title: Long-term and seasonal trend decomposition of Maumee River nutrient inputs to western Lake Erie.
abstract: Cyanobacterial blooms in western Lake Erie have recently garnered widespread attention. Current evidence indicates that a major source of the nutrients that fuel these blooms is the Maumee River. We applied a seasonal trend decomposition technique to examine long-term and seasonal changes in Maumee River discharge and nutrient concentrations and loads. Our results indicate similar long-term increases in both regional precipitation and Maumee River discharge (1975-2013), although changes in the seasonal cycles are less pronounced. Total and dissolved phosphorus concentrations declined from the 1970s into the 1990s; since then, total phosphorus concentrations have been relatively stable, while dissolved phosphorus concentrations have increased. However, both total and dissolved phosphorus loads have increased since the 1990s because of the Maumee River discharge increases. Total nitrogen and nitrate concentrations and loads exhibited patterns that were almost the reverse of those of phosphorus, with increases into the 1990s and decreases since then. Seasonal changes in concentrations and loads were also apparent with increases since approximately 1990 in March phosphorus concentrations and loads. These documented changes in phosphorus, nitrogen, and suspended solids likely reflect changing land-use practices. Knowledge of these patterns should facilitate efforts to better manage ongoing eutrophication problems in western Lake Erie.
authors: †Great Lakes Environmental Research Laboratory (GLERL), National Oceanic and Atmospheric Administration (NOAA), 4840 South State Road, Ann Arbor, Michigan 48108, United States.
authors: Craig A
authors: CA
authors: Stow
authors: ‡School of Natural Resources and Environment, University of Michigan, 440 Church Street, Ann Arbor, Michigan 48109, United States.
authors: YoonKyung
authors: Y
authors: Cha
authors: §National Center for Water Quality Research, Heidelberg University, 310 East Market Street, Tiffin, Ohio 44883, United States.
authors: Laura T
authors: LT
authors: Johnson
authors: §National Center for Water Quality Research, Heidelberg University, 310 East Market Street, Tiffin, Ohio 44883, United States.
authors: Remegio
authors: R
authors: Confesor
authors: §National Center for Water Quality Research, Heidelberg University, 310 East Market Street, Tiffin, Ohio 44883, United States.
authors: R Peter
authors: RP
authors: Richards
mesh_terms: D002980:Climate; D004784:Environmental Monitoring / Q000379:methods; D005068:Eutrophication; D006114:Great Lakes Region; D060106:Lakes / Q000032:analysis*; D009566:Nitrates / Q000032:analysis; D009584:Nitrogen / Q000032:analysis*; D010758:Phosphorus / Q000032:analysis*; D045483:Rivers; D012621:Seasons; D014876:Water Pollution / Q000032:analysis
chemical_list: D009566:Nitrates; D010758:Phosphorus; D009584:Nitrogen