Matthew D. Cacopardo
The Geological, Chemical and Biological Profile of New Haven Harbor
Once the students have made the connection that there is a pollution gradient form the inner to the outer harbor the class will now sample from four parks located in the inner middle and outer harbor to see if there are any trends in geological, physical, chemical and biological entities.
Geological Analysis
Now the real fun begins. At this time trips to the four parks will be planned. You will need at least an hour and half at each site. We will begin by taking samples of sediment at the four different locations within the harbor. Sediment samples will be taken back to the lab and analyzed for physical characteristics. The sediment will be categorized by its size according to the U.S. Department of Agriculture sediment size categories. These samples will be used to compare the information they generated from Activity Four. Are there differences in sediment size in heavily polluted inner harbor from the less polluted outer harbor? With this information we will determine which sediment type carries more heavy metals. You should see fine sediment in the inner harbor and coarse sediment in the outer harbor. Have the students make predictions why there is a greater concentration of metal in the fine sediment as opposed to the more coarse types. Hint: Because the fine sediment has more surface area it allows more metal to bind to its surface.
Chemical Analysis
Students will begin to look at the chemical properties of the water. For the chemical profile dissolved oxygen concentration, phosphates and nitrate concentrations can be determined. Have students record their values in the data sheet provided.
Biological Analysis
We will then look at specie richness and evenness at the different locations within the harbor. Marine invertebrates and macroalgae will be collected using a plot sample method. This procedure randomly selects multiple areas of one square meter. At each plot species will be identified and the number of each individual within the species will be counted. Students will record the numbers in the data sheet provided.
Once a data sheet is completed for each sampling site students will then fill in the Diversity Index Table for all sites on the following sheet provided. Students will then calculate a richness, evenness and a diversity index for each site to determine which site is the most productive. Below is an example of how this is done.
(table available in print form)
s
, number of species = 3
N, number of individuals = 85
R, richness = 1.55
Ds, Simpson Diversity index = Ds = 1- ( 50(49) + 25(24) + 10(9) ) / 85(84) = 0.56
E, evenness = 0.8301
The formulas for R, Ds, and E are as follows:
R =
s
/ log N
Ds = 1 – ( SUM ni (ni – 1)) / ( N ( N – 1))
Dmax = (s-1/s) x (N/N-1)
E = Ds/Dmax
So a Diversity Index takes into account species richness and the evenness of the individuals' distribution among species. Richness can be expressed simply as the number of species. Evenness is expressed by considering how close a set of observed species abundances are to those from and aggregation of species having maximum possible diversity for a given N and
s
.
If we see a significant difference in our data between locations we can then start to discuss if sediment pollution concentrations relate to specie abundance and distribution. My intent in this research project is to solidify the scientific method to young scientists while building a better understanding for a sustainable future. Good Luck.
