Ammonia, phosphate, nitrite and nitrate were analyzed
spectrophotometrically according to Grasshoff (1976).
Settlement of fouling organisms was measured as percent
cover on the front and back sides of each immersed plate using
Dot-grid estimate method (Foster et al., 1991). The outline of a
panel was traced onto a clear transparency sheet and the area
within was marked in a dot grid with all points 1 cm apart. The
sheet was then filled over both sides of each plate and the
number of points with organisms underneath was recorded.
Percentage cover was then calculated by dividing recorded
points by total number of points. The wet weight of fouling
on the plates was measured over interval periods. To prevent
the fouling organisms from dying, the plates were kept in a
large container full off seawater during measurements.