How are benthic macroinvertebrates used to measure water quality?

One common biological assessment used to measure the health of streams and small rivers around the world is sampling benthic macroinvertebrates. Benthic macroinvertebrates can be easily sampled in a small stream by wading in shallow water and dragging a handheld net along the bottom.

How do you sample macroinvertebrates?

Sample with a kick net by holding the net frame firmly against the stream bottom and disturbing the substrate upstream (approximately a full arm’s length) from the net with your feet. Dig deeply into the substrate with the heel or toe to dislodge macroinvertebrates from the streambed.

In which part of the stream would you sample for benthic macroinvertebrates?

All riffle and run areas within the 100-m reach are candidates for sampling macroinvertebrates. A composite sample is taken from individual sampling spots in the riffles and runs representing different velocities.

What are benthic samples?

Benthic sampling can be qualitative (a general assessment of the benthic taxa present, possibly with some observations of their relative abundance) or quantitative (an estimate of the numbers [total or by taxa] present so that a statistical confidence interval of the estimate can be calculated).

What do you need to know about benthic macroinvertebrate sampling?

• Three-ring binder book- to store necessary forms used to record and track samples collected at the site. Binders will contain the Benthic Macroinvertebrate Field Data Sheet, Physical Characterization/Water Quality Field Data Sheet, and sample labels. Example forms are provided in Attachment 1.

How are macroinvertebrates used to measure stream health?

Macroinvertebrate Sampling Benthic macroinvertebrates (BMI) are a useful indicator of stream health. BMI are relatively quick, inexpensive, and can indicate the presence (or absence) of pollutants in a water body.

What kind of equipment is used for macroinvertebrate sampling?

Field personnel performing benthic macroinvertebrate sampling are responsible for adhering to the applicable tasks outlined in this procedure while collecting samples. 3.0 EQUIPMENT • D-frame dip net – 0.3 m2″D”-shaped net (500um nytex screen) where the net attaches to a long pole. Net is cone-shaped for capture of organisms.

How long does it take to collect a macroinvertebrate sample?

Macroinvertebrate Sampling. The sampler moves through a reach of river collecting subsamples with a D-net using a 500μm sieve bucket to sort the macroinvertebrates from sediment and other debris. This technique is designed to be rapid so that each subsample takes no more than 3 minutes to collect.