Urea and DON uptake by a Lyngbya gracialis dominated microbial mat: a controlled laboratory experiment

Rondell, Jane B.; Finster, Kai; Lomstein, Bente Aa.

doi:10.3354/ame021169

Cited by 17 publications

(17 citation statements)

References 19 publications

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“…Microalgae (cyanobacteria) can survive with only urea as a N source and are capable of uptake in both the light and dark, with somewhat reduced uptake in the dark (Rondell et al 2000). The capacity for dark uptake may explain why we did not observe light-dark differences in sediment fluxes, and precludes a distinct conclusion that microalgae prevent urea fluxes to the water column.…”

Section: Sediment Fluxes and The Influence Of Benthic Microalgaethe Dcontrasting

confidence: 42%

“…The correlation between the DO efflux and DON influx, although not as clear across sites as for DIN, suggests a temporal importance of microalgal DON uptake consistent with Rondell et al (2000), who showed utilization of small DON compounds by microbial mat communities dominated by cyanobacteria. Additionally, microalgal DO production may stimulate uptake of dissolved organic compounds by sediment heterotrophs.…”

Section: Sediment Fluxes and The Influence Of Benthic Microalgaethe Dmentioning

confidence: 87%

“…For example, bioavailable compounds such as amino acids and urea may make up a significant portion of the DON pool and contribute to the benthic flux of DON (Boucher and Boucher-Rodoni 1988;Lomstein et al 1989;Burdige and Zheng 1998). In addition, these small, labile organic compounds may represent an important source of N for both heterotrophic and autotrophic microorganisms, as well as for benthic plants (Jorgensen 1982;Admiraal et al 1984;Lomstein et al 1989;Keil and Kirchman 1993;Nilsson and Sundback 1996;Rondell et al 2000). In the work presented here, we investigated the role of the two dominant groups of benthic primary producers, macroalgae and microalgae, in regulating sedimentwater column exchanges of DIN, bulk DON, and specific labile DON compounds (dissolved free and combined amino acids [DFAA, DCAA], urea) in Hog Island Bay, a shallow lagoon on the Virginia coast.…”

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confidence: 99%

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Benthic algae control sediment—water column fluxes of organic and inorganic nitrogen compounds in a temperate lagoon

Tyler

McGlathery

Anderson

2003

Limnology & Oceanography

144

101

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Coastal lagoons are a common land-margin feature worldwide and function as an important filter for nutrients entering from the watershed. The shallow nature of lagoons leads to dominance by benthic autotrophs, which can regulate benthic-pelagic coupling. Here we demonstrate that both microalgae and macroalgae are important in controlling dissolved inorganic as well as organic nitrogen (DIN and DON) fluxes between the sediments and the water column. Fluxes of nitrogen (NH , NO , DON, urea, and dissolved free and combined amino acids [DFAA,DCAA]) and O 2 were measured from October 1998 through August 1999 in sediment cores collected from Hog Island Bay, Virginia. Cores were collected from four sites representing the range of environmental conditions across this shallow lagoon: muddy, high-nutrient and sandy, low-nutrient sites that were both dominated by benthic microalgae, and a mid-lagoon site with fine sands covered by dense macroalgal mats. Sediment-water column DON fluxes were highly variable and comparable in magnitude to DIN fluxes; fluxes of individual compounds (urea, DFAA, DCAA) often proceeded simultaneously in different directions. Where sediment metabolism was net autotrophic because of microalgal activity, TDN (total dissolved nitrogen) fluxes, mostly comprised of DIN, urea, and DFAA, were directed into the sediments. Heterotrophic sediments, including those underlying macroalgal mats, were a net source of TDN, mostly as DIN. Macroalgae intercepted sediment-water column fluxes of DIN, urea, and DFAA, which accounted for 27-75% of calculated N demand. DON uptake was important in satisfying macroalgal N demand seasonally and where DIN concentrations were low. Up to 22% of total N uptake was released to the water column as DCAA. Overall, macroalgae assimilated, transformed, and rereleased to the water column both organic and inorganic N on short (minutes-hours) and long (months) time scales. Microalgae and macroalgae clearly regulate benthic-pelagic coupling and thereby influence transformations and retention of N moving across the land-sea interface.

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Section: Sediment Fluxes and The Influence Of Benthic Microalgaethe Dcontrasting

confidence: 42%

Section: Sediment Fluxes and The Influence Of Benthic Microalgaethe Dmentioning

confidence: 87%

mentioning

confidence: 99%

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Benthic algae control sediment—water column fluxes of organic and inorganic nitrogen compounds in a temperate lagoon

Tyler

McGlathery

Anderson

2003

Limnology & Oceanography

144

101

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“…Despite the importance of benthic DON fluxes, these have only been measured in a few studies of shallow coastal waters (e.g. Burdige & Zheng 1998 and references therein;Rondell et al 2000). The robustness of the denitrification efficiency relationship (Fig.…”

Section: Denitrification Efficiencymentioning

confidence: 99%

Comparison of carbon production and decomposition, benthic nutrient fluxes and denitrification in seagrass, phytoplankton, benthic microalgae- and macroalgae-dominated warm-temperate Australian lagoons

Eyre¹,

Ferguson²

2002

Mar. Ecol. Prog. Ser.

232

207

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“…Benthic microalgal species have been found to take up labile DON fractions, such as urea and DFAA (Admiraal et al 1987, Rondell et al 2000, Tuchman et. al 2006.…”

Section: Abstract: Microphytobenthos · Nitrogen · Don · Urea · Aminomentioning

confidence: 99%

Dissolved organic nitrogen: an important source of nitrogen for the microphytobenthos in sandy sediment

Sundbäck¹,

Lindehoff²,

Granéli³

2011

Aquat. Microb. Ecol.

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To test the hypothesis that dissolved organic nitrogen (DON) is important for sustaining primary production by the microphytobenthos (MPB) in nitrogen-limited conditions, we measured the uptake of 15 N-labelled urea, the amino acids glycine (GLY) and glutamic acid (GLU), and nitrate and ammonium under simulated in situ light and temperature conditions. Microphytobenthic primary production and chlorophyll a (chl a) were also measured. The MPB was dominated by diatoms attached to sand grains, with cyanobacteria making up ~30% of the biomass. Activities of the hydrolytic ectoenzymes leucine aminopeptidase (AMA), alkaline phosphatase (APA) and β-glucosidase (GLA) in filter-fractionated sediment showed that the microbenthic community was strongly deficient in nitrogen (N), with the bacterial fraction (<1 μm) also limited in phosphorus. Uptake of DON (urea + GLU + GLY) accounted for ~50 to 65% of the uptake of 15 N-labelled substrates, with a higher proportion of DON uptake at low substrate concentrations (≤2 μM). Except for nitrate, the kinetics fitted a linear model. The calculated relative preference index (RPI), based on pore water concentrations, suggested that the order of preference of the microbenthic community was NH 4 + > urea > GLU > NO 3 -> GLY. Using a prokaryotic inhibitor (chloramphenicol), and theoretical calculations of algal uptake based on C:chl a ratios, it was estimated that the 'algal' uptake of nitrogen accounted for ~55 to 90% of DON uptake. Uptake rates were, however, estimated to cover only 26 to 50% of the nitrogen demand of the MPB, suggesting that pore water concentrations of nitrogen were not sufficient to meet the microalgal demand in early summer and that, in sandy sediments of microtidal waters, the MPB may often be severely limited in nitrogen. KEY WORDS: Microphytobenthos · Nitrogen · DON · Urea · Amino acids · EctoenzymesResale or republication not permitted without written consent of the publisher Aquat Microb Ecol 63: 89-100, 2011 As is the case for tropical sandy areas, which are extremely limited in nitrogen (Eyre et al. 2008), a strong influence of the MPB on benthic turnover of nitrogen also appears to apply to sandy sediments in cool nitrogen-poor microtidal areas , Engelsen et al. 2008. Although microalgae are apparently N-limited in such sediments, the MPB biomass and primary production are often as high -or even higher -than in relatively nutrient-rich silty sediments , Engelsen et al. 2008. This is also the case for sandy sediments on tidal coasts (Barranguet et al. 1998, Billerbeck et al. 2007). Explanations for a higher algal activity in sandy sediments include better light penetration and more effective transport of solute to the algae, particularly in permeable intertidal inundated sediments (Billerbeck et al. 2007). An additional explanation is that N is efficiently recycled within the microbial communities of the sediment surface (Lomstein et al. 1998, Cook et al. 2007, Gribsholt et al. 2009), sustaining productivity by using available 'old nitrogen'. ...

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Urea and DON uptake by a Lyngbya gracialis dominated microbial mat: a controlled laboratory experiment

Cited by 17 publications

References 19 publications

Benthic algae control sediment—water column fluxes of organic and inorganic nitrogen compounds in a temperate lagoon

Benthic algae control sediment—water column fluxes of organic and inorganic nitrogen compounds in a temperate lagoon

Comparison of carbon production and decomposition, benthic nutrient fluxes and denitrification in seagrass, phytoplankton, benthic microalgae- and macroalgae-dominated warm-temperate Australian lagoons

Dissolved organic nitrogen: an important source of nitrogen for the microphytobenthos in sandy sediment

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