Use of a simple water column sampler to monitor chemical and biological conditions in shallow waters

Field studies in a shallow lagoon indicated that quantitatively reliable estimates of inorganic nutrients, active phytoplankton chlorophyll a, and copepod nauplii can be obtained with a tube-type sampler. Samples collected in shallow, well-mixed water by a water column sampler (=7.62-cm ID, 4.57 m long, 0.021 m³ capacity – PVC tube) and a discrete-depth sampler (=7.62-cm ID, 0.49 m long, 0.005 m³ capacity – Niskin bottle) were statistically similar. The number of copepod nauplii captured in the tube sampler was significantly greater (ca. 2X) than the densities obtained in a 25-cm ID, 64-µm mesh net.