(Solved): Dissolved silicate is considered a biolimiting nutrient in the surface ocean, despite it being the s ...
Dissolved silicate is considered a biolimiting nutrient in the surface ocean, despite it being the second most abundant element in the Earth's crust. It is incorporated into the hard shells of diatoms and radiolarians as amorphous silica. This biogenic silica (BSi) adds significant density to sinking particles. As a result, particles containing BSi may sink rapidly and deliver a surprising amount of Si to the seafloor. BSi may reach the seafloor in significant amounts because of high sinking rates due to balasting by the siliceous tests, diatom aggregations, or their incorporation into zooplankton fecal pellets. The table below presents these three different scenaria. Complete the table to calculate the final amount of BSi originally exported that reaches the deep-sea floor at
5,000m. \table[[Form of BSi export,Free diatoms,Aggregated diatoms,Diatoms in fecal pellets],[Exported [BSil (umol L
^(-1)),80],[Water column depth (m),5,000],[Particle diameter.
d(um),50,250,220],[Particle densitv. ow
(gcm^(-3)),1.4,1.4,1.15],[Sinking rate (
md^(-1))],[Sinking time to reach the seafloor (d)],[Dissolution rate (% d
d^(-1)),6.6 %,2.9 %,
2.5%