Sampling & Analysis

Overview

The Biological Monitoring Program evaluates the health of the State's streams, rivers, and wetlands based on the types and numbers of aquatic organisms present to determine if they attain water quality goals and standards established in Maine law. In 1986, the Maine State Legislature adopted Maine's Water Quality Classification Program statute which assigned one of four classes (AA, A, B, and C) to every river and stream segment in the state. Lakes and ponds were assigned to a single class (GPA).  Wetlands associated with rivers, streams and GPA waters were assigned the same class as their associated waterbody. Each water quality class has different environmental goals along with standards and criteria to support those goals and determine if they are being attained. A major goal is to support healthy communities of aquatic life. The Biological Monitoring Program collects samples of macroinvertebrates (aquatic insects, crustaceans, mollusks, mites, leeches, and worms) and algae to determine if waterbodies are attaining aquatic life criteria associated with their assigned classes (AA, A, B, C, or GPA).

Macroinvertebrates and algae are excellent indicators of water quality. The number of different kinds of organisms and the abundance of different groups provide information about a waterbody's health. Some species or groups require cold, clean water and natural habitats. Other species or groups can survive in warm, polluted water and degraded habitats. Since macroinvertebrates and algae live in bodies of water, they are exposed to environmental conditions over a period of time. The resulting communities of macroinvertebrates and algae reflect the overall health of a waterbody.

The Biological Monitoring Program has a long history of using macroinvertebrate data to determine if streams and rivers are attaining the aquatic life goals assigned to them. The Program uses a statistical model based on biological variables such as the number of different kinds of macroinvertebrates or the abundance of specific groups that require cold, clean water. The model predicts the probability of a stream attaining aquatic life criteria for class AA/A, B, or C. The Biological Monitoring Program has also developed similar models for macroinvertebrates in wetlands, and for algae in streams and freshwater wetlands. In addition, the Program has developed standard survey methods and biological metrics for aquatic plant communities (macrophytes) to characterize wetland habitats and evaluate their ecological health.

The Biological Monitoring Program also collects supporting data including watershed land-use and land cover, habitat condition, water chemistry, and potential environmental stressors at sites where biological communities are sampled.  This information is helpful to identify causes and sources of environmental harm and determine how to restore an impaired waterbody.

The links below describe biological sampling and analysis in more detail. For additional information on this subject please see the Biological Monitoring Program's Standard Operating Procedures, located on the Materials Page.

Algae Types Descriptions of the different kinds of algae.
Algae Sampling In Rivers & Streams Sampling and data analysis methods for algae in rivers & streams.
Algae Sampling In Wetlands Sampling and data analysis methods for algae in wetlands.
Macroinvertebrate Types Descriptions of macroinvertebrate orders.
Macroinvertebrate Sampling In Rivers & Streams Sampling and data analysis methods for macroinvertebrates in rivers and streams.
Macroinvertebrate Sampling In Wetlands Sampling and data analysis methods for macroinvertebrates in wetlands.

Click on a map to view a larger version (pdf file).