Earthwatch International Volunteer Expeditions
EARTHWATCH Institute is the nonprofit volunteer organization which pioneered matching ordinary people age 16-85 with noted university scientists worldwide to help on working field research expeditions in 49 countries and 20 U.S. states each year.
http://www earthwatch.org/
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Ecovolunteer Program

http://www ecovolunteer.org/
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One World Workforce
Hands-on volunteer sea turtle conservation trips.
http://www 1ww.org/
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