Academic literature on the topic 'Turbid freshwaters'
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Journal articles on the topic "Turbid freshwaters"
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Grobbelaar, Johan U. "The contribution of phytoplankton in turbid freshwaters to their trophic status." SIL Proceedings, 1922-2010 23, no. 2 (August 1988): 1020–21. http://dx.doi.org/10.1080/03680770.1987.11899761.
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Grobbelaar, Johan U. "The contribution of phytoplankton productivity in turbid freshwaters to their trophic status." Hydrobiologia 173, no. 2 (March 1989): 127–33. http://dx.doi.org/10.1007/bf00015522.
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Barouillet, Cécilia, Brian F. Cumming, Kathleen R. Laird, Christopher J. Perrin, and Daniel T. Selbie. "Influence of glacial flour on the primary and secondary production of sockeye salmon nursery lakes: a comparative modern and paleolimnological study." Canadian Journal of Fisheries and Aquatic Sciences 76, no. 12 (December 2019): 2303–14. http://dx.doi.org/10.1139/cjfas-2018-0372.
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The increasing rate of glacier retreat and turbid glacial runoff can have a strong influence on freshwater ecosystems. Seton and Anderson lakes (British Columbia, Canada) are sockeye salmon (Oncorhynchus nerka) nursery systems. Since the 1940s, the Bridge River Diversion (BRD) introduced glacially turbid water into Seton Lake. To assess the impact of the BRD on the production of Seton Lake, we combined data from limnological surveys with the analysis of subfossil cladocerans and diatoms from sediment cores, using Anderson Lake as a reference. The modern data indicate that the euphotic zone is 14 m shallower and the cladoceran density and biomass are significantly lower in Seton Lake in comparison with Anderson Lake. The paleo-data indicate that following the BRD, the sedimentary fluxes of cladoceran and diatom declined 2- to 10-fold in Seton Lake and remained low thereafter. Together, our data support declines in primary and secondary producers following the BRD, likely due to changes in light penetration and (or) other indirect influence, and provides insights into the impact of turbid meltwater on the biological production of downstream lakes.
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Abrahams, Mark V. "Risk of Predation and Its Influence on the Relative Competitive Abilities of Two Species of Freshwater Fishes." Canadian Journal of Fisheries and Aquatic Sciences 51, no. 7 (July 1, 1994): 1629–33. http://dx.doi.org/10.1139/f94-163.
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Experiments were conducted with fathead minnow (Pimephales promelas) and brook stickleback (Culaea inconstans) to determine whether their relative feeding rates were affected by risk of predation. Six groups of both species were observed foraging for food provided by an automated feeder while two parameters were manipulated: the presence or absence of a predator, yellow perch (Perca flavescens), and clear or turbid water. It was hypothesized that the armour and spines of brook stickleback would be of greatest benefit during a direct encounter with a predator. I attempted to simulate this condition with turbid water and predator present. Feeding rates of the two species were significantly different, with fathead minnow feeding at a greater rate than brook stickleback in the absence of a predator. In the presence of a predator the feeding rate of fathead minnow declined significantly whereas that of brook stickleback was unaffected. This resulted in similar feeding rates for the two species in the presence of a predator. Results demonstrate that risk of predation can alter the relative competitive abilities of two species in situations where one species possesses a morphological adaptation against predation. In the absence of predators, these traits may be detrimental in interspecific competition for food.
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Lobo, Felipe L., Maycira Costa, Stephen Phillips, Erika Young, and Cory McGregor. "Light backscattering in turbid freshwater: a laboratory investigation." Journal of Applied Remote Sensing 8, no. 1 (June 25, 2014): 083611. http://dx.doi.org/10.1117/1.jrs.8.083611.
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El-Alem, Anas, Karem Chokmani, Aarthi Venkatesan, Lhissou Rachid, Hachem Agili, and Jean-Pierre Dedieu. "How Accurate Is an Unmanned Aerial Vehicle Data-Based Model Applied on Satellite Imagery for Chlorophyll-a Estimation in Freshwater Bodies?" Remote Sensing 13, no. 6 (March 17, 2021): 1134. http://dx.doi.org/10.3390/rs13061134.
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Optical sensors are increasingly sought to estimate the amount of chlorophyll a (chl_a) in freshwater bodies. Most, whether empirical or semi-empirical, are data-oriented. Two main limitations are often encountered in the development of such models. The availability of data needed for model calibration, validation, and testing and the locality of the model developed—the majority need a re-parameterization from lake to lake. An Unmanned aerial vehicle (UAV) data-based model for chl_a estimation is developed in this work and tested on Sentinel-2 imagery without any re-parametrization. The Ensemble-based system (EBS) algorithm was used to train the model. The leave-one-out cross validation technique was applied to evaluate the EBS, at a local scale, where results were satisfactory (R2 = Nash = 0.94 and RMSE = 5.6 µg chl_a L−1). A blind database (collected over 89 lakes) was used to challenge the EBS’ Sentine-2-derived chl_a estimates at a regional scale. Results were relatively less good, yet satisfactory (R2 = 0.85, RMSE= 2.4 µg chl_a L−1, and Nash = 0.79). However, the EBS has shown some failure to correctly retrieve chl_a concentration in highly turbid waterbodies. This particularity nonetheless does not affect EBS performance, since turbid waters can easily be pre-recognized and masked before the chl_a modeling.
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Ohashi, Yoshihiko, Shigeru Aoki, Yoshimasa Matsumura, Shin Sugiyama, Naoya Kanna, and Daiki Sakakibara. "Vertical distribution of water mass properties under the influence of subglacial discharge in Bowdoin Fjord, northwestern Greenland." Ocean Science 16, no. 3 (May 4, 2020): 545–64. http://dx.doi.org/10.5194/os-16-545-2020.
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Abstract. Subglacial discharge has significant impacts on water circulation, material transport, and biological productivity in proglacial fjords of Greenland. To help clarify the fjord water properties and the effect of subglacial discharge, we investigated the properties of vertical water mass profiles of Bowdoin Fjord in northwestern Greenland based on summer hydrographic observations, including turbidity, in 2014 and 2016. We estimated the fraction of subglacial discharge from the observational data and interpreted the observed differences in subglacial plume behavior between two summer seasons with the numerical model results. At a depth of 15–40 m, where the most turbid water was observed, the maximum subglacial discharge fractions near the ice front were estimated to be ∼6 % in 2014 and ∼4 % in 2016. The higher discharge fraction in 2014 was likely due to stronger stratification, as suggested by the numerical experiments performed with different initial stratifications. Turbidity near the surface was higher in 2016 than in 2014, suggesting a stronger influence of turbid subglacial discharge. The higher turbidity in 2016 could primarily be attributed to a greater amount of subglacial discharge, as inferred from the numerical experiments forced by different amounts of discharge. This study suggests that both fjord stratification and the amount of discharge are important factors in controlling the vertical distribution of freshwater outflow.
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Kwon, S. B., H. W. Ahn, C. J. Ahn, and C. K. Wang. "A case study of dissolved air flotation for seasonal high turbidity water in Korea." Water Science and Technology 50, no. 12 (December 1, 2004): 245–53. http://dx.doi.org/10.2166/wst.2004.0720.
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A DAF (Dissolved-Air-Flotation) process has been designed considering raw water quality characteristics in Korea. Although direct filtration is usually operated, DAF is operated when freshwater algae blooms occur or raw water turbidity becomes high. Pre-sedimentation is operated in case when the raw water turbidity is very high due to rainstorms. A main feature of this plant is that the operation mode can be changed (controlled) based on the characteristics of the raw water to optimize the effluent quality and the operation costs. Treatment capacity (surface loading rate) and efficiency of DAF was found to be better than the conventional sedimentation process. Moreover, low-density particles (algae and alum flocs) are easily separated while the removal of them by sedimentation is more difficult. One of the main concerns for DAF operation is a high raw water turbidity. DAF is not adequate for raw water, which is more turbid than 100 NTU. In order to avoid this problem, pre-sedimentation basins are installed in the DAF plant to decrease the turbidity of the DAF inflow. For simulation of the actual operation, bench and full-scale tests were performed for highly turbid water conditions. Consequently, it is suggested that pre-sedimentation with optimum coagulation prior to DAF is the appropriate treatment scheme.
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Nishizawa, Bungo, Naoya Kanna, Yoshiyuki Abe, Yoshihiko Ohashi, Daiki Sakakibara, Izumi Asaji, Shin Sugiyama, Atsushi Yamaguchi, and Yutaka Watanuki. "Contrasting assemblages of seabirds in the subglacial meltwater plume and oceanic water of Bowdoin Fjord, northwestern Greenland." ICES Journal of Marine Science 77, no. 2 (December 14, 2019): 711–20. http://dx.doi.org/10.1093/icesjms/fsz213.
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Abstract In Greenland, tidewater glaciers discharge turbid subglacial freshwater into fjords, forming plumes near the calving fronts, and these areas serve as an important foraging habitat for seabirds. To investigate the effect of subglacial discharge on the foraging assemblages of surface feeders and divers in a glacial fjord, we conducted boat-based seabird surveys, near-surface zooplankton samplings, and hydrographic measurements at Bowdoin Fjord, northwestern Greenland in July. Foraging surface feeders (black-legged kittiwake Rissa tridactyla, glaucous gull Larus hyperboreus, and northern fulmar Fulmarus glacialis) aggregated within a plume-affected area in front of Bowdoin Glacier. This area was characterized by highly turbid subglacial meltwater and abundant large-sized zooplankton including Calanus hyperboreus, chaetognaths, and ctenophores near the surface. Surface feeders fed on these aggregated prey presumably transported to the surface by strong upwelling of subglacial meltwater. In contrast, divers (little auk Alle alle, thick-billed murre Uria lomvia, and black guillemot Cepphus grylle) foraged outside the fjord, where turbidity was low and jellyfish and Calanus copepods dominated under the influence of Atlantic water. Our study indicates spatial segregation between surface feeders and divers in a glacial fjord; surface feeders are not hindered by turbidity if taking prey at the surface, whereas divers need clear water.
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Cantonati, Poikane, Pringle, Stevens, Turak, Heino, Richardson, et al. "Characteristics, Main Impacts, and Stewardship of Natural and Artificial Freshwater Environments: Consequences for Biodiversity Conservation." Water 12, no. 1 (January 16, 2020): 260. http://dx.doi.org/10.3390/w12010260.
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In this overview (introductory article to a special issue including 14 papers), we consider all main types of natural and artificial inland freshwater habitas (fwh). For each type, we identify the main biodiversity patterns and ecological features, human impacts on the system and environmental issues, and discuss ways to use this information to improve stewardship. Examples of selected key biodiversity/ecological features (habitat type): narrow endemics, sensitive (groundwater and GDEs); crenobionts, LIHRes (springs); unidirectional flow, nutrient spiraling (streams); naturally turbid, floodplains, large-bodied species (large rivers); depth-variation in benthic communities (lakes); endemism and diversity (ancient lakes); threatened, sensitive species (oxbow lakes, SWE); diverse, reduced littoral (reservoirs); cold-adapted species (Boreal and Arctic fwh); endemism, depauperate (Antarctic fwh); flood pulse, intermittent wetlands, biggest river basins (tropical fwh); variable hydrologic regime—periods of drying, flash floods (arid-climate fwh). Selected impacts: eutrophication and other pollution, hydrologic modifications, overexploitation, habitat destruction, invasive species, salinization. Climate change is a threat multiplier, and it is important to quantify resistance, resilience, and recovery to assess the strategic role of the different types of freshwater ecosystems and their value for biodiversity conservation. Effective conservation solutions are dependent on an understanding of connectivity between different freshwater ecosystems (including related terrestrial, coastal and marine systems).
Dissertations / Theses on the topic "Turbid freshwaters"
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Woo, Lirasari, and n/a. "Determination of phosphorus in turbid freshwaters using alkaline peroxodisulphate digestion." University of Canberra. Resource, Environmental & Heritage Sciences, 1995. http://erl.canberra.edu.au./public/adt-AUC20061110.164738.
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Methods for determining phosphorus in turbid lake and river water using
heating with an autoclave or a microwave and employing alkaline
peroxodisulphate digestion have been investigated. Suspensions (up to 100
ugP/L) of two standard reference materials (NIES No. 3 Chlorella and NEES No.
2 Pond Sediment) were used to optimised procedures.
Quantitative recoveries of phosphorus were achieved when the final
solution to be digested contained 0.045 M potassium peroxodisulphate and 0.04
M sodium hydroxide and solutions were autoclaved at 120°C for 60 min. or
microwaved at 450 Watts for 5-10 min. Complete recoveries of phosphorus (99-
103%) from 20 ugP/U 50 ugP/L and 100 ugP/L Chlorella suspensions were
obtained using autoclave and microwave heating. For the Pond Sediment
suspensions complete recoveries of phosphorus (99-104%) from the 20 ugP/L
and 50 ugP/L were obtained using both heating methods. Higher recoveries from
the 100 u.gP/L Pond Sediment suspensions were obtained using microwave
heating (96±1%) than autoclaving (88±5%). Further analysis of Pond Sediment
suspensions using the autoclave heating showed that complete recovery of
phosphorus (98±l%) from 60 ngP/L suspensions was achieved with incomplete
recoveries (92.3±0.7%, 91�2% and 91�1%) from 70 ugP/L, 80 ugP/L and 90 ug
P/L suspensions respectively. Recoveries of phosphorus compounds
(orthophosphate and phosphonates) added to distilled water and turbid lake water
were near quantitative (91-117%) for both digestion methods.
A range of turbid lake and river water (TP = 57-106 ugP/L; Turbidity =
16-200 NTU) were analysed for total phosphorus (TP) using the optimised
alkaline peroxodisulphate digestion procedures and the APHA AWWA WPCF,
sulphuric acid - nitric acid digestion procedure. No difference in total
phosphorus measurements were found between the microwave digestion
procedure and the APHA AWWA WPCF, nitric acid - sulphuric acid procedure.
The autoclave procedure gave significantly lower recoveries of phosphorus
(p<0.01), however, differences were only 2-8%.
The effect of freezing (-20�C) water samples without or with the addition
of 1% hydrochloric acid before determination of total phosphorus (TP) and total
dissolved phosphorus (TDP) was also investigated. No significant change in total
phosphorus occurred when samples were stored frozen without the addition of
1% hydrochloric acid in high and low density polyethylene bottles for up to 20
weeks and 2 weeks respectively after collection. Significant changes were found
in total dissolved phosphorus when samples were stored frozen without the
addition of 1% hydrochloric acid in high and low density polyethylene bottles
after 1 day and 2 weeks respectively.
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Umorin, Mikhail Pavlovich Lind Owen T. "Phytoplankton growth model for a turbid pulsed aquatic ecosystem." Waco, Tex. : Baylor University, 2006. http://hdl.handle.net/2104/4194.
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Childs, Amber-Robyn. "Movement patterns of spotted grunter, Pomadasys commersonnii (Haemulidae), in a highly turbid South African estuary." Thesis, Rhodes University, 2006. http://hdl.handle.net/10962/d1005149.
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The principal objective of this thesis was to gain an understanding of the movement patterns of spotted grunter Pomadasys commersonnii, an estuarine-dependent fishery species, in the turbid, freshwater dominated Great Fish Estuary. Both manual and automated telemetry methods were used to monitor the movements of spotted grunter during two separate studies conducted in summer and spring 2003 and 2004. Acoustic transmitters were surgically implanted into twenty spotted grunter with lengths between 263 and 387 mm TL in the first study and twenty spotted grunter ranging between 362 and 698 mm TL in the second study. The specific objectives were to gain an understanding of (i) the time spent in the estuarine environment (ii) the space use and home range size, and (iii) the abiotic factors governing the movement patterns of spotted grunter in the estuary. The nursery function of estuarine environments was highlighted in this study as adolescent spotted grunter spent a significantly larger proportion of their time in the estuary than adult fish (p < 0.0001; R² = 0.62). The increased frequency of sea trips, with the onset of sexual maturity, provided testimony of the end of the estuarinedependent phase of their life-cycle. Although considered to be predominantly marine, the adult spotted grunter in the Great Fish Estuary utilised the estuary for considerable periods. Adults are thought to frequent estuaries to forage, seek shelter and to possibly rid themselves of parasites. During this study, the number of sea trips made by tagged fish ranged from 0 to 53, and the duration ranged from 6 hours to 28 days. The tidal phase and time of day had a significant effect (p < 0.05) on the sea trips undertaken by fish. Most tagged spotted grunter left the estuary during the night (84%) on the outgoing tide, and most returned in the evening (77%) during the incoming tide. Sea temperature (p < 0.0001; R² = 0.34), barometric pressure (p = 0.004; R² = 0.19) and wind (p = 0.01) had a significant effect on the number of spotted grunter recorded in the estuary. Spotted grunter were more prone to return to the estuary after high barometric pressure, when low sea temperatures (upwelling events) prevailed. There was a significant positive relationship between home range size and fish length (p = 0.004; R² = 0.20). Small spotted grunter (< 450 mm TL) appeared to be highly resident, with a small home range (mean size = 129 167 m²), that was generally confined to a single core area. Larger individuals (> 450 mm TL) occupied larger home ranges (mean size = 218 435 m²) with numerous core areas. The home ranges of small and large spotted grunter overlapped considerably yielding evidence of two high use areas, situated 1.2 km and 7 km from the mouth of the Great Fish Estuary. Tagged spotted grunter were located in a wide range of salinity, turbidity and temperature, but were found to avoid temperatures below 16 ºC. The daily change in environmental variables (salinity, temperature and turbidity) had a significant effect on the change in fish position in the estuary (p < 0.0001; R² = 0.38). The distribution of tagged spotted grunter, particularly the larger individuals, in the Great Fish Estuary was influenced by the tidal phase (p < 0.05); they moved upriver on the incoming tide and downriver on the outgoing tide. This study provides an understanding of the movement patterns of spotted grunter in the estuary and between the estuarine and marine environments. Consequently, it provides information that will assist in the design of a management plan to promote sustainability of this important fishery species. The techniques used and developed in this study also have direct application for further studies on other important estuarinedependent fishery species.
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Caroff-André, Anne. "Etude des differents types cellulaires de l'epithelium branchial de deux poissons euryhalins : le guppy et la truitelle, et d'un poisson stenohalin : le turbot, leurs significations fonctionnelles." Paris 6, 1987. http://www.theses.fr/1987PA066295.
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Caracterisation de differents types cellulaires de l'epithelium branchial de deux poissons euryhalins : le guppy et la truitelle et d'un poisson stenohalin : le turbot. Le resultat majeur de ce travail concerne l'observation de plusieurs types de cellules a chlorure des epitheliums branchiaux de poissons marins et d'eau douce. L'osmoregulation a ce niveau est observee
Books on the topic "Turbid freshwaters"
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International Association of Phytoplankton Taxonomy and Ecology. Workshop. Phytoplankton in turbid environments: Rivers and shallow lakes : proceedings of the 9th Workshop of the International Association of Phytoplankton Taxonomy and Ecology (IAP) held in Mont Rigi (Belgium), 10-18 July 1993. Dordrecht: Kluwer Academic Publishers, 1994.
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(Editor), J. P. Descy, Colin S. Reynolds (Editor), and Judit Padisák (Editor), eds. Phytoplankton in Turbid Environments: Rivers and Shallow Lakes (Developments in Hydrobiology). Springer, 2007.
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Vuorinen, Ilppo. Post-Glacial Baltic Sea Ecosystems. Oxford University Press, 2018. http://dx.doi.org/10.1093/acrefore/9780190228620.013.675.
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Post-glacial aquatic ecosystems in Eurasia and North America, such as the Baltic Sea, evolved in the freshwater, brackish, and marine environments that fringed the melting glaciers. Warming of the climate initiated sea level and land rise and subsequent changes in aquatic ecosystems. Seminal ideas on ancient developing ecosystems were based on findings in Swedish large lakes of species that had arrived there from adjacent glacial freshwater or marine environments and established populations which have survived up to the present day. An ecosystem of the first freshwater stage, the Baltic Ice Lake initially consisted of ice-associated biota. Subsequent aquatic environments, the Yoldia Sea, the Ancylus Lake, the Litorina Sea, and the Mya Sea, are all named after mollusc trace fossils. These often convey information on the geologic period in question and indicate some physical and chemical characteristics of their environment. The ecosystems of various Baltic Sea stages are regulated primarily by temperature and freshwater runoff (which affects directly and indirectly both salinity and nutrient concentrations). Key ecological environmental factors, such as temperature, salinity, and nutrient levels, not only change seasonally but are also subject to long-term changes (due to astronomical factors) and shorter disturbances, for example, a warm period that essentially formed the Yoldia Sea, and more recently the “Little Ice Age” (which terminated the Viking settlement in Iceland).There is no direct way to study the post-Holocene Baltic Sea stages, but findings in geological samples of ecological keystone species (which may form a physical environment for other species to dwell in and/or largely determine the function of an ecosystem) can indicate ancient large-scale ecosystem features and changes. Such changes have included, for example, development of an initially turbid glacial meltwater to clearer water with increasing primary production (enhanced also by warmer temperatures), eventually leading to self-shading and other consequences of anthropogenic eutrophication (nutrient-rich conditions). Furthermore, the development in the last century from oligotrophic (nutrient-poor) to eutrophic conditions also included shifts between the grazing chain (which include large predators, e.g., piscivorous fish, mammals, and birds at the top of the food chain) and the microbial loop (filtering top predators such as jellyfish). Another large-scale change has been a succession from low (freshwater glacier lake) biodiversity to increased (brackish and marine) biodiversity. The present-day Baltic Sea ecosystem is a direct descendant of the more marine Litorina Sea, which marks the beginning of the transition from a primeval ecosystem to one regulated by humans. The recent Baltic Sea is characterized by high concentrations of pollutants and nutrients, a shift from perennial to annual macrophytes (and more rapid nutrient cycling), and an increasing rate of invasion by non-native species. Thus, an increasing pace of anthropogenic ecological change has been a prominent trend in the Baltic Sea ecosystem since the Ancylus Lake.Future development is in the first place dependent on regional factors, such as salinity, which is regulated by sea and land level changes and the climate, and runoff, which controls both salinity and the leaching of nutrients to the sea. However, uncertainties abound, for example the future development of the Gulf Stream and its associated westerly winds, which support the sub-boreal ecosystems, both terrestrial and aquatic, in the Baltic Sea area. Thus, extensive sophisticated, cross-disciplinary modeling is needed to foresee whether the Baltic Sea will develop toward a freshwater or marine ecosystem, set in a sub-boreal, boreal, or arctic climate.
Book chapters on the topic "Turbid freshwaters"
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Dokulil, M. T., and J. Padisâk. "Long-term compositional response of phytoplankton in a shallow, turbid environment, Neusiedlersee (Austria/Hungary)." In Nutrient Dynamics and Biological Structure in Shallow Freshwater and Brackish Lakes, 125–37. Dordrecht: Springer Netherlands, 1994. http://dx.doi.org/10.1007/978-94-017-2460-9_11.
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De Sève, M. A. "Diatom bloom in the tidal freshwater zone of a turbid and shallow estuary, Rupert Bay (James Bay, Canada)." In Twelfth International Diatom Symposium, 225–33. Dordrecht: Springer Netherlands, 1993. http://dx.doi.org/10.1007/978-94-017-3622-0_24.
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"Historical Changes in Large River Fish Assemblages of the Americas." In Historical Changes in Large River Fish Assemblages of the Americas, edited by Bob Calamusso, John N. Rinne, and Robert J. Edwards. American Fisheries Society, 2005. http://dx.doi.org/10.47886/9781888569728.ch12.
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<em>Abstract.</em>—The Rio Grande is the fourth longest river in North America and the 22nd longest in the world. It begins as a cold headwater stream in Colorado, flows through New Mexico and Texas, where it becomes warm and turbid and finally empties into the Gulf of Mexico. The diversity of native fishes is high in the Rio Grande ranging from freshwater salmonids in its upper reaches to coastal forms in the lower reaches. Historically, about 40 primary freshwater species inhabited the waters of the Rio Grande. Like many rivers throughout North America, the native fish fauna of this river has been irrevocably altered. Species once present are now extinct, others are threatened or endangered, and the majority of the remaining native fishes are declining in both range and numbers. Today, 17 of the 40 primary native freshwater fishes have been either extirpated in part or throughout the Rio Grande drainage. This chapter examines the river, its fauna, and its current plight.
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"Historical Changes in Large River Fish Assemblages of the Americas." In Historical Changes in Large River Fish Assemblages of the Americas, edited by Bob Calamusso, John N. Rinne, and Robert J. Edwards. American Fisheries Society, 2005. http://dx.doi.org/10.47886/9781888569728.ch12.
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<em>Abstract.</em>—The Rio Grande is the fourth longest river in North America and the 22nd longest in the world. It begins as a cold headwater stream in Colorado, flows through New Mexico and Texas, where it becomes warm and turbid and finally empties into the Gulf of Mexico. The diversity of native fishes is high in the Rio Grande ranging from freshwater salmonids in its upper reaches to coastal forms in the lower reaches. Historically, about 40 primary freshwater species inhabited the waters of the Rio Grande. Like many rivers throughout North America, the native fish fauna of this river has been irrevocably altered. Species once present are now extinct, others are threatened or endangered, and the majority of the remaining native fishes are declining in both range and numbers. Today, 17 of the 40 primary native freshwater fishes have been either extirpated in part or throughout the Rio Grande drainage. This chapter examines the river, its fauna, and its current plight.
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"Challenges for Diadromous Fishes in a Dynamic Global Environment." In Challenges for Diadromous Fishes in a Dynamic Global Environment, edited by Rob MacGregor, John M. Casselman, William A. Allen, Tim Haxton, John M. Dettmers, Alastair Mathers, Steve LaPan, and Thomas C. Pratt. American Fisheries Society, 2009. http://dx.doi.org/10.47886/9781934874080.ch45.
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<em>Abstract</em>.-We examine historical, archaeological, and current patterns in American eel <em>Anguilla rostrata </em>use, abundance, and distribution to improve understanding of current population- level status. Our research indicates that distribution and abundance has changed significantly in response to the cumulative impacts of fishing, turbine mortality, and major loss of freshwater habitat. The 1950-1970 peaks in dam construction and turbine mortalities, together with the unprecedented North American harvests in the 1970s, have lead to a perilous synergy of effects at the population level. Based on our findings, we call for coordinated conservation and management actions for American eel across North America. Preservation of life cycle diversity and coordinated conservation actions are required across the range to ensure continued and improved societal benefits, protect the legacy of cultural and natural heritage values, restore ecological services, and reinstate the benefits to biodiversity provided by this unique and important species. Finally, we describe key elements and recent progress in recovery planning.
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Abulafia, David. "The Lighthouse of the Mediterranean, 350 BC–100 BC." In The Great Sea. Oxford University Press, 2011. http://dx.doi.org/10.1093/oso/9780195323344.003.0018.
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In 333 BC Alexander III, king of Macedon, whose claims to Greekness were treated with some scepticism down in Athens, wreaked vengeance on the Persian kings who had posed such a threat to Greece in past centuries, by defeating a massive Persian army at the battle of the Issos, beyond the Cilician Gates. Yet he did not pursue the Persian king, Darius III, into the Persian heartlands. He well understood the need to neutralize Persian power along the shores of the Mediterranean, and marched south through Syria and Palestine, where he ruthlessly took charge of the Phoenician cities that had in the past provided Persia with its fleets; Tyre resisted him for seven months, much to his fury, even after he built the great mole that for ever after joined the island city to the mainland. Once he had captured Tyre, most of its inhabitants were slaughtered, enslaved or crucified. He bypassed Jerusalem, choosing the road through Gaza, since his real target at this stage was Egypt, ruled by a Persian satrap for nearly 200 years, since the days of Cambyses, and his conquest of this land transformed not just Egypt but the entire eastern Mediterranean. The result of his victory was that Egypt was turned around, looking outwards to the Mediterranean rather than inwards to the Nile valley. In 331 BC he decided to found a city on the northernmost edge of Egypt, on a limestone spur separated from the alluvial lands of the interior by a freshwater lake – a city next to rather than actually in Egypt, as its designation in later Latin documents as Alexandria ad Aegyptum, ‘Alexandria on the way to [or ‘next to’] Egypt’, affirms. This sense that Alexandria was more a city of the Mediterranean than of Egypt would persist for over two millennia, until the expulsion of its foreign communities in the twentieth century. For much of that period it was the greatest city in the Mediterranean. Alexander’s motives certainly included his own glorification.
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Levy, Sharon. "Fighting the Big Sewage Machine." In The Marsh Builders. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780190246402.003.0010.
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Salmon were George Allen’s passion. He spent his professional life seeking to combine salmon restoration with sewage recycling, a mission as daunting as the upstream struggle of a weary chinook blocked by a dam. Salmon begin their lives as eggs buried in a gravel nest on a stream bottom, from which tiny fish emerge, swim to the surface, and start to feed. The young grow, lose their infant stripes, and swim to sea, steered by instinct and a physical drive to reach salt water. They range through the ocean for two years or more, growing into magnificent creatures. When the time is right, they return to their home streams to spawn. Crowds of wild, abundant salmon once fought their way up the rivers of the Pacific coast from central California to Alaska. The cycle was eternal, with no distinct beginning or end, until white civilization blocked the rivers with dams and smothered the spawning grounds in silt. By the time Allen came to teach fisheries at Humboldt State, in 1957, salmon runs all along the west coast were depleted. Most of the ancient stocks that had once populated the streams feeding Humboldt Bay were extinct. In an obscure corner of Arcata’s treatment plant, Allen and his students raised young coho and chinook in treated sewage flowing out of the city’s oxidation ponds. Soon after he arrived in Humboldt, Allen had begun planning to resurrect the bay’s lost salmon stocks, and Arcata’s sewage oxidation ponds proved the only likely spot to launch his quest. The oxidation ponds were a constant source of fresh water, with access to a stream, Jolly Giant Creek, which formed a small estuary where he could release fish to the bay. He took fingerlings from any hatchery that had extras and raised them to the moment of smoltification, when they lost their baby stripes, turned shiny silver, and transformed from freshwater to saltwater creatures. His intense hope was that they’d go to sea and return as adults, making the city’s wastewater plant the center of a salmon revival in Humboldt Bay.
Conference papers on the topic "Turbid freshwaters"
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Montes-Sánchez, J., B. de Weert, B. Petit, L. García-Rodríguez, and D. Sánchez. "Potential of Micro Gas Turbines to Provide Renewable Heat and Power in Off-Grid Applications for Desalination and Industrial Wastewater Treatment." In ASME Turbo Expo 2021: Turbomachinery Technical Conference and Exposition. American Society of Mechanical Engineers, 2021. http://dx.doi.org/10.1115/gt2021-60253.
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Abstract The demand for all types of resources (food, freshwater, energy and raw materials) has increased alarmingly due to the continuous techno-economic development of society, bringing about a pressing shortage not only in low-income countries but also in more developed economies. Such is the case for the very wealthy countries in the Gulf Cooperation Council, which are currently struggling with the lack of fresh water supply, or certain countries in Latin America where the contamination of natural water sources poses a major environmental threat. In order to assess this water-energy nexus problem, this paper looks into systems where the production of renewable power is combined with either freshwater production (through desalination) or industrial wastewater treatment for effluent control. Three enabling renewable energy technologies are assessed: solar micro gas turbines, wind turbines and photovoltaic panels. In all cases, off-grid installations are considered. The paper describes the characteristics of these three systems and provides a comparison of technical specifications, yield and costs. Wind and photovoltaic are the standard approach, as already proven by a number of commercial plants, but solar micro gas turbines exhibit additional flexibility (in particular when hybridisation is considered) and have the differential feature of producing not only electric power but also heat. This enables the combination of different types of water treatment technologies in order to increase water production/recovery which, in turn, reduces the environmental impact of the production process associated (either freshwater or other good or service).
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Alharbi, Sattam, Mohamed L. Elsayed, and Louis C. Chow. "ENERGY AND EXERGY ANALYSIS OF A NEW COMBINED SYSTEM FOR POWER, COOLING, HEATING AND FRESHWATER PRODUCTION BASED ON GAS TURBINE." In 5-6th Thermal and Fluids Engineering Conference (TFEC). Connecticut: Begellhouse, 2021. http://dx.doi.org/10.1615/tfec2021.ens.032430.
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Bandhauer, Todd M., and Shane D. Garland. "Dry Air Turbo-Compression Cooling." In ASME 2016 Power Conference collocated with the ASME 2016 10th International Conference on Energy Sustainability and the ASME 2016 14th International Conference on Fuel Cell Science, Engineering and Technology. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/power2016-59152.
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Electric power plants in the U.S. dissipate 4.3 billion gallons of water per day into the atmosphere through evaporative cooling. As freshwater resources become constrained, it will be essential for power plants to transition from evaporative cooling to dry air cooling. One of the major problems associated with dry air cooling is the large size and associated cost of the dry air heat exchangers due to the large surface area required to overcome the low convective heat transfer coefficient of air. This study investigates using low-grade waste heat available in the combustion exhaust gases (106°C inlet, 86 MW dry waste heat available) of a 565 MW Natural Gas Combined Cycle Power Plant (NGCC) to drive a supplemental high efficiency turbo-compression cooling (TCC) system that decreases the size of the dry air heat exchangers. In this system, both a recuperative Rankine cycle and a supercritical system were considered to drive a turbo-compressor. The low-grade waste heat is supplied to a flue gas heat exchanger in either the recuperative Rankine or supercritical cycle to generate power that drives a vapor compression cycle to supply supplementary cooling for the power plant condenser water. For the TCC system to operate at a high COP, both the turbine and compressor must operate at isentropic efficiencies exceeding 80%. This high efficiency has been demonstrated for centrifugal turbomachines for a wide variety of applications over small ranges of specific speed: from 45 to 100 for turbines, and from 80 to 140 for compressors. In the present study, a wide range of possible fluids was considered to perform a complete system level thermodynamic analysis combined with a turbo-compressor dimensional scaling analysis. The results of the analyses show that the total UA required for both the primary dry air coolers and the dry air condensers in the supercritical TCC system with a COP of 2 is 26% less than the UA required for dry air cooling alone (from 150.7 to 111.5 MW K−1). As a result, using the supercritical TCC cooling system has the potential to reduce the overall cost of dry air cooling relative to the state of the art.
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Akram, Waqas, and Mostafa H. Sharqawy. "Power Generation With Pressure Retarded Osmosis." In ASME 2013 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2013. http://dx.doi.org/10.1115/imece2013-66590.
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Energy can be generated from two streams of different salt concentration using the osmotic pressure difference. Different methods have been proposed to harvest this energy. Pressure retarded osmosis (PRO) is investigated as a viable method and most promising technology. In PRO process, pure water permeates through a semi permeable membrane from the low hydrostatic pressure stream (feed solution) to the higher hydrostatic pressure stream (draw solution) due to the osmotic pressure difference. This increases the volume flow rate of the pressurized draw stream and energy is obtained by depressurizing the draw stream through a hydro turbine. In this study a one-dimensional computational model is developed to precisely estimate the power production under different operating conditions. Different feed and draw solution concentrations are used to estimate the power production from PRO. The maximum power density (power per unit membrane area), using available membrane characteristics, obtained from seawater–freshwater streams is 2.6 W/m2 and for the disposed brine–seawater streams is 9.1 W/m2. The performance of PRO process is very sensitive to the membrane characteristics in particular to the water permeability and PRO module configuration.
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Nicoll, Ryan S., Charles F. Wood, and André R. Roy. "Comparison of Physical Model Tests With a Time Domain Simulation Model of a Wave Energy Converter." In ASME 2012 31st International Conference on Ocean, Offshore and Arctic Engineering. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/omae2012-83699.
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Development of wave energy conversion systems may yield many key benefits for society such as the production of electrical power or fresh water for remote communities. However, complex ocean dynamics make it difficult for technology developers to not only address the stability and survivability of their systems, but also to establish energy conversion rates that are fundamental to proving economic viability. Building physical prototypes presents many challenges in terms of cost, accessible facilities, and time requirements. The use of accurate numerical modelling and computer simulation can help guide design and significantly reduce the number of physical prototype tests required and as a result play a primary role in the development of wave energy conversion systems that have to operate in challenging marine environments. SurfPower is an ocean wave energy converter (WEC) that converts wave motion into useful energy through surge and heave motion of a point absorber. The system pumps seawater into a high pressure hydraulic network that generates electricity via a turbine or freshwater via desalination at a facility onshore. The system is nonlinear due to the significant change in draft and mooring reaction load through the energy capture cycle of the device. This makes the use of nonlinear time domain simulation ideal for analysis and design of the system. Furthermore, utilizing a simplified nonlinear hydrodynamic model available in the time domain results in a practical early-stage design tool for system refinement. The focus of this work is to compare the results of scale model testing completed at the Institute for Ocean Technology in St. John’s, Newfoundland, with results produced from an equivalent system simulated in the time domain simulation software ProteusDS. The results give an assessment of the range of error that can be used to assess other experiments of the SurfPower WEC at full scale.