Arbutus Lake
Overview by: Leah Taylor &
Robert Owen
December 7th, 2006
EFB 525
Morphology of Arbutus Lake
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Approximately ¾ of a mile long fetch.
Few small islands not pictured on the map may
disrupt the fetch.
A maximum depth of ~ 25 feet.
Was the first lake sampled on the field trip
Raw Data from Arbutus
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Multiprobe readings showed our data in the range
of -.25 meters to 7.19 meters of depth.
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Negative reading above water for calibration.
Temperature data shows the existence of thermal
stratification.
Rest of the data consistent for a stratified lake
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Turbidity, Dissolved Nitrogen and Oxygen
Temp Depth DO
17.81
2.91
17.56
3.95
16.25
4.81
15.42
5.01
13.81
5.34
12.63
5.7
11.87
6.07
11.43
6.37
11.13
6.74
10.84
7.16
Nitrogen
7.49
1.58
6.94
1.5
3.82
4.2
0.31
5.03
0.3
9.21
0.41
9.63
0.29
16.64
0.26
18.16
0.23
20.86
0.2
26.39
Arbutus
Thermocline
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Thermocline ~ Depth at which the rate of decrease
of temperature with increase of depth is the largest
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Found at approximately 5 meters depth.
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Temp changed 2.45 degrees within the span of 1/3rd of a
meter
Below the thermocline there is very
little primary production
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Dissolved Oxygen percentages drop
sharply
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From 3.9 to .31
No mixing
Arbutus:
Secchi disk
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Vanished at ~ 3 meters
Reappeared at ~ 2.8 meters
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These values point to a mesotropic lake
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applied to clear water lakes and ponds with beds of
submerged aquatic plants and medium levels of nutrients
Data agrees
Arbutus:
Chlorophyll
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By Layer:
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Epi: 72.3 ug/l
Meta: 49.3 ug/l
Hypo:150 ug/l
Silica:
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By Layer:
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Epi: 5.62 um
Meta: 3.37 um
Hypo: 15.31 um
Arbutus:
Turbidity
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Turbidity: the measure of water clarity
Water is extremely clear until reaching the
thermocline.
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Jump from values of 1 NTU to 6.3 NTU with 1 meters
depth (NTU = Nephelometric Turbidity Unit)
Due to non decomposed floating organic matter and
increased nutrient and salinity load.
Arbutus:
Zoop
Daphnia Clodocerans
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5 individuals per liter in metalimnion
Calanoid Copepod
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76.25 individuals per liter in epilimnion
Phytoplankton
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Chrysophyta Mallamonas
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Low Abundance
7 individuals
Chrysophyta Microcystis
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4 individuals
Arbutus: Macrophytes
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Nuphar variegata
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Pontedaria cordata
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Bullhead Lily
White Pickeral Weed
Utricularia vulgaris
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Bladderwort