## 3 Results
### Multivariate Analysis  
A multivariate analysis approach was performed in order to identify the correlation among sediment and water contamination, biological effects in the laboratory and the pH reduction in seawater caused by CO2. The original variables are represented by three new principal components (Table 4).  
The first three components explained 82.74% of the variance in the original data set. The first component #1 represents a 43.38% of variance and combined the results of Cu and Zn in overlying seawater and in sediment, Zn and Ni in elutriates, and Cr, Cu, and Zn in sediment. The second component #2 explains a 28.56% of variance and linked As, Zn and Ni in seawater, Cr, Cu, and As in elutriate, the increase in the concentration of H\({}^{+}\) protons (pH reduction) and the biological effects (mortalities of amphipods and sea-urchin larval development inhibition), and the third component #3 explains a 10.80% of variance linking Zn in overlying water and the larval development inhibition of sea-urchins.  
Moreover, negative values were found for the diversity, total abundance, and richness at #1 and #3, which indicates correlations among these results. These variables were  
\begin{table}
\begin{tabular}{l c c c} \hline \hline _Variables_ & \multicolumn{3}{c}{**Components**} \\ \cline{2-4}  & **\#1** & **\#2** & **\#3** \\ \hline _Variance_ & **43.38** & **28.56** & **10.80** \\ \hline _Mobility of metals_ & & & \\ As sw & & 0.82 & \\ Cr sw & \(-\)0.65 & & \\ Cr sw & 0.76 & & \\ Ni sw & & 0.85 & \\ Zn sw & 0.54 & 0.48 & 0.54 \\ As elu & & 0.88 & \\ Cr elu & & 0.62 & \\ Cu elu & \(-\)0.45 & 0.37 & \(-\)0.57 \\ Ni elu & 0.84 & & \\ Zn elu & 0.74 & & \\ _Sediment metal concentration_ & & & \\ As sed & & \(-\)0.99 & & \\ Cr sed & 0.99 & & \\ Cu sed & & 0.99 & \\ Ni sed & & \(-\)0.99 & & \\ Zn sed & & 0.92 & & \\ _Toxicity_ & & & \\ Larval Inhibition & & 0.72 & 0.60 \\ Amphipod Mortality & & 0.96 & \\ Acidification (H\({}^{+}\)) & & 0.96 & \\ _Ecological Integrity_ & & & \\ Diversity & & & \(-\)0.84 \\ T. Abundance & \(-\)0.88 & & \\ Richness & & & \(-\)0.87 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Sorted rotated factor of the original variables on the three principal factors. The loading ¿0.4 are highlighted in the table.  
linked as negative due to the form in which the results were represented (as the values of ecological integrity decrease, more effects were found to be correlated with these factors).  
These results suggest that the toxic effects were correlated with the increase in the concentrations of protons associated with the enrichment of CO\({}_{2}\). The results also correlate the toxic effect with the increase in the mobility of some metals (As, Zn, and Ni in seawater and As, Cr, and Cu in elutriate). Furthermore, the larval development of sea-urchin and the diversity and richness of the macro-benthic communities was shown to have also been affected by the concentration of Zn in seawater that was not correlated with the pH reduction.  
Factor scores estimated for each case are represented in Figure 5. This is a clear visualization of the relationship between the components (factors) and the cases (treatments) tested in the study.  
The factors scores showed that the results indicated in the component #2 that were the toxicity effects and the mobility of certain metals were associated with the pH 6.0 in both stations studied. Moreover, a higher influence of the factors #1 and #3 in the CPI station that were related to the contamination of metals in both cases, sediment and mobility, was observed. These results confirmed Table 3 and Figure 4 since significant effects (\(p<0.05\)) were found at pH 6.0 for both stations, and greater effects associated with the contamination were shown for CPI station.