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Publications

For more than a century, USGS scientists have conducted research in California’s Bay-Delta region. Informing natural-resource management decisions on the region’s issues, this research has been published in thousands of documents, some highlighted below.

Filter Total Items: 308

Trajectory of early tidal marsh restoration: elevation, sedimentation and colonization of breached salt ponds in the northern San Francisco Bay

Tidal marsh restoration projects that cover large areas are critical for maintaining target species, yet few large sites have been studied and their restoration trajectories remain uncertain. A tidal marsh restoration project in the northern San Francisco Bay consisting of three breached salt ponds (≥300 ha each; 1175 ha total) is one of the largest on the west coast of North America. These diked
Authors
L. Arriana Brand, Lacy M. Smith, John Y. Takekawa, Nicole D. Athearn, Karen Taylor, Gregory Shellenbarger, David H. Schoellhamer, Renee Spenst

Mercury exposure may suppress baseline corticosterone levels in juvenile birds

Mercury exposure has been associated with a wide variety of negative reproductive responses in birds, however few studies have examined the potential for chick impairment via the hypothalamic-pituitary-adrenal (HPA) axis. The HPA axis regulates corticosterone levels during periods of stress. We examined the relationship between baseline fecal corticosterone metabolite concentrations and mercury co
Authors
Garth Herring, Joshua T. Ackerman, Mark P. Herzog

Downscaling future climate projections to the watershed scale: A north San Francisco Bay estuary case study

We modeled the hydrology of basins draining into the northern portion of the San Francisco Bay Estuary (North San Pablo Bay) using a regional water balance model (Basin Characterization Model; BCM) to estimate potential effects of climate change at the watershed scale. The BCM calculates water balance components, including runoff, recharge, evapotranspiration, soil moisture, and stream flow, based
Authors
Elisabeth Micheli, Lorraine Flint, Alan Flint, Stuart Weiss, Morgan Kennedy

Conceptual model of sedimentation in the Sacramento-San Joaquin River Delta

Sedimentation in the Sacramento–San Joaquin River Delta builds the Delta landscape, creates benthic and pelagic habitat, and transports sediment-associated contaminants. Here we present a conceptual model of sedimentation that includes submodels for river supply from the watershed to the Delta, regional transport within the Delta and seaward exchange, and local sedimentation in open water and mars
Authors
David H. Schoellhamer, Scott A. Wright, Judith Z. Drexler

A perspective on modern pesticides, pelagic fish declines, and unknown ecological resilience in highly managed ecosystems

Pesticides applied on land are commonly transported by runoff or spray drift to aquatic ecosystems, where they are potentially toxic to fishes and other nontarget organisms. Pesticides add to and interact with other stressors of ecosystem processes, including surface-water diversions, losses of spawning and rearing habitats, nonnative species, and harmful algal blooms. Assessing the cumulative eff
Authors
Nathaniel L. Scholz, Erica Fleishman, Larry Brown, Inge Werner, Michael L. Johnson, Marjorie L. Brooks, Carys L. Mitchelmore, Daniel Schlenk

Sources of mercury to San Francisco Bay surface sediment as revealed by mercury stable isotopes

Mercury (Hg) concentrations and isotopic compositions were examined in shallow-water surface sediment (0–2 cm) from San Francisco (SF) Bay to determine the extent to which historic Hg mining contributes to current Hg contamination in SF Bay, and to assess the use of Hg isotopes to trace sources of contamination in estuaries. Inter-tidal and wetland sediment had total Hg (HgT) concentrations rangin
Authors
Gretchen E. Gehrke, Joel D. Blum, Mark Marvin-DePasquale

Projected evolution of California's San Francisco Bay-Delta-River System in a century of continuing climate change

Background Accumulating evidence shows that the planet is warming as a response to human emissions of greenhouse gases. Strategies of adaptation to climate change will require quantitative projections of how altered regional patterns of temperature, precipitation and sea level could cascade to provoke local impacts such as modified water supplies, increasing risks of coastal flooding, and growing
Authors
James E. Cloern, Noah Knowles, Larry R. Brown, Daniel Cayan, Michael D. Dettinger, Tara L. Morgan, David H. Schoellhamer, Mark T. Stacey, Mick van der Wegen, R. Wayne Wagner, Alan D. Jassby

PCB-induced changes of a benthic community and expected ecosystem recovery following in situ sorbent amendment

The benthic community was analyzed to evaluate pollution-induced changes for the polychlorinated biphenyl (PCB)-contaminated site at Hunters Point (HP) relative to 30 reference sites in San Francisco Bay, California, USA. An analysis based on functional traits of feeding, reproduction, and position in the sediment shows that HP is depauperate in deposit feeders, subsurface carnivores, and species
Authors
Elisabeth M.-L. Janssen, Janet K. Thompson, Samuel N. Luoma, Richard G. Luthy

Oxidative stress response of Forster's terns (Sterna forsteri) and Caspian terns (Hydroprogne caspia) to mercury and selenium bioaccumulation in liver, kidney, and brain

Bioindicators of oxidative stress were examined in prebreeding and breeding adult and chick Forster's terns (Sterna forsteri) and in prebreeding adult Caspian terns (Hydroprogne caspia) in San Francisco Bay, California. Highest total mercury (THg) concentrations (mean±standard error;μg/g dry wt) in liver (17.7±1.7), kidney (20.5±1.9), and brain (3.0±0.3) occurred in breeding adult Forster's terns.
Authors
David J. Hoffman, Collin A. Eagles-Smith, Joshua T. Ackerman, Terrence L. Adelsbach, Katherine R. Stebbins

Small-scale sediment transport patterns and bedform morphodynamics: New insights from high resolution multibeam bathymetry

New multibeam echosounder and processing technologies yield sub-meter-scale bathymetric resolution, revealing striking details of bedform morphology that are shaped by complex boundary-layer flow dynamics at a range of spatial and temporal scales. An inertially aided post processed kinematic (IAPPK) technique generates a smoothed best estimate trajectory (SBET) solution to tie the vessel motion-re
Authors
Patrick L. Barnard, Li H. Erikson, Rikk G. Kvitek

Bird mercury concentrations change rapidly as chicks age: Toxicological risk is highest at hatching and fledging

Toxicological risk of methylmercury exposure to juvenile birds is complex due to the highly transient nature of mercury concentrations as chicks age. We examined total mercury and methylmercury concentrations in blood, liver, kidney, muscle, and feathers of 111 Forster's tern (Sterna forsteri), 69 black-necked stilt (Himantopus mexicanus), and 43 American avocet (Recurvirostra americana) chicks as
Authors
Joshua T. Ackerman, Collin A. Eagles-Smith, Mark P. Herzog

Recent scientific advances and their implications for sand management near San Francisco, California: The influences of the ebb tidal delta

Recent research in the San Francisco, California, U.S.A., coastal region has identified the importance of the ebb tidal delta to coastal processes. A process-based numerical model is found to qualitatively reproduce the equilibrium size and shape of the delta. The ebb tidal delta itself has been contracting over the past century, and the numerical model is applied to investigate the sensitivity of
Authors
Daniel M. Hanes, Patrick L. Barnard, Kate Dallas, Edwin Elias, Li H. Erikson, Jodi Eshleman, Jeff Hansen, Tian Jian Hsu, Fengyan Shi