High Amounts Of Nutrients Research Articles

Balancing of Ocean Acidification by Superoxide Redox Chemistry?

O acidification is typically caused by production of carbonic acid (H2CO3) through the dissolution of increasing atmospheric CO2, which adds to CO2 plus DIC (dissolved CO2, H2CO3, HCO3 −, and CO3 2−) produced in seawater by several processes including biological ones (primary production followed by respiration). Acidification can decrease the saturation states of carbonate minerals, which may considerably endanger the dynamics, structure and biodiversity of coral reefs and other marine calcifying organisms. The consequence is the decline in the early development stages of shellfish, coral reefs, or other marine calcifiers, with impacts on fertilization, sexual reproduction, cleavage, larval settlement, survival and growth, finally causing a substantial population decline. Decline in shellfish or coral reefs, which form the foundation of marine ecosystems, would markedly affect the whole food webs and marine population dynamics. Despite the apparent straightforwardness of such a scenario, the actual determination of the impact of atmospheric CO2 on seawater pH is a difficult task. This happens primarily because of the relatively small pH changes, unless very long time spans are taken into account. Moreover, pH modifications can also take place at a local scale because of several possible confounding factors, of which we will show the potential role of superoxide chemistry. Among additional causes for seawater pH variation, one is the acidification connected with eutrophication phenomena that have increased worldwide since the last few decades. Indeed, changes in land-use practices can induce the release of high amounts of nutrients and terrestrial organic matter (OM) to coastal seawaters, including dissolved OM (DOM) and particulate OM (POM). The transformation of organic P and N into phosphate and nitrate because of microbial or photochemical processes can cause a significant decrease of the alkalinity of coastal seawater and, therefore, a decrease in pH. Another possibility (although limited in space and time) is the elevated production of CO2 and DIC during harmful algal blooms, which can significantly alter the pH of seawater as long as they are operational. Eutrophication phenomena and algal blooms can both be enhanced by global warming, which causes an increase of surface seawater temperature and leads to a longer summer stratification period. In warm, sunlit surface seawater the photochemical and biological processes that are involved in the degradation of DOM and POM can be strongly enhanced, leading to increased production of CO2 and of anionic species that decrease the alkalinity of seawater. The third possible issue is connected with atmospheric acid rain, most notably involving HNO3 and H2SO4 that can directly lower the seawater pH. All such processes are usually limited to the coastal areas that are most affected by eutrophication phenomena, while acid rains are not expected to have a comparatively important impact on the pH of the open ocean. Within this context, an additional factor of potential importance is represented by the chemistry of superoxide. The radical ion O2 −• is produced by various sources including extracellular generation by heterotrophic bacteria that are commonly detected in lakes, soil, hydrothermal vents, marine sediments, estuaries, and oceans. Rates of superoxide production normalized to the proportion of metabolically active cells are found to vary between 0.02 ± 0.02 amol cell−1 hour−1 (mean ± standard error) and 19.4 ± 5.2 amol cell−1 hour−1. Such production rates could lead to an alteration of seawater pH because of H consumption upon dismutation of superoxide (2 O2 −• + 2H → H2O2 + O2). The latter process is catalyzed by redox-active metals such as Cu(I/II) and Fe(II/ III) and possibly (but still controversially) by organic compounds with redox-capable moieties. With a biological generation rate of O2 −• prudentially assumed to be 0.2 pmol dm−3 s−1, which is only 10% of that reported by Diaz et al., based on superoxide dismutation alone one can have a H consumption rate of ∼6 μmol dm−3 year−1. A simplified seawater model shows that the process would be able to compensate for an acidification rate of 0.1−0.3 pH units year−1 Viewpoint

Antimutagenicity and anticlastogenicity of glutinous purple rice hull using in vitro and in vivo testing systems

Glutinous purple rice (Oryza sativa L.var. indica) contains high amounts of nutrients and phytochemicals. Rice hull is a low-value waste product, yet contains many bioactive ingredients. The genotoxicity and antigenotoxicity of the dicholoromethane extract of glutinous purple rice hull were investigated. The amounts of phenolic compounds, flavonoids and γ-oryzanol of hull extract were 174.0±55.0, 220.0± 7.5, and 23.6±0.1 mg/g extract, respectively. Lower amounts of tocopherols and tocotrienols were detected. The mutagenicity and antimutagenicity of the extract were determined using a Salmonella mutation assay. Rice hull extract was not mutagenic in either strain TA98 or TA100 in the presence and absence metabolic activation. The extract showed antimutagenicity against AFB1 and MeIQ, but did not against AF-2 and NaN3. It enhanced the mutagenic activity of benzo(a)pyrene in TA100 with metabolic activation. The toxicity and genotoxicity of dichloromethane extract of glutinous purple rice hull were further studied in an animal model. The extract was non-toxic to rats at a single dose of 2000 mg/kg bw of extract following the OECD Guideline 425 protocol. The clastogenicity and anticlastogenicity of the extract were studied using a rat liver micronucleus assay. The oral administration of 500 mg/kg bw of glutinous purple rice hull extract for 28 days did not affect the number of micronucleated hepatocytes or mitotic index in rats, but it significantly decreased the number of micronucleated hepatocytes in diethylnitrosamine-initiated rats. Furthermore, the dichloromethane rice hull extract significantly enhanced glutathione-S-transferase activity in the livers of diethylnitrosamine-initiated rats. In conclusion, dichloromethane extract of glutinous purple rice hull presented antimutagenic and anticlastogenic potential. The inhibitory mechanism of this rice hull extract might be partly due to either induction of detoxifying enzymes or inhibition of metabolizing enzymes.

Biotests for environmental quality assessment of composted sewage sludge

The quality of sewage sludge-based products, such as composts and growth media, is affected by the contamination of sewage sludge with, potentially, hundreds of different substances. Therefore, it is difficult to achieve the reliable environmental quality assessment of sewage sludge-based products solely based on chemical analysis. In the present work, we demonstrate the use of the kinetic luminescent bacteria test (ISO 21338) to evaluate acute toxicity and the Vitotox™ test to monitor genotoxicity of sewage sludge and composted sewages sludge. In addition, endocrine-disrupting and dioxin-like activity was studied using yeast-cell-based assays. The relative contribution of industrial waste water treated at the Waste Water Treatment Plants led to elevated concentrations of polyaromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and polychlorinated dibenzo-p-dioxins and -furans (PCDD/F) in sewage sludge. The effect of elevated amounts of organic contaminants could also be identified with biotests able to demonstrate higher acute toxicity, genotoxicity, and potential for endocrine-disruptive properties. Additional extraction steps in kinetic luminescent bacteria test with DMSO and hexane increased the level of toxicity detected. Composting in a pilot-scale efficiently reduced the amounts of linear alkylbenzensulphonates (LASs), nonylphenols and nonylphenolethoxylates (NPE/NPs) and PAH with relative removal efficiencies of 84%, 61% and 56%. In addition, decrease in acute toxicity, genotoxicity and endocrorine-disrupting and dioxin-like activity during composting could be detected. However, the biotests did have limitations in accessing the ecotoxicity of test media rich with organic matter, such as sewage sludge and compost, and effects of sample characteristics on biotest organisms must be acknowledged. The compost matrix itself, however, which contained a high amount of nutrients, bark, and peat, reduced the sensitivity of the genotoxicity tests and yeast bioreporter assays.

Picoplankton seasonal variation and community structure in the northeast Adriatic coastal zone

The bacterial community in coastal waters of northeastern Adriatic Sea was dominated by SAR11 and Sulfitobacter taxa throughout the year. The seasonal distribution of bacterioplankton taxa showed continual differences between surface (0m) and bottom (27m) layers. The surface assemblage was represented by Actinobacteria, Cyanobacteria, Alphaproteobacteria, and Gammaproteobacteria, while the bottom assemblage was made up of Bacteroidetes, Cyanobacteria and Alphaproteobacteria. As SAR11 was more dominant in the bottom layer, its appearance may be linked to northward transport of oligotrophic waters of higher salinity from the south. Gammaproteobacteria appeared only in the surface layer during summer, influenced by higher amounts of nutrients, brought in by the Po River. Synechococcus was the most abundant taxon at the genus level. Dominance of Synechococcus during the whole season agrees with its dominance in terms of abundance determined by flow cytometry, and confirms its utmost importance in the picoplankton community of this area. We found two different types of Synechococcus: one type with high similarity to Synechococcus CC9902, present in the surface and bottom layers, and another one similar to Synechococcus WH7803, present only in the surface layer. Oligotrophic conditions together with complex hydrological features of this area were reflected in diversification and dynamic shifts of surface and bottom assemblages.

Aboveground biomass and nutrients in an 18-years-old stand of blue spruce (Picea pungens Engelm.) as a substitute tree species

Sample trees were taken for analyses from an 18-years-old blue spruce stand growing in the summit part of the Jizerské hory Mts. (Czech Republic). The sample trees were measured and dry matter and nutrient contents were analysed in needles, branches, bark and stem wood. Based on the actual stand structure, correlations were calculated between the diameter, dry weight of components and nutrient reserves. Dry matter of the stand constituted 46% of the stand fresh weight. The highest amount of nutrients was accumulated in needles (from 42% in magnesium to 82% in phosphorus) and the lowest in the stem wood (from 2% in phosphorus to 15% in potassium). Regarding the character of the locality, the complete removal of aboveground biomass during tending operations represents a considerable loss of nutrients. If only the merchantable timber volume is processed, the loss of the elements from the ecosystem could be reduced to 8% (phosphorus) to 22% (calcium and potassium) of the total content of these elements in the aboveground biomass of removals.  

Dynamics of fine root N, P and K in high elevation forests of central Himalaya

Fine root nutrient dynamics were calculated for one year in three high elevation forests of Indian central Himalaya. In all sites, fine root nutrient concentrations varied with respect to forests and seasons. N concentration in fine roots was highest followed by K and P. In general, fine roots showed their highest nutrient concentrations during the rainy season and lowest in winter. Higher nutrient concentrations during the rainy season may be related to favorable moisture and temperature regimes which in turn results in increased plant growth activities. Present fine root nutrient amounts and nutrient uptake values decreased towards high elevations. In general, the highest amounts of nutrients in both live and dead fine roots were observed in September and the lowest in the month of June. Turnover rates of the nutrients in the fine roots also decreased with an increase in elevation.

Phytoplankton and Zooplankton Modeling of Pishin Reservoir by Means of an Advection-Diffusion Drought Model

Phytoplankton and zooplankton concentrations in Pishin reservoir are predicted employing a three-dimensional numerical model in this paper. Modeling is performed using a numerical model based on mass transport equation. Advection, diffusion and source/sink processes are considered as separate subroutines for predicting the concentrations of phytoplankton and zooplankton in the reservoir. Finite volume method is used for solving the governing equations of water quality and water flow. The model is adopted for drought periods and dry climates. Water flow in the reservoir is simulated by Fluent software that is a finite volume numerical model. The model also uses a sub-model for compatibility providing of geometry between software and water quality model. A one-year period of experimental works and sampling is done in the study area. Phytoplankton and zooplankton cycles are used to determine the sources and sinks. Standard methods are chosen for experimentation. The concentrations of phytoplankton and zooplankton are calculated and measured in a one-year period. The concentrations of phytoplankton and zooplankton decrease in the depth of water and the decease rate is not linear. Also the concentrations are increase in the times after the maximum floods because of the inflows contain high amounts of nutrients. The calculated values by the model are in good agreement with measured values of laboratory works. It was concluded that the model can be used for water quality prediction in such aquatic environments.

The effect of flooding on carbon and nutrient standing stocks of helophyte biomass in rewetted fens

Rewetting can strongly affect the matter balance of peatlands. Owing to evidence of increasing CH4 emissions and P mobilisation after rewetting, the effects of peatland restoration on climate, eutrophication risks and related controversies are discussed. Our study focuses on the role of helophytes in the carbon and nutrient balance of rewetted fen grasslands of NE Germany. We hypothesise that the helophytes Carex riparia, Glyceria maxima, Phalaris arundinacea, Phragmites australis and Typha latifolia differ in biomass production and nutrient standing stock according to site conditions and harvest time. We analysed the helophyte biomass three times a year and continuously measured water levels and quality. Biomass production, nutrient standing stock and litter accumulation were highly species specific and depended on nutrient availability, mean water levels and harvesting time. We conclude that helophytes store considerable amounts of carbon and temporarily improve the water quality by withdrawing high amounts of nutrients from the top soil during the growing season, and by reducing nutrient discharges. Restoring peatlands as effective nutrient and carbon sinks in the landscape should favour highly productive potentially peat-forming helophytes as Phragmites australis by establishing adequate water levels. If nutrients are to be removed from the degraded peatland, then management can combine the restoration of helophyte stands by rewetting with harvesting measures.

NUTRIENT BIOAVAILABILITY IN SALT AFFECTED SOILS

Salt affected soils limit crop yields around the world. Knowledge of how nutrient availability is affected in plants growing on salt affected soils is important in adopting appropriate management practices to satisfy plants’ nutritional requirements and improve yields to meet food demands of increasing world populations. In the salt affected environment plants required to absorb essential nutrients from a dilute source in the presence of highly concentrated nonessential nutrients. Nutrient uptake and use efficiency in salt affected soils is low due to salt stress and negative interactions with cations and anions present in high concentrations. Hence, a higher amount of nutrients is necessary in salt affected soils compared to normal soils. Biological nitrogen fixation is also adversely affected in legumes grown on salt affected soils. Salts also reduce activity of many enzymes which supply energy for nutrient uptake. The important soils and plant management practices which can improve nutrient uptake and use efficiency in salt affected soils are use of soil amendments to reduce effect of salts, application of farmyard manures to create favorable plant growth environments, leaching salts from soil profile and planting salt tolerant crop species or genotypes within species. Addition of fertilizers, especially potassium may also help in reducing salinity effects and improving nutrient use efficiency.

Influences of water column nutrient loading on growth characteristics of the invasive aquatic macrophyte Myriophyllum aquaticum (Vell.) Verdc.

Nuisance growth of Myriophyllum aquat- icum has often been attributed to high amounts of nutrients. The uptake of nitrogen and phosphorus from sediments and their allocation have been documented in both natural and laboratory popula- tions. However, nutrient loading to surface water is increasingly becoming an important issue for water quality standards. Aquatic macrophytes that develop adventitious roots may be able to survive through the uptake of water column nutrients. Our objectives for this study were to assess M. aquaticum growth when combinations of nitrogen and phosphorus were added to the water column. Mesocosm experiments were conducted where nitrogen (1.8, 0.8, and 0.4 mg l -1 ; high, medium, and low) and phosphorus (0.09, 0.03, 0.01 mg l -1 ; high, medium, and low) concentrations were paired and added to the water column. After 12 weeks, the combination of 1.80:0.01 N:P resulted in greater (P \ 0.01) total biomass and greater biomass for all plant tissues. Total biomass at the 1.80:0.01 N:P combination was 53% greater than biomass at all other combinations. The yield response of M. aquaticum was a quadratic function of tissue nutrient content. Yield was positively (r 2 = 0.82) related to increasing nitrogen content, whereas a negative (r 2 = 0.89) relationship was determined for increasing phosphorus content. We propose the negative relationship is due to increased nutrient competition and shading by algae resulting in reduced M. aquaticum growth. Tissue nutrient con- tent indicated that critical concentrations (1.8% nitrogen and 0.2% phosphorus) for growth were not attained except for nitrogen in plants grown in the 1.80:0.01 N:P combination. These data provide fur- ther evidence that M. aquaticum requires high levels of nitrogen to achieve nuisance growth. Survival through uptake of water column nutrients may be a mechanism for survival during adverse conditions, a means of long distance dispersal of fragments, or may offer a competitive advantage over species that rely on sediment nutrients.

Alterações ocorridas pelo manejo em Latossolo, Rondônia, Amazônia Brasileira

O objetivo deste trabalho foi avaliar atributos de fertilidade, frações da matéria orgânica, incluindo ácido fúlvico, ácido húmico, humina e matéria orgânica leve, densidade e volume total de poros, em um Latossolo Amarelo distrófico, sob cultura perene, pastagem e floresta amazônica em área de assentamento rural conhecida como Gleba Machadinho (RO). As coletas das amostras de solo ocorreram em 2004; foram amostradas as camadas superficiais do solo na profundidade de 0-0,1 m. Verificou-se melhoria na fertilidade dos solos sob culturas perenes, com diminuição da acidez e aumento dos teores de nutrientes. Não foi verificada diferença nos teores totais de carbono orgânico dos solos, porém variações nas frações orgânicas, ocorrendo menores teores de matéria orgânica leve e maior relação das substâncias húmicas alcalino solúveis em comparação à humina nos solos com culturas perenes. Nas áreas de pastagem, o pisoteio animal causou aumento da densidade do solo e redução do volume total de poros.

Use of olive mill waste mix as peat surrogate in substrate for strawberry soilless cultivation

The aim of paper was to evaluate the suitability of olive mill waste mixture (OMWM) as growth media for strawberry soilless cultivation. OMWM was used at the rate of 0, 25, 50, 75% (v/v) as peat substitute. In order to assess nutrient supply to plants by OMWM, the experimental design included fertigated (standard) and unfertigated sets. Some of the chemical and physical parameters of the growth media were analysed at the beginning and end of cultivation, while plant nutrient uptake was assessed by means of petiole- and leaf blade-tissue analyses for the main macro- (N, K, Ca, Mg, Na) and micro- (Fe, Mn, Zn, Cu) elements. Quantitative and qualitative assessments of yield were also made. Plants grown on OMWM amended substrate showed an initial slight phytotoxicity particularly at higher rate (75%) probably as a consequence of the high values of electrical conductivity recorded in the OMWM water extract. Successive water leaching caused by irrigation or fertigation reduced EC towards values compatible to strawberry cultivation. Yield data and tissues analyses showed that OMWM performed adequately as a substitute for peat and satisfied the plant nutrient needs in the fertigated trial. However, it appeared that nitrogen provided by OMWM was insufficient in achieving adequate yield in the unfertigated trial. The use of OMWM showed high compatibility in soilless strawberry cultivation being an effective and cheap alternative to peat; therefore, a realistic cost reduction for growers was evident. The relatively high amount of nutrients found in the growth media at the end of strawberry cultivation meant that it can be recycled in agriculture as soil amendment.

Application of Grey Prediction in a Solar Energy-Assisted Photocatalytic Low-Pressure Drying Process

An experimental solar energy-assisted photocatalytic low-pressure dryer (SEPLD) for batch food dehydration was developed and tested in an attempt to completely utilize green energy and contribute to reducing greenhouse gas emissions. The dryer consists of high-transmittance glass used to absorb heat from solar radiation, by which means the water content of food products was vaporized and removed using a low-pressure generation system. The performance test, sensory evaluation, and compound analysis showed that the SEPLD had a faster dehydration rate than other drying processes, and samples retained better color and higher amounts of nutrients. Due to the photocatalyst's (TiO2) action, samples dried using the SEPLD had lower bacterial counts. During the food-drying process, the weight of materials is usually calculated with the drying time to obtain dehydration equations that can be used to further assess the efficiency of the drying equipment and drying performance, such as the drying characteristic curves, drying rate, diffusion coefficient, and so on. However, some information was not easy to obtain during the drying process. We spent a lot of time measuring the water content of a large number of raw materials, especially for those raw materials that were difficult to dry. In this study, some seasonal fruits (pineapple [Ananas comosus L. Merrill], tomato [Lycopersicon esculentum], and star fruit [Averhoa carambola L.]) were selected for the drying tests at 40, 50, and 60°C in the SEPLD. The grey prediction methodology (GPM) was used with water content data to establish the SEPLD drying model, and this was applied to simulate the drying process at different temperatures. The results showed that the accuracy of 60°C drying by GM(1,1) of the GPM was better than the other prediction models. It also indicated that the GPM was a feasible way to simulate the drying process. A patent for the SEPLD was granted and issued in Taiwan.

Use of dried kapenta (Limnothrissa miodon and Stolothrissa tanganicae) and other products based on whole fish for complementing maize-based diets

Poor nutritional status both for children and adults is highly prevalent in those parts of sub-Saharan Africa where maize is a dominant staple. Maize is not a complete food, and if the child’s diet is only based on white maize, it may be deficient in calcium, vitamin A, vitamin C, vitamin B12, vitamin E, vitamin K, folate, riboflavin, pantothenic acid, niacin, potassium and iron. Inadequate intake of essential amino acids, vitamins, minerals and trace elements is associated with reduced growth, weakening of immunological functions and enhanced morbidity and mortality from infectious diseases, including measles, diarrhoeal diseases, parasite infestations, tuberculosis and HIV disease. Pregnant women and people suffering from infectious diseases, including HIV and tuberculosis, need a diet rich in protein and micronutrients. During pregnancy, growth requirements for the foetus must be covered. Infections lead to significant metabolic changes with enhanced rates of degradation or excretion of several nutrients including total protein, essential amino acids and vitamins. The diet must now contain higher amounts of nutrients than required by a healthy child or adult person in order to prevent the development of protein malnutrition and micronutrient deficiencies that will in turn easily lead to weakening of immunological functions. The purpose of the study was i) to analyse the nutrient composition of kapenta, and compare it to other animal products, and ii) to calculate the quantity of these products needed to cover the recommended dietary intake of several nutrients. Nutrient compositions of whole dried kapenta and Norwegian fish powder (fish protein concentrate type B) were found to be similar. It is shown that products made from whole fish are qualitatively superior to fish fillet and other animal products because they are much better sources of minerals and trace elements such as calcium, iron and zinc. They are also good sources of vitamin B12 and other bioactive substances such as membrane lipids, taurine and nucleic acids. Calculations of the improvements in nutrient intake if a maize-based diet is supplemented with minor amounts of a micronutrient- and protein-rich food like dried kapenta, or fish meal, was shown to give a balanced diet covering most of the nutrient requirements. It should be noted that patients suffering from chronic infectious diseases such as AIDS and tuberculosis have higher nutrient requirements (for protein, essential amino acids and several micronutrients) compared to healthy persons. Key words : Nutrition, children, maize, kapenta, fish-meal

The algae of Gaborone wastewater stabilization ponds: Implications for effluent quality

The types of algae found in the wastewater stabilization ponds in Gaborone were studied. Being the base of the food chain in any aquatic habitat, algae contribute significantly to the functioning and value of the ponds. The (liversit)' and abundance of the algae in the two pond systems at Broadhurst and Phakalane were determined. The nutrient composition i.e nitrates ami phosphates of the ponds were also determined. The ponds were found to have lower nutriellfs than the effluents from wastewater treatment plant. Phakalane ponds had higher amounts of nutrients compared to Broadhurst ponds. Blue-green algae (c)'anobacteria) and green algae were found to be the dominant algal groups. The Broadhurst ponds were dominated by green algae (58%) of all algae recorded followed by blue-green algae (23.8%), diatoms (9.2%) and euglenoids (8.5%). However, the blue-green algae were the most abundant group ill the Phakalane ponds (57.5%) followed by green algae (27%), diatoms (10.9%) and euglenoids (4.7%). Chlorella sp, Coelastrum combricum, C. microporium, Pediastrum boryanum and Scenedesmlls quadracauda were the most abandunt green algal species in the ponds. The blue-green algae Microcystis aeruginosa and M. flos-aquae were the most dominant species in both ponds, often forming heavy blooms. The blooms were the most striking feature of the ponds especially during the warm months. In this paper, the implications of the occurrence of algal blooms in the ponds and the use of the effluent for irrigation of edible plants and other uses are discussed. Key words : algal bloom, algal diversity, wastewater treatmellt, alga toxins, Microcysti

Seed Viability and Functional Properties of Broccoli Sprouts during Germination and Postharvest Storage as Affected by Irradiation of Seeds

The viability of broccoli seeds and functional properties, such as ascorbic acid, carotenoid, chlorophyll, and total phenol contents, of broccoli sprouts grown from irradiated seeds were evaluated. The seeds were irradiated using electron beam and gamma ray at doses up to 8 kGy. High germination percentages (>90%) were observed in seeds irradiated at < or =4 kGy, but the yield ratio and sprout length decreased with increased irradiation dose. Irradiation at > or =6 kGy resulted in curling of the sprout roots. Germinated seeds contained higher amounts of nutrients than raw seeds but the nutritional quality of sprouts decreased during postharvest storage. Radiation treatment hampered the growth of irradiated seeds resulting in underdeveloped sprouts with decreased ascorbic acid, carotenoid, and chlorophyll contents. In addition, the decrease in functional content of sprouts was more substantial in samples grown from high-dose (5 kGy) irradiated seeds than that of the low-dose (1 kGy) treated ones. Seed irradiation did not negatively affect the total phenol content of sprouts. In general, electron beam and gamma irradiation of broccoli seeds showed similar effects on the viability and functional properties of sprouts.

Expanding the menu for carnivorous plants: Uptake of potassium, iron and manganese by carnivorous pitcher plants

Carnivorous plants use animals as fertiliser substitutes which allow them to survive on nutrient deficient soils. Most research concentrated on the uptake of the prey's nitrogen and phosphorus; only little is known on the utilisation of other elements. We studied the uptake of three essential nutrients, potassium, iron and manganese, in three species of carnivorous pitcher plants ( Cephalotus follicularis LaBilladiere, Sarracenia purpurea L., Heliamphora nutans Bentham). Using relatively short-lived and γ-emitting radiotracers, we significantly improved the sensitivity compared to conventional protocols and gained the following results. We demonstrated the uptake of trace elements like iron and manganese. In addition, we found direct evidence for the uptake of potassium into the pitcher tissue. Potassium and manganese were absorbed to virtually 100% if offered in physiological concentrations or below in Cephalotus. Analysis of pitcher fluid collected in the natural habitat showed that uptake was performed here as efficiently as in the laboratory. The absorption of nutrients is an active process depending on living glandular cells in the pitcher epidermis and can be inhibited by azide. Unphysiologically high amounts of nutrients were taken up for a short time, but after a few hours the absorbing cells were damaged, and uptake stopped. Absorption rates of pitcher leaves from plants under controlled conditions varied highly, indicating that each trap is functionally independent. The comparison of minerals in typical prey with the plants’ tissues showed that a complete coverage of the plants’ needs by prey capture is improbable.

Phytoplankton assemblage of a small, shallow, tropical African reservoir

I measured physico-chemical properties and phytoplankton in the small, shallow tropical reservoir of Oyun (Offa, Nigeria) between January 2002 and December 2003. I identified 25 phytoplankton genera in three sampling stations. Bacillariophyceae dominated (75.3%), followed by Chlorophyceae (12.2%), Cyanobacteria (11.1%) and Desmidiaceae (0.73%). The high amount of nutrients (e.g. nitrate, phosphate, sulphate and silica) explain phytoplankton heterogeneity (p<0.05). Phytoplankton was abundant during the rainy season, but the transition period had the richest assemblage and abundance. Fluctuations in phytoplankton density were a result of seasonal changes in concentration of nutrients, grazing pressure and reservoir hydrology. The reservoir is eutrophic with excellent water quality and a diverse phytoplankton assemblage: fish production would be high. These conditions resulted from strategies such as watershed best management practices (BMPs) to control eutrophication and sedimentation, and priorities for water usage established through legislation. Additional measures are recommended to prevent oligotrophy, hypereutrophy, excessive phytoplankton bloom, toxic cyanobacteria, and run-off of organic waste and salts.

Micronutrients in Soils, Crops, and Livestock

Micronutrient concentrations are generally higher in the surface soil and decrease with soil depth. In spite of the high concentration of most micronutrients in soils, only a small fraction is available to plants. Micronutrients, also known as trace elements, are required in microquantities but their lack can cause serious crop production and animal health problems. Crops vary considerably in their response to various micronutrients. Brassicas and legumes are highly responsive to molybdenum (Mo) and boron (B), whereas corn and other cereals are more responsive to zinc (Zn) and copper (Cu). Micronutrient deficiencies are more common in humid temperate regions, as well as in humid tropical regions, because of intense leaching associated with high precipitation. Soil pH is one of the most important factors affecting the availability of micronutrients to plants. With increasing pH, the availability of these nutrients is reduced with the exception of Mo whose availability increases as soil pH increases. In most plant species, leaves contain higher amounts of nutrients than other plant parts. Therefore, whenever possible, leaves should be sampled to characterize the micronutrient status of crops. Deficiency symptoms for most micronutrients appear on the younger leaves at the top of the plant, whereas toxicity symptoms generally appear on the older leaves of plants. As summarized by Deckers and Steinnes, micronutrient deficiencies are widespread in developing countries, which have much poorer soil resources than the fertile soils of Europe and North America. Many of these areas lie in the humid tropics with extremely infertile, highly weathered, and/or highly leached soils, which are intensely deficient in nutrients. The rest of such soils are in the semiarid and areas adjacent to the latter, where alkaline and calcareous soil conditions severely limit the availability of micronutrients to plants. Frequently, the Cu, iron (Fe), manganese (Mn), Zn, and selenium (Se) levels in forages, which are sufficient for optimum crop yields, are not adequate to meet the needs of livestock. Selenium is a trace mineral, which is not required by plants, and maximum forage yields can be obtained on soils with very low amounts of soil Se. However, if animals are fed feed crops and forages with low Se, they could suffer from serious muscular disorders and other diseases. White muscle disease caused by Se deficiency is the most common disorder and is found in calves and lambs. Sufficiency levels of micronutrients for crops have been discussed in relation to the animal requirement.

Benthic foraminifera from polluted marine environment of Sulaibikhat Bay (Kuwait)

Quantitative analyses of recent benthic foraminiferal assemblages (living and dead) were carried out on the surface sediments of Sulaibikhat Bay. Marked contrast in foraminiferal assemblages between the shallow tidal mudflats and the deep tidal channel and their relation to the extent of pollution were observed. Cluster analysis of quantitative data on the distribution of foraminiferal tests revealed three assemblages that depend mainly on the intensity of pollution; (1) a highly polluted tidal flat assemblage, (2) normal (or less polluted) mud flat assemblage and, (3) tidal channel and subtidal assemblage. The highly polluted assemblage characterized by a drop in species densities (< 100 tests/20 cm(3) sediment) but with high average diversity (5.8 Yule-Simpson Index). The microfauna of the less polluted flat displays relatively lower diversity (4.6) but high density of tests (47.2% of the total picked tests). The most abundant species of this assemblage is Ammonia tepida, displays its maximum density in this assemblage. Ammonia tepida drops in density from 17.12% to 3.07% in the polluted assemblage. Tidal channel foraminiferal assemblages should normally display lower diversities than those of tidal flats, because tidal current in the channels tend to wash away most nutrient materials. However, this is not the case of the present study area which could be due to environmental setting of the Sulaibikhat Bay in which tidal currents bring in exceptionally high amounts of nutrients from Shatt Al-Arab Estuary and in which the tidal flats are strongly and adversely polluted.