Soil-water Medium Research Articles

Pertumbuhan Mikroalga Chlamydomonas dalam Medium Beneck dan Air Tanah yang Mengandung Insektisida Berbahan Aktif Klorpirifos

The research of insecticide effect to the growth of genus Chlamydomonas had been done. Research was experimental study with block random design to 9 concentrations of chlorpiriphos containing insecticide in Beneck and soil water media i.e. 0 (control), 0.05, 0.10, 0.15, 0.20, 0.25, 0.30, 0.35, and 0.40%. Observations were done for 35 days. Friedman test showed that there were some effects of media and insecticide concentrations on cell numbers of Chlamydomonas (cell/ml) in culture (p>0.05). Dunnets test showed that mean of cell numbers of Chlamydomonas (cell/ml) differ (on p>0.05) and very differ (on p>0.01) on every concentrations in Beneck and soil water media. Insecticide could reduced the cell size of Chlamydomonas, yet increased the number of cells on 0.05--0.30% concentrations in Beneck medium, and 0.05--0.20% concentrations in soil water medium. On peak culture, insecticide with 0.10% concentration produced the highest cell numbers i.e. 21,179,167 cell/ml in Beneck medium, and 4,087,500 cell/ml in soil water medium.

Surface flux and vertical profile of dimethyl sulfide in acid sulfate soils at Cudgen Lake, northern New South Wales, Australia

A dimethyl sulfide (DMS) vertical concentration profile and DMS surface emission flux were quantified in undisturbed acid sulfate soils (ASS) at Cudgen Lake on the north coast of New South Wales, Australia. A deuterated internal standard was used to account for soil adsorption characteristics. The DMS vertical concentration profile increased exponentially from 0.6 m depth to the surface layer. This profile reflected the adsorption properties of the ASS horizons present and the experimentally determined octanol/water partition coefficient for DMS of 1.36, suggesting that DMS would be mobilised in the soil water medium for upward translocation in time due to surface evaporation. The organic material in the oxidised ASS crustal layer had a chemically strong adsorption affinity for DMS, which appeared to restrain its emission from surface soil particles to the atmosphere. The seasonally averaged DMS surface flux estimate from the Cudgen Lake ASS was 9 ng S m−2 min−1, which is relatively low by comparison to DMS fluxes reported from other wetland soils such as salt-marshes and acidic peat bogs. The worldwide annual average DMS emission from ASS was estimated to be 1.14 × 10−3 Tg S, which is globally insignificant by comparison to DMS emission from the world's oceans.

Pedostructure Concept: A New Paradigm for Quantifying Soil Structural Characteristics

Characterization of the internal organization of the soil can aid the quantification of soil structural characteristics, and also enhance the understanding of the soil processes for adequate agricultural and environmental soil management. However, the current soil physics approach describes soil structure and its hydraulic properties independent from the internal organization and hydro-structural functioning of the soil medium. The pedostructure concept is a new paradigm in soil structural analysis that is aimed at understanding the hydrostructural characterization, behaviour, configuration, and interactions of the soil-water medium, by taking into account the internal organization and functionality, with respect to water flow, of the soil.

Ultrastructural Alterations in Lepocinclis acus (Euglenophyta) Induced by Medium with High Organic Matter Content

Ultrastructural changes induced by exposure to excess of organic matter were studied in Lepocinclis acus (ex Euglena acus). The cells isolated from the Matanza River, Buenos Aires, Argentina, were grown in soil water medium. When transferred to medium enriched with Bacteriological Peptone OXOID®, marked body deformation and a significant shortening and widening of the cells was observed. These changes were unexpected in a species with quite rigid cells, a condition previously shown in studies of the pellicle fine structure. Transmission electron microscopy observations suggest that cellular deformation might be facilitated by an increase in strip number, whereas in the original strips normal ultrastructure was maintained. An increase in number and volume of paramylon grains and vacuoles, as well as the presence of membrane whorls in vacuoles was observed. The fine structure of organisms grown in medium with and without organic matter enrichment was compared, and the systematic and ecological importance of morphological changes triggered by cell deformation was discussed.

A framework for soil-water modeling using the pedostructure and Structural Representative Elementary Volume (SREV) concepts

Current soil water models do not take into account the internal organization of the soil medium and consequently ignore the physical interaction between the water film at the surface of solids that form the soil structure and the structure itself. In this sense, current models deal empirically with the physical soil properties, which are all generated from this soil water and soil structure interaction. As a result, the thermodynamic state of the soil water medium, which constitutes the local physical conditions of development for all biological and geochemical processes within the soil medium, is still not well defined and characterized. This situation limits modeling and coupling the different processes in the soil medium since they all thermodynamically linked to the soil water cycle. The objective of this article is to present a complete framework for characterizing and modeling the internal soil organization and its hydrostructural properties resulting from interaction of its structure with the soil water dynamics. The paper builds on the pedostructure concept, which allowed the integration of the soil structure into equations of water equilibrium and movement in soils. The paper completes the earlier framework by introducing notions of soil-water thermodynamics that were developed in application to the concept of the Structural Representative Elementary Volume (SREV). Simulation of drainage after infiltration in the Yolo loam soil profile, as compared to measured moisture profile using the measured soil characteristic parameters, showed a high degree of agreement. This new modeling framework opens up new prospects in coupling agro-environmental models with the soil medium, recognizing that the soil organization, hydro-structural, and thermodynamic properties are the foundation for such coupling.

Ultrastructural alterations in Phacus brachykentron (Euglenophyta) due to excess of organic matter in the culture medium

Morphological and ultrastructural changes induced by exposure to excess of organic matter were analyzed in Phacus brachykentron (Pochm.). The cells were isolated from sites in Matanza River, Buenos Aires, Argentina, which have a high degree of organic matter contamination coming from waste waters discharges of the meat industry. Master strains were cultured on soil water medium and a toxicity bioassay was performed. As a result of the enriched medium, several morphological and ultrastructural cellular alterations were observed by optical, scanning, and transmission electron microscopy. Among these, we can point out changes in cell dimensions, remarkable widening of some pellicle bands, increased number and volume of paramylon grains, displacement of the nucleus from the central to the lateral position, some chloroplasts with their thylakoids disordered, and cell lysis. The response to organic enrichment was very fast, i.e. during the 48h of the bioassay. Therefore, any significant increase of organic matter would rapidly affect wild euglenoids. Our results suggest that the alterations observed, such as the presence of large intracellular paramylon bodies or the deformation of euglenoid cells in natural samples, have the potential to be used as environmental bioindicators.

Humic acid/polypyrrole on a paraffin‐impregnated graphite electrode and its use in arsenic extraction

AbstractA novel and simple electrode with rapid preparation was developed with humic acid (HA) and polypyrrole (PPy) films. The method for modified electrode preparation embraced the abrasive transfer technique on a paraffin‐impregnated graphite electrode (PIGE) followed by the electrochemical incorporation of a PPy polymeric film upon bare PIGE and PIGE/HA electrodes. Cyclic voltammetry, electrochemical impedance spectroscopy, and chronoamperometry were used for the study of the modified electrodes. Morphological characterization was performed by scanning electron microscopy. The obtained results demonstrated that the presence of HA did not affect the electrical properties of the system but indeed provoked changes in the polymer morphology, turning it more granular. Next, PIGE/HA/PPy was tested in arsenic solutions [As(V)] because arsenic contamination of water is an important worldwide environmental issue because of the sources of arsenic contamination of water come from both natural processes and anthropogenic activities. The modified electrode displayed good and reversible extraction properties toward the analyte in acid medium and was 18% more efficient than a previously reported PPy‐modified electrode (PIGE/PPy). From an environmental standpoint, this novel application of conductive polymer properties with the chelating capacity of humic substances constitutes a first step in the development of more efficient technologies for the removal of contaminants present in soil–water media. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

Hydrostructural characteristics of two African tropical soils

SummaryThis paper describes the characteristic shrinkage curve of a soil as it dries. It also introduces a new method to measure specific soil moisture states such as permanent wilting point and field capacity using the shrinkage curve. The model considers the soil fabric as a non‐rigid, aggregated and unsaturated soil water medium. Its functional parameters (defined as pedohydral parameters) are the independent parameters of the shrinkage curve, which defines two major aspects of the structure of the fabric: (i) the volumetric functional elements of the soil fabric, and (ii) the arrangement of solid, water and air as functions of water content.Two African tropical soils were characterized and analysed according to a structural model with parameters of their shrinkage curve. The parameters of four soil horizons for the two soil types were determined continuously along their shrinkage curves. They were then used as descriptive variables representing the soil's hydrostructural behaviour in a canonical variate analysis, the results of which showed the A horizons to be distinct from the lower horizons, which appear as continua down the profiles. Analysis of the results reveals the importance of the clay and of the iron/clay ratio in the hydrostructural properties of the two soils. Transitional points of the shrinkage curve matched well some particular moisture states of the water potential curve, such as wilting points and field capacities. A more precise method of calculating water‐holding characteristics and other structural properties such as air capacity and swelling index can be obtained from the characteristic shrinkage curve.

Characterizing Nonrigid Aggregated Soil–Water Medium Using its Shrinkage Curve

The properties of the soil–water medium are presented in the literature independent of its internal organization and operation. The objective of this study is to develop and test a conceptual model that used a continuously measured shrinkage curve (SC) to describe the functional organization of the soil–water medium. In this model, two functional porosities (micro and macro) are delineated and quantified by the SC. In addition, the equilibrium for four functional water pools is represented and parameterized by the SC. A set of eleven parameters was found necessary to model the seven phases of the SC and to describe the corresponding soil hydrostructural changes. A method to accurately obtain the parameters of this model by a specific analysis of the continuously measured SC is demonstrated. Examples of continuously measured and modeled SCs according to the pedostructure model (PS) are presented and discussed.

Characterizing Nonrigid Aggregated Soil–Water Medium Using its Shrinkage Curve

The properties of the soil–water medium are presented in the literature independent of its internal organization and operation. The objective of this study is to develop and test a conceptual model that used a continuously measured shrinkage curve (SC) to describe the functional organization of the soil–water medium. In this model, two functional porosities (micro and macro) are delineated and quantified by the SC. In addition, the equilibrium for four functional water pools is represented and parameterized by the SC. A set of eleven parameters was found necessary to model the seven phases of the SC and to describe the corresponding soil hydrostructural changes. A method to accurately obtain the parameters of this model by a specific analysis of the continuously measured SC is demonstrated. Examples of continuously measured and modeled SCs according to the pedostructure model (PS) are presented and discussed.

Chemical Corrosion in Cast Iron in Soil-Water Medium

Grey cast iron metal strips were allowed to rust in varying compositions of soil-water media under the controlled environment. The process of corrosion was monitored by non-electrochemical method. Assessment of the extent of corrosion was carried out, both visually and by the method of weight loss coupons. It was found that a 80:20 weight:volume percent (w/v %) composition caused the most severe case of corrosion over a period of seven days. It was also observed that the corrosion in cast iron obeyed the relation, D = ktn [10]. The value of ‘n’ increased as corrosion became more severe. Gravimetric analysis and evidence from the Scanning Electron Microscopy (SEM) proved that γ-FeOOH was one of the intermediates of corrosion in grey cast iron in soil-water media. An attempt has also been made to propose a mechanism for the corrosion in cast iron strips in soil-water media. It was found to be consistent with the one proposed by McEnaney and Smith [11].

First Report of a Putative Cyanophage, Mc-1, of Microcoleus Sp.

Abstract A current review (1) lists 21 cyanophages of coccoid and filamentous heterocystic and non-heterocystic blue-green algae (BGA). The capsid diameters of these viruses range from 50-90 nm, and none have been previously reported for Microcoleus,a sheath-producing, filamentous, surface colonizing BGA (Fig. 1), of the order Oscillatoriales, and class Cyanophyceae (= Cyanobacteria). From a freshwater culture of Microcoleussp. we report here a putative cyanophage with a side-to-side hexagonal capsid diameter of 140 nm, based on measurements from thin sections of algal filaments prepared for transmission electron microscopy (TEM). An earlier report (2) documented the ultrastructure of mucilage secretion, and its role in sheath, trichome and filament formation in an isolate of the BGA Microcoleus sp. grown in soil-water medium. Now we report large cyanophage-like particles in a majority of cells making up the trichomes. These putative hexagonal viral capsids (Figs. 2-5) are mainly clustered in the center or to one side of the nucleoplasm.

Microcosms as Islands: A Test of the Macarthur‐Wilson Equilibrium Theory

A test of the MacArthur—Wilson equilibrium model of island biogeography was conducted using aquatic microcosms as island analogs. Fifty 400—mL beakers containing 300 mL of sterilized soil—water medium and 50 2000—mL beakers containing 1800 mL of medium were inoculated with replicated subsets of species from a species pool consisting of green, blue—green, and golden algae, ciliates, a rotifer, a dinoflagellate, and euglenoids. These species were added at two different average rates over a 28—wk period, resulting in four replicated sets of 25 insular communities. Community reorganization (turnover) was shown to occur, as well as relatively constancy in species richness for each beaker category, indicative of equilibrium. Contrary to the MacArthur—Wilson prediction, small microcosms had significantly higher species richness values than large microcosms. Microcosms subjected to the higher of the two invasion rates had significantly higher species richness values than those of the lower rate categories, primarily due to the influence of transient species. Early divergence into two broad community types is documented, suggestive of at least two stable community states that transcend microcosm categories.

Zoospore Induction and Activity in Fritschiella tuberosa Iyengar (Chlorophyceae)

Zoospore induction, morphology, and movement were compared in nine cultures of Fritschiella tuberosa Iyengar collected worldwide. Submerging this terrestrial alga in soil water medium induced zoospore release during the following light period. Zoospores were produced one per cell in all photosynthetic parts of the thallus. Zoospores were anteriorly quadriflagellate and, although lacking eyespots, they exhibited positive phototaxis. Zoospores varied from 4.4 to 13.1 /'m in diameter. Within each culture the sizes formed a normal distribution. All nine cultures had been designated as Fritschiella tuberosa by their respective isolators. The uniformity found in zoospore behavior and morphology supported these identifications. Fritschiella tuberosa Iyengar has been reported from several locations around the world (Table 1). Samples from all these localities were obtained and grown under controlled conditions as a means of comparing these cultures. Since the discovery of this green alga in 1932, F. tuberosa has stirred great interest evolutionarily due to its advanced morphology and its growth in a terrestrial habitat (Fott 1965, Fritsch 1945, Pickett-Heaps 1975, Scagel et al. 1965). The thallus is differentiated into distinct parenchymatous prostrate and filamentous upright photosynthetic portions as well as nonphotosynthetic rhizoidal filaments (Iyengar 1932). When conditions are favorable, especially during periods of flooding, F. tuberosa has the ability to reproduce quickly and with great numbers of propagules, which have been shown to be asexual zoospores (Hopkins 1977). This characteristic and the compact nature of the prostrate thallus, which reduces desiccation, are important aspects of the success of this alga in invading the terrestrial habitat. This study analyzed the production of zoospores, their morphology, and their subsequent activity. A comparison of these aspects among the nine geographically diverse collections was undertaken as one means of assessing the monospecificity of these collections, all identified as Fritschiella tuberosa, and as a means of learning more about asexual reproduction in this alga. MATERIALS AND METHODS. The source of each F. tuberosa culture is listed in Table 1. The unialgal clones were maintained in 30 ml capped culture tubes on 1.5% Difco algal agar supplemented with soil water in a 12:12 L:D regime, with

Conjugation and mating competency inSirogonium sticticum(Chlorophyta, Zygnematales)

Eight unialgal strains of Sirogonium sticticum (J. E. Smith) Kütz. were studied to compare their conjugation response. These strains were cultured in soil-water medium with a light intensity of 3,500–4,000 1x on a 16:8 h light-dark cycle at 20° ± 1°C. Chlorophyll content was used as an indirect measurement of growth to determine the phase of the growth cycle in which conjugation is initiated. Time in weeks to mating competency among the strains ranged from 3 to 6 weeks. This followed the end of log-phase growth from 0 to 2 weeks based on weekly observations. Variation in the intensity of conjugation was related to the duration of the sexual response. This duration ranged from 2 weeks, resulting in less than 0·1% sexual cells, to 7 weeks with 5·3% sexual cells.

A New Asexual Cycle in a Pediastrum simplex Strain

In a freshly prepared soil-water medium, a Pediastrum simplex strain yielded a previously unreported asexual cycle. This cycle, requiring 2-5 days, began with motile cells released directly from azygotes Each motile cell developed into a flattened four-cornered polyeder The polyeder contents divided internally into four cells that remained together inside the polyeder cell wall to form a flat four-cornered colony After a short period of growth, the colony cells released motile cells directly into the culture medium Each motile cell developed into a flattened four-cornered azygote to complete the cycle The appearance of azygotes and polyeders of the fast cycle was identical After cultures aged for 6-8 mo, or when cultures were subjected to low temperatures, pH extremes, or contaminating algae, the fast-cycle cells were replaced by slow-cycle cells The latter, identical with an asexual cycle reported by Davis (1967) involving spherical four-spined azygotes produced by typical colony cells, required 1...

The ultraviolet radiosensitivity of Oedogonium cardiacum cells at various stages of the cell cycle

The ultraviolet (UV) radiosensitivity as measured by the loss of reproductive capacity of synchronously growing Oedogonium cardiacum cells cultured under different environmental conditions has been measured during the first generation cycle and compared to the results for ionizing radiation. Both radiosensitivity patterns were approximately the same in shape exhibiting a maximum resistance in the S period and a minimum in the G 2 . Following X-radiation, D 0 and n values varied with age by a factor of 7 and 40 respectively. In contrast, following UV-radiation D 0 varied by a factor of 2·5 and n remained essentially constant. A variation in the magnitude of the UV radiosensitivity was observed between cells cultured in inorganic medium bubbled with 3% CO 2 in air and illuminated with fluorescent lights and cells cultured in diphasic soil-water medium under natural illumination. At all stages of the cell cycle, cells collected from stock cultures grown in the more natural habitat were approximately twice as resistant. A seasonal variation in UV radiosensitivity was also observed in cells collected from this latter group.

Germination in Pithophora Akinetes

The green alga Pithophora was described at the close of the last century by Wittrock (1877). Wittrock noted that akinetes germinate parallel to the long axis of the cells, whereas later studies of Mothes (1930) and Ernst (1908) indicated that germination was at right angles to the long axis of the cells. Since past observations concerning akinete formation and development have been of a general nature, and little is known of the specific conditions under which these phenomena occur, a germination study of Pithophora varia Wille under controlled culture conditions was undertaken (Neal, 1965). MATERIALS AND METHODS The specific identity of the Indiana culture strain used was determined by Dr. G. W. Prescott to be Pithophora varia Wille. This strain was cultured, in mass, in soil-water medium modified from standard culture techniques (Pringsheim, 1946) only by autoclaving at 250 F. In addition, Bold's basal medium (Bishoff & Bold, 1963) was found to support rapid growth when the quantity of NaNO3 was doubled. Akinetes were formed in abundance in cultures three or more weeks old in both media. Cultures previously maintained in an 18 hr day length environment at 25 C were placed in a dark box at 21 C seven days prior to the experimental period. Square polystyrene utility boxes containing suspended filaments with mature akinetes were prepared. These were either unpainted, to allow light to enter from all directions, or painted in a manner to admit light through a small window from either one direction, or from two opposite directions. The boxes with mature akinetes were then placed in BOD incubators with a medium of soil-water supernatant at 28 C (determined to be the optimum temperature for germination by a series of preliminary studies) and light intensity of 420 ft-c provided by 30 w, cool, white, fluorescent lamps. In like manner, a set of controls was prepared under identical conditions in dark containers.

Division Rates of Salt Marsh Diatoms in Relation to Salinity and Cell Size

Fourteen species of motile pennate diatoms obtained from a Georgia salt marsh were cultured under uniform conditions (19°—20°C, 16,000—23,000 lux) in soil—water medium at salinities between 1 and 68 %. All species grew well over at least the range of 10 to 30%; several species grew well over the entire salinity range. At 20 % the division rate was either maximal or close to maximal. Diatom preconditioned to particular salinities in general divided at the same rate as those not preconditioned. Maximum rates for the 14 species ranged from 0.6 to 3.2 divisions/day. These maximum rates had highly significant correlations with both the logarithm of the cell volume and the square root of cell area/cell volume. Least squares regressions were computed for these relationships with volume expressed in μ3 and area in μ2. Maximum number of divisions per day = 3.75 — 0.7 (log volume) =—0.01 + 1.64 (area/volume)½

A MORPHOLOGIC AND GENETIC STUDY OF GONIUM PECTORALE

THE MOST FREQUENTLY encountered species of Gonium is the 16-celled G. pectorale Muller, which was one of the original species described by 0. F. Muller in 1773 when he erected the genus. By 1838 it was the only species still considered to be a member of the genus, and it thus became the lectotype of Gonium (Ehrenberg, 1838). Previously, Bory (1824) had described a new monotypic genus, Pectoralina, whose type, P. hebracia, Ehrenberg (1838) and others have considered synonymous with G. pectorale. In 1866 Diesing placed G. helveticum Perty in his new genus Glenogonium, but Warming (1876-77) and Biitschli (1884) have referred this species to G. pectorale. Pocock (1955), in her study of the genus Gonium in North America, considered G. pectorale as comprised of two varieties, variety pectorale and variety praecox. The variety praecox has comparatively small, usually pale-green colonies composed of slightly elongated cells with the apex wider than the base. This varietal name refers to the precocious development of daughter colonies, while the mother colony is still quite small. GENERAL TECHNIQUES. Throughout this investigation, single colony isolations were made with a glass capillary pipette using a dissection microscope equipped with substage, darkfield illumination. The cultures were maintained in Pringsheim's soil-water medium (Starr, 1956) or in a modified Beijerinck's medium (table 1) to which were added 10 per cent soil-water supernatant and 1-1.5 per cent agar. Active growth of the cultures occurred at 200C. at 200250 ft.-c. intensity (provided by 40-w. cool-white fluorescent lamps) on a 16 hr. light-8 hr. dark cycle. Stock cultures received illumination of about 75 ft.-c. intensity and were transferred every 6-8 weeks. The strains used in this study were obtained from field collections and from soil-cultures. The latter were made by covering dry mud samples in a dish with glass-distilled water and placing the dishes under the conditions described above. The colonies were isolated 1-4 days after the water had been added. Colonies isolated from one collection site at any one time are considered members of the same