Bacterial biomass production and ammonium regeneration in Mediterranean sea water supplemented with amino acids. 2. Nitrogen flux through heterotrophic microplankton food chain

Wambeke, F. Van; Bianchi, Micheline

doi:10.3354/meps023117

Cited by 20 publications

(11 citation statements)

References 23 publications

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“…In January, bacterial growth (72 h) was immediately followed by a micro-predator increase (Wambeke & Bianchi 1985). Considering the organic eutrophication of our experimental system, lack of mineral nutrients and predation account for the low maximum numbers of bacteria observed.…”

Section: Discussionmentioning

confidence: 99%

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Bacterial biomass production and ammonium regeneration in Mediterranean sea water supplemented with amino acids. 1. Correlations between bacterial biomass, bacterial activities and environmental parameters

Wambeke¹,

Bianchi²

1985

Mar. Ecol. Prog. Ser.

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Batch systems were used to establish the nitrogen balance of a marine coastal water in order to quantify bacterial responses to organic nitrogen (amino acid) enrichment in summer and winter. During both seasons, the amino-acid enriched batch clearly showed 'sollicitation' and 'growth' phases in bacterial communities. Maximum growth rates were 0.38 h-' at 25°C and 0.07 h-' at 10°C in summer and winter experiments as estimated from direct counts. Short sampling time (1 h) and parameters (direct counts, plate counts, biovolumes measurements. ATP, chlorophyll, mineral salts, 14C uptake, mineralization) describing bacterial growth and activity were used. Parameter associations determined via principal component analysis, discarding the problem of quantity with standardized variables, showed analogous responses in the blank and in enriched batches in summer. High mineralization rates of carbon (40 '10) and nitrogen (regeneration ratio 0.65 in Jun, 0.5 in Jan) were observed in conditions of substrate excess.

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Section: Discussionmentioning

confidence: 99%

“…The influence of prey-predator interactions, limiting bacterial numbers 3 to 10 d after initial enrichment in January, is not taken in account here, but will be considered in the second paper (Van Wambeke & Bianchi 1985).…”

Section: Introductionmentioning

confidence: 99%

Bacterial biomass production and ammonium regeneration in Mediterranean sea water supplemented with amino acids. 1. Correlations between bacterial biomass, bacterial activities and environmental parameters

Wambeke¹,

Bianchi²

1985

Mar. Ecol. Prog. Ser.

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“…If we consider the grazer population (4 ml-') to produce 2.2 x 1O-8 pg-atoms N grazer-' h-* (Van Wambeke and Bianchi 1985), its contribution would be < 1% of the total NH,+ produced. The production of NH,+ by microscopically unobservable grazers (Fuhrman and McManus 1984) may be possible, but we also regard this as minor.…”

Section: Discussionmentioning

confidence: 99%

Amino acid and ammonium utilization by heterotrophic marine bacteria grown in enriched seawater

Tupas

Koike

1990

Limnology & Oceanography

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The nitrogen metabolism of natural bacterial assemblages was studied in seawater cultures enriched with the dissolved materials released by the mussel Myths edulis. The mussel released dissolved organic C, NH,', and dissolved organic N (DON), mostly in the form of combined amino acids (-70-100%) that constituted 30% of the total N released. lsNH4+ techniques showed that the contribution of NH,+ to total microbial N demand during growth ranged from 50 to 88% even when large amounts of DON were utilized (-70-260% of total bacterial N produced). An average of 80% of the DON used was converted to NH,+, showing simultaneous assimilation and regeneration of NH,+ by the natural microbial population and contradicting the idea that NH,' assimilation occurs only when organic N is limiting.

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“…From recent studies, however, it is now abundantly clear that both cdiates and phagotrophic rnicroflagellates regenerate NH: in large quantities while grazing (Gast & Horstmann 1983, Sherr et al 1983, Anders-son et al 1985, Van Wambeke & Bianchi 1985. In fact, reported weight-specific rates of NH: regeneration from the few studies on marine microflagellates are considerably higher than those for most macrozooplankton .…”

Section: Introductionmentioning

confidence: 99%

Nutrient cycling in a microflagellate food chain: III. Phosphorus dynamics

Andersen¹,

Goldman²,

Caron³

et al. 1986

Mar. Ecol. Prog. Ser.

100

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As part of a series of grazing experiments in batch cultures, we found that the phagotrophlc microflagellate Paraphysomonas imperforata, while grazing on the diatom Phaeodactylum tn'cornutum or bacteria, was responsible for the bulk of phosphorus regeneration. Regeneration of soluble reactive phosphorus (SRP) and dissolved organic phosphorus (DOP) was negligible in control cultures of the diatom alone, bacteria alone, or the 2 microbes together. When the m~croflagellate grazed on prey organisms that had been precultured with excess nutrients or under nitrogen limitation there was considerable regeneration of total dissolved phosphorus (TDP = SRP + DOP). Rates of TDP regeneration were greatest during exponential growth of the microflagellate and then decreased through the transition and stationary phases. Overall, up to 70 % of the phosphorus initially incorporated into prey biomass was regenerated through the stationary phase. Total excretion of DOP was about 15 to 20% of TDP, although DOP excretion made up a larger fraction of total phosphorus excretion for short periods during the exponential phase of growth. When the prey were phosphoruslimited virtually no TDP was excreted throughout the entire growth cycle of the microflagellate. Our results indicate that Protozoa have higher weight-specific rates of phosphorus excretion than do Metazoa. Although metabolic activity is not the sole indicator of the role Protozoa play in the nutrient regeneration process, our results, together with those from size-fractionation studies on nutrient regeneration, point toward a major role for Protozoa in pelagic waters where they constitute a large fraction of the zooplankton biomass.

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Bacterial biomass production and ammonium regeneration in Mediterranean sea water supplemented with amino acids. 2. Nitrogen flux through heterotrophic microplankton food chain

Abstract: Nitrogen dynamics effected by bacteria and bacterivorous microflagellates were investigated in a 3501 batch experiment. In conditions favouring heterotroph activity (initial amino-acid enrichment 100 pg-at N1-l) mineralization rates were respectively 2.7 and 10 pg-at N-NH,+ 1 -I

Cited by 20 publications

References 23 publications

Bacterial biomass production and ammonium regeneration in Mediterranean sea water supplemented with amino acids. 1. Correlations between bacterial biomass, bacterial activities and environmental parameters

Bacterial biomass production and ammonium regeneration in Mediterranean sea water supplemented with amino acids. 1. Correlations between bacterial biomass, bacterial activities and environmental parameters

Amino acid and ammonium utilization by heterotrophic marine bacteria grown in enriched seawater

Nutrient cycling in a microflagellate food chain: III. Phosphorus dynamics

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