1 / 32

Contents

Contents. Ecosystem Recovery Calcium Experiment Introduction to Soils Calcium Experiment Results.

blaine
Download Presentation

Contents

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Contents • Ecosystem Recovery • Calcium Experiment • Introduction to Soils • Calcium Experiment Results

  2. The Clean Air Act and Amendments have decreased emissions of sulfur dioxidein airwhich has increased the pH of precipitation in the Northeast……but ecosystems are responding more slowly. Both pH and the ability to buffer acidity in soil, lakes and streams remain low in acid sensitive areas. I. Ecosystem Recovery Hubbard Brook Acid Rain Story: Part II

  3. Why is there a delay in ecosystem recovery? I. Ecosystem Recovery • Acid rain continues to fall in the Northeast • The effects of acid rain on acid-sensitive soils, and thus ecosystems, is complex and long-lasting. There are several reasons…

  4. Acid rain still falls in the Northeast: I. Ecosystem Recovery 1.The Clean Air Act(s) reduced sulfur dioxide, but another emission, nitrogen oxide, has not been substantially reduced and still contributes to acid rain. 2. Sulfur dioxide has been reduced, but not eliminated (see following graph).

  5. I. Ecosystem Recovery Data provided by G.E. Likens through funding from the National Science Foundation and the A.W. Mellon Foundation.

  6. I. Ecosystem Recovery Why is ecosystem recovery delayed? 1. Acid rain causes increased loss of base cations from soil this causes Lower fertility of soils (base cations are nutrients necessary for tree growth). Decrease in acid neutralizing capacity (ANC) of soils (reduced ability to buffer the incoming acids)

  7. I. Ecosystem Recovery Why is ecosystem recovery delayed? 2. Acid rain has increased dissolved inorganic aluminum in soil waters. At high concentrations, this form of aluminum is toxic to plants and animals. Hubbard Brook Acid Rain Story: Part II

  8. II. Calcium Experiment To further investigate the effects of acid rain on an ecosystem, HBES scientists developed a hypothesis: If calcium is replaced across a whole forested watershed, recovery from acidification will accelerate. This response will allow us to better understand the role acid rain plays as a forest stressor Hubbard Brook Acid Rain Story: Part II

  9. II. Calcium Experiment HBES scientists received a 5-year grant from the National Science Foundation in 1999 to conduct an experiment to replace the calcium lost from one entire, 29-acre watershed (Watershed 1), and monitor the forest response.

  10. Chemical and biological characteristics of Watershed 1 (calcium-treated watershed)compared with the same characteristics ofWatershed 6 (“reference” watershed that is not treated in any way) II. Calcium Experiment They monitored: A “reference” in ecosystem science is similar to a “control” in an experiment.

  11. Chemical: Soil and stream pH Soil and streamwater chemistry Biological: Nutrient content of plant foliage Tree seedling regeneration Canopy tree health Soil arthropod density and diversity Snail densities Some of the characteristics they monitored included: II. Calcium Experiment

  12. Wollastonite, a calcium-rich mineral, was pulverized… II. Calcium Experiment Photos courtesy of T. Siccama

  13. …and made into pellets. II. Calcium Experiment

  14. The wollastonite pellets were were loaded into sacks. II. Calcium Experiment

  15. A backhoe then put a sack into a hopper II. Calcium Experiment

  16. II. Calcium Experiment Then a helicopter picked up the hopper and spread the pellets evenly across Watershed 1.

  17. Can you spot the pellets on the forest floor? II. Calcium Experiment

  18. After eight years, some pellets are still there, under layers of organic matter. II. Calcium Experiment wollastonite pellets Photo courtesy of T. Siccama

  19. These remaining pellets represent a “bank” of calcium in Watershed 1. II. Calcium Experiment They continue to contribute to the acid neutralizing capacity of the soil and stream water.

  20. III. Introduction to Soils • Soils have layers. • You can see these layers if you dig a pit to expose a soil profile. • Each layer has a different composition, which can be seen in terms of color, texture, chemistry, etc. • The next slide shows layers of a soil profile. Hubbard Brook Acid Rain Story: Part II

  21. III. Introduction to Soils O A E Bhs Bs BC Cd Photo courtesy of S. Bailey

  22. Here are some soil pHand stream pH results for Watershed 6(reference)andWatershed 1(calcium treated) IV. Calcium Experiment Results Hubbard Brook Acid Rain Story: Part II

  23. General pH today in the Reference Watershed (W 6: no treatment) Precipitation pH  4.4 Stream Soil Soil pH: O  3.5 Bh  4.0 Bs  4.5 C  5.0 Stream pH at Weir  5.1 Bedrock Hubbard Brook Acid Rain Story: Part II

  24. General pH today in the Treated Watershed (W 1: calcium added) Precipitation Mean pH in treated watershed (WS 1) pH  4.4 Stream Soil Soil pH: O  4.5 Bh  4.0 Bs  4.5 C  5.0 Stream pH at Weir  5.4 Bedrock Hubbard Brook Acid Rain Story: Part II

  25. pH Comparison of W 6 and W 1 * The pH scale is logarithmic; every increase of 1 on the pH scale means that acidity decreases by a factor of 10.

  26. Watershed 1 is showing signs of chemical recovery: IV. Calcium Experiment Results • higher pH of stream water • more soil base cations as compared to Watershed 6, the reference (no treatment) watershed.

  27. Watershed 1 is showing signs of biological recovery: IV. Calcium Experiment Results • better growth of sugar maples • sugar maple seedlings show higher densities and survival • as compared to Watershed 6, the reference (no treatment) watershed.

  28. To find out how ecosystem recovery happens, see… The Hubbard Brook Acid Rain Story Part III: Ecosystem Recovery

  29. Acid Rain Revisited a Science Links publication by the Hubbard Brook Research Foundation http://www.hubbardbrookfoundation.org For more detailed information on ecosystem recovery:

More Related