1. Analysis of Phosphorus forms in Waiteti Stream sediments Jamie Peryer-Fursdon BOPRC Summer Student 2012/2013

2. Study Aims: To look at stream sediment composition and its potential effects on lake degradation Compare stream sediment’s with Dylan Clarke’s detainment bund sediments Specifically look at forms of Phosphorus

3. Sample Sites Detainment Bund Stream sediment sample Stream sample collection: -Sediment Corer, or -Sediment (Ponar) Grab

4. Methods Using chemical analyses to see what elements the P is bound to: either strongly bound- Ca/Al bound bound to redox sensitive elements-Fe/Mn (potentially bio-available) Also equilibrium P concentration (EPC) of sediments

5. P Concentrations Stream sediments have much lower concentrations of P than other sources Stream sediments have much lower concentrations of P than other sources

6. Generally more phosphorus in upper catchment stream sediment

7. Potential Bio-availability Fe/Mn bound P Could be released when deposited in lake sediment

8. Equlibrium P Concentrations SITE19Wai DB Mean DRP 2002- 2009 Waiteti Strm EPC (mg/L)0.0250.0220.1400.042 Stream sediments lower EPC than overlying water Bund sediments much higher EPC than stream water therefore net desorption of P into water contributing to DRP

9. Stream Sediment Low overall concentration Around 30% of P can potentially add to internal loading when deposited into lake. Could be a P sink for overlying water in stream conditions

10. DB sediment Higher potential downstream effects from this sediment Initially net desorption of P from sediment into water-bio available Around 25 % of P still bound to sediment can be released when settled in lake sediments Hence importance of DBs within lake catchment Photo: D. Clarke

11. Acknowledgements: Special Thanks to: Land Owners: Elizabeth Hosking, John Coatesworth, Mike & Rebecca Pethybridge, Murray Scott, T & M Cairns Supervisors: Dr Jonathan Abell, Dylan Clarke, Prof David Hamilton, Alastair MacCormick Others: Dr Deniz Özkundakci, Annie Barker, Steve Cameron, Michael Hupfer, Annette Rodgers Bay of Plenty Regional Council for this opportunity