Patrick Center for Environmental Research

The Patrick Center for Environmental Research (PCER) is an environmental research group located within the Academy of Natural Sciences of Drexel University. Formerly called the Limnology Department, PCER was founded in 1947 by Ruth Patrick, who had been working in the Diatom Herbarium at the Academy. PCER specializes in applied ecology for wetlands. It was one of the earliest U.S. environmental consulting concerns, and its presence within the Academy enabled it to become the first to employ interdisciplinary teams of scientists to study freshwater systems. PCER was also the first to regard biodiversity as a central criterion of water quality.

PCER's 1948 biological survey of the Conestoga River Basin in Pennsylvania was a milestone in environmental research. That survey led to similar surveys and studies throughout much of the United States. These early projects were joint efforts of the Limnology Department and private industry.

Over decades, the Patrick Center was reorganized into a variety of sections, based on specialty:

• Biogeochemistry
• Environmental Planning, Policy and Innovation
• Fisheries
• Macroinvertebrates
• Phycology (the former Limnology department founded by Ruth Patrick that evolved into PCER)
• Watershed Ecology
• Wetlands Research

As of 2022, the kinds of environmental assessments pioneered at the Academy are increasingly conducted by private, for-profit environmental consulting firms.