Water Stocks Research Articles

Impact on the replacement of Phe by Trp in a short fragment of Aβ amyloid peptide on the formation of fibrils

Aβ(16-22) (Ac-KLVFFAE-NH(2) ) is one of the shortest amyloid fibril-forming sequences identified in β-amyloid peptide. At neutral pH, the peptide forms fibrils in the concentration range of 0.2-2.0 mM after ≥ 10 days of incubation. Structures of the fibrils proposed based on solid-state NMR and MD simulations studies suggest antiparallel arrangement of β-strands and aromatic interactions between the Phe residues. In an effort to examine the role of aromatic interactions between two Phe residues in Aβ(16-22) , we have studied the self-assembly of Aβ(16-22) (AβFF) and two of its variants, Ac-KLVFWAE-NH(2) (AβFW) and Ac-KLVWFAE-NH(2) (AβWF). The peptides were dissolved in methanol (MeOH) at a concentration of 1 mM and in water (AβFW and AβWF, 1 mM; AβFF, 330 µM). Peptide solutions (100 µM) were prepared in 50 mM sodium phosphate buffer at pH 7 by diluting from MeOH and water stock solutions. AβFW forms amyloid-like fibrils immediately from MeOH, as indicated by atomic force microscopy. Dilution of AβFW into phosphate buffer from stock solution prepared in MeOH results in fibrils, but with different morphology and dimensions. The secondary structure potentiated by MeOH seems to be important for the self-assembly of AβFW, as fibrils are not formed from water where the peptide is unordered. On the other hand, AβFF and AβWF do not form amyloid fibrils rapidly from any of the solvents used for dissolution. However, drying of AβWF from MeOH on mica surface gives rod-like and fibrous structures. Our study indicates that positioning of the aromatic residues F and W has an important role to play in promoting self-assembly of the Aβ(16-22) peptides.

Discriminating bluemouth, Helicolenus dactylopterus (Pisces: Sebastidae), stocks in Portuguese waters by means of otolith shape analysis

The understanding of the stock structure of a species is essential to effectively manage fisheries. Otolith shape analysis has been successfully applied in stock identification using the elliptic Fourier analysis. This method was used to assess possible differences in the otolith shape of Helicolenus dactylopterus caught around the Azores, Madeira and mainland Portugal. A total of 294 individuals ranging from 23 to 29 cm in total length, equally distributed by sex and area, were analysed. The multivariate analysis of variance performed on the otolith normalized elliptic Fourier descriptors (NEFDs) revealed significant differences for both area and sex, but no interaction was found between the two factors. In the canonical discriminant analysis an overall classification success of 69.4% and 66.7% was achieved for females and males respectively. These results suggest the usefulness of otolith shape analysis for stock differentiation of bluemouth from Portuguese waters.

Limnology of Macrobrachium amazonicum grow-out ponds subject to high inflow of nutrient-rich water and different stocking and harvest management

We evaluated the water characteristics and particle sedimentation in Macrobrachium amazonicum (Heller 1862) grow-out ponds supplied with a high inflow of nutrient-rich water. Prawns were subject to different stocking and harvesting strategies: upper-graded juveniles, lower-graded juveniles, non-graded juveniles+selective harvesting and traditional farming (non-grading juveniles and total harvest only). Dissolved oxygen, afternoon N-ammonia and N-nitrate and soluble orthophosphate were lower in the ponds in comparison with inflow water through the rearing cycle. Ponds stocked with the upper population fraction of graded prawns showed higher turbidity, total suspended solids and total Kjeldahl nitrogen than the remaining treatments. An increase in the chemical oxygen demand:biochemical oxygen demand ratio from inlet (4.9) to pond (7.1–8.0) waters indicated a non-readily biodegradable fraction enhancement in ponds. The sedimentation mean rate ranged from 0.08 to 0.16 mm day−1 and sediment contained >80% of organic matter. The major factors affecting pond ecosystem dynamic were the organic load (due to primary production and feed addition) and bioturbation caused by stocking larger animals. Data suggest that M. amazonicum grow-out in ponds subjected to a high inflow of nutrient-rich water produce changes in the water properties, huge accumulation of organic sediment at the pond bottom and non-readily biodegradable material in the water column. However, the water quality remains suitable for aquaculture purposes. Therefore, nutrient-rich waters, when available, may represent a source of unpaid nutrients, which may be incorporated into economically valued biomass if managed properly.

Estimation of water fluxes into the Mediterranean Sea

This study provides an estimate of the water runoff into the Mediterranean Sea and its variation from the 1980s to the year 2000. First the variability of climatic and physical factors across the Mediterranean catchment was studied through a principal component analysis. Then a model to estimate the water runoff was developed with the aim to represent this variability, including the various components determining the runoff generation (climatic, physiographic, and pedologic) and overcome the limited data availability for the area. The estimated water fluxes for the 1980–2000 period ranged from 282 to 327 km3 yr−1. Finally, it was shown through a trend analysis, that the fresh water discharge into the Mediterranean Sea did not exhibit any significant change during the study period in spite of a significant increase in temperature and partial decrease of precipitation. Consequently, awareness should be raised on possible depletion of other water stocks in the Mediterranean river basins, such as mountain glaciers and aquifers.

Long-term contracting in hydro-thermal electricity generation: Welfare and environmental impact

We consider electricity generation industries where thermal operators imperfectly compete with hydro operators that manage a (scarce) water stock stored in reservoirs over a natural cycle. We explore how the exercise of intertemporal market power affects social welfare and environmental quality. We show that, as compared to the outcome of spot markets, long-term contracting either exacerbates or alleviates price distortions, depending upon the consumption pattern over the water cycle. Moreover, it induces a second-order environmental effect that, in the presence of a thermal competitive fringe, is critically related to the thermal market shares in the different periods of the cycle. We conclude by providing policy insights.

Macroparasites as biological tags for stock identification of the bluemouth, Helicolenus dactylopterus (Delaroche, 1809) in Portuguese waters

In the present study, the macroparasite assemblage infecting Helicolenus dactylopterus (Delaroche, 1809) in three different areas off the Portuguese coast was evaluated in order to assess their use as biological tags in stock identification. Fish were obtained from commercial landings in Azores, Madeira and mainland Portugal (Peniche), and were examined for macroparasites infections according to standard procedures. Parasite assemblage composition and the prevalence and mean abundance of each macroparasite taxa within each area were calculated. Amongst the 20 taxa found, 13 were selected as good biological tags, presenting statistically different infection levels between areas. Anisakidae larvae, which presented different prevalence and mean abundance levels between the three areas, were further identified according to the restriction fragment length polymorphism (RFLP) pattern on TaqI, HinfI and HhaI. The multivariate discriminant analysis applied to the macroparasites species present in more than one area and showing prevalence higher than 10% revealed a high differentiation among the three sampled areas suggesting at least three different bluemouth stocks in Portuguese waters.

Salmonid‐egg floating boxes as bioindication for riverine water quality and stocking success

The salmonid-egg floating box provides an easy bioindication tool for an assessment of water quality, as demonstrated here for the reintroduction of Europe's largest salmonid species, the huchen Hucho hucho.

Perception of the Arabidopsis Danger Signal Peptide 1 Involves the Pattern Recognition Receptor AtPEPR1 and Its Close Homologue AtPEPR2

Plasma membrane-borne pattern recognition receptors, which recognize microbe-associated molecular patterns and endogenous damage-associated molecular patterns, provide the first line of defense in innate immunity. In plants, leucine-rich repeat receptor kinases fulfill this role, as exemplified by FLS2 and EFR, the receptors for the microbe-associated molecular patterns flagellin and elongation factor Tu. Here we examined the perception of the damage-associated molecular pattern peptide 1 (AtPep1), an endogenous peptide of Arabidopsis identified earlier and shown to be perceived by the leucine-rich repeat protein kinase PEPR1. Using seedling growth inhibition, elicitation of an oxidative burst and induction of ethylene biosynthesis, we show that wild type plants and the pepr1 and pepr2 mutants, affected in PEPR1 and in its homologue PEPR2, are sensitive to AtPep1, but that the double mutant pepr1/pepr2 is completely insensitive. As a central body of our study, we provide electrophysiological evidence that at the level of the plasma membrane, AtPep1 triggers a receptor-dependent transient depolarization through activation of plasma membrane anion channels, and that this effect is absent in the double mutant pepr1/pepr2. The double mutant also fails to respond to AtPep2 and AtPep3, two distant homologues of AtPep1 on the basis of homology screening, implying that the PEPR1 and PEPR2 are responsible for their perception too. Our findings provide a basic framework to study the biological role of AtPep1-related danger signals and their cognate receptors.

Complementary roles of European and national institutions under the Common Fisheries Policy and the Marine Strategy Framework Directive

Abstract Exploited fish and shellfish stocks in European marine waters underlie the Common Fisheries Policy (CFP). The next round of reform of the CFP is due for completion in 2012. The exploitation at maximum sustainable yield (MSY) may be confirmed as the common environmental objective for good environment status (GES) of exploited fish and shellfish stocks of the reformed CFP and the Marine Strategy Framework Directive (MSFD). The foreseen time horizon to achieve or maintain GES by 2020 appears inconsistent with the World Summit on Sustainable Development UN agreement in 2002, which stipulates that maintenance or restoring of stocks to produce MSY be realized by 2015. The MSFD requires instead that by 2015 the national programmes of measures be designed in order to become operational the following year (2016). The MSFD significantly strengthens Member States’ competences and responsibilities to maintain or achieve GES for all exploited fish and shellfish stocks inside territorial waters and the exclusive economic zones (EEZs) with common goals. This will inevitably guide future European Fisheries Council decisions towards long term objectives even at regional levels instead of short term national socio-economic concerns. With such provisions, MSFD is thought to foster and harmonise European fisheries management with ecosystem approaches. For reasons of simplification, the future revision of the CFP should cover all exploited fish and shellfish stocks in all European Seas including territorial zones and EEZs. Member States will need to prepare both for the increased scientific advisory and monitoring efforts expected. The eligibility of additional costs for the Data Collection Framework (DCF) needs to be discussed and decided as soon as these costs are identified and quantified by the competent authorities.

The feeding ecology of little auks raises questions about winter zooplankton stocks in North Atlantic surface waters

Copepods are essential components of marine food webs worldwide. In the North Atlantic, they are thought to perform vertical migration and to remain at depths more than 500 m during winter. We challenge this concept through a study of the winter feeding ecology of little auks (Alle alle), a highly abundant planktivorous seabird from the North Atlantic. By combining stable isotope and behavioural analyses, we strongly suggest that swarms of copepods are still available to their predators in water surface layers (less than 50 m) during winter, even during short daylight periods. Using a new bioenergetic model, we estimate that the huge number (20-40 million birds) of little auks wintering off southwest Greenland consume 3600-7200 tonnes of copepods daily, strongly suggesting substantial zooplankton stocks in surface waters of the North Atlantic in the middle of the boreal winter.

Investment in maturity-at-age and -length in northeast Atlantic cod stocks

The maturation schedule (maturity ogives) for populations differs with geographic location, and cod ( Gadus morhua) stocks are no exception. The environment (latitudinal effects) will have an impact on the maturation schedule, with northern (colder water) stocks growing more slowly and maturing at a greater age. This is, however, modified by the impacts of fishing, whereby under severe exploitation, maturation tends towards an earlier age. Cod in the Irish Sea are towards the southern end of the species’ range and the stock is severely depleted, with most males and females maturing between 2 and 3 years of age and at a relatively small size. The North Sea cod stock is considered to be harvested unsustainably, and, in addition, in recent years has shown the classic shift in maturity schedule to most fish maturing at a younger age and smaller size. The Barents Sea (Northeast Arctic) cod stock has undergone major changes in population size, but is currently not overexploited. There have also been shifts in the maturation schedules of Northeast Arctic cod. However, over the past decade or so, there has not been a clear trend in the age- or length-at-50% maturity with time or population size. The relationship between the age- and length-at-50% maturity differs markedly between the three cod stocks (Irish, North and Barents Seas), when considered over years and by year classes, which suggests that there may be stock- or area-specific characteristics. Such stock-specific differences will have consequences for applying relationships between areas where the maturity schedules are dynamic, e.g. through climate change or under severe or changing exploitation patterns.

Evaluation of soil water storage efficiency for rainfall harvesting on hillslope micro-basins built using time domain reflectometry measurements

Micro-basins are slope management structures built out of earth and stones on hillslopes around cultivated trees (e.g., olive trees) for the harvesting of rainfall and runoff water, and for the rehabilitation of land degraded by water erosion. In this study, the results of an experimental survey for the comparison of soil water content for both inside and outside the micro-basins are analyzed. Measurements are taken after some rainfall events from January to December 2003 in a hilly region of Central Tunisia. The time domain reflectometry technique is used to measure soil moisture in 15 sets of soil profiles (inside and outside) at three different depths. Four different soils are evaluated, i.e., Cambisols, Kastanozems, Arenosols, and Calcisols. The data analysis shows a significant improvement on the water stock obtained by this type of management. The differences in water storage with respect to soil type, depths, and tillage are evident, but strongly connected to farm management. For optimal management conditions an important increase of average water stock is observed; however, for bad or no farm management the amelioration is zero or is even deteriorating the state of vegetation.

Evaluation on different forms of Moringa oleifera seeds dosing on sewage sludge conditioning

The effect of different form of dosing using Moringa oleifera seeds in sewage sludge conditioning was studied. Settled activated sludge after clarification process was obtained from sludge holding tank in Sewage Treatment Plant, Taman Tun Dr. Ismail, Kuala Lumpur, Malaysia. In this study, sludge conditioning with Moringa oleifera seeds in 3 different forms: dry powder, distilled water extracted and salt extracted (1 N NaCl) — were studied in comparison with chemical polymer, Zetag 7653. The study applied operator's specification, Indah Water Konsortium Sdn. Bhd., Malaysia (IWK) with preparation of Moringa oleifera in water and salt stock solution and Zetag 7653 stock solution were done at 650 rpm for 1 h. Sludge conditioning was then operated at 60 rpm for 45 min using jar test apparatus. Using specific resistance to filtration (SRF) as a parameter, Moringa oleifera in dry powder form at dosage of 2000 mg/L was comparable to 50 mg/L Zetag 7653 in reducing the value from 8.0×1010 to 3.3×1010 m/kg (2.5 times of magnitude). Therefore, Moringa oleifera in dry powder form was as effective as Zetag 7653. There was no significant change in CST between the three methods of extraction for Moringa oleifera. Without applying filtration using muslin cloth, sludge solid content when dosed with Moringa oleifera in distilled water extracted form showed the least increment at 17.08%.

Analysis of hydraulic conditions and HRT on the basis of experiments and simulations on soil column

The hydraulic residence time (HRT) is a key parameter affecting the soil aquifer treatment process (SAT) efficiency as tertiary treatment of wastewater through infiltration in vadose zone. In order to maximize the HRT, a pulsed feeding technique of a salt solution (used as conservative tracer) was adopted to allow the increase of HRT and soil aeration between pulses. For this reason, several laboratory column experiments combined with the use of a numerical model was conducted. The optimal number of pulsations that meet with the maximum of the HRT and the temporal variation of the water saturation into the column was determined for different applied hydraulic heads. It varies between 10 and 12. The maximum corresponding water stock in the porous media column was evaluated to about 84%, 79% and 73%, respectively, for an applied hydraulic head of 96, 75 and 50 cm. The applied hydraulic head had an important effect on the HRT. In fact, this parameter varies from almost 6.5 to 10.8 h for an applied hydraulic head of 96 and 50 cm. The change in the permeability of the soil had also a significant effect on the HRT. Hence, HRT is decreased of about 9% when the soil permeability at saturation is multiplied by 2, and increases of about 11% when the permeability is two times lower.

Satellite data show Indian water stocks shrinking

Groundwater depletion raises spectre of shortages.

Unpredictable and significant variability of rainfall: carryover stocks of water and food necessary

Unpredictable and significant variability of rainfall: carryover stocks of water and food necessary

Whole Ecosystem Evidence of Eutrophication Enhancement by Wetland Dredging in a Shallow Tropical Lake

The purpose of this research was to assess the effects of dredging performed in a marginal wetland colonized by aquatic macrophytes on eutrophication of the adjacent shallow tropical lake (Imboassica Lake, Brazil). The river mouth of the Imboassica River that drains into Imboassica Lake had been densely colonized by aquatic vegetation dominated by Typha domingensis (Pers.) when it was dredged. Total and dissolved nitrogen and phosphorus concentrations were measured monthly over 13 years at four stations in the Imboassica river-lake system. Dredging activities reduced phosphorus and nitrogen retention at the river mouth and subsequently increased these nutrient stocks in the lake waters. Nutrient retention by non-dredged wetland was estimated to be ca. 1,200 kg year−1 (87.3 g m−2 year−1) for nitrogen and 60 kg year−1 (4.5 g m−2 year−1) for phosphorus. Our whole-lake approach suggested that dredging might intensify rather than mitigate eutrophication in shallow tropical lakes when the removal of aquatic macrophytes is coupled to the persistence of anthropogenic nutrient inputs from the watershed.

Internalization of Salmonella enterica serovar Montevideo into greenhouse tomato plants through contaminated irrigation water or seed stock.

Tomatoes have been linked to outbreaks of salmonellosis, demonstrating the need to identify sources of contamination. Objectives of this study included determining the ability for Salmonella enterica serovar Montevideo to be internalized into tomatoes from contaminated irrigation water and seed stock, and establishing whether Salmonella Montevideo can survive in fertilizer solutions. Six treatment groups (five plants per group) were irrigated with 350 ml of 7 log CFU/ml of Salmonella Montevideo every 14 days for 70 days, each group receiving an increased number of contaminated water events progressively: group 1 received one contaminated watering at day 0, and group 6 received a total of six contaminated waterings. Group 7 was a control, and group 8 was grown from seeds soaked in 8 log CFU/ml of Salmonella Montevideo for 24 h. All plants were watered daily with uncontaminated water. Three replications were completed. Fruit from every plant, and roots, stems, and leaves of one plant per treatment were sampled. All tomatoes were negative for Salmonella Montevideo; five root samples tested positive. For fertilizer studies, a commercially available fertilizer, two custom mixed and 1.0% dilutions of each (total of six solutions), and sterile water were inoculated with 8 log CFU/ml of Salmonella Montevideo and stored at 25 degrees C. Solutions were sampled at 24, 48, and 72 h. There were no differences (P > or = 0.05) between survival of Salmonella Montevideo in diluted fertilizers and the control. Results indicate Salmonella Montevideo is unable to contaminate tomato fruit via irrigation water and seed stock but can survive in fertilizer solutions.

Growing Rice Under Managed Water Table System:

A lot of water is used in rice cultivation but under dwindling global water stocks, this issue of water use must be examined. Therefore rice (Oryza sativa L.) cultivar IR36 was grown in a controlled sand medium under nitrogen limiting conditions using a water table management system. The treatments used were water table at depths of 27.5cm, 15cm below the surface and saturated sand with the water table at the soil surface. Fifty four rice plants were grown for a period of 68 days. There were five harvests, with 9 plants harvested at each of the first four and 18 plants at the last harvest. Plant growth was determined by measuring rooting depth when harvesting, and the rest, shoot length, root dry mass and shoot dry mass after harvest. The saturated treatment was highest for all parameters measured followed by the 15cm and finally the 27.5cm treatment. The water release characteristics indicated that there were no major differences between moisture contents when the water table was held at the depths used. For most of the parameters measured, significant differences emerged only after about 25 days after seeding indicating that there was the possibility of some water saving in the early days of rice production. Contrary to other findings, the rooting depth for the saturated treatment was higher than those for the 15cm and 27.5cm treatments, a factor, which could be attributed to the fact that rooting depth is greater when nitrogen is limiting. Journal of the Ghana Science Association Vol. 10 (2) 2008: pp. 39-50

A framework for assessing the trade‐offs between economic and environmental uses of water in a river basin

AbstractSignificant increases in water diversion for irrigation and other uses have taken place worldwide throughout the twentieth century, often with negative consequences for environmental sustainability.In this paper a framework which can be used to undertake an assessment of this trade‐off problem is presented. The framework aims to achieve a balance between water extractions for irrigation and other uses and environmental demand. It involves, among many factors, an understanding of the hydrological, environmental, economic and social consequences of diverting water.The research component of the framework comprises three key elements: water cycle analysis, economic analysis and social analysis. At the core of the water cycle analysis is the characterisation of the water stocks and flows in the systems and a modelling framework to analyse system responses to water‐sharing policies and trade‐offs between extractive and environmental uses. The economic analysis focuses on the valuation of water allocated to each use including the environment, whilst the social analysis is centred on the relative values used to balance water extractions for society's needs and the environment. This framework is illustrated with examples from the Krishna Basin in India and the Murray– Darling Basin in Australia. Copyright © 2009 John Wiley & Sons, Ltd.