Gregory G. Shellenbarger

Fecal indicator bacteria and Salmonella in ponds managed as bird habitat, San Francisco Bay, California, USA.

Throughout the world, coastal resource managers are encouraging the restoration of previously modified coastal habitats back into wetlands and managed ponds for their ecosystem value. Because many coastal wetlands are adjacent to urban centers and waters used for human recreation, it is important to understand how wildlife can affect water quality. We measured fecal indicator bacteria (FIB) concentrations, presence/absence of Salmonella, bird abundance, and physico-chemical parameters in two coastal, managed ponds and adjacent sloughs for 4 weeks during the summer and winter in 2006. We characterized the microbial water quality in these waters relative to state water-quality standards and examined the relationship between FIB, bird abundance, and physico-chemical parameters. A box model approach was utilized to determine the net source or sink of FIB in the ponds during the study periods. FIB concentrations often exceeded state standards, particularly in the summer, and microbial water quality in the sloughs was generally lower than in ponds during both seasons. Specifically, the inflow of water from the sloughs to the ponds during the summer, more so than waterfowl use, appeared to increase the FIB concentrations in the ponds. The box model results suggested that the ponds served as net wetland sources and sinks for FIB, and high bird abundances in the winter likely contributed to net winter source terms for two of the three FIB in both ponds. Eight serovars of the human pathogen Salmonella were isolated from slough and pond waters, although the source of the pathogen to these wetlands was not identified. Thus, it appeared that factors other than bird abundance were most important in modulating FIB concentrations in these ponds.

Bacterial Contamination and Submarine Groundwater Discharge—A Possible Link

Environmental Context.Pathogenic bacteria and viruses are sometimes detected in coastal waters, high levels of which correlate with occurrence of acute gastrointestinal illness in recreational beach users. The source of the bacterial and viral contamination to the beach is not always easy to decipher, and therefore efforts to prevent these occurrences are limited by lack of full understanding of their cause. Abstract.Beach water contamination by pathogenic agents is monitored by Fecal Indicator Bacteria (FIB) levels. A source of these agents may be submarine groundwater discharge. At Huntington Beach, California high FIB levels in the surf zone are shown to be associated with high 224Ra and 223Ra activities, indicators of groundwater discharge.

Unintended consequences of management actions in salt pond restoration: cascading effects in trophic interactions.

Salt evaporation ponds have played an important role as habitat for migratory waterbirds across the world, however, efforts to restore and manage these habitats to maximize their conservation value has proven to be challenging. For example, salinity reduction has been a goal for restoring and managing former salt evaporation ponds to support waterbirds in the South Bay Salt Pond Restoration Project in San Francisco Bay, California, USA. Here, we describe a case study of unexpected consequences of a low-dissolved oxygen (DO) event on trophic interactions in a salt pond system following management actions to reduce salinity concentrations. We document the ramifications of an anoxic event in water quality including salinity, DO, and temperature, and in the response of the biota including prey fish biomass, numerical response by California Gulls (Larus californicus), and chick survival of Forsters Tern (Sterna forsteri). Management actions intended to protect receiving waters resulted in decreased DO concentrations that collapsed to zero for ≥ 4 consecutive days, resulting in an extensive fish kill. DO depletion likely resulted from an algal bloom that arose following transition of the pond system from high to low salinity as respiration and decomposition outpaced photosynthetic production. We measured a ≥ 6-fold increase in biomass of fish dropped on the levee by foraging avian predators compared with weeks prior to and following the low-DO event. California Gulls rapidly responded to the availability of aerobically-stressed and vulnerable fish and increased in abundance by two orders of magnitude. Mark-recapture analysis of 254 Forsters Tern chicks indicated that their survival declined substantially following the increase in gull abundance. Thus, management actions to reduce salinity concentrations resulted in cascading effects in trophic interactions that serves as a cautionary tale illustrating the importance of understanding the interaction of water quality and trophic structure when managing restoration of salt ponds.

Continuous Salinity and Temperature Data from San Francisco Estuary, 1982–2002: Trends and the Salinity–Freshwater Inflow Relationship

Abstract The U.S. Geological Survey and other federal and state agencies have been collecting continuous temperature and salinity data, two critical estuarine habitat variables, throughout San Francisco estuary for over two decades. Although this dynamic, highly variable system has been well studied, many questions remain relating to the effects of freshwater inflow and other physical and biological linkages. This study examines up to 20 years of publically available, continuous temperature and salinity data from 10 different San Francisco Bay stations to identify trends in temperature and salinity and quantify the salinity–freshwater inflow relationship. Several trends in the salinity and temperature records were identified, although the high degree of daily and interannual variability confounds the analysis. In addition, freshwater inflow to the estuary has a range of effects on salinity from −0.0020 to −0.0096 (m3 s−1) −1 discharge, depending on location in the estuary and the timescale of analyzed data. Finally, we documented that changes in freshwater inflow to the estuary that are within the range of typical management actions can affect bay-wide salinities by 0.6–1.4. This study reinforces the idea that multidecadal records are needed to identify trends from decadal changes in water management and climate and, therefore, are extremely valuable.

Erratum to: Measuring sediment accretion in early tidal marsh restoration

Erratum to: Wetlands Ecol ManageDOI 10.1007/s11273-009-9170-6In the original publication under the section Discus-sion, the sedimentation rates are incorrectly published.The corrected version is given below.In San Pablo Bay where there is a large supply ofsediment (Jaffe et al. 1998), we measured sedimentaccretion of up to 64.9 cm/year at a single sedimentpin in the third year of the Tubbs Setback restoration(8-year average sedimentation rate of 16.8 cm/year).Sediment accretion was higher at this site comparedto other San Pablo Bay restoration sites that rangedfrom a 10-year average sedimentation rate of 2.0 cm/year (Tolay Creek: author’s unpublished data) to an8-year average sedimentation rate of 6.2 cm/year(Guadalcanal: Woo et al. 2008).

Science support for salt pond restoration and management in south San Francisco Bay

United States is underway on 16,500 acres of salt evaporation ponds in San Francisco Bay. More than 85 percent of historic tidal marsh acreage has been lost from diking and filling in the San Francisco Bay Estuary. The South Bay Salt Pond Restoration Project will restore thousands of acres of marshlands that will enhance ecosystem functions by improving water quality and adding habitat for endangered species. It will also create a system of managed ponds to provide habitat and food (e.g., brine shrimp and brine flies) for migrating and wintering waterbirds. The salt ponds were purchased by state and federal agencies in March of 2003. The restoration process is being managed collaboratively by the U.S. Fish and