A University of Florida study shows that mollusk fossils provide a reliable measure of human-driven changes in marine ecosystems and shifts in ocean biodiversity across time and space.Collecting data from the shells of dead mollusks is a low-cost, low-impact way of glimpsing how oceans looked before pollution, habitat loss, acidification and explosive algae growth threatened marine life worldwide. Mollusk fossils can inform current and future conservation and restoration efforts, said Michal Kowalewski, the Jon L. and Beverly A. Thompson Chair of Invertebrate Paleontology at the Florida Museum of Natural History on the UF campus and the study’s principal investigator.