Sudden Clearing of Estuarine Waters upon Crossing the Threshold from Transport to Supply Regulation of Sediment Transport as an Erodible Sediment Pool is Depleted: San Francisco Bay, 1999

Schoellhamer, David H.

doi:10.1007/s12237-011-9382-x

Cited by 104 publications

(111 citation statements)

References 50 publications

(65 reference statements)

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“…Like many other urbanized estuaries around the world, the SFE has experienced perturbations in key ecosystem drivers, including sediment and nutrient loads (Schoellhamer 2011;Jassby 2008), quantity and diversity of toxic pollutants (Brooks et al 2012), decreased phytoplankton biomass, and a loss of diatoms (e.g., Alpine and Cloern 1992;Kimmerer 2004;Dugdale et al 2007), and changes in zooplankton and fish (Mueller-Solger et al 2002;Kimmerer 2005). Although the original authors of the light-utilization model for the SFE (Cole and Cloern 1984) predicted that the empirical efficiency factor y would likely respond to such changes, this parameter has been previously recalculated for the northern estuary only twice (Alpine and Cloern 1992;Jassby et al 2002).…”

Section: Discussionmentioning

confidence: 99%

“…Phytoplankton community structure was likely altered via size-selective grazing by the clams (Werner and Hollibaugh 1993) although additional drivers, including pesticides (Brooks et al 2012), changing nitrogen-to-phosphorus ratio (Glibert et al 2011), and increased ammonium loads (Dugdale et al 2007;Glibert et al 2011;) have also been implicated. At the same time, reduced sediment loads to the northern SFE, a consequence of damming upstream tributaries (Jassby 2008;Schoellhamer 2011) has resulted in increased water transparency and more favorable conditions for phytoplankton growth.…”

Section: Introductionmentioning

confidence: 99%

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Reevaluating the Generality of an Empirical Model for Light-Limited Primary Production in the San Francisco Estuary

Parker

Kimmerer

Lidström

2012

Estuaries and Coasts

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Depth-integrated primary production (ΣP, in grams of carbon per square meter per day) was measured using 14 C in the northern San Francisco Estuary (SFE) from March through August of 2006 and 2007. Determinations of ΣP were then used to calibrate a published light-utilization model that relates ΣP to a composite parameter of chlorophyll, solar irradiance, and photic zone depth. The resultant calibration coefficient, y, varied by a factor of nearly two between 2006 and 2007 and was lower than determined in previous calibrations for the estuary. The now chronically low chlorophyll concentrations in the SFE have resulted in lower predictive power of the lightutilization model. The variation in y was likely the result of interannual variation in phytoplankton assimilation number. These results suggest that using a single y may yield large errors in estimated estuarine production when applied overbroad spatial and temporal scales. Given the food-limited condition of the SFE, it appears that direct measurements of primary production are necessary for accurately characterizing the base of the estuarine food web.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Reevaluating the Generality of an Empirical Model for Light-Limited Primary Production in the San Francisco Estuary

Parker

Kimmerer

Lidström

2012

Estuaries and Coasts

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“…During episodic storms, wave-induced seabed shear stress can be significantly increased and sediment resuspension may occur in water depths of up to 20 m; however, such extreme events are relatively rare. Although wind-driven waves are important in controlling bed shear stress and SSC in the exposed intertidal wetland of the Yangtze Delta (Shi et al 2012), the The three figures correspond to pre-TGD periods of 1992-1993, 1999-2000, and June 2002-May 2003, respectively Estuaries and Coasts (2012) 35:1316-1327area of exposed intertidal wetland is very small in comparison with the extensive estuarine and adjacent coastal waters (Fig. 1b).…”

Section: Importance Of Tides In Controlling Short-term Variations In mentioning

confidence: 99%

“…The response of SSC in estuarine and adjacent waters to human activities, however, has seldom been addressed (Schoellhamer 2011), probably due to a lack of adequate datasets. In the present study, annually averaged SSCs derived from twice-daily data measured at multiple gauging stations during the period 1992-2009 show an overall significant decline (Table 2 and Fig.…”

Section: Surface Ssc In the Yangtze Estuary In Response To Decreasingmentioning

confidence: 99%

Spatial, Temporal, and Human-Induced Variations in Suspended Sediment Concentration in the Surface Waters of the Yangtze Estuary and Adjacent Coastal Areas

Yang

Milliman

et al. 2012

Estuaries and Coasts

110

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To delineate temporal and spatial variations in suspended sediment concentration (SSC) in the Yangtze (Changjiang) Estuary and adjacent coastal waters, surfacewater samples were taken twice daily from 10 stations over periods ranging from 2 to 12 years (total number of samples >28,000). Synoptic measurements in 2009 showed an increase in surface SSC from 0.058 g/l in the upper sections of the estuary to ∼0.6 g/l at the Yangtze River turbidity maximum at the river mouth, decreasing seaward to 0.057 g/l. Annual periodicities reflect variations in the Yangtze discharge, which affect the horizontal distribution and transport of SSC, and seasonal winds, which result in vertical resuspension and mixing. Over the past 10-20 years, annual surface SSC in the lower Yangtze River and the upper estuary has decreased by 55%, due mainly to dam construction in the upper and middle reaches of the river. The 20-30% decrease in mean surface SSC in the lower estuary and adjacent coastal waters over the same period presumably reflects sediment resuspension, in part due to erosion of the subaqueous Yangtze Delta. SSCs in the estuary and adjacent coastal waters are expected to continue to decline as new dams are constructed in the Yangtze basin and as erosion of the subaqueous delta slows in coming decades.

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“…High turbidity levels attenuate light penetration in the water column limiting primary production, define habitat conditions for endemic species (Brown et al 2013), nourish marshes and tidal flats, and carry nutrients and contaminants to intertidal and coastal areas. Natural and anthropogenic changes in environmental conditions modify the sediment dynamics, turbidity levels, and the system's resilience to future impacts (Hestir et al 2013;Schoellhamer 2011;Winterwerp and Wang 2013).…”

Section: Introductionmentioning

confidence: 99%

How can climate change and engineered water conveyance affect sediment dynamics in the San Francisco Bay-Delta system?

et al. 2017

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Suspended sediment concentration is an important estuarine health indicator. Estuarine ecosystems rely on the maintenance of habitat conditions, which are changing due to direct human impact and climate change. This study aims to evaluate the impact of climate change relative to engineering measures on estuarine fine sediment dynamics and sediment budgets. We use the highly engineered San Francisco Bay-Delta system as a case study. We apply a process-based modeling approach (Delft3D-FM) to assess the changes in hydrodynamics and sediment dynamics resulting from climate change and engineering scenarios. The scenarios consider a direct human impact (shift in water pumping location), climate change (sea level rise and suspended sediment concentration decrease), and abrupt disasters (island flooding, possibly as the results of an earthquake). Levee failure has the largest impact on the hydrodynamics of the system. Reduction in sediment input from the watershed has the greatest impact on turbidity levels, which are key to primary production and define habitat conditions for endemic species. Sea level rise leads to more sediment suspension and a net sediment export if little room for accommodation is left in the system due to continuous engineering works. Mitigation measures like levee reinforcement are effective for addressing direct human impacts, but less effective for a persistent, widespread, and increasing threat like sea level rise. Progressive adaptive mitigation measures to the changes in sediment and flow dynamics Climatic Change (2017) resulting from sea level rise may be a more effective strategy. Our approach shows that a validated process-based model is a useful tool to address long-term (decades to centuries) changes in sediment dynamics in highly engineered estuarine systems. In addition, our modeling approach provides a useful basis for long-term, process-based studies addressing ecosystem dynamics and health.

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Sudden Clearing of Estuarine Waters upon Crossing the Threshold from Transport to Supply Regulation of Sediment Transport as an Erodible Sediment Pool is Depleted: San Francisco Bay, 1999

Cited by 104 publications

References 50 publications

Reevaluating the Generality of an Empirical Model for Light-Limited Primary Production in the San Francisco Estuary

Reevaluating the Generality of an Empirical Model for Light-Limited Primary Production in the San Francisco Estuary

Spatial, Temporal, and Human-Induced Variations in Suspended Sediment Concentration in the Surface Waters of the Yangtze Estuary and Adjacent Coastal Areas

How can climate change and engineered water conveyance affect sediment dynamics in the San Francisco Bay-Delta system?

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