A Survey of Phormidium Sp. Across An Agricultural Impact Gradient in Central Pennsylvania

Elaine Langone Center, Terrace Room

There has been a recent proliferation of the benthic, mat-forming, filamentous cyanobacterial genus Phormidium in streams and ponds around the world. However, even though the genus is known to produce anatoxins and has been linked to animal deaths, little is known about the specific environmental conditions that lead to its colonization and success. In a recent survey of 19 streams in central Pennsylvania, with varying levels of agricultural impact, we found Phormidium species in six of the streams, in different stages of growth. We took quantitative and qualitative measurements of stream environmental parameters including water nutrients, ecosystem metabolism, nitrogen and phosphorus uptake in portable mesocosms, photosynthetic capacity via pulse amplitude modulated fluorometry, algal cover types, turbidity, and canopy cover. Preliminary results show higher nutrient concentrations, especially nitrates and nitrites in streams where Phormidium sp. were present. Amount of storm nutrient runoff from neighboring agricultural lands may play a role in proliferation, as well as scouring from storm events impacting the ability of mats to colonize.