Abundance and diversity of diazotrophs in the surface sediments of Kongsfjorden, an Arctic fjord

Jabir, T.; Vipindas, Puthiya Veettil; Krishnan, K. P.; Hatha, A. A. Mohamed

doi:10.1007/s11274-020-02993-1

Cited by 13 publications

(6 citation statements)

References 72 publications

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“…They widely distribute in environments where active Fe (III) reduction takes place, such as rice paddies [56,57], wetlands [58], and landfill leachate-polluted aquifer [59]. Nitrogen fixation by Geobacteraceae has been detected in coastal sediments [60,61]. However, Geobacteraceae was seldom reported to comprise >50% of the nifH sequences obtained from coastal sediments over sulfate reducer, except in our study and Narragansett Bay sediments frequently stressed by seasonal hypoxia [62].…”

Section: Iron-reducing Bacteria Contributed Primarily To Benthic Nitr...mentioning

confidence: 50%

Seasonal Hypoxia Enhances Benthic Nitrogen Fixation and Shapes Specific Diazotrophic Community in the Eutrophic Marine Ranch

et al. 2023

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Recently, a growing number of studies have confirmed that biological nitrogen fixation is also an important reactive nitrogen source in coastal regions. However, how benthic nitrogen fixation and diazotrophic community in coastal regions respond to seasonal hypoxia remains largely unknown. In this study, we investigated the spatiotemporal pattern of potential nitrogen fixation rate and diazotrophic abundance and community in sediments of a eutrophic marine ranch experiencing summer hypoxia using 15N tracing and high throughput sequencing techniques. The results showed that potential nitrogen fixation rates ranged from 0.013 to 10.199 μmol kg−1 h−1, and were significantly enhanced by summer hypoxia (ANOVA, p < 0.05). However, nifH gene abundance peaked in June. The diazotrophic community was dominated by Geobacteraceae (>60%), followed by Desulfobulbaceae (13.61%). Bottom water oxygen, pH, Chl-a concentration, and sediment NH4+ significantly regulated benthic nitrogen fixation, while the variation of diazotrophic community was explained by sediment TOC, TN, and Fe content (p < 0.05). This study highlighted that hypoxia stimulated benthic nitrogen fixation, which counteracted the nitrogen removal by denitrification and anammox, and could further aggregate eutrophication of the coastal marine ranch. Moreover, the result emphasized the importance of nitrogen fixation in coastal regions for the global N budget.

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Section: Iron-reducing Bacteria Contributed Primarily To Benthic Nitr...mentioning

confidence: 50%

Seasonal Hypoxia Enhances Benthic Nitrogen Fixation and Shapes Specific Diazotrophic Community in the Eutrophic Marine Ranch

et al. 2023

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“…The remaining six Arctic diazotrophs may represent new species within genera Arcobacter , Sunxiuqinia , Psychromonas , Oceanobacter , Immunodisolibacter , Novosphingobium (Table 1 and Supplementary Table S3 ). Thus far, nifH of Arcobacter has been found in oceans around the globe including the Arctic Ocean [ 11 , 47 , 48 ], and nifH of Novosphingobium was recently detected in deep waters in the subtropical ocean [ 49 ]. The diazotrophs within genera Sunxiuqinia , Psychromonas , Oceanobacter , and Immunodisolibacter were newly discovered in this study.…”

Section: Resultsmentioning

confidence: 99%

Distribution and survival strategies of endemic and cosmopolitan diazotrophs in the Arctic Ocean

et al. 2023

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Dinitrogen (N2) fixation is the major source of reactive nitrogen in the ocean and has been considered to occur specifically in low-latitude oligotrophic oceans. Recent studies have shown that N2 fixation also occurs in the polar regions and thus is a global process, although the physiological and ecological characteristics of polar diazotrophs are not yet known. Here, we successfully reconstructed diazotroph genomes, including that of cyanobacterium UCYN-A (Candidatus ‘Atelocyanobacterium thalassa’), from metagenome data corresponding to 111 samples isolated from the Arctic Ocean. These diazotrophs were highly abundant in the Arctic Ocean (max., 1.28% of the total microbial community), suggesting that they have important roles in the Arctic ecosystem and biogeochemical cycles. Further, we show that diazotrophs within genera Arcobacter, Psychromonas, and Oceanobacter are prevalent in the <0.2 µm fraction in the Arctic Ocean, indicating that current methods cannot capture their N2 fixation. Diazotrophs in the Arctic Ocean were either Arctic-endemic or cosmopolitan species from their global distribution patterns. Arctic-endemic diazotrophs, including Arctic UCYN-A, were similar to low-latitude-endemic and cosmopolitan diazotrophs in genome-wide function, however, they had unique gene sets (e.g., diverse aromatics degradation genes), suggesting adaptations to Arctic-specific conditions. Cosmopolitan diazotrophs were generally non-cyanobacteria and commonly had the gene that encodes the cold-inducible RNA chaperone, which presumably makes their survival possible even in deep, cold waters of global ocean and polar surface waters. This study shows global distribution pattern of diazotrophs with their genomes and provides clues to answering the question of how diazotrophs can inhabit polar waters.

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“…This finding might imply that the molar content of N release was higher than P release from sediment to water in the low water level phase, and the molar content increasing of sediment N was higher than sediment P in the high water level phase. It has been previously reported that environmental factors play an important role in structuring the diazotrophic community (Weber et al, 2017;Luo et al, 2021;Jabir et al, 2021a;Tian et al, 2021a;Jabir et al, 2021b). Results of RDA indicated that TN and TP were the most significant variables explaining the variation of the diazotrophic community composition (Figure 7).…”

Section: Environmental Factors Regulating Diazotrophic Community Comp...mentioning

confidence: 63%

“…As mentioned above, WLFs can regulate the release of sediment nutrients in floodplain lakes, and in turn change the nutrient content. Nutrient availability can shape the diazotrophic community in aquatic ecosystems (Weber et al, 2017;Wang et al, 2020;Luo et al, 2021;Tian et al, 2021a;Jabir et al, 2021b). Therefore, elucidating the response of the sediment diazotrophic community to WLFs is of great interest and importance to gain insights into the ecological impacts of WLFs and the nitrogen-cycling processes of the floodplain lake.…”

Section: Introductionmentioning

confidence: 99%

Diazotrophic community in the sediments of Poyang Lake in response to water level fluctuations

Wu,

Wang,

Chen

et al. 2024

Front. Microbiol.

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Water level fluctuations (WLFs) are typical characteristic of floodplain lakes and dominant forces regulating the structure and function of lacustrine ecosystems. The sediment diazotrophs play important roles in contributing bioavailable nitrogen to the aquatic environment. However, the relationship between the diazotrophic community and WLFs in floodplain lakes is unknown. In this paper, we carried out a comprehensive investigation on the alpha diversity, abundance, composition and co-occurrence network of the sediment diazotrophs during different water level phases in Poyang Lake. There were no regular variation patterns in the alpha diversity and abundance of the sediment diazotrophs with the water level phase transitions. The relative abundance of some diazotrophic phyla (including Alphaproteobacteria, Deltaproteobacteri, Euryarchaeota, and Firmicutes) and genera (including Geobacter, Deferrisoma, Desulfuromonas, Rivicola, Paraburkholderia, Methylophilus, Methanothrix, Methanobacterium, and Clostridium) was found to change with the water level phase transitions. The results of ANOSIM, PerMANOVA, and DCA at the OTU level showed that the diazotrophic community structure in the low water level phase was significantly different from that in the two high water level phases, while there was no significant difference between the two high water level phases. These results indicated that the diazotrophic community was affected by the declining water level in terms of the composition, while the rising water level contributed to the recoveries of the diazotrophic community. The diazotrophs co-occurrence network was disrupted by the declining water level, but it was strengthened by the rising water level. Moreover, redundancy analysis showed that the variation of the diazotrophic community composition was mostly related to sediment total nitrogen (TN) and total phosphorous (TP). Interestingly, the levels of sediment TN and TP were also found to vary with the water level phase transitions. Therefore, it might be speculated that the WLFs may influence the sediment TN and TP, and in turn influence the diazotrophic community composition. These data can contribute to broadening our understanding of the ecological impacts of WLFs and the nitrogen fixation process in floodplain lakes.

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Abundance and diversity of diazotrophs in the surface sediments of Kongsfjorden, an Arctic fjord

Cited by 13 publications

References 72 publications

Seasonal Hypoxia Enhances Benthic Nitrogen Fixation and Shapes Specific Diazotrophic Community in the Eutrophic Marine Ranch

Seasonal Hypoxia Enhances Benthic Nitrogen Fixation and Shapes Specific Diazotrophic Community in the Eutrophic Marine Ranch

Distribution and survival strategies of endemic and cosmopolitan diazotrophs in the Arctic Ocean

Diazotrophic community in the sediments of Poyang Lake in response to water level fluctuations

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