Acid mine drainage (AMD) impacts ca. 16,900 km of streams in the Appalachian region, but little is known about the biology of these habitats. Typically these habitats have low primary productivity most likely due to metal stress. However, these streams are also very low in nutrients. Traditionally, nutrient limitation studies of periphyton have been conducted employing terracotta pots. Recently, research has concluded that this methodology may have inherent flaws due to variable porosity. Therefore, development of new nutrient diffusing substrates is needed. To test a new approach for nutrient diffusion, petri dishes were filled with agar and the nutrient of choice. A Whatman glass microfiber filter (GF/F) was attached to the top of the dish, which served as the medium through which the nutrients diffused and as a uniform surface area for periphyton colonization. Before testing in a stream impacted by acid mine drainage, laboratory studies were conducted to simulate field conditions. The petri dishes readily diffused the nutrients and were durable to the acid conditions. Six replicates with a control, nitrogen (0.5 M), phosphorus (0.5 M), and nitrogen + phosphorus (0.5 M of each) petri dishes were deployed in four AMD impacted streams for the month of February. Samples were analyzed for Chlorophyll a, ash free dry mass (AFDM), and taxa present. The Chlorophyll a analyses showed the phosphorus treatment to be significantly (p < 0.05) greater than all other treatments and the nitrogen treatment was significantly (p < 0.05) lower. However, these trends were not seen in the AFDM results with no difference among treatments detected. Seasonal assessment of this approach is currently underway.

Key words: algae, AMD, nutrient enrichment, nutrient limitation, periphyton