The effect of inorganic nitrogen speciation on primary production in the San Francisco Estuary

Parker, Alexander E.; Hogue, Victoria E.; Wilkerson, Frances P.; Dugdale, Richard C.

doi:10.1016/j.ecss.2012.04.001

Cited by 47 publications

(49 citation statements)

References 65 publications

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“…10d) was not observed in the data, where NO 3 uptake begins to increase in the last two days, as NO 3 concentrations in the enclosures begins to decrease. Some unknown factor appears to be selectively depressing NO 3 uptake in the Suisun Bay enclosure (Parker et al, 2012a). Trace metal leakage from paint from a large number of anchored naval ships (the U.S.…”

Section: Enclosures From the Northern Estuary ("Bad Suisun 3") Experimentioning

confidence: 99%

“…The SFE biogeochemical model incorporates kinetic parameters from the CoSiNE model , appropriate for diatoms which are the major functional group that dominates the final population in enclosure experiments in SFE and in phytoplankton blooms in Suisun Bay (Parker et al, 2012a;Dugdale et al, 2012;Cloern and Dufford, 2005). Diatoms are fast-growing and outcompete other phytoplankton in high nutrient conditions, e.g.…”

Section: Model Development and Constructionmentioning

confidence: 99%

“…2 (taken from Dugdale et al, 2007) that has been repeatedly observed (e.g. Parker et al, 2012a). First NH 4 concentrations decreased and then NO 3 concentrations decreased rapidly to zero within four days ( Fig.…”

Section: Introductionmentioning

confidence: 99%

“…NO 3 uptake is essential for high productivity rates and phytoplankton bloom occurrence as NO 3 is the largest reservoir of DIN in the SFE Dugdale et al, 2012). Decreased phytoplankton growth rates and reduced carbon fixation (primary production) occurred when the algae were using NH 4 compared to NO 3 Parker et al, 2012a). When chlorophyll concentrations and NO 3 uptake rates were plotted against NH 4 concentration, a threshold of about 4 mol L −1 NH 4 appeared to delineate the level at which suppression of NO 3 uptake occurred.…”

Section: Introductionmentioning

confidence: 99%

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A biogeochemical model of phytoplankton productivity in an urban estuary: The importance of ammonium and freshwater flow

Dugdale

Wilkerson

Parker

2013

Ecological Modelling

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a b s t r a c tIncreased discharge of ammonium (NH 4 ) to the San Francisco Estuary (SFE), largely in treated domestic sewage effluent, has been linked to chronically food-limited conditions and to reduced fish abundance. Elevated chlorophyll concentrations at phytoplankton bloom levels are rarely observed if the ambient NH 4 concentrations are above 4 mol L −1 -the NH 4 paradox. In both field samples and water held in enclosures for one week, an inverse relation was observed between NH 4 concentrations and nitrate (NO 3 ) uptake by phytoplankton, likely a result of inhibition of NO 3 uptake by NH 4 . A simple model was constructed to examine the interaction between NH 4 and NO 3 inputs to the estuary, with varying freshwater river flow (hereafter termed flow) conditions. Sensitivity analyses were made and initial model parameters taken from an existing oceanic biogeochemistry model. Experiments were made with the model, and showed that initial NH 4 concentrations largely controlled the length of time to peak NO 3 uptake and NO 3 exhaustion. The model parameters were then tuned using observations from a set of enclosure experiments, and validated with results from a series of independent enclosure experiments with a variety of initial conditions. The model was run in three flow modes: (1) with no (zero) flow, (2) with flow, a fully mixed water column and a uniform light field, and (3) with flow, a fully mixed water column but with light attenuation and depth integrated values of N uptake. In the zero flow mode the model simulated enclosure experiments and when compared with enclosure results indicated the basic NH 4 -NO 3 interactions to be correctly represented in the model. In the modes with flow, the model simulations reproduced a sharp transition from high phytoplankton productivity using both NO 3 and NH 4 to low productivity using only NH 4 , simulating the historical effects of increasing NH 4 inputs to the SFE. With vertical integration to incorporate effects of irradiance, sharp boundaries at specific combinations of varying flow and NH 4 inputs were observed. The model could be embedded into three dimensional models of the SFE/Delta currently being implemented for management purposes such as regulating estuarine nutrients as required by the State of California and evaluating the effects of water management decisions on salmon and protected species of fish.

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Section: Enclosures From the Northern Estuary ("Bad Suisun 3") Experimentioning

confidence: 99%

Section: Model Development and Constructionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A biogeochemical model of phytoplankton productivity in an urban estuary: The importance of ammonium and freshwater flow

Dugdale

Wilkerson

Parker

2013

Ecological Modelling

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“…Because terrestrial plant matter, periphyton, and macrophytes have C : N ratios > 10, POM with a C : N ratio near the Redfield ratio (6.6 to 8.3) has been used to identify POM primarily composed of phytoplankton (Redfield, 1958;Thorp et al, 1998;Kendall et al, 2001). Similarly, a ratio of C : Chl a less than 200 has been used to identify POM of algal origin, with C : Chl a values above 200 indicating the presence of significant detrital material (Parsons et al, 1961;Cifuentes et al, 1989;Liu et al, 2007;Miller et al, 2013).…”

Section: Introductionmentioning

confidence: 99%

Use of Flow Cytometry and Stable Isotope Analysis to Determine Phytoplankton Uptake of Wastewater Derived Ammonium in a Nutrient-rich River

Schmidt¹

University of San Francisco Scholarship Repository

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Abstract. Anthropogenic alteration of the form and concentration of nitrogen (N) in aquatic ecosystems is widespread. Understanding availability and uptake of different N sources at the base of aquatic food webs is critical to establishment of effective nutrient management programs. Stable isotopes of N ( 14 N, 15 N) are often used to trace the sources of N fueling aquatic primary production, but effective use of this approach requires obtaining a reliable isotopic ratio for phytoplankton.In this study, we tested the use of flow cytometry to isolate phytoplankton from bulk particulate organic matter (POM) in a portion of the Sacramento River, California, during riverscale nutrient manipulation experiments that involved halting wastewater discharges high in ammonium (NH + 4 ). Field samples were collected using a Lagrangian approach, allowing us to measure changes in phytoplankton N source in the presence and absence of wastewater-derived NH

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Use of Toxicity Identification Evaluation Procedures to Clarify the Relationship Between Ammonium Concentrations and Phytoplankton Blooms in the San Francisco Bay Estuary, California, USA

Miller¹,

Bailey

Walker³

et al. 2022

Enviro Toxic and Chemistry

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Phytoplankton blooms in the northern San Francisco Bay Estuary have historically supported much of the larval fish production in the estuary. In the past, blooms were limited largely by reduced light intensities and net outflows through the system, as well as dense populations of introduced clams that continuously filter the water column. Conversely, the estuary is exposed to a wide variety of contaminants that may also impact phytoplankton growth. Interestingly, previous investigations have suggested that relatively low concentrations of ammonium may inhibit development of bloom conditions by interfering with nitrate assimilation. Given the complex dynamics of the system, with multiple factors that could potentially affect algal growth, additional data to validate this hypothesis are important to identify appropriate management options. Consequently, toxicity identification evaluation (TIE) procedures were applied to ambient water samples and monitored for 72-96 h under controlled conditions to evaluate their effects on algal growth and utilization of dissolved inorganic nitrogen. The TIE treatments specifically targeted ammonium, as well as the potential contributions of metals and nonpolar organic contaminants. Notably, all samples exhibited positive growth over the exposure period with no evidence of toxicity, and TIE treatments did not further improve growth. A subsequent 72-h study evaluated the effect of ammonium up to 12 µM at a fixed concentration of nitrate was monitored at 24-h intervals and showed no inhibition of the development of bloom conditions. Collectively, there was no evidence that ammonium interfered with growth, even at concentrations well above the range of postulated effect levels. Of additional interest, the lack of increased growth in TIE treatments targeting chelatable metals and nonpolar organics suggested that these contaminant classes were not present at inhibitory concentrations. These results demonstrate the importance of validation of cause in multistressor environments, and further clarify the roles of different factors that may limit development of bloom conditions in the estuary.

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The effect of inorganic nitrogen speciation on primary production in the San Francisco Estuary

Cited by 47 publications

References 65 publications

A biogeochemical model of phytoplankton productivity in an urban estuary: The importance of ammonium and freshwater flow

A biogeochemical model of phytoplankton productivity in an urban estuary: The importance of ammonium and freshwater flow

Use of Flow Cytometry and Stable Isotope Analysis to Determine Phytoplankton Uptake of Wastewater Derived Ammonium in a Nutrient-rich River

Use of Toxicity Identification Evaluation Procedures to Clarify the Relationship Between Ammonium Concentrations and Phytoplankton Blooms in the San Francisco Bay Estuary, California, USA

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