Long-term trends and causal factors associated with Microcystis abundance and toxicity in San Francisco Estuary and implications for climate change impacts

Lehman, Peggy W.; Marr, Kendrick L.; Boyer, Gregory L.; Acuña, Shawn

doi:10.1007/s10750-013-1612-8

Cited by 76 publications

(66 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…2B), although summer flows are greatly reduced from winter to spring. These years also include times of strong blooms of the toxic cyanobacterium Microcystis aeruginosa and times without blooms (Lehman et al, 2013), times of high rates of water diversion relative to inflow, and times of high and low abundance of planktivorous fishes (Sommer et al, 2007). We are mystified by this narrow range of abundance and what strong feedback mechanisms must exist to maintain it.…”

Section: Abundance and Flow Responsesmentioning

confidence: 99%

See 1 more Smart Citation

Effects of freshwater flow and phytoplankton biomass on growth, reproduction, and spatial subsidies of the estuarine copepod Pseudodiaptomus forbesi

et al. 2017

View full text Add to dashboard Cite

We examined how freshwater flow and phytoplankton biomass affected abundance and population dynamics of the introduced subtropical copepod Pseudodiaptomus forbesi in brackish and freshwater regions of the San Francisco Estuary, California, USA. This copepod is key prey for the endangered and food-limited delta smelt, Hypomesus transpacificus, in low-salinity water during summerautumn. Long-term monitoring data showed that P. forbesi was most abundant in fresh water, where summer-autumn abundance was invariant with freshwater flow. Abundance was positively related to freshwater flow in low-salinity water. Reproductive rates in both regions during 2010-2012 were low and unresponsive to chlorophyll or freshwater flow. Development indices, calculated as ratios of laboratory-derived to field-derived stage durations, were lowest for nauplii and highest for late copepodites, but averaged below 0.5 for all stages combined. Development indices were weakly related to chlorophyll for late copepodites only, unrelated to freshwater flow, and slightly higher in low-salinity than fresh water. Thus, the principal mechanism by which flow affects the P. forbesi population is apparently transport of copepods from fresh water to low-salinity water, where copepods are available to delta smelt. This work demonstrates how freshwater flow affects estuarine foodwebs through spatial subsidies of food supply.

show abstract

Section: Abundance and Flow Responsesmentioning

confidence: 99%

“…We cannot rule out effects of stress, although salinity stress is unlikely given the rather small differences in development indices between fresh and brackish water. Toxic stress is always a possibility in this estuary with its urban and agricultural land uses, and stress due to ingestion of Microcystis aeruginosa is likely (Lehman et al, 2013).…”

mentioning

confidence: 99%

Effects of freshwater flow and phytoplankton biomass on growth, reproduction, and spatial subsidies of the estuarine copepod Pseudodiaptomus forbesi

et al. 2017

View full text Add to dashboard Cite

show abstract

“…However, Microcystis blooms in the Delta have also been associated with high irradiance, increased water clarity, warm waters, and low flows (Lehman et al 2008(Lehman et al , 2013. Wastewater effluent also contains a large number of pharmaceutical and personal care products, which can have deleterious effects on aquatic organisms (Fong et al 2016).…”

Section: Wastewater Managementmentioning

confidence: 99%

Is Extinction Inevitable for Delta Smelt and Longfin Smelt? An Opinion and Recommendations for Recovery

Hobbs¹,

Moyle²,

Fangue³

et al. 2017

SFEWS

View full text Add to dashboard Cite

“…Several major factors affect cyanobacterial blooms, including salinity, irradiance, stratification, temperature, water residence time, and nutrient availability (Berg and Sutula 2015;Lehman et al 2013). Salinity gradients do not control the geographic distribution of cyanoHABs; common cyanobacteria have a broad range of salinity tolerance and can survive in brackish waters (Berg and Sutula 2015).…”

Section: Microcystis and Cyanobacterial Harmful Algal Blooms Overviewmentioning

confidence: 99%

Nutrient Dynamics of the Delta: Effects on Primary Producers

Dahm¹,

Parker²,

Adelson³

et al. 2016

SFEWS

View full text Add to dashboard Cite

Increasing clarity of Delta waters, the emergence of harmful algal blooms, the proliferation of aquatic water weeds, and the altered food web of the Delta have brought nutrient dynamics to the forefront. This paper focuses on the sources of nutrients, the transformation and uptake of nutrients, and the links of nutrients to primary producers. The largest loads of nutrients to the Delta come from the Sacramento River with the San Joaquin River seasonally important, especially in the summer. Nutrient concentrations reflect riverine inputs in winter and internal biological processes during periods of lower flow with internal nitrogen losses within the Delta estimated at approximately 30% annually. Light regime, grazing pressure, and nutrient availability influence rates of primary production at different times and locations within the Delta. The roles of the chemical form of dissolved inorganic nitrogen in growth rates of primary producers in the Delta and the structure of the open-water algal community are currently topics of much interest and considerable debate. Harmful algal blooms have been noted since the late 1990s, and the extent of invasive aquatic macrophytes (both submerged and free-floating forms) has increased especially during years of drought. Elevated nutrient loads must be considered in terms of their ability to support this excess biomass. Modern sensor technology and networks are now deployed that make high-frequency measurements of nitrate, ammonium, and phosphate. Data from such instruments allow a much more detailed assessment of the spatial and temporal dynamics of nutrients. Four fruitful directions for future research include utilizing continuous sensor data to estimate rates of primary production and ecosystem respiration, linking hydrodynamic models of the Delta with the transport and fate of dissolved nutrients, studying nutrient dynamics in various habitat types, and exploring the use of stable isotopes to trace the movement and fate of effluent-derived nutrients.

show abstract

Long-term trends and causal factors associated with Microcystis abundance and toxicity in San Francisco Estuary and implications for climate change impacts

Cited by 76 publications

References 62 publications

Effects of freshwater flow and phytoplankton biomass on growth, reproduction, and spatial subsidies of the estuarine copepod Pseudodiaptomus forbesi

Effects of freshwater flow and phytoplankton biomass on growth, reproduction, and spatial subsidies of the estuarine copepod Pseudodiaptomus forbesi

Is Extinction Inevitable for Delta Smelt and Longfin Smelt? An Opinion and Recommendations for Recovery

Nutrient Dynamics of the Delta: Effects on Primary Producers

Contact Info

Product

Resources

About