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patrickbdevaney
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mia9

Dataset card Data Studio Files
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statistical software). In summary, our final model included ten
biogeochemical parameters (TOC, TN, TON, TP, SRP, CHLA, NOx, NO2-
, NH4
+
,
salinity, turbidity, and DO), four statistics (mean, standard deviation, median and
median absolute deviation) for the five retained Principal Component scores.
Final results of hierarchical clustering are shown in the dendrogram (cluster tree)
of Fig 3.2 for eight water-classes. Using the cluster tree output from MINITAB-16® we
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analyzed the progression of subdivisions by sliding a threshold level along the statistical
distance axis and plotted the resulting clusters as coded maps to visualize such
progression. An example of this process is provided in Figure 3.3, depicting the
progression of BB clustering as statistical difference declines. The 3-cluster
arrangement separates waters from the southernmost bays (Barnes and Manatee;
blue), the most exposed stations to oceanic influence in central bay (light blue), and
those with strongest influence from land sources (brown). Progressive disaggregation to
5, 7 and 8 clusters reveals the persistence of the E-to-W gradient resulting from water
exchange and the development of a N-to-S pattern. This superimposed trends seem to
reflect both, circulation and differential impact from land sources, in turn linked to
changes in urban development (larger in North Bay) to agricultural areas (larger in
South Central) to mostly un-habited wetlands at the southern extreme. The 7-cluster
results for Central Bay and Card South are exactly the same as those of Caccia and
Boyer (2005).
Figure 3.2. Cluster tree showing water classes for Biscayne Bay (NOTE: Observations
along the x-axis are not station numbers)
The purely biogeochemical-statistical classification of Biscayne Bay waters into 8
water classes was partially modified by incorporating additional water circulation and
geomorphological criteria, as well as location and distribution of canal outlets. This
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modification was required for structuring the box-model calculations, which only
included stations in Central and South Biscayne Bay (from Rickenbacker Causeway to
Manatee and Barnes Sound). Modifications for the box-model were as follows: (1)
Station 103 (from cluster 4) was incorporated to the South Central Inshore segment (to
cluster 3); and (2) Station 129 (from cluster 7), just south of Rickenbacker Causeway
was clustered together with Station 126 (from cluster 5) to make a new cluster, NorthCentral Inshore (NCI)
Figure 3.3. Cluster evolution of Biscayne Bay. The 3-cluster arrangement shows the
fundamental subdivision of bay waters. Progressive clustering tracks the development
of two gradients in water quality, E-to-W and N-to-S
The resulting segmentation after taking these changes into consideration is
shown in Fig. 3.4, where the clusters are:
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3 clusters 5 clusters
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7 clusters
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