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Cabled ocean observatory data reveal food supply mechanisms to a cold-water coral reef Full text
2019
Van Engeland, Tom | Godø, Olav Rune | Johnsen, Espen | Duineveld, Gerard C.A. | van Oevelen, Dick
We investigated food supply mechanisms to a cold-water coral (CWC) reef at 260 m depth on the Norwegian continental shelf using data from a cabled ocean observatory equipped with Acoustic Doppler Current Profilers (ADCPs), an echosounder, and sensors for chlorophyll, turbidity and hydrography in the benthic boundary layer (BBL). Tidal currents of up to tens of cm s−1 dominated BBL hydrodynamics while residual currents were weak (∼10 cm s−1), emphasizing a supply and high retention of locally produced phytodetritus within the trough. A direct connection between the reefs and surface organic matter (OM) was established by turbulent mixing and passive particle settling, but relative contributions varied seasonally. Fresh OM from a spring-bloom was quickly mixed into the BBL, but temperature stratification in summer reduced the surface-to-bottom connectivity and reduced the phytodetritus supply. A qualitative comparison among acoustic backscatter in the ADCPs (600 kHz, 190 kHz) and echosounder (70 kHz) suggests that vertically migrating zooplankton may present an alternative food source in summer. Nocturnal feeding by zooplankton in the upper water column sustains downward OM transport independent from water column mixing and may dominate as food supply pathway over sedimentation of the phytodetritus, especially during stratified conditions. In addition, it could present a concentrating mechanism for nutritional components as compensation for the deteriorating phytodetritus quality. Overall, the observed patterns suggest seasonal changes in the food supply pathways to the reef communities. The moderating role of temperature stratification in phytodetritus transport suggests stronger dependence of the cold-water corals on zooplankton for their dietary requirements with increased stratification under future climate scenarios. This study demonstrates the added value of permanent ocean observatories to research based on dedicated campaigns and regular monitoring.
Show more [+] Less [-]Trade-offs and synergies in the water-energy-food nexus: The case of Saskatchewan, Canada Full text
2021
Wu, Linuo | Elshorbagy, Amin | Pande, Saket | Zhuo, La
Socioeconomic and climatic changes and limited water resources pose various challenges to water, energy, and food sectors across the globe. The inevitable interactions between water, energy, and food systems bring about trade-offs but also synergies under different decisions and policies. To gain insights into these issues, we developed a water-energy-food (WEF) nexus model that incorporates both production (supply) and demands sides of WEF systems into a single system-of-systems model using the system dynamics (SD) approach. The model is applied to Saskatchewan, Canada, and so is named WEF-Sask. The model results reveal the various levels of sensitivities of water, energy, and food (and feed) sectors to the socioeconomic and climatic drivers. The analysis of trade-offs and synergies shows that the proposed large irrigation expansion (400%) boosts food production by 1.6% while reducing hydropower production by 2.7% in Saskatchewan. Wind energy expansion strategy (from 5% to 30% of total capacity) makes synergies that not only contribute to electricity supply but also reduce greenhouse gas emissions, industrial water demand, and groundwater use by 2.0, 5.7, and 3.8%, respectively. Biofuel use (blending mandate: 10% ethanol and 5% biodiesel) in transportation cuts GHG emissions by 1.2% but reduces the potential food export (food surplus) by 5.0%. The WEF-Sask model allows for scenario analysis toward integrated resources management, and its generic model structure can be expanded to other regions.
Show more [+] Less [-]Agricultural production, water use and food availability in Pakistan: Historical trends, and projections to 2050 Full text
2017
Kirby, Mac | Ahmad, Mobin-ud-Din | Mainuddin, Mohammed | Khaliq, Tasneem | Cheema, M.J.M.
Forty seven percent of the population of Pakistan is food insecure, access to food is uneven and malnutrition is widespread. In addition, food production depends greatly on irrigation, including the use of substantial volumes of water from already stressed aquifers. Our aim in this paper is to examine the implications of continued population growth on the required production of food and the implied water demand.We examine the historical trends of crop production, water use, food availability and population growth in Pakistan, and project them forward to 2050. Food availability has improved over recent decades, mostly as a result of increasing the area and water use of crops and fodder, and partly as a result of importing more pulses and cooking oils. We show that a continuation of current trends leads to nearly a doubling of the (already unsustainable) groundwater use. There is uncertainty in the magnitude of climate change impacts, but climate change may further exacerbate matters. To avoid further increases of groundwater use, some combination would be required of: more dams and other irrigation infrastructure; increasing crop yields (particularly yields per unit volume of water) at a greater rate than in the past; a change in crop mix away from high water use crops like rice and sugarcane, to crops that use less water; and, exporting less and importing more food. The alternatives appear difficult to implement quickly, so it appears likely that in the short to medium term more groundwater will be consumed, with attendant problems of water quality and sustainability. Our analysis provides new perspectives on past trends and future food and water (including groundwater) challenges.
Show more [+] Less [-]Dry mixing of food powders: Effect of water content and composition on mixture quality of binary mixtures Full text
2015
Shenoy, Pooja | Xanthakis, Epameinondas | Innings, Fredrik | Jonsson, Caroline | Fitzpatrick, John | Ahrné, Lilia
This work studied the effect of composition of powders and water content on mixture quality (MQ) of three binary powder mixtures with good (salt/paprika or salt/sugar) or poor mixing (salt/oregano) behaviour. The mixing behaviour was assessed using coefficient of variation. Results showed that mixture composition did not influence the MQ of sugar/salt and paprika/salt within 20–80% salt content range but it did influence the MQ of oregano/salt with a progressive dis-improvement in MQ with higher oregano content and also for low concentrations of 1% salt. Water content did have an effect on mixing behaviour. When paprika with high water activity (aw) was mixed with salt, the time required to reach good MQ was longer because of the increased cohesiveness and when oregano with high aw was mixed with salt it displayed improved MQ because salt particles were able to stick onto the larger oregano particles and reduced segregation.
Show more [+] Less [-]The bactericidal effect of electrolyzed water on fresh food as influenced by rinsing methods and treatment times
2008
Kamitani, Y.(Kagoshima Univ. (Japan). Faculty of Agriculture) | Hiejima, H. | Morita, K. | Yagi, F.
Strong acidic electrolyzed water (SAcEW) is generated by using a diaphragm type electrolytic cell and adding a small amount of salt solution to the tap water. The acidity of this water causes chloride ions, as the major factor in sterilization process, to form hypochlorous acid. Therefore, it is said that the sterilization time with SAcEW is shorter than with sodium hypochlorite generally used for food sterilization. After being registered as a food additive (2002) in Japan, SAcEW began to be used for washing food in food processing facilities in order to improve the food sterilization level. In this research, the possibility of an enhanced sterilization effect of SAcEW generated by a water electrolyzer was evaluated by adding physical washing methods (ultrasonic, stream overflow, bubbling) and pre-washing with strong alkaline electrolyzed water (SAlEW) which is generated at the same time. As a result, the combination with pre-washing with SAlEW was found to be less effective than washing with SAcEW only when comparing the same washing time. As for the supplementation of physical washing methods, the stream type was found most effective. In addition, comparison between the sodium hypochlorite treatments (200 mg/L, soaked for 5 minutes) recommended by the Japanese Ministry of Health, Labor and Welfare for raw food materials and the SAcEW treatment for 10-30 seconds suggested equivalent sterilization effects on raw food materials.
Show more [+] Less [-]Comparative evaluation of anaerobic co-digestion of water hyacinth and cooked food waste with and without pretreatment Full text
2018
Barua, Visva Bharati | Rathore, Vidhi | Kalamdhad, Ajay S.
The present study is a comparative evaluation of anaerobic co-digestion of water hyacinth and food waste with and without pretreatment. The novelty of this anaerobic co-digestion study is that it highlights the effect of pretreatment and mixing ratio. Two set up of bio-chemical methane potential (BMP) experiments for the same mixing ratios but with or without pretreatment were simultaneously conducted. In set I, untreated water hyacinth and food waste was co-digested whereas in set II, pretreated water hyacinth and food waste was co-digested. Higher biogas production in set I and II was witnessed by the mixing ratios 2 and 1.5 respectively indicating them to be the ideal mixing ratio. Considerably higher biogas production was observed for both the setup of anaerobic co-digestion than mono-digestion. Also, set II exhibited higher biogas production than set I. The results portrayed that pretreatment followed by co-digestion provided quicker and higher biogas production.
Show more [+] Less [-]Preparation and optimization of submicron chitosan capsules by water-based electrospraying for food and bioactive packaging applications Full text
2017
Sreekumar, Sruthi | Lemke, Philipp | Moerschbacher, Bruno M | Torres-Giner, Sergio | Lagaron, Jose M
In the present study, a well-defined set of chitosans, with different degrees of acetylation (DA) and degrees of polymerization (DP), were processed by solution electrospraying from a water-based solvent. The solution properties, in terms of surface tension, conductivity, viscosity, and pH, were characterized and related to the physico-chemical properties of the chitosans. It was observed that both DA and DP values of a given chitosan, in combination with biopolymer concentration, mainly determined solution viscosity. This was, in turn, the major driving factor that defined the electrosprayability of chitosan. In addition, the physico-chemical properties of chitosans highly influenced solution conductivity and results indicated that the chitosan solutions with low or low-to-medium values of conductivity were the most optimal for electrospraying. The results obtained here also demonstrate that a good process control can be achieved by adjusting the working conditions, i.e . applied voltage, flow-rate, and tip-to-collector distance. Finally, it was also shown that electrosprayability of chitosan with inadequate physico-chemical properties can be improved by solution mixing of very different kinds of this polysaccharide. The resultant electrosprayed submicron chitosan capsules can be applied for encapsulation of food additives and to develop bioactive coatings of interest in food packaging, where these particles alone or containing functional ingredients can be released from the package into the food to promote a health benefit.
Show more [+] Less [-]Balance de calor e interacción agua-nutrientes-cadena alimenticia en el lago de Zapotlán, México Full text
2007
Ortiz-Jiménez, Mario A. | Anda, José de
Resumen Se presenta un balance de calor del Lago de Zapotlán que fue resuelto numéricamente mediante el método de Runge-Kutta de cuarto orden con un incremento de tiempo de un día. A semejanza de otros lagos tropicales, el presupuesto anual de calor es muy bajo. La temperatura del lago (correlacionada con la radiación atmosférica y la radiación de fondo), la acción del viento (correlacionada con la radiación solar), y los escurrimientos (correlacionados con la radiación atmosférica, la radiación de fondo, la precipitación sobre el lago y la temperatura del lago), producen el mezclado del lago durante las estaciones de invierno, primavera y verano. Pero en el inicio del otoño, al disminuir el flujo neto de calor superficial y terminar las lluvias, el hipolimnión se enfría levemente debido a que esta capa es ocupada por escurrimientos más fríos y más densos. Esta pequeña diferencia térmica provoca que la columna de agua se estratifique de manera inestable. Los episodios alternados de mezclado y estratificado afectan significativamente el ciclo de nutrientes y la dinámica de la cadena alimenticia del lago. | Abstract This paper presents a heat balance for Lake Zapotlán, which was solved numerically using the fourth-order Runge-Kutta method with a step size of one day. Like other tropical lakes, the annual heat budget of Lake Zapotlán is very low. Lake temperature (correlated with both atmospheric longwave radiation and water back radiation), wind strength (correlated with solar shortwave radiation, and runoffs (correlated with atmospheric longwave radiation, water back radiation, precipitation on lake and lake temperature) produce lake mixing during three seasons: winter, spring and summer. When fall begins, as the net surface heat flux diminishes and rainfall ends, the epilimnion is slightly cooled since this layer receives colder, denser runoff. This small difference in temperature causes the water column to stratify in an unstable manner. The alternating episodes of mixing and stratification significantly affect the nutrient cycle and the dynamics of the food chain.
Show more [+] Less [-]Green and innovative technique develop for the determination of vanadium in different types of water and food samples by eutectic solvent extraction method Full text
2020
Ali, Jamshed | Tuzen, Mustafa | Kazi, Tasneem G.
A green and innovative eutectic solvent based extraction method was proposed for the determination of trace level vanadium in water and food samples by graphite furnace atomic absorption spectrometry. In this extraction technique magnetic stirrer was used for preparation of eutectic solvent by mixing of zinc chloride and acetamide at different molar ratios. Extraction capability of eutectic solvent was increased by adding a non ionic surfactant (Triton X-114) to enhanced phase transfer ratio, to significantly increase the recovery of hydrophobic complex of vanadium with ammonium pyrrolidine dithiocarbamate. A multivariate technique was applied to evaluate the important extraction parameters, which plays important role for optimum recovery of the targeted analyte by proposed extraction method. Multivariate techniques such as (factorial design and central composite design) were applied to screening out the most significant extraction parameters and optimized them. Under optimized extraction conditions, limit of detection and enhancement factor were found to be 0.01 µg L⁻¹ and 64.6, respectively. The relative standard deviation for the determination of trace level vanadium at 0.32 µg L⁻¹ concentration, was achieved to be <3.0% (n = 10). Validity and accuracy of the proposed extraction method was checked by analysis of certified reference materials of Canadian lake water and tomato leaves with % age recovery >98%. The eutectic solvent extraction method was successfully applied for the determination of the trace level vanadium in real water samples of different sources and acid digested food samples, collected from different locations of Tokat city, Turkey.
Show more [+] Less [-]A newly synthesized graft copolymer for magnetic solid phase microextraction of total selenium and its electrothermal atomic absorption spectrometric determination in food and water samples Full text
2019
Acikkapi, Ayse Nihan | Tuzen, Mustafa | Hazer, Baki
A newly synthesized polystyrene-g-polyoleic acid-g-polyethylene glycol graft copolymer (PoleS-PEG) was used as adsorbent in the solid phase microextraction of selenium ions by using electrothermal atomic absorption spectrometry (ETAAS). Neodymium magnet was used for separation of analyte ions. Various analytical parameters such as pH, adsorbent amount, mixing time, eluent solution, sample volume, etc. were optimized. The matrix effects of some cations and anions were also studied. The capacity of the adsorbent was found 11.5 mg g−1. The preconcentration factor was found to be 50. The detection limit (LOD) and quantification limit (LOQ) were found 6.06 ng L−1 and 20 ng L−1, respectively. The calibration curve was linear in the range of 0.02–4.0 μg L−1. Relative standard deviation was found 3.2%. The accuracy of the method was provided by using standard reference materials. The optimized method was successfully applied to natural water and food samples.
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