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Investigation of Salinity at Crystal Cove State Park

by Heather Childress, Alisa Campana, Megahn Wimmer and Ryan Green

Introduction

Salinity is the amount of salts dissolved in seawater.  What processes can change the salinity in the ocean?  Our lab group investigated variations in salinity shore at Crystal Cove State Park.

To examine the variation of salinity we investigated and took samples of the ocean water on September 7,1999, and on September 14,1999.  This paper will show results of change of salinity along the shore at Crystal Cove State Park.

Methods

On September 7, 1999, an overcast and cool morning, beginning at 9:30 in the morning we started out by testing the salinity and temperature of the run-off in different areas (sample 1A-5A).  We started at the top using a hand refractometer to test the salinity and a digital thermometer to take the temperature.  Taking a cup, which was placed on the end of a pole made of pvc pipe, we scooped up a sample of water from each testing point.  Then we put the thermometer in the cup with the water and waited for the reading to stop moving.  Next we poured some of the water on to the glass of the hand refractometer and looked at the reading and recorded it.  We continued this process for all the samples taken at the run-off.

On September 14, 1999, an overcast and cool morning, beginning at 9:15 in the morning we started at the North end of the beach and took samples all the way along the beach to the South end (samples 1-15). Each sample was taken in about knee-deep water. The samples that were taken near the rocks were taken directly next to the rock.  At each sample area we took one sample took its measures then dumped out the water and took a second sample from the exact same area.  We used the same technique to take the temperature and salinity as we did at the run-off the previous week.

The temperature in our table had a greater span because we included our data from the fresh water run-off.  Those points include those labeled 1A through 5A.  The water was much warmer in the run-off compared to the water in the ocean.  Points 1, 5, 8, and 10-13 from both the table and the chart are all the samples near the rocks.  All these samples showed an increase in temperature compared to those samples taken in water not near rocks.  The temperature showed to be warmer over all at the southern end of the cove. At the most Northern end, samples 1-5, the range in temperature was in-between 14.75 degrees C and 15.05 degrees C. Our salinity finding did not conclude that much. Our table shows that the salinity levels in the run-off, sample 1A4A, measure 9.775 ppt. The only variation to that was where the run-off met the ocean. The measurement we got there was 36.125 ppt. This measurement was shown on the table as sample 5A. Along the shore we did not get any differences in measurement except at that same run-off. Along the shore the measurements were 37.185 ppt.  At the run-of the measurement was 36.125 ppt.  This is shown on both the table and the chart as samples 1-13.  The run-off sample is sample number 9.

Conclusion

In studying possible explanations for the temperature change along the shore of Crystal Cove one would hypothesize that the areas near rocks would increase the temperature of the water because of the possibility that rocks contain heat.  If one would want to further study temperature change at Crystal Cove you could examine the temperature of the rock by placing a thermometer on the rock or in the rock to check if rock does indeed store heat.  You could also take many samples around the rock mass in the water and then move out to take more samples; five feet away from rock, ten feet, then fifteen feet to determine if the rocks hold heat.  Possible reasoning for the temperature change at Crystal Cove would be that the fresh water runoff also effects the temperature along the shoreline, because basically the freshwater runoff travels along the sand which absorbs heat too from the sun, as do the rock mass.  If one would want to further investigate the temperature change along the freshwater runoff you could take the temperature of many runoff.  Salinity does not change because the water mass at Crystal Cove is not effected by any other mass of water in the area.  You could further investigate the salinity change by taking samples further away from shore.  

 

Sample

Salinity

(PPT)

Temperature

(C)

1A

9.775

18.2

2A

9.775

18.0

3A

9.775

18.2

4A

9.775

18.1

5A

36.125

18.0

1

37.185

15.05

2

37.185

14.75

3

37.185

14.8

4

37.185

14.85

5

37.185

15.0

6

37.185

14.75

7

37.185

14.8

8

37.185

14.95

9

36.125

15.25

10

37.185

15.3

11

37.185

15.3

12

37.185

15.4

13

37.185

15.55

 

*Table 1: Salinity and Temperature data for Crystal Cove on September 7, 1999 and September 14, 1999.  Samples 1A-5A were taken from the run-off.  Samples 1-13 were taken along the shore running North to South.

 

 

Sample

Date

Time

Location

1A

9-7-99

9:35am

In run-off #2 from the waterfall

2A

9-7-99

9:42am

In run-off #2 from the lagoon

3A

9-7-99

9:55am

In run-off #2 from the upper flow of the stream

4A

9-7-99

10:04am

In run-off #2 from the lower flow of the stream

5A

9-7-99

10:16am

In Ocean where run-off #2 flows in

1

9-14-99

9:40am

Furthest North by large rock masses

2

9-14-99

9:43am

North end Trashcan #1

3

9-14-99

9:45am

North end Trashcan #2

4

9-14-99

9:50am

Run-off #1

5

9-14-99

9:54am

North end Trashcan #3

6

9-14-99

9:59am

Trashcan #4

7

9-14-99

10:01am

Life guard stand #1

8

9-14-99

10:05am

Trashcan #7

9

9-14-99

10:07am

Run-off #2

10

9-14-99

10:14am

South between large rock masses

11

9-14-99

10:16am

South Single Rock

12

9-14-99

10:20am

South end trash can near rocks

13

9-14-99

10:25am

Furthest South in front of large rock mass

 

*Table 2: Date, Time and Location data for Crystal Cove September 7, 1999 and September 14, 1999.  Further information for Table 1.

 

  Figure 1 : Bar chart of salinity values for Crystal Cove on September 14,1999

Figure 2: Bar chart of temperature values for Crystal Cove on September 14,1999