14 July, 1997


Today I learned how to use the fluorometer to detect the amount of chlorophyll in water samples we took on the cruise. Basically what actually is happening is that the fluorometer sends out a light signal that causes all the pigments in a sample to fluoresce. Then an acid is added that eliminates all the chlorophyll A. The sample is remeasured and the difference between the two is the amount of plant chlorophyll present. Some measurements are harder than others. There are standard solutions to test the accuracy of this method and the method holds up under such scrutiny.

Gathering data such as this is not fast and it requires careful procedure each time (clean test tube, exact amounts, etc.), and it must be done again and again to show a reasonable average. There are actually changes in the data on chorophyll presence throughout the year, so measurements on nearly the same day must be taken for comparison from year to year. Why would the data change during the year? What are some of the things that could cause it to change from year to year?


Besse Dawson

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