A graduate student filtered a liter of seawater using a Millipore filter membrane of 2 $\mu$m pore size. Which of the following is true about her filtrate?
A) It is sterile.
B) Microplanktons are present.
C) It contains picoplanktons.
D) It contains nanoplanktons.
E) None of the above.

Question

Quizplus · Accepted Answer

The Millipore filter membrane used has a pore size of 0.2 micrometers, which is small enough to capture most bacteria, but not small enough to capture picoplanktons or viruses. Therefore, the filtrate is likely to contain picoplanktons, so choice C is the best answer. The other choices cannot be determined just by knowing the pore size of the filter membrane.

A Graduate Student Filtered a Liter of Seawater Using a Millipore