aquatic mosses were present in the sampling reach, the QMH periphyton sample would be represented by only one sample container containing microalgae.
Samples of macroalgae (A) are collected with forceps or by hand and placed into a sample container. Microalgae are collected by scraping, brushing, or suctioning material
from all periphyton microhabitats present in the sampling reach and placing algal collections from each microhabitat into a separate container. A composite sample of microalgae (B) is prepared by compositing subsamples from the microhabitat collections. When present in the sampling reach, a sample of aquatic mosses (C) is collected with forceps or by hand and placed into a separate sample container.
The composite sample of microalgae (B) is prepared by the equally weighted composite (EWC) method. With this method, equivalent volumes of algal biomass from each microhabitat subsample are composited into a single sample container. For example, if five periphyton microhabitats are present in the sampling reach, equal volumes of biomass from each microhabitat collection are composited into a single sample of microalgae; the EWC sample of microalgae would contain approximately 20 percent of the periphyto n biomass from each microhabitat subsample.
Qualitative periphyton samples are preserved with formalin and are identified with a sample label and with information recorded on the field data sheet (fig. 2). Samples are transported and stored in boxes or containers that protect the samples from expo sure to light. Preserve samples with a volume of concentrated, buffered formalin sufficient to constitute a 3- to 5-percent concentration of preservative in the periphyton sample. A sample label (fig. 3) containing the following information is affixed t o the sample container: site name, site identification number, sampling reach, date, time, name of the person who collected the sample, type of sample, area sampled (for quantitative periphyton samples), subsample information, type and amount of preservat ive, and sample identification number. The sample identification number is a unique 16-character identification code, described later in this document (refer to "Sample Processing and Labeling").
Information concerning the ecological site and sampling procedure is entered on a field data sheet (fig. 2) at the time qualitative periphyton samples are collected. The date, site name and identification number, sampling reach, and sampling team members are recorded in the "Site Information" section. The section on "Related Sampling Activities" provides space to enter benthic invertebrate, fish, water chemistry, discharge measurement, or other sampling activities that co-occur with or immediately precede algal sampling. The "Physical Site Conditions" section is for recording weather condition, water temperature, and stream stage. Data on local weather conditions that might affect sampling, such as percent cloud cover, estimated wind direction and speed, and the type, relative intensity, and duration of precipitation, are entered in the appropriate spaces. Other relevant weather-related conditions are entered in the space provided for "Other." Water temperature and time of determination are entered for the start and finish of the algal sampling effort. Stream stage is recorded if the stream reach is located at or near a USGS gaging station. All times are entered in a 24-hour (h) format. Observations on water clarity and riparian shading are recorded by circling the most appropriate descriptor.