No Effect of Microgravity and Simulated Mars Gravity on Final Bacterial Cell Concentrations on the International Space Station: Applications to Space Bioproduction.

Microorganisms perform countless tasks on Earth and they are expected to be essential for human space exploration. Despite the interest in the responses of bacteria to space conditions, the findings on the effects of microgravity have been contradictory, while the effects of Martian gravity are nearly unknown. We performed the ESA BioRock experiment on the International Space Station to study microbe-mineral interactions in microgravity, simulated Mars gravity and simulated Earth gravity, as well as in ground gravity controls, with three bacterial species: Sphingomonas desiccabilis, Bacillus subtilis, and Cupriavidus metallidurans. To our knowledge, this was the first experiment to study simulated Martian gravity on bacteria using a space platform. Here, we tested the hypothesis that different gravity regimens can influence the final cell concentrations achieved after a multi-week period in space. Despite the different sedimentation rates predicted, we found no significant differences in final cell counts and optical densities between the three gravity regimens on the ISS. This suggests that possible gravity-related effects on bacterial growth were overcome by the end of the experiment. The results indicate that microbial-supported bioproduction and life support systems can be effectively performed in space (e.g., Mars), as on Earth.

Effect of severe hurricanes on Biorock Coral Reef Restoration Projects in Grand Turk, Turks and Caicos Islands

Artificial reefs are often discouraged in shallow waters over concerns of storm damage to structures and surrounding habitat. Biorock coral reef restoration projects were initiated in waters around 5m deep in Grand Turk, at Oasis (October 2006) and at Governor’s Beach (November 2007). Hemi-cylindrical steel modules, 6m long were used, four modules at Oasis and six at Governor’s Beach. Each project has over 1200 corals transplanted from sites with high sedimentation damage, and are regularly monitored for coral growth, mortality and fish populations. Corals show immediate growth over wires used to attach corals. Growth has been measured from photographs using a software program and is faster at Governor’s Beach. After hurricanes Hanna and Ike (September 2008) the Governor’s Beach structure was fully standing since the waves passed straight through with little damage, the Oasis structures which were tie-wired rather than welded had one module collapse (since been replaced with a new, welded structure). Hurricane Ike was the strongest hurricane on record to hit Grand Turk. Most cables were replaced following the hurricanes due to damage from debris and high wave action. The projects lost about a third of the corals due to hurricanes. Most of those lost had only been wired a few days before and had not yet attached themselves firmly. These projects have regenerated corals and fish populations in areas of barren sand or bedrock and are now attractive to snorkelers. High coral survival and low structural damage after hurricanes indicate that Biorock reef restoration can be effective in storm-impacted areas. Rev. Biol. Trop. 58 (Suppl. 3): 141-149. Epub 2010 October 01.

Con frecuencia no se favorece la creación de arrecifes artificiales en aguas someras debido a que se estima que las tormentas pueden producir daños en las estructuras y en el hábitat circundante. En las aguas de Grand Turk, a unos 5m de profundidad, se iniciaron proyectos de restauración de arrecifes coralinos en Oasis (octubre 2006) y en Governor’s Beach (noviembre 2007). Se utilizaron módulos de acero semicilíndricos, 4 en Oasis y 6 en Governor’s Beach. A cada proyecto se han trasplantado más de 1200 corales desde sitios con un elevado daño por sedimentación y se monitorean regularmente para evaluar crecimiento y mortalidad de los corales, así como la población de peces. Los corales muestran un crecimiento inmediato sobre los alambres utilizados para asegurar los corales. Este crecimiento se ha medido usando fotografías y un programa de computación y es más rápido en Governor’s Beach. Después de los huracanes Hanna e Ike (setiembre 2008), las estructuras en Governor’s Beach se mantuvieron erectas debido a que las olas pasaron a través de las mismas sin afectarlas, una de las estructuras en Oasis colapsó debido a que todas se amarraron con alambre en vez de soldarse (desde entonces se sustituyó con una nueva, soldada esta vez). El huracán Ike ha sido el más fuerte de los históricamente registrados que ha impactado Grand Turk. La mayor pare de los cables fueron reemplazados debido a daños causados por la acción de detritus y de las grandes olas. Los proyectos perdieron alrededor de un tercio de los corales debido a los huracanes. La mayoría de los corales perdidos habían sido amarrados a las estructuras unos días antes de los huracanes y consecuentemente no se habían adosado firmemente a las mismas. Estos proyectos han regenerado poblaciones de corales y peces en áreas inhóspitas de arena o roca y constituyen ahora una atracción para el buceo superficial. La alta tasa de supervivencia de corales y el bajo daño a las estructuras después de los huracanes indican que la tecnología Biorock para restauración de arrecifes coralinos es efectiva en áreas impactadas por tormentas.