Las cianobacterias planctónicas del lago tropical cárstico Lagartos de la Península de Yucatán, México. The tropical karstic lakes on the Mexican Caribbean Sea coast are numerous. However, there is an enormous gap of knowledge about their limnological conditions and micro-algae communities. In the present study, surface water samples were collected monthly from November 2007 to September 2008 to provide taxonomical composition and biovolume of planktonic cyanobacteria of the lake Lagartos from State of Quintana Roo, Mexico. Water temperature, pH, conductivity, salinity, soluble reactive phosphorus (SRP), dissolved inorganic nitrogen (DIN), and soluble reactive silica (SRSi) levels were also analyzed. A total of 22 species were identified. Chroococcales and Oscillatoriales dominated the phytoplankton assemblages during the study period. Chroococcus pulcherrimus, Coelosphaerium confertum, Cyanodyction iac, Phormidium pachydermaticum and Planktolyngbya contorta were recorded for the first time in Mexico. A surplus of DIN (mean value of 42.7µM) and low concentrations of SRP (mean value of 1.0µM) promoted the enhanced growth and bloom formation of cyanobacteria. The mean biovolume was 3.22X10 8 µm 3 /mL, and two biovolume peaks were observed; the first was dominated by Microcystis panniformis in November 2007 (7.40X10 8 µm 3 /mL), and the second was dominated by Oscillatoria princeps in April 2008 (6.55X10 8 µm 3 /mL). Water quality data, nitrates enrichment, and trophic state based on biovolume, indicated that Lagartos is a hyposaline, secondarily phosphorus-limited, and eutrophic lake, where the cyanobacteria flora was composed mainly by non-heterocystous groups. Rev. Biol. Trop. 61 (2): 971-979. Epub 2013 June 01.
Vinasses are one of the main wastes generated from the mezcal industry in Mexico. Due to their high organic matter content and low pH, vinasses have negative environmental impacts if discharged without any treatment. An alternative treatment of vinasses is their use in microbial fuel cells (MFC) for organic matter removal and electricity production. In this paper, the performance of a MFC using vinasses is analyzed. Different organic matter concentrations in terms of chemical oxygen demand (COD) were tested and compared regarding power density, internal resistance, and voltage production. The results demonstrated that the highest COD tested resulted in a poor MFC performance. When using vinasses in MFC for 10 days, COD of 6000 mg/L generated 80.64 W/m 3 and when using vinasses with a COD of 17 143 mg/L, the power density dropped to 5.13 W/m 3 . Further tests of COD performance in MFC were made with 10 640 and 6760 mg/L for 68 days. It was demonstrated that a COD of 10 604 mg/L only produced 0.61 V, while a COD of 6760 mg/L reached 0.81 V. Regarding the organic matter removal, the highest COD removed (92 %) was obtained when using vinasses with a COD of 10 604 mg/L. By operating the cell with 6000 mg/L, COD removal was 83 % and with 17 143 mg/L, 49 %. To achieve a better MFC performance, the organic matter content in the electrolyte should not exceed 6000 mg/L so that the MFC does not achieve a saturated state that hinders the oxidation mechanisms and thus electricity production and COD removal.Palabras clave: Agave, demanda química de oxígeno, remoción de materia orgánica, producción de electricidad
RESUMENLas vinazas son uno de los principales residuos generados por la industria del mezcal en México. Debido a su alto contenido de materia orgánica y bajo pH, las vinazas tienen impactos ambientales negativos si se descargan sin tratamiento alguno. Un tratamiento alternativo de las vinazas es su utilización en celdas de combustible microbianas (CCM) M. López Velarde Santos et al. 522 para la disminución de materia orgánica y la producción de electricidad. En este trabajo se analiza el rendimiento de una CCM operada con vinazas. Diferentes concentraciones de materia orgánica en términos de demanda química de oxígeno (DQO) se utilizaron y compararon con respecto a la densidad de potencia, resistencia interna y la producción de voltaje. Los resultados demostraron que la DQO más alta, dio como resultado un pobre rendimiento de la CCM. Al utilizar las vinazas en la CCM durante 10 días, una DQO de 6000 mg/L generó 80.64 W/m 3 y utilizando las vinazas con una DQO de 17 143 mg/L, la densidad de potencia se redujo a 5.13 W/m 3 . Otras pruebas de rendimiento de la DQO en la CCM se llevaron a cabo por 68 días con DQO de 10 640 y 6760 mg/L. Se demostró que una DQO de 10 604 mg/L sólo produjo 0.61 V, mientras que una DQO de 6760 mg/L alcanzó 0.81 V. En cuanto a la remoción de materia orgánica, la mayor remoción de DQO (92 %) se obtuvo utilizando vinazas en la CCM con 10 604 mg/L de DQO. Utilizando una DQO de 6000 mg/L,...
In 2010, we surveyed 42 sampling locations at 11 sites along the Mexican part of the Mesoamerican Reef System, including eight protected natural areas of the coastal state of Quintana Roo, to determine the richness of benthic-epiphytic dinoflagellates in the area. At each site, the host macroalgae of the genera Dictyota, Halimeda, Laurencia, Sargassum, and Stypopodium were manually collected. A total of 383 samples were analyzed microscopically using transmitted light, epifluorescence with calcofluor staining, and scanning electron microscopy. A total of 24 dinoflagellate species distributed among the genera Amphidinium, Bysmatrum, Coolia, Gambierdiscus, Ostreopsis, Prorocentrum, Plagiodinium, and Sinophysis were identified. Prorocentrum is the most diverse genus in the benthic-epiphytic environment with 13 species. This work also includes 15 new records of species from the Mexican Caribbean.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.