A Limnological Assessment: The Lucas Pond

1. A Limnological Assessment: The Lucas Pond Christian Brown Dylan Gollen Taylor Lasley John Novak

2. Overview • Objectives • Methods and Materials • Results • Discussion • Implications

3. Team Objectives Sediment Analysis Macro Invertebrate Assessment Identify species present Enumerate densities • Water content • Organic matter

4. Methods and Materials Field Equipment Lab Equipment Digital scale and weigh boats Oven Metric ruler • KB Core sampler • Ekman grab sampler • Pencils, notebook, tape • Storage containers

5. Methods and Materials Sampling Design • KB core and Ekman samples were taken in a balanced manner that encompassed the greatest area of the pond • Seven samples total for each sampling method • Two samples from east and west sites • Three replicates from middle site

6. Methods and Materials

7. Methods and Materials Analyzing KB Core Samples Water Content • measured total core depth (cm) • removed 1cm sections • recorded wet weights of each section • placed samples in oven, then recorded dry weights Percent Water Content = Wet weight-dry weight/wet weight

8. Methods and Materials

9. Methods and Materials Organic Matter • Placed dried samples into oven for burning • Recorded ash weight Percent organic matter = dry weight – burn weight/ dry weight

10. Methods and Materials Benthic macro invertebrates • collected with Ekman grab sampler • Same sample sites • Samples filtered through wash bucket (remove sediment) • samples were stored and preserved in ethanol solution • species identified and enumerated using dissecting microscopes • densities were converted from Ekman volume (225cm2) to number per square meter

11. Results

12. Results

13. Results

14. Results

15. Discussion Sediment Accumulation • Pond size • Steep catchment • Surrounded by granitic Gneiss rock • Allocthonous inputs from vegetation and rock

16. Discussion Benthic Macro-Invertebrates • Relatively high abundance • Chaoborus, Chironimids, and Oligochetes contribute to bioturbation(Ademek et al. 2009) • Mechanical mixing of sediment through construction of feeding tubes and burrows • Affects transport of nutrients, particularly P and N • Increases oxygen penetration into sediment which enhances mineralization process by which nutrients are released into the overlying water • Inhibition of phytoplankton and benthic macrophyte growth • Chironomid larvae can increase nutrient enrichment which can eventually lead to eutrophication

17. Implications • When considering the benthic aspects of the Lucas pond the longevity is dependent upon: • High rates of total sediment and organic matter accumulation • Unchecked population of benthic macro invertebrates could diminish pond water quality through process of bioturbation

18. Literature cited • Ademek, Z. Marsalek, B. 2013. Bioturbation of sediments by macroinvertebrates and fish and its implication for pond ecosystems: a review. Aquaculture Int. 21:1-17 • Brainard, A. S. Fairchild, G.W. 2012. Sediment characteristics and accumulation rates in constructed ponds. Journal of Soil and Water conservation. Vol. 67, no. 5. pp. 425-432

19. Questions