【国外标准】 Standard Practice for Sampling Phytoplankton With Depth-Integrating Samplers (Withdrawn 2020)

4.1 The advantages of the depth-integrating samplers are as follows: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 The disadvantages of the depth-integrating samplers are as follows: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 There are several special considerations that shall be observed when using depth-integrating samplers. They are as follows: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.1.1 This practice covers the procedures for obtaining quantitative samples of a phytoplankton community by use of depth-integrating sampler. The method is suitable for use in flowing waters.1.2 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.