Each year workers clean five to six tons of trash off the coast of an uninhabited island in Hawaii.

Just imagine that what's still in the water.

Environmental concerns such as this one, cited by Paul H. Forestell, director of research and education at Hawaii's Pacific Whale Foundation, were the subjects at hand at Harvard this past weekend as Forestell and nearly 100 other environmental scientists met of the 12th annual interdisciplinary Earthwatch conference.

Ninety-five scientists from 15 countries convened at the four-day symposium, "Education for a Fast Changing World," which took place at the Science Center, Memorial Hall and Earthwatch's Watertown office.

The scientists and Earthwatch staff who met in the Science Center organized panel discussions to familiarize the public with six areas of their emphasis: education, biodiversity, youth and environment, cultural diversity, managing the environment and past human adaptation to environmental change.

Earthwatch, a non-profit organization began 21 years ago as a multi-disciplinary agency to fund field-based research projects.

Some funds are derived from donations, but most of the money and labor comes from Earthwatch volunteers who pay to participate in two to three week field work trips, working alongside a principal investigator.

The primary goals of the annual conference are to publicize the new research opportunities, to bring the scientists and the public together, and to raise money for future Earthwatch endeavors.

Educators shared their ideas and experiences, merging their Earthwatch training and classroom activities. Some educators, like junior high school teacher Debra Schwarzendruber of Mississippi, had simulated their research with their students.

"A lot of the land in Mississippi is being deforested around our school," Schwarzendruber said. "I could relate my research in the Acadia forest to something they [students] had been hearing about."

Baird Professor of Science Edward O. Wilson moderated a discussion on biodiversity, during which scientists told brief stories and showed slides of their research sites.

And some of the news, like Forestell's, wasn't all that good.

"There are 5.2 million kilometers of rivers in the U.S.," said. Billie Kerans, a member of the Indiana University of Pennsylvania department of biology. "Only two percent of those are healthy enough to warrant protection by the government. Of the country's large rivers, over 1,000 km long, only one, the Yellowstone River, has not been altered physically or chemically by humans."

Kerans attended the conference to present work on new approaches to measuring and protecting water resources. Many of the research projects, like Kerans's, are geared toward collecting enough concrete data to effect changes in the federal government's environment policy.

Moore Professor of Biological Anthropology Irven' DeVore moderated the panel on human adaptation to environmental change. Scientists on this panel concentrated on the use of archaeological evidence to explain the impact of the earth's climatic changes on past cultures, and to then forecast future impact.