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The role of diatom nanostructures in biasing diffusion to improve uptake in a patchy nutrient environment.

Mitchell JG, Seuront L, Doubell MJ, Losic D, Voelcker NH, Seymour J, Lal R - PLoS ONE (2013)

Bottom Line: Diffusion constraint explains the success of particular diatom species at given times and the overall success of diatoms.The results help answer the unresolved question of how adjacent microplankton compete.Furthermore, diffusion constraint by supramembrane nanostructures to alter molecular diffusion suggests that microbes compete via supramembrane topology, a competitive mechanism not considered by the standard smooth-surface equations used for nutrient uptake nor in microbial ecology and cell physiology.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, Flinders University, Adelaide, South Australia, Australia. jim.mitchell@flinders.edu.au

ABSTRACT

Background: Diatoms are important single-celled autotrophs that dominate most lit aquatic environments and are distinguished by surficial frustules with intricate designs of unknown function.

Principal findings: We show that some frustule designs constrain diffusion to positively alter nutrient uptake. In nutrient gradients of 4 to 160 times over <5 cm, the screened-chambered morphology of Coscincodiscus sp. biases the nutrient diffusion towards the cell by at least 3.8 times the diffusion to the seawater. In contrast, the open-chambers of Thalassiosira eccentrica produce at least a 1.3 times diffusion advantage to the membrane over Coscincodiscus sp. when nutrients are homogeneous.

Significance: Diffusion constraint explains the success of particular diatom species at given times and the overall success of diatoms. The results help answer the unresolved question of how adjacent microplankton compete. Furthermore, diffusion constraint by supramembrane nanostructures to alter molecular diffusion suggests that microbes compete via supramembrane topology, a competitive mechanism not considered by the standard smooth-surface equations used for nutrient uptake nor in microbial ecology and cell physiology.

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Three representative examples of 90 profiles of chlorophyll fluorescence taken over 3 months in the eastern English Channel.They are from 23/3/04 (a), 26/5/04 (b) and 20/6/04 (c). Fluorescence measurements are in relative arbitrary units (a.u.). Expanded sections of b, showing the regularity of peak spacing (d) and the variety of peak width and height (e). The baseline is 25 times below the highest peak. Noise levels were under 200 a.u.
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pone-0059548-g003: Three representative examples of 90 profiles of chlorophyll fluorescence taken over 3 months in the eastern English Channel.They are from 23/3/04 (a), 26/5/04 (b) and 20/6/04 (c). Fluorescence measurements are in relative arbitrary units (a.u.). Expanded sections of b, showing the regularity of peak spacing (d) and the variety of peak width and height (e). The baseline is 25 times below the highest peak. Noise levels were under 200 a.u.

Mentions: To further increase resolution and obtain continuous vertical profiles, phytoplankton distributions, as indicated by fluorescence, were used as a proxy for nutrient distributions, based on the reasoning that phytoplankton biomass and nutrient concentration would be inversely related. Fluorescence varied by up to 35 times over 5 cm of depth, and at less than 5 cm, fluorescence variations of 5 to 25 times were common (Fig. 3). More specifically, ninety vertical profiles over 3 months during the spring bloom in the Eastern English Channel showed that the bloom occurred by the proliferation of ubiquitous millimeter to centimeter-scale micropatches of fluorescence, indicating that centimeter scale patches and millimeter scale gradients are common in time as well as space (Fig. 3).


The role of diatom nanostructures in biasing diffusion to improve uptake in a patchy nutrient environment.

Mitchell JG, Seuront L, Doubell MJ, Losic D, Voelcker NH, Seymour J, Lal R - PLoS ONE (2013)

Three representative examples of 90 profiles of chlorophyll fluorescence taken over 3 months in the eastern English Channel.They are from 23/3/04 (a), 26/5/04 (b) and 20/6/04 (c). Fluorescence measurements are in relative arbitrary units (a.u.). Expanded sections of b, showing the regularity of peak spacing (d) and the variety of peak width and height (e). The baseline is 25 times below the highest peak. Noise levels were under 200 a.u.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3646848&req=5

pone-0059548-g003: Three representative examples of 90 profiles of chlorophyll fluorescence taken over 3 months in the eastern English Channel.They are from 23/3/04 (a), 26/5/04 (b) and 20/6/04 (c). Fluorescence measurements are in relative arbitrary units (a.u.). Expanded sections of b, showing the regularity of peak spacing (d) and the variety of peak width and height (e). The baseline is 25 times below the highest peak. Noise levels were under 200 a.u.
Mentions: To further increase resolution and obtain continuous vertical profiles, phytoplankton distributions, as indicated by fluorescence, were used as a proxy for nutrient distributions, based on the reasoning that phytoplankton biomass and nutrient concentration would be inversely related. Fluorescence varied by up to 35 times over 5 cm of depth, and at less than 5 cm, fluorescence variations of 5 to 25 times were common (Fig. 3). More specifically, ninety vertical profiles over 3 months during the spring bloom in the Eastern English Channel showed that the bloom occurred by the proliferation of ubiquitous millimeter to centimeter-scale micropatches of fluorescence, indicating that centimeter scale patches and millimeter scale gradients are common in time as well as space (Fig. 3).

Bottom Line: Diffusion constraint explains the success of particular diatom species at given times and the overall success of diatoms.The results help answer the unresolved question of how adjacent microplankton compete.Furthermore, diffusion constraint by supramembrane nanostructures to alter molecular diffusion suggests that microbes compete via supramembrane topology, a competitive mechanism not considered by the standard smooth-surface equations used for nutrient uptake nor in microbial ecology and cell physiology.

View Article: PubMed Central - PubMed

Affiliation: School of Biological Sciences, Flinders University, Adelaide, South Australia, Australia. jim.mitchell@flinders.edu.au

ABSTRACT

Background: Diatoms are important single-celled autotrophs that dominate most lit aquatic environments and are distinguished by surficial frustules with intricate designs of unknown function.

Principal findings: We show that some frustule designs constrain diffusion to positively alter nutrient uptake. In nutrient gradients of 4 to 160 times over <5 cm, the screened-chambered morphology of Coscincodiscus sp. biases the nutrient diffusion towards the cell by at least 3.8 times the diffusion to the seawater. In contrast, the open-chambers of Thalassiosira eccentrica produce at least a 1.3 times diffusion advantage to the membrane over Coscincodiscus sp. when nutrients are homogeneous.

Significance: Diffusion constraint explains the success of particular diatom species at given times and the overall success of diatoms. The results help answer the unresolved question of how adjacent microplankton compete. Furthermore, diffusion constraint by supramembrane nanostructures to alter molecular diffusion suggests that microbes compete via supramembrane topology, a competitive mechanism not considered by the standard smooth-surface equations used for nutrient uptake nor in microbial ecology and cell physiology.

Show MeSH