Aquatic heterotrophic bacteria have highly flexible phosphorus content and biomass stoichiometry

Godwin, Casey M.; Cotner, James B.

doi:10.1038/ismej.2015.34

Cited by 83 publications

(64 citation statements)

References 24 publications

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“…This size‐based prediction is supported by widespread empirical evidence for high levels and flexibility of elemental stoichiometry in heterotrophic bacteria (Chrzanowski and Grover ; Cotner et al. ; Godwin and Cotner ; Makino et al. ), and the cyanobacterial Synechococcus (Garcia et al.…”

Section: Discussionmentioning

confidence: 72%

Single Cell Analysis Linking Ribosomal (r)DNA and rRNA Copy Numbers to Cell Size and Growth Rate Provides Insights into Molecular Protistan Ecology

Gong

2017

J Eukaryotic Microbiology

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Ribosomal (r)RNA and rDNA have been golden molecular markers in microbial ecology. However, it remains poorly understood how ribotype copy number (CN)‐based characteristics are linked with diversity, abundance, and activity of protist populations and communities observed at organismal levels. Here, we applied a single‐cell approach to quantify ribotype CNs in two ciliate species reared at different temperatures. We found that in actively growing cells, the per‐cell rDNA and rRNA CNs scaled with cell volume (CV) to 0.44 and 0.58 powers, respectively. The modeled rDNA and rRNA concentrations thus appear to be much higher in smaller than in larger cells. The observed rRNA:rDNA ratio scaled with CV 0.14. The maximum growth rate could be well predicted by a combination of per‐cell ribotype CN and temperature. Our empirical data and modeling on single‐cell ribotype scaling are in agreement with both the metabolic theory of ecology and the growth rate hypothesis, providing a quantitative framework for linking cellular rDNA and rRNA CNs with body size, growth (activity), and biomass stoichiometry. This study also demonstrates that the expression rate of rRNA genes is constrained by cell size, and favors biomass rather than abundance‐based interpretation of quantitative ribotype data in population and community ecology of protists.

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Section: Discussionmentioning

confidence: 72%

Single Cell Analysis Linking Ribosomal (r)DNA and rRNA Copy Numbers to Cell Size and Growth Rate Provides Insights into Molecular Protistan Ecology

Gong

2017

J Eukaryotic Microbiology

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“…Relative % BDOP also showed a much larger range of values compared to relative %BDOC. 2010), while individual strains can have highly variable biomass composition with values well over 1000:1 (Godwin and James, 2015). Therefore, the stoichiometry of the bioavailable nutrients measured in this study more closely match typical bacterial biomass stoichiometry than measures of bulk nutrient chemistry.…”

Section: Stoichiometry Of Bioavailable Nutrientsmentioning

confidence: 81%

Bioavailability of Dissolved Organic Phosphorus in Temperate Lakes

Thompson

Cotner

2018

Front. Environ. Sci.

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Freshwater aquatic systems are biogeochemical hotspots, with heterotrophic bacteria rapidly cycling the compounds that pass through them. P is a key nutrient that controls primary production in many freshwater ecosystems and is important for understanding eutrophication in lakes. Previous work has often focused on the dynamics of inorganic phosphorus and its impact on primary production, however, the role of nutrients bound in more complex organic forms (such as dissolved organic phosphorus, DOP) in supporting primary production and harmful algal blooms has been neglected. Here, we quantify the bioavailability of dissolved organic carbon (DOC) and DOP in 27 aquatic systems across the Upper Midwest United States. Using exponential decay models, long-term nutrient degradation assays revealed that decay constants for DOP ranged from −0.001 per day to −0.12 per day with a median value of −0.01 per day. These rates were geographically variable and were as high or higher than DOC decay constants, which ranged from −0.003 per day to −0.024 per day with a median value of −0.01 per day. Additionally, total bioavailability of DOP ranged from 0 to 100% with a median value of 78% of the DOP pool, demonstrating that DOP bioavailability was highly variable across systems. In contrast, bioavailable DOC was more tightly constrained with values ranging from 4.37 to 53.81% of the total DOC pool with a median value of 24.95%. DOP bioavailability was negatively correlated with the DOC:DOP of the organic matter pool, suggesting that bioavailable DOP is drawn down in systems that are more likely to be P limited. Finally, we show that including estimates of DOC and DOP bioavailability reduces estimates of elemental imbalance experienced by aquatic bacteria.

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“…The observed chl-a increase is somewhat lower, ∼30 ng chl-a l −1 . However, the highest bacterial production rate was ∼3.3 nmol C l −1 h −1 , at 24 h after addition, which corresponds to ∼1.6 nmol P l −1 d −1 , using a C/P ratio of 50 for bacteria (Fagerbakke et al, 1996), although the latter is not constant (Zimmerman et al, 2014;Godwin and Cotner, 2015). Assuming that out of the released phosphate ∼ 1.6 nM was used by the bacteria and 2.2 nM was used by the autotrophs, the latter corresponds to the observed increase in chl-a (∼30 ng l −1 ).…”

Section: Discussionmentioning

confidence: 99%

The Potential Impact of Saharan Dust and Polluted Aerosols on Microbial Populations in the East Mediterranean Sea, an Overview of a Mesocosm Experimental Approach

et al. 2016

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Recent estimates of nutrient budgets for the Eastern Mediterranean Sea (EMS) indicate that atmospheric aerosols play a significant role as suppliers of macro-and micro-nutrients to its Low Nutrient Low Chlorophyll water. Here we present the first mesocosm experimental study that examines the overall response of the oligotrophic EMS surface mixed layer (Cretan Sea, May 2012) to two different types of natural aerosol additions, "pure" Saharan dust (SD, 1.6 mg l −1 ) and mixed aerosols (A-polluted and desert origin, 1 mg l −1 ). We describe the rationale, the experimental set-up, the chemical characteristics of the ambient water and aerosols and the relative maximal biological impacts that resulted from the added aerosols. The two treatments, run in triplicates (3 m 3 each), were compared to control-unamended runs. Leaching of ∼2.1-2.8 and 2.2-3.7 nmol PO 4 and 20-26 and 53-55 nmol NO x was measured per each milligram of SD and A, respectively, representing an addition of ∼30% of the ambient phosphate concentrations. The nitrate/phosphate ratios added in the A treatment were twice than those added in the SD treatment. Both types of dry aerosols triggered a positive change (25-600% normalized per 1 mg l −1 addition) in most of the rate and state variables that were measured: bacterial abundance (BA), bacterial production (BP), Synechococcus (Syn) abundance, chlorophyll-a (chl-a), primary production (PP), and dinitrogen fixation (N 2 -fix), with relative changes among them following the sequence BP>PP≈N2-fix>chl-a≈BA≈Syn. Our results show that the "polluted" aerosols triggered a relatively larger biological Herut et al.Impact of Aerosols on LNLC Seawater change compared to the SD amendments (per a similar amount of mass addition), especially regarding BP and PP. We speculate that despite the co-limitation of P and N in the EMS, the additional N released by the A treatment may have triggered the relatively larger response in most of the rate and state variables as compared to SD. An implication of our study is that a warmer atmosphere in the future may increase dust emissions and influence the intensity and length of the already well stratified water column in the EMS and hence the impact of the aerosols as a significant external source of new nutrients.

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Aquatic heterotrophic bacteria have highly flexible phosphorus content and biomass stoichiometry

Cited by 83 publications

References 24 publications

Single Cell Analysis Linking Ribosomal (r)DNA and rRNA Copy Numbers to Cell Size and Growth Rate Provides Insights into Molecular Protistan Ecology

Single Cell Analysis Linking Ribosomal (r)DNA and rRNA Copy Numbers to Cell Size and Growth Rate Provides Insights into Molecular Protistan Ecology

Bioavailability of Dissolved Organic Phosphorus in Temperate Lakes

The Potential Impact of Saharan Dust and Polluted Aerosols on Microbial Populations in the East Mediterranean Sea, an Overview of a Mesocosm Experimental Approach

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