Optical Society

Novel design for microfluidic sensor uses streams of unconfined water for a simpler and cheaper way to test for dangerous chemicals and bacteria

A close-up of the liquid jet sensor with the liquid jet (left) and without it (right). The jet of water is less than a millimeter in diameter.

When you shine ultraviolet light (UV) through water polluted with certain organic chemicals and bacteria, the contaminants measurably absorb the UV light and then re-emit it as visible light. Many of today’s more advanced devices for testing water are built to make use of this fluorescent property of pollutants; but the walls of the channels through which the water travels in these devices can produce background noise that makes it difficult to get a clear reading. Reported today, in The Optical Society’s (OSA) open-access journal, Optics Express, researchers in Italy have developed a pollutant detector that forgoes the channels in favor of a narrow stream of water unconfined by tubes or pipes. The naked jet of water doubles as both the sample and the collection equipment, providing a simple, cheap, and portable new tool to analyze liquids developed in the framework of the research project ACQUASENSE. Read more

Countless marine microbes called Prochlorococcus are the primary basis for most ocean food webs, yet microbiologists know very little about the diversity with this group of photosynthetic bacteria.

Prochlorococcus in freeform, an artist’s rendering of microbes in the ocean.

A new study, published in the journal Science, describes hundreds of subpopulations of these essential marine bacteria. An international team of researchers were able to identify the different subgroups through a comprehensive genomic analysis of microbes found in a milliliter of ocean water. Read more

For decades, scientists have been on a quest to find liquid water on the surface of Mars and new images from the Mars Reconnaissance Orbiter may finally provide that evidence.

This image includes an especially long example of a type of dark marking that advances down some Martian slopes in warmer months and fades away in cooler months.

Newly released images from NASA clearly show dark streaks seasonally advancing down slopes close to the Martian equator, which space agency scientists say could be due to salty water.

“The equatorial surface region of Mars has been regarded as dry, free of liquid or frozen water, but we may need to rethink that,” said Alfred McEwen of the University of Arizona in Tucson, principal investigator for the Mars Reconnaissance Orbiter (MRO) High Resolution Imaging Science Experiment (HiRISE) camera. Read more

The next time you find yourself lost in the woods with no clean drinking water, the nearest pine tree may save your life. While lake or pond water may provide some short-term relief from dehydration when in the wild, these sources of water are not always clean.

This is where the pine tree comes into play. Pouring lake water through a freshly-peeled pine tree limb can effectively remove most bacteria that may exist in the water, leaving you with a clean and fresh source of H2O. Read more

Reusing plastic water bottles helps the environment and saves money but can present a health hazard if the bottles harbor bacteria or the plastics begin to break down. Many people enjoy drinking chilled water from a bottle for its convenience, but it is important to know how to safely reuse water bottles. Read more