This award provides renewed funding for a Research Experience for Undergraduates (REU) program at the University of Maryland. The program will provide 15 students with a 12-week active learning experience each summer for five years, for a total of 75 students over the duration of the program. The students will be housed at one of the two Univ. of Maryland marine laboratories, Chesapeake Bay Laboratory or Horn Point Laboratory, and will work closely with a scientist-mentor to design, conduct and complete a summer research project. Following a 5.5-day orientation, REU students work with their scientist-mentor to write an NSF-style proposal, give a mid-summer presentation, conduct field and laboratory studies, analyze data, write a final research paper and present a talk at a final symposium. The program introduces REU students to applying the scientific method; learning field and lab methods; developing an understanding of estuarine processes; achieving an in-depth understanding of a research problem; and learning to interpret, organize and present in written and oral form the results of a research project. Students may work individually with their mentors or as part of a large, interdisciplinary research program. Recent student research topics include nutrient biogeochemistry, estuarine modeling, sedimentology, trace element chemistry, land use impacts, fisheries bioenergetics modeling, predator/prey studies, microbial ecology, genetics, environmental contamination and organism toxicity. In addition, student activities include learning about science communication, research ethics, the graduate school application process, networking and alternative careers in marine science.