Spatial and temporal patterns of algae in newly constructed freshwater wetlands

Spatial and temporal patterns of metaphyton, periphyton, phytoplankton, and water-column primary productivity were studied in two 1-ha newly constructed riparian freshwater marshes (one planted with macrophytes and the other unplanted) at the Olentangy River Wetland Research Park at The Ohio State University in Columbus, Ohio, USA. Surface cover and mid-summer biomass of metaphyton, biomass and production of periphyton and phytoplankton, and water-column primary productivity were sampled from July to November 1994. Methods of spatial statistics were used to examine the spatial patterns in surface coverage and mid-summer biomass of metaphyton. Our results showed that for both wetlands, dense mats of metaphyton (up to 86% surface coverage) acted as nutrient “filters” shaping the spatial distribution of nutrients that in turn affected the spatial pattern of metaphyton by limiting the growth at locations further away from inflow. Metaphyton cover was strongly correlated with phosphorus retention and also influenced the spatial pattern of periphyton and water-column primary productivity. There was no significant difference between the two wetlands in the production and spatial distribution of metaphyton and phytoplankton or water-column primary productivity.