Organic nitrogen mineralization and substrate limitation of bacteria in Lake Michigan

Gardner, Wayne S.; Chandler, Joann F.; Laird, Gwenyth A.

doi:10.4319/lo.1989.34.2.0478

Cited by 31 publications

(26 citation statements)

References 25 publications

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“…Applying the average bacterial cell C content, determined from 1986 data, to bacterial sizes and concentrations determined in the July 1985 experiment yielded similar results: C consumption of 120, 132, 192, and 213 pg C liter-' from 5-, 28-, 70-, and 95-m water. Our overall results of decreasing LDOC concentration during summer-indicating that demand is greater than supply at that time-are consistent with another recent study from the same region in Lake Michigan which demonstrated that bacteria are more substrate limited in summer than in spring (Gardner et al 1989). Higher LDOC concentrations in the deep region from our study (Table 1, Fig.…”

Section: 1; Two-tailed T-test)supporting

confidence: 81%

Distribution of labile dissolved organic carbon in Lake Michigan

Laird

Scavia

1990

Limnology & Oceanography

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Bioassay‐measured, labile dissolved organic carbon (LDOC) concentrations were compared in near‐bottom and near‐surface Lake Michigan water between April and October 1986. In five of seven experiments, the LDOC concentration was higher in near‐bottom water. LDOC reached 40.2% of the total DOC pool in the near‐bottom water in late May and 13.8% in the near‐surface water in early July. Concentration in near‐bottom water was highest during early stratification; concentration in surface water varied less but was highest in early July. The data suggest that an allochthonous source of labile organic C may be important.

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Section: 1; Two-tailed T-test)supporting

confidence: 81%

Distribution of labile dissolved organic carbon in Lake Michigan

Laird

Scavia

1990

Limnology & Oceanography

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“…The dissolved nutrients being taken up metabolically from the solution by phytoplankton aggregate into organic particles, and organisms can be decomposed into inorganic nutrients through the mineralization process (Halemejko and Chrost 1984). However, the effects of the mineralization process are estimated to be small and it was generally not taken into consideration in the nutrient limitation bioassays (Bloesch et al 1977;Gao et al 2000Gao et al , 2006Gardner et al 1989;Kagami et al 2013;Kim et al 2006;Kolzau et al 2014). In this case, a particular nutrient could limit the growth of the phytoplankton once its concentration declined to a certain degree.…”

Section: Discussionmentioning

confidence: 99%

Critical nutrient thresholds needed to control eutrophication and synergistic interactions between phosphorus and different nitrogen sources

Zeng

Qin

Bao

et al. 2016

Environ Sci Pollut Res

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Eutrophication is one of the greatest threats to global freshwater ecosystems. The phytoplankton responses to nutrient inputs vary in different water bodies, so it is particularly important to determine the nutrient thresholds and synergistic interactions between nutrients in different freshwater ecosystems. Field sampling and bioassay experiments were conducted to determine the thresholds of soluble reactive phosphorus (SRP), nitrate-nitrogen (NO 3 -N), and ammonium-nitrogen (NH 4 -N) in Miyun Reservoir. A separate nutrient addition bioassay was designed to assess the synergistic interactions between these nutrients. Chlorophyll a (Chl a) concentrations were used to estimate phytoplankton biomass. The results showed the following: (1) nutrient threshold bioassay indicated that eutrophication thresholds of SRP, NO 3 -N, and NH 4 -N should be targeted at below 0.04 mg P L −1 , 0.5 mg N L −1 , and 0.3 mg N L −1 , respectively, to limit the growth of phytoplankton. (2) The stimulatory effect of BNH 4 -N plus P^on phytoplankton biomass was greater than (4) Ammonium was an important factor for the growth of phytoplankton and inputs of both NH 4 -N and NO 3 -N should be reduced to control bloom formation. Our findings imply that although P load reduction is important, appropriate reductions of all forms of N in watershed is recommended in the nutrient management strategy for Miyun Reservoir.

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“…For example, in the Mississippi River plume region, about 90% of the 'assimilated' I5N that had been added as labeled amino acids was recovered as 15NH4+ in bottle experiments with dark subsurface waters as compared to about 48% in surface waters under natural light . Similarly, organic substrate-depleted Lake Michigan bacteria regenerated an amount of ammonium approximately equivalent to the amount of added DFAA consumed (Gardner et al 1987(Gardner et al , 1989. Conversely, if other sources of labile carbon are available to be metabolized, more of the amino-N can be incorporated into biomass (see 'Results').…”

Section: Methodsmentioning

confidence: 99%

Effects of high-molecular-weight dissolved organic matter on nitrogen dynamics in the Mississippi River plume

Gardner¹,

Benner²,

Amon³

et al. 1996

Mar. Ecol. Prog. Ser.

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ABSTRACT-The dynamics of N and ~t s interactions with labile dlssol\ied organic C (DOC), bacteria, and phytoplankton were studied to determine potential effects of dissolved organlc matter (DOM) and light on N dynamics in surface waters of the Mississippi River (USA) plume in the Gulf of Mexico. Bacterial uptake of added labeled N compounds (INN.,+ or "N-labeled dissolved free amino acids. DFAA) was stimulated more by high-molecular-weight (HMW, > l kDa) DOM than by 101~-molecular-weight (LMW. < l kDa) DOM. An ~n d e x that ~nversely indicated the presence of labile DOC was defined as the fraction of assimilated Amino acid-l5B thdt was Recovered as "N-.Ammonium (ANRA), follo~vlng the additions of high-levels (4 pM) of "N-DFAA. ANRA ratios were high In the absence of other available carbon sources because heterotrophic bacteria were forced to use the added amino acids as a carbon source for respiration rather than as a nutrient source for biomass formation. In dynamic light/dark experiments, conducted with in situ populations of organisms, uptake rates of added 15NH4+ were significantly enhanced both by the presence of light and by the addition of HMW DOM. Uptake rates of added I5N-labeled DFAA were increased by the addition of HMW DOM but not by light. ANRA ratios were consistently lower in the presence of added HMM1 DOM than in controls. Added HMW DOM thus appeared to stimulate the incorporation of assimilated DFAA into bacterial biomass. Bacterial growth rates were relatively high in both light and dark bottles with DFAA additions and in light bottles with HMW DOM plus NH,' additions, but they remained comparatively low in dark bottles with added NH,' These results are consistent with the idea that bacterial N dynamics in these euphotic waters may be tightly coupled to photosynthetic activities over short time scales.

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Organic nitrogen mineralization and substrate limitation of bacteria in Lake Michigan

Cited by 31 publications

References 25 publications

Distribution of labile dissolved organic carbon in Lake Michigan

Distribution of labile dissolved organic carbon in Lake Michigan

Critical nutrient thresholds needed to control eutrophication and synergistic interactions between phosphorus and different nitrogen sources

Effects of high-molecular-weight dissolved organic matter on nitrogen dynamics in the Mississippi River plume

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