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Fall 2010 Multiple Stressors PI Workshop

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  1. Fall 2010 Multiple Stressors PI Workshop Wayne State University Donna Kashian, Vijay Kannappan, Hunter Oates, Carly Collins Experimental work CILER Tom Johengen, Ashley Burtner, Sander Robinson x

  2. Water Quality Group Top Management Objectives • Predict and manage: • - muck deposition on beaches & • - E. coli/pathogens outbreaks • Identify management efforts or policy changes • that would reduce the impacts of contaminants • (i.e. dredging of hot spots) • Manage sediment loading • Manage and understand the impacts of agriculture • in Saginaw Bay (i.e. nutrient loads, sedimentation, E. coli)

  3. Water Quality Group Primary Knowledge Gaps • What are the primary drivers of muck deposition on beaches? What is the composition of muck? • What and where are the primary sources of pathogens? Are there pathogens in the muck? • What are the impacts of contaminants to water quality? • How much is sediment loading contributing to nutrient loading? • What aspects of agriculture impact water quality & what can be effectively implemented to mitigate impacts?

  4. 2010 Project Overviews and Results • Determine the prevalence, persistence and proliferation of E. coli and enterococci in muck • Assess the physical and biotic influences on internal phosphorus loading in Saginaw Bay • Identify Hexagenia benthic habitats

  5. Fecal Indicators in Beach Muck • Objective 1 : Field Survey • Determine the prevalence of E. coli and enterococci in two different types of muck deposits (dry vs. wet) Objective 2: Laboratory Mesocosm Study Asses the influence of environmental variables on the persistence and proliferation of E. coli and enterococci. • light • temperature • moisture


  6. Prevalence of E. coli and enterococci in wet vs. dry muck deposits Most probable number (MPN) per gram Dry Muck Wet Muck

  7. Effects of temp. & moisture on fecal indicators E. Coli Enterococci Most probable number (MPN) per gram E. Coli Enterococci Days Top panels hydrated: Bottom dry heat

  8. Enterococci E. Coli Most probable number (MPN) per gram Days of exposure to sunlight Cold Storage at 4°C E. coli and enterococci survived in muck over 5 months at 40C Direct sunlight inhibits growth Muck provides a suitable environment for fecal bacteria to persist and proliferate for extended periods under natural conditions. MAY CONTRIBUTE TO BEACH CLOSURES

  9. Assess the physical and biotic influences on internal phosphorus loading in Saginaw Bay Michigan. Objectives 1) Determine the role of sediment flux in phosphorus availabilityunder aerobic and anoxic conditions. - Characterize the sediments-nutrients/carbon/particle size - Identify “hot spots” of P recycling in the Bay 2) Determine the role of dreissenid mussels in nutrient cycling and availability. Zebra Quagga

  10. Hypothesis H1: Under anoxic conditions sediment bound phosphorus will resuspended and become more available. - This phenomenon will be greater in depositional zones H2: Dreissenaexcrement will contribute to phosphorus loading

  11. Sampling sites • Site 5 • Sandy, mussel beds, • macrophytes • depth = 3 m • Site 10 • Silt, loose depositional basin; • depth = 12 m • Site 14 • sand-pebble substrate; • depth = 5 m 10 5 14 (Woods 1964)

  12. Methods: Hypoxia experiments • Sediment cores collected by divers and incubated under ambient temperature & light. • Hypoxia simulated by removing oxygen by continuously • purging with helium; aerobic cores bubbled with air • Nutrients monitored daily (10 days) Treatments anoxic aerobic 5 +O2 - O2 Site 10 + O2 - O2 14 + O2 - O2

  13. Results: Sediment Characterization Site 5 10 14 Textural Class Sandy Clay Loam Clay Loam Sand Bulk Density (g/cm3) 1.66 0.72 1.77 Pore Space (%) 47 72 34 Iron (ppm) 96 178 50 Capillary Pore Space 42% 67% 10% Water holding Capacity (1/10 Bar) 25% 93% 5% Have this data for sites 1,7,11, 13,16, 20

  14. Results : Influence of hypoxia on P availability TDP - aerobic TDP - anoxic 80 12 P (µg P/L) 10 60 8 40 6 20 4 2 0 0 SRP - anoxic SRP - aerobic 140 140 120 120 100 100 80 80 P (µg P/L) 60 60 40 40 20 20 0 0 1 2 3 4 5 6 7 8 9 10 1 2 3 4 5 6 7 8 9 10 Time (Day) Site 14 Site 10 Site 5

  15. Surface vs bottom TP – avg for 2008-10 SB20 SB10 SB5 SB14 SB2 SB10 – 12m

  16. 2009: Influence of hypoxia on P availability (Validated with 2010 data) SRP Flux Values 3500 2500 Average P Fluxes 1500 500 0 800 -500 P Flux (µg P/m2 day) 400 P flux (µg P/m2 day) TDP Flux aerobic 0 2500 anoxic -400 1500 aerobic anoxic 500 0 -500 SRP -1500 TDP 5 10 14 Location (Site)

  17. Summary/Conclusion • Internal loading of P from sediments in Saginaw Bay likely to occur under hypoxic conditions. • Majority of P returning from sediments occurs in sediment type observed at Site 10. Prediction and modeling of anoxia in Bay waters may lead to better forecasting of nutrient loads.

  18. Effects of dreissenid excretion on P recycling • Cores were collected in same manner as experiment 1 • site 5 only • nutrients monitored daily • Dreissena excretion was collected and applied (27μg/L/core) as a treatment Treatments anoxic aerobic + Dreissena Excretion (DE) +O2 + DE - O2 + DE + O2 No inputs - O2

  19. Dreissenid Excretion Impacts 200 0 -200 P Flux (µg P/m2/day) aerobic DE -400 aerobic control -600 anoxic DE anoxic control -800 -1000 TP TDP SRP

  20. Excrement Degradation Timescales Bacterial Conc’ in cores • Incubation of water amended with excrement (no sediments) • Suggests water column process at work (Bacterial uptake?) CFUs/ 100 µL Excrement amended Control

  21. Effects of dreissenid excretion on P recycling • The presence of dreissenid excretion results in less phos. in the water column under anoxic and aerobic conditions (over 10 days). • Excrement degradation experiment showed P removal in oxic filtered river water. • Bacterial counts were significantly greater (p <.001) in cores amended with dreissenid excretion

  22. Hexagenia hatch 2009 Hexagenia mayfly hatch in Tawas, Michigan, July 2009

  23. Hexagenia nymph sampling (June 21-24, 2010) • Collected using 4in diameter cores • - Where possible, established 100 ft parallel transects 4-5ft from embankments; one sample collected every 20ft • - Invertebrates quantified at the lab • ONLY 3 nymphs FOUND, all in Big Creek

  24. Hexagenia adult sampling (June 22-24) Tawas Pier, Tawas City Park, Tawas gas station - Circular quadrants were placed over non-reflective white material and positioned under local street lamps • - Hexagenia were counted inside each quadrant every 10 min from 10:00 pm-12:00 am Locals reported seeing larger swarms the previous week

  25. Acknowledgements Thanks to our divers and ship captains: TaneCasserley, Russ Green, Tom Joyce, Wayne Lusardi and Jack Workman Funding: NOAA Center for Sponsored Coastal Ocean Research

  26. Effects of dreissenid excretion on P recycling 100 Ex 1:TDP & SRP Fluxes 0 -100 TDP Flux -200 80 40 P Flux (µg P/m2/day) 0 50 -40 0 -80 TDP Aerobic SRP Aerobic -100 SRP Anoxic TDP Anoxic -200 SRP Flux Aerobic DE Anoxic DE Aerobic Control Anoxic Control