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Size of Dominant Diatom Species Can Alter Their Evenness.

Sugie K, Suzuki K - PLoS ONE (2015)

Bottom Line: We found that the two most useful evenness indices increased in most cases where small species were numerically dominant when calculations were based on biomass compared with those on abundance.The results suggest that the size of the dominant species is a crucial factor in determining the role of diatoms in the ecosystem functioning.Because such size variability can also be observed in other organisms, we need to pay attention to the effect of size structures on biodiversity.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Hokkaido, Japan; CREST, Japan Science and Technology Agency, Sapporo, Hokkaido, Japan.

ABSTRACT
Traditionally, biodiversity has often been estimated on the basis of abundance partly due to the need for complicated measurements of biomass. Here, we conducted robust measurements of the community composition and of the size structure of diatoms in the North Pacific to evaluate the importance of biomass on the biodiversity. We found that the two most useful evenness indices increased in most cases where small species were numerically dominant when calculations were based on biomass compared with those on abundance. Size-abundance spectra of diatoms revealed that numerically dominant small species rarely dominated in terms of biomass. On the other hand, intermediate to large diatom species generally played a dominant role in terms of biomass in diatom community. The results suggest that the size of the dominant species is a crucial factor in determining the role of diatoms in the ecosystem functioning. Because such size variability can also be observed in other organisms, we need to pay attention to the effect of size structures on biodiversity.

No MeSH data available.


(a) Biomass-ESD and (b) abundance-ESD spectra of diatoms in the North Pacific.Scattered diagrams (gray dots) represent the relationships between relative (a) biomass or (b) abundance and ESD of pooled samples. Boxplot represents the (a) biomass and (b) abundance of the each size class, established in an octave (log2) scale. Black circle, box, bars, and crosses represent the mean values of each group, ranges for 25–75% of data, ranges for 1–99% of data, and outliers, respectively.
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pone.0131454.g004: (a) Biomass-ESD and (b) abundance-ESD spectra of diatoms in the North Pacific.Scattered diagrams (gray dots) represent the relationships between relative (a) biomass or (b) abundance and ESD of pooled samples. Boxplot represents the (a) biomass and (b) abundance of the each size class, established in an octave (log2) scale. Black circle, box, bars, and crosses represent the mean values of each group, ranges for 25–75% of data, ranges for 1–99% of data, and outliers, respectively.

Mentions: We found that the relative biomass increased rapidly with increasing cell size from ~1 to ~5 μm in ESD and steadily increased with increasing cell size > 5 μm in ESD (Fig 4A). The relative biomass of extremely large cells (ESD: > 100 μm) tended to dominate in a diatom community once they occurred even with low abundance (< ~50 cells L−1). However, note that the frequency of occurrence of such large species was relatively low and the data error could potentially be large. When extremely large cells were absent in a sample, intermediate-sized species tended to dominate in a diatom community in terms of biomass (Fig 4A). In contrast to the relative biomass-cell volume spectrum, relative abundance-ESD spectrum showed a unimodal distribution, with a peak around 3–5 μm in ESD (Fig 4B). The relative abundance monotonously decreased with increasing cell size > 5 μm in ESD.


Size of Dominant Diatom Species Can Alter Their Evenness.

Sugie K, Suzuki K - PLoS ONE (2015)

(a) Biomass-ESD and (b) abundance-ESD spectra of diatoms in the North Pacific.Scattered diagrams (gray dots) represent the relationships between relative (a) biomass or (b) abundance and ESD of pooled samples. Boxplot represents the (a) biomass and (b) abundance of the each size class, established in an octave (log2) scale. Black circle, box, bars, and crosses represent the mean values of each group, ranges for 25–75% of data, ranges for 1–99% of data, and outliers, respectively.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4476557&req=5

pone.0131454.g004: (a) Biomass-ESD and (b) abundance-ESD spectra of diatoms in the North Pacific.Scattered diagrams (gray dots) represent the relationships between relative (a) biomass or (b) abundance and ESD of pooled samples. Boxplot represents the (a) biomass and (b) abundance of the each size class, established in an octave (log2) scale. Black circle, box, bars, and crosses represent the mean values of each group, ranges for 25–75% of data, ranges for 1–99% of data, and outliers, respectively.
Mentions: We found that the relative biomass increased rapidly with increasing cell size from ~1 to ~5 μm in ESD and steadily increased with increasing cell size > 5 μm in ESD (Fig 4A). The relative biomass of extremely large cells (ESD: > 100 μm) tended to dominate in a diatom community once they occurred even with low abundance (< ~50 cells L−1). However, note that the frequency of occurrence of such large species was relatively low and the data error could potentially be large. When extremely large cells were absent in a sample, intermediate-sized species tended to dominate in a diatom community in terms of biomass (Fig 4A). In contrast to the relative biomass-cell volume spectrum, relative abundance-ESD spectrum showed a unimodal distribution, with a peak around 3–5 μm in ESD (Fig 4B). The relative abundance monotonously decreased with increasing cell size > 5 μm in ESD.

Bottom Line: We found that the two most useful evenness indices increased in most cases where small species were numerically dominant when calculations were based on biomass compared with those on abundance.The results suggest that the size of the dominant species is a crucial factor in determining the role of diatoms in the ecosystem functioning.Because such size variability can also be observed in other organisms, we need to pay attention to the effect of size structures on biodiversity.

View Article: PubMed Central - PubMed

Affiliation: Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Hokkaido, Japan; CREST, Japan Science and Technology Agency, Sapporo, Hokkaido, Japan.

ABSTRACT
Traditionally, biodiversity has often been estimated on the basis of abundance partly due to the need for complicated measurements of biomass. Here, we conducted robust measurements of the community composition and of the size structure of diatoms in the North Pacific to evaluate the importance of biomass on the biodiversity. We found that the two most useful evenness indices increased in most cases where small species were numerically dominant when calculations were based on biomass compared with those on abundance. Size-abundance spectra of diatoms revealed that numerically dominant small species rarely dominated in terms of biomass. On the other hand, intermediate to large diatom species generally played a dominant role in terms of biomass in diatom community. The results suggest that the size of the dominant species is a crucial factor in determining the role of diatoms in the ecosystem functioning. Because such size variability can also be observed in other organisms, we need to pay attention to the effect of size structures on biodiversity.

No MeSH data available.