March 2011, Vol. 23, No.3

Waterline

Whales: Nature’s nitrogen pump

Whales carry nutrients, such as nitrogen, from ocean depths and feed it back to the ocean surface through their feces, functioning as an upward biological pump. This process enables more phytoplankton to grow, which leads to a greater abundance of aquatic life in ocean fisheries.

Whale biologist Joe Roman of the University of Vermont (Burlington) and professor of biological oceanography James McCarthy of Harvard University (Cambridge, Mass.) made this discovery, according to a University of Vermont news release. They considered several scenarios, estimating current whale stocks at 10%, 25%, or 50% of historic levels and found that this “whale pump” played a much larger role before commercial harvest began. But even reduced populations of whales improve the health of ocean ecosystems, the news release says. The study was published Oct. 11 in the journal PLoS ONE.   

New York plans to use ‘green’ infrastructure to reduce overflows

New York City (NYC) Mayor Michael R. Bloomberg and Environmental Protection Commissioner Cas Holloway unveiled a new plan to use “green” infrastructure to improve the quality of waterways around the city by capturing and retaining stormwater to reduce sewer overflows, according to a NYC news release.

The new plan, called the NYC Green Infrastructure Plan, has been submitted for approval to the State Department of Environmental Conservation. It would replace the existing approach for controlling sewer overflows by investing $2.9 billion in traditional infrastructure and $2.4 billion in green infrastructure. Combining traditional infrastructure with green infrastructure is expected to reduce combined sewer overflows by more than 45 million m3/yr (12 billion gal/yr), or 40%, by 2030, the news release says. The plan also is expected to reduce long-term sewer management costs by $2.4 billion during the next 20 years.

Green infrastructure plans include several types of projects. Vegetated green roofs and nonvegetated “blue” roofs will use vegetation or mechanical devices to slow stormwater runoff. Porous pavement, tree pits, and streetside swales will enable water to pool in underground holding areas until it can dissipate. Wetlands and swales for parks, along with rain barrels in residential areas, also will slow down the distribution of stormwater. The city already has more than 30 green infrastructure demonstration projects that have been built, are under construction, or are in design, the news release says.  

Using ultraviolet light to kill microbes in carpets

Adding ultraviolet light to vacuum cleaners — a technology better know for wastewater disinfection — can almost double the removal of potentially infectious microorganisms from a carpet’s surface, according to new research conducted at Ohio State University (Columbus).

A university research group evaluated the standard rotating-brush or beater-bar operation of a commercially available upright vacuum and a lamp that emits germicidal radiation. Findings suggest that incorporating this light into vacuuming might have promise in reducing allergens and pathogens from carpets, according to a university news release.

The researchers looked at tight-loop carpet; medium carpet with longer, dense loops; and loose carpet. The looser carpet found in residential homes poses the greatest health risk as a reservoir for accumulating contaminants.

On carpet surfaces, vacuuming alone reduced microbes by 78%, while ultraviolet light alone reduced microbes by 60%. The combination of the two reduced microbes by 87%. For colony-forming units of microbes, the researchers found that vacuuming alone removed 7.3 per contact plate, ultraviolet light removed 6.6 per contact plate, and together the two removed 13 per contact plate, the news release says.

More testing of the technology is needed, especially in residential areas and other environments at risk of contamination, the news release says. The research, supported through a contract with Halo Technologies Inc. (Des Plaines, Ill.), is reported in the Dec. 15 issue of the journal Environmental Science & Technology

Attempting to decode the effect of nanoparticles on biofilms

A student and assistant professor at the University of New Haven (West Haven, Conn.) are working to find out how titanium dioxide nanoparticles, used to whiten and brighten various products — such as candy, toothpaste, and paint — affect biofilms and Long Island Sound.

Chemical engineering student Nicole Reardon and assistant professor Shannon Ciston want to determine if titanium dioxide affects marine biofilms, which are an important part of the ocean environment. These biofilms transform nitrogen and carbon into substances that positively affect the food web, clean wastewater by consuming organic matter, and can clean oil and gas spills through bioremediation, according to a university news release.

For the study, Reardon and Ciston collect biofilm samples from local piers using a substrate system that Reardon designed. Reardon then stains the biofilm bacteria with fluorescent nucleic acid and, using digital image analysis, collects data on the depth and biomass of the test subjects. She also uses optical microscopy and scanning electron microscopy to identify characteristics of the biofilm structure and identify the organisms, the news release says. The samples are dosed with a composite material made of carbon nanotubes and titanium dioxide nanoparticles. Ultimately, the dosed biofilm will be compared to untreated samples to determine howthe microorganisms were affected and to look at the greater implications for Long Island Sound.

 

 

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