Changes in Deposition of Phytoplankton Constituents in a Ca²⁺Polluted Lake

Abstract

Systematic reductions in the deposition rate of organic C, N, P, and chlorophyll (Chl) are documented for Ca2+ polluted, culturally eutrophic, Onondaga Lake, NY, based on analyses of weekly sediment trap collections over the May-October interval for 10 years of the 1980-1992 period. Inputs of both nutrient-rich domestic waste and industrial salt waste (including Ca2+) decreased over this period. Constituent ratios of the collected sediment indicate phytoplankton biomass was the dominant source of the deposited organic C, N, and Chl. Substantial decreases in downward fluxes of these constituents occurred starting in 1987: 37, 42, 25, and 54%, on average, for organic C, N, P, and Chl, respectively. These reductions were driven primarily by the decreases in the lake's salinity and Ca2+ concentration, that resulted from the closure of a soda ash manufacturing facility (1986), rather than decreases in water column P concentrations from reductions in domestic waste loading. Three different mechanisms for the decreased deposition, related to the reductions in salinity and Ca2+ concentration, are considered: (i) decrease in coating of phytoplankton with CaCO3 precipitate, (ii) increased grazing of phytoplankton by large cladocerans, and (iii) decreases in coagulation of phytoplankton. The greater loss of phytoplankton biomass through deposition, driven by salt waste inputs from the industry, exacerbated the lake's problem of high primary production. This response is consistent with ecological theory for nutrient saturated phytoplankton growth but has not previously been demonstrated on a whole-lake basis.

Inorganic tripton in the Finger Lakes of New York: importance to optical characteristics

“…Inorganic tripton (i.e., non-living or non-biogenic inorganic particles; Wetzel, 2001) can have important implications for the ecology and water quality of aquatic systems by affecting metabolic activity (Hart, 1988;Phlips et al, 1995), presenting reactive surfaces that function in the cycling of critical constituents (Sondergaard et al, 1992;James et al, 1997;Simpson, 1998), influencing the concentration and stoichiometry of particulate constituents (Hecky et al, 1993;Effler et al, 2001a), and attenuating light (Kirk, 1985;Weidemann et al, 1985;Effler et al, 2000Effler et al, , 2002b. Sources of inorganic tripton include autochthonous production of oversaturated mineral phases (Kelts & Hsu¨, 1978;Yin & Johnson, 1984;Hodell et al, 1998), allochthonous inputs (Kirk, 1985;Peng et al, 2004), and resuspended sediment (Bloesch, 1995;James et al, 1997).…”

Implications of redox processes for the rehabilitation of an urban lake, Onondaga Lake, New York

“…(2) high salinity levels eliminated largebodied efficient grazing zooplankton (Daphnia; Hairston et al 2005); (3) high Ca 2+ promoted increased phytoplankton production through enhanced deposition of phytoplankton (Effler et al 2001b); and (4) saline (i.e., dense) waste plunged in the water column and extended the duration of stratification and irregularly caused failure of spring turnover (Owens and Effler 1989). These effects were largely eliminated by the closure of the facility (Effler and Matthews 2003).…”

“…7e; Effler et al 2001b) depicts systematic reductions for the lake (~37%) starting the year after closure of the soda ash industry. Relatively uniform fluxes were observed both before and after the abrupt decrease in S. 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 POC df .…”

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

“…The values of POC df (Fig. 2d) are averages for weekly sediment trap collections (metalimnetic deployments) for the April -October interval of 1980, 1981, and 1985-1992, as reported by Effler et al (2001). Data for Chl e presented (Fig.…”