Graduates and guests at spring commencements will hear from leaders and innovators in a variety of fields: elected and appointed public servants, an astronaut, a humanitarian, an educator, a business innovator and a winemaker.

Darrell Steinberg, California Senate President pro Tempore, will speak at the first of the spring ceremonies, the School of Law commencement, at 10:30 a.m. on Saturday, May 16, in the ARC Pavilion. He graduated from the school in 1984.

Other guest speakers include:

June 6 — Condessa Curley, a Southern California physician and founder of Project Africa Global, will speak at the School of Medicine ceremony at 10 a.m. at the Mondavi Center for the Performing Arts. Through her nonprofit organization, the UC Davis alumna provides medical and humanitarian services to African communities in need.

June 10 — Carlos Garcia, superintendent of the San Francisco United School District an educator for more than 30 years, will speak at the ceremony for the School of Education at 4 p.m. at the Mondavi Center.

June 11 — Elizabeth Vianna, winemaker with Chimney Rock Winery in Napa, will speak at the Graduate Studies ceremony at 4 p.m. in the ARC Pavilion. She earned a master’s degree in food science from UC Davis in 2000.

June 12 — Steve Robinson, astronaut and College of Engineering alumnus, will speak to graduates of his college at 3 p.m. in the ARC Pavilion.

June 13 — Pam Marrone, founder and chief executive officer of Marrone Bio Innovations, will address graduates of the Graduate School of Management at 10 a.m. at the Mondavi Center. Formerly a leader at AgraQuest, she serves on the UC President’s Board of Science and Innovation and the dean’s advisory council for the management school.

June 13 — Mary Nichols, chair of the California Air Resources Board, will speak at both ceremonies of the College of Agricultural and Environmental Sciences at 9 a.m. and 2 p.m. in the ARC Pavilion. She was one of the state’s first environmental lawyers.

The School of Law will award 16 Master of Laws and 192 Juris Doctor degrees at its ceremony.

Other ceremonies will be held as follows:

June 12 — College of Biological Sciences at 10 a.m. in the ARC Pavilion.

June 12 — School of Veterinary Medicine at 10:30 a.m. at the Mondavi Center.

June 14 — College of Letters and Science at 9 a.m. and 2 p.m. in the ARC Pavilion.

UC Davis will offer live and on-demand webcasts of each of the commencements at commencementvideo.ucdavis.edu.