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Periphyton are primary producers and an important foundation of

many stream food webs. These organisms also stabilize substrata 

and serve as habitat for many other organisms. Because benthic

algal assemblages are attached to substrate, their characteristics 

are affected by physical, chemical , and biological disturbances that

occur in the stream. Diatoms in particular are useful ecological

indicators because they  are found in abundance in most aquatic

ecosystems. Diatom species are differentially adapted to a wide range of ecological conditions. The great numbers of species provide multiple, sensitive indicators of environmental change and the specific conditions of their habitat.

Periphyton analysis provides government and commercial entities the necessary information to make informed decisions about management and restoration of aquatic systems.


BSA offers periphyton analysis using a combination of technical

approaches to meet the client's scope of work and budget. Our

skilled phycologists employ a range of microscopic methods to enumerate

and identify the soft algae and diatoms living attached to submerged substrates. Diatoms can be examined in greater detail using standard Nitric Acid digestion. This technique removes cell contents and provides good resolution, allowing the samples to be examined at high magnifications allowing for species-level identification. Regardless of method, specimens are always identified to the lowest taxonomic level possible, with the goal of identifying to at least the genus taxonomic level where possible. Many projects competed by BSA follow the rigorous NAWQA methods used to describe and quantify the attached periphytic algal community. However, we will customize any analyses to fit your needs and timeline.

BSA has offered acid-digested diatom analyses for over 10 years. During that time period BSA has successfully completed numerous large periphyton monitoring projects with a focus on diatoms and cyanobacteria for clients throughout the entire United States. BSA taxonomists possess extensive knowledge of plankton biogeography

and also have significant experience identifying invasive species in plankton samples. Our trained phycologists have a good library of literature and extensive experience with algal taxonomy

throughout North America. Our data has been

presented at scientific meetings and conferences

and appears in various journal publications.


Our accurate periphyton data can be used in combination with

environmental variables to generate an index of biotic integrity or IBI.

Additionally, a growing area of research is focused on toxin monitoring of benthic cyanobacterial mats. BSA offers identification of potentially toxigenic periphytic cyanobacteria.

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