Materials and Methods

     The study was primarily conducted in the high intertidal zone.  Some samples were taken in the mid and low intertidal zone, but the main focus of the study was in the high intertidal zone.  Three trips were made to Nahant, MA, once in late September and twice in early Novermber.  During each trip, the following instuments were utilized:

     A total of 45 samples were taken at random throughout the high and mid intertidal zone around the coast of the Marine Science Center.  The specific intertidal area that was covered in this study is highlighted on the map (Map 1).  A number of different factors were analyzed and recorded in this study including:  the slope of the rock, the direction the rock faces, it location in the intertidal zone, the temperature of the rock, the average size of the barnacles within the quadrat, and shape of the rock.  The slope of the rock was measure using a bar level and a protractor.  A rock face of 0° was defined as a rock that was level horizontally and faced the sky.  A rock of 90° was defined as a vertical rock face, and any rock face that was facing down towards the ground, was defined as greater than 90°.  The direction of the rock face was measured by using a compass.  During the second and third trips to Nahant, a compass was not available, so the directions were approximated using the know directions of North, South, East, and West.  The location of the barnacle masses were defined in two different ways.  First, the location of the masses in the intertidal zone (low, mid, or high) was recorded.  Since all the research was conducted at low tide.  Any barnacles between the water line and 2 feet above it were defined as in the low intertidal zone.  Barnacles between 2 and 5 feet above the water line were defined as in the mid intertidal zone.  Finally, any barnacles above 5 feet from the water line, were defined as in the high intertidal zone.
    The exposure of the barnacles (shelter/exposed) to the open ocean was recorded on a scale from 0-10.  A barnacle mass that was exposed to open ocean and had high wave action, with no barriers between the barnacle mass and the waves was defined as a 10.  A barnacle mass that was completely sheltered from the open ocean and recieved little or no wave action was defined as a 0.  Furthermore, the temperatures of the rock faces were recorded using a UV Thermometer.  However, it is important to note that the temperatures varied signicantly on each trip to Nahant, making it difficult to draw any definate conclusions from because the first set of data was taken nearly two months prior to the other two.  The average size of the barnacles within the quadrat was determined by measuring seven barnacles within the quadrat at random with a digital caliper and taking the average.  The density of the barnacle masses was determined by counting the number of barnacles in each quadrat and multipying that number by the average size.  The number of barnacles was counted using microsoft paint.  The live barnacles were labeled green and the dead barnacles were colored red (figure 2).  Finally, the surface shape of the rock was recorded as either smooth, rough, or smooth with cracks, to determine if barnacles prefer growing on a particular substrate.