Phosphorus loading reductions needed to control blue-green algal blooms in Lake Mendota

1998 ◽  
Vol 55 (5) ◽  
pp. 1169-1178 ◽  
Author(s):  
Richard C Lathrop ◽  
Stephen R Carpenter ◽  
Craig A Stow ◽  
Patricia A Soranno ◽  
John C Panuska
Keyword(s):  
Algal Blooms ◽  
Management Practices ◽  
Phosphorus Loading ◽  
Balance Model ◽  
Load Reduction ◽  
Lake Water Quality ◽  
Time Step ◽  
Data Set ◽  
Lake Mendota ◽  
Green Algal

We evaluated the reductions in P loading needed to control blue-green algal blooms in Lake Mendota, Wisconsin. After developing a 21-year loading data set, we used a P mass balance model expressed as a difference equation with an annual time step indexed from mid-April. We defined and estimated a loss parameter lambda as the proportion of the lake's April P concentration lost through sedimentation and outflow during the following year. Using the distribution of annual lambda 's and input loadings, we predicted the steady-state distribution of April P concentrations that would result from scenarios of altered inputs due to changes in management practices. These results were then linked to the probability of summer blue-green algal blooms. For no load reduction, the probability of a bloom (>2 mg algae ·L-1) on any summer day is about 60%. This probability decreases to 20% with a load reduction of 50%. Our approach illustrates how managers can consider reducing the frequency of extreme events like algal blooms, which may correspond more to the public's perception of lake water quality than average conditions.

Internal phosphorus loading in Lake Mendota: response to external loads and weather

1997 ◽  
Vol 54 (8) ◽  
pp. 1883-1893 ◽  
Author(s):  
P A Soranno ◽  
S R Carpenter ◽  
R C Lathrop
Keyword(s):  
Interannual Variability ◽  
Standing Stock ◽  
Internal Loading ◽  
Phosphorus Loading ◽  
External Loading ◽  
Lake Mendota ◽  
Water Column Stability ◽  
Green Algal ◽  
External Loads ◽  
P Budget

We quantified summer internal phosphorus (P) loads and all the major P fluxes in Lake Mendota, Wisconsin, a deep stratified eutrophic lake, during two summers of contrasting external loads to determine (i) whether internal loading by entrainment (mixing at the thermocline) is a significant part of the epilimnetic P budget and (ii) what factors lead to interannual variability in internal loading. We estimated variables for the P budget weekly (standing stock, sedimentation) or daily (outflow, inflow, and entrainment) during a summer of average runoff (1992) and one of higher than average runoff (1993). Entrainment, estimated by calculating the amount of P transported into the epilimnion after the thermocline deepened following storms, was about 10 times higher than external loading during 1992, but was about equal to external loading during 1993. When entrainment was included, the epilimnetic P budget balanced. Interannual variability in internal loading appears to be due to a combination of water column stability, weather, and the P levels accumulated in the metalimnion. External loads to the epilimnion during summer 1993 were much higher than in 1992 (7.0 and 0.9 mg P ·m-2 ·day-1, respectively); however, total loads (internal + external) were more similar (12.5 and 7.8 mg P ·m-2 cdot day-1 in 1993 and 1992, respectively). Although summer chlorophyll concentrations were similar in the two summers, blue-green algal biomass in 1993 was about double that in 1992.

Biology and Management of Inland Striped Bass and Hybrid Striped Bass

2013 ◽  
Keyword(s):  
Water Quality ◽  
South Carolina ◽  
Dissolved Oxygen ◽  
Striped Bass ◽  
Algal Blooms ◽  
Management Practices ◽  
Nutrient Loading ◽  
Phosphorus Loading ◽  
Quality Model ◽  
Habitat Temperature

<em>Abstract</em>.—A CE-QUAL-W2 water quality model was used to characterize the availability of striped bass <em>Morone saxatilis</em> habitat in Lake Greenwood, South Carolina, during 2004 and 2005. Although the lake has a productive fishery, water quality and aquatic habitat are affected by nutrient loading, algal blooms, and extensive oxygen depletion in the bottom waters. The main objectives were to characterize habitat availability and predict the implications of a change in phosphorus loading from the Saluda and Reedy rivers. The baseline scenario of the model showed that habitat was most critical during July and August, when as little of 5% of the reservoir contained tolerable habitat (temperature <28°C and dissolved oxygen >2 mg/L). Favorable habitat (temperature <25°C and dissolved oxygen >2 mg/L) was usually absent for most of July and August. Pulses of higher inflow or freshets produced short-term increases in tolerable habitat, especially in the upper end of the reservoir. Phosphorus-loading scenarios predicted that large reductions (50% or more) would be required to improve habitat substantially during midsummer. For the manager of a striped bass fishery, water quality models can be useful tools for evaluating habitat, especially under marginal conditions, and for predicting the impact of altered water management practices.

Factors affecting the timing of surface scums and epilimnetic blooms of blue-green algae in a eutrophic lake

1997 ◽  
Vol 54 (9) ◽  
pp. 1965-1975 ◽  
Author(s):  
P A Soranno
Keyword(s):  
Atmospheric Pressure ◽  
Algal Blooms ◽  
Algal Biomass ◽  
Eutrophic Lake ◽  
Lake Surface ◽  
Factors Affecting ◽  
Blue Green Algae ◽  
Lake Mendota ◽  
Green Algal ◽  
Using Data

Blue-green algal blooms, which can occur mixed throughout the epilimnion or as scums at the lake surface, develop in response to a variety of factors. However, it is still unclear what conditions suggest that blooms are imminent or how far in advance blooms can be forecast. I assessed the predictability of surface scums and epilimnetic blooms from limnological, physical, and meteorological variables using data sampled daily during summer and fall 1993 in Lake Mendota, Wisconsin. Daily chlorophyll a (a measure of blue-green algal biomass) was correlated to some weather, physical, and grazing variables at lags ranging from 0 to 9 days. Conditions immediately preceding surface scums were variable, making predictions difficult. However, during surface scums, Secchi disk depth, wind velocity, atmospheric pressure, and precipitation were significantly different than when the scums were absent. Based on predictors examined in this study, I developed criteria that identify the conditions sufficient for scums to form. In Lake Mendota, conditions sufficient for surface scum formation (proper weather and water column conditions and a pre-existing algal population) occur much more often than scums are observed. This study shows the importance of weather in determining both epilimnetic blue-green algal biomass and surface scum formation.

How Can We Use Fluorescence And Artificial Intelligence To Better Control Blue-Green Algal Blooms?

2018 ◽  
Author(s):  
Edoardo Bertone ◽  
Michele A. Burford ◽  
David P. Hamilton
Keyword(s):  
Artificial Intelligence ◽  
Algal Blooms ◽  
Green Algal

Climate resilience in rural Zambia: evaluating farmers’ response to El Niño-induced drought

2021 ◽  
pp. 1-23
Author(s):  
Federica Alfani ◽  
Aslihan Arslan ◽  
Nancy McCarthy ◽  
Romina Cavatassi ◽  
Nicholas Sitko
Keyword(s):  
El Niño ◽  
Management Practices ◽  
Unobserved Heterogeneity ◽  
El Nino ◽  
Control Measures ◽  
Data Set ◽  
Climate Resilience ◽  
Diversification Strategies ◽  
Household Incomes ◽  
Rural Zambia

Abstract This paper aims at identifying whether and how sustainable land management practices and livelihood diversification strategies have contributed to moderating the impacts of the El Niño-related drought in Zambia. This is done using a specifically designed survey called the El Niño Impact Assessment Survey, which is combined with the Rural Agricultural Livelihoods Surveys, as well as high resolution rainfall data at the ward level over 34 years. This unique panel data set allows us to control for the time-invariant unobserved heterogeneity to understand the impacts of shocks like El Niño, which are expected to become more frequent and severe as a result of climate change. We find that maize yields were substantially reduced and that household incomes were only partially protected from the shock thanks to diversification strategies. Mechanical erosion control measures and livestock diversification emerge as the only strategies that provided yield and income benefits under weather shock.

A NEW TECHNIQUE ESTIMATING LOCATION OF MEAN JOINT CENTERS OF ROTATION WITH ASSOCIATED DISPERSIONS AND ASSESSING TO FUNCTIONAL COORDINATE SYSTEM OF MOVING LIMB SEGMENTS

2006 ◽  
Vol 06 (04) ◽  
pp. 373-384
Author(s):  
ERIC BERTHONNAUD ◽  
JOANNÈS DIMNET
Keyword(s):  
Numerical Technique ◽  
New Technique ◽  
Helical Axis ◽  
Joint Movement ◽  
Time Step ◽  
Data Set ◽  
Minimization Procedure ◽  
A New Technique ◽  
Joint Center

Joint centers are obtained from data treatment of a set of markers placed on the skin of moving limb segments. Finite helical axis (FHA) parameters are calculated between time step increments. Artifacts associated with nonrigid body movements of markers entail ill-determination of FHA parameters. Mean centers of rotation may be calculated over the whole movement, when human articulations are likened to spherical joints. They are obtained using numerical technique, defining point with minimal amplitude, during joint movement. A new technique is presented. Hip, knee, and ankle mean centers of rotation are calculated. Their locations depend on the application of two constraints. The joint center must be located next to the estimated geometric joint center. The geometric joint center may migrate inside a cube of possible location. This cube of error is located with respect to the marker coordinate systems of the two limb segments adjacent to the joint. Its position depends on the joint and the patient height, and is obtained from a stereoradiographic study with specimen. The mean position of joint center and corresponding dispersion are obtained through a minimization procedure. The location of mean joint center is compared with the position of FHA calculated between different sequential steps: time sequential step, and rotation sequential step where a minimal rotation amplitude is imposed between two joint positions. Sticks are drawn connecting adjacent mean centers. The animation of stick diagrams allows clinical users to estimate the displacements of long bones (femur and tibia) from the whole data set.

scholarly journals Combining efficiency and innovation to enhance performance: Evidence from firms in emerging economies

2018 ◽  
pp. 1-17 ◽  
Author(s):  
Xiaowen Tian ◽  
Vai Io Lo ◽  
Xiaoxuan Zhai
Keyword(s):  
Emerging Economies ◽  
Best Management Practices ◽  
Management Practices ◽  
Data Set ◽  
Best Management ◽  
The World Bank ◽  
Combining Efficiency ◽  
Low Levels ◽  
Enhance Efficiency ◽  
Innovation Processes

AbstractThis paper extends the resource-capability-based view in strategic management and discusses the capabilities for the firms to stay competitive in emerging economies. Faced with low levels of efficiency, technology, and skills, firms in emerging economies need to implement best management practices to overcome operational inefficiency while engage in innovation processes to address new opportunities. They have to develop the capabilities to enhance efficiency, the capabilities to undertake innovation, and the synthesis capabilities to combine the two to keep rivals at bay. The paper tests hypotheses against a data set of more than 20,000 firms from 36 emerging economies provided by the World Bank in 2012–2015 and finds strong evidence to support the arguments. The paper finds that the three sets of capabilities are positively related to productivity and, through it, financial performance.

scholarly journals The Past, Present, and Future of Tuna at Lake Moāwhitu: Drawing on the two knowledge baskets of Mātauranga Māori and Western Science

2021 ◽  
Author(s):  
Russleigh Parai
Keyword(s):  
Algal Blooms ◽  
Human Impacts ◽  
Anthropogenic Impacts ◽  
Land Use Changes ◽  
Environmental Dna ◽  
Western Science ◽  
Lake Water Quality ◽  
Dna Metabarcoding ◽  
Remedial Intervention ◽  
Life Force

<p><b>Knowledge generated through experience and understanding relies on the senses, one of which is listening. This thesis provides an opportunity to hear the diminishing voice of tuna utilizing paleolimnological techniques and our natural senses through traditional Indigenous methodologies in order to track the presence of tuna back in time. </b></p> <p>This study provides historical environmental context of Lake Moāwhitu catchment (Rangitoto ki te Tonga) as a once significant mahinga kai site for manawhenua, Ngāti Koata. The strong connection to place is not lost on Ngāti Koata despite for many their geographic detachment to their turangawaewae. They hear the voice of tuna calling them back to sustain them as they have sustained Māori from the beginning of time. Now considered wāhi tapu due to significant degradation, Moāwhitu is currently undergoing remedial intervention by Ngāti Koata, DoC, Lakes380 and stakeholders to restore the mauri (life force) of the Lake and adjacent wetland ecosystem.</p> <p>Drawing from two distinct knowledge streams of western science and mātauranga Māori, this study draws new (on-site) understandings about the anthropogenic impacts on tuna as well as their status and relationship as tuākana (older sibling) to Māori. Through this journey a ‘te ao Māori’ (Māori worldview) is explored, revealing a historically healthy and abundant tuna population and thriving tuākana-teina relationship up until recent decades. This information complements the environmental reconstruction derived from western science methods applied to a lake Moawhitu sediment core spanning the last 1000 years or so. Through a combination of palynology, hyperspectral scanning and bacterial environmental DNA metabarcoding, it is clear that lake water quality remained high despite various historical land cover and land use changes, until recent decades when deteriorating quality has accompanied a rise in cyanobacteria and toxic algal blooms. These changes appear to coincide with intensified pastoralism accompanying draining of the lake and fringing wetlands since the mid-twentieth century. How tuna have endured these recent human impacts and why their survival and sustainability is important to Aotearoa today is at the heart of this thesis which seeks to explore how two vastly different knowledge streams converge and navigate unchartered waters. The two knowledge baskets (with their respective world views) are held up for the reader to view and consider what an effective collaborative partnership looks like by recognising basic intrinsic values of respect, reciprocity and kindness. The challenge remains to draw out the very best of people (he tangata) as a way to bring about urgent regenerative solutions for our tuākana, tuna, and in turn humanity itself.</p>

scholarly journals The effect of talent management practices on employee turnover intention in the Information and Communication Technologies (ICTs) sector: case of Jordan

2020 ◽  
Vol 18 (4) ◽  
pp. 59-71
Author(s):  
Maha Al-Dalahmeh ◽  
Mária Héder-Rima ◽  
Krisztina Dajnoki
Keyword(s):  
Information And Communication Technologies ◽  
Turnover Intention ◽  
Management Practices ◽  
Communication Technologies ◽  
Intention To Leave ◽  
Talent Management ◽  
Data Set ◽  
Employee Turnover Intention ◽  
Information And Communication ◽  
Ict Companies

This research aims to examine the intention of talented employees to leave an organization and discover how talent management practices could affect employee intention to leave an organization. This paper`s framework intends to outline the relationship between variables to present the idea of talent management practices and employee retention. The hypothesis was tested using a survey data set of 210 questionnaires collected from employees working in 82 ICT companies in Jordan to attain the research objectives. The collected data were analyzed using the SPSS program, and EMOS program, and basic and initial statistical techniques were applied. The results show that talent management practices significantly affect employee intention to leave an organization. Accordingly, whenever firms applied talent management practices, employee intention to leave decreases. The results demonstrated that attracting talented employees has emerged to have the strongest effect on decreasing employee intention to leave; however, developing and rewarding talented employees was revealed to have the lowest effect. Thus, the ICT firms’ managers have to generate specific training programs to reward and develop talented employees. AcknowledgmentThe publication is supported by the EU-funded Hungarian grant EFOP-3.6.3.-VEKOP-16-2017-00007 for the project entitled “From Talent to Young Researchers” – Supporting the Career-developing Activities of Researchers in Higher Education”.

scholarly journals Estimation of Leachate Generated from Zimbabwe’s Municipal Solid Wastes (MSW) Landfills using a Simple Stochastic Water Balance Model

2018 ◽  
pp. 40-50
Author(s):  
Andile B. Maqhuzu ◽  
Kunio Yoshikawa ◽  
Fumitake Takahashi
Keyword(s):  
Water Balance ◽  
Waste Management ◽  
Management Practices ◽  
Balance Model ◽  
Probability Models ◽  
Municipal Solid Wastes ◽  
Predominant Component ◽  
Indiscriminate Disposal ◽  
Waste Management Practices ◽  
The Impact

Landfilling remains the predominant component in the waste management hierarchy of most developing nations. The adoption of emerging waste management technologies and the use of recycling or composting is still in its infancy. Among several inadequacies of current waste management practices in Zimbabwe is the absence of sanitary disposal of municipal solid waste (MSW) in landfills. As a result, the leachate generation rate and leachate characteristics are not routinely monitored. Such information is essential when assessing the impact of leachate on ground and surface water or a facility to which the leachate can be conveyed. Indiscriminate disposal of MSW at unsanitary dumpsites poses a double threat as the discharge of hazardous leachate to potable water sources and emissionsof toxic odours leads to further environmental degradation. Poor waste management practices are compounded by a lack of financial resources and technical capabilities. The financial incapacitation of local authorities is reflected in the fact that there are no reliable statistics on MSW generation and disposal. This lack of comprehensive data has hampered the quantification of MSW and resultant leachate. Therefore, the objectives of this study are twofold. First, we seek to predict the annual quantity of landfilled MSW, and secondly to quantify the leachate flow from Zimbabwe’s landfills. Both were achieved through the use of probability models and a stochastic water balance method supported by 10,000 Monte Carlo iterations. The calculated 90%confidence interval indicates that 13-16 million tonsof MSW havebeen landfilled, with about 41-128 million m3of leachate released since 1980. This is equivalent to a mean of 414,212tons a-1of landfilled MSW and 2.2 millionm3a-1of leachate generated, respectively.

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