Laboratory & Field Staff

Students Supported by MPSL-MLML since 1992

MLML Theses supported by MPSL


Marine Pollution Studies Laboratory-Department of Fish and Game
7544 Sandholdt Road
Moss Landing, CA 95039
Phone: 831-771-xxxx, where xxxx is the 4-digit extension you see listed
Email:, where #### is the email name you see listed
Fax: 831-633-0805


Laboratory & Field Staff

Name      Title Phone Number Email
Wesley Heim Director

Wes directs the researchers and oversees the management and funding of research projects at MPSL-DFG. He graduated from Humboldt State University in 1997 with a B.S. in oceanography and minor in chemistry. Wes earned his M.S. in marine science from Moss Landing Marine Laboratories in 2003. His research focuses on the biogeochemistry of mercury. Wes provides expertise at MPSL-DFG in study design, analytical chemistry, and general project development, implementation, and management.

Autumn Bonnema Program Manager 4175 bonnema

Autumn is the Program Manager and QA Officer for MPSL-DFG. She started her career here in 1996 as a part time laboratory technician while also a graduate student at MLML under Dr. Michael Foster. After she obtained her Master’s Degree in 1999, she was the Lab Manager for a number of years handling the day to day tasks of sample preparation. More recently she has been integrally involved in the Bioaccumulation Oversight Group (BOG) and the Lakes, Coastal and Rivers monitoring they conducted. Prior to MLML, Autumn obtained her undergraduate degree from Long Island University, Southampton College. Autumn specializes in generating QAPPs, project management and trace clean laboratory preparation.

Mark Stephenson
Director Emeritus, Special Project Director

Mark Stephenson began the Marine Pollution Studies Lab in conjunction with the Department of Fish and Game in the 1970s with his work on the California State Mussel Watch Program. Since then Mark has expanded the group to become what it is today. Mark obtained a BS from UC Davis, and continued his studies at MLML, earning his MS in Marine Science. Mark continued to work with the Mussel Watch Program, but also became involved in other large projects such as CALFED and SWAMP. After semi-retiring in early 2012, Mark decided to continue working with MPSL as Special Projects Director. His expertise in field and laboratory research continues to be integral to the mission of MPSL.

Gary Ichikawa
Environmental Scientist, DFG 4162 gichikawa

Gary is the DFG Program Manager at MLML. He has over 30 years experience with all types of field collections including trace level water collections, sediments, mussels and fish. Gary earned his bachelor’s degree from UC Berkeley in 1974, and was a graduate student at MLML prior to joining DFG.

Jon Goetzl
Environmental Scientist, DFG

Jon is the Trace Metals Analyst at MPSL. He received an Aquatic Biology degree from St Cloud University in Minnesota in 1979 and did graduate work at the Moss Landing Marine Lab in the early 1980s. He gained employment with the Department of Fish and Game conducting Bioassays and collecting field samples at the Granite Canyon Lab in 1980. In 1985 he started working as an Environmental Scientist for the Department of Fish and Game’s Mussel Watch Program at Moss Landing Marine Lab. Subsequently he has worked with State and Regional Water Boards on numerous water quality projects. Jon Specializes in ICP-MS analysis of tissue, sediments, and waters, but also works with the field collection team collecting samples throughout the state.

Amy Byington Analyst/Research Technician

Amy is the senior mercury and methylmercury analyst at MPSL-DFG and has been with MPSL since July 1998. Amy received her Masters Degree in 2007 from San Jose State University through Moss Landing Marine Labs. She worked with Dr. Kenneth Coale, MPSL-DFG, and Dr Gary Gill to study the Photo-degradation of Methylmercury in the Sacramento - San Joaquin Delta Estuary. Before MLML, Amy attended Texas A & M University at Galveston for her undergraduate degree in Marine Science where she worked under Dr Gary Gill at the Laboratory for Oceanographic and Environmental Research.

Billy Jakl Senior Research Technician

Billy is the Senior Research Technician for MPSL-DFG. He is responsible for managing field personal and field collection for state-wide and regional contracts. He also helps with field collection for SWAMP (Surface Water Ambient Monitoring Project) Biological Assessment, Perennial Stream Assessment (PSA), Reference Condition Management Plan (RCMP), Chemistry, and California Rapid Assessment Method (CRAM). Billy specializes in Global Information Systems/Global Positioning Systems (GIS/GPS). He received his Bachelor’s of Science in 2002 with a focus on Earth Systems Science and Policy from CSU Monterey Bay. He worked with Dr. Rikk Kvitek and studied the relationship of rockfish (Sebastes) catch per unit effort (CPUE) to marine habitat loss and kelp forest decline.

Stephen Martenuk Clean Lab Manager 4158 smartenuk

Stephen is the Clean Lab Manager for MPSL-DFG. He is responsible for overseeing the operation of the positive–pressure clean room used for processing analytical samples for various projects. The Clean Lab prepares sampling equipment and processes sediment, tissue, and water samples for trace element and mercury analysis. When possible he also helps with field collections for SWAMP (Surface Water Ambient Monitoring Project), CRAM (California Rapid Assessment Method), and any scientific diving projects (AAUS). Stephen received his Bachelor’s of Science in Marine Biology and Ecology & Evolution form the University of California, Santa Cruz in 2005 focusing on intertidal biodiversity and species interactions. Stephen specializes in microwave assisted acid digestion of sediment and tissue samples for trace element analysis on ICP-MS.

Jessica Masek Analyst/Project Assistant

Jessica became part of the MPSL team in April 2011 as a total and methylmercury analyst.  Jessica obtained her Bachelor of Science degree from Cal State Monterey Bay with a concentration in Watershed Science under Dr. Fred Watson of the Central Coast Watershed Institute.  Jessica’s expertise is in the analysis of methylmercury waters and sediments, as well as the analysis of total mercury tissues and sediments.

Sean Mundell Project Assistant

Sean is the field manager for the SWAMP (Surface Water Ambient Monitoring Project) Biological Assessment, Chemistry and CRAM (California Rapid Assessment Method) collection projects. He is currently working with the State Water Resource Control Board for the Perennial Stream Assessment (PSA) and the Reference Condition Management Plan (RCMP). Sean is also is working with numerous Regional Water Control Boards for their various sample collections. Recently Sean is involved with a Depressional Wetlands Group that is starting in Southern California in hopes to make it a statewide project. Sean is also active with data base entry for the SWAMP data base. Sean received a BS in Environmental Science and Ecology in 1997 at Sierra Nevada College in Incline Village, NV.

John Negrey Research Technician 4164

John is involved in various research projects at the lab, providing support with field sampling, data analysis, and project management. John joined the MPSL group in 1999, after graduating from the University of California, Santa Cruz with a B.A. in Marine Biology. He is currently in the process of completing his M.S. in Marine Science from Moss Landing Marine Laboratories. His research interests include the cycling and bioaccumulation of mercury and its effect on the physiology of organisms in marine and freshwater environments. John specializes in field collections and instrumentation, data management, and report writing.

Adam Newman Research Technician 4167 anewman

Adam is a Research Technician with MPSL. He began working in 2004 after graduating with a BS from CSUMB in Earth, Systems, Science and Policy. He initially analyzed methylmercury in sediment and waters as well as total mercury in sediments and tissues. Since then he has added total mercury in waters to his repertoire and has been involved with the field collection of samples in various ecosystems. Adam also took a brief hiatus from MPSL to expand his analytical tools into the detection of toxic organisms in both fresh and saltwater environments through the use of molecular probe technology. Adam’s expertise is in the analysis of organic and inorganic forms of mercury in tissues, sediments and waters.

Witold Piekarski Fisheries Biologist, DFG

Witold received his Technical/Building credentials from Technical School of Building Engineering in Gdansk, Poland in 1978. In 1989, 8 years after moving to USA, he earned a BS in Marine Biology from University of California in Santa Cruz (under the critical eye of Dr. John Pearse). He came to MLML in 2004 as a part time lab technician/field crew member. In the last 7 years, Witold has been the lead person in numerous mercury/methyl mercury related State Wide projects.

Dylan Service Research Technician

Dylan is a marine research technician for MPSL-DFG. During his twelve years with MPSL-DFG he has maintained our fleet of small boats and numerous other field collection devices. His extensive knowledge of fish collection has been a tremendous asset to tissue collection projects. He currently manages the field collection for the Bioaccumulation Oversight Group (BOG). He also assists in the collection of SWAMP (Surface Water Ambient Monitoring Project) Water/Sediment Chemistry and Biological Assessments.


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Students Supported by MPSL-MLML since 1992

MLML Students

Mark Stephenson Lara Ferry Theresa Friend Kelsey James
Mark Yarbrough Stephen Trumble Amy Byington Holly Lopez
Craig Hunter Michelle Lander Tam Voss Jeremiah Bower
Sarah Tanner Brynie Kaplan John Negrey Brynn Hooton
Susan Coale Nicolas Ladizinsky Colleen Perez Heather Hawk
Jon Goetzl Ross Clark Bill Watson Jenny Kemper
Gary Ichikawa George Leonard Brent Hughes Kelley Andrews
Bruce Welden Stewart Lamerdin Elizabeth Keddy Gabriela Navas
Bernadette Ramer Cassandra Lamerdin Laurie McConnico April Woods
Alan Fukuyama Brenda Konar Tom Wadsworth  
Farron Wallace Michele Jacobi Allison Myers  
Don Smith Doreen Moser Jon Walsh  
Debbie Schloffman Diana Steller Nisse Goldberg  
Jill Schoenherr James Downing Susan Von Thun  
Linda Martin Eli Landrau John Haskins  
Ellen Faurot Mark Pranger Lisa Barrios  
Carolyn Green Autumn Bonnema Berkeley Kaufman  
Penn Wen Alex Culley Elizabeth Sassone  
Mike Gordon Clare Dominik Tom Kimball  
Chris Troll Jim McCarthy Rhea Sanders  
Rusty Fairey Jodi Brewster Rosemary Romero  
Hunter Lenihan Wes Heim Amanda Gerke  
Debbie Wyatt Luke Beatman Gabriela Vega  


UCSC Students

May Nguyen Alona Kvitky Roselea Bond  
Jen Massey Brian Karas Aaron Felt  
Brooke Cleveland Jason Whitney Jenny Tricky  
Forrest Evans Stephen Martenuk Lana Kroll  
Jamie Wine Christy Barril Brian Freuh  


CSUMB Students

Billy Jakl Jessica Masek Adam Newman  
Chris Jett Charles Hanley III    
Amyah Gunn Kyle Skaff    
Leah Fulton Erik Adams    


High School Students

Dominic Horath Roman Marin III Tyler Coale  
Andrew Clouse LA Solano    
Heather Ichikawa Chandler Ichikawa    
Sean Goetzl Michael Radojevic    


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MLML Theses supported by MPSL

Heim, Wes
Methyl and total mercury in surficial sediments of the San Francisco Bay-Delta.

Brookens, Tiffini
Trace element concentrations in the Pacific harbor seal, Phoca vitulina richardii, in central and northern California.

Byington, Amy
Photo-degradation of Methyl Mercury in the Sacramento-San Joaquin Delta Estuary.

Kimball, Thomas
Mercury methylation in sediments from Coastal and Sierra watersheds: implications for methyl mercury mitigation in the San Francisco Bay-Delta Complex.

Sanders, Rhea
A 300-year geochronological assessment of atmospheric mercury deposition in California: implications for pre-anthropogenic biotic exposure.

Gehringer , Daphne
Molecular, histological, and behavioral differences in largemouth bass (Micropterus salmades) and topsmelt (Altherinops affinis) exposed to methyl mercury.

Sassone, Elizabeth
Monomethylmercury Loading Studies in Delta Wetlands - Twitchell Island.

Sankaran, Sonya
Effects of tissue nitrogen and eutrophication on trace metal uptake and trophic transfer by Ulva spp.


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