scholarly journals Assessing Water and Nutrient Long-Term Dynamics and Loads in the Enxoé Temporary River Basin (Southeast Portugal)

Water ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 354 ◽  
Author(s):  
David Brito ◽  
Ramiro Neves ◽  
Maria Branco ◽  
Ângela Prazeres ◽  
Sara Rodrigues ◽  
...  
Keyword(s):  
Algal Blooms ◽  
Field Data ◽  
Trophic State ◽  
Assessment Tool ◽  
Geometric Mean ◽  
Light Availability ◽  
Nutrient Loads ◽  
Management Scenarios ◽  
High Concentrations

The Enxoé reservoir has been exhibiting frequent high chlorophyll-a concentrations (reaching a geometric mean six times the national limit for eutrophication of 10 μg L−1) since 2000, and represents the reservoir with the highest eutrophic state in Portugal. Toxic algal blooms have also been observed, which pose serious challenges to water managers, as the reservoir is used for potable water production. In an effort to contribute to the reduction of the reservoir trophic state, the watershed inputs (monthly flows, sediment, nitrogen (N) and phosphorus (P) loads) were characterized with the Soil Water Assessment Tool (SWAT). Field data were collected in the ungauged watershed during 2010 and 2011. Model results were then used to characterize the long-term watershed dynamics in terms of water and nutrients. SWAT estimates of the simulated flow, and the sediment and nutrient loads were in good agreement with field data (R2 between 0.42–0.78; Nash-Sutcliffe efficiencies between 0.19–0.75). The Enxoé River was characterized by a temporary flushy regime where high concentrations were transported in short time periods. As a result, nutrient loads delivered to the Enxoé reservoir were estimated to be 18 tonN year−1 and 0.7 tonP year−1 (30 years’ simulation), reaching the reservoir mainly by runoff. These results were consistent with the gentle slopes, extensive agricultural activities, and low urban pressure observed in Enxoé. The magnitude of the nutrient exports suggests that the reservoir eutrophication may also be linked to the reservoir geometry (average depth of 5 m), which provides high light availability to the bottom sediments. Thus, SWAT results were integrated into a reservoir model to depict the origin of the Enxoé trophic state and test management scenarios that may reduce it.

scholarly journals Modelling groundwater quality of the Athabasca River Basin in the subarctic region using a modified SWAT model

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tesfa Worku Meshesha ◽  
Junye Wang ◽  
Nigus Demelash Melaku ◽  
Cynthia N. McClain
Keyword(s):  
Groundwater Quality ◽  
Assessment Tool ◽  
Swat Model ◽  
Surface Water Quality ◽  
Global Scale ◽  
Coefficient Of Determination ◽  
Nutrient Loads ◽  
Management Scenarios ◽  
Subarctic Region ◽  
Human Welfare

AbstractGroundwater is a vital resource for human welfare. However, due to various factors, groundwater pollution is one of the main environmental concerns. Yet, it is challenging to simulate groundwater quality dynamics due to the insufficient representation of nutrient percolation processes in the soil and Water Assessment Tool model. The objectives of this study were extending the SWAT module to predict groundwater quality. The results proved a linear relationship between observed and calculated groundwater quality with coefficient of determination (R2), Nash–Sutcliffe efficiency (NSE), percent bias (PBIAS) values in the satisfied ranges. While the values of R2, NSE and PBIAS were 0.69, 0.65, and 2.68 during nitrate calibration, they were 0.85, 0.85 and 5.44, respectively during nitrate validation. Whereas the values of R2, NSE and PBIAS were 0.59, 0.37, and − 2.21 during total dissolved solid (TDS) calibration and they were 0.81, 0.80, 7.5 during the validation. The results showed that the nitrate and TDS concentrations in groundwater might change with varying surface water quality. This indicated the requirement for designing adaptive management scenarios. Hence, the extended SWAT model could be a powerful tool for future regional to global scale modelling of nutrient loads and effective surface and groundwater management.

Water quality and phytoplankton dynamics in Moreton Bay, south-eastern Queensland. II. Mathematical modelling.

1998 ◽  
Vol 49 (3) ◽  
pp. 227 ◽  
Author(s):  
James McEwan ◽  
Albert J. Gabric ◽  
Peter R. F. Bell
Keyword(s):  
Water Quality ◽  
Field Data ◽  
Nutrient Loading ◽  
Light Availability ◽  
Population Pressure ◽  
Eastern Region ◽  
Nutrient Loads ◽  
Quality Model ◽  
Moreton Bay ◽  
European Settlement

A coupled hydrodynamic water-quality model of Moreton Bay was developed to enable better management of nutrient loads and to predict eutrophication-related problems. The hydrodynamic submodel was calibrated to available tidal data, and the transport submodel was calibrated to a salinity dataset. A 15-month time-series of field data was used together with historical data to calibrate and validate the water-quality submodel. Model simulations suggest that denitrification removes over half the external N inputs with about one-third exported to the open ocean. Approximately 8% of N and 20% of the P loading accumulates in the sediments. Short-term variations due to hydrodynamic effects tend to mask the seasonal cycle in phytoplankton biomass except at inshore localities. The model predictions confirm the field data that indicate that water quality in the western bay is severely affected while the better flushed eastern region remains relatively unaffected. Future increases in nutrient loading due to population pressure are predicted to extend the severely affected region eastwards. Over most of the bay, algal productivity is N-limited except for the western margins where nutrients are saturating and light availability regulates growth. Model hindcasts suggest that system-wide mean algal production has increased by a factor of ten since European settlement.

scholarly journals Groundwater Modelling Quality in the Cold Region of the Athabasca River Basin

2020 ◽  
Author(s):  
Tesfa Worku Meshesha ◽  
Junye Wang ◽  
Nigus Demelash ◽  
Cynthia McClain
Keyword(s):  
Groundwater Quality ◽  
Assessment Tool ◽  
Swat Model ◽  
Surface Water Quality ◽  
Global Scale ◽  
Data Availability ◽  
Nutrient Loads ◽  
Management Scenarios ◽  
Human Welfare ◽  
Scale Modelling

Groundwater is a vital resource for human welfare. However, due to various factors, groundwater pollution is one of the main environmental concerns facing. Yet, it is challenging to simulate groundwater quality dynamics due to the insufficient representation of nutrient percolation processes in the soil and Water Assessment Tool model. The objectives of this study were extending the SWAT module to predict groundwater quality. The results proved a linear relationship between observed and calculated groundwater quality considering No3 and TDS with R2, NSE and PBIAS values in the satisfied ranges, albeit underestimation and overestimation were observed due to limited data availability. These results highlight that nitrate and TDS concentrations and variability in groundwater may used as a tool in surface water quality that have to be assumed for designing adaptive management scenarios. Hence, extended SWAT model could be a powerful tool for future regional to global scale modelling of nutrient loads supporting effective surface and groundwater management.

scholarly journals Long-term influence of climate and experimental eutrophication regimes on phytoplankton blooms

2019 ◽  
Author(s):  
Kateri R. Salk ◽  
Jason J. Venkiteswaran ◽  
Raoul-Marie Couture ◽  
Scott N. Higgins ◽  
Michael J. Paterson ◽  
...  
Keyword(s):  
Climate Change ◽  
Algal Blooms ◽  
Nutrient Loading ◽  
Data Availability ◽  
Change Scenario ◽  
Nutrient Loads ◽  
Phytoplankton Blooms ◽  
Experimental Lakes Area ◽  
Link Type

AbstractPhytoplankton blooms respond to multiple drivers, including climate change and nutrient loading. Here we examine a long-term dataset from Lake 227, a site exposed to a fertilization experiment (1969–present). Changes in nitrogen:phosphorus loading ratios (high N:P, low N:P, P-only) did not impact mean annual biomass, but blooms exhibited substantial inter- and intra-annual variability. We used a process-oriented lake model, MyLake, to successfully reproduce lake physics over 48 years and test if a P-limited model structure predicted blooms. The timing and magnitude of blooms was reproduced during the P-only period but not for the high and low N:P periods, perhaps due to N acquisition pathways not currently included in the model. A model scenario with no experimental fertilization confirmed P loading is the major driver of blooms, while a scenario that removed climate-driven temperature trends showed that increased spring temperatures have exacerbated blooms beyond the effects of fertilization alone.Significance StatementHarmful algal blooms and eutrophication are key water quality issues worldwide. Managing algal blooms is often difficult because multiple drivers, such as climate change and nutrient loading, act concurrently and potentially synergistically. Long-term datasets and simulation models allow us to parse the effects of interacting drivers of blooms. The performance of our model depended on the ratio of nitrogen to phosphorus inputs, suggesting that complex biological dynamics control blooms under variable nutrient loads. We found that blooms were dampened under a “no climate change” scenario, suggesting that the interaction of nutrient loading and increased temperature intensifies blooms. Our results highlight successes and gaps in our ability to model blooms, helping to establish future management recommendations.Data Availability StatementData and metadata will be made available in a GitHub repository (https://github.com/biogeochemistry/Lake-227). Upon manuscript acceptance, the repository will be made publicly available and a DOI will be provided. We request that data users contact the Experimental Lakes Area directly, per their data use policy (http://www.iisd.org/ela/wp-content/uploads/2016/04/Data-Terms-And-Conditions.pdf).

National coastal management challenges and needs

Shore & Beach ◽  
2020 ◽  
pp. 34-43
Author(s):  
Nicole Elko ◽  
Tiffany Roberts Briggs
Keyword(s):  
Coastal Management ◽  
Harmful Algal Blooms ◽  
Algal Blooms ◽  
Local Community ◽  
Extreme Event ◽  
Technical Information ◽  
Interdisciplinary Approach ◽  
Beach Erosion ◽  
The U.S

In partnership with the U.S. Geological Survey Coastal and Marine Hazards and Resources Program (USGS CMHRP) and the U.S. Coastal Research Program (USCRP), the American Shore and Beach Preservation Association (ASBPA) has identified coastal stakeholders’ top coastal management challenges. Informed by two annual surveys, a multiple-choice online poll was conducted in 2019 to evaluate stakeholders’ most pressing problems and needs, including those they felt most ill-equipped to deal with in their day-to-day duties and which tools they most need to address these challenges. The survey also explored where users find technical information and what is missing. From these results, USGS CMHRP, USCRP, ASBPA, and other partners aim to identify research needs that will inform appropriate investments in useful science, tools, and resources to address today’s most pressing coastal challenges. The 15-question survey yielded 134 complete responses with an 80% completion rate from coastal stakeholders such as local community representatives and their industry consultants, state and federal agency representatives, and academics. Respondents from the East, Gulf, West, and Great Lakes coasts, as well as Alaska and Hawaii, were represented. Overall, the prioritized coastal management challenges identified by the survey were: Deteriorating ecosystems leading to reduced (environmental, recreational, economic, storm buffer) functionality, Increasing storminess due to climate change (i.e. more frequent and intense impacts), Coastal flooding, both Sea level rise and associated flooding (e.g. nuisance flooding, king tides), and Combined effects of rainfall and surge on urban flooding (i.e. episodic, short-term), Chronic beach erosion (i.e. high/increasing long-term erosion rates), and Coastal water quality, including harmful algal blooms (e.g. red tide, sargassum). A careful, systematic, and interdisciplinary approach should direct efforts to identify specific research needed to tackle these challenges. A notable shift in priorities from erosion to water-related challenges was recorded from respondents with organizations initially formed for beachfront management. In addition, affiliation-specific and regional responses varied, such as Floridians concern more with harmful algal blooms than any other human and ecosystem health related challenge. The most common need for additional coastal management tools and strategies related to adaptive coastal management to maintain community resilience and continuous storm barriers (dunes, structures), as the top long-term and extreme event needs, respectively. In response to questions about missing information that agencies can provide, respondents frequently mentioned up-to-date data on coastal systems and solutions to challenges as more important than additional tools.

Anticancer Effects & Comparative Study of Thymoquinone, Cordyceps, Spirulina, Ganoderma Lucidium, Poria Cocos, and Lion’s Mane on Human Nasal Cancer Cells (RPMI-2650)

2020 ◽  
pp. 62-78
Author(s):  
سعيد مزعل موازي ◽  
يحيى فائق حسين ◽  
عبد المنعم دولاني ◽  
سيف يوسف عبدالله السويدي
Keyword(s):  
Term Treatment ◽  
Epithelial Cell Line ◽  
Anticancer Effect ◽  
Short Term Treatment ◽  
Poria Cocos ◽  
Nasal Cancer ◽  
Antineoplastic Effect ◽  
Long Term Treatment ◽  
High Concentrations

Recently, many studies have been conducted to discover or improve cancers treatment. The current study aims to investigate the anticancer effect of thymoquinone, cordyceps, spirulina, ganoderma lucidium, poria cocos, and lion’s mane in four different concentrations 4, 8, 16, and 32 ug (equivalent to 1 mg/mL) in two different time treatments (48 and 96 hours) on human nasal epithelial cell line RPMI 2650. By using cell culture cytotoxicity techniques and assay, the highest anticancer effect on RPMI 2650 was obtained by thymoquinone. The lowest anticancer effect was demonstrated by poria cocos and cordyceps. However, these two medications showed higher anticancer effect when given in short-term treatment (48 hours) compared to long-term treatment (96 hours). Ganoderma lucidium and spirulina showed better impact than poria cocos, cordyceps, and lion’s mane in term of cells cytotoxicity. Mild to moderate antineoplastic effect was seen by utilizing lion’s mane treatment compared other drugs. Therefore, adopting a long-term treatment of high concentrations and doses of thymoquinone, cordyceps, spirulina, ganoderma lucidium, poria cocos, and lion’s mane can be more effective in the treatment of nasal cancer. In conclusion, these drugs were found to be a promising cancer remedy; therefore, they can be utilized as alternative treatment for nasal cancer or any other type of cancer therapy.

Water Quality Trends in Hamilton Harbour: 1987 to 1995

1996 ◽  
Vol 31 (3) ◽  
pp. 473-484 ◽  
Author(s):  
Murray N. Charlton ◽  
Robin Le Sage
Keyword(s):  
Algal Blooms ◽  
Action Plan ◽  
Secchi Depth ◽  
Water Clarity ◽  
Nutrient Loads ◽  
Hamilton Harbour ◽  
Near Shore ◽  
The Media ◽  
Park Area ◽  
Water Quality Trends

Abstract A series of water samples and Secchi depth measurements were conducted in Hamilton Harbour between 1987 and 1995. The data indicate little recent improvement in the harbour generally. Detection of real improvements may require high frequency sampling and a more extensive sample grid once a cause for improvement is in place. Some measures, such as chlorophyll and Secchi depth, approach RAP initial goals sometimes during recent years, but algal blooms still occur, which prevent attainment of satisfactory average conditions. The cause of aesthetic improvements in water clarity reported in the media was investigated with sampling along an inshore-offshore transect and intense Secchi measurements in the LaSalle Park area. The data are consistent with a transient clarifying effect of zebra mussels on structures near shore. The need to reduce nutrient loads as recommended in the Remedial Action Plan continues.

Impact of Dursban and Abate on Microbial Numbers and Some Chemical Properties of Standing Ponds

1975 ◽  
Vol 10 (1) ◽  
pp. 33-41 ◽  
Author(s):  
J. Butcher ◽  
M. Boyer ◽  
CD. Fowle
Keyword(s):  
Carbon Dioxide ◽  
Active Ingredient ◽  
Algal Blooms ◽  
Chemical Properties ◽  
Total Carbon ◽  
Dissolved Carbon ◽  
Photosynthetic Productivity ◽  
Dissolved Carbon Dioxide ◽  
Microbial Numbers

Abstract Eleven small ponds, lined with polyethylene, were used to assess the consequences of applications of *DursbanR at 0.004, 0.030, 0.100 and 1.000 ppm and AbateR at 0.025 and 0.100 ppm active ingredient. The treated ponds showed a more pronounced long-term increase in pH and dissolved oxygen and decreasing total and dissolved carbon dioxide in comparison with untreated ponds. Algal blooms were of longer duration in treated ponds than in controls. Total photosynthetic productivity was higher in treated ponds but bacterial numbers did not change significantly. Photosynthetic productivity was estimated by following the changes in total carbon dioxide.

Post-Operative Dysphagia in Anterior Cervical Discectomy and Fusion

2021 ◽  
pp. 000348942110155
Author(s):  
Leonard Haller ◽  
Khush Mehul Kharidia ◽  
Caitlin Bertelsen ◽  
Jeffrey Wang ◽  
Karla O’Dell
Keyword(s):  
Risk Factors ◽  
Medical Records ◽  
Assessment Tool ◽  
Demographic Data ◽  
Anterior Cervical Discectomy ◽  
Cervical Discectomy ◽  
Long Term Follow Up

Objective: We sought to identify risk factors associated with long-term dysphagia, characterize changes in dysphagia over time, and evaluate the incidence of otolaryngology referrals for patients with long-term dysphagia following anterior cervical discectomy with fusion (ACDF). Methods: About 56 patients who underwent ACDF between May 2017 to February 2019 were included in the study. All patients were assessed for dysphagia using the Eating Assessment Tool (EAT-10) survey preoperatively and late postoperatively (≥1 year). Additionally, 28 patients were assessed for dysphagia early postoperatively (2 weeks—3 months). Demographic data, medical comorbidities, intraoperative details, and post-operative otolaryngology referral rates were collected from electronic medical records. Results: Of the 56 patients enrolled, 21 patients (38%) had EAT-10 scores of 3 or more at long-term follow-up. None of the demographics, comorbidities, or surgical factors assessed were associated with long-term dysphagia. Patients who reported no long-term dysphagia had a mean EAT-10 score of 6.9 early postoperatively, while patients with long-term symptoms had a mean score of 18.1 ( P = .006). Of the 21 patients who reported persistent dysphagia symptoms, 3 (14%) received dysphagia testing or otolaryngology referrals post-operatively. Conclusion: Dysphagia is a notable side effect of ACDF surgery, but there are no significant demographics, comorbidities, or surgical risk factors that predict long-term dysphagia. Early postoperative characterization of dysphagia using the EAT-10 questionnaire can help predict long-term symptoms. There is inadequate screening and otolaryngology follow-up for patients with post-ACDF dysphagia.

scholarly journals Development and Verification of the Available Number of Water Intake Days in Ungauged Local Water Source Using the SWAT Model and Flow Recession Curves

Water ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1511
Author(s):  
Jung-Ryel Choi ◽  
Il-Moon Chung ◽  
Se-Jin Jeung ◽  
Kyung-Su Choo ◽  
Cheong-Hyeon Oh ◽  
...  
Keyword(s):  
Water Supply ◽  
Water Intake ◽  
Water Resource Management ◽  
Assessment Tool ◽  
Swat Model ◽  
High Water ◽  
Coefficient Of Determination ◽  
Severe Drought ◽  
Regional Government

Climate change significantly affects water supply availability due to changes in the magnitude and seasonality of runoff and severe drought events. In the case of Korea, despite high water supply ratio, more populations have continued to suffer from restricted regional water supplies. Though Korea enacted the Long-Term Comprehensive Water Resources Plan, a field survey revealed that the regional government organizations limitedly utilized their drought-related data. These limitations present a need for a system that provides a more intuitive drought review, enabling a more prompt response. Thus, this study presents a rating curve for the available number of water intake days per flow, and reviews and calibrates the Soil and Water Assessment Tool (SWAT) model mediators, and found that the coefficient of determination, Nash–Sutcliffe efficiency (NSE), and percent bias (PBIAS) from 2007 to 2011 were at 0.92, 0.84, and 7.2%, respectively, which were “very good” levels. The flow recession curve was proposed after calculating the daily long-term flow and extracted the flow recession trends during days without precipitation. In addition, the SWAT model’s flow data enables the quantitative evaluations of the number of available water intake days without precipitation because of the high hit rate when comparing the available number of water intake days with the limited water supply period near the study watershed. Thus, this study can improve drought response and water resource management plans.

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