in the sustainable economy of the region, however also in validation of the numerical ecological model of the region, which is currently being developed.