Effects of Excess Copper on Growth of Wild Rice (<Emphasis Type="Italic">Zizania palustris</Emphasis>) Seedlings Tested in Reconstituted and Natural Waters

Dissolved copper was toxic to wild rice (Zizania palustris) seedlings when exposed in water from the seed collection site of Swamp Creek, Crandon, Wisconsin, USA, and in laboratory-prepared artificial or reconstituted water. Seeds for the study were harvested, then held through a portion of dormancy, in Swamp Creek. After 60 days they were shipped to a laboratory, chilled, and tested with copper after germination. The end point of the tests was net gain in wet weight of the seedlings; additionally, a pronounced reduction in root development was observed. Using measured concentrations, the lowest no-observable-effect concentration (NOEC) in our study was 37 g/liter in Swamp Creek water and the lowest-observable-effect concentration (LOEC) was 59 g/liter. However, it appeared that there was a point at which concentrations of copper above 400 g/liter did not result in any measurable effect or exhibit a definitive dose–response. Because the results in Swamp Creek water were more relevant to the possibility of local metals additions and the association of reduced seedling growth by copper was more powerful in this water, we derived an equation to express the relationship between copper concentration and toxicity for Swamp Creek water. As an example, we would expect a 3.0% reduction in seedling growth at 5.0 g/liter copper. Seedling roots were particularly affected and the resultant plants may be less well anchored and more susceptible to dislodging than plants not exposed to copper. Further refinement of the methodology may be used to address effects of other contaminants impacting rice beds in North America. This study was conducted while the first author was employed by the U.S. Geological Survey, Mid-continent Ecological Science Center, Fort Collins, Colorado     

Investigation of naphtalene sulfonate compounds sorption in a soil artificially contaminated using batch and column assays

In the present work desorption tests of an artificially contaminated soil by naphatelene sulphonated compounds have been carried out by soil washing realised by water at different pH: Naphtalene-1,5-disulfonic acid (1-5 NDS), 2-naphthol-6,8 disulphonic acid (G-acid) and sodium beta-naphtalene-sulphonate (beta-salt) have been selected as more representative organic compounds present in the ex industrial site of ACNA (Cengio, SV, Italy) in which very serious contamination levels of several pollutants are present both in the soils and surface waters. Equilibrium batch tests have been carried out in order to find the best operative condition in column washing tests. The obtained results can be considered very preliminary but useful to arrange a next experimental work that will be realised on real contaminated soils.     

Isotopic composition, growth rates and biological behaviour of Chamelea gallina and Callista chione from the Bay of Trieste (Italy)

Shells of the bivalve molluscs Chamelea gallina L. and Callista chione L. from the Bay of Trieste (northern Adriatic) were analysed for their oxygen and carbon isotopic composition. The main purpose of this study was to obtain detailed information on the biological behaviour and, particularly, on the growth rates and the settlement time of these two species. Isotopic measurements were carried out on "spot" samples collected from the umbo to the ventral margin of each shell. The results obtained from nine specimens of C. gallina (plus some 20 specimens studied only for the isotopic composition of their initial umbo and for the last section of their ventral edge) and from two specimens of C. chione allow the following conclusions: (1) the calcium carbonate of C. gallina shells is not deposited under isotopic equilibrium conditions with the environmental variables (temperature and oxygen isotopic composition of seawater); (2) this species usually initiates precipitation of carbonate during the springtime, although some late summer-early autumn generation also occurs; (3) the rate of calcium carbonate deposition decreases with increasing age, and the overall accretion rate is a rather slow one; (4) there is a negative correlation between the carbon isotopic composition and the size of each shell; (5) the mean growth rate of the shells can be easily evaluated according to the oxygen isotopic composition of the spot measurements; (6) the specimens of C. chione do not precipitate the calcium carbonate of their shells in isotopic equilibrium with environmental conditions; (7) their accretion rate is rather fast during the first years of their life and progressively and considerably reduced after about 5 years; (8) the carbon isotopic composition of these shells does not show the marked evolution towards more negative values shown by C. gallina, suggesting that neither respiratory CO₂ nor carbon species derived from the oxidation of organic matter are systematically used for the precipitation of shell carbonate; and (9) a marked preference for the warmer half of the year is shown by the oldest specimen of C. chione (12 years).     

Motility of cryopreserved spermatozoa for the ecotoxicological evaluation of aquatic environments

A new approach to environmental studies was investigated by the authors, who propose the use of cryopreserved biological systems in ecotoxicological bioassays. The feasibility of spermiotoxicity tests using cryopreserved semen of the sea bream Sparus aurata, with sperm motility parameters as the endpoint, was evaluated. Thawed sperm was incubated in environmental samples (sediment elutriate and dumpsite leachate) and in a reference toxicant (cadmium) at scaled concentrations. Motility was then evaluated by video-microscopy using both visual and computer-assisted analyses. Activation time, sperm motility and velocity and motility duration were assessed on thawing and at the end of the incubation time, and the difference with respect to the control was statistically evaluated. All the endpoints of the bioassay proved to have good sensitivity even at the highest dilutions of the tested matrices. Observed differences in the sensitivity thresholds of the endpoints were considered to be representative of different aspects of sperm physiology. Therefore the proposed bioassay is a promising starting point for the development of toxicity tests that are increasingly tailored to the needs of ecotoxicology and environmental quality evaluation strategies for aquatic environments.     

Microbes to clean indoor pollutants

Formaldehyde is a dangerous indoor pollutant which is introduced in house by common objects such as furniture. Effective microorganisms have the very interesting ability to degrade some pollutants. Here, we tested the removal of formaldehyde and aromatic aldehydes using effective microorganisms including yeast, lactic acid bacteria, and photosynthetic bacteria. Formaldehyde was quantified by GC–MS of formaldehyde dinitrophenylhydrazone. Other aldehydes were analyzed by GC–MS. Results show that effective microorganisms remove 70–100 % of formaldehyde, benzaldehyde, and 4-methylbenzaldehyde in about a week. Experiments on chipboard panels indicate the possibility to decrease the amount of formaldehyde emission by furniture. This is the first report on the removal of formaldehyde by effective microorganisms, to our best knowledge.     

Global potential net primary production predicted from vegetation class, precipitation, and temperature

Net primary production (NPP), the difference between CO2 fixed by photosynthesis and CO2 lost to autotrophic respiration, is one of the most important components of the carbon cycle. Our goal was to develop a simple regression model to estimate global NPP using climate and land cover data. Approximately 5600 global data points with observed mean annual NPP, land cover class, precipitation, and temperature were compiled. Precipitation was better correlated with NPP than temperature, and it explained much more of the variability in mean annual NPP for grass- or shrub-dominated systems (r2 = 0.68) than for tree-dominated systems (r2 = 0.39). For a given precipitation level, tree-dominated systems had significantly higher NPP (approximately 100-150 g C m(-2) yr(-1)) than non-tree-dominated systems. Consequently, previous empirical models developed to predict NPP based on precipitation and temperature (e.g., the Miami model) tended to overestimate NPP for non-tree-dominated systems. Our new model developed at the National Center for Ecological Analysis and Synthesis (the NCEAS model) predicts NPP for tree-dominated systems based on precipitation and temperature; but for non-tree-dominated systems NPP is solely a function of precipitation because including a temperature function increased model error for these systems. Lower NPP in non-tree-dominated systems is likely related to decreased water and nutrient use efficiency and higher nutrient loss rates from more frequent fire disturbances. Late 20th century aboveground and total NPP for global potential native vegetation using the NCEAS model are estimated to be approximately 28 Pg and approximately 46 Pg C/yr, respectively. The NCEAS model estimated an approximately 13% increase in global total NPP for potential vegetation from 1901 to 2000 based on changing precipitation and temperature patterns.     

Thermodynamics of irreversible processes and quantum field theory: An interplay for the understanding of ecosystem dynamics

Ecological modelling has not yet received from basic “hard” sciences, like conventional physics and chemistry, an adequate conceptual support. Mechanistic simulation techniques are very far from achieving a satisfactory understanding of ecosystem dynamics.     

Mechanical,Barrier and Antioxidant Properties of Chitosan Films Incorporating Cinnamaldehyde

Chitosan films (CF) [1 and 2% w/v] alone and with cinnamaldehyde (CNE) [0.25, 0.5 and 1% v/v] were prepared using an emulsion method, and the obtained films were characterized in terms of water vapor permeability (WVP), water solubility and optical, mechanical and antioxidant properties. The incorporation of CNE at 1% (v/v) significantly decreased the water solubility of the film by approximately 4% for the 1 and 2% CF films, whereas the WVP increased (2.5–3.5 times). The incorporation of CNE (0.25 and 0.5%) into 2% CF significantly increased the tensile strength (TS) (62 and 34%, respectively) and the percent elongation (%E) values, 26, 30 and 52% for CF that contained 0.25, 0.5 and 1% CNE, respectively. The largest value of the elasticity modulus (EM) was observed for 2% CF with 0.25% CNE. All films exhibited a yellow appearance (b*), but the CNE content had a marked impact on the coloration of the films. The CNE recoveries of the CF films (1 and 2%) with 1% of CNE were high (43 and 67%). The antioxidant activities indicated that the incorporation of 1% CNE into CF films (1 and 2%) increased the antioxidant activity. The protective effects of the films with and without CNE on erythrocytes were very strong (36–72% hemolysis inhibition). These results suggest there are potential applications for CF-CNE films as active packaging for the preservation of food products.     

Remediation of phenanthrene-contaminated soil by simultaneous persulfate chemical oxidation and biodegradation processes

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous compounds with carcinogenic and/or mutagenic potential. To address the limitations of individual remediation techniques and to achieve better PAH removal efficiencies, the combination of chemical and biological treatments can be used. The degradation of phenanthrene (chosen as a model of PAH) by persulfate in freshly contaminated soil microcosms was studied to assess its impact on the biodegradation process and on soil properties. Soil microcosms contaminated with 140 mg/kg_{DRY SOIL} of phenanthrene were treated with different persulfate (PS) concentrations 0.86–41.7 g/kg_{DRY SOIL} and incubated for 28 days. Analyses of phenanthrene and persulfate concentrations and soil pH were performed. Cultivable heterotrophic bacterial count was carried out after 28 days of treatment. Genetic diversity analysis of the soil microcosm bacterial community was performed by PCR amplification of bacterial 16S rDNA fragments followed by denaturing gradient gel electrophoresis (DGGE). The addition of PS in low concentrations could be an interesting biostimulatory strategy that managed to shorten the lag phase of the phenanthrene biological elimination, without negative effects on the physicochemical and biological soil properties, improving the remediation treatment.