In 2004, Jens Mühle, an atmospheric chemist at Scripps Institution of Oceanography, detected an unknown compound while collecting air samples with a newly developed measurement instrument.
The compound was identified as sulfuryl fluoride (SO2F2), a gas used in the termite fumigation of buildings. Intrigued, Mühle and his team expanded their analysis to air samples collected around the world as well as to historic air samples archived in metal cylinders.
The findings were startling: SO2F2 remains in the atmosphere about 36 years, which is six to 10 times longer than previously thought.
Widespread use of SO2F2 began in the 1990s to replace the use of methyl bromide, known to deplete ozone. Currently, SO2F2 is regulated as a toxic substance but not regulated as a greenhouse gas. That may change. This first-of-its-kind study is reported in the "Journal of Geophysical Research."
Cockroaches in space
Applying the maxim "students learn best by doing," 22 UCSD freshmen engineering students designed and built payload boxes hung from a high-altitude balloon recently launched in the desert and sent aloft 85,000 feet into near space. The payloads included programmable digital cameras to take images from space, atmosphere monitoring sensors for future investigation of weather patterns and air pollution control, and data collection to evaluate the balloon-satellite's solar cell efficiency.
But the payload generating the most interest was a group of cockroaches, housed in a variety of capsules to experience a range of different extreme environments, including cold temperatures (-40 degrees F), minimal atmosphere and high solar radiation. The cockroaches being cockroaches, they all survived the trip.
The first-time UCSD balloon-satellite project was part of an Introduction to Aerospace Engineering class taught in the Jacobs School of Engineering and sponsored by NASA's California Space Grant Consortium, whose purpose is to promote aerospace engineering education as well as the development of the STEM (Science, Technology, Engineering, and Math) work force of the future.
Workings of plant biological clock revealed
UCSD biologists have identified a key protein that links the morning and evening components of the daily biological clock of plants. Scientists previously had identified two primary feedback loops in the plant daily clock - one that detects the onset of light in the morning and another that tracks when light fades in the evening - but it took more than a decade to identify what linked them.
Evidence increasingly points to an internal clock as a critical component of plant growth and the timing of flowering. This discovery solves a longstanding puzzle about the underlying biochemical mechanisms that control plant clocks and could provide a new way to increase the growth and yield of agricultural crops. The study appears in the journal "Science."