1. Light, Secchi, Weather and Miscellaneous Comments Liz Ely, Ira Smith, and Margaret Soulman

8. r 2 =0.88 r 2 =0.999

9. (light extinction coefficients fixed now)

11. YSI Group Chris Hotaling Nicole Hotaling Rosa

12. YSI data Five parameters: –Depth, temp., pH, conductivity, dissolved oxygen Measured on multiprobe Graphed actual data (adjusted depth)

13. YSI Parameters Depth –Basin morphometry: nutrients, chemistry, heat balance, productivity, habitat Temperature –stratification, organism distribution pH – measure of H + concentration –chemical forms, organism response

14. YSI Parameters Conductivity – measure of ability to carry an electric current –Indicates ionic content, basin geology Dissolved Oxygen –Respiration, chemical form

21. Whole Lake Adirondack lakes – shallow, lower pH (but not acidic), low conductivity, moderate DO Green, Skaneateles – deep, pH/cond reflects watershed geology Onondaga, Oneida – productive, pH/cond reflect different geology

22. What else? Could measure: –Specific conductance, salinity, redox potential, recent weather patterns Error? –Zero depth, Onon/Oneida depths

23. Nutrients Sampling techniques: strata depths were determined from temperature profile water samples were obtained using Kimmerer bottle three 1 L bottles were filled (1 each from epi, meta, hypo) Analysis: phosphorus, nitrogen, silica dissolved nutrients is target, but acid-digestion in P and Si analyses may release nutrients from particles if sample is not filtered, leading to over-estimate of dissolved concentration

24. Phosphorous The key controlling nutrient in freshwater systems Adding Phosphorous to a system increasing its productivity Deeper lakes will dilute Phosphorous In the presence of oxygen Fe 3+ binds with and ‘traps’ phosphate If the hypolimnion is anoxic phosphorous will be released Rooted aquatic macrophytes take phosphorous up from sediments and releases it into water

25. Sources of Phosphorous Precipitation (dust in the air) Groundwater (small) adsorbs to soil particulates Surface runoff Weathering of calcium phosphate minerals (e.g.. Apatite) - slow process Anthropogenic Sources Point Source – sewage, industry, faulty septic systems, urban runoff Non-point Source – agriculture, animal waste

26. Phosphorous >100Hypereutrophic 30-100Eutrophic 10-30Mesotrophic 5-10Oligotrophic <5Ultra-Oligotrophic Total Phosphorous (  g/L) Lake Productivity Eutrophication – increased growth of biota of lakes and the rate of productivity is higher than would have occurred without any disturbances.

27. Phosphorous – Total Phosphorous

29. Phosphorous – Total Dissolved Phosphorous

31. Phosphorous Conclusions Onondaga Lake considered hypereutrophic and had a much higher phosphorous content than the other lakes contributing to noxious algal blooms Oneida has been eutrophic for over 350 years and is the next highest phosphorous values next to Onondaga Lake although there is a very large gap Wolf Lake is oligotrophic with plenty of oxygen throughout, this allows the phosphorous to be trapped by Fe 3+ in the hypolimnion

32. Phosphorous Conclusions Arbutus Lake near oligotrophic, and followed expected pattern for P Deer Lake - P values seem to do the opposite of expected - possibly due to errors in sampling, such as brushing bottom sediments during sampling Green Lake is very oligotrophic, although the phosphorous concentrations follow those of a lake with anoxic bottom waters due to it being meromictic. Nutrients are entrained in bottom layers, so little in upper layers.

33. Lake Comparisons: Chemistry Nitrogen

34. Sources of Nitrogen in the Water Inorganic nitrogen –Nitrate –Ammonia Organic nitrogen –Organisms –Dissolved Organic

35. General Nitrogen Distribution Within Water Column Surface waters –Increased organic nitrogen Buildup of phytoplankton –Decrease inorganic nitrogen Assimilated by phytoplankton Bottom waters –Increased organic and inorganic Lack of phytoplankton to assimilate inorganic Settling of organic material However, denitrification can convert inorganic to N gas

40. Nitrogen Conclusions Lakes show different nitrogen distributions –Cyanobacteria: present or absent? Nitrogen fixers –Elevate organic nitrogen levels »Epilimnion or metalimnion (stratification effects) –Turnover Nitrogen levels tend toward uniform –Denitrification in bottom waters Due to low oxygen in bottom waters (Eutrophic?)

41. Silica in the Water Column Dissolved: - silicic acids Particulate: - diatoms - organic complexes - adhered to inorganic particles

42. Silica in the Water Column Major source: - degraded alumino-silicate minerals Solubility: - increased by humic compounds Typical Profile: - biogenic reduction of dissolved silica in the epilimnion during early summer, and low epilimnetic silica maintained throughout summer Cause: - intensive assimilation of silica by diatoms, and a greater rate of diatom sedimentation than rate of silica replenishment from sources

43. Expected silica profile (Wetzel)E

44. DISSOLVED SILICA: Sep-Oct, 2003

45. Annual Cycle: Lake in Denmark (Wetzel)

46. Why Opposite of Expected Silica Trends? Possible explanations? - diatom bloom in epilimnion after turnover? - samples were not sufficiently filtered, so [Si] reflects acid-dissolved diatoms as well as dissolved silica? - runoff after rains from soils high in siliceaous materials - or, data were recorded in reverse order