High nutrient pulses, tidal mixing and biological response in a small California estuary: Variability in nutrient concentrations from decadal to hourly time scales

Caffrey, Jane M.; Chapin, Thomas P.; Jannasch, Hans W.; Haskins, John

doi:10.1016/j.ecss.2006.08.015

Cited by 65 publications

(57 citation statements)

References 39 publications

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“…The average depth of the Slough is 2.5 m, with a main channel average depth of 6.5 m. The major fresh water source to the head of the estuary is the Carneros Creek, which is seasonal and has a flow range of 0-3.8 m 3 s −1 , depending on rainfall (Caffrey et al 2007). The Watsonville Creek is a secondary ephemeral stream that also supplies freshwater to the upper reaches of the slough below the Carneros Creek monitoring station (Fig.…”

Section: Study Areamentioning

confidence: 99%

“…Two decades later, ammonium and nitrate concentrations in the slough were generally an order of magnitude higher than those measured in South San Francisco Bay, where the dominant source of nutrients is from wastewater treatment plants (Nichols et al 1986;Hager and Schemel 1996). The nitrate concentration range currently measured in the Elkhorn Slough monthly water quality monitoring program is three orders of magnitude higher than those measured in Tomales Bay in the late 1990s (Caffrey et al 2007). Nitrate concentrations measured in the main channel of the Elkhorn Slough at Kirby Park from 2006 to 2007 are roughly double the concentrations measured in the same years in South San Francisco Bay (data comparison made using the SFEI RMP web query tool at http://eis.sfei.org/wqt and detailed in SFEI 2008).…”

Section: Introductionmentioning

confidence: 99%

“…It is clear that rainfall is linked to the transport of nutrients into the slough from terrestrial sources; however, it is possible that this is a more critical effect to consider when examining high temporal resolution data (Hewitt et al 2001). A more thorough discussion of wet vs. drought years effecting Elkhorn Slough water quality at higher temporal resolution can be found in Caffrey et al (2007). By using annual averages in our comparisons with BACI design, we are eliminating the seasonal component of nitrate dynamics both in our annual calculations and by subtracting Kirby nitrate concentrations, which were responding to the same meteorological forcing (Stewart-Oaten et al 1986).…”

Section: Rainfall Effects On Nutrient Concentrationsmentioning

confidence: 99%

“…Rainfall is, however, extremely variable to the slough on seasonal, annual, and interannual timescales. It has been documented that nitrate concentrations in various parts of the slough are the highest during the rainy season and are associated with pulses of freshwater runoff (Los Huertos et al 2001;Caffrey et al 2002aCaffrey et al , 2007Johnson, unpublished data). It has also been speculated that other nutrients follow similar patterns of increasing concentrations with rainfall and runoff events in the slough watershed (Caffrey et al 2002a).…”

Section: Rainfall Effects On Nutrient Concentrationsmentioning

confidence: 99%

“…These two stations are approximately 3,300 m (measured up the thalweg) from Kirby Park. Residence times in this upper region of the Slough range from 50 days during the dry season to 1 day during the rainy season (Largier et al 1997;Caffrey et al 2007). Mobilization of nutrients like nitrate tends to be the highest in response to precipitation and runoff processes during the winter, when residence times are quite short (Correll et al 1992;Chapin et al 2004).…”

Section: Study Areamentioning

confidence: 99%

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Signatures of Restoration and Management Changes in the Water Quality of a Central California Estuary

Gee

Wasson

Shaw

et al. 2010

Estuaries and Coasts

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Coastal managers and policy-makers are concerned with tracking improvements to water quality linked to management changes. Long-term water quality data acquired from two wetland areas in the upper reaches of the Elkhorn Slough estuary in central California were analyzed for signatures of land restoration or water control structure management. Post-restoration averaged NO 3 , NH 3 , and PO 4 concentrations were 50-70% less than before-restoration concentrations. Assessment of watershed-scale effects revealed that proximity of restoration to sampling locations had almost as strong an effect on water quality as the percentage of land restored relative to watershed size. Results also suggest that restoration of even 1% of an agriculturally intensive watershed such as that of the Elkhorn Slough may result in improvements to water quality. Finally, results indicate that tide gate function can dominate water quality in managed wetlands and must be carefully tracked and managed in the context of estuarine conservation targets.

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Section: Study Areamentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Rainfall Effects On Nutrient Concentrationsmentioning

confidence: 99%

Section: Rainfall Effects On Nutrient Concentrationsmentioning

confidence: 99%

Section: Study Areamentioning

confidence: 99%

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Signatures of Restoration and Management Changes in the Water Quality of a Central California Estuary

Gee

Wasson

Shaw

et al. 2010

Estuaries and Coasts

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The importance of climatic variability and human influence in driving aspects of temporarily open‐closed estuaries

Brooker

Scharler

2020

Ecohydrology

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Freshwater availability is a major topic in scientific literature and the public domain.Estuaries are complex and dynamic ecosystems that depend on freshwater inflow from their catchments and exchange with the marine environment. Catchment forcings are subject to shifts in frequency and intensity due to regional hydrological variability over time. Human manipulation of freshwater regimes may further alter this beyond natural variability through flow abstraction and additional inputs in the form of wastewater. To elucidate the effect of climate variability and human activities, we conducted a time series investigation on hydrological drivers into a small South African estuary (uMdloti), representative of temporarily open-closed estuaries. Subsequently, we investigated the ability of the hydrological variables to drive physical parameters and microalgae in the estuary. Freshwater abstraction caused a disconnect between rainfall and river flow, and increased lag times during dry spells, peaking at 115 days. Annual seasonal peaks in rainfall were not represented in river flow due to the dam. Wastewater discharges equate to 4% of the mean annual runoff from the catchment, which has reduced from a natural runoff of 85.8 to 71.9 Mm −3 year −1 . Due to this and damming of catchment flows, wastewater discharging into the estuary was the most important driver of water quality in the system, resulting in increased nutrient and decreased dissolved oxygen concentrations, whereas river flow was an important driver at high flow volumes. An understanding of interaction effects between climatic variability and catchment flow manipulation is vitally important to estuarine management and their ecological viability. K E Y W O R D S climatic variability, estuarine water quality, freshwater abstraction, hydrological drivers, intermittently open-closed lagoons, temporarily open-closed estuaries, wastewater treatment works

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Predicting burrowing crab impacts on salt marsh plants

2021

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Burrowing animals profoundly influence plant communities, and changes in the burrower and plant communities together with changing abiotic parameters can shift the influence of burrowers on plants. However, we lack an ability to predict when, where, and how burrowers will influence vegetation. To begin to understand how naturally, varying environmental conditions influence the impacts of burrowers, we need to examine how burrower impacts on marsh plants differ across sites differing in environmental conditions. We manipulated crab presence for multiple years and measured the responses of the dominant plants, Pacific cordgrass (Spartina foliosa) and perennial pickleweed (Sarcocornia pacifica), at three sites in northern California and two sites in southern California. Southern California (Point Conception, CA, to the U.S.–Mexico border) experiences higher air and water temperatures, lower precipitation, and higher porewater salinity levels. Combining data from these field studies with laboratory studies allowed us to generate predictions about burrowing crab effects in salt marshes. Our models included (1) an estimate of grazing pressure on marsh plants by the dominant burrowing crab (Pachygrapsus crassipes) and (2) several soil biogeochemical measurements. Crab effects varied from strongly positive to strongly negative and depended upon estimated crab grazing pressure and edaphic conditions (salinity, ammonium, and nitrate). Relative to crabs at other sites, crabs enhanced cordgrass at sites with intermediate levels of ammonium and extreme salinities. The dependence of crab effects on edaphic conditions suggests that projected interannual variability in temperature, precipitation, and nutrients could lead to more temporally variable impacts of crabs on cordgrass. Understanding the environmental controls on these interactions will help promote cordgrass productivity and stabilize salt marsh ecosystems.

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High nutrient pulses, tidal mixing and biological response in a small California estuary: Variability in nutrient concentrations from decadal to hourly time scales

Cited by 65 publications

References 39 publications

Signatures of Restoration and Management Changes in the Water Quality of a Central California Estuary

Signatures of Restoration and Management Changes in the Water Quality of a Central California Estuary

The importance of climatic variability and human influence in driving aspects of temporarily open‐closed estuaries

Predicting burrowing crab impacts on salt marsh plants

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