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1
MORKOYUNLU YUCE, Arzu, Arif GÖNÜLOL e Şebnem ERKEBAY. "Trophic Status Assessment In Some Lotic Ecosystem In Turkey (Sakarya Basin)". Journal of the Institute of Science and Technology 13, n. 3 (26 aprile 2023): 2162–73. http://dx.doi.org/10.21597/jist.1173729.
Testo completoAbstract (sommario):
Benthic diatoms constitute a very important group of organisms in terms of providing information about the water quality of the lotic ecosystems. This research was carried out in Istanbul creek, Aliaga creek, Bostancı creek and Orta creek in the Sakarya basin. The trophic states of these creeks were evaluated according to their diatomes. In the study, the epilithic diatoms were determined to consist of 42 taxa belonging to İstanbul creek, 28 to Bostancı creek, 25 to Orta creek and 20 to Aliaga creek. A total of 51 taxa were determined in the creeks. In this study, Cocconeis pediculus, Ulnaria ulna and Cymbella affinis were found to have the highest abundant at the stations. In the creeks, water temperature, dissolved oxygen and pH were determined as respectively 9.1-14.1 ℃, 8.2-9.4 mg L-1, 7.1- 7.5 and conductivity as 210.2 - 240.4 μS cm-1. Although different results were obtained according to the diatom indices criteria (IBD, SLA,IDSE,IDAP, TID, SID,CEE, WAT, TDI, SHE, TIT) the creeks were determined to be close to water quality class I -II according to the Surface Water Quality Regulation In general, according to the diatom index values, it has been determined that the creeks have good-medium quality water characteristics.
2
Greer, Richard, Peter McGowan, Jacqueline Michel e Norman Meade. "INJURY TO MUSKRATS (ONDATRA ZIBETHICUS) FROM THE CHALK POINT OIL SPILL, PATUXENT RIVER, MARYLAND1". International Oil Spill Conference Proceedings 2005, n. 1 (1 maggio 2005): 787–91. http://dx.doi.org/10.7901/2169-3358-2005-1-787.
Testo completoAbstract (sommario):
ABSTRACT Spill-associated mortality from the Chalk Point oil spill to muskrats (Ondatra zibethicus) was estimated using habitat and oiling extent data, muskrat population and home range estimates, local expert opinion, and hut count indices for three impacted creeks. Most of the 70 dead muskrats were collected from Swanson Creek. Muskrat density in this creek was estimated by local experts, and extrapolation from densities reported at a nearby wildlife refuge. Muskrat habitat acreage within Swanson Creek was determined using digitized aerial photography. Acreages of oiled marsh habitat for Swanson, Indian, and Trent Hall Creeks were estimated using spatial analysis. Oiling of muskrats likely occurred to those whose home ranges overlapped the spill area. Radius of a muskrat home range was reported to be 30 meters, and 30 meter buffers were circumscribed along borders of the oiled areas for these creeks. Exposure zone acreages were determined by summing the 30-meter buffers and oiled areas for Swanson, Indian, and Trent Hall Creeks, totaling 75.02, 19.55, and 9.12 acres, respectively. Muskrat population exposure within Swanson Creek was estimated by multiplying exposure zone acreage by muskrat density (4.2 per acre), totaling 315 individuals. Muskrat populations for Indian and Trent Hall Creeks were quantified using hut count indices and comparisons to the count index and population estimate for Swanson Creek. Muskrat exposures in Indian and Trent Hall Creeks were determined by multiplying estimated muskrat density by the exposure zone acreage for each creek. The exposed population was calculated to be 32 and 29 for Indian Creek and Trent Hall Creek, respectively. Assuming 100% mortality for muskrats potentially exposed to oiled marsh habitat, the total acute mortality in the spill area was estimated to be 376 individuals (i.e., 315 in Swanson Creek, 32 in Indian Creek, and 29 in Trent Hall Creek). Total muskrat years lost are calculated, and the strengths and uncertainties of this approach are discussed.
3
Chen, Xu, Mingliang Zhang e Hengzhi Jiang. "Morphological Characteristics and Hydrological Connectivity Evaluation of Tidal Creeks in Coastal Wetlands". Land 11, n. 10 (1 ottobre 2022): 1707. http://dx.doi.org/10.3390/land11101707.
Testo completoAbstract (sommario):
Tidal creeks play a critical role in delivering water, suspended sediments, and nutrients to coastal wetlands, so it is important to understand the characteristics of the tidal creek system to guide the development and sustainable utilization of coastal wetlands. Using the coastal wetlands of the Liao River Estuary (LRE) as a study area, this study accurately divided the tidal flat based on the principle of tidal correction, extracted the linear features of tidal creeks using high-resolution remote sensing (RS) data, and then classified the tidal creeks on a tidal flat using the tidal creek ordering algorithm. Our study aimed to quantify the morphological characteristics of tidal creeks and qualitatively evaluate the parameters of the tidal creek network in the study area. The study results show obvious spatial heterogeneity in the order and the average length of tidal creeks in the coastal wetlands of the LRE. With the increase in the order of tidal creeks, the average length of tidal creeks increased exponentially and the number of tidal creeks decreased exponentially in the study area. The total density of tidal creeks was related to the beach surface elevation gradient, and the density and frequency of tidal creeks reduced substantially with an increase in the order of tidal creeks. The sinuosity ratio of tidal creeks declined sharply with a fall in the beach surface elevation gradient. The average bifurcation ratio of tidal creeks in the upper intertidal zone was higher than that in other zones, indicating that the tidal creeks in the upper intertidal zone were erratic. In addition, the hydrological connectivity of the tidal creek network in the upper intertidal zone and the development of the tidal creek system in the supratidal zone were the highest in the LRE. The study results help understand the spatial variations in tidal creek morphology under the influence of tidal hydrodynamics.
4
Chow-Fraser, Patricia, Barb Crosbie, Douglas Bryant e Brian McCarry. "Potential Contribution of Nutrients and Polycyclic Aromatic Hydrocarbons from the Creeks of Cootes Paradise Marsh". Water Quality Research Journal 31, n. 3 (1 agosto 1996): 485–504. http://dx.doi.org/10.2166/wqrj.1996.028.
Testo completoAbstract (sommario):
Abstract During the summer of 1994, we compared the physical and nutrient characteristics of the three main tributaries of Cootes Paradise: Spencer, Chedoke and Borer’s creeks. On all sampling occasions, concentrations of CHL α and nutrients were always lowest in Borer’s Creek and highest in Chedoke Creek. There were generally 10-fold higher CHL α concentrations and 2 to 10 times higher levels of nitrogen and phosphorus in Chedoke Creek compared with Spencer Creek. Despite this, the light environment did not differ significantly between Spencer and Chedoke creeks because the low algal biomass in Spencer Creek was balanced by a relatively high loading of inorganic sediments from the watershed. Laboratory experiments indicated that sediments from Chedoke Creek released up to 10 µg/g of soluble phosphorus per gram (dry weight) of sediment, compared with only 2 µg/g from Spencer Creek. By contrast, sediment samples from Spencer Creek contained levels of polycyclic aromatic hydrocarbon that were as high as or higher than those from Chedoke Creek, and much higher than those found in Borer’s Creek. The distribution of normalized PAH concentrations suggests a common source of PAHs in all three tributaries, most likely automobile exhaust, since there were high concentrations of fluoranthene and pyrene, both of which are derivatives of engine combustion.
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Vo, Phuoc Luong Hong, e Phuc Tran Duy Le. "TIDAL ASYMMETRY IN MANGROVE CREEKS". Science and Technology Development Journal 14, n. 4 (30 dicembre 2011): 86–92. http://dx.doi.org/10.32508/stdj.v14i4.2030.
Testo completoAbstract (sommario):
A simple analytical model for flow in the creeks is formulated, built up and applied in the real conditions in Nang Hai creek, Can Gio mangrove Biosphere Reserve (Ho Chi Minh city).Observed data of current speed and water level in the creek in the year of 2005 were used to find the friction coefficients in the mangrove swamp and to apply in the model. Results from calculated modeling show obviously the tidal asymmetry in mangrove creek. The peaks of current speed at flood and ebb tides are not equal as the swamp is inundated. The friction coefficients have the great influence in the tidal asymmetry. The friction coefficient in the creek can change remarkably the current speed in the creek, inducing the changes of the current speed peaks. The friction coefficient in the swamp has much less influenced to the current speed in the creeks.
6
Valiñas, Macarena, Eduardo M. Acha e Oscar Iribarne. "Habitat use and feeding habits of juvenile fishes in an infrequently flooded Atlantic saltmarsh". Marine and Freshwater Research 61, n. 10 (2010): 1154. http://dx.doi.org/10.1071/mf09109.
Testo completoAbstract (sommario):
In saltmarshes, marsh creeks provide an important corridor between the marsh and the subtidal habitat for fishes. We compare fish and prey in a Spartina densiflora marsh creek with a tidal flat in the SW Atlantic (Argentina) to evaluate the hypotheses that: (1) benthic prey abundance is higher in the marsh creek, and therefore the abundance of benthivorous fishes and predation pressure on benthos is higher in this area; and (2) marsh creeks act as refuge areas for fishes. Fish abundance and benthic prey availability were sampled over four seasons, and dietary composition of Odontesthes argentinensis and Micropogonias furnieri was assessed. Brevoortia aurea was more abundant in the marsh creek, Micropogonias furnieri showed the opposite pattern, and Odontesthes argentinensis and Ramnogaster arcuata did not dominate either habitat. As expected, smaller fishes were more abundant in the marsh creek. Food abundance was higher in the marsh creek but only M. furnieri consumed more prey in this area, while O. argentinensis consumed more in the tidal flat. Differences in prey accessibility and sediment features between areas could explain these results. This work highlights the importance of marsh creeks as refuge and/or feeding grounds for fishes in infrequently flooded saltmarshes.
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Gu, Bon-Ho, Seung-Buhm Woo, Jae-Il Kwon, Sung-Hwan Park e Nam-Hoon Kim. "Case Study of Contaminant Transport Using Lagrangian Particle Tracking Model in a Macro-Tidal Estuary". Water 16, n. 4 (19 febbraio 2024): 617. http://dx.doi.org/10.3390/w16040617.
Testo completoAbstract (sommario):
This study presents a comprehensive analysis of contaminant transport in estuarine environments, focusing on the impact of tidal creeks and flats. The research employs advanced hydrodynamic models with irregular grid systems and conducts a detailed residual current analysis to explore how these physical features influence the movement and dispersion of contaminants. The methodology involves simulating residual currents and Lagrangian particle trajectories in both ‘Creek’ and ‘No Creek’ cases, under varying tidal conditions. The results indicate that tidal creeks significantly affect particle retention and transport, with notable differences observed in the dispersion patterns between the two scenarios. The ‘Creek’ case demonstrates enhanced material retention along the creek pathways, while the ‘No Creek’ case shows broader dispersion, potentially leading to increased sedimentation in open sea areas. The discussion highlights the implications of these findings for sediment dynamics, contaminant transport, and estuarine ecology, emphasizing the role of tidal creeks in modulating flow and material transport. The research underlines the necessity of incorporating detailed environmental features in estuarine models for accurate contaminant transport prediction and effective estuarine management. This study contributes to a deeper understanding of estuarine hydrodynamics and offers valuable insights for environmental policy and management in coastal regions.
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Magolan, Jessica Lynn, e Joanne Nancie Halls. "A Multi-Decadal Investigation of Tidal Creek Wetland Changes, Water Level Rise, and Ghost Forests". Remote Sensing 12, n. 7 (3 aprile 2020): 1141. http://dx.doi.org/10.3390/rs12071141.
Testo completoAbstract (sommario):
Coastal wetlands play a vital role in protecting coastlines, which makes the loss of forested and emergent wetlands devastating for vulnerable coastal communities. Tidal creeks are relatively small hydrologic areas that feed into larger estuaries, are on the front lines of the interface between saltwater and freshwater ecosystems, and are potentially the first areas to experience changes in sea level. The goal of this study was to investigate wetland changes through time at two tidal creeks (Smith Creek and Town Creek) of the Cape Fear River estuary in southeastern North Carolina, USA, to determine if there is a spatial relationship between habitat change, physical geography characteristics, and the rate of wetland migration upstream. Historic aerial photography and recent satellite imagery were used to map land cover and compute change through time and were compared with derived physical geography metrics (sinuosity, creek width, floodplain width, floodplain elevation, and creek slope). The primary results were: (1) there was a net gain in emergent wetlands even accounting for the area of wetlands that became water, (2) wetlands have migrated upstream at an increasing rate through time, (3) land cover change was significantly different between the two creeks (P = 0.01) where 14% (67.5 ha) of Smith Creek and 18% (272.3 ha) of Town Creek transitioned from forest to emergent wetland, and (4) the transition from emergent wetland to water was significantly related to average change in creek width, floodplain elevation, and average water level. In conclusion, this research correlated habitat change with rising water level and identified similarities and differences between neighboring tidal creeks. Future research could apply the methodologies developed here to other coastal locations to further explore the relationships between tides, sea level, land cover change, and physical geography characteristics.
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Che, Celestine A., Jeremy W. Pike, William C. Bridges e Joseph D. Culin. "Impacts on Larval Populations of Ephemeroptera, Plecoptera, and Trichoptera in Areas Infested by Hemlock Woolly Adelgid (Hemiptera: Adelgidae) at the Southern Edge of the Range of Eastern Hemlock". Journal of Entomological Science 57, n. 2 (29 marzo 2022): 156–72. http://dx.doi.org/10.18474/jes21-30.
Testo completoAbstract (sommario):
Abstract Eastern hemlock, Tsuga canadensis (L.) Carriere, is an important component of riparian zones in Appalachian forests. Tree mortality caused by hemlock woolly adelgid, Adelges tsugae Annand (Hemiptera: Adelgidae) could impact aquatic macroinvertebrate populations. Our study examined larval populations of Ephemeroptera, Plecoptera, and Trichoptera occurring in the headwaters of two creeks in the Sumter National Forest (Oconee Co., SC). Larval populations were initially sampled in King Creek (2006) and Crane Creek (2007) in separate studies. When those studies were conducted, there was no noticeable decline in hemlock health along either creek. However, by 2009 hemlock mortality along both creeks was obvious, and the Ephemeroptera, Plecoptera, and Trichoptera community was resurveyed on both creeks. This is the first study comparing aquatic macroinvertebrate populations before and after A. tsugae infestation. Ephemeroptera, Plecoptera, and Trichoptera larvae were identified to genus, and analyzed at the functional feeding group level. In both creeks, collector filterers and scrapers were significantly more abundant in the initial survey than in 2009. Generic diversity within each creek was examined using the total Ephemeroptera, Plecoptera and Trichoptera community, and was based on the indices of: richness (D0), Shannon exponential (D1), and inverse Simpson (D2). The only diversity measure that differed significantly between the original survey and 2009 was the Shannon exponential index for Crane Creek which was significantly higher in 2009 than 2006
10
Waweru, Beth Wangui, Charity Wangui Wanjohi, Agnes Wangui N. Muthumbi, Eric Ochieng Okuku e Nathan Ndegwa Gichuki. "Meiofauna as bioindicators of organic and inorganic pollution of estuarine sediments in Kenya". Western Indian Ocean Journal of Marine Science 23, n. 1 (31 maggio 2024): 69–80. http://dx.doi.org/10.4314/wiojms.v23i1.7.
Testo completoAbstract (sommario):
Meiofaunal density, diversity, and community assemblages were studied at the highly con- taminated Tudor Creek and the less contaminated Mida Creek in Kenya to assess their poten- tial as bioindicators of marine pollution. Sampling during the dry (January/February 2017) and wet (November/December 2017) seasons indicated a significantly greater total organic matter content at Mida (23.7 and 23.9 %) than at Tudor Creek (6.6 and 5.9 %) in the dry and wet seasons. Heavy metal concentrations were always greater at Tudor Creek. Meiofaunal densi- ties were greater at Mida (2729 and 2804 ind.10 cm-2) than Tudor Creek (612 and 183 ind.10 cm-2) during both seasons. Meiofauna at Mida Creek (10 and 7 taxa in the dry and wet seasons) were dominated by nematodes, copepods, and turbellarians. Meiofauna at Tudor Creek (8 and 6 taxa) were dominated by nematodes, turbellarians and ostracods. Meiofaunal diversity was greater at Tudor Creek, but dominance was highest at Mida Creek. Community dissimilarities between the two sites were shown in a Bray-Curtis cluster analysis. There is a high likelihood that heavy metals affect meiofauna density and diversity in the sediments of the two studied creeks in Kenya.
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Gutiérrez, Mélida, Xiaomin Qiu, Zachary J. Collette e Zachary T. Lurvey. "Metal Content of Stream Sediments as a Tool to Assess Remediation in an Area Recovering from Historic Mining Contamination". Minerals 10, n. 3 (8 marzo 2020): 247. http://dx.doi.org/10.3390/min10030247.
Testo completoAbstract (sommario):
Lead and zinc mining was booming in the early 1900s in and near Joplin, Missouri; a town within the Tri-State Mining District, USA. After the ore became depleted, mining companies moved out, leaving a profoundly disturbed land. Presently, over 90% of the land has been remediated. We collected sediment samples along two creeks flowing through the historically contaminated area that have been identified as major contributors of metals to downstream reservoirs, Center Creek (14 samples) and Turkey Creek (30 samples). Sediment metal content was determined by aqua regia extraction, the potentially bioavailable fraction by 0.11 M acetic acid extraction, and toxicity by ΣPEC-QCd,Pb,Zn. Zinc and lead content in sediments were high in both creeks notwithstanding remediation actions; e.g., median concentrations of 521 mg/kg Pb and 5425 mg/kg Zn in Center Creek, corresponding to 19 and 52 times the background concentration. The metals’ distribution followed no discernible pattern downstream. The potentially bioavailable fraction varied between 0.36% (Pb, Center Creek) and 4.96% (Zn, Turkey Creek). High toxicity was found in 40% of the samples in Turkey Creek and 78.5% of the samples in Center Creek. While this level of toxicity would likely affect aquatic organisms, its limited mobility under alkaline conditions suggests a lesser threat to humans. On the other hand, this high toxicity will likely persist in sediments for at least a few decades, based on their high metal content and low mobility.
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Thorburn, PJ, LJ Mensforth e GR Walker. "Reliance of creek-side river red gums on creek water". Marine and Freshwater Research 45, n. 8 (1994): 1439. http://dx.doi.org/10.1071/mf9941439.
Testo completoAbstract (sommario):
Measurements of naturally occurring stable isotopes of hydrogen (2H) and oxygen (18O) were used to determine the importance of creek waters to river red gums (Eucalyptus camaldulensis Dehnh., Myrtaceae) on the banks of creeks in the semi-arid and saline Chowilla floodplain region of South Australia. The 2H and 18O concentrations of water sampled from trees were significantly different from those of the creek water, indicating that, generally, trees were not obtaining all their water from the creek. This was found even in trees overlying highly saline groundwater. Thus, saline groundwater and/or soil water were important water sources for the trees studied. The results indicated that the water relations of these trees are complex, and the trees may be less affected by changes in creek flow and/or salinity than was previously anticipated.
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I. CHRİS, Davies, e Efekemo OGEHENETEKEVWE. "Impact of Artisanal Crude Oil Refining Effluents on Interstitial Water at a Mangrove Wetland, Asari-Toru Axis of Sombreiro River, Rivers State." International Journal of Environment and Geoinformatics 10, n. 2 (15 giugno 2023): 12–23. http://dx.doi.org/10.30897/ijegeo.1132992.
Testo completoAbstract (sommario):
A comparative study on the water quality of the interstitial water of two creeks in Rivers State was conducted. Temperature, pH, Conductivity, Dissolved oxygen, biochemical oxygen demand, Salinity, and Total dissolved solid were checked with an in-situ hand-held multi-meter (The EZODO Multi-meter). Dissolved oxygen (DO) was measured with a Milwaukee Dissolved oxygen meter while Biochemical Oxygen Demand (BOD) was determined by the 5-day BOD test (APHA, 2005). The temperature ranged between 28.3 to 29.3℃ in the Opro-ama creek and 26.0 -26.8℃ in Buguma creek. The pH value ranged from 6.2 to 6.8 in Opro-ama creek while that of Sa-ama creek was between 6.8 and 6.99. Salinity ranges from 9.1 to 9.5 (ppt) in the Opro-ama creek while Sa-ama creek recorded a range between 11.2 to 12.0 (ppt). The dissolved oxygen was between 1.5 and 2.3 (µS/cm) in Okpoka creek meanwhile Sa-ama creek varied between 4.6 and 4.10 (µS/cm). The biochemical oxygen demand values were between 1.4 to 2.3 (µS/cm) in Opro-ama creek while that of Sa-ama was between 1.9 to 2.4 (µS/cm). The conductivity values for the Opro-ama creek were between 10.3 and 10.6 while Sa-ama creek recorded a value of 12.5 to12.6 (µS/cm). there were significant variations (P
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Man, Ying, Fangwen Zhou e Baoshan Cui. "Process–Based Identification of Key Tidal Creeks Influenced by Reclamation Activities". Sustainability 15, n. 10 (17 maggio 2023): 8123. http://dx.doi.org/10.3390/su15108123.
Testo completoAbstract (sommario):
Reclamation activities constitute a major factor threatening tidal creeks, which play an important role in the health of the ecosystem of deltas. Research on the influence of reclamation activities on the connectivity of tidal creeks is often based on changes in their morphology and ignores the process that shapes this morphology. Instead, the authors of this study focus on the influence of reclamation activities on hydrological connectivity inside the tidal creek from a process-based perspective. Changes in the hydrological distances that reflect the relative movement of sites in each tidal creek are identified and related to the resistance surface (a spatial layer that assigns values to features of the landscape, indicating the degree to which these features impede or promote movement) of the reclamation activities. We also objectively quantify the influence of different reclamation activities on the connectivity of the tidal creek. We used the proposed method to identify changes in key tidal creeks in the Yellow River Delta under the influence of reclamation activities. The results revealed the potential influence of reclamation activities (before changes appeared in the morphology of the tidal creek) from 1990 to 1995. The use of resistance surfaces thus provides a comprehensive understanding of the interactions between reclamation activities and the connectivity of tidal creeks.
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Smith, Christian T., Stewart B. Reid, Lindsay Godfrey e William R. Ardren. "Gene Flow Among Modoc Sucker and Sacramento Sucker Populations in the Upper Pit River, California and Oregon". Journal of Fish and Wildlife Management 2, n. 1 (1 giugno 2011): 72–84. http://dx.doi.org/10.3996/022010-jfwm-003.
Testo completoAbstract (sommario):
Abstract The Modoc sucker Catostomus microps received legal protection in the United States based partially on concerns that anthropogenic environmental changes had restricted migration among populations and catalyzed hybridization with a more abundant congener, the Sacramento sucker Catostomus occidentalis. We applied eight microsatellite markers to samples of both species collected from two tributaries to the Pit River, California (Ash Creek and Turner Creek), and one tributary of Goose Lake, Oregon (Thomas Creek). Modoc sucker populations in these three tributaries seemed to be largely isolated from one another: gene flow between Ash Creek and Turner Creek was no greater than that among these two creeks and Thomas Creek. In contrast, divergence estimates among collections of Sacramento suckers indicated greater gene flow between Ash Creek and Turner Creek than between either of these creeks and Thomas Creek. Samples collected at a single site (Ash Valley) were identified based on morphology as Modoc suckers, but genetic data suggested they were much more similar to Sacramento suckers. Interspecific hybrids were detected in all three tributaries. Collections of Modoc suckers yielded 0.0–3.9% hybrids, and collections of Sacramento suckers yielded 0.0–80.0% hybrids. The two collections with the greatest proportions of hybrids (54.5 and 80.0%) were both from tributaries to lower Thomas Creek, and neither of these tributaries is thought to have upstream populations of Modoc suckers. Based on 1) low levels of hybrid detection in all three tributaries, 2) the absence of hybrids from typical parental habitats (upstream habitats for Modoc suckers and Pit River mainstem for Sacramento suckers), and 3) highly significant RST (variance in allele size) values between the species, we conclude that hybridization is common but that significant introgression (i.e., loss of parental genotypes) has not occurred. We also note that hybridization, and subsequent introgression, may become a conservation concern in such cases when the habitat of one or both of these species is eliminated or modified.
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Bost, Molly C., Charles D. Deaton, Antonio B. Rodriguez, Brent A. McKee, F. Joel Fodrie e Carson B. Miller. "Anthropogenic impacts on tidal creek sedimentation since 1900". PLOS ONE 18, n. 1 (18 gennaio 2023): e0280490. http://dx.doi.org/10.1371/journal.pone.0280490.
Testo completoAbstract (sommario):
Land cover and use around the margins of estuaries has shifted since 1950 at many sites in North America due to development pressures from higher population densities. Small coastal watersheds are ubiquitous along estuarine margins and most of this coastal land-cover change occurred in these tidal creek watersheds. A change in land cover could modify the contribution of sediments from tidal creek watersheds to downstream areas and affect estuarine habitats that rely on sediments to persist or are adversely impacted by sediment loading. The resilience of wetlands to accelerating relative sea-level rise depends, in part, on the supply of lithogenic sediment to support accretion and maintain elevation; however, subtidal habitats such as oyster reefs and seagrass beds are stressed under conditions of high turbidity and sedimentation. Here we compare sediment accumulation rates before and after 1950 using 210Pb in 12 tidal creeks across two distinct regions in North Carolina, one region of low relief tidal-creek watersheds where land cover change since 1959 was dominated by fluctuations in forest, silviculture, and agriculture, and another region of relatively high relief tidal-creek watersheds where land-use change was dominated by increasing suburban development. At eight of the creeks, mass accumulation rates (g cm-2 y-1) measured at the outlet of the creeks increased contemporaneously with the largest shift in land cover, within the resolution of the land-cover data set (~5-years). All but two creek sites experienced a doubling or more in sediment accumulation rates (cm yr-1) after 1950 and most sites experienced sediment accumulation rates that exceeded the rate of local relative sea-level rise, suggesting that there is an excess of sediment being delivered to these tidal creeks and that they may slowly be infilling. After 1950, land cover within one creek watershed changed little, as did mass accumulation rates at the coring location, and another creek coring site did not record an increase in mass accumulation rates at the creek outlet despite a massive increase in development in the watershed that included the construction of retention ponds. These abundant tidal-creek watersheds have little relief, area, and flow, but they are impacted by changes in land cover more, in terms of percent area, than their larger riverine counterparts, and down-stream areas are highly connected to their associated watersheds. This work expands the scientific understanding of connectivity between lower coastal plain watersheds and estuaries and provides important information for coastal zone managers seeking to balance development pressures and environmental protections.
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Brinton, Cameron Patrick, e Mary Carla Curran. "Tidal and diel movement patterns of the Atlantic stingray (Dasyatis sabina) along a stream-order gradient". Marine and Freshwater Research 68, n. 9 (2017): 1716. http://dx.doi.org/10.1071/mf16073.
Testo completoAbstract (sommario):
The behaviour of the Atlantic stingray (Dasyatis sabina) is affected by environmental cues, including time of day and tide. The purpose of the present study was to determine whether these cycles and differences in creek geomorphology affected presence and movement patterns of Atlantic stingrays near Savannah, GA, USA. Forty-five stingrays were tagged with Vemco coded-acoustic transmitters and passively tracked in two creek systems between December 2012 and December 2014. The geomorphology of the creeks was classified using the Horton stream-order concept, with the smallest tributaries assigned to the first order. Stingrays moved most at dusk (0.26±0.09 movements day–1), followed by night (0.23±0.09 movements day–1). Stingrays were found in deeper water during the cold season than during the warm season. Patterns in creek usage across tidal stages were nearly consistent across seasons. However, the diel pattern varied; stingrays utilised all creek orders throughout the diel cycle in the warm seasons, but entered only shallow creeks during the day in the cold season. Because presence and movements of stingrays were affected by tidal and diel cycles, these environmental factors could also affect their foraging patterns and their influence as an ecosystem engineer.
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Ellis, Kathryn K., Timothy Callahan, Dianne I. Greenfield, Denise Sanger, Joshua Robinson e Martin Jones. "Measuring and Modeling Flow Rates in Tidal Creeks: A Case Study from the Central Coast of South Carolina". Journal of South Carolina Water Resources, n. 4 (1 giugno 2017): 21–39. http://dx.doi.org/10.34068/jscwr.04.03.
Testo completoAbstract (sommario):
The purpose of this study was to collect site- and condition-specific hydrology data to better understand the water flow dynamics of tidal creeks and terrestrial runoff from surrounding watersheds. In this paper, we developed mathematical models of tidal creek flow (discharge) in relation to time during a tidal cycle and also estimated terrestrial runoff volume from design storms to compare to tidal creek volumes. Currently, limited data are available about how discharge in tidal creeks behaves as a function of stage or the time of tide (i.e., rising or falling tide) for estuaries in the southeastern United States, so this information fills an existing knowledge gap. Ultimately, findings from this study will be used to inform managers about numeric nutrient criteria (nitrogen-N and phosphorus-P) when it is combined with biological response (e.g., phytoplankton assemblages) data from a concurrent study. We studied four tidal creek sites, two in the Ashepoo-Combahee-Edisto (ACE) Basin and two in the Charleston Harbor system. We used ArcGIS to delineate two different watersheds for each study site, to classify the surrounding land cover using the NOAA Coastal Change Analysis Program (C-CAP) data, and to analyze the soils using the NRCS Soil Survey Geographic database (SSURGO). The size of the U.S. Geological Survey’s Elevation Derivatives for National Application (EDNA) watersheds varied from 778 to 2,582 ha; smaller geographic watersheds were delineated for all sites (except Wimbee) for stormwater modeling purposes. The two sites in Charleston Harbor were within the first-order Horlbeck Creek and the second-order Bulls Creek areas. The ACE Basin sites were within the third-order Big Bay Creek and the fourth-order Wimbee Creek areas. We measured the stage and discharge in each creek with an acoustic Doppler current profiler (ADCP) unit for multiple tide conditions over a 2-year period (2015–2016) with the goal of encompassing as large of a range of tide stage and discharge data measurements as possible. The Stormwater Runoff Modeling System (SWARM) was also used to estimate the potential water entering the creeks from the land surface; this volume was very small relative to the tide water volume except for the more-developed Bulls Creek watershed. The results show that the peak discharge occurred on the ebb tide and that the duration of the flood tide spanned a longer period of time; both of these observations are consistent with traits associated with an ebb-dominated tidal creek system. The tidal inflow and outflow (flood and ebb tides, respectively) showed an asymmetrical pattern with respect to stage and discharge; peak discharge during the flood (rising) tide occurred at a higher stage than for the peak discharge during the ebb (falling) tide. This is not an unexpected result, as the water on an ebb tide is moving down gradient funneled through the creek channel toward the coast. Furthermore, water moving with the rising flood tide must overcome frictional losses due to the marsh bank and vegetation; i.e., the peak discharge can only happen when the water has risen above these impediments. We infer from the flow dynamics data that faster water velocities during ebb tide imply that more erosive energy could transport a larger mass of suspended solids and associated nutrients (e.g., orthophosphate) from the estuary to the coastal ocean. However, the discharge and runoff modeling indicate that land-based flux was important in the developed Bulls Creek watershed, but not at the larger and less-developed Big Bay Creek watershed. At Big Bay Creek, the relatively large tidal discharge volume compared to the smaller potential runoff generated within the watershed indicates that the creek could potentially dilute terrestrial runoff contaminants. Smaller, more-urbanized tidal wetland systems may not benefit from such dilution effects and thus are vulnerable to increased runoff from adjacent developed landscapes.
19
Pimentell, Emily M. "OIL SPILL CLEANUP AND HABITAT RESTORATION—LITTLE PANOCHE CREEK, CALIFORNIA1". International Oil Spill Conference Proceedings 1985, n. 1 (1 febbraio 1985): 331–34. http://dx.doi.org/10.7901/2169-3358-1985-1-331.
Testo completoAbstract (sommario):
ABSTRACT In September 1983, an underground pipeline break resulted in a 31,000 barrel crude oil spill into Little Panoche Creek, Fresno County, California. The crude oil spill saturated soil and vegetation for two miles along the creek. Although the creek in itself is not of significant economic or environmental importance, the collective protection of creeks in the area is important. Water is a limiting resource and wildlife habitats have been minimized due to agricultural development. The goal of the cleanup was to completely remove contaminated soil and vegetation so as to minimize direct damage to wildlife including the San Joaquin Kit Fox, a state-listed rare species and federally-listed endangered species. Mitigation measures included the construction of small water ponding areas to enhance the growth of existing marsh vegetation, and seeding to revegetate the creek banks with indigenous shrubs to provide cover for wildlife and minimize soil erosion. Although a large volume of oil was spilled, conditions such as slow water flow in the creek, easy equipment access to the creek, and a natural oil collection area provided for favorable cleanup conditions and resulted in 99 percent recovery of oil. Contaminated soil was stockpiled to allow it to biodegrade, rather than use the costly alternative of landfill disposal. The creek habitat was near full recovery one year after the spill. Recovery was assessed by the regrowth of marsh and shrub vegetation in the creek and its adjacent banks.
20
Trott, L. A., e D. M. Alongi. "Variability in surface water chemistry and phytoplankton biomass in two tropical, tidally dominated mangrove creeks". Marine and Freshwater Research 50, n. 5 (1999): 451. http://dx.doi.org/10.1071/mf98155.
Testo completoAbstract (sommario):
Surface water concentrations of dissolved nutrients and phytoplankton biomass (as chlorophyll a) were examined monthly in relation to physicochemical characteristics and rainfall for 30 months in two tropical, tidally dominated mangrove creeks in north Queensland, Australia. Dissolved nutrient concentrations and phytoplankton biomass peaked during summer with no or little significant change throughout the rest of the year. Dissolved nitrogen and phosphorus concentrations correlated inversely with salinity changes, implying that fresh water and suspended material from the watershed were the main source of dissolved nutrients.The mean dissolved inorganic N : P ratio in each creek (Control Creek 58 : 1, Sandfly Creek 26 : 1) was greater than the Redfield ratio (16 : 1), suggesting excess nitrogen relative to phosphorus. Variability in phytoplankton biomass did not correlate significantly with dissolved nitrogen or phosphorus concentrations, but did relate to rainfall patterns and changes in dissolved oxygen concentrations.These results suggest that pelagic conditions in these mangrove creeks are constant all year round, except during the summer wet season.
21
Walker, Andrea C., e Tim Thompson. "Muscogee Creek Spirituality and Meaning of Death". OMEGA - Journal of Death and Dying 59, n. 2 (ottobre 2009): 129–46. http://dx.doi.org/10.2190/om.59.2.c.
Testo completoAbstract (sommario):
This qualitative, collective case study involves interviews with 27 members of the Muscogee Creek Tribe to explore spirituality as related to death and bereavement. Results yielded that Creeks are generally open to the existence of inexplicable supernatural events. Creek spirituality encompasses awareness of spiritual beings, both good and bad. Participants believed that spirits exist alongside people and can send and receive messages from people to guide and inform them. Creeks have ongoing, though not constant, relationships with loved ones and others who have died. Spiritual attunement can occur at every point in the life cycle but seems to be especially astute in children and animals. Results are discussed in terms of continuing bonds and meaning making perspectives.
22
Miltner, Robert J., Steve W. Ross e Martin H. Posey. "Influence of food and predation on the depth distribution of juvenile spot (Leiostomus xanthurus) in tidal nurseries". Canadian Journal of Fisheries and Aquatic Sciences 52, n. 5 (1 maggio 1995): 971–82. http://dx.doi.org/10.1139/f95-096.
Testo completoAbstract (sommario):
Relative abundances of young-of-the-year (YOY) spot (Leiostomus xanthurus) sampled by trawling in two tidal creeks on Masonboro Island, North Carolina, were highest in the shallow creek margins. Abundances of benthic invertebrates sampled by cores in one of the study creeks, were also maximal at the creek margin. Polychaetes associated with the creek margin composed the largest fraction of spot diets, indicating spot located in the creek margins were in the area of highest food availability. Spot predators sampled by trawling and seining were uncommon and were primarily juvenile (75–200 mm total length) southern flounder (Paralichthys lethostigma), hake (Urophycis spp.), and bluefish (Pomotomus saltatrix). Large YOY spot experienced a size refuge from predation, as only small YOY spot were found in predator stomachs. In laboratory experiments testing the effects of the presence of a predator, food, or both food and predators on the depth distribution of YOY spot, food had a stronger effect on spot distributions than predators The results of field observations and laboratory experiments suggest food has the strongest effect on spot distribution in the field, and that food is relatively more important than refuge from predation to the nursery function of shallow estuarine habitats.
23
Chakma, Prabin, Shaikh Shamim Hasan, S. M. Rafiquzzaman e Md Jahangir Alam. "Farmers’ Attitude Towards Ponds and Creeks Use in Some Selected Hilly Areas of Bangladesh". European Journal of Agriculture and Food Sciences 3, n. 5 (2 settembre 2021): 16–22. http://dx.doi.org/10.24018/ejfood.2021.3.5.349.
Testo completoAbstract (sommario):
This study explores the status and potential of creek and pond as well as the attitude of the farmers towards pond and creek use. Following random sampling technique, a total of 60 fish farmers were sampled from Panchari Upazila, Khagrachari district of Bangladesh who were involved with pond and/or creek culture and they were interviewed through a predesigned questionnaire. The findings of the study indicated that most of the respondents belonged to above 50 years of age while 95% of them had small to medium (2-7 members) family size and about 72% of whom were literate either from primary to more than SSC level. Out of all the farmers, 85% of them had their own pond/creek and only 25% of them maintained communication with the fisheries related personnel (SUFO/UFO/others) to receive fish extension related information although, 36.7% of them didn’t receive any training on agriculture and aquaculture related issues. By producing different types of fishes, they earned an average BDT 35915.25 from aquaculture which helped them maintaining positive attitude towards ponds and creeks use. The respondents of the study area perceived that ponds/creeks fish culture helped to increase their family income in the hilly areas and also uplifted their self-employment. Out of all the farmers, 65% had moderately to highly favorable attitude towards ponds and creeks use. Linear regression analysis indicated that age, level of education, income from aquaculture, agricultural training received, and aquaculture training received of the farmers had significant contribution on their attitude. The respondents of the study area perceived that ponds/creeks fish culture helped to increase family income in the hilly areas and also uplifted their self-employment.
24
Pulatsü, Serap, e Dijar Latifi. "Evaluation of health risks from heavy metals in the creeks feeding Mogan Lake, Türkiye". Ege Journal of Fisheries and Aquatic Sciences 40, n. 3 (15 settembre 2023): 219–27. http://dx.doi.org/10.12714/egejfas.40.3.09.
Testo completoAbstract (sommario):
The non-carcinogenic and carcinogenic health risks arising from potential exposure to heavy metals pose a negative threat to human health. In this study, heavy metals (Hg, As, Cd, Cr, Pb, Ni, Cu, Zn) analyses were conducted in the waters of four creeks in the Mogan Lake Basin (Sukesen Creek, Başpınar Creek, Yavrucak Creek, Gölcük Creek) under anthropogenic pressure. In the water samples taken from the creeks that also contribute to Mogan Lake, which has significant recreational importance in the basin: a) The non-carcinogenic health risks (HQ) of exposure to heavy metals through ingestion and dermal routes were identified for adults and children, b) The total potential non-carcinogenic health risks for adults and children were determined using the hazard index (HI). The total HI (THI) value was calculated as the sum of individual HIs (HIingestion + HIdermal), c) Carcinogenic health risk (CR) values were calculated for three heavy metals (Cr, Ni and As). According to the findings: a) Ingestion HQ values were found to be higher in adults and children due to As compared to dermal HQ values. According to the HI values, there was a high level of non-carcinogenic health risk in terms of heavy metals in Sukesen, Başpınar, and Gölcük Creeks, varying according to the month and age group. However, for Yavrucak Creek, there has not been appeared to be a non-carcinogenic health risk for adults and children, b) According to the calculated HQdermal and HIdermal values, there was no significant adverse health risk due to dermal exposure for adults and children, c) Children hazard index values were found to be higher than adult hazard index values, highlighting that children were at higher health risk most particularly when it comes to the considered heavy metals, d) The THI values for Sukesen and Başpınar Creeks indicated a significant non-carcinogenic health risk possibility for both adults and children in all sampled months. In Gölcük Creek, a serious non-carcinogenic health risk probability was observed for adults in April and for children during the sampling period, e) The calculated CR values for chromium, nickel, and arsenic indicated that the ingestion pathway poses a higher risk compared to the dermal route, expressing the likelihood of cancer incidence in adults and children. In the context of potential health hazards, to take administrative measures regarding heavy metal contamination, particularly in Başpınar and Sukesen Creeks, is important not only for the protection of public health but also for the sustainability of Mogan Lake.
25
Beckingham, Barbara A., Michael Shahin, Kathryn Ellis e Timothy J. Callahan. "Polycyclic Aromatic Hydrocarbons and Suspended Materials in a Semi-urbanized Tidal Creek after an Historic Flood Event and Implications for Water Quality Monitoring". Journal of South Carolina Water Resources, n. 4 (1 giugno 2017): 3–11. http://dx.doi.org/10.34068/jscwr.04.01.
Testo completoAbstract (sommario):
Tidal creeks transport both dissolved and particulate natural organic carbon materials and contaminants, connecting land-based activities with estuarine surface waters. It is important to characterize these materials in tidal creeks because it provides insights as to their origins and potential for ecosystem impacts. Surface water samples were collected from Bull Creek, Charleston, SC, a semi-urbanized tidal creek wetland, on five sampling dates from fall 2015 to spring 2016 to measure total suspended solids (TSS), turbidity, dissolved organic carbon (DOC), SUVA254 (specific absorbance as an indicator of aromaticity of DOC), and total water concentrations of polycyclic aromatic hydrocarbons (PAHs), a ubiquitous class of hydrophobic organic contaminants of concern. Stream discharge was also measured to allow an estimation of material flux. One of the sampling dates captured these parameters following a historic rainfall related to Hurricane Joaquin in October 2015, and therefore the aim of the present study is to characterize the sources and to quantify the transport of carbonaceous materials and PAHs in Bull Creek, with a focus on the response to this storm event. The quality of suspended solids and DOC were different following the October storm event in comparison to the other sampling dates, and they were more terrestrially derived as shown by shifts in SUVA254 and correlations between TSS and turbidity. Elevated levels of PAHs were detected in Bull Creek after the storm, and diagnostic ratios indicated that additional mixed sources were mobilized by the event. Combining the measures of both carbonaceous material quality and PAH profile contributed to a better understanding of the sources to the tidal creek. Shifts in PAH sources and suspended materials have implications for PAH toxicity to aquatic life, as well as for the appropriate approach to water quality monitoring. Future work should aim to develop relationships between discharge, suspended materials, and PAHs to facilitate more continuous monitoring of material transport in tidal creeks, especially during storm events, which have a strong influence on water quality.
26
Hendry, A. P., e T. P. Quinn. "Variation in adult life history and morphology among Lake Washington sockeye salmon (Oncorhynchus nerka) populations in relation to habitat features and ancestral affinities". Canadian Journal of Fisheries and Aquatic Sciences 54, n. 1 (1 gennaio 1997): 75–84. http://dx.doi.org/10.1139/f96-257.
Testo completoAbstract (sommario):
Body size, age composition, and male body depth were compared among five Lake Washington sockeye salmon (Oncorhynchus nerka) populations. Two of the populations (Bear and Cottage creeks) were indigenous to the watershed and three (Cedar River, Issaquah Creek, and Pleasure Point) were non-native (from Baker Lake, Washington). To isolate the relative contributions of habitat type and ancestral relatedness to phenotypic variation, we compared populations with (i) the same origin and similar habitats, (ii) different origins and different habitats, (iii) the same origin and different habitats, and (iv) different origins and similar habitats. Spawning salmon in the Cedar River were older and larger than those in the native populations, a result consistent with their origin (contemporary Baker Lake fish were also large and old) and with habitat variation (the Cedar River is much larger than Bear and Cottage creeks). Body size and age composition did not differ among the three non-native populations, but the body depth of males spawning on the lake beach (Pleasure Point) was greater than that of males in the Cedar River, suggesting adaptive divergence. Adaptive convergence may also have occurred because the population in Issaquah Creek (intermediate-sized creek) did not differ appreciably from those in Bear and Cottage creeks.
27
Hahn, S. C. "African Creeks: Estelvste and the Creek Nation". Ethnohistory 55, n. 4 (1 ottobre 2008): 690–91. http://dx.doi.org/10.1215/00141801-2008-028.
Testo completo
28
Krauthamer, Barbara. "African Creeks: Estelvste and the Creek Nation". Western Historical Quarterly 40, n. 1 (febbraio 2009): 80.1–80. http://dx.doi.org/10.1093/whq/40.1.80.
Testo completo
29
Confer, Clarissa W. "African Creeks: Estelvste and the Creek Nation". Journal of American Ethnic History 28, n. 1 (1 ottobre 2008): 120–21. http://dx.doi.org/10.2307/27501890.
Testo completo
30
Lu, Z. Y., e D. M. Cruden. "Two debris flow modes on Mount Cayley, British Columbia". Canadian Geotechnical Journal 33, n. 1 (25 marzo 1996): 123–39. http://dx.doi.org/10.1139/t96-028.
Testo completoAbstract (sommario):
The 1963 landslide on Mount Cayley, British Columbia, began at the head of Dusty Creek, a small tributary of Turbid Creek, a major creek draining Mount Cayley, and terminated at the present confluence of Dusty and Turbid creeks. About 5 × 106 m3 of partially saturated, columnar-jointed dacite and weak pyroclastic rocks moved 2.4 km downstream. The depletion zone contained three separate blocks. The landslide deposits have distinct layers that can be traced back to similar bedrock units in the undisturbed material, which are three times thicker. The accumulation zone is divided by two gullys into three blocks, which preserve, much thinned, different but overlapping portions of the volcanic stratigraphy. The 1984 rock slide on Avalache Creek, 0.8 km away, involved tuff breccia, tuff lapilli, and tuff, all easily broken. Its main track ran over thick snow and ice on the bottom of the creek. Differences in water content and displaced material led to different flow modes: the 1963 fragments formed laminar flows, which supported comparatively undeformed central plugs; the turbulent 1984 flow's deposits have no distinct layers. The two modes, laminar flow and turbulent flow, also formed different types of landslide dams. Key words: landslide, debris flow, volcano, British Columbia, tuff, lava.
31
Rudershausen, PJ, e JA Buckel. "Urbanization impacts on production and recruitment of Fundulus heteroclitus in salt marsh creeks". Marine Ecology Progress Series 645 (9 luglio 2020): 187–204. http://dx.doi.org/10.3354/meps13378.
Testo completoAbstract (sommario):
It is unclear how urbanization affects secondary biological production in estuaries in the southeastern USA. We estimated production of larval/juvenile Fundulus heteroclitus in salt marsh areas of North Carolina tidal creeks and tested for factors influencing production. F. heteroclitus were collected with a throw trap in salt marshes of 5 creeks subjected to a range of urbanization intensities. Multiple factor analysis (MFA) was used to reduce dimensionality of habitat and urbanization effects in the creeks and their watersheds. Production was then related to the first 2 dimensions of the MFA, month, and year. Lastly, we determined the relationship between creek-wide larval/juvenile production and abundance from spring and abundance of adults from autumn of the same year. Production in marsh (g m-2 d-1) varied between years and was negatively related to the MFA dimension that indexed salt marsh; higher rates of production were related to creeks with higher percentages of marsh. An asymptotic relationship was found between abundance of adults and creek-wide production of larvae/juveniles and an even stronger density-dependent relationship was found between abundance of adults and creek-wide larval/juvenile abundance. Results demonstrate (1) the ability of F. heteroclitus to maintain production within salt marsh in creeks with a lesser percentage of marsh as long as this habitat is not removed altogether and (2) a density-dependent link between age-0 production/abundance and subsequent adult recruitment. Given the relationship between production and marsh area, natural resource agencies should consider impacts of development on production when permitting construction in the southeastern USA.
32
Gu, Yan, Huan Li e Ming Jie Gong. "Analysis of the Evolution of Xiaomiaohong Based on Remote Sensing Axis Line Method". Applied Mechanics and Materials 405-408 (settembre 2013): 3061–64. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.3061.
Testo completoAbstract (sommario):
With the rapid development of tidal flat reclamation and construction of port in the Marine East of Jiangsu project, Xiaomiaohong creek nearby Lvsi port located at radial sand ridges sea area was selected as a typical area for understanding its topographic and morphological evolution, which is conductive to the construction of port. By using the Remote Sensing Axis Line method (RSAL), the Axis lines of Xiaomiaohong creek were extracted based on one MSS image and six TM images in the period of 1979, 1987, 1989, 1993, 1995, 2003 and 2009. The results showed that: (1) on the basis of overlaying generated axis line and DEM (digital elevation model) data both acquired in 2003, axis line can be the substitution of the thalweg line because of similar trend and minor deviation of above two kinds of lines, which is revealed that RSAL was serviceable and effective to understand dynamic evolution of tidal creeks quickly and accurately; (2) deviation between axis line and thalweg line is inevitable because of the slopes of both side is asymmetric. The biased distance depended on the slope degree of creeks. The much larger slope degree is, the further distance is shifted; (3) from 1979 to 2009, the front end of Xiaomiaohong creek were growing and its subordinate branches were eroding. Some new subordinate branches were turned out and developed in southern part caused by the strong hydrodynamic condition. Based on the comparison, the entire tidal creek was relatively stable.
33
Huang, Wen Dan, Xiang Min Zheng e Li Min Zhou. "Preliminary Study on Dissolved and Colloidal Organic Carbon in Tidal Creek of Chongming Dongtan". Advanced Materials Research 317-319 (agosto 2011): 2436–39. http://dx.doi.org/10.4028/www.scientific.net/amr.317-319.2436.
Testo completoAbstract (sommario):
Water samples were collected in the northern, eastern and southern tidal creeks of Chongming Dongtan in January, 2009. The samples were passed through 0.45μm pore size GF/C glass fiber membrane and colloid was isolated by mini tangential flow ultrafiltration (TFF) with ultrafiltration membrane pore-size of 1kD (1kD=1 000 Daltons). Then the content of organic carbon was tested by TOC II. Results show that the contents of dissolved and colloidal organic carbon (DOC and COC) in the northern creek are higher than the eastern and southern tidal creeks of Chongming Dongtan, and the concentration of DOC decreased from high tidal flat to low tidal flat. Hydrodynamic and vegetation are the important factors to affect the content of COC in tidal creek water of Chongming Dongtan.
34
Fedortchouk, Yana, e William LeBarge. "Sources of placer platinum in Yukon: provenance study from detrital minerals". Canadian Journal of Earth Sciences 45, n. 8 (agosto 2008): 879–96. http://dx.doi.org/10.1139/e08-032.
Testo completoAbstract (sommario):
Source rocks for the platinum group minerals (PGM), historically reported in a number of Yukon placers, remain either unknown or poorly understood. A study of heavy-mineral samples from five creeks draining bedrock in west and central Yukon was undertaken to confirm the presence of placer platinum, to determine which mafic–ultramafic rock is the source of PGM in Kluane area, southern Yukon, and to explain platinum occurrences in Canadian and Florence creeks, central Yukon, where no known mafic–ultramafic rocks are present. Diverse composition of chromian spinel and clinopyroxenes from three creeks in the Kluane area indicate several sources of ultramafic rocks, including fragments of Alpine-type peridotites formed in back-arc basin and mid-ocean-ridge settings, and a source rock for zoned zinc-rich chromites of unknown origin. The Kluane ultramafic sills are the most likely source of PGM in this area. The heavy-mineral sample from Canadian Creek returned one PGM grain, no chromite, and abundant ilmenite and titanomagnetite. A group of chromium-rich magnesian ilmenites (∼4 wt.% MgO) closely match the composition of ilmenites from continental mafic intrusions produced during continental rift magmatism. This supports the continental rifting event recently proposed for this part of Yukon and indicates the economic potential of the Canadian Creek platinum occurrence. Composition of spinel from Florence Creek sample indicates an Alaskan-type intrusion as the source of PGM.
35
Nábělková, J., G. Šťastná e D. Komínková. "Flood impact on water quality of small urban streams". Water Science and Technology 52, n. 12 (1 dicembre 2005): 267–74. http://dx.doi.org/10.2166/wst.2005.0481.
Testo completoAbstract (sommario):
Flood situation (August 2002) in small urban streams radically changed status of water ecosystem, which had been created naturally and anthropogenically for a long time. The aim of the after-flood research has been to record development of a creek recovery in positive as well as negative sense: recovery of benthic colonisation and reloading of contaminants (heavy metals) in bottom sediment. The Botic creek (its one section) was chosen as an experimental stream. This section of the creak is influenced by combine sewer system (two overflows – CSOs) as well as storm sewer system (one outlet – SSO). Heavy metals concentrations in water, sediment and body tissue of benthic organisms of the Botic creek and quality of benthic communities were monitored long term before flood. Comparison of results before and after flood can better assess impact of extreme water stage on a small stream.
36
KC, Diwakar, e Liangbo Hu. "Post-Wildfire Debris Flows in Montecito, California (USA): A Case Study and Empirically Based Debris Volume Estimation". Geotechnics 3, n. 2 (15 maggio 2023): 347–59. http://dx.doi.org/10.3390/geotechnics3020020.
Testo completoAbstract (sommario):
Wildfires have a strong influence on various geotechnical and hydraulic properties of soils and sediments, which may become more vulnerable to landslides or debris flows. In the present study, a case investigation of the 2018 post-wildfire debris flows in Montecito, California, USA, was conducted, with a focus on the wildfire-affected areas and debris volume estimation. Significant debris were deposited around four major creeks, i.e., Montecito Creek, San Ysidro Creek, Buena Vista Creek, and Romero Creek in January, 2018, one month after the Thomas fire. Satellite images utilizing remote sensing techniques and geographic information system (GIS) data were analyzed to identify areas affected by the wildfire. Relevant data, including the slope, catchment area, and rainfall were used in two empirical models to estimate the debris volumes around the four creeks. As compared with field observation, each debris volume estimated with these empirical models was within the same order of magnitude. The debris volumes were generally underestimated when using the rainfall recorded at the Montecito Weather Station; the estimates considerably improved with the rainfall record from the Doulton Tunnel Station. The results showed that, overall, such empirical approaches are still of benefit for engineering practice, as they are capable of offering first-order approximations. The accuracy and availability of rainfall data are critical factors; the rainfall data in mountainous areas are generally higher than in the low lands, and consequently were more suitable for debris volume estimation in the present study, where the debris flows typically occurred in areas with steep slopes and at higher elevations.
37
RODRIGUES, Carlos A. L., Rannyele P. RIBEIRO, Nayara B. SANTOS e Zafira S. ALMEIDA. "Patterns of mollusc distribution in mangroves from the São Marcos Bay, coast of Maranhão State, Brazil". Acta Amazonica 46, n. 4 (dicembre 2016): 391–400. http://dx.doi.org/10.1590/1809-4392201600493.
Testo completoAbstract (sommario):
ABSTRACT The diversity and distribution of molluscs from the Amazon Coast of Maranhão State, Brazil, are poorly understood. The aim of this study was to investigate how molluscs in two mangrove creeks (Buenos Aires and Tronco) at the São Marcos Bay, coast of the Maranhão State, respond to spatial and temporal variations in the environment. Sampling was performed in the intertidal area along three zones established using a straight line transect of 100 m. Abiotic variables of water and sediment were measured at each creek. We found 5,912 specimens belonging to 23 species and 15 families of epifaunal and infaunal molluscs. The patterns of their distribution in the two creeks were different. Salinity, dissolved oxygen, and rainfall were the main variables that affected the temporal distribution of molluscs. We found low species richness in the overall mollusc composition. Diversity in the Buenos Aires Creek was lower than that observed in the Tronco Creek, possibly because of activities of a port located in proximity to the former. The spatial distribution of molluscs along the zones followed an abundance and diversity gradient, mainly influenced by exposure time during low tide. Port activities may influence the patterns of mollusc distribution in the surrounding mangroves, and we thus highlight the importance of management and monitoring of these areas.
38
VanDine, D. F. "Debris flows and debris torrents in the Southern Canadian Cordillera". Canadian Geotechnical Journal 22, n. 1 (1 febbraio 1985): 44–68. http://dx.doi.org/10.1139/t85-006.
Testo completoAbstract (sommario):
In Canada, debris torrents (also referred to as channelized debris flows) occur in parts of British Columbia, Alberta, and the Yukon. At least 17 deaths and an estimated $100 million of damage to bridges and property can be attributed to this natural hazard. The debris mainly comprises large boulders, rock fragments, gravel- to clay-sized material, tree and wood mulch—materials that accumulate in the mountain creeks. To be susceptible to a debris torrent, a creek must have a drainage area within a critical range, a profile that is sufficiently steep, an accumulation of debris, and some form of triggering mechanism. The most common triggering mechanism is an extreme water discharge, which may result from a very intense rainfall or a temporary damming of the creek. In western Canada, the resulting torrents involve masses of debris, typically less than 50 000 m3, that travel down creeks at speeds between 3 and 12 m/s.Several passive and active forms of mitigation can be used to reduce the impact of debris torrents on creek crossings and neighbouring residents. Passive mitigation methods include avoidance of the area, relocation of structures and facilities, land use restrictions, and some form of warning system. Active mitigation methods include remedial measures to remove or counter the causes, and various forms of designed protection. Constructing check dams near the headwaters of the creek and stabilizing the valley slopes that border the creeks are examples of remedial measures. Constructing debris barriers or clear span bridges with adequate clearance are examples of designed protection.Howe Sound, north of Vancouver, British Columbia, has had a relatively high number of debris torrents. Recently, several major studies have addressed the extent of the hazard and recommended mitigative measures for this area. Many of the examples presented in this paper are drawn from this case history. Key words: debris flows, debris torrents, slope stability, Southern Canadian Cordillera, Howe Sound, geological process, design considerations.
39
Driver, Lucas J., e David J. Hoeinghaus. "Spatiotemporal dynamics of intermittent stream fish metacommunities in response to prolonged drought and reconnectivity". Marine and Freshwater Research 67, n. 11 (2016): 1667. http://dx.doi.org/10.1071/mf15072.
Testo completoAbstract (sommario):
Hydrological regimes are primary drivers of community structure and dynamics in streams with strong seasonal or annual flood and drought cycles. In the current study, we investigated the dynamics of fish metacommunities in two intermittent streams (Hickory Creek and Clear Creek) in north Texas, USA, by examining changes in diversity, abundance, assemblage structure and temporal stability associated with prolonged seasonal drought and reconnectivity. Diversity (α and γ), abundance and stability increased with initial isolation during summer drought but dramatically declined as drought or drying persisted through the winter (November–December). During post-drought reconnectivity in Hickory Creek, diversity and abundance increased and approached pre-drought levels. Abundance and body size varied greatly among species and indicated species-specific responses (i.e. mortality, recruitment, dispersal) to hydrologic fragmentation and connectivity. Ultimately, assemblage structures were significantly altered by drought in Hickory and Clear creeks, and despite a trend towards recovery in Hickory Creek, assemblages did not fully recover during the present study. Intermittent-stream fishes may be generally adapted to natural drought dynamics; however, climate change and human-mediated habitat alterations may result in prolonged and intensified drought conditions that exceed many species mechanisms of resistance or resilience having potentially large impacts on biodiversity across spatial and temporal scales.
40
Baig, Mirza Salman, Zaheer Uddin e Ambreen Insaf. "The Parametric Estimation of Tidal Potential Power Density using Modeling Strategies at Hajambro Creek of Indus Delta, Pakistan". Proceedings of the Pakistan Academy of Sciences: A. Physical and Computational Sciences 58, n. 2 (24 dicembre 2021): 19–27. http://dx.doi.org/10.53560/ppasa(58-2)600.
Testo completoAbstract (sommario):
There are many accessible resources for electricity generation using renewable energy, like, solar, wind, tidal and wave etc. The output of all these resources depend on weather conditions, force of gravity or rotation of the Earth, but tidal energy has a major advantage over many other forms of renewable generation as it is predictable over a long period of time. Pakistan has about 1000 km long coastline with complex network of creeks in the Indus delta region which include 17 major creeks and further divide into a number of estuaries with considerable tidal ranges and tidal current. This research study is carried out at one of these major creeks namely Hajambro (Hajambro river) and extends from Hajambro 24ᵒ 08’N 67ᵒ 22’E (sea mouth) to Keti Bander 24ᵒ 09’N 67ᵒ 27’E (mouth of river Indus). Study area is targeted within creek region where there is a large shortfall of electricity observed and this situation has threaten the community socioeconomically. In this research study, available tidal energy resources of Hajambro creek are assessed, tidal power density models and bathymetry model are developed in Arc-GIS (geographical informationsystem) environment, for the first time. A comprehensive tidal turbine technology review is conducted and based on up-to-date tidal turbine technology review and results achieved from assessment of tidal energy resources, deployment of a turbine at Hajambro creek is proposed. With effective area of 9.46 km2 mean spring estimated power (seasonally) is observed as 14 MW in winter, 12.9 MW in Pre-Monsoon, 13.6 MW in Monsoon and 13.1 MW in Post-Monsoon.
41
Landmeyer, James E., W. Scott McBride e William B. Tate. "Determination of Recharge Areas That Supply Decades Old Groundwater to Creeks Inhabited by the Threatened Okaloosa Darter". Hydrology 9, n. 5 (25 aprile 2022): 69. http://dx.doi.org/10.3390/hydrology9050069.
Testo completoAbstract (sommario):
The Okaloosa darter (Etheostoma okaloosae) is a diminutive, perch-like, benthic fish that inhabits only six small, clear, and shallow creek systems that flow almost entirely within Eglin Air Force Base in the panhandle of northwest Florida. Listed as Endangered by the U.S. Fish and Wildlife Service (USFWS) in 1973, improvements in erosion control and habitat restoration led to the Okaloosa darter being downlisted from Endangered to Threatened in 2011. However, the long-term management of the species is hampered by the lack of knowledge of the spatial extent of the recharge areas that ultimately support creek flow through groundwater discharge. To address this lack of data, we collected groundwater samples from the sand and gravel aquifer beneath 11 headwater and 11 downgradient sites across six creek basins during February and December 2020. The groundwater samples were collected from 1 to 1.2 m beneath the creek bottom. Concentrations of sulfur hexafluoride (SF6) were analyzed and used to calculate groundwater age (residence time), and indicated that at the 11 headwater sites, recharge occurred between 11 and 28 years ago. Groundwater ages in downgradient parts of the same creeks indicated that recharge occurred between 5 and 25 years ago. When combined with representative values of hydraulic conductivity for the sand and gravel aquifer, the ages reveal that the extent of the maximum recharge distance from the sampling sites ranged from about 222 to 2011 m from the creeks. This new information can be used by natural resource managers as additional evidence to support the USFWS Recovery Plan and proposed delisting of the Okaloosa darter from the Endangered Species List. Moreover, these results may also be useful to fisheries biologists to incorporate groundwater inputs to facilitate fisheries management.
42
Landmeyer, James E., W. Scott McBride e William B. Tate. "Determination of Recharge Areas That Supply Decades Old Groundwater to Creeks Inhabited by the Threatened Okaloosa Darter". Hydrology 9, n. 5 (25 aprile 2022): 69. http://dx.doi.org/10.3390/hydrology9050069.
Testo completoAbstract (sommario):
The Okaloosa darter (Etheostoma okaloosae) is a diminutive, perch-like, benthic fish that inhabits only six small, clear, and shallow creek systems that flow almost entirely within Eglin Air Force Base in the panhandle of northwest Florida. Listed as Endangered by the U.S. Fish and Wildlife Service (USFWS) in 1973, improvements in erosion control and habitat restoration led to the Okaloosa darter being downlisted from Endangered to Threatened in 2011. However, the long-term management of the species is hampered by the lack of knowledge of the spatial extent of the recharge areas that ultimately support creek flow through groundwater discharge. To address this lack of data, we collected groundwater samples from the sand and gravel aquifer beneath 11 headwater and 11 downgradient sites across six creek basins during February and December 2020. The groundwater samples were collected from 1 to 1.2 m beneath the creek bottom. Concentrations of sulfur hexafluoride (SF6) were analyzed and used to calculate groundwater age (residence time), and indicated that at the 11 headwater sites, recharge occurred between 11 and 28 years ago. Groundwater ages in downgradient parts of the same creeks indicated that recharge occurred between 5 and 25 years ago. When combined with representative values of hydraulic conductivity for the sand and gravel aquifer, the ages reveal that the extent of the maximum recharge distance from the sampling sites ranged from about 222 to 2011 m from the creeks. This new information can be used by natural resource managers as additional evidence to support the USFWS Recovery Plan and proposed delisting of the Okaloosa darter from the Endangered Species List. Moreover, these results may also be useful to fisheries biologists to incorporate groundwater inputs to facilitate fisheries management.
43
Kuijper, Marijn, e Perry de Louw. "Brackish water ecosystem restoration based on integrated water system design". Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation 38, n. 1 (1 gennaio 2007): 115–25. http://dx.doi.org/10.2478/v10060-008-0028-z.
Testo completoAbstract (sommario):
Brackish water ecosystem restoration based on integrated water system design Despite their current location within a primary agricultural area, most of the creek remnants in the Dutch clay polder areas have a high potential for recovery into healthy ecosystems. Like most areas in the Netherlands the clay polders are densely populated. Therefore multifunctional land use is encouraged and different types of land use coexist within small distances from each other. As a result water conflicts occur: agricultural land use requires deep groundwater levels and causes eutrophication by spreading nutrients into the water system, while existing ecosystems within and around the creek remnants need wetland conditions and low nutrient levels. Furthermore periods of high discharge cause flooding of arable land. Extreme measures like filling in ditches and increasing water levels are needed to achieve the water targets for wetlands around the creeks. On the other hand, the effects of these measures easily cause water logging in nearby agricultural areas. We introduce an integrated approach for the restoration of creek ecosystems. Both the complex interaction of groundwater, surface water and ecology and the limiting conditions imposed by adjacent agricultural land use, spatial developments and regulatory settings like the European Water Framework Directive are thereby taken into account. A highly integrated set of measures is proposed creating optimal conditions for both high agricultural production and flourishing creek ecosystems.
44
Steineker, Rowan Faye. "“Fully Equal to That of Any Children”: Experimental Creek Education in the Antebellum Era". History of Education Quarterly 56, n. 2 (maggio 2016): 273–300. http://dx.doi.org/10.1111/hoeq.12183.
Testo completoAbstract (sommario):
During the 1840s and 1850s, members of the Creek Nation rejected schools as a colonial tool and instead experimented with various forms of education to fit their own local and national needs. Diverse individuals and communities articulated educational visions for their nation in conversation with fellow citizens, national leaders, and U.S. educators. Rather than embrace education to assimilate into the American republic, Creeks turned to schools and English literacy as one strategy to shape their own society and defend it from further Euro-American colonial policies. By the end of the 1850s, they had established a fledgling national school system consisting of both neighborhood and mission schools. These institutions reflected and reinforced changes in race, class, gender, culture, and religion in the antebellum Creek Nation.
45
Thompson, T. E., W. D. Goff, M. L. Nesbitt, R. E. Worley, R. D. O'Barr e B. W. Wood. "`Creek' Pecan". HortScience 32, n. 1 (febbraio 1997): 141–43. http://dx.doi.org/10.21273/hortsci.32.1.141.
Testo completo
46
Tanner, Anita. "Creek Skating". Dialogue: A Journal of Mormon Thought 52, n. 3 (1 ottobre 2019): 111. http://dx.doi.org/10.5406/dialjmormthou.52.3.0111.
Testo completo
47
Healy, Donald T. "Thlopthlocco Creek". Raven: A Journal of Vexillology 3 (1996): 175–76. http://dx.doi.org/10.5840/raven1996/19973/4106.
Testo completo
48
Healy, Donald T. "Kialegee Creek". Raven: A Journal of Vexillology 3 (1996): 71. http://dx.doi.org/10.5840/raven1996/19973/444.
Testo completo
49
Messer, Richard E. "Mud Creek". Psychological Perspectives 52, n. 2 (27 maggio 2009): 256. http://dx.doi.org/10.1080/00332920902881075.
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50
Hanlen, Jim. "Goodbye Creek". English Journal 81, n. 7 (novembre 1992): 98. http://dx.doi.org/10.2307/820763.
Testo completo