How does your green roof garden grow?

UNIVERSITY PARK, PA -- Growing plants on rooftops is an old concept that has evolved from simple sod roofing to roof gardens and new, lightweight "extensive green roofs". Modern green roofs have environmental and social benefits; they can reduce stormwater runoff, improve air quality, mitigate urban heat, reduce the demand for air conditioning and greenhouse gas emissions, and provide habitat for birds and wildlife. Long-used in urban planning in Europe, green roofs are becoming more popular in North America, and new research designed to promote the integration of green roofs into current and future buildings is burgeoning. Researchers from the Department of Horticulture at The Pennsylvania State University published a study in HortTechnology that evaluated the influence of substrate type and depth on establishment of five common green roof plants.

Plants suitable for extensive green roofs must tolerate extreme rooftop conditions, and the substrates in which they grow must meet both horticultural and structural requirements. Deeper substrates may retain more water for plants during dry periods, but they also weigh more, especially when near saturation. The study by Christine E. Thuring, Robert D. Berghage, and David J. Beattie was designed to evaluate the effects of substrate type and depth on the establishment and early growth of five plants popular in North American green roof designs.

New technology to speed cleanup of nuclear-contaminated sites

CORVALLIS, Ore. – Members of the engineering faculty at Oregon State University have invented a new type of radiation detection and measurement device that will be particularly useful for cleanup of sites with radioactive contamination, making the process faster, more accurate and less expensive.
A patent has been granted on this new type of radiation spectrometer, and the first production of devices will begin soon. The advance has also led to creation of a Corvallis-based spinoff company, Avicenna Instruments, based on the OSU research. The market for these instruments may ultimately be global, and thousands of them could be built, researchers say.
Hundreds of millions of dollars are spent on cleanup of some major sites contaminated by radioactivity, primarily from the historic production of nuclear weapons during and after World War II. These include the Hanford site in Washington, Savannah River site in South Carolina, and Oak Ridge National Laboratory in Tennessee.

Broken glass yields clues to climate change

A study appearing this week in Proceedings of the National Academy of Sciences finds that microscopic particles of dust, emitted into the atmosphere when dirt breaks apart, follow similar fragment patterns to broken glass and other brittle objects. The research, by National Center for Atmospheric Research (NCAR) scientist Jasper Kok, suggests there are several times more dust particles in the atmosphere than previously thought, since shattered dirt appears to produce an unexpectedly high number of large dust fragments.
The finding has implications for understanding future climate change because dust plays a significant role in controlling the amount of solar energy in the atmosphere. Depending on their size and other characteristics, some dust particles reflect solar energy and cool the planet, while others trap energy as heat.

Growing hypoxic zones reduce habitat for billfish and tuna

Billfish and tuna, important commercial and recreational fish species, may be more vulnerable to fishing pressure because of shrinking habitat, according to a new study published by scientists from NOAA, The Billfish Foundation, and University of Miami Rosenstiel School of Marine and Atmospheric Science.
An expanding zone of low oxygen, known as a hypoxic zone, in the Atlantic Ocean is encroaching upon these species' preferred oxygen-abundant habitat, forcing them into shallower waters where they are more likely to be caught.
During the study, published recently in the journal Fisheries Oceanography, scientists tagged 79 sailfish and blue marlin with satellite tracking devices in the western North Atlantic, off south Florida and the Caribbean; and eastern tropical Atlantic, off the coast of West Africa. The pop off archival satellite tags monitored horizontal and vertical movement patterns. Researchers confirmed that billfish prefer oxygen rich waters closer to the surface and will actively avoid waters low in oxygen.

The ethics of biofuels

In the world-wide race to develop energy sources that are seen as "green" because they are renewable and less greenhouse gas-intensive, sometimes the most basic questions remain unanswered.
In a paper released today by the School of Public Policy at the University of Calgary, authors Michal Moore, Senior Fellow, and Sarah M. Jordaan at Harvard University in the Department of Earth and Planetary Sciences, look at the basic question of whether these energy sources are ethical.
In addition to arguing that the greenhouse gas benefits of biofuel are overstated by many policymakers, the authors argue that there are four questions that need to be considered before encouraging and supporting the production of more biofuel.

Conditioning reefs for the future

In a world first, a new 'state of the art' climate change experimental facility has been completed at the University of Queensland's Heron Island Research Station.
The Climate Change Mesocosm (CCM) project led by Associate Professor Sophie Dove and Dr. David Kline from the Global Change Institute's Coral Reef Ecosystems Laboratory is one of the largest and most accurately controlled ocean acidification and warming experimental systems in the world and simulates ocean temperatures and acidification levels predicted to occur on coral reefs in the next 50 to 100 years.
Able to regulate both temperature and CO₂ levels prescribed by the 2100 IPCC scenarios in a highly controlled environment, the CCM system allows studies of climate change from the molecular to the ecosystem level.