Bioturbating Invertebrates Enhance Nitrogen Cycling in Lake Ontario Coastal Stormwater Ponds

Session: Poster session

Kerry Kuntz, Rochester Institute of Technology, [email protected]
Anna Tyler, Rochester Institute of Technology, [email protected]

Abstract

Stormwater retention ponds manage runoff in developed areas of the Great Lakes watershed, reducing flooding and erosion, and improving downstream water quality. Urban ponds also serve as habitat for aquatic organisms in an otherwise terrestrial habitat.  However, the relationship between common pond species, biogeochemical function, and the implications for water quality is poorly understood.  Using a microcosm experiment, we evaluated the influence of two bioturbating invertebrates, Chironomus sp. and Lumbriculus variegatus, on sediment-water column nutrient exchange and benthic metabolism in stormwater ponds of the Lake Ontario watershed. Both organisms facilitated net release of reactive inorganic nitrogen to the water column, flipping the net reactive nitrogen balance of sediments relative to controls. Release of ammonium and sediment oxygen consumption were enhanced by both species, especially during colonization, but sediment uptake of nitrate was strongly enhanced by Chironomus and inhibited by L. variegatus.  There was no measurable impact on phosphorus fluxes.  After 30 d, context specific interactions appeared, indicating the role of landscape and management in mediating biodiversity-ecosystem function relationships.   This study illustrates the important role of tolerant benthic invertebrates in mediating ecosystem functions in even the most disturbed aquatic ecosystems, and altering nutrient stoichiometry in waters entering the Great Lakes.  

1. Keyword
benthos

2. Keyword
watersheds

3. Keyword
nutrients

4. Additional Keyword
stormwater

5. Additional Keyword
biodiversity-ecosystem function