FAYETTEVILLE GREEN LAKE, N.Y.
Fayetteville Green Lake (FGL) is one of two lakes in Green Lakes State Park near Fayetteville, N.Y. (east of Syracuse in upstate New York). The lakes occupy steep-sided plunge pools formed as a result of short-lived though massive waterfalls associated with floods released near the end of the last glacial period (~10,000 years ago). The waterfalls dug the holes out of shale units that contain gypsum (calcium sulfate, which is used to make drywall). This gypsum dissolves in groundwater, and this groundwater fills the lakes. Due to this, FGL has sulfate concentrations that reach ~15 mM, which is close to half that of seawater (~28 mM). Another interesting feature of FGL is that it is meromictic, meaning it does not fully mix. As a result, the deep water has become euxinic (sulfide rich and devoid of oxygen) from the action of sulfate reducing bacteria, which break down organic matter, and in the process reduce sulfate to hydrogen sulfide. The levels of hydrogen sulfide in the deep water (below ~20 m) reach toxic levels for humans, making diving a dangerous endeavor. The hydrogen sulfide is not toxic to all life, however, and it is actually an energy source for purple sulfur bacteria, which live at ~21 m, and are so thick, that when water is brought up from that depth, it is pink! Purple sulfur bacteria use anoxygenic photosynthesis to harness light energy to make organic molecules, only instead of producing oxygen (like land plants), they convert hydrogen sulfide to elemental sulfur and sulfate. The upper water is oxygenated, and supersaturated with oxygen due to cyanobacteria carrying out oxygenic photosynthesis. All of these factors contribute to FGL having a transition from 15 to 21 meters where the water column goes from oxic to anoxic, resulting in dramatic changes in the concentration of manganese, iron, and molybdenum. FGL may serve as a proxy for the kinds of conditions that existed in the earth's oceans around 2 billion years ago. We have been studying FGL since the summer of 2012, collaborating with Michael McCormick at Hamilton College in Clinton, NY and Lee Kump at Penn State.
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A lovely July morning on Fayetteville Green Lake, N.Y. The beauty overlies deep water that is rich in deadly hydrogen sulfide. Fortunately, the hydrogen sulfide is only found below 20 m, thanks in part to the efforts of anoxygenic phototrophs. Photo by Jeff Havig.
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Dead Man's Point, Fayetteville Green Lake, N.Y. This is a partially exposed thrombolite, in this case the calcite deposited is thought to be precipitated as a result of cyanobacterial and algal photosynthesis. Photo by Jeff Havig.
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Deploying the 'McCormick Sampling Device' from the Hamilton College S.S. Continental Drifter. Dr. Michael McCormick's ingenious way of collecting instantaneous water samples through the entire 53 m water column at FGL (learn more from McCormick et al., 2014). Photo by Jeff Havig.
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The following are some figures from papers on Fayetteville Green Lake:
Havig et al. (2015) Figure 3: Redox indicators for the water column. The chemocline is clearly delineated at the top (15 m) with a decrease in dissolved oxygen, and on the bottom (21 m) by an increase in total sulfide. |
Havig et al. (2015) Figure 5: Trace element (Mn, Fe, Co, Ni, and Mo) concentration in the water column. Manganese, iron, and cobalt exibit peaks in concentration coincident with the bottom of the chemocline. Molybdenum concentration decreases from the oxic mixolimnion to the euxinic monimolimnion. Nickel remains a mystery, showing no change across the chemocline. |
Havig et al. (2015) Figure 6: Manganese concentration plotted with dissolved oxygen, nitrate, ammonium, and total sulfide for 15 to 25 m depths. The peak in Mn concentration is coincident with a decrease in nitrate and ammonium, and is within the high turbidity area demarcating a zone of purple sulfur bacteria. |
Havig et al. (2015) Figure 11: A conceptual model for the movement and cycling of trace elements in FGL. |
Havig et al. (2017) Figure 7: Scanning electron microscope images of thin sections made from sediments collected from the top 5 cm (0 to 5 cm depth, left) and from the bottom 8 cm (40 to 48 cm depth, right) of a core collected from FGL in July, 2015. Diatom frustules (SiO2) show up as dark grey, carbonate crystals as light grey, and iron sulfide minerals as white. Field of view is identical for both images (note scale). |
Havig et al. (2017) Figure 10: Conceptual model for carbon cycling and resulting stable isotope signals at Fayetteville Green Lake. All water δ13C values represent average values for the representative water layers. Corg = organic carbon, DIC = dissolved inorganic carbon, PSB = purple sulfur bacteria, GSB = green sulfur bacteria, SROs = sulfate reducing organisms. Sediment values represent surface (0 to 5 cm depth range). Plant matter values are from leaf biomass analyses in Fulton (2010). Water column Corg values calculated using data from this study and Fulton (2010). |
Below are three manuscripts that we have published with our colleagues from work done at Fayetteville Green Lake:
| 2015_havig_et_al_trace_element_behavior_at_meromictic_fgl.pdf |
| 2017_havig_et_al_carbon_stable_isotopes_at_fgl.pdf |
| 2018_herndon_et_al_mn_and_fe_in_seds_of_fgl.pdf |
CYANOBACTERIAL BLOOMS IN LAKES AND RESERVOIRS
Above: Cyanobacterial bloom on a reservoir in June, 2015 (Photo by Jeff Havig)
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Cyanobacterial blooms (colloquially referred to as 'algal blooms') have become an increasing occurrence on reservoirs and lakes across the country, including Ohio. While in many cases the harm is only to the aquatic ecosystem, some cyanobacteria also produce toxins that are harmful to humans and other multicellular life. An example of this is microcystin in Lake Erie. As a result of anthropogenic activities, Lake Erie has experienced eutrophication (increased primary productivity) linked to inputs of nitrogen and phosphorous, resulting in massive blue-green cyanobacteria blooms and zones of anoxia (water devoid of oxygen, in this case due to breakdown of organic carbon produced by cyanobacteria). Compounding this eutrophication problem is the proliferation of the invasive non-native mussel species Dreissena polymorpha (Zebra mussel) and Dreissena bugensis (Quagga mussel) into the Lake Erie system. In recent years, blooms of potentially toxic cyanobacteria (e.g., Microcystis spp., Planktothrix spp.) have persisted in Lake Erie during the summer (August to September), resulting in negative impacts on water quality within the lake associated watersheds. Several species of cyanobacteria, including Microcystis spp. and Planktothrix spp., produce the toxin microcystin (amongst others). During toxic blooms, the levels of microcystin in Lake Erie can exceed the provisional guideline concentration set by the World Health Organization. Over the past decade, cyanobacterial blooms in Lake Erie have grown so large that they are visible from space and levels of microcystin have reached concentrations that are 50 times greater than that recommended by the World Health Organization for safe recreation. As a result of a large bloom in 2014, the microcystin levels reached such toxic levels that the drinking water for the Toledo metropolitan area was deemed unsafe for drinking.
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Above: A picture of me holding my prey: cyanobacterial bloom water sample from Grand Lake St. Mary's in eastern Ohio (Summer, 2015). The sampling device is called a Van Dorn bottle, and it allows for collection of a discrete water sample from a specific depth. We kayak out to a sample location, collect in situ data using a SONDE which can measure pH, temperature, conductivity, dissolved oxygen concentration, and turbidity through the entire water column. Then we collect water samples and sediment samples, and bring them back to shore to process. We successfully employed this technique to collect samples from this site as well as several others, including Buckeye Lake, Crystal Lake, and Lake Erie (where the Maumee River empties into it at Toledo, and in Sandusky Bay). Photo credit: Dr. Trinity Hamilton
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Above: Lake Erie as imaged from space during the summer of 2011, showing the cyanobacterial bloom (green). Detroit, MI is left center, Toledo, OH is lower left, and Cleveland, OH is bottom center left. Lake Erie serves as the primary water source for an estimated 11 million people. Photo courtesy of NASA/Earth Observatory.
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We conducted sampling from Cincinnati, OH north to the Maumee River and on to Lake Erie, and east of Columbus, OH to western Indiana to collect geochemical and microbiological samples. We are using the data we have collected (and will continue to collect at new sites in Minnesota) to work towards a better understanding of what is driving these blooms, and the effects of those blooms on the aquatic ecosystem.
Before you head out to swim, boat, or fish in your local favorite lake or reservoir, you can look to make sure that there hasn't been an advisory. Here is a link to the Ohio Environmental Protection Agency website where advisories are posted (just copy and paste it in your web browser): http://wwwapp.epa.ohio.gov/gis/mapportal/hab.html Ingestion of microcystin can cause nausea, vomiting, diarrhea, and numbness. Pets that swim in water with dangerous levels of the toxin can die. Fish captured in water with the toxin can have dangerous levels of the toxin accumulate in the fatty tissues, making them, in turn, toxic. |
Who are the culprits driving these blooms? We need look no farther than our own noses. Human production of CO2 through burning of fossil fuels is driving global climate change, causing increased temperatures. Cyanobacteria productivity is linked to temperature, so the warmer the water, the greater the activity. However, cyanobacteria also need nutrients to grow, including nitrogen and phosphorous. Humans prove to be an excellent source of these nutrients, as fertilizers used to make lawns green and increase farm yields (there are 13.9 million acres of farmland in Ohio) run off the land and flow into the waterways. Also, input of agricultural runoff from livestock (cattle, chickens, turkeys, pigs, etc.) is a direct source of nitrogen and phosphorous. Ohio has approximately 1.5 million cattle and 2.0 million hogs (www.agclassroom.org/oh), which produce about 25 million tons of manure per year (based on my back-of-the-envelope calculations from manure production values published by the University of Wisconsin Extension Services). Furthermore, sewage produced by humans is flushed directly into Lake Erie. According to a PIRG report, 8 billion gallons of raw (unprocessed) sewage was dumped into Lake Erie in 2004 alone. That is the equivalent of 1.2 million people flushing their toilets directly into the lake every day for an entire year, or nearly the entire population of North America flushing their toilets once into Lake Erie. These cyanobacterial blooms are easy-to-recognize signs of a sick environment.
So there's the bad news. The good news? We are the problem, which means that we can be the solution! More responsible stewardship of our planet will only make things better, and that starts with you. What will you do today to change your behavior and enact positive change for the planet we all live in and our children will inherit?
So there's the bad news. The good news? We are the problem, which means that we can be the solution! More responsible stewardship of our planet will only make things better, and that starts with you. What will you do today to change your behavior and enact positive change for the planet we all live in and our children will inherit?
