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  • Soils that contain phosphorus are tilled under each year and retain the element for many years, even decades. This sediment also finds it way to the bottom of waterways where it gets recycled into the water when it warms each year. This is one reason I think it is a lengthy reduction problem.
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  • 1. GROWING PAINS Uneasy co-existence: Lake Champlain and the modern humans R.Lana Spahr
  • 2. Lake Champlain, briefly designated as one of America's "Great Lakes" is certainly one of the largest and most extensive freshwater lakes in the country. It spans geo- political boundries, as well as ecosystems and watersheds, 120 miles wide, up to 12 miles wide and containing an immense 6.8 quadrillion gallons of water.
  • 3. Objective of Presentation I intend to demonstrate how the Lake Champlain environment is negatively affected by human-created nutrient over-load, or eutrophication and why applied solutions have had only an incremental effect. The Lake's regions,or segments, some naturally eutrophic, have collectively become more so, with one result manifestation as algal blooms and damaged ecology resulting from this. While Phosphates are the general cause of this phenomenon, it is not simply an obvious cause and effect situation. The factors involved include increased population and population density, greater reliance on intensive agriculture, and a collective (over time) result of many human activities. Combine eutrophication with the impact of exotic species and you have a situation of over-all weakened ecosystems.
  • 4. Ecological Mechanisms While Nitrogen adds to the process of Eutrophication, it is considered a lesser limiting factor in freshwater bodies while Phosphorus is the primary limiting factor in the growth of primary producers such as algae. The Lake has several basin regions, which are of varying depth, geologic characteristics, fed by differing watersheds and sometimes separated by shallow bars. Theses differing basins and bays have differing trophic levels, varying from a clear oligotrophic environment, with low natural algae growth and nutrients and high oxygen levels to a turbid eutrophic environment, high nutrient levels and algae growth and low oxygen levels.The naturally eutrophic segments of Lake Champlain are usually bordered by extensive wetlands, for example the South Lake, where decaying plants and feeding m organisms cycle Phosphorus back into its shallow depths.
  • 5. Ecological Mechanisms (Con't) Eutrophication is a hazard because algae quickly increases its population, and oxygen is suddenly scarce, and light diminished. Algae increases the plankton, which temporarily increases food for snails and fish. As these populations briefly swell, this is unsustainable, and they soon die-off. The micro- organisms involved in the decomposition use still more Oxygen, and the balance is altered further. In addition, some fish need a certain turgidity and sediment of water to lay their eggs in and when the ecology is shifted, exotic species who are adapted to this new less-oxygenated, lower light environment might gain a foot hold.
  • 6. Before analyzing the phosphorus run-off in the Lake, lets look at the watersheds surrounding the Lake.
  • 7. WATERSHED PHOSPHORUS Phosphorous enters into lakes and rivers in many ways - storm drains, as a by-product of waste-water treatment and through various industries. These are 'point-sources' where you can 'pin-point' the source. A large amount of it however, almost 80%, doesnt enter directly, but is agricultural run-off from manure and fertilizers and development run-off (i.e. lawn fertilizers, detergents that first filter thought watersheds. These are non-point sources, diffuse and widespread. The horizontal lines on the previous graphic show the measured phosphorus and the target (ideal) phosphorus for each section of the Lake.
  • 8. Intensive Agriculture and Phosphates 1. Phosphorus on regional farms was often federally subsidized, and it was enormously cheap use. Many previously forested land was converted to farm to intensive corn and dairy farming. In Franklin County, NY heavily fertilized corn planting rose from 7.000 in 1950 to 27,000 acres in 2002. Franklin county contains the St' Lawrence watershed which drains into the Lake. (source: R. Holt- love live share website) Not only does this add to the overall Phosphorus load, the loss of the forests in the watershed means less filtration. 2. In addition to the fertilized hay, alfalfa, and corn grown often for Dairy cattle often requires phosphorus. A dairy cow's urine and manure contains 30 times a human's production of Phosphorus. Phosphorus run-off can be reduced by applying manure when the ground isn't frozen, composting correctly, and adjusting animal's feed to give them only the amount of Phosphorus that they need. Riparian buffer zones can help to filter hosphorus, before a stream or creek. and uptake the P
  • 9. Changes in population & Land Use As 80% of lake Champlain's Phosphorus run-off is from non- point sources, it is important to look at the surrounding area. The lake Champlain Basin program (LCBP) has fouund an increase in area population of 25% from 1970, and 6.1% from 1990. While these might not be huge numbers, consider the map in the previous slide- certain areas have doubled their population (200% or more). It is interesting - i found that Phosphorus levels didn't correspond with cities and towns. Overall, the trend has been forested land has become farmed, and farmed land is being developed. Consider that 1200 out of 1900 of Vermonts farms are in the Lake Champlain watershed! (Source: vermontagriculture.com)
  • 10. Analysis of Phosphorus Levels Although the previous graphic seperated oligotrophic, eutrophic, and mesotrophic (intermediate) basins of the Lake, the overall trend was eutrophication. TMDL is the Total Maximum Daily Load of Phosphorus that a waterway can process, and the TMDL , differing for various regions and ecosystems within the lake is marked by a red line. Most sections of the Lake were close to that line or vastly exceeding it.
  • 11. Comparison of Land use and Phosphorus I have found that the segments of th e Lake found in 2000 to be impaired by the VA-NR DEC (Vermont Agency of natural Reasources, Dept. of Conservation are the same areas that experienced population growth, watershed contamination, and high Phosphorus levels. For example, the watershed feeding the Otter Creek segment had an area population growth of 50- 200% in different parts of it. This segment of the Lake measured very high in Phosphorus in the 90s, as did its watershed. Population growth by itself doesn't always indicate a large increase in Watershed and Lake levels, as an increase in people isn't an indicator for type of land use. However the correlation of watershed and lake Phosphorus excess was much closer.
  • 12. Comparison of Land use and Phosphorus (con't) The six highest concentrations of watershed Phosphorus, including the highest level of Missisquoi Bay, whose watershed spans New york, vermont, and Canada, were all areas of the Lake Champlain waters that the Vermont Department of Conservation flagged as 'impaired waterways'. Although population growth paid a large part into the Phosphorus problem, the impairment and hazardous TMDLs of the Watersheds was the greatest cause of the Phosphorous problem.
  • 13. Persistence and Continued Efforts While there are dozen of non-government and government organizations that are working to improve Lake Champlain for all of its human and non-human inhabitants, efforts to fight Eutrophication have been mixed. Phosphorus, to some degree stays put- it does not combine to form a gas like Nitrogen or Sulfur. On a farm, for example, the soil chemistry and ecology can suffer from Eutrophication. the Phosphorus in the soil will leach out eventually, sometimes for decades and this has been found to be the case in the lake Champlain area (citation found but lost). This makes improvements in agriculture and newer BMPs (Best Management practices), hard to measure. Of course, non-point sources are hard to regulate, as they occurs over hundreds of acres, and across jurisdictions. In conclusion, knowing exactly how to measure the progress is as important as education and mitigation of the problem.