DNA-based algae identification methods show promise for stream condition assessments

SCCWRP and its partners have shown in a proof-of-concept study that DNA sequencing methods have the potential to be incorporated into algae-based assessments of stream condition.

During the multi-year study – scheduled to be completed by the end of 2019 – researchers compared traditional, morphology-based identifications of stream algae to DNA-based identifications of the same samples.

Although the two methods often identified different consortia of algae species, both methods consistently distinguished among stream sites in poor vs. good ecological health. The DNA-based approach also was able to identify hundreds more algae taxa than traditional microscopy-based taxonomic identification, underscoring the potential value of metabarcode sequencing.

Based on the findings, stream managers plan to continue DNA-based algae identifications in California as part of routine condition assessments using the Algal Stream Condition Index scoring tool. The additional algal DNA data will help researchers further refine and optimize this alternative approach for conducting algae-based stream bioassessments in California.