The coastal wetlands of southeastern Louisiana are subjected to both elevated nutrients and disturbance. While it is generally accepted that nutrient loading should favor the more flood tolerant species, previous research has not evaluated the effects of nutrient loading on the oligohaline plant community co-dominated by S. patens and S. americanus. A critical data gap in nutrient-loading studies exists in a geographic location subjected to elevated nutrients. Therefore, in this study I sought to isolate the effects phosphorus and nitrogen loading on aboveground plant community dynamics in a co- dominated low salinity marsh at Big Branch Marsh NWR located in Southeastern Louisiana. To improve our understanding of the processes that influence plant
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increasingly elevated with distance downstream. While there is correlative evidence that there is algal growth from elevated nutrients, no one has formally evaluated the algal growth response from nutrient loading. We quantified algal biomass in response to increased nutrient concentrations by sampling benthic algal biomass from natural substrata (rocks) and artificial substrata that also assessed nutrient limitation along a 64 mile stretch from Diversion Dam to the city of Parma. This stretch of river exhibited an increase of in-stream nitrate (0.01 mg/L to 3.40 mg/L) and phosphate (below detection to 0.56 mg/L) from upstream to downstream. Samples were collected from August to October of 2013. We observed low values for algal biomass accrual rate on the unamended artificial substrata in the upper section of the Boise (above Lander Street, Mile 12) of 1.41 – 1.60 mg chlorophyll a/m 2 /day. Accrual rate values increased to 7.03 – 9.88 mg chlorophyll a/m 2 /day near Caldwell (Mile 41), than declined to 6.42 mg
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2) Improvements in water quality can occur through mitigation and best management practices: two drainage areas which were flagged for relative high runoff and loading concerns (Bridge Brooks) in the original Mendum’s Pond Study, and where erosion and parking lot runoff problems were addressed, had major improvements in nutrient loading and were less “flashy” in terms of storm flows.
I n many intensively cultivated areas, surface and ground waters suffer from eutrophication and deterioration of the water quality. To improve the environmental protection actions of agriculture, EU countries have adopted common legislation, such as the Nitrate Directive and the Water Framework Directive, which set limits to the use of manure and aim at good ecological state of waters by 2015, respectively. Moreover, different voluntary measures and environmental schemes are being supported financially by EU and national governments to reduce agricultural nutrient loading and eutrophication, for instance by optimizing phosphorus (P) and nitrogen (N) fertilization, controlling erosion and promoting the establishment of buffer zones and wetlands. Yet, good ecological state appears to be unattainable in many agriculturally loaded water bodies in the near future. Former accumulation of nutrients in soils and sediments retards the recovery of waters, implementation of environmentally friendly measures may be inadequate, or the measures themselves are inefficient. There is an obvious need for novel methods and new techniques that speed up the load reduction and the recovery of different types of water bodies and that could be easily adopted by farmers and put into practice by other stakeholders in the river basins.
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Smith and Cave (2012) measured both TON (Total Oxidised Nitrogen) and DIP (Dissolved Inorganic Phosphorus) at both springs in Kinvara (KE and KW) with results showing that Kinvara is a strong source of fixed nitrogen into Kinvara Bay. This is important as nitrogen tends to be the limiting nutrient in the marine environment rather than phosphorus (which is generally the limiting nutrient in freshwater systems). TON concentrations from KE were measured up to 1 mg/l while water from KW tended to have approximately half that concentration. Neither spring at Kinvara, however, were considered as significant sources of DIP into the bay. Low concentrations of DIP compared to the DIP concentration in Galway Bay indicated that Kinvara may actually be a sink of DIP rather than a source (Smith and Cave, 2012). The relatively high concentration of N compared to P at the Kinvara springs is a common occurrence in most SGD scenarios as the removal processes of P in groundwater are typically more efficient than those for N (Slomp and Van Cappellen, 2004). The average N:P ratio of rivers discharging into the sea is approximately 18:1 (Smith et al., 2003) whereas SGD N:P ratios tend to be higher. For example, ratios of 18:1 (Swarzenski et al., 2001), 190:1 (Wu et al., 2013) and 660:1 (Kelly and Moran, 2002) have been reported, with higher ratios commonly associated with sewage contamination within the aquifer. The ratios found at the Kinvara springs are moderate in comparison (45:1 for KW, 82:1 for KE), likely due to the relatively high mass flux which occurs within the karst aquifer, and the large component of river water which feeds it. Further out in Kinvara Bay, the N:P ratio is likely to increase due to the contribution of untreated sewage.
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0.0164, 1.013 and 0.0124 mg/L, respectively, that were measured in lake water during the field portion of the studies. One treatment was the control to which no N or P was added. Thus, there were a total of 75 flasks (25 treatment combinations with 3 replicates each). The five concentrations of N and P were selected in combination for nutrient addition (Supplemental Materials, Table S2). Bioassays were conducted either with consortia of plank- ton or with filtered water F and flasks were inoculated with either a single species of cyanobacteria or a consor- tium of cells isolated from Lake Diefenbaker water. Qualitative microscopical analysis revealed five algal species in surface and mid water of Lake Diefenbaker sampled on September 29 and 30, 2008 (Figure 2). At site 4, for which a cyanobacteria bloom was reported in October 2007, the dominant algae species was Anabena circinalis in surface water. Furthermore, Woronichinia naegeliana at this location and in surface and middle layer lake water at site 5. None of the other sites (1, 2, 3, 6 and 7) contained these species. Furthermore, three uni- dentified species occurred at most of the locations. While no quantitative assessments of algal abundance at the laboratory were made due to lack of appropriate sample preservation, the qualitative assessment indicated that Anabaena sp. was the dominant algal species.
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Longer-term improvements center on the incorporation of a mechanistic model for describing biogeochemical pro- cesses in the water column and sediment. This allows for further analysis of individual processes and their interplay (plant uptake, sedimentation, benthic processes, denitrifica- tion). This will involve a change to a temporal resolution that matches the requirements of the description of the biogeo- chemical processes (day, week, month). Mechanistic model- ing of in-stream processes with shorter time steps requires a further refinement of the processes on the land, i.e., the tem- poral distribution of fertilizer application, manure spreading and grazing. This will also allow us to analyze the delay be- tween rainfall events causing runoff and the discharge to the surface water. Also, such mechanistic models require a deliv- ery and in-stream model that distinguishes different nutrient forms.
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In Finland, the ﬁrst large-scale efforts to control nutrient loading from agriculture got under way with the introduction of the EU Agri-Environmental Program in 1995. We examined whether these efforts have decreased agricultural nutrient losses and improved the quality of receiving waters. To do so we used monitoring data on ﬂuxes of nutrients and total suspended solids in agricultural catchments in 1990–2004 and on the water quality of agriculturally loaded rivers, lakes and estuaries in 1990–2005. No clear reduction in loading or improvement in water quality was detected. Hydrological ﬂuctuations do not seem to have eclipsed the effects of the mea- sures taken, since there was no systematic pattern in runoff in the period studied. The apparent inefﬁciency of the measures taken may be due to the large nutrient reserves of the soil, which slowed down nutrient reductions within the period studied. Simultaneous changes in agricultural production (e.g. regional specialisation) and in climate may also have counteracted the effects of agri-environmental measures. The actions to reduce agricultural loading might have been more successful had they focused speciﬁcally on the areas and actions that contribute most to the current loading.
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et al., 1995). Geese predominantly graze around ponds, es- pecially with broods and when they are moulting their flight feathers; the ponds are essential to escape predation. As a result, pond perimeters in areas used heavily by geese are notably mossy, brown, and muddy due to the heavy localized grazing. At these pond margins and indeed throughout the catchment, geese have the potential to influence freshwater ecosystems indirectly through this mobilization of nutrients. While considerable research has outlined the effects of grazing and grubbing on terrestrial habitats, very few stud- ies have focused on the associated freshwater habitats. Shal- low freshwaters are highly connected to their catchments by a high surface area to volume ratio (Rautio et al., 2011). Thus, ponds are very susceptible to habitat changes within the catchment, from increased terrestrial organic matter flow- ing into the pond due to heavily grazed pond edges, through the decomposition of goose droppings, and through sedi- ment bioturbation that brings nutrients back into suspen- sion. Increased terrestrial organic matter leads to a more bacteria-based production rather than photosynthetic produc- tion (Ask et al., 2009). On the other hand, increased nutri- ents can cause shifts in trophic status and increased phyto- plankton productivity, as demonstrated in nutrient addition experiments (Schindler et al., 2008) or in systems where seabirds act as bio-vectors transferring marine nutrients to ponds (Michelutti et al., 2009). Arctic-breeding geese could be acting as bio-vectors, causing an accumulation of terres- trial nutrients in ponds, but so far there is little published in- formation on rates of nutrient loading into freshwater sys- tems in the Arctic (Dessborn et al., 2016).
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Of all the in-depth watershed nutrient budget measurements and modeling efforts that have been attempted in NH none have included an in depth analysis of septic system influences from newly built and legacy septic systems. The current project expanded on an existing study of septic system hydrology to evaluate the use of emerging contaminant markers such as caffeine and triclosan to assess septic influence on water quality.
Neither zonal geranium nor petunia cuttings soluble sugar concentrations were affected by nutrient treatment. These results are contradictory to the 2009 study by Zerche and Druege reporting N supply (low, adequate, and high N rates based on biweekly soil sample analysis results) affected carbohydrate levels in poinsettia cuttings. The observation that soluble carbohydrate levels in the leaf lamina accumulated during rooting is likely related to depletion during shipping. Depletion is thought to up-regulate genes involved in photosynthesis, remobilization, and carbohydrate export (Koch, 1996). Our results in petunia, with the exception of sucrose, support research by Ahkami et al (2008). Glucose and fructose levels reached their highest before the emergence of roots. Petunia cutting sucrose levels in this study do not appear to have been depleted during shipping and did not have the same response as the other soluble carbohydrates.
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A nutrient budget takes into account all the nutrient inputs on a farm and all those removed from the land. The most obvious source of nutrients in this situation is fertilizer, but this is only part of the picture. Other inputs come with rainfall, in supplements brought on to the farm and in effluent - either farm or dairy factory - spread on the land. In addition, nutrients can be moved around the farm - from an area used for growing silage to the area used to feed it out, from paddock to raceway, and within paddocks in dung and urine patches. In this paper, nutrient budget is discussed as a useful management tool that quantifies the amount of nutrients imported to and exported from a system. Nutrient budget is an important tool for effective crop yields and soil management. The paper therefore recommends among others that nutrient budgeting is a way of helping land owners choose and implement best management practices (BMPs) that will reduce the likelihood of nutrient surpluses, while maintaining soil productivity. Having a balanced nutrient budget for an agricultural production will help to avoid unnecessary production costs and greatly reduce pollution potential from surplus nutrients.
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Floodplains and riparian zones are known to be important locations for sediment storage and nutrient transformations. While extensive research has been conducted on the capacity for riparian zones to buffer sediment and nutrient loads in natural systems, we know relatively little about the water quality function of floodplains in restored streams. Restoration practices that seek to improve the function of urban streams are often constrained by nearby infrastructure and competing uses for land near the stream, including roads, buildings and utilities. Recent efforts throughout many major urban centers are also setting goals of increasing community engagement and accessibility through establishment of greenways, parks and nearby recreation. Collectively, these constraints in urban settings make floodplain reconnection to improve water quality and decrease flood pulses a challenging goal. Therefore, the goal of this research was to characterize and quantify the capacity for water quality improvements via retention of sediment, nitrogen and phosphorus in these systems.
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Chemical preservatives in foods are nowadays added at lower concentrations. How- ever, this may allow survival of bacterial cells and induce increased resistance to var- ious preservatives. In this study, the effects of growth in NaCl (10% or 15%) on sur- vival of Staphylococcus aureus strains in various chemical and physical preservatives were investigated. Growth of the strains for 20 h at 37˚C in nutrient broth containing 10% NaCl enhanced survival in chemical preservatives (e.g. nutrient broth contain- ing 20% NaCl, or 0.3% thyme extract, or 0.1% ascorbic acid). Growth at 37˚C for 20 h in nutrient broth containing 15% NaCl or for 5 d in nutrient broth containing 10% NaCl greatly enhanced survival of the strains in the tested preservatives. For survival at low temperature (5˚C) (physical preservative), cells grown at 37˚C for 20 h in nu- trient broth containing 10% NaCl were not more tolerant to low temperature. Growth of the strains at 37˚C for 20 h in nutrient broth containing 15% NaCl or for 5 d in nutrient broth containing 10% NaCl only slightly increased the survival of cells at low temperature.
Cassava (Manihot esculanta Crantz) is a major staple in Nigeria. It is popularly consumed in various forms in- cluding gari, fufu and lafun and tapioca . The cassava root is energy-dense, containing 80% to 90% carbohy- drate on a dry weight basis  and is a predominantly starchy food . Grown in more than 90 countries, it ranks as the 6th most important source of energy in hu- man diets on a worldwide basis and as the 4th supplier of energy after rice, sugar, and corn/maize . However, it is low in protein, at 1% to 3% on a dry matter basis . Cassava has the lowest protein:energy ratio of any staple crop; the protein content among common cassava culti- vars is typically only 1% . This is of nutritional im- portance for populations that depend largely on cassava products for their energy needs. An observational study in Kenya and Nigeria  showed that consuming cassava as a staple food placed children 2 - 5 years old at risk for inadequate protein intake. In addition cassava contains toxic substances such as cyanide and antinutrients, such as phytate, fiber, nitrate, polyphenols, oxalate, and sa- ponins that can reduce nutrient bioavailability [2,8]. Hence, improving the nutritional value of cassava food products becomes a necessary intervention in such areas.
Tangential flow filtration was used to isolate and concentrate DON more than tenfold from three river locations within the Neuse River basin using. The effect of this HMW riverine DON on estuarine phytoplankton and bacteria was tested using a seasonal series of nutrient addition bioassays. Overall, phytoplankton and bacteria did not significantly respond to the HMW DON, even at time scales of two to three weeks. When increases in productivity and biomass did occur, it was quite small compared with the response to DIN. Bulk DON and DOC concentrations changed little, suggesting that bioavailable compounds added in the experimental treatments had low concentrations and were turned over quite rapidly. Phytoplankton taxa, as measured by diagnostic photopigments, did not appear to be selectively enhanced by the HMW DON
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On wet and windy days, the inclined cables of cable-stayed bridges may ex- perience a large amplitude oscillation known as Rain-Wind-Induced Vibration (RWIV). It has previously been shown by ‘in-situ’ and wind-tunnel studies that the formation of rain-water accumulations or ‘rivulets’ at approximately the separation points of the external aerodynamic flow field and the resulting effect that these rivulets have on this field may be one of the primary mechanisms for RWIV. A numerical method has been developed to undertake simulations of certain aspects of RWIV, in particular, rivulet formation and evolution. Specif- ically a two-dimensional model for the evolution of a thin film of water on the outer surface of a horizontal circular cylinder subject to the pressure and shear forces that result from the external flow field is presented. Numerical simula- tions of the resulting evolution equation using a bespoke pseudo-spectral solver capture the formation of two-dimensional rivulets, the geometry, location and growth rate of which are all in good agreement with previous studies. Exami- nations of how the distribution and magnitude of aerodynamic loading and the Reynolds number influence the rivulet temporal evolution are undertaken, the results of which indicate that while all three affect the temporal evolution, the distribution of the loading has the greatest effect.
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Understanding the biogeochemical processes acting to transform nutrients within the sediment and regulate transfer between the sediment and the overlying water- column is a complex scientific discipline. Spatially, variations in such processes can be observed from the geographic- (governed by land-use and variations in seasonal extremes; Lehner and Döll, 2004) to the micro-scale (Downing and Rath, 1988). Similarly, temporal variations can occur over thousands of years (e.g. natural aging of a lake; Engstrom et al., 2000) or in the space of a few minutes (Froelich, 1988). Gaining a true comprehension of such variation is crucial to our ability to understand the effects of anthropogenic pressures on the aquatic environment. However, our ability to realise this goal is limited by our capacity to observe the spatial and temporal dynamics of the system, and by our lack of knowledge concerning key processes acting to regulate it. This discussion aims to highlight the advances provided by this body of work against the background of current knowledge of the spatial and temporal variations in sediment nutrient processes and of the importance of benthic/pelagic biologically mediated nutrient cycling in regulating such processes. However, the advancements to the methodologies available for quantifying sediment phosphorus content and benthic microalgae in the context of the current state of the art, are first discussed.
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Even though there are considerable challenges in estimating the total benefits of reduced eutrophication in monetary terms, the empirical literature on valuation of water quality improvements is extensive (see e.g. Freeman 1995, Wilson & Carpenter 1999). In our application, we have relied on benefit estimates available from a previ- ous contingent valuation study by Söderqvist (1996), who carried out a valuation project of the Baltic drainage basin as part of an EU Environmental Research Program (see also Turner et al. 1999). The study indicated that inhabitants in the region place a significant value on the benefits: willingness to pay for reducing eutrophication in 20 years from its current level to a level that the Baltic Sea can sustain resulted in a basin wide estimate for total benefits of about 55 000 million Euro. As the environ- mental problem is caused by the accumulated stocks of nutrients (i.e. nutrient mass = concentration times volume) rather than immediate flows, we seek to relate the willingness to pay measure for avoiding eutrophication to a specific reduction in the nutrient stocks. This is consistent with many other situations where ecosystems are altered by the release of long-lived pollutants. In our model, the benefits are attributed to the state of the water ecosystem as measured by nutrient mass.
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analyses and current sweeping frequencies, it is recommended at a minimum downtown streets are swept weekly. However, factors including sweeper and operator efficiencies, overhanging tree canopy, and typical durations between storm events should also be considered (Selbig and Bannerman, 2007). Piedmont municipalities may also consider sweeping more frequently during autumn. In contrast, Coastal Plain municipalities may be better served if sweeping was more frequent during winter. For these ecoregions, leaf fall occurs during these seasons, and pollutant loads collected during these seasons at these locations were the largest. Nutrient loads in street sweepings can be estimated using the pollutant concentrations that were normalized by the watershed’s curb length as well as the draft model discussed in Section 1.6 (Kalinosky et al., 2014) which could also be used to establish sweeping frequencies and optimize sweeping routes.
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