Influences of fathead minnows and aquatic macrophytes on nutrient partitioning and ecosystem structure in two prairie wetlands
Zimmer, Kyle D.; Hanson, Mark; Butler, Malcolm G.; Duffy, Walter G.
published: Jan 20, 2001
ArtNo. ESP141015003004, Price: 29.00 €
Ecosystem structure and sizes of nutrient pools were compared between two prairie wetlands with contrasting food-web configurations, one site supporting a population of fathead minnows and the other fishless. It was hypothesized that the fishless wetland would typify the clear-water state, the wetland with fish the turbid-water state, and that macrophytes, epiphyton, and invertebrates would be the largest nutrient pools in the fishless site, while phytoplankton and fish would be the largest pools in the wetland with fish. Turbidity, water-column sedimentation rates, and amounts of phosphorus and nitrogen in epiphyton, macrophytes, metaphyton, phytoplankton, aquatic invertebrates, fathead minnows, seston, interstitial water, and sediment were assessed in each wetland. Nutrients were apportioned quite differently in these two wetlands. Major phosphorus and nitrogen pools in the wetland with fish were phytoplankton, seston, fathead minnows, and macrophytes, whereas macrophytes, epiphyton, and aquatic invertebrates were the largest pools in the fishless site. These differences likely reflect direct and indirect influences of fathead minnows and submerged aquatic plants. Our results support the hypothesis that low macrophyte abundance and dense populations of fathead minnows favor turbid conditions in deep, semipermanent prairie wetlands.