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Data Series 329

Algal Attributes: An Autecological Classification of Algal Taxa Collected by the National Water-Quality Assessment Program

By Stephen D. Porter


Algae are excellent indicators of water-quality conditions, notably nutrient and organic enrichment, and also are indicators of major ion, dissolved oxygen, and pH concentrations and stream microhabitat conditions. The autecology, or physiological optima and tolerance, of algal species for various water-quality contaminants and conditions is relatively well understood for certain groups of freshwater algae, notably diatoms. However, applications of autecological information for water-quality assessments have been limited because of challenges associated with compiling autecological literature from disparate sources, tracking name changes for a large number of algal species, and creating an autecological data base from which algal-indicator metrics can be calculated. A comprehensive summary of algal autecological attributes for North American streams and rivers does not exist. This report describes a large, digital data file containing 28,182 records for 5,939 algal taxa, generally species or variety, collected by the U.S. Geological Survey’s National Water-Quality Assessment (NAWQA) Program. The data file includes 37 algal attributes classified by over 100 algal-indicator codes or metrics that can be calculated easily with readily available software. Algal attributes include qualitative classifications based on European and North American autecological literature, and semi-quantitative, weighted-average regression approaches for estimating optima using regional and national NAWQA data. Applications of algal metrics in water-quality assessments are discussed and national quartile distributions of metric scores are shown for selected indicator metrics.

Table of Contents



Nutrient and Organic Enrichment

Major Ions and pH

Microhabitat Traits

Semi-Quantitative Approaches for Evaluating Algal Species Autecology

Tolerant and Sensitive Species

Objectives and Scope



Indicators of Nutrient Concentrations and Trophic Condition

Indicators of Organic Enrichment

Indicators of pH, Salinity, Specific Conductance, and Chloride Concentrations

Indicators of Microhabitat Traits, Suspended Sediment, and Calcium Concentrations

Calculating Algal Metrics



References Cited

Data Files



1. National algal-metric indicators of nutrient concentrations and trophic condition.

2. Regional algal-metric indicators of nutrient concentrations and trophic condition.

3. Algal-metric indicators of organic enrichment.

4. Algal-metric indicators of pH, salinity, specific conductance, and chloride concentrations.

5. Algal-metric indicators of microhabitat traits, suspended-sediment, and calcium concentrations.

This document is available in Portable Document Format (PDF): 305 KB

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Data files Brief description
Algal_Attributes_v9.txt List of algal taxa with metrics indicating physiological optima or tolerance to nutrients and other water-quality constituents. (Tab-delimited text file; 539 Kilobytes)
NOTE: A question mark (?) appears in the taxon name when it is included as part of the Academy of Natural Sciences of Philadelphia (ANSP) North American Diatom Ecological Database (NADED) identification (ID) coding system.
Algal_Attributes_Nomenclature_v9.txt List of algal taxa linking current (2006) and former names, including associated ANSP NADED ID codes. (Tab-delimited text file; 69 Kilobytes)
NOTE: When both the official ANSP taxon name and the NADED ID code included a question mark (?), a ? appears in the Nomenclature file.

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