TY - JOUR
T1 - The ecology of Pediastrum (Chlorophyceae) in subarctic lakes and their potential as paleobioindicators
AU - Weckström, Kaarina
AU - Weckström, Jan
AU - Yliniemi, Linda-Marie
AU - Korhola, Atte
N1 - Funding Information:
Acknowledgments The Kone Foundation and the Academy of Finland are acknowledged for financial support to J. Weckström andtoK. Weckström. We are grateful to P. Junttila, L. Forsström, M. Rautio and S. Sorvari for sample collection and to L. Forsström for valuable and interesting discussions. S. Juggins is kindly acknowledged for the help with plotting Fig. 4. J. P. Smol and an anonymous reviewer are thanked for constructive comments that helped improving the manuscript.
PY - 2010/1
Y1 - 2010/1
N2 - Subarctic and arctic lakes are the focus of many paleolimnological studies, as they are still among the least impacted lakes by humans. Hence they provide an excellent setting for studies on long-term climatic variability without the overriding effects of direct anthropogenic perturbation. On the other hand, these ecosystems are highly vulnerable to even moderate anthropogenic influence like long-distance airborne transport of nutrients and pollutants. The paleolimnological studies conducted in these areas usually include a multitude of different proxies, but so far only few have used the green algal group of Pediastrum Meyen. These algae, however, preserve well in sediments and can be identified to species level, which lends them potential as a paleo-proxy. In this study we analysed the present Pediastrum assemblages from surface-sediments of 16 subarctic lakes in Finnish Lapland as well as bottom samples from the same sediment cores, which are "spot" samples from the recent past. We found a total of 14 Pediastrum taxa, five of which occurred at moderate to high relative abundances. The majority of the taxa showed distinct relationships to environmental variables measured. Of these, pH and dissolved organic carbon (DOC) explained most of the variance in the distribution of Pediastrum and generally summarised the main environmental gradients in our data set well. Five of the studied lakes lacked Pediastrum taxa altogether, and Pediastrum occurred at low abundances in four additional lakes. All of these nine lakes have extremely low nutrient concentrations and generally lowest pH and DOC in the data set and were defined by barren catchment areas and scarce lake macrophyte growth. According to a top-bottom analysis of sediment cores, the Pediastrum assemblages of the study lakes have changed moderately, suggesting changed environmental conditions in the lakes. Although these changes appear to be climate-related, more studies are needed to confirm this hypothesis.
AB - Subarctic and arctic lakes are the focus of many paleolimnological studies, as they are still among the least impacted lakes by humans. Hence they provide an excellent setting for studies on long-term climatic variability without the overriding effects of direct anthropogenic perturbation. On the other hand, these ecosystems are highly vulnerable to even moderate anthropogenic influence like long-distance airborne transport of nutrients and pollutants. The paleolimnological studies conducted in these areas usually include a multitude of different proxies, but so far only few have used the green algal group of Pediastrum Meyen. These algae, however, preserve well in sediments and can be identified to species level, which lends them potential as a paleo-proxy. In this study we analysed the present Pediastrum assemblages from surface-sediments of 16 subarctic lakes in Finnish Lapland as well as bottom samples from the same sediment cores, which are "spot" samples from the recent past. We found a total of 14 Pediastrum taxa, five of which occurred at moderate to high relative abundances. The majority of the taxa showed distinct relationships to environmental variables measured. Of these, pH and dissolved organic carbon (DOC) explained most of the variance in the distribution of Pediastrum and generally summarised the main environmental gradients in our data set well. Five of the studied lakes lacked Pediastrum taxa altogether, and Pediastrum occurred at low abundances in four additional lakes. All of these nine lakes have extremely low nutrient concentrations and generally lowest pH and DOC in the data set and were defined by barren catchment areas and scarce lake macrophyte growth. According to a top-bottom analysis of sediment cores, the Pediastrum assemblages of the study lakes have changed moderately, suggesting changed environmental conditions in the lakes. Although these changes appear to be climate-related, more studies are needed to confirm this hypothesis.
KW - Multivariate statistics
KW - Paleobioindicators
KW - Pediastrum (Chlorophyceae)
KW - Subarctic lakes
UR - http://www.scopus.com/inward/record.url?scp=77949772076&partnerID=8YFLogxK
U2 - 10.1007/s10933-009-9314-y
DO - 10.1007/s10933-009-9314-y
M3 - Article
SN - 0921-2728
VL - 43
SP - 61
EP - 73
JO - Journal of Paleolimnology
JF - Journal of Paleolimnology
IS - 1
ER -