By CORNELIA DEAN

CORVALLIS, Oregon - As a young geophysicist in the 1980s, Rob Holman attended a conference in San Francisco that included a field trip to a beach. Dr.Holman, who grew up inland, in Ottawa, stared at the ocean, assessing the strengths and vectors of the waves and currents. But when he looked around, everyone else was studying the sand.

He realized, he recalled, that“sand is not the same everywhere.” So he started collecting it.“I collected a few samples and put them in jars,”he said.“Then I had so many I built a rack. Then I built three more racks. Then I built four more.”

Today Dr.Holman is best known as a coastal oceanographer at Oregon State University whose computerized photography system, called Argus, has given researchers new ways to observe and measure beaches. But he still collects sand, which he displays on shelves in the corridor outside his office. By now he has almost a thousand samples. They come from his travels and from geologists and amateurs all over the world (including this reporter) who send him grainy shipments in envelopes, plastic bags, paper towels and other wrappings. Each offering is dried and transferred to glass laboratory jars a few centimeters high, which Dr.Holman labels by latitude and longitude of their site, as best he can determine them from the sometimes sketchy information his contributors provide.

The collection includes sand from all continents, including Antarctica.

Geology students at the university study his collection, and they can learn a lot from it.“This row is a north to south transect along the East Coast,”he said one day recently, pointing to tubes containing samples collected at American sites from Cape Cod to Key West.“It just gets lighter and finer.”That is because most of the time sand is not stationary on the beach.

By the time a grain of sand washes up on a beach in Florida, it has been battered by waves for a long time.“The physical action of being continually beaten causes the grains to break down, the angular corners to break off,”he said.“They become more rounded.”

And relatively dense mineral grains, like garnet, have settled out. The result is a row of samples shifting from the relatively dark, coarse grains of the Northeast to the fine white beach sand of the Southeast.

“There are a number of characteristics you can look at? the nature of the sand and the shape, where would the minerals come from, different transport and aging,”he said.“Those all affect the sand you see on the beach.”

Dr.Holman developed the Argus system during research he began about 20 years ago at the Army Corps of Engineers research pier on the coast at Duck, North Carolina. Today, there are Argus installations at Duck and in Oregon, California, Hawaii, England, the Netherlands, Australia, New Zealand, Spain, Italy and Brazil.

Researchers assigned to the Duck pier send instruments into the surf to make precise measurements of the underwater topography in the surf zone, particularly the formation and movement of sandbars. Understanding these sandbars is critical to the study of beach erosion and climaterelated sea level rise, but the surf zone is a notoriously hostile research environment. As a practical matter, the measurements made routinely at Duck are unobtainable almost anywhere else .

Dr.Holman used the Duck instrument data and time-lapse film from a camera he mounted on a tower at the Corps installation to figure out how to correlate photographic information to changes in the topography under the surf.

The results were surprising. For one thing, sandbars were not moving in simple patterns, as many coastal scientists had thought they did. “The biggest thing we learned is how much more complicated it is than we thought it was,”he said.

Using Argus data, scientists can watch, almost in real time, as sandbars appear, disappear, curve, drift, breach and otherwise act up under the camouflage of breaking waves. The system can even be used to spot rip currents in real time.

S.Jeffress Williams, a coastal geologist with the United States Geological Survey, called the system“a critical piece of new technology.”

“The Argus system allows us to quantify and document visually the changes that take place along the coast on a variety of different time frames,”he said.

While it is true that all beaches“live by the same rules”in that the movement of wind, water, waves and sand is always a matter of F = ma (force equals mass times acceleration), beaches behave differently.“We hope to figure that out,”Dr.Holman said.

Meanwhile, sand keeps piling up.