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

Nutrient loading to Onondaga 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.

“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 (Matthews et al. 2001;Effler et al. 2002bEffler et al. , 2005)).”

Reductions in primary production of similar magnitude (between 32 and 39%) were reported from before (1978) to after closure (2002) of the facility, supporting its coupling to POCdf.

“Reductions in primary production of similar magnitude (between 32 and 39%) were reported from before (1978) to after closure (2002) of the facility (Effler et al. 2005), supporting its coupling to POC df .”

A decrease in the peak DO demand of 37% occurred from the 1989-1991 to the 2002-2004 interval, generally consistent with the observed decreases in primary production and POCdf.

“A decrease in the peak DO demand of 37% occurred from the 1989-1991 to the 2002-2004 interval, generally consistent with the observed decreases in primary production (Effler et al. 2005) and POCdf.”

Summer average epilimnetic concentrations of total phosphorus (TPe) have generally decreased in response to reductions in Metro's effluent concentrations.

“The summer average epilimnetic concentrations of TP (TP e ) have generally decreased (Fig. 7b) in response to reductions in Metro's effluent concentrations (Effler et al. 2005).”

The closure of the soda ash industry in Onondaga Lake in 1986 resulted in an abrupt decrease in organic carbon deposition, which was likely associated with a similar decrease in primary production.

“The closure of an industry in 1986 resulted in an abrupt decrease in organic carbon deposition that was likely associated with a similar decrease in primary production (Effler et al. 2001(Effler et al. , 2005)).”

Onondaga Lake was described as nearly nutrient saturated through the early 1990s.

“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).”