Nitrogen fixation by Baltic cyanobacteria is adapted to the prevailing photon flux density

Evans, A. M.; Gallon, John; Jones, Alwyn; Staal, Marc; Stal, LJ; Villbrandt, Marlies; Walton, Terence J.

doi:10.1046/j.1469-8137.2000.00696.x

Cited by 27 publications

(22 citation statements)

References 45 publications

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“…A linear rise was determined in Kana (1993) ) was not sufficient to significantly increase N 2 fixation in Trichodesmium (Table 2). However, the N 2 fixation rates of Nodularia spumigena increased significantly when the cells were exposed to higher light intensities in the present study (Table 2), a result in accordance with Evans et al (2000, their Fig. 7b), who used light intensities up to 400 µmol quanta m -2 s -1 .…”

Section: Fluctuation In Cellular Light Energy Supplysupporting

confidence: 92%

Release of fixed N2 and C as dissolved compounds by Trichodesmium erythreum and Nodularia spumigena under the influence of high light and high nutrient (P)

Wannicke¹,

Koch²,

Voß³

2009

Aquat. Microb. Ecol.

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Diel variations of N 2 and C fixation rates, as well as subsequent release of total dissolved N (TDN) and dissolved organic carbon (DOC) were determined for Trichodemsium erythreum and Nodularia spumigena. A circadian rhythm of N 2 and C fixation, as well as a periodicity in the calculated release of dissolved compounds, was observed. From the amounts of N and inorganic C fixed by T. erythreum during the light period of the experiment, 71 and 50% were released as TDN and DOC, respectively; for N. spumigena we found a release of 89 and 53%, respectively, during the light period. Additionally, 2 controlling factors (light and nutrient concentrations) for the release of TDN and DOC were studied. The data suggest that rapid shifts towards higher light intensity lead to a pronounced exudation of TDN and DOC. On a short-term basis (first 30 min after exposure), the exudation of NH 4 + and DON consumed up to 52% of electrons harvested by the cells in the same time interval. Thus TDN release serves as a potential electron sink and protects cells from photodestruction. On the other hand, there was no clear effect of phosphorus concentration on the release of TDN and DOC. Our results indicate that uptake and subsequent exudation of TDN and DOC might be induced by abiotic parameters, besides being regulated endogenously by multiple feedback loops.

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Section: Fluctuation In Cellular Light Energy Supplysupporting

confidence: 92%

Release of fixed N2 and C as dissolved compounds by Trichodesmium erythreum and Nodularia spumigena under the influence of high light and high nutrient (P)

Wannicke¹,

Koch²,

Voß³

2009

Aquat. Microb. Ecol.

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“…and Nodularia sp. corresponded well with earlier observations of NA patterns for these organisms (Evans et al 2000, Stal et al 2003. At Stn II in 2006, the cell-specific nifH expression <1 transcript copy -1 can be explained by the fact that in heterocystous Cyanobacteria only a fraction of the cells, namely those that differentiate to heterocysts, transcribe nifH.…”

Section: Cell-specific Gene Expressionsupporting

confidence: 90%

Temporal and spatial variability of nifH expression in three filamentous Cyanobacteria in coastal microbial mats

Severin¹,

Stal²

2010

Aquat. Microb. Ecol.

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Cyanobacteria are often the most conspicuous structural part of microbial mats. They are also the only oxygenic phototrophs capable of N 2 fixation (diazotrophy). This represents an important advantage for persistence in the often N-depleted marine intertidal microbial mats. In this study the daily pattern of expression of the structural gene for dinitrogenase reductase, nifH and the 16S rRNA gene of 3 benthic filamentous diazotrophic Cyanobacteria (Lyngbya sp., Nodularia sp. and Anabaena sp.) was measured by using quantitative RT-PCR. Gene expression patterns were compared and related to the daily pattern of nitrogenase activity. Microscopic observations revealed that the non-heterocystous Lyngbya sp. was the major cyanobacterial morphotype in all the microbial mats studied. When normalized to copy number, nifH as well as 16S rRNA gene expression by Lyngbya sp. was higher than by the heterocystous Cyanobacteria in all but one mat type. Related to the total amount of extracted RNA, Lyngbya sp. dominated 16S rRNA gene expression as well but was outcompeted by the heterocystous Cyanobacteria with respect to total nifH expression. This was due to the low DNA copy number of Lyngbya sp. nifH. The results revealed different cell-specific expression levels and varying contribution to the overall nifH and 16S rRNA gene expression by the 3 Cyanobacteria over the course of a daily cycle as well as in the different mat types. With respect to the overall nifH expression, the structurally dominant diazotroph was not the most active. Moreover, nifH expression pattern did not follow nitrogenase activity.

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“…In contrast, the nitrogen fixation activity (nitrogenase activity and N 2 uptake) in the Porcelana hot spring showed a positive correlation with nifH gene expression. Moreover, because nitrogen fixation during the daytime is typical for eco systems dominated by heterocystous cyanobacteria (Stal, 1995;Evans et al, 2000;Charpy et al, 2007;Bauer et al, 2008), our data infer the predominance, if not the exclusive role, of the heterocystous Mastigocladus-type cyanobacteria in nitrogen fixation in the Porcelana hot spring.…”

Section: Discussionmentioning

confidence: 65%

The cyanobacterium Mastigocladus fulfills the nitrogen demand of a terrestrial hot spring microbial mat

et al. 2015

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Research (CR)2, Santiago, ChileCyanobacteria from Subsection V (Stigonematales) are important components of microbial mats in non-acidic terrestrial hot springs. Despite their diazotrophic nature (N 2 fixers), their impact on the nitrogen cycle in such extreme ecosystems remains unknown. Here, we surveyed the identity and activity of diazotrophic cyanobacteria in the neutral hot spring of Porcelana (Northern Patagonia, Chile) during 2009 and 2011-2013. We used 16S rRNA and the nifH gene to analyze the distribution and diversity of diazotrophic cyanobacteria. Our results demonstrate the dominance of the heterocystous genus Mastigocladus (Stigonematales) along the entire temperature gradient of the hot spring (69-38°C). In situ nitrogenase activity (acetylene reduction), nitrogen fixation rates (cellular uptake of 15 N 2 ) and nifH transcription levels in the microbial mats showed that nitrogen fixation and nifH mRNA expression were light-dependent. Nitrogen fixation activities were detected at temperatures ranging from 58°C to 46°C, with maximum daily rates of 600 nmol C 2 H 4 cm − 2 per day and 94.1 nmol N cm − 2 per day. These activity patterns strongly suggest a heterocystous cyanobacterial origin and reveal a correlation between nitrogenase activity and nifH gene expression during diurnal cycles in thermal microbial mats. N and C fixation in the mats contributed~3 g N m − 2 per year and 27 g C m − 2 per year, suggesting that these vital demands are fully met by the diazotrophic and photoautotrophic capacities of the cyanobacteria in the Porcelana hot spring.

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Nitrogen fixation by Baltic cyanobacteria is adapted to the prevailing photon flux density

Cited by 27 publications

References 45 publications

Release of fixed N2 and C as dissolved compounds by Trichodesmium erythreum and Nodularia spumigena under the influence of high light and high nutrient (P)

Release of fixed N2 and C as dissolved compounds by Trichodesmium erythreum and Nodularia spumigena under the influence of high light and high nutrient (P)

Temporal and spatial variability of nifH expression in three filamentous Cyanobacteria in coastal microbial mats

The cyanobacterium Mastigocladus fulfills the nitrogen demand of a terrestrial hot spring microbial mat

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