Assessing the Nation's Rivers

Following is text from an article printed in the Waterline newsletter (Vol. 2, No. 1, April 2000), a publication of the Patrick Center for Environmental Research of the Acadmy of Natural Sciences

Patrick Center scientists use algae to monitor water quality

To many people, "algae" are the slippery green and brown growths they see covering the bottoms of nearby streams and rivers. Despite their cryptic nature, algae, which include a diverse collection of photosynthetic organisms, are fundamental components of freshwater aquatic ecosystems. As primary producers, they are a major source of energy for many benthic invertebrates, fish, and ultimately larger consumers in the food web such as birds, bears and people. Because of their intimate and continuous contact with the water, algae are also very useful indicators of overall water quality. For all these reasons, the U. S. Geological Survey includes algae as one of the primary biological indicators for its National Water Quality Assessment Program (NAWQA).

USGS and the Patrick Center

In the past year, the USGS and the Patrick Center for Environmental Research have established a $2.1 million, four-year cooperative agreement. Patrick Center scientists will analyze algal samples collected by USGS biologists and integrate this information with chemistry, fish, insect, and geomorphologic data taken by NAWQA scientists. The Patrick Center effort will contribute significantly to understanding water quality issues nationwide, while emphasizing the importance of algal distribution and ecology.

The NAWQA program is the largest federal effort to date to monitor and assess the conditions of rivers and streams throughout the United States. Nearly 60 major watersheds are being evaluated, representing 70% of the nation's drinking water. The goal of NAWQA is to provide continuous water quality assessments that identify and describe major water quality issues. The results of the program will serve as the basis for understanding watershed ecosystems nationwide, and for solving serious water quality problems. To this end, USGS research staff are measuring a wide variety of water chemistry parameters and physical habitat characteristics, in addition to identifying fish, benthic invertebrates and algae. Data are analyzed on the watershed scale and also on a national scale. At the watershed scale, the focus is on water quality issues pertaining to a particular watershed. National scale syntheses address broader issues such as the distribution and concentration of pesticides among watersheds.

Patrick Center scientists have been analyzing NAWQA algal samples since 1994. Under the new four-year cooperative agreement, the PCER role has been expanded to include data synthesis and interpretation, as well as the preparation and analysis of about 500 samples per year. The Patrick Center subcontracts the analyses of some of these samples to other phycology centers, primarily Dr. Jan Stevenson's lab at Michigan State University.

All samples are collected from the surface of rocks and other natural substrates, then preserved and shipped to Philadelphia. Subsamples of soft-algae, which include green, red, and blue-green forms, and diatoms are processed in the Diatom Laboratory. Accurate identification of algae is rigorously documented with photographs taken through state-of-the art microscopes. After the samples are analyzed, they will be stored at the Academy for future reference. The diatom slides will be a major addition to the Academy's Diatom Herbarium, already the largest in North America and a major resource for the scientific community.

Patrick Center Phycologists at Work

The algal and diatom analyses are performed by the Patrick Center's Phycology Section, led by Dr. Donald Charles. Frank Acker helps manage the program and analyzes the majority of the non-diatom (soft) algae. Todd Clason and Lont Marr identify diatoms and soft algae and are also involved with diatom imaging and analyses. Candia Knowles is the Laboratory Manager, responsible for managing samples and data, coordinating schedules, and tracking budgets. Patrick Cotter manages the project databases and creates sophisticated computer applications. Heidi Brabazon runs the sample preparation laboratory. Dr. Marina Potapova, a new Postdoctoral Associate, will organize and analyze diatom ecological data. Dr. Carol Couch, leader of the NAWQA Ecological Synthesis Project, coordinates the cooperative agreement for USGS and the integration of all ecological data at the national level. Stephen Porter, also with USGS, was the major force promoting algal analysis within NAWQA. He will help to coordinate algal data generation and interpretation.

What’s Next?

The data will be used to calculate and evaluate various water quality indicators such as the number of different kinds of algae, their diversity, percent abundance of most common forms, percent blue-greens, biovolume, etc. The results will allow researchers to better understand algal distribution and abundance across all the watersheds. These results will be included in NAWQA summary reports to be released later this year. Patrick Center and NAWQA scientists will integrate the extensive algal data with NAWQA water chemistry and habitat data in an effort to quantify the ecological characteristics for individual algal forms. The data will be used to identify new algal water quality indicators and to develop strategies for using them to interpret existing data on watershed and national scales. A major focus will be on quantifying the relationship of algal cell volume and community structure to nutrient concentrations and watershed land-use characteristics. It is important to know both the quantity of algae supported by a given level of nutrients and how those levels influence the species composition of algal communities. This information can ultimately be used to help EPA set national nutrient standards. By continuing to monitor changes in algal communities over time, it will be possible to detect changes in nutrient concentrations and their influence on aquatic ecosystems.

The algal data being generated through this cooperative agreement, along with previous NAWQA programs, will constitute the largest algal ecological data set ever developed in terms of geographical extent and diversity. There is great potential for increased understanding of basic algal ecology, as well as the development of new approaches for using algae to monitor water quality. Our participation in this project continues the Patrick Center's tradition of national leadership in the environmental sciences.

For more information on the NAWQA monitoring program visit their web site.