a limnological assessment: the lucas pond
DESCRIPTION
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 - PowerPoint PPT PresentationTRANSCRIPT
A Limnological Assessment: The Lucas PondChristian BrownDylan GollenTaylor LasleyJohn 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 MaterialsSampling 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
Methods and Materials
Analyzing KB Core SamplesWater 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
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 MaterialsBenthic 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
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, 2013.Sample t df n p Organic Matter (%) 3.412224599 9 10 0.007722 Water Content (%) 13.55686461 9 10 2.71E-07
Results
Sample t df n pBenthic Macro -2.178199633 2 3 0.080636
Table 2. Paired t test between benthic macro invertebrate counts from the east and west sampling sites in the Lucas
pond on October 9, 2013.
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. 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
QUESTIONS