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Nutrient cycling, connectivity, and free-floating plant abundance in backwater lakes of the Upper Mississippi River

River Systems

By:
, , , , , , and
DOI: 10.1127/1868-5749/2013/0080

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Abstract

River eutrophication may cause the formation of dense surface mats of free floating plants (FFP; e.g., duckweeds and filamentous algae) which may adversely affect the ecosystem. We investigated associations among hydraulic connectivity to the channel, nutrient cycling, FFP, submersed aquatic vegetation (SAV), and dissolved oxygen concentration (DO) in ten backwater lakes of the Upper Mississippi River (UMR) that varied in connectivity to the channel. Greater connectivity was associated with higher water column nitrate (NO3-N) concentration, higher rates of sediment phosphorus (P) release, and higher rates of NO3-N flux to the sediments. Rates of sediment P and N (as NH4-N) release were similar to those of eutrophic lakes. Water column nutrient concentrations were high, and FFP tissue was nutrient rich suggesting that the eutrophic condition of the UMR often facilitated abundant FFP. However, tissue nutrient concentrations, and the associations between FFP biomass and water column nutrient concentrations, suggested that nutrients constrained FFP abundance at some sites. FFP abundance was positively associated with SAV abundance and negatively associated with dissolved oxygen concentration. These results illustrate important connections among hydraulic connectivity, nutrient cycling, FFP, SAV, and DO in the backwaters of a large, floodplain river.

Geospatial Extents

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Nutrient cycling, connectivity, and free-floating plant abundance in backwater lakes of the Upper Mississippi River
Series title:
River Systems
DOI:
10.1127/1868-5749/2013/0080
Volume
21
Issue:
1
Year Published:
2013
Language:
English
Publisher:
Schweizerbart and Borntraeger science publishers
Description:
19 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
River Systems
First page:
71
Last page:
89
Number of Pages:
19
Country:
United States
Other Geospatial:
Upper Mississippi River