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Community- and population-level changes in diatom size structure in a subarctic lake over the last two centuries.

Kerrigan EA, Irwin AJ, Finkel ZV - PeerJ (2015)

Bottom Line: Climate change over the last two centuries has been associated with significant shifts in diatom community structure in lakes from the high arctic to temperate latitudes.To test the hypotheses that recent climate warming selects for species of smaller size within communities and a decrease in the average size of species within populations, we quantified the size of individual diatom valves from 10 depths in a sediment core covering the last ∼200 years from a pristine subarctic lake.In the surface sediments that correspond to the recent decades when air temperatures have warmed, the mean size of valves in the diatom community has significantly decreased due to an increase in the proportion of smaller-sized planktonic diatom species.

View Article: PubMed Central - HTML - PubMed

Affiliation: Environmental Science Program, Mount Allison University , Sackville, New Brunswick , Canada.

ABSTRACT
Climate change over the last two centuries has been associated with significant shifts in diatom community structure in lakes from the high arctic to temperate latitudes. To test the hypotheses that recent climate warming selects for species of smaller size within communities and a decrease in the average size of species within populations, we quantified the size of individual diatom valves from 10 depths in a sediment core covering the last ∼200 years from a pristine subarctic lake. Over the last ∼200 years, changes in the relative abundance of species of different average size and changes in the average valve size of populations of species contribute equally to the changes in community size structure, but are often opposite in sign, compensating for one another and moderating temporal changes in community size structure. In the surface sediments that correspond to the recent decades when air temperatures have warmed, the mean size of valves in the diatom community has significantly decreased due to an increase in the proportion of smaller-sized planktonic diatom species.

No MeSH data available.


Change in the size and taxonomic structure of the diatom community and selected sub-populations over the last ∼200 years.From top to bottom: regional spring-summer temperature reconstruction (Szeicz & MacDonald, 1995), the average log10 area (µm2) of valves from the diatom community, the proportion of small centric diatoms with diameters <10 µm in the community; the proportion of Aulacoseira spp. in the community, the proportion of all other species in the community, the average log area (µm2) of the small centric diatoms with diameters <10 µm, the average log area (µm2) of dominant Aulacoseira species, the average log area (µm2) of all the other species in the community. Errors bars represent 95% confidence intervals.
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fig-3: Change in the size and taxonomic structure of the diatom community and selected sub-populations over the last ∼200 years.From top to bottom: regional spring-summer temperature reconstruction (Szeicz & MacDonald, 1995), the average log10 area (µm2) of valves from the diatom community, the proportion of small centric diatoms with diameters <10 µm in the community; the proportion of Aulacoseira spp. in the community, the proportion of all other species in the community, the average log area (µm2) of the small centric diatoms with diameters <10 µm, the average log area (µm2) of dominant Aulacoseira species, the average log area (µm2) of all the other species in the community. Errors bars represent 95% confidence intervals.

Mentions: The 4,899 diatom valves analyzed from Slipper Lake range over ∼2.5 orders of magnitude in area, from a minimum of 7.4 to a maximum of 2169.5 µm2. The smallest valves observed at each depth, 7.4–12 µm2, are unidentified centric diatoms. The largest valves (546.5–2169.5 µm2) are associated with rarely observed Eunotia and unidentified naviculoid species. The distribution of valve areas is right-skewed log-normal. The mean area of the valves (A), including all depths sampled is 81.7 ± 1.95 (2 se) µm2. Over the ten depths sampled the mean area of the valves in the diatom community ranges from 72 to 88 µm2. The mean log10 area of the diatom valves from the community is statistically indistinguishable across most of the depths analyzed with the exception of the surface sediments (∼last 50 years) when the log10 mean area becomes significantly smaller (Table 1 and Fig. 3). There is no significant linear relationship between the mean area of the diatom valves in the community (log A) or proportion of small centrics in the community and local spring-summer temperatures over the last two centuries (linear regression, p > 0.05).


Community- and population-level changes in diatom size structure in a subarctic lake over the last two centuries.

Kerrigan EA, Irwin AJ, Finkel ZV - PeerJ (2015)

Change in the size and taxonomic structure of the diatom community and selected sub-populations over the last ∼200 years.From top to bottom: regional spring-summer temperature reconstruction (Szeicz & MacDonald, 1995), the average log10 area (µm2) of valves from the diatom community, the proportion of small centric diatoms with diameters <10 µm in the community; the proportion of Aulacoseira spp. in the community, the proportion of all other species in the community, the average log area (µm2) of the small centric diatoms with diameters <10 µm, the average log area (µm2) of dominant Aulacoseira species, the average log area (µm2) of all the other species in the community. Errors bars represent 95% confidence intervals.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493642&req=5

fig-3: Change in the size and taxonomic structure of the diatom community and selected sub-populations over the last ∼200 years.From top to bottom: regional spring-summer temperature reconstruction (Szeicz & MacDonald, 1995), the average log10 area (µm2) of valves from the diatom community, the proportion of small centric diatoms with diameters <10 µm in the community; the proportion of Aulacoseira spp. in the community, the proportion of all other species in the community, the average log area (µm2) of the small centric diatoms with diameters <10 µm, the average log area (µm2) of dominant Aulacoseira species, the average log area (µm2) of all the other species in the community. Errors bars represent 95% confidence intervals.
Mentions: The 4,899 diatom valves analyzed from Slipper Lake range over ∼2.5 orders of magnitude in area, from a minimum of 7.4 to a maximum of 2169.5 µm2. The smallest valves observed at each depth, 7.4–12 µm2, are unidentified centric diatoms. The largest valves (546.5–2169.5 µm2) are associated with rarely observed Eunotia and unidentified naviculoid species. The distribution of valve areas is right-skewed log-normal. The mean area of the valves (A), including all depths sampled is 81.7 ± 1.95 (2 se) µm2. Over the ten depths sampled the mean area of the valves in the diatom community ranges from 72 to 88 µm2. The mean log10 area of the diatom valves from the community is statistically indistinguishable across most of the depths analyzed with the exception of the surface sediments (∼last 50 years) when the log10 mean area becomes significantly smaller (Table 1 and Fig. 3). There is no significant linear relationship between the mean area of the diatom valves in the community (log A) or proportion of small centrics in the community and local spring-summer temperatures over the last two centuries (linear regression, p > 0.05).

Bottom Line: Climate change over the last two centuries has been associated with significant shifts in diatom community structure in lakes from the high arctic to temperate latitudes.To test the hypotheses that recent climate warming selects for species of smaller size within communities and a decrease in the average size of species within populations, we quantified the size of individual diatom valves from 10 depths in a sediment core covering the last ∼200 years from a pristine subarctic lake.In the surface sediments that correspond to the recent decades when air temperatures have warmed, the mean size of valves in the diatom community has significantly decreased due to an increase in the proportion of smaller-sized planktonic diatom species.

View Article: PubMed Central - HTML - PubMed

Affiliation: Environmental Science Program, Mount Allison University , Sackville, New Brunswick , Canada.

ABSTRACT
Climate change over the last two centuries has been associated with significant shifts in diatom community structure in lakes from the high arctic to temperate latitudes. To test the hypotheses that recent climate warming selects for species of smaller size within communities and a decrease in the average size of species within populations, we quantified the size of individual diatom valves from 10 depths in a sediment core covering the last ∼200 years from a pristine subarctic lake. Over the last ∼200 years, changes in the relative abundance of species of different average size and changes in the average valve size of populations of species contribute equally to the changes in community size structure, but are often opposite in sign, compensating for one another and moderating temporal changes in community size structure. In the surface sediments that correspond to the recent decades when air temperatures have warmed, the mean size of valves in the diatom community has significantly decreased due to an increase in the proportion of smaller-sized planktonic diatom species.

No MeSH data available.