Particulate organic carbon: Sampling variability

Replicate sampling for particulate organic carbon (POC) in the open ocean indicates that at any given position and depth the POC distribution consists of a homogeneous background concentration on which are superimposed occasional small patches containing two to five times as much organic carbon as is present in the background. The 95% confidence limits for a single 5‐liter sample taken solely from the background are ±2.5 µg C liter−1. The size and frequency of the patches may determine the distribution and productivity of the smaller zooplankton.