1. Thad Grant Abu Andrew Kara 12/10/2008 1

2.  Objectives  Methods and Materials  Results & Discussions  Conclusion & Recommendation  Limitations 12/10/2008 2

3. Hypothesis:  There is more sediment accumulation in the deepest region compared to the shallower areas  Macroinvertebrates are more abundant at shallower depths than those in the deeper areas Objectives:  Determination of sediment accumulation at the deeper and shallower regions of the lake; sediment layers and organic matter content will be the key indicators of the comparison.  Determination of macroinvertebrate density at the same regions as described above. 12/10/2008 3

4.  Description of the Baron pond  Sampling techniques  Laboratory analysis Figure 1 map of Baron pond Showing sampling points 11/5/08 12/10/2008 4

5.  We took three K-B corer samples and one Ekman grab from the deepest point (3meters)  We took two other Ekman grab samples and KB-core samples from the shore (1.5 meters) and mid-depth (1.9 meters) 12/10/2008 5

6.  Each determined amount of sample (2 cm) were placed in crucibles.  Samples were dried for more than 24 hours in the drier.  After dry weights were recorded the samples were placed in a muffle furnace to ash the samples 550 ºC for 3 hours. 12/10/2008 6

7. Greatest at the middle (24.33cm), followed by the deepest point (19.33cm), and then the shore (8.89cm) 12/10/2008 7

8. Moisture content was highest for sediment close to shore (73.4%), followed by the middle point (72.0%), and then the deepest (69.6%) 12/10/2008 8 Fig 3: % moisture of sediment samples 11/5/08

9. 12/10/2008 9 Average % moisture at sediment depth for all samples

10.  Factoring in the % moisture, the deepest point might have had more sediment than any other point, based on the assumption that soil aggregates become compacted with less moisture.  Further clarification needed: aggregate stability depends on particle size, OM and moisture content (Haynes et al 2006) 12/10/2008 10 Fig 4 sediment and % moisture of samples 11/5/08

11. Organic Matter was highest close to shore (13.63), followed by the middle (10.37) and the deepest point (9.37) 12/10/2008 11 Fig 5: % OM of samples 11/5/08

12. 12/10/2008 12 Average % organic matter at sediment depth for all samples

13.  More OM contributed to sediment depth at the shore, compared to the other two sampling points  Deposition of OM seemed to follow from the shore to the middle (the second highest), and the deepest point.  OM content is useful in explaining benthic communities in terms of age, redox potentials, faunal presence and abundance, etc. (Mayers, et al. 1998).  Differences in OM at the three depths could be useful in determining the sediment age. This however could be obvious if there is information on the rate of material breakdown. 12/10/2008 13 Fig 6: OM & sediment depth of samples 11/5/08

14.  Chaoborus population increased with depth, the reverse was the case for chironomids  Rivet hypothesis: Each spp has the potential to perform an essential role in the persistence of the community & the ecosystem; some represent a particular functional group (Ehrlich et al. 1998, Covich et al. 1999).  Chaoborus induces morphological change in Daphnia (Hebert et al. 1985)  Availability of food materials govern the distribution of chironomid communities (Saether O.A 1979) 12/10/2008 14 Fig 7 population density of macroinvertebrates at the Baron pond 12/5/08

15.  Sediment accumulation could be greatest at the middle depth (shelf). This might be due to contribution from the piece of land in the middle, in addition to those from the shore  Organic matter is the greatest contributor to the sediment accumulation  Macroinvertebrate community is dominated by Chaoborus, which is greatest at the deepest depth. 12/10/2008 15

16.  Further investigation with replicate samples is needed to insure the precision of our findings  Labels that resist high temperature are recommended, this limited the reproducibility of our samples  The true picture of the benthic community cannot be divorced from the biotic/abiotic factors of the water column 12/10/2008 16

17.  Covich A. P.; Palmer M. A.; Crowl T. A. The Role of Benthic Invertebrate Species in Freshwater Ecosystems: Zoobenthic species influence energy flows and nutrient cycling. BioScience, Volume 49, Number 2, 1 February 1999, pp. 119-127(9)  Hebert, Paul D. N.; Grewe, Peter M. Chaoborus-induced shifts in the morphology of Daphnia ambigual. Limnol. Oceanogr., 30(6), 1985, 1291-1297  Haynes, R. J.; Swift, R. S. Stability of soil aggregates in relation to organic constituents and soil water content. European Journal of Soil Science Volume 41 Issue 1, Pages 73 – 83 Published Online: 28 Jul 2006  Meyers, Philip A..; Lallier-Vergès, Elisabeth. Lacustrine sedimentary organic matter records of Late Quaternary paleoclimates. Journal of Paleolimnology 21: 345–372, 1999. 345 © 1999 Kluwer Academic Publishers. Printed in the Netherlands.  Saether, Ole A. Chironomid communities as water quality indicators Ecography Volume 2 Issue 2, Pages 65 – 74. Published Online: 30 Jun 2006 Volume 2 Issue 2 12/10/2008 17