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Nutrient contributions from Dreissena spp. to Lyngbya wollei and Cladophora glomerata

Nutrient contributions from Dreissena spp. to Lyngbya wollei and Cladophora glomerata. Patricia Armenio Department of Environmental Sciences and the Lake Erie Center University of Toledo. What are local-scale interactions between Dreissena and benthic algae?. System level.

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Nutrient contributions from Dreissena spp. to Lyngbya wollei and Cladophora glomerata

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  1. Nutrient contributions from Dreissena spp. to Lyngbya wollei and Cladophora glomerata Patricia Armenio Department of Environmental Sciences and the Lake Erie Center University of Toledo

  2. What are local-scale interactions between Dreissena and benthic algae? System level Increased light penetration Local level Resource importation Structural complexity Benthic Primary Production

  3. Contribution to algae N & P Ammonium and phosphate CO2 Respiration Decomposition Feces and pseudofeces Organic matter Other nutrients? Structure Hard shells increase surface area P. Bichier

  4. Do Dreissena contribute to benthic algal blooms? Not new to Lake Erie Have increased Decrease aesthetic value Health risks Food web structure What mechanisms from Dreissena facilitate these blooms?

  5. Lyngbya wollei Cyanobacterium Common in southeastern US Recently washed up on shores of Lake Erie Requires relatively low light Does not attach to hard surfaces Toxic? P. Bichier J. Joyner

  6. Cladophora glomerata • Green alga • Requires relatively high light and hard substrate • Blooms common from 1950s through early 1980s • Return of blooms since mid- 1990s not associated with P loading • Dreissena Higgins et al. 2008

  7. 2009 Lyngbya survey • 140 sites total • 113 sites had dreissenid substrate • 77 sites had Lyngbya • 72 sites had both • Only 5 sites that had Lyngbya did not have dreissenid substrate Panek et al.

  8. Manipulative Experiments • Objective: test possible reasons why Dreissena may promote the growth of benthic algae and encourage blooms • N, P • C • Other nutrients • 10 others quantified • Structure

  9. Experimental set-up

  10. 4 treatments 3400 Dreissena/m2 230 g/m2Lyngbya Low-P lake water 12 hour photoperiod One week N=40 Lyngbya Experiment Live Dreissena (N=10) Pottery shards (N=10) Empty Dreissena (N=10) Sand (N=10)

  11. Fed Dreissena throughout experiment • Chlamydomonas reinhardtii • Phytoplankton • Labeled with stable isotope • 13C • 15N • Given to all tanks

  12. Laboratory Analyses • C and N • CHN analyzer • P and other nutrients • ICP-OES • Chlorophyll a • UV-visible spectrophotometer • Phycocyanin • 10-AU fluorometer • Photosynthetic efficiency • DIVING-PAM fluorometer • 13C and 15N • Samples sent to UC Davis, CA

  13. 3 2.5 2 y = 0.1538x + 0.1367 1.5 dry weight (g) 2 R = 0.798 p<0.0001 1 0.5 0 0 5 10 15 20 wet weight (g) Lyngbya Positive correlation between wet weight and dry weight

  14. 70 60 50 40 % increase in wet weight 30 20 10 0 2.5 2 1.5 Dry weight (g) 1 0.5 0 live Dreissena empty Dreissena pottery shards sand substrate type Lyngbya All tanks increase in weight, but no difference among treatments Error bars = SE

  15. 0.5 0.45 0.4 0.35 0.3 Photosynthetic efficiency 0.25 0.2 0.15 0.1 0.05 0 live Dreissena empty Dreissena pottery shards sand substrate type 3 2.5 2 dry weight (g) 1.5 y = -2.8267x + 2.9382 1 R2 = 0.3987 p<0.0001 0.5 0 0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 photosynthetic efficiency Lyngbya No difference in photosynthetic efficiency, but decreases with more dry weight

  16. 500 450 400 350 Chlorophyll a (µg/g) 300 250 200 150 100 50 0 6000 5000 4000 Phycocyanin (µg/g) 3000 2000 1000 0 live Dreissena empty Dreissena pottery shards sand substrate type Lyngbya No difference in chlorophyll a, but higher phycocyanin in live Dreissena treatment A AB BC C

  17. 400 A 350 B B B 300 250 200 Carbon (mg/g) 150 100 50 0 live Dreissena empty Dreissena pottery shards sand substrate type Lyngbya Dreissena increased carbon content in tissue

  18. 6 5 4 Phosphorus (mg/g) 3 2 1 0 45 40 35 30 Nitrogen (mg/g) 25 20 15 10 5 0 live Dreissena empty Dreissena pottery shards sand substrate type Lyngbya Dreissena helped retain macronutrient content in tissue A B B B A B B B

  19. 120 100 80 C:P ratio 60 40 20 0 12 10 8 C:N ratio 6 4 2 0 live Dreissena empty Dreissena pottery shards sand substrate type Lyngbya No P deficiency, but N deficiency in all treatments except live Dreissena B B B • <143 is no Pdeficiency • >9.4 C:N is a N deficiency • No deficiency in live Dreissena treatment A B B B A Kahlert 1998

  20. 4 3.5 3 2.5 Potassium (mg/g) 2 1.5 1 0.5 0 4 3.5 3 2.5 Sulfur (mg/g) 2 1.5 1 0.5 0 live Dreissena empty Dreissena pottery shards sand substrate type Lyngbya Dreissena helped retain nutrient content in tissue A B B B A B B B

  21. 160 B B B 140 A 120 100 Calcium (mg/g) 80 60 40 20 0 live Dreissena empty Dreissena pottery shards sand substrate type Lyngbya However…

  22. -25 A -20 B B B -15 δ13C (‰) -10 -5 0 live Dreissena empty Dreissena pottery shards sand substrate type Lyngbya Stable isotope: less 13C in live Dreissena treatment, no significant difference in 15N

  23. 3 B B B 2.5 A 2 δ 15N (‰) 1.5 1 0.5 0 live Dreissena empty Dreissena pottery shards sand substrate type Two week preliminary experiment with Cladophora: the 13C difference goes away and there becomes a significant difference in 15N

  24. Summary for Lyngbya • Dreissena did not increase the biomass of Lyngbya • Increased phycocyanin • Supplied several nutrients, prevented a decrease in others • Decreased Ca • Decreased 13C • Did not respond to substrates

  25. 4 treatments 3400 Dreissena/m2 160 g/m2 algae Low-P lake water One week 12 hour photoperiod N=40 Fed Chlamydomonas Cladophora Experiment Live Dreissena (N=10) Pottery shards (N=10) Empty Dreissena (N=10) Sand (N=10)

  26. Extra data for Cladophora • Took algal samples after 24 hours and 48 hours • Tissue nutrient content • Stable isotope • Water samples from each tank at end of experiment compared to initial water • Nutrient

  27. 3 2.5 2 dry weight (g) 1.5 y = 0.1387x + 0.4254 R2 = 0.6933 1 p<0.0001 0.5 0 0 2 4 6 8 10 12 14 16 18 wet weight (g) Cladophora Positive correlation between wet weight and dry weight

  28. 80 70 60 50 % increase in wet weight 40 30 20 10 0 12 A B 10 bottom biomass 8 wet weight (g) 6 4 2 0 live Dreissena pottery shards sand empty Dreissena substrate type Cladophora All tanks increase in weight, significant difference when other treatments are grouped

  29. 2 1.8 1.6 1.4 bottom biomass 1.2 dry weight (g) 1 0.8 0.6 0.4 0.2 0 empty Dreissena pottery shards sand live Dreissena substrate type Cladophora Separation in biomass, more with live Dreissena

  30. Cladophora Results • More variability than Lyngbya • No difference in pigments among treatments • Chl a or b • No difference in photosynthetic efficiency among treatments

  31. 0.8 0.7 0.6 0.5 Photosynthetic efficiency 0.4 0.3 0.2 0.1 0 first last day Cladophora Photosynthetic efficiency significantly decreased at end

  32. 340 320 300 Carbon (mg/g) 280 live Dreissena empty Dreissena 260 pottery shards sand 240 220 200 day 1 day 2 day 7 Cladophora Nutrient tissue was significantly different between days, but not treatments

  33. 4.5 4 3.5 3 2.5 Phosphorus (mg/g) 2 1.5 40 1 live Dreissena 35 empty Dreissena 0.5 30 pottery shards sand 0 25 20 Nitrogen (mg/g) 15 10 5 0 day 1 day 2 day 7 Cladophora Trend of higher nutrient concentration with live Dreissena

  34. 180 160 140 120 100 C:P ratio 80 60 40 20 0 live Dreissena empty Dreissena 16 pottery shards sand 14 12 10 8 6 C:N ratio 4 2 0 day 1 day 2 day 7 Cladophora No P deficiency, but N deficiency in all treatments • <143 is no P deficiency • >9.4 C:N is a N deficiency Kahlert 1998

  35. 30 25 20 15 Potassium (mg/g) 10 5 live Dreissena 0 empty Dreissena pottery shards sand 25 20 15 Sulfur (mg/g) 10 5 0 Cladophora K showed more distinct pattern at end, but was not significantly different day 1 day 2 day 7

  36. 45 40 35 30 200 Calcium (mg/l) 25 20 150 15 Calcium (mg/g) 10 100 5 0 50 0 day 7 day 1 day 2 Cladophora Marginally significantly difference in tissue calcium, significant decrease in water initial end

  37. Summary for Cladophora • Showed a biomass increase in the live Dreissena treatment • No significant difference among pigments • Showed trends of higher nutrient concentrations in live Dreissena treatment • C, N, P, K, S • Dreissena decreased Ca concentration • **Not yet received results for 13C and 15N • Did not respond to structure

  38. Overall Conclusions: growth • Dreissena increased growth in Cladophora, but not Lyngbya • Cladophora responded to increased nutrients • Dilution • Attachment

  39. Overall Conclusions: growth • Dreissena increased growth in Cladophora, but not Lyngbya • Cladophora responded to increased nutrients • Dilution • Attachment • Not enough time for Lyngbya • Lyngbya growth does not always positively respond to N and P • Increased PC and nutrients indicate that Lyngbya was photosynthetically healthier with Dreissena

  40. Overall Conclusions: nutrients • Dreissena can retain nutrient concentrations in benthic algae • Can translate to increase biomass over time • More than just C, N, P • Higher nutrient content can mean higher quality of algae for grazers • Decrease Ca concentration, but unlikely to affect algae in natural system

  41. Overall Conclusions: structure • Not found to be as important as nutrient contributions • No difference among empty shell, pottery shard, or sand alone treatments • Algae were floating in the water • Cladophora bulk biomass was not able to reattach • More attachment with live Dreissena

  42. Implications • Dreissena increased algal biomass of one species and contributed several important nutrients to benthic algae • Supports nearshore shunt hypothesis

  43. Implications • Dreissena increased algal biomass of one species and contributed several important nutrients to benthic algae • Nutrient reduction policies help control algal blooms, but Dreissena aggregate N and P which benefits benthic algae • May promote blooms despite reduced loading • Target nutrient levels may have to be lower than previously believed • Nutrient reductions may be ineffective • Dreissena help benthic algae acquire C • Benthic algae have a low affinity for nutrients in water column

  44. Implications • Dreissena increased algal biomass of one species and contributed several important nutrients to benthic algae • Nutrient reduction policies help control algal blooms, but Dreissena aggregate N and P which benefits benthic algae • Algae can store nutrients • Helpful when nutrient availability is low • Create longer presence of algae

  45. Acknowledgements • Advisor: Dr. Christine Mayer • Committee: Dr. Scott Heckathorn, Dr. Thomas Bridgeman, Dr. Rex Lowe • Department of Environmental Sciences and the Lake Erie Center • Dr. Jonathan Frantz & USDA ARS team at UT • Plant Science Research Center • Lab/Field/Other Help • Mike Bur and Patrick Kocovsky, USGS • Kristen DeVanna, Justin Chaffin, Sasmita Mishra, Dominic Armenio, Sarah Panek, Shellie Phillips, Rachel Kuhanek, Nate Manning, Peter Bichier, Mike Kuebbeler, Todd Crail, Chris Bronish, Sam Guffey, Blake Quinton, Steve Timmons, Jeremy Pritt, Dale Lorenzen III • Funding sources • Lake Erie Protection Fund, SG 384-10 • EPA Lake Erie Algal Source Tracking

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