Suspended sediments (SS; dry mass) and (B) light extinction (Kd) in the Hudson River at river km 150 for the 1987–1994 period. Zebra mussel biomass was high during the last 3 yr (1992–1994). Summer mean values and 90% confidence intervals are shown for each year. (A) Total measured
SS mass is divided into a phytoplankton component (light stippling) and non-phytoplankton (dark stippling). The phytoplankton mass is calculated as chlorophyll a times 100. This conversion assumes a C:chl of 50 and a dry mass:C of 2. (B) Measured (open bars) and modelled (v) light extinction. Modelled Kd is the sum of extinction due to phytoplankton (light stippling) and a residual component (Kres). Note that as Kd increases, light decreases.