CASE HISTORIES


A. Changes in the Adirondack Lakes
        •80% of lakes have acidified since pre-industrial times
        •Began acidifying between 1900 and 1950
        •Even naturally acidic lakes acidified further
        •30-40% of lakes have eutrophied
        •Strong increase in salinity in 30% of the lakes

B. Changes in Daphnia performance pre- and post-eutrophication in European lake; potential for 'resurrection ecology'

C. Onondaga Lake
        •Described as the most polluted lake in the United States
        •Rapidly flushed (3.9 flushes/year)
        •Large inputs of domestic and industrial wastes
        •Salt springs on east side of the lake – manufacturing began in 1794, peaked in 1862, persisted until 1920 – bulk of US salt supply around 1800
        •1822 cut a channel to permit lake’s surface elevation to drop to that of the Seneca River (Erie and Barge canal system)
        •Soda ash production (Solvay Process) in 1884; later Allied Chemical Co. and then Allied Signal
        •Successful salmonid fishery in 1870’s and 1880’s; resorts on the shoreline.  Fishery and resorts gone by 1890’s.
        •Swimming banned in 1920
        •1951 began trying to reduce discharge of mercury to the lake from the soda ash facility; fishing banned due to mercury contamination
                (angling allowed again in 1986, but fish are not to be eaten).
        •1994 – sediments, tributaries and some shoreline designated a superfund site
        •Not only soda ash (Na2CO3), but also 30 other chemicals were produced at the plant from 1884-1986.
        •Until 1900 waste was discharged directly into the lake; then it was put into waste beds
        •About 30% of the lake shore is wastebeds (2,000 acres; 8.1 km2), some 21 m high – not lined
        •Mercury from chlor-alkali process dumped into the lake from 1946-1986 – 10 kg/d
        •Benzene production – hydrocarbons of benzene origin in the sediments
        •First scientific studies in 1960’s
        •Upstate Freshwater Institute: www.ourlake.org, www.upstatefreshwater.org
        •Paleolimnological studies to look at changes in the lake – debates over historical changes in nutrients, pollution, salinity…

        Daphnia exilis      'resurrection ecology'
        •Range expansion of 1,000 km
        •Present in Onondaga Lake from mid-1920’s and mid-1980’s
        •Only most recent eggs still hatch (mercury?)
        •May have done well in the lake due to higher salinity and low fish abundance; declined as fish returned
        •Genetic analysis suggests that population may have started from one or a few individuals (hypothesize that were transported
            on boots or equipment from a plant in Missouri)

       Current conditions and debate over lake remediation plans

   

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