Variability in Inorganic and Organic Nitrogen Uptake Associated with Riverine Nutrient Input in the Gulf of Riga, Baltic Sea

Berg, Gry Mine; Glibert, Patricia M.; Jørgensen, Niels O. G.; Balode, Maija; Puriņa, Ingrīda

doi:10.2307/1352945

Cited by 60 publications

(40 citation statements)

References 78 publications

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“…in both fresh and marine systems (Berman & Chava 1999, Collier et al 1999, Sakamoto & Bryant 2001. Other cyanobacteria have also been shown to respond positively to organic nitrogen additions: Aphanizomenon ovalisporum used DON as its nitrogen source in Lake Kinneret, Israel (Berman 1997(Berman , 2001, and DON (urea and amino acids) contributed significantly to a filamentous cyanobacterial bloom in the Gulf of Riga, Baltic Sea (Berg et al 2001(Berg et al , 2003. The correlation reported here between zeaxanthin and percent urea uptake (Fig.…”

Section: Discussionsupporting

confidence: 52%

Evidence for dissolved organic nitrogen and phosphorus uptake during a cyanobacterial bloom in Florida Bay

Glibert¹,

Heil²,

Hollander³

et al. 2004

Mar. Ecol. Prog. Ser.

169

121

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Florida Bay, a shallow, seagrass-dominated bay in southern Florida, USA, receives significant nutrient inputs and has experienced seagrass losses and microalgal blooms within the last several decades. Inorganic nutrient inputs have been well characterized, but the role of organic nutrients, specifically of dissolved organic nitrogen (DON) and organic phosphorus (DOP), in supporting microbial processes in the bay is unknown. In this study various techniques were used to assess the importance of these nutrients along a transect in Florida Bay when a cyanobacterial bloom occurred in the central region in November 2002. These techniques included measurements of ambient particulate and dissolved nutrients, enzyme (urease and alkaline phosphatase) activities, and experiments to determine rates of 15 N uptake (nitrate, ammonium, urea, and amino acids over a period of 0.5 h) and long-term (48 h) changes in microbial biomass and 15 N natural abundance in enrichment bioassays. The cyanobacterial bloom in central Florida Bay was associated with the highest concentrations of DON and DOP, whereas the microflagellate-and diatom-dominated eastern bay region was associated with the highest concentrations of inorganic nutrients. The zeaxanthin:chlorophyll a ratio (an indicator of the relative contribution of cyanobacteria to phytoplankton biomass) was positively correlated with the rate of uptake of urea, and negatively correlated with the rate of uptake of inorganic nitrogen. The opposite pattern was observed for the fucoxanthin:chlorophyll a ratio (indicative of relative diatom biomass) and the peridinin:chlorophyll a ratio (indicative of relative photosynthetic dinoflagellate biomass), suggesting that different algal groups were using different N substrates. Biomass responses in the bioassay experiments showed that phytoplankton (as chlorophyll a) responded to DON additions in the western region and to DOP additions in the eastern region, but heterotrophic bacteria, in contrast, responded to DOP additions in the west and DON additions in the east. These findings thus demonstrate the potential for different sources of N, including DON, to stimulate different components of the algal community, and for the phytoplankton and bacteria to respond differently to N and P.KEY WORDS: Florida Bay · Cyanobacteria · Organic N · Organic P · Nutrient limitation · Urease · Alkaline phosphatase · Bioassay · Nutrient uptake rates Resale or republication not permitted without written consent of the publisherMar Ecol Prog Ser 280: [73][74][75][76][77][78][79][80][81][82][83] 2004 changes. Since the onset of industrialization in the 1880s, the health of the Florida Bay ecosystem has been negatively impacted on both decadal (e.g. increasing eutrophication) and centurial (e.g. changes in land use and water management practices within southern Florida) time-scales (Fourqurean & Robblee 1999). These anthropogenic changes have led to a significant alteration in freshwater flow patterns within the Everglades, causing declines in seagrass d...

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Section: Discussionsupporting

confidence: 52%

Evidence for dissolved organic nitrogen and phosphorus uptake during a cyanobacterial bloom in Florida Bay

Glibert¹,

Heil²,

Hollander³

et al. 2004

Mar. Ecol. Prog. Ser.

169

121

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“…In summer, community urea uptake rates range from 50 to 350 nmol urea-N l -1 h -1 (Sörenson & Sahlsten 1987, Berg et al 2001. Our enrichment cultures demonstrated that the estuarine bacterial populations had the potential to produce urea in this range (urea production from degradation of both adenine and guanine was 150 nmol urea-N l -1 h -1 ; Table 2).…”

Section: Production Of Ureamentioning

confidence: 84%

Purine and pyrimidine metabolism by estuarine bacteria

Berg

Jørgensen²

2006

Aquat. Microb. Ecol.

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Nucleotide bases are ubiquitous in living organisms, but the fate of these compounds in natural environments is poorly understood. Here we studied the metabolism of selected purines and pyrimidines in estuarine bacterial assemblages from the Øresund, Denmark. Depletion of nucleotide bases in the incubations was followed by the appearance of urea. The purine guanine and the catabolic intermediates hypoxanthine and xanthine were depleted 2 times faster from seawater incubations than the purine adenine, and 8 to 35 times faster than the pyrimidines thymine, cytosine, and uracil over the course of 141 h. After 48 h, 45 to 60% of guanine-N, hypoxanthine-N and xanthine-N was converted to urea-N while the conversion of adenine and pyrimidines to urea was slower, corresponding to 34% and 19 to 23%, respectively. After 96 h, urea concentrations declined in most of the incubations, indicating hydrolysis of urea by the bacterial populations. Bacterial metabolism of adenine in Øresund water was estimated to contribute up to 10% of the urea pool, but due to the efficient conversion of adenine, the ecosystem importance of adenine degradation to urea production was most likely greater. Growth of bacterial microcolonies on 0.2 µm pore-sized polycarbonate filters floating on natural seawater enriched with individual nucleotide bases varied significantly with substrate enrichment. Despite growth of only a small fraction of bacteria present in the natural assemblage on the filters, variation in bacterial microcolony biomass explained most of the variation in substrate utilization and urea production among the treatments. Our results suggest that bacterial catabolism of particularly purines and their intermediates, and to lesser extent pyrimidines, is a major process by which the N moiety of natural, heterocyclic bases are converted into urea which is easily assimilated.KEY WORDS: Purines · Pyrimidines · Urea production · Estuarine bacteria · Microcolony approach Resale or republication not permitted without written consent of the publisher

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“…in coastal upwelling. They prefer, and under some conditions physiologically require NO 3 over NH 4 (Syrett, 1981;Berg et al, 2001;Glibert et al, 2006). The model incorporates the concept of shift up, i.e.…”

Section: Model Development and Constructionmentioning

confidence: 99%

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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Variability in Inorganic and Organic Nitrogen Uptake Associated with Riverine Nutrient Input in the Gulf of Riga, Baltic Sea

Cited by 60 publications

References 78 publications

Evidence for dissolved organic nitrogen and phosphorus uptake during a cyanobacterial bloom in Florida Bay

Evidence for dissolved organic nitrogen and phosphorus uptake during a cyanobacterial bloom in Florida Bay

Purine and pyrimidine metabolism by estuarine bacteria

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

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