Arbutus Lake Overview by: Leah Taylor & Robert Owen December 7th, 2006 EFB 525

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

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

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

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

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: 15.31 um

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.

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

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