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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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Ammonium and nitrite gradients in the Eastern English Channel at 3 s intervals.The steepest and largest gradients are at the shortest scales, those most relevant to individual phytoplankton cells.
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pone-0059548-g001: Ammonium and nitrite gradients in the Eastern English Channel at 3 s intervals.The steepest and largest gradients are at the shortest scales, those most relevant to individual phytoplankton cells.

Mentions: To assess the extent of nutrient variation that an individual diatom might experience, we measured inorganic nutrient concentrations in the Eastern English Channel at horizontal intervals ranging from 5 to 45 cm. We found changes over these distances of 2 to 160 times that existed as hotspots on a relatively uniform baseline (Fig. 1). We examined the baseline in two horizontal directions at 5 cm resolution and found centimeter-sized hotspots (Fig. 2) for all nutrients, as well as gradients across the sampling area (Fig. 2c, 2d). These patterns were consistent over the course of the spring bloom, on a seasonal and inter-annual basis. The results show that each nutrient has a distinct and highly variable distribution over distances down to centimeters (Fig. 2).


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)

Ammonium and nitrite gradients in the Eastern English Channel at 3 s intervals.The steepest and largest gradients are at the shortest scales, those most relevant to individual phytoplankton cells.
© Copyright Policy
Related In: Results  -  Collection

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

pone-0059548-g001: Ammonium and nitrite gradients in the Eastern English Channel at 3 s intervals.The steepest and largest gradients are at the shortest scales, those most relevant to individual phytoplankton cells.
Mentions: To assess the extent of nutrient variation that an individual diatom might experience, we measured inorganic nutrient concentrations in the Eastern English Channel at horizontal intervals ranging from 5 to 45 cm. We found changes over these distances of 2 to 160 times that existed as hotspots on a relatively uniform baseline (Fig. 1). We examined the baseline in two horizontal directions at 5 cm resolution and found centimeter-sized hotspots (Fig. 2) for all nutrients, as well as gradients across the sampling area (Fig. 2c, 2d). These patterns were consistent over the course of the spring bloom, on a seasonal and inter-annual basis. The results show that each nutrient has a distinct and highly variable distribution over distances down to centimeters (Fig. 2).

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