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

Overview Objectives Methods and Materials Results Discussion Implications

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

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

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

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

Methods and Materials

Organic Matter Placed dried samples into oven for burning Recorded ash weight Percent organic matter = dry weight – burn weight/ dry weight

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 (225cm 2 ) to number per square meter

Results Figure 2.-Plot of water content versus sediment depth for the Lucas pond in Latah Co. Moscow, Idaho USA on October 9, 2013.

Results Figure 1. - Plot of organic matter versus sediment depth, using core sections taken with a KB corer at the Lucas pond in Latah Co. Moscow, Idaho USA on October 9, 2013.

Results Table 1. Paired t-test for organic matter and water content between the east and west sample sites in the Lucas pond on October 9, Sampletdfnp Organic Matter (%) Water Content (%) E-07

Results

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

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

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

Literature cited Ademek, Z. Marsalek, B 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 Sediment characteristics and accumulation rates in constructed ponds. Journal of Soil and Water conservation. Vol. 67, no. 5. pp

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