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Closely related phytoplankton species produce similar suites of dissolved organic matter.

Becker JW, Berube PM, Follett CL, Waterbury JB, Chisholm SW, Delong EF, Repeta DJ - Front Microbiol (2014)

Bottom Line: Connections between DOMP features and the phylogenetic relatedness of these strains were identified on multiple levels of phylogenetic distance, suggesting that marine phytoplankton produce DOM that in part reflects its phylogenetic origin.Chemical information regarding the size and polarity ranges of features from defined biological sources was also obtained.Our findings reveal DOMP composition to be partially conserved among related phytoplankton species, and implicate marine DOM as a potential factor influencing microbial diversity in the sea by acting as a link between autotrophic and heterotrophic microbial community structures.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Woods Hole Oceanographic Institution Woods Hole, MA, USA ; Department of Civil and Environmental Engineering, Massachusetts Institute of Technology Cambridge, MA, USA.

ABSTRACT
Production of dissolved organic matter (DOM) by marine phytoplankton supplies the majority of organic substrate consumed by heterotrophic bacterioplankton in the sea. This production and subsequent consumption converts a vast quantity of carbon, nitrogen, and phosphorus between organic and inorganic forms, directly impacting global cycles of these biologically important elements. Details regarding the chemical composition of DOM produced by marine phytoplankton are sparse, and while often assumed, it is not currently known if phylogenetically distinct groups of marine phytoplankton release characteristic suites of DOM. To investigate the relationship between specific phytoplankton groups and the DOM they release, hydrophobic phytoplankton-derived dissolved organic matter (DOMP) from eight axenic strains was analyzed using high-performance liquid chromatography coupled to mass spectrometry (HPLC-MS). Identification of DOM features derived from Prochlorococcus, Synechococcus, Thalassiosira, and Phaeodactylum revealed DOMP to be complex and highly strain dependent. Connections between DOMP features and the phylogenetic relatedness of these strains were identified on multiple levels of phylogenetic distance, suggesting that marine phytoplankton produce DOM that in part reflects its phylogenetic origin. Chemical information regarding the size and polarity ranges of features from defined biological sources was also obtained. Our findings reveal DOMP composition to be partially conserved among related phytoplankton species, and implicate marine DOM as a potential factor influencing microbial diversity in the sea by acting as a link between autotrophic and heterotrophic microbial community structures.

No MeSH data available.


Related in: MedlinePlus

Scatter plots illustrating variations in signal intensity among features common to multiple samples. Signal intensity is used as a semi-quantitative proxy for feature abundance. Features are indicated by dots and their location is a function of their signal intensity in the 2 samples labeled on the axes for each plot. Solid lines indicate 1:1 and broken lines indicate 4:1. Variations in common feature intensities are shown for biological replicates (A) indicating some abundance variation among replicate samples. Comparing a culture sample to its respective media control (B) reveals features present in the medium that are produced (above the upper broken line) and consumed (below the lower broken line) by the phytoplankton strain during growth in culture. Variations in common feature intensities can also be compared at multiple levels of phylogenetic variation including at the clade-level (C), genus-level (D), and domain level (E,F), indicating that the quantity of features produced is also related to producer phylogeny.
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Figure 4: Scatter plots illustrating variations in signal intensity among features common to multiple samples. Signal intensity is used as a semi-quantitative proxy for feature abundance. Features are indicated by dots and their location is a function of their signal intensity in the 2 samples labeled on the axes for each plot. Solid lines indicate 1:1 and broken lines indicate 4:1. Variations in common feature intensities are shown for biological replicates (A) indicating some abundance variation among replicate samples. Comparing a culture sample to its respective media control (B) reveals features present in the medium that are produced (above the upper broken line) and consumed (below the lower broken line) by the phytoplankton strain during growth in culture. Variations in common feature intensities can also be compared at multiple levels of phylogenetic variation including at the clade-level (C), genus-level (D), and domain level (E,F), indicating that the quantity of features produced is also related to producer phylogeny.

Mentions: Scatter plots of signal intensity provide a visual representation of semi-quantitative differences among features common to multiple samples (Figure 4). Intensity comparisons above and below a threshold of 4-fold were chosen because the majority of common features (93% on average) among all replicate samples and blanks were within a 4-fold intensity difference (Figure 4A). A representative comparison of common features found in a culture sample (Prochlorococcus str. 9301 replicate C) and its respective media control (Pro99 medium replicate C) demonstrates that while the majority of features (95% on average) are within a 4-fold intensity difference, there was material present in the medium produced (dots above the upper 4:1 line) and consumed (dots below the lower 4:1 line) during phytoplankton growth (Figure 4B). Pairwise comparisons of different strains exhibited greater intensity differences than among replicates, and the degree of intensity differences between strains varied widely. On average, 91% of common features among different Prochlorococcus strains were within a 4-fold intensity difference (Figure 4C). An average of 82% of common features among the different Synechococcus strains were within a 4-fold intensity difference, while 77% of common features were within a 4-fold intensity difference among the different diatom strains. On average, 84% of features common to Prochlorococcus and Synechococcus were within a 4-fold intensity difference, while an average of 75 and 68% of common features were within a 4-fold intensity difference when comparing Prochlorococcus to diatoms and Synechococcus to diatoms, respectively (Figures 4D–F).


Closely related phytoplankton species produce similar suites of dissolved organic matter.

Becker JW, Berube PM, Follett CL, Waterbury JB, Chisholm SW, Delong EF, Repeta DJ - Front Microbiol (2014)

Scatter plots illustrating variations in signal intensity among features common to multiple samples. Signal intensity is used as a semi-quantitative proxy for feature abundance. Features are indicated by dots and their location is a function of their signal intensity in the 2 samples labeled on the axes for each plot. Solid lines indicate 1:1 and broken lines indicate 4:1. Variations in common feature intensities are shown for biological replicates (A) indicating some abundance variation among replicate samples. Comparing a culture sample to its respective media control (B) reveals features present in the medium that are produced (above the upper broken line) and consumed (below the lower broken line) by the phytoplankton strain during growth in culture. Variations in common feature intensities can also be compared at multiple levels of phylogenetic variation including at the clade-level (C), genus-level (D), and domain level (E,F), indicating that the quantity of features produced is also related to producer phylogeny.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3975126&req=5

Figure 4: Scatter plots illustrating variations in signal intensity among features common to multiple samples. Signal intensity is used as a semi-quantitative proxy for feature abundance. Features are indicated by dots and their location is a function of their signal intensity in the 2 samples labeled on the axes for each plot. Solid lines indicate 1:1 and broken lines indicate 4:1. Variations in common feature intensities are shown for biological replicates (A) indicating some abundance variation among replicate samples. Comparing a culture sample to its respective media control (B) reveals features present in the medium that are produced (above the upper broken line) and consumed (below the lower broken line) by the phytoplankton strain during growth in culture. Variations in common feature intensities can also be compared at multiple levels of phylogenetic variation including at the clade-level (C), genus-level (D), and domain level (E,F), indicating that the quantity of features produced is also related to producer phylogeny.
Mentions: Scatter plots of signal intensity provide a visual representation of semi-quantitative differences among features common to multiple samples (Figure 4). Intensity comparisons above and below a threshold of 4-fold were chosen because the majority of common features (93% on average) among all replicate samples and blanks were within a 4-fold intensity difference (Figure 4A). A representative comparison of common features found in a culture sample (Prochlorococcus str. 9301 replicate C) and its respective media control (Pro99 medium replicate C) demonstrates that while the majority of features (95% on average) are within a 4-fold intensity difference, there was material present in the medium produced (dots above the upper 4:1 line) and consumed (dots below the lower 4:1 line) during phytoplankton growth (Figure 4B). Pairwise comparisons of different strains exhibited greater intensity differences than among replicates, and the degree of intensity differences between strains varied widely. On average, 91% of common features among different Prochlorococcus strains were within a 4-fold intensity difference (Figure 4C). An average of 82% of common features among the different Synechococcus strains were within a 4-fold intensity difference, while 77% of common features were within a 4-fold intensity difference among the different diatom strains. On average, 84% of features common to Prochlorococcus and Synechococcus were within a 4-fold intensity difference, while an average of 75 and 68% of common features were within a 4-fold intensity difference when comparing Prochlorococcus to diatoms and Synechococcus to diatoms, respectively (Figures 4D–F).

Bottom Line: Connections between DOMP features and the phylogenetic relatedness of these strains were identified on multiple levels of phylogenetic distance, suggesting that marine phytoplankton produce DOM that in part reflects its phylogenetic origin.Chemical information regarding the size and polarity ranges of features from defined biological sources was also obtained.Our findings reveal DOMP composition to be partially conserved among related phytoplankton species, and implicate marine DOM as a potential factor influencing microbial diversity in the sea by acting as a link between autotrophic and heterotrophic microbial community structures.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Woods Hole Oceanographic Institution Woods Hole, MA, USA ; Department of Civil and Environmental Engineering, Massachusetts Institute of Technology Cambridge, MA, USA.

ABSTRACT
Production of dissolved organic matter (DOM) by marine phytoplankton supplies the majority of organic substrate consumed by heterotrophic bacterioplankton in the sea. This production and subsequent consumption converts a vast quantity of carbon, nitrogen, and phosphorus between organic and inorganic forms, directly impacting global cycles of these biologically important elements. Details regarding the chemical composition of DOM produced by marine phytoplankton are sparse, and while often assumed, it is not currently known if phylogenetically distinct groups of marine phytoplankton release characteristic suites of DOM. To investigate the relationship between specific phytoplankton groups and the DOM they release, hydrophobic phytoplankton-derived dissolved organic matter (DOMP) from eight axenic strains was analyzed using high-performance liquid chromatography coupled to mass spectrometry (HPLC-MS). Identification of DOM features derived from Prochlorococcus, Synechococcus, Thalassiosira, and Phaeodactylum revealed DOMP to be complex and highly strain dependent. Connections between DOMP features and the phylogenetic relatedness of these strains were identified on multiple levels of phylogenetic distance, suggesting that marine phytoplankton produce DOM that in part reflects its phylogenetic origin. Chemical information regarding the size and polarity ranges of features from defined biological sources was also obtained. Our findings reveal DOMP composition to be partially conserved among related phytoplankton species, and implicate marine DOM as a potential factor influencing microbial diversity in the sea by acting as a link between autotrophic and heterotrophic microbial community structures.

No MeSH data available.


Related in: MedlinePlus