1. Arbutus Lake Overview by: Leah Taylor & Robert Owen
December 7th, EFB 525

2. Morphology of Arbutus Lake
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

3. Raw Data from Arbutus
Multiprobe readings showed our data in the range of -.25 meters to 7.19 meters of depth.
Negative reading above water for calibration.
Temperature data shows the existence of thermal stratification.
Rest of the data consistent for a stratified lake
Turbidity, Dissolved Nitrogen and Oxygen

4. Arbutus Thermocline
Thermocline ~ Depth at which the rate of decrease of temperature with increase of depth is the largest
Found at approximately 5 meters depth.
Temp changed 2.45 degrees within the span of 1/3rd of a meter
Below the thermocline there is very little primary production
Dissolved Oxygen percentages drop sharply
From 3.9 to .31
No mixing

5. Arbutus: Secchi disk Vanished at ~ 3 meters Reappeared at ~ 2.8 meters
These values point to a mesotropic lake
applied to clear water lakes and ponds with beds of submerged aquatic plants and medium levels of nutrients
Data agrees

6. Arbutus: Chlorophyll Silica: By Layer: By Layer: Epi: 72.3 ug/l
Meta: 49.3 ug/l
Hypo:150 ug/l
Silica:
By Layer:
Epi: 5.62 um
Meta: 3.37 um
Hypo: um

7. Arbutus: Turbidity Turbidity: the measure of water clarity
Water is extremely clear until reaching the thermocline.
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.

8. Arbutus: Zoop Phytoplankton
Daphnia Clodocerans
5 individuals per liter in metalimnion
Calanoid Copepod
76.25 individuals per liter in epilimnion
Phytoplankton
Chrysophyta Mallamonas
7 individuals
Chrysophyta Microcystis
4 individuals
Low Abundance

9. Arbutus: Macrophytes Nuphar variegata Pontedaria cordata
Bullhead Lily
Pontedaria cordata
White Pickeral Weed
Utricularia vulgaris
Bladderwort