Using Chemistry to Determine Sediment Source in White Clay Creek

1. Using Chemistry to Determine Sediment Source in White Clay Creek Dr. Diana L. Karwan University of Delaware Department of Geological Sciences Stroud Water Research Center White Clay Wild and Scenic Watershed Summit September 25, 2012

2. Research Questions (www.udel.edu/czo) Christina River Basin CZO: What is the net carbon source or sink provided by the Christina River Watershed? My Research: What is the composition and source of suspended material in White Clay Creek? Does eroded mineral material stabilize and transport organic carbon in the fluvial network? (How) does the fluvial transport of suspended material differ based on its composition on seasonal and storm time scales? Photo: Marissa Morton

3. Research Questions What is the composition and source of suspended material in White Clay Creek? Photo: Marissa Morton

4. Approach Sediment Fingerprinting – possible sources Rill Erosion Road Dust (high Zn) Overland Flow (surface soil: high 7Be, C&N reflect plant community) Photo: Marissa Morton Channel Banks (legacy sediments + buried soil horizons, higher Fe) Trail Crossing (animal evidence???)

5. Study Area • Christina River Basin: • Total area: 1440 km2 • 3 main tributaries – Brandywine River, Red Clay Creek, White Clay Creek • Urban, agriculture, and forest land use • Sediment TMDL Brandywine R. • White Clay Creek: • Total area: 277 km2 • Wild and Scenic River for entire watershed • Urban, agriculture, and forest land use • Drinking water supply in areas of PA and DE Red Clay Ck. Photo: Marissa Morton White Clay Ck. Christina R.

6. Approach • Sediment Fingerprinting • Field collection of suspended materials, landscape materials, precipitation • Analyze for several chemical signatures • Use data in a statistical model to determine fraction of stream material from various sources • Particulate Analyses: • Fallout radionuclides (7Be, 137Cs, 210Pb) • C, N, stable isotopes • Mineral surface area • Grain size • Mineral content (elemental and composition) • Microbial community characterization (16S, rRNA, PCR, ITS-DGGE, sequencing) • FTIR • Separate colloids quantification Photo: Marissa Morton • Streamwater Chemistry: • TSS • DOC • Anions + Cations • Others?

7. Approach Field Collection Precipitation for Radioisotopes • Radionuclide Fingerprints • Precipitation delivered • Strong particle surface affinity • All radioactive, so primary method of ‘disappearance’ is decay. • Plant interception not well known (recent source < 30%) • Erosion tracers: • Beryllium-7 (54 days) • Lead-210 (22 years) • Cesium-137 (30 years) • Beryllium-10 (1.3 million years) 7Be 7Be Photo: Marissa Morton

8. Approach Field Collection of Precipitation Photo: Marissa Morton Open Precipitation Stemflow Canopy Throughfall

9. Approach Field Collection! Challenge: collecting enough solid material for all analyses during baseflow and storms 55 gallon barrel and cell-phone-triggered submersible pump for suspended sediment ISCO automatic sampler for 1 L streamwater samples Photo: Marissa Morton Photo: Marissa Morton Pressure transducer for water height

10. Approach Field Collection! float switch turns off pump The “Dial-a-Pump” 55 gal. barrel open source electronics (Arduino) submersible pump 12V marine battery Cell phone

11. Approach Field Collection! The “Dial-a-Pump” Scaled Up: 3 barrels Photo: Marissa Morton

12. Approach Sediment fingerprinting at nested sites in White Clay Creek Field Collection – Locations 1st order – Avondale PA 3rd order – Avondale PA Photo: Marissa Morton 5th order – Newark DE

13. Results - Rainfall Trees Leaves Trees No Leaves No Trees Summer No Trees Winter • No significant difference in concentration per event with canopy when examining a year of data

14. Results – Shallow Soil • Similar 7Be (short lived!) profile in open and forested area • Longer-lived 137Cs shows mixture that occurs in ‘plow layer’ • Signatures of these isotopes in the stream might help tell us about the depth from which erosion and sediment delivery occur

15. Preliminary Results – Source /Suspended Variations

16. Preliminary Results Suspended Material – Storm Collections • Storm collections began 9/30/2010 • 1 large sediment sample per storm • Target peak • For example: 25 February 2011 Photo: Marissa Morton 7Be = 468 mBq/g 7Be = 468 mBq/g 7Be = 468 mBq/g 7Be = 468 mBq/g 7Be = 468 mBq/g

17. Preliminary Results Suspended Material – Storm Collections • Differences noted along storm hydrograph, beginning in April 2011 Photo: Marissa Morton 7Be = 468 mBq/g 7Be = 468 mBq/g 7Be = 468 mBq/g 7Be = 468 mBq/g 7Be = 468 mBq/g

18. Preliminary Results Suspended Material – Storm Collections • August 25 – September 12, 2011 Hurricane Irene Tropical Storm Lee 66 metric tons sediment export 135 metric tons sediment export 54 metric tons In peak event Photo: Marissa Morton 7Be = 468 mBq/g 7Be = 468 mBq/g 7Be = 468 mBq/g 7Be = 468 mBq/g 7Be = 468 mBq/g 7Be = 146 mBq/g 7Be = 147 mBq/g 7Be = 175 mBq/g 7Be = 698 mBq/g 7Be = 205 mBq/g 7Be = 1052 mBq/g

19. Preliminary Results Suspended Material – Storm Collections

20. Preliminary Results – Radioisotope Fingerprinting • 7Be on stream sediment varies between seasons, with higher values in the spring and summer, and within single storms, with higher values generally earlier in a single event. • One year of rainfall data does not show significant differences across seasons or in the presence or absence of a tree canopy. • Does this mean the differences seen in stream material are from differences in erosion and delivery??????

21. O horizon, sediment under anoxic water leaf litter, algae POM from White Clay Creek soil A horizon, river & coastal sediment Rivers draining deserts Increasing C stability Larger, temperate rivers (data from Keil et al. 1997, Mayer et al. 1994, Onstad et al. 2000) desert soil, B-C horizon deep ocean sediment Oxygen exposure times for marine sediments on the Washington shelf & slope and suboxic Mexican margin (data from Hartnett et al. 1998, Hedges et al. 1999, Keil et al. 2004) <1 White Clay Creek POM with published sediment values

22. Preliminary Results

23. Preliminary Results - POM • POM from White Clay Creek is relatively high in organic carbon content. • Organic carbon to surface area ratios closely resemble the surface soil from the land cover types in the catchment – agriculture and forest. • OC and mineral surface area change with season, but their ratio remains constant and characteristic of relatively ‘fresh’ material.

24. Acknowledgements Anthony Aufdenkampe Steve Hicks Dave Montgomery Stephanie Dix Denis Newbold Sara Geleskie Fred Shaw Erika Vazquez Jim Pizzuto Del Levia Adam Pearson Elyse Williamson Rolf Aatlo Julia Marquard CRB CZO work was funded by the National Science Foundation [NSF EAR 0724971] SSH CZO work funded by an NSF EAR Postdoctoral Fellowship [NSF EAR 1144760]