Green Lake (New York)

Infobox_lake
lake_name = Green Lake
image_lake = GreenLakesDeadmanPoint.jpg
caption_lake = Deadman's Point; a "marl reef" is visible in the water.
image_bathymetry =
caption_bathymetry =
location = Onondaga County, New York
coords = coord|43.05|-75.966|type:waterbody_region:US-NY|display=inline,title
type = meromictic
inflow =
outflow =
catchment =
basin_countries = United States
length = 1,141 m
width = 250 m
area = 0.258 km²
depth = 52 m
max-depth =
volume = convert|7235900|m3|acre.ft|abbr=on|lk=on
residence_time =
shore = 2,840 m
elevation =
islands =
cities =

Green Lake is the larger of the two lakes in Green Lakes State Park just east of Syracuse in Onondaga County, New York; Round Lake is the smaller lake located west of Green Lake. Both are meromictic lakes, which means that there is no seasonal mixing of surface and bottom waters. Meromictic lakes have been extensively studied, in part because their sediments can preserve an historical record extending back thousands of years, and because of the euxinic (anoxic, sulfidic) conditions which can form in the deep water.

History

Fayetteville Green Lake (FGL) was the first lake in North America identified as meromictic,] "Transactions of the American Microscopical Society," Vol. 75, No. 3. (Jul., 1956), pp. 334-378.] and is the best studied meromictic lake in the world with records dating back to 1839. Thompson, J. B., Ferris, F. G., Smith, D. A. (1990). "Geomicrobiology and Sedimentology of the Mixolimnion and Chemocline in Fayetteville Green Lake, New York," "Palios" 5, 52-75.] Green Lake was referred to as Lake Sodom by Vanuxem, who was the first to study Green Lake in 1839, and the presence of sulfide in the deeper waters of the lake was known by 1849. FGL is believed to have formed as a plunge pool during the late Wisconsin stage of glaciation at the base of a waterfall formed by the retreating glaciers, which is the reason for its extreme depth relative to a small surface area. The outflow for FGL runs underneath the Erie Canal, which is located within 300m of the north shore of the lake.Brunskill, G. J. and Ludlam, S. D. (1969). "Fayetteville Green Lake, New York. I. Physical and Chemical Limnology," "Limnology and Oceanography" 14(6), 817-829.] FGL is currently located in Green Lakes State Park, and since 1933 large quantities of sand have been dumped on the shore of the north end to create a swimming area.

Biogeochemistry

Fayetteville Green Lake (FGL) is located in the Oswego River-Lake Ontario drainage system; and receives surface water from Round Lake. The water column is chemically stratified into an oxygenated upper portion (mixolimnion) and a euxinic deeper portion (monimolimnion). The stratification is maintained through the large input of ground water rich in dissolved solids to the deeper portion of the lake. Suits, N.S. and Wilkin, R.T. (1998). "Pyrite Formation in the Water Column and Sediments of a Meromictic Lake," "Geology" 26(2), 1099-1102.] The difference in the dissolved solids (Ca, Mg, SO⁴) between the water input to the surface and water input to the deep creates the permanent stratification observed. FGL has a sulfate concentration around 13.5 mmol/L (about half that of modern seawater) which is derived from groundwater input to the deep portion of the lake. A well developed chemocline (a separation in a body of water due to differing chemistries) is present between 18-20 meters depth. The water below the chemocline is anoxic and sulfidic, and at the chemocline there is a dense layer of purple sulfur bacteria which makes the water appear pink. The purple sulfur bacteria thrive in the anoxic waters and utilize the sulfide from the deeper water in their photosynthesis. The color of the lake is created by the large amount of total dissolved solids (from the groundwater input) which disperse the sunlight creating a greenish color. Annual whiting events occur in FGL, due to the large "Synechococcus" population in the lake. Thompson, J. B., Schultze-Lam, S., Beveridge, T. J., Des Marais, D. J. (1997). "Whiting events: Biogenic origin due to the photosynthetic activity of cyanobacterial picoplankton," "Limnology and Oceanography" 42(1), 133-141.] Calcite precipitates in microenvironments surrounding the "Synechococcus" and this is believed to dominate the whiting events. Calcite precipitation is common year round at FGL, and this leads to the carbonate crust that surrounds most of the lake, and covers branches and other material that falls below the surface. Dead Man's Point is a notable example of this, and is classified as a thrombolitic bioherm.

Geologic Significance

The meromictic character of FGL is believed to represent a possible analog to ancient ocean environments during the Precambrian and during times of environmental stress. (i.e. mass extinction events). During these times it has been suggested that the oceans became anoxic and possibly sulfidic in the deep water. Canfield, D. E. (1998). "A New Model for Proterozoic Ocean Chemistry," "Nature" 396, 450-453.] Riccardi, A. L., Arthur, M. A., and Kump, L. R. (2006) "Sulfur isotopic evidence for chemocline upward excursions during the end-Permian mass extinction," "Geochimica et Cosmochimica Acta" 70 (23 - A Special Issue Dedicated to Robert A. Berner), 5740-5752.] Information about past environments can be gained through studying isotopic, chemical, and biological compositions of modern day FGL. FGL is the subject of multiple scientific studies per year. Recent work by Lee Kump at Penn State University has been featured on the television shows "Nova: scienceNOW" [http://www.pbs.org/wgbh/nova/sciencenow/3318/01.html "Mass Extinction"] , episode of the television program "NOVA scienceNOW" broadcast November, 2006.] and National Geographic,Naked Science: Dino Meteor] relating FGL to the end-Permian mass extinction.

References

External links

* [http://www.youtube.com/watch?v=Tt8k0WbAnFs "The Underwater World of Green Lakes"] , video obtained using a robotic submarine by Dr. Mark A. Teece
*gnis|951701|Green Lake