Science Diary: Water - Moon: The Pulse of the Planet daily radio program offers free legal online mp3 downloads, exploring the world of sound in nature, culture and science, with audio adventures, world music, extraordinary sound portraits, science diaries, and nature ring-tones; an amazing sonic experience.

Airdate: Sep 02, 2008
Scientist: Adina Paytan

Science Diary: Water - Moon

Science Diary: Water - Moon
You may want to think twice before taking a dip in the ocean during a full moon.

music; ambience ocean surf

"There is higher bacteria in the coastal water during new moon and full moon."

The next time the moon is full, you might want to think twice about going swimming in the ocean! Welcome to Pulse of the Planet's Science Diaries, a glimpse of the world of science from the inside. Dr. Adina Paytan is an oceanographer at the University of California, Santa Cruz; she's discovered that coastal ocean water bacteria are more likely to reach unsafe levels both when the moon is full and during a new moon. Ocean levels rise and fall with the moon's gravitational pull. During a new or full moon, the sun lines up with the moon and earth, adding to that pull, and intensifying tidal forces.

"There's a couple of reasons why the tide could cause higher abundance of bacteria. If they are associated with groundwater, where there's very low tide, the ocean water is further away, so there is more height difference between the groundwater and the ocean water, and more water gets out of the groundwater and into the beach. Another reason is because at high tide and low tide, larger areas of the beach are covered by water and then drained, and this can release bacteria that are absorbed on the sand or it might not even be related directly, but rather that the inundation of the beach or the covering of the beach and drying of the beach can bring some other component that makes the bacteria more happy, and, therefore, they survive longer.

We'll hear more about tracking coastal water pollution in future programs. Third to sixth graders can challenge Adina Paytanand other scientistsin our latest project. Check out

Pulse of the Planet's Science Diaries are made possible by the National Science Foundation.