Characterization of the Microcystis Bloom and Its Nitrogen Supply in San Francisco Estuary Using Stable Isotopes

Lehman, Peggy W.; Kendall, Carol; Guérin, Mathieu; Young, M. B.; Silva, S. R.; Boyer, Gregory L.

doi:10.1007/s12237-014-9811-8

Cited by 39 publications

(29 citation statements)

References 55 publications

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“…There are two ways by which nutrients can enter the reservoir: exogenous input and endogenous release. Exogenous input mainly comes from rainfall-induced runoff, whose primary nitrogen source is NO 3 ¡ (Rabalais 2002;Lehman et al 2015), whereas NH 4 C is the primary form of nitrogen if released from the sediment under anaerobic conditions (Reddy et al 1996). Given the similar thermal stratification and sediment properties of the Zhoucun Reservoir in 2013 and 2014, the amount of nutrients discharged from the sediment probably varied little between the two years.…”

Section: Discussionmentioning

confidence: 99%

Differences in phytoplankton dynamics and community structure between a wet year and dry year in the Zhoucun Reservoir

Qiu

Zeng

2016

Journal of Freshwater Ecology

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Rainfall-induced nutrient fluctuations in surface water affect phytoplankton communities and cause algal blooms. To examine this influence in the Zhoucun Reservoir, China, field surveys were performed weekly or biweekly from February 2013 (a wet year) to December 2014 (a dry year). Physical conditions, nutrient levels, and phytoplankton functional groups were investigated during monitoring. Nutrient levels increased in the summer of 2013 (TN: 0.85À2.66 mg/L; TP: 0.037À0.138 mg/L), while nitrogen deficiency occurred in the summer of 2014 (TN: 0.38À0.73 mg/L, TP: 0.044À0.079 mg/L). A cyanobacteria bloom that appeared in the summer of 2013 had the dominant phytoplankton functional groups M and Tc. In the summer of 2014, algal cell density and biomass were much lower than those during the corresponding period in 2013, and the co-dominant phytoplankton groups were F, L 0 , Tc, and S2. Non-N-fixing cyanobacteria were not abundant in summer 2013 probably because of the low ratio of NO 3 ¡ to NH 4 C , although nitrogen was also deficient. In contrast to these summer trends, little difference was noted between phytoplankton dynamics and community structure in the two winters and two springs, regardless of nutrient conditions. Redundancy analysis indicated that rainfall-induced nitrogen fluctuations were the primary factor causing phytoplankton dynamics to differ between the wet and dry year. The effects of water temperature, stratification, and light on the phytoplankton community were independent of nutrient fluctuations. This study shows that rainfall fluctuations change summer nutrient conditions and that cyanobacteria blooms are likely to occur in wet years in the Zhoucun Reservoir.

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Section: Discussionmentioning

confidence: 99%

Differences in phytoplankton dynamics and community structure between a wet year and dry year in the Zhoucun Reservoir

Qiu

Zeng

2016

Journal of Freshwater Ecology

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“…On a spatial scale, the presence of cyanobacterial species varied. Microcystis spp., the most common cyanobacterial species, appear mainly in the upper, freshwater zones of estuaries [39,40]. Their photosynthetic efficiency diminishes while moving down the estuary [41]; therefore, the abundance of the toxic species decreases downstream [21].…”

Section: Temporal and Spatial Dynamics Of Cyanobacteriamentioning

confidence: 99%

Spatial and Temporal Dynamics of Potentially Toxic Cyanobacteria in the Riverine Region of a Temperate Estuarine System Altered by Weirs

Malazarte

Lee

Kim

et al. 2017

Water

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Abstract:The effects of weirs on fish and other biological communities have garnered considerable study, whereas the effects of weirs on community composition of toxic cyanobacteria have not yet been well documented. In this study, temporal and spatial variations in species composition and the abundance of potentially toxic cyanobacteria were investigated in the riverine regions of the temperate Youngsan River estuary, where two weirs have recently been constructed. Four stations were sampled 0.5 m below the surface monthly along the channel of the upper river from May 2014 to April 2015 to explore cyanobacterial composition and abundance, while physicochemical and biological parameters were measured to elucidate possible mechanisms controlling these dynamics. Two stations were located upstream at free-flowing sites, and the other stations were located downstream at impounded sites near the weirs. Twenty-eight cyanobacterial species were identified, seven of which were potentially toxic: Microcystis sp., M. aeruginosa, M. flos-aquae, Dolichospermum sp., Aphanocapsa sp., Oscillatoria sp. and Phormidium sp. Microcystis sp. was the most abundant in June 2014 at the lowest station near the weir. Meanwhile, Phormidium sp. occurred at low abundance throughout the study period, except during the winter months, when its abundance was elevated. The interactive forward selection method highlighted dissolved inorganic nitrogen and zooplankton abundance as explanatory variables for this observed variation, but their effects on cyanobacterial growth are unclear. However, temperature was the major determinant for the temporal variation in cyanobacterial populations. Cluster analysis showed that the downstream stations near the weirs had a high similarity of potentially toxic cyanobacteria. Significantly higher abundance, especially of Microcystis sp., was also recorded at the impounded sites suggesting that the presence of weirs might affect variations in toxic cyanobacterial communities.

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“…However, the presence of ammonium has been shown to inhibit the transport of nitrate into phytoplankton cells (e.g., He et al 2004;Song and Ward 2007) as well as inhibiting the manufacture of the enzymes necessary for nitrate assimilation (Eppley et al 1969;Vergera et al 1998), and so the terms "inhibition" or "repression" have also been used to describe the phenomenon. In locations where it has been tested ([1] the three embayments of the northern estuary, Wilkerson et al 2006;Dugdale et al 2007;[2] the Sacramento River, Parker et al 2012b, and [3]the San Joaquin River, Lehman et al 2015;Parker, unpublished; Figure 5), results suggest that ammonium inhibition of nitrate is a universal feature of the estuary and Delta. A review of ammonium in Suisun Bay (Senn and Novick 2014b) concludes that there is "strong support" that ammonium inhibition of nitrate uptake does occur in the estuary.…”

Section: The Ammonium Paradoxmentioning

confidence: 99%

“…The emergence of blooms of the toxic cyanobacteria, Microcystis aeruginosa (Microcystis), starting about 1999, has generated questions about the sources of nutrients needed to sustain these blooms (Lehman et al 2015). The proliferation of invasive aquatic macrophytes within the Delta, especially Egeria densa (Brazilian waterweed) and Eichhornia crassipes (water hyacinth), has also raised questions about the sources of nutrients that support summertime coverage of up to 15% of the Delta's waterways by submerged and floating aquatic vegetation (Santos et al 2009).…”

Section: Introductionmentioning

confidence: 99%

Nutrient Dynamics of the Delta: Effects on Primary Producers

Dahm¹,

Parker²,

Adelson³

et al. 2016

SFEWS

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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.

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Characterization of the Microcystis Bloom and Its Nitrogen Supply in San Francisco Estuary Using Stable Isotopes

Cited by 39 publications

References 55 publications

Differences in phytoplankton dynamics and community structure between a wet year and dry year in the Zhoucun Reservoir

Differences in phytoplankton dynamics and community structure between a wet year and dry year in the Zhoucun Reservoir

Spatial and Temporal Dynamics of Potentially Toxic Cyanobacteria in the Riverine Region of a Temperate Estuarine System Altered by Weirs

Nutrient Dynamics of the Delta: Effects on Primary Producers

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