East Pond Data 2008

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 2008 East Pond Secchi

 The following graph shows the East Pond secchi depths taken in two locations. The Secchi depths track at both stations indicating that the lake is well mixed horizontally. The green line at two meters represents the standard secchi depth for algal blooms.  The data used in the graph can be seen in the following:  Secchi depths vs. time.xls



5/3/2008: 

King launched the Colby pontoon boat.  Sampled for nutrients 69.76657 W, 44.5964 N in stream outflow near boat launch, and took a lake profile at Colby A (DEP1). 



Notes
Profile
Colby A
Bottles 4, 5 - 1 meter; 6, 7 - 3 meter; 8, 9 - 6 meter.  Whole samples.
  Colby  A CTD profile
  Colby A
Secchi Depth: 2.67 Meters
  Colby A
Wind calm, light rain



 On 5/3 East Pond is well mixed from top to bottom as illustrated by the uniform temperature and oxygen profiles shown below.   The fluorescence is high in the lake, consistent with the shallow Secchi depth.  The lake is relatively cold, but could warm up quickly with a few warm, sunny days.   Given the shallow Secchi depth, we expect most of the warming to occur in the top 2-3 meters.   Significant rain or wind events will distribute the heat deeper in the lake.



5/14/2008: 

King installed the weather station and sampled Colby A (DEP1) for nutrients and measured O2, T, FL, and pH

Activity Location
Notes
Profile
Colby A
1 meter filtered - 1A
    1 meter unfiltered - 2B
    5 meter filtered - 3C
    5 meter unfiltered - 4D
  Colby  A EP ColbyA0514a.xls
  Colby A
Secchi Depth: 3.5 Meters
  Colby A
Wind calm, sun




 On 5/14 East Pond is generally mixed with a hint of surface warming in the top 0.5 meters of the lake.  The profile was taken at 3 PM so the warming is a normal daily event due to absorption of sunlight.  The Secchi depth has deepened by 0.6 meters to 3. 5 meters in the last 11 days.   This deepening is consistent with the fluorescence profile that shows significantly less chlorophyll in the top 2 meters.


5/22/2008

Colby and UMO groups sampled both East and North Pond.

Activity Location
Notes
Profile
Colby
EP ColbyA0522a.xls
  UMO UMO 522 North and East.xls




 On 5/22 East Pond and North Ponds are  mixed at 15 oC.      The Secchi depth in East Pond has deepened by almost two meters to 5.4 meters in the last 8 days.   This deepening is consistent with the fluorescence profile that shows significantly less chlorophyll above 4.5 meters.  


----


6/6/2008

Colby sampled East Pond and found moorings for temperature sensors.

Activity Location
Notes
Profile
Colby
EP ColbyA0606b.xls
 





 On 6/6/2008 East Pond and North Ponds are  mixed at 17 oC.      The Secchi depth in East Pond is shallower again with a depth of 2.5 meters.   The lake is experiencing a moderate bloom as illustrated by the uniform fluorescence profile.  Oxygen concentrations remain at saturation throughout the water column.























6/10/2008

Profiles at north and south stations.

Activity Location
Notes
Profile
Colby A
Secchi 3.95,  EP061008DEP1a.xls
  Colby B
Secchi 4.2, EP061008DEP2b.xls



East Pond is well mixed with a moderate bloom at both stations.

 Colby A


Colby B

 


6/17/2008

Colby took profiles at north and south station, and found the mooring at south station.

Activity Location
Notes
Profile
Colby A
Secchi 5.25m  EP061708DEP1b.xls
  Colby B
Secchi 5.19m EP061708DEP2a.xls



Secchi depth continues to increase.  The lake is very well mixed and saturated with oxygen. Watch the units on the graphs when comparing dates.

 Colby A


 
Colby B 

 


6/24/2008

Colby took profiles at north and south station.

Activity Location
Notes
Profile
Colby A
Secchi 6.80m  EPcolby6242008sitea.xls
  Colby B
Secchi 6.70m  EPcolby6242008siteb.xls



The secchi depth has increased all the way to the bottom of the lake at both stations.  Oxygen is starting to drop.  Notice the surface warming in the top 0.5 meters.

 Colby A


 
Colby B

 


7/1/2008

Colby took profiles at north and south station, and took images of the benthos of the lake heading east from Colby A.

Activity Location
Notes
Profile
Colby A
Secchi 6.68m  EP070108DEP1a.xls
  Colby B
Secchi 6.70m  EP070108DEP2b.xls



The Secchi depth remained at or near the bottom at both stations.  The lake is becoming stratified at 4.5 meters.  The "colder" deep water prevents mixing of surface water with the deep lake water resulting in reduced oxygen input from the surface.   Sediment oxygen demand is consuming oxygen in the deep water as shown by the significant decrease in oxygen at both stations below 4.5 meters.

 Colby A


 
Colby B

 


7/8/2008

Colby took profiles at north and south station, and took images of the benthos of the lake heading east from Colby A.

Activity Location
Notes
Profile
Colby A
Secchi 5.70m  EPcolby070808DEP1a.xls
  Colby B
Secchi 5.87m  EPcolby070808DEP2a.xls



The Secchi depth decreased nearly a meter at both stations.  The lake is now becoming stratified at 5.5 meters.

 Colby A


 
 
Colby B
 


7/15/2008

Colby took profiles at north and south station.

Activity Location
Notes
Profile
Colby A
Secchi 5.49m  EPcolby071508DEP1b.xls
  Colby B
Secchi 5.45m  EPcolby071508DEP2a.xls




 Colby A

 
 Colby B
 

 

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  1. May 08, 2008

    Anonymous

    Whitney,

    Where was the sample taken?

     Dave Brown

    1. May 15, 2008

      Colby A or DEP1 is located at the deepest point in the lake 300 meters south of the big island.