Grading criteria for grading data interpretation part of task

Support data relate to each data sheet is given on the next page. It is recommended that the data interpretation sheet be graded, using a rubric on the data interpretation, and returned to the student 2 weeks prior to deadline for submitting the two written letters.

This information is not to be made available to students.

(Data provided courtesy of Susan Lovelace, North Carolina Estuarine Research Reserve-a cooperative program between N.C. Department of Environment, Health and Natural Resources/Division of Coastal Management and the National Oceanic and Atmospheric Administration.)

TEMPERATURE is measured in degrees Celsius. In December the average ocean temperature is 13.3. The average overnight low air temperature is 4.44.

SALINITY is measured in ppt (parts per thousand parts.)  Ocean water averages 35 ppt. Freshwater is 0 ppt.

DO is dissolved oxygen and can be measured in mg/L.  Ocean water contains 11.0; good river water contains 7.0. An unusually high growth of algae will have lower oxygen levels.

pH is the measure of acidity, 1 is very acid, 14 is very basic.  Ocean water because of the dissolved carbonate minerals it contains tends to resist large pH changes maintaining ocean water at a pH of around 8.  Neutral water is 7.

NITROGEN may be measured as nitrates in parts per thousand parts (ppt).  There should be very little in water.  It can be found in fertilizers and animal waste. An increase causes algae to grow rapidly.  The bacterial breakdown of wastes decreases DO.

FECAL COLIFORMS are indicator bacteria found in the fecal matter of warm-blooded animals. They indicate sewage pollution from animal waste.  It is measured in colonies/100 of water.  Counts higher than 14 will close an area of shell fishing.

PHOSPHATES may be measured in ppt. There should be very little in water.  As phosphate increases algae may grow and form a mat in the water.  When it dies and bacteria decompose the algae, much of the oxygen in the water is used up.

Specific water quality sites, and probable causes for each of the five sets of data are listed on the next sheet.  This support data is to assist performance task grader and should not be available to the students.  five different data sheets were developed to better assure individual work on this task.