ASTM D4135-82(2012)

4.1.1 The samplers provide the only means by which a representative sample of phytoplankton can be obtained from a stream.

4.1.2 The variety of sampler designs result in the availability of a sampler that can be used in virtually all velocities of flow.

4.1.3 Samples of known volumes can be obtained.

4.1.4 A quantitative sample is obtained. Nanno- and ultraplankton are not lost from the sampling device.

4.1.5 Some of the samplers can be used in water up to 55 m deep.

4.1.6 Many of the samplers are light-weight and can be used without auxiliary equipment.

4.2.1 The samplers can be used only in flowing streams having a velocity greater than 1.5 ft³/s.

4.2.2 Some of the samplers are heavy and require the use of auxiliary equipment, such as a crane with hoist.

4.2.3 The collection of samples can be very time-consuming.

4.3.1 The nozzle of the sampler should be inspected periodically for chips, cracks, or other signs of damage and replaced as necessary.

4.3.2 The sample from each vertical profile must be combined with other similar samples in a common container. If the combined sample is subsequently subdivided, it must be thoroughly mixed before doing so.