Effects of Terrestrial Buffer Zones on Amphibians on Golf Courses

A major cause of amphibian declines worldwide is habitat destruction or alteration. Public green spaces, such as golf courses and parks, could serve as safe havens to curb the effects of habitat loss if managed in ways to bolster local amphibian communities. We reared larval Blanchard's cricket frogs (Acris blanchardi) and green frogs (Rana clamitans) in golf course ponds with and without 1 m terrestrial buffer zones, and released marked cricket frog metamorphs at the golf course ponds they were reared in. Larval survival of both species was affected by the presence of a buffer zone, with increased survival for cricket frogs and decreased survival for green frogs when reared in ponds with buffer zones. No marked cricket frog juveniles were recovered at any golf course pond in the following year, suggesting that most animals died or migrated. In a separate study, we released cricket frogs in a terrestrial pen and allowed them to choose between mown and unmown grass. Cricket frogs had a greater probability of using unmown versus mown grass. Our results suggest that incorporating buffer zones around ponds can offer suitable habitat for some amphibian species and can improve the quality of the aquatic environment for some sensitive local amphibians

Pesticides Removal Using Actinomycetes and Plants

The γ-hexachlorocyclohexane (γ-HCH, lindane) is an organochlorine pesticide used in agriculture and medicine to world level. It has a big tendency to bioaccumulation into the environment so is listed as a priority pollutant by the US EPA. Hence the development of new technologies to remediate these sites using microorganisms is every time more necessary. The actinomycetes are Gram-positive bacteria with great potential to bioremediate xenobiotics. One strain, Streptomyces sp. M7, isolated from organochlorine pesticide contaminated sediment, was selected for its capacity to grow in presence of lindane as only carbon source. This microorganism was cultured in soil extract medium added of lindane 100 μg L−1, obtaining a maximal growth of 0.065 mg mL−1, similar to the control, with a highest lindane remotion of 70.4 % at 30°C and pH 7. When different initial pesticide concentrations (100, 150, 200, and 300 μg L−1) were added in soil medium, an increment of the microbial growth was detected in all the concentrations tested. Also a diminution of the residual lindane concentration was determined in the soil samples in relation to controls without bacteria (29.1, 78.0, 38.8, and 14.4 %, respectively). Besides, it was determined the optimum Streptomyces sp. M7 inoculum when lindane 100 μg kg−1soil was added to the soil sample. The optimum inoculum was 2 g kg−1 soil for obtaining the most efficiently bioremediation process: the lindane removal in these conditions was 67.8 % at 28 days of incubation. Later it was considered necessary to know the pesticide effects on maize plants seeded in lindane-contaminated soil previously inoculated with Streptomyces sp. M7. Lindane concentrations of 100, 200, and 400 mg kg−1 soil did not affect the germination and vigor index of maize plants seeded in contaminated soils without Streptomyces sp. M7. When this microorganism was inoculated at the same conditions, a better vigor index was observed and 68 % of lindane was removed. In this connection, Streptomyces sp. M7 was grown on culture medium in presence of root exudates of maize, spiked with 1.66 mg L−1 of lindane. The highest level of pesticide removal obtained on this condition suggests that root exudates enhanced removal of lindane by the bacterium. On the other hand, little information is available on the ability of biotransformation of organochlorine pesticides by actinomycete strains. It was demonstrated that Streptomyces sp. M7 possesses the LinA enzyme that catalyzes dehydrochlorination of lindane to 1,3,4,6-tetrachloro-1,4-cyclohexadiene (1,4-TCDN) via γ-pentachlorocyclohexene (γ-PCCH). These results confirm that actinomycete strains could be considered one of the most promising bacterial groups for lindane biodegradation in contaminated environment. Particularly, Streptomyces sp. M7 could be used for this purpose.Fil: Alvarez, Analia Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Fuentes, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Benimeli, Claudia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad del Norte Santo Tomás de Aquino. Facultad de Ciencias de la Salud; ArgentinaFil: Cuozzo, Sergio Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Sáez, Juliana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; ArgentinaFil: Amoroso, Maria Julia del R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad del Norte Santo Tomás de Aquino. Facultad de Ciencias de la Salud; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentin

Does S-Metolachlor Affect the Performance of Pseudomonas sp. Strain ADP as Bioaugmentation Bacterium for Atrazine-Contaminated Soils?

Atrazine (ATZ) and S-metolachlor (S-MET) are two herbicides widely used, often as mixtures. The present work examined whether the presence of S-MET affects the ATZ-biodegradation activity of the bioaugmentation bacterium Pseudomonas sp. strain ADP in a crop soil. S-MET concentrations were selected for their relevance in worst-case scenarios of soil contamination by a commercial formulation containing both herbicides. At concentrations representative of application of high doses of the formulation (up to 50 µg g(−1) of soil, corresponding to a dose approximately 50× higher than the recommended field dose (RD)), the presence of pure S-MET significantly affected neither bacteria survival (∼10(7) initial viable cells g(−1) of soil) nor its ATZ-mineralization activity. Consistently, biodegradation experiments, in larger soil microcosms spiked with 20× or 50×RD of the double formulation and inoculated with the bacterium, revealed ATZ to be rapidly (in up to 5 days) and extensively (>96%) removed from the soil. During the 5 days, concentration of S-MET decreased moderately to about 60% of the initial, both in inoculated and non-inoculated microcosms. Concomitantly, an accumulation of the two metabolites S-MET ethanesulfonic acid and S-MET oxanilic acid was found. Despite the dissipation of almost all the ATZ from the treated soils, the respective eluates were still highly toxic to an aquatic microalgae species, being as toxic as those from the untreated soil. We suggest that this high toxicity may be due to the S-MET and/or its metabolites remaining in the soil