Results from the Rope Assay:

Multivariate Analysis of the results for the three RopeAssay Experiments are shown for the three incubation depths (0.5, 1.0, 1.5m) with circles indicating the farthest downstream (blue) and upstream (red) stations. There is no significant effect of water quality in North River on Zostera growth as indicated by the high degree of overlap of the two stations, and the lack of clustering by depth of the response variables. The variables used in this Principle Components Analysis were: #shoots, # leaves, longest leaf length, Fv/Fm = photosynthesis yield ratio, leaf plastochrone interval (PI-Leaf), biomass and area of new leaf tissue grown during the two week incubation. The PCA was done on the centered and standardized data, PC1 explains 50.8% of the variability in the data, and the dominant eigenvector is that explained by # leaves. The second PC explains an addition 17% of the variability with the heavily dominant eigenvector being Fv/Fm. PCA suggests therefore that the majority of the variability in the data can be explained by these two variables (#leaves, Fv/Fm) and these will be used in subsequent experiments.