Changes in Primary Production in Onondaga Lake, NY: Magnitude, Metrics, and Drivers

Partitioning phosphorus concentrations and loads in tributaries of a recovering urban lake

“…The P load from Metro has been the primary driver of cultural eutrophication in the lake (Effler et al 2005, Effler et al 2008a. Concentrations of TP in this effluent (TP Metro ), and thereby its TP load (TP Metro/L ), have decreased in response to multiple management actions, including a ban on high P content detergents within the service area in 1971 (Murphy 1973) and treatment upgrades, particularly in 1979 (secondary treatment), 1981 (tertiary treatment) and 2005 (high rate flocculated settling).…”

Assessment of Long-term Trends in the Oxygen Resources of a Recovering Urban Lake, Onondaga Lake, New York

“…Nutrient loading to the lake has been reduced substantially over the past three decades as a result of the phosphorus detergent ban, industrial pre-treatment and upgrades at Metro Effler et al 2002bEffler et al , 2005. Despite a 30-fold reduction in Metro's P load since the early 1970s (Effler et al 2005), the lake was described as nearly nutrient saturated through the early 1990s (Connors et al 1996). Summer average epilimnetic TP concentrations continue to exceed 50 µg/L in most years (Fig.…”

“…These byproducts are oxidized during the fall mixing period, causing severe depletion of DO (e.g., DO <5 mg/L) in the upper waters (Gelda and Auer 1996). Nutrient loading to the lake has been reduced substantially over the past three decades as a result of the phosphorus detergent ban, industrial pre-treatment and upgrades at Metro Effler et al 2002bEffler et al , 2005. Despite a 30-fold reduction in Metro's P load since the early 1970s (Effler et al 2005), the lake was described as nearly nutrient saturated through the early 1990s (Connors et al 1996).…”

“…The primary cause of these DO problems has been nutrient loading from Metro, which has sustained high rates of primary production in the lake (Effler et al 2005). The soda ash facility compounded the lake's DO problems by altering the stratification regime (Owens and Effler 1989) and increasing primary production through establishment of artificially high settling rates of phytoplankton under nutrient-saturated conditions .…”

“…The occurrence of extreme DO concentrations has been reduced, and DO levels are now more frequently in balance with atmospheric concentrations. The primary cause for this change was the decrease in primary production that occurred following closure of the industry (Effler et al 2005). Chlorophyll a concentration, a surrogate measure of phytoplankton biomass and primary production, has been demonstrated to influence seasonal DO dynamics in this system (Fig.…”