Intercontinental dust influences California rain and snow

By Lynne Friedmann

Wnds can carry dust-laden aerosols at altitudes above 16,400 feet from continent to continent. Now a study has shown that airborne dust and microorganisms from as far away as the Sahara desert can enhance precipitation in the Sierra Nevada mountains of California.

Dust can act as ice nuclei within clouds initiating the freezing of water vapor and water droplets at warmer temperatures than would naturally occur in the absence of these particles. This then falls as rain, snow or hail.

In a study led by UC San Diego and NOAA (National Oceanic and Atmospheric Administration) airborne aerosol time-of-flight mass spectrometers (ATOFMS) tracked the transport of dusty aerosols through the atmosphere from continent to continent. And other specialized detectors revealed dust ice nuclei feeding clouds and their presence in the collected residue of ice crystals.

The data could help western states better understand the future of their water supply as climate change influences how much and how often dust travels around the world and alters precipitation.

The study appears in the journal


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New marker for river blindness infection

Scientists at The Scripps Research Institute (TSRI) have found a telltale molecular marker for


(also known as “river blindness”), a parasitic infection that affects tens of millions of people living in tropical regions. The newly discovered biomarker, secreted by disease-causing worms, is detectable in patients’ urine and could form the basis of a portable, field-ready test.

There has long been a need for an inexpensive, non-invasive test that can discriminate between active and non-active river blindness infections during treatment campaigns. Current diagnostic methods include the painful cutting of skin snips from patients that can produce unreliable false-positive results.

The newly discovered biomarker shows up four to six times higher in urine samples from patients with active infection versus samples from those with non-active infections in which the biomarker level is near zero. This raises hope that a simply urine dipstick diagnostic test might be developed.

The findings appear in the

Proceedings of the National Academy of Sciences

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Fluorescent light signals coral health

Coral reefs provide the world with rich, productive ecosystems and photogenic undersea settings. In addition, they also contribute an economic boost valued at hundreds of billions of dollars.

But their global decline in recent years has lent urgency to the search for new ways to evaluate their health.

Scientists at Scripps Institution of Oceanography at UCSD report that fluorescence, the dazzling but poorly understood light produced by corals, can be an effective tool for gauging reef health.

In the study, a common Indo-Pacific reef-building branching coral, known to be susceptible to temperature stress, was exposed to varying levels of water temperature. The coral displayed a rapid decline in fluorescence level at both cold and heat stress. Cold- treated corals fared better and if able to adapt to the new conditions then fluorescence returned to normal levels. Heat-treated corals, on the other hand, tended to eventually “bleach,” a condition in which they lose tiny symbiotic algae that are critical for coral suvival.

This is the first study to measure coral fluorescence before, during, and after stress and provides a new, non-invasive method for testing coral health in the field. Heretofore, determining coral health involved removing reef samples for molecular analyses.

The findings are described in

Scientific Reports

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Lynne Friedmann is a science writer based in Solana Beach.