Marissa Bauer Wulff is a biologist with the U.S. Geological Survey’s California Water Science Center, where she researches and assists in projects relating to aquatic biology and ecology. Marissa has been involved in ecosystem modeling for the Sacramento-San Joaquin Delta as well as flow-regime and aquatic mercury studies. Marissa is currently involved in research looking at the effects of climate change on selected fish species of the San Francisco Bay-Delta.
Science and Products
Native fish population and habitat study, Santa Ana River, California
Collection of additional data on the Santa Ana Sucker (Catostomus santaanae) and the Arroyo Chub (Gila orcutti) has been identified as a needed task to support development of the upper Santa Ana River Habitat Conservation Plan (HCP; http://www.uppersarhcp.com/). The ability to monitor population abundance and understanding the habitats used by...Wulff, Marissa L.; Brown, Larry R.; May, Jason
Assessment of interim flow water-quality data of the San Joaquin River restoration program and implications for fishes, California, 2009-11
After more than 50 years of extensive water diversion for urban and agriculture use, a major settlement was reached among the U.S. Departments of the Interior and Commerce, the Natural Resources Defense Council, and the Friant Water Users Authority in an effort to restore the San Joaquin River. The settlement received Federal court approval in...Wulff, Marissa L.; Brown, Larry R.
Associations of benthic macroinvertebrate assemblages with environmental variables in the upper Clear Creek watershed, California
Benthic macroinvertebrates are integral components of stream ecosystems and are often used to assess the ecological integrity of streams. We sampled streams in the upper Clear Creek drainage in the Klamath—Siskiyou Ecoregion of northwestern California in fall 2004 (17 sites) and 2005 (original 17 plus 4 new sites) with the objectives of...Brown, Larry R.; May, Jason T.; Wulff, Marissa
Upper Clear Creek watershed aquatic chemistry and biota surveys, 2004-5, Whiskeytown National Recreation Area, Shasta County, California
The U.S. Geological Survey, in cooperation with the National Park Service and Whiskeytown National Recreation Area, performed a comprehensive aquatic biota survey of the upper Clear Creek watershed, Shasta County, California, during 2004-5. Data collected in this study can provide resource managers with information regarding aquatic resources,...Wulff, Marissa L.; May, Jason T.; Brown, Larry R.
Concentrations of mercury and other metals in black bass (Micropterus spp.) from Whiskeytown Lake, Shasta County, California, 2005
This report presents the results of a reconnaissance study conducted by the U.S. Geological Survey (USGS) to determine mercury (Hg) and other selected metal concentrations in Black bass (Micropterus spp.) from Whiskeytown Lake, Shasta County, California. Total mercury concentrations were determined by cold-vapor atomic absorption spectroscopy (...May, Jason T.; Hothem, Roger L.; Bauer, Marissa L.; Brown, Larry R.
Effects of hydrologic infrastructure on flow regimes of California's Central Valley rivers: Implications for fish populations
Alteration of natural flow regimes is generally acknowledged to have negative effects on native biota; however, methods for defining ecologically appropriate flow regimes in managed river systems are only beginning to be developed. Understanding how past and present water management has affected rivers is an important part of developing such tools...Brown, Larry R.; Bauer, Marissa L.
Cliff swallows Petrochelidon pyrrhonota as bioindicators of environmental mercury, Cache Creek Watershed, California
To evaluate mercury (Hg) and other element exposure in cliff swallows (Petrochelidon pyrrhonota), eggs were collected from 16 sites within the mining-impacted Cache Creek watershed, Colusa, Lake, and Yolo counties, California, USA, in 1997-1998. Nestlings were collected from seven sites in 1998. Geometric mean total Hg (THg) concentrations ranged...Hothem, Roger L.; Trejo, Bonnie S.; Bauer, Marissa L.; Crayon, John J.
Mercury and trace elements in crayfish from northern California
We collected two species of crayfish, Pacifastacus leniusculus and Procambarus clarkii, from Cache and Putah Creeks, California, and analyzed them for mercury and trace elements. Trace elements were higher in carcasses in 40 cases, higher in tails in 5 cases, and not different in 35 cases; no concentration exceeded levels considered harmful....Hothem, R.L.; Bergen, D.R.; Bauer, M.L.; Crayon, J.J.; Meckstroth, A.M.