Jacob Champeau and David Strong, Faculty Advisor: Dr ...
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ACKNOWLEDGEMENTS Quantifying ecological change in diatom diversity in paleolimnological records from lakes in Sweden. FUTURE WORK . . CONCLUSIONS RESULTS INTRODUCTION METHODS LITERATURE CITED Funding provided by University Personnel Development Committee New faculty Grant, Undergraduate Education Initiative Grant. Special thanks to: Caleb Slemmons for field work, Dr. CT Hess and John Cummings for 210 Pb dating analysis, Dr. Kristin Engstrom and Dr Jannie Linneberg for Sweden logistics, and Dr. Chris Hartleb, Dr. Pete Zani and Dr. Samantha Kaplan for lab space and equipment. How does species richness vary spatially among regions with different atmospheric deposition? How has species richness changed over time and between regions in Swedish lakes? RESULTS QUESTIONS Jacob Champeau and David Strong, Faculty Advisor: Dr. Krista Slemmons Department of Biology, University of Wisconsin-Stevens Point Fig 2. Extruded lake sediment core from Lake Barsjön, Southwest Sweden. Fig 5. Lake Lilla Ulvattnet, Southwest Sweden, coring site. Figure 1. Location of study site situated in southern Sweden. Region 1 represents high nitrogen deposition areas and is the location of Lake Bärsjön. Region 2 represents relatively lower nitrogen deposition and the location of Lake Furbosjön. Regions were designated and map was adapted from Bergström et al. 2008 2 . Table 1. Select characteristics of study lakes. DIN = dissolved organic nitrate 2 . Region Lake Name Lake area (km 2 ) DIN Ave for region (kg N km-2 yr- 1) 1 Lilla Ulvattnet 0.1913 800 Bärsjön 0.5689 2 Furbosjön 0.5894 434 Ysjön 0.2864 1. Analysis of top/bottom sections in two more Swedish lakes: Lilla Ulvattnet and Ysjon. 2. Detailed diatom counts for all depths in the four study lakes. 3. Comparisons of similar time periods between lakes once cores are dated. 4. Conduct Loss-on-ignition data analysis and compare between lakes. 5. Conduct beta-diversity and community turnover analyses The future analysis of a larger data set will allow for a more thorough look at environmental change from both a wider geographic region and a more comprehensive time span. 1 Elser, J., Anderson, T., Baron, S., Bergstrom, A., Jansson, M., Kyle, M., Koren, R., Steger, L., Hessen, Dag. Shifts in Lake N:P Stoichiometry and Nutrient Limitation Driven by Atmospheric Nitrogen Deposition. 2009. Science 326: 835-837. 2 Bergstrom, A.L., Jonsson, A., Jansson, M. Phytoplankton responses to nitrogen and phosphorus enrichment in unproductive Swedish lakes along a gradient of atmospheric nitrogen deposition. 2008. Aquatic Biology 4: 55-64. 3 Saros, J., Stone, J., Pederson, G., Slemmons, K., Spanbauer, T., Schliep, A., Cah D., Williamson, C., Engstrom, D. Climate-induced changes in lake ecosystem structure inferred from coupled neo- and paleoecological approaches. 2012 Ecology 93: 2155-2164. •Cores collected the deepest part from four Swedish lakes via HTH gravity corer in Summer 2014. •Extruded 0.5 cm segments and processed for diatoms (Fig 2). Enumerated and identified diatoms via microscopy in top (modern) and bottom (past) core segments. Dated each core using 210 Pb dating techniques. Calculated and compared the species relative abundance and richness using Rarefaction to standardize to 300 valves per sample. Calculated species evenness and compared between times and among lakes. Compared species composition across lakes. ●Paleolimnology is the study of the sedimentary record of lakes and can be used to reconstruct environmental history of a region beyond recorded history. ● Diatoms preserve in lake sediment and are sensitive to changes in lake chemistry, serving as indicators for environmental change. ● The effects on atmospheric nitrogen on lake biota is not as well-understood as the effects of other elements such as phosphorous but changes in limiting nutrients in Scandinavian countries and the U.S Rocky Mountains have been attributed to increased atmospheric nitrogen deposition 1,2 . ● Changes in diatom community structure over time can indicate changes in atmospheric nitrogen deposition over time. ● This study focuses on determining if diatom species richness varies regional in Swedish lakes with degree of atmospheric nitrogen deposition (Table 1, Fig 1). ● Knowledge of the effect of nitrogen on species richness and diversity can allow for predictions of nitrogen thresholds required to elicit ecological change and can inform policy making decisions in setting allows for predictions environmental conditions to be estimated for the time period lining up with that segment depth. Fig 4. A) Diatom stratigraphy of key diatom species linked to differences in mixing depth 3 : D. stelligera relatively shallow mixing and C. bodanica relatively deeper mixing. Both lakes indicate change over time in regard to mixing depths. B) Sample diatom specimens taken from Lake Barsjön. Cyclotella bodanica (left), B) Discostella stelligera (right). Figure 3. Comparison of species evenness in the A) Past to B) Modern samples. No difference in evenness between Barsjön and Furbosjön in the past (t-test, p=0.93) or in the modern samples (t-test, p=0.75). 13.5 14 14.5 15 15.5 16 16.5 17 17.5 Furbosjon Barsjon Furbosjon Barsjon Average Species Richness (E S300 ) Modern Past Figure 4. Comparison of species richness in Past and Modern samples based Analytic Rarefaction 1.3 (n=300 [E S300 ] for every sample, S. Holland). No difference in evenness between Barsjön and Furbosjön in the past. -10 -5 0 5 10 15 20 25 30 35 40 Depth (cm) 0 20 Furbosjon 0 20 40 60 Relative percent abundance Barsjon 0 20 40 Furbosjon 0 Barsjon Discostella stelligera Cyclotella bodanica A B ●Based on limited sample size, no difference In species evenness spatially, however there is an indication of difference temporally. ● Apparent differences in species Composition of two key species over time. ● No apparent difference in species richness.
Transcript of Jacob Champeau and David Strong, Faculty Advisor: Dr ...
ACKNOWLEDGEMENTS
Quantifying ecological change in diatom diversity in paleolimnological records from lakes in Sweden.
FUTURE WORK
.
.
CONCLUSIONS
RESULTS
INTRODUCTION
METHODS
LITERATURE CITED
Funding provided by University Personnel Development Committee New faculty Grant, Undergraduate Education Initiative Grant. Special thanks to: Caleb Slemmons for field work, Dr. CT Hess and John Cummings for 210Pb dating analysis, Dr. Kristin Engstrom and Dr Jannie Linneberg for Sweden logistics, and Dr. Chris Hartleb, Dr. Pete Zani and Dr. Samantha Kaplan for lab space and equipment.
How does species richness vary spatially among regions with different atmospheric deposition?
How has species richness changed over time and between regions in Swedish lakes?
RESULTS
QUESTIONS
Jacob Champeau and David Strong, Faculty Advisor: Dr. Krista Slemmons Department of Biology, University of Wisconsin-Stevens Point
Fig 2. Extruded lake sediment core from Lake Barsjön, Southwest Sweden.
Fig 5. Lake Lilla Ulvattnet, Southwest Sweden, coring site.
Figure 1. Location of study site situated in southern Sweden. Region 1 represents high nitrogen deposition areas and is the location of Lake Bärsjön. Region 2 represents relatively lower nitrogen deposition and the location of Lake Furbosjön. Regions were designated and map was adapted from Bergström et al. 20082.
Table 1. Select characteristics of study lakes. DIN = dissolved organic nitrate2.
Region Lake Name Lake area (km2)
DIN Ave for region
(kg N km-2 yr-1)
1
Lilla Ulvattnet
0.1913 800
Bärsjön 0.5689
2 Furbosjön 0.5894 434
Ysjön 0.2864
1. Analysis of top/bottom sections in two more Swedish lakes: Lilla Ulvattnet and Ysjon. 2. Detailed diatom counts for all depths in the four study lakes. 3. Comparisons of similar time periods between lakes once cores are dated. 4. Conduct Loss-on-ignition data analysis and compare between lakes. 5. Conduct beta-diversity and community turnover analyses The future analysis of a larger data set will allow for a more thorough look at environmental change from both a wider geographic region and a more comprehensive time span.
1Elser, J., Anderson, T., Baron, S., Bergstrom, A., Jansson, M., Kyle, M., Koren, R., Steger, L., Hessen, Dag. Shifts in Lake N:P Stoichiometry and Nutrient Limitation Driven by Atmospheric Nitrogen Deposition. 2009. Science 326: 835-837. 2Bergstrom, A.L., Jonsson, A., Jansson, M. Phytoplankton responses to nitrogen and phosphorus enrichment in unproductive Swedish lakes along a gradient of atmospheric nitrogen deposition. 2008. Aquatic Biology 4: 55-64. 3Saros, J., Stone, J., Pederson, G., Slemmons, K., Spanbauer, T., Schliep, A., Cah D., Williamson, C., Engstrom, D. Climate-induced changes in lake ecosystem structure inferred from coupled neo- and paleoecological approaches. 2012 Ecology 93: 2155-2164.
•Cores collected the deepest part from four
Swedish lakes via HTH gravity corer in Summer 2014. •Extruded 0.5 cm segments and processed for diatoms (Fig 2). Enumerated and identified diatoms via microscopy in top (modern) and bottom (past) core segments.
Dated each core using 210Pb dating techniques.
Calculated and compared the species relative
abundance and richness using Rarefaction to standardize to 300 valves per sample.
Calculated species evenness and compared between times and among lakes.
Compared species composition across lakes.
●Paleolimnology is the study of the sedimentary record of lakes and can be used to reconstruct environmental history of a region beyond recorded history.
● Diatoms preserve in lake sediment and are sensitive to changes in lake chemistry, serving as indicators for environmental change. ● The effects on atmospheric nitrogen on lake biota is not as well-understood as the effects of other elements such as phosphorous but changes in limiting nutrients in Scandinavian countries and the U.S Rocky Mountains have been attributed to increased atmospheric nitrogen deposition1,2. ● Changes in diatom community structure over time can indicate changes in atmospheric nitrogen deposition over time. ● This study focuses on determining if diatom species richness varies regional in Swedish lakes with degree of atmospheric nitrogen deposition (Table 1, Fig 1). ● Knowledge of the effect of nitrogen on species richness and diversity can allow for predictions of nitrogen thresholds required to elicit ecological change and can inform policy making decisions in setting allows for predictions environmental conditions to be estimated for the time period lining up with that segment depth.
Fig 4. A) Diatom stratigraphy of key diatom species linked to differences in mixing depth3: D. stelligera relatively shallow mixing and C. bodanica relatively deeper mixing. Both lakes indicate change over time in regard to mixing depths. B) Sample diatom specimens taken from Lake Barsjön. Cyclotella bodanica (left), B) Discostella stelligera (right).
Figure 3. Comparison of species evenness in the A) Past to B) Modern samples. No difference in evenness between Barsjön and Furbosjön in the past (t-test, p=0.93) or in the modern samples (t-test, p=0.75).
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Furbosjon Barsjon Furbosjon BarsjonAve
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Figure 4. Comparison of species richness in Past and Modern samples based Analytic Rarefaction 1.3 (n=300 [ES300] for every sample, S. Holland). No difference in evenness between Barsjön and Furbosjön in the past.
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Discostella stelligera Cyclotella bodanica A B
●Based on limited sample size, no difference In species evenness spatially, however there is an indication of difference temporally. ● Apparent differences in species Composition of two key species over time. ● No apparent difference in species richness.
