This descriptive study provides a comparison of existing high school marine science curricula and instructional practices used by nine teachers across seven schools districts in Florida and their students' level of scientific literacy, as defined by the national science standards and benchmarks. To measure understandings of science concepts and Science--Technology--Society-related issues, students were assessed at the beginning and end of their course using three instruments developed by the researcher. Paired-sample "t" tests revealed a significant improvement (p less than 0.001, t = 4.42, n = 399, Cohen's d = 0.22) from 39.5% on the pre science assessment to 42.9% on the post science assessment. Students of teachers who integrated biological, chemical, geological, and physical characteristics of the oceans performed higher on the content assessment than other students. Based on a Likert scale survey, students' understandings of Science--Technology--Society-related issues did not significantly change, although post-instruction qualitative responses were reflective of the national science standards and benchmarks. Results indicate that marine science can be used as a model for teaching integrated science if curricula and instructional practices are aligned to national standards. (Contains 1 figure and 3 tables.)