June 2011, Vol. 23, No.6

Waterline

Ancient corals may reveal history of environmental change

Scientists have determined the age of some truly ancient sea animals thriving at depths of 300 m (984 ft) and greater. The Gulf of Mexico is home for 2000-year-old deep-sea black corals.

Even though the corals live deep under the ocean’s surface, scientists say they are sensitive not only to ocean floor conditions but also to surface ocean conditions. This is because they feed on organic matter that sinks to the ocean floor, according to a U.S. Geological Survey (USGS) news release.

Dating the age of the corals, as USGS did in this recent study, is a step toward using them as natural archives of environmental change, the news release says.

USGS scientists and their colleagues are measuring trace metals and stable isotopes in the black coral skeleton that are related to nutrient supply in surface waters. These concentrations may reflect the amount of runoff from nearby land surfaces. Understanding how these chemical constituents vary over time enables scientists to reconstruct a record of environmental changes, such as changes in land-based sources of nutrients and natural variations in climate.

View an abstract of the research report at www.int-res.com/abstracts/meps/v423/p101-115.

 

USGS identifies beach erosion along East Coast

Scientists have quantified beach erosion in the New England and Mid-Atlantic regions during the past 150 years. An assessment of coastal change found that 68% of beaches in the region are eroding, according to the U.S. Geological Survey (USGS).

After studying more than 1046 km (650 mi) of coastline, scientists found that the average rate of coastal change was negative 0.5 m (1.6 ft) per year, with the most extreme erosion exceeding 18 m (60 ft) per year, according to a USGS news release.

Researchers used historical data sources, such as maps and photographs, as well as light-detection and ranging technology to measure shoreline change at more than 21,000 locations. The results provide a baseline for coastal change information for various coastal management solutions, the news release says.

The report, National Assessment of Shoreline Change: Historical Shoreline Change along the New England and Mid-Atlantic Coasts, is the fifth in a series produced as part of the USGS’s National Assessment of Shoreline Change project.

 

2011 Stockholm Water Prize winner shows how humans affect lake ecosystems

Stephen R. Carpenter has been named the 2011 Stockholm Water Prize laureate. Carpenter, a professor of zoology and limnology at the University of Wisconsin–Madison, received the award in recognition of his contributions to understanding how humans affect lakes through nutrient loading, fishing, and introduction of exotic species, according to a Stockholm International Water Institute (Sweden) news release. He reframed understandings of freshwater environments and human effects on lake ecosystems by combining theoretical models and large-scale lake experiments.

Carpenter’s research on trophic cascades in lakes, which describes how effects on any one species cascade up or down the food chain, has provided a framework for management of freshwater resources. Carpenter’s research also has proved to be applicable to other ecosystems, the news release says.

 

Hands-free faucets harbor harmful bacteria

“Out with the old, in with the new” may not be the best advice when talking about faucets in hospitals. According to a study at The Johns Hopkins Hospital (Baltimore), hands-free faucets may be bacteria-laden.

The hospital’s study shows that faucets in the hospital that are equipped with electronic-eye sensors are more likely to be contaminated with a common and hazardous bacteria, Legionella, than old-style fixtures with separate handles for hot and cold water, a Johns Hopkins Medicine news release says.

Even though the hospital treats water supplied from public utilities with chlorine dioxide or other methods to keep Legionella levels low, the disinfection did not work well on the complex valve components of newer faucets. Researchers suspect that the valves offer additional surfaces for bacteria to become trapped and grow, the news release says.

Although the high-tech faucets cut daily water consumption by more than half, Johns Hopkins researchers identified Legionella growing in 50% of cultured water samples from 20 electronic-eye faucets in or near patient rooms on three different inpatient units. On the other hand, only 15% of water cultures taken from 20 traditional, manual faucets in the same patient-care areas tested positive for the bacteria. Weekly water culture results also showed half the amount of bacterial growth of any kind in the manual faucets than in the electronic models.

As a result of the study, all 20 newer faucets were removed and replaced with manual faucets, and 100 similar electronic faucets are being replaced. Manual faucets are being included in the new clinical buildings currently under construction at the Johns Hopkins’ East Baltimore campus, the news release says.

Researchers plan to work with faucet manufacturers to create components that can be more easily cleaned while saving water.

 

©2011 Water Environment Federation. All rights reserved.