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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.


Changes in the average log volume (µm3) of valves of the four dominant Aulacoseira species over the last ∼200 years.Symbols for the four varieties/species of Aulacoseira as in Fig. 1.
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fig-4: Changes in the average log volume (µm3) of valves of the four dominant Aulacoseira species over the last ∼200 years.Symbols for the four varieties/species of Aulacoseira as in Fig. 1.

Mentions: The average area of the small centric diatoms <10 µm in diameter in valve view is 35.5 ± 1.4 (2 SE) µm2, and does not vary significantly with time/depth (Table 1). The average area of Aulacoseira valves range from 96.6 to 109.6 µm2, and in volume from 1,436 to 1,723 µm3, depending on the species and variety. In contrast with the small centric species, the average valve sizes (A, AM, SA, and V) of Aulacoseira lirata var. biseriata, A. lirata var. lirata, A. perglabra var. floriniae but not A. perglabra var. perglabra does change significantly with depth/time (Table 1); increasing in A, SA, and V since ∼1800 AD (Fig. 4). There are small, but significant, changes in the aspect ratio of Aulacoseira with depth (ANOVA, p < 0.05), but no trend towards smaller or larger aspect ratios through time across the species and varieties. The aspect ratio of the Aulacoseira valves (diameter:mantle height) ranges from 1.82 for Aulacoseira lirata var. biseriata and A. florinae var. perglabra to 2.0 and 2.1 for A. lirata var. lirata and A. perglabra var. floriniae, respectively. The average valve size associated with the other species examined (excluding the small centrics <10 µm and Aulacoseira sp.) vary from 92 to 105 µm2 across depth but exhibit no consistent trend over depth/time (Fig. 3).


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)

Changes in the average log volume (µm3) of valves of the four dominant Aulacoseira species over the last ∼200 years.Symbols for the four varieties/species of Aulacoseira as in Fig. 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig-4: Changes in the average log volume (µm3) of valves of the four dominant Aulacoseira species over the last ∼200 years.Symbols for the four varieties/species of Aulacoseira as in Fig. 1.
Mentions: The average area of the small centric diatoms <10 µm in diameter in valve view is 35.5 ± 1.4 (2 SE) µm2, and does not vary significantly with time/depth (Table 1). The average area of Aulacoseira valves range from 96.6 to 109.6 µm2, and in volume from 1,436 to 1,723 µm3, depending on the species and variety. In contrast with the small centric species, the average valve sizes (A, AM, SA, and V) of Aulacoseira lirata var. biseriata, A. lirata var. lirata, A. perglabra var. floriniae but not A. perglabra var. perglabra does change significantly with depth/time (Table 1); increasing in A, SA, and V since ∼1800 AD (Fig. 4). There are small, but significant, changes in the aspect ratio of Aulacoseira with depth (ANOVA, p < 0.05), but no trend towards smaller or larger aspect ratios through time across the species and varieties. The aspect ratio of the Aulacoseira valves (diameter:mantle height) ranges from 1.82 for Aulacoseira lirata var. biseriata and A. florinae var. perglabra to 2.0 and 2.1 for A. lirata var. lirata and A. perglabra var. floriniae, respectively. The average valve size associated with the other species examined (excluding the small centrics <10 µm and Aulacoseira sp.) vary from 92 to 105 µm2 across depth but exhibit no consistent trend over depth/time (Fig. 3).

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.