MGS Staff

A broadly trained geologist and avid naturalist, Dr. Brian Yellen is thrilled to serve as the Massachusetts State Geologist. Yellen specializes in earth surface processes, coastal processes, and hydrology. He brings varied professional experience to the Massachusetts Geological Survey, including work in the private sector groundwater cleanup industry, teaching high school physical science, and academic research. Since 2012, he has taught professional development workshops to licensed environmental consultants, teaching skills in hydrogeology and geomorphology. Research highlights from Yellen’s recent work include assessments of dam removals and sediment transport, coastal change and blue carbon, and fluvial erosion due to extreme floods. Climate change adaptation is a common theme in Yellen’s work, and reflects his past role directing a graduate fellowship program focused on developing stakeholder engagement and collaboration skills surrounding climate adaptation. Yellen received his bachelors from Brown University, a masters in education from the University of Hawaii Manoa, and his Ph.D. in geology from the University of Massachusetts Amherst. He has been a faculty member and graduate student advisor in the department of Earth, Geographic, and Climate Sciences at UMass Amherst since 2017.

Serving as State Geologist from 2002 to 2024, Dr. Stephen B. Mabee received his B.S. degree in Geology from Tufts University in 1974 and an M.S. degree in Geology from the University of Colorado in 1978. He worked for nearly 10 years in the private sector as an environmental consultant working for R.V. Lord and Associates in Boulder, Colorado and Sasaki Associates, Inc. in Watertown, MA where he was a senior associate and project manager. He worked on major design and construction projects across the U.S. He received his Ph.D. in Geology from the University of Massachusetts Amherst in 1992 with a focus on hydrogeology, geochemistry, geophysics and structural geology. He was a visiting assistant professor at Amherst College from 1992 to 1995 teaching hydrogeology and environmental geology and an introductory environmental topics course. He joined the faculty in the Department of Earth, Geographic, and Climate Sciences at the University of Massachusetts in 1995. His research interests and outreach activities include: 1) groundwater resource evaluation in bedrock; 2) application of geophysical techniques to environmental problems; 3) hydrogeological education; and, 4) water resources in ancient cultures. He was appointed State Geologist on September 1, 2002 and retired in February, 2024, but continues to serve as emeritus faculty in the Department of Geosciences.

At MGS, where I serve as the geospatial intern for Summer 2025, I have worked to increase our understanding of the environmental characteristics of various long-term forest plots on state forestland. I have also worked with Dr. Speiser to validate an automated workflow which identifies pools in Massachusetts salt marshes from satellite imagery. I completed my undergraduate education in environmental science at Middlebury College and am now completing an MS in Geographic Information Science and Technology at UMass Amherst.

Melissa received dual B.S. degrees in Environmental Science and Geology from the University of Massachusetts Amherst in 2025. She now works as a research scientist with the Massachusetts Geological Survey, assisting efforts on two projects: 1) assessing carbon stocks, health, and productivity of forest soils; and 2) monitoring salt marsh restoration efficacy and resilience.

Rising Informatics senior at Umass Amherst. Currently an intern with the Massachusetts Geological Survey mainly responsible for the redesign and migration of the MGS website. Also assists with organizing and streamlining metadata for ScholarWorks integration.

I am a postdoc researcher investigating changes in marine-sourced sediment supply and their effects on tidal marsh resilience to sea level rise using satellite observations.

William Speiser is a postdoctoral research associate at the University of Massachusetts, Amherst. His expertise is in remote sensing, data analysis, and monitoring of coastal systems. Currently, he is working on monitoring vegetation and hydrological trends in Massachusetts' salt marshes using satellite and aerial imagery data, and field data. This work focuses on finding regions in need of intervention (e.g. salt marsh hydrologic feature expansion and problematic vegetation shifts), as well as tracking the efficacy of existing restoration efforts statewide. He received his PhD in Hydrologic Sciences from the University of California, Davis, where he used remote sensing to study sediment transport, geomorphology, and water quality in nearshore, estuarine, and beach systems.