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Succession in Reefs

Succession in Reefs. 4 stages : Pioneering or Stabilization a. Accumulation of skeletal debris b. Creation of a surface with some relief. Succession in Reefs. 2. Colonization a. Branching & encrusting organisms b. Low diversity. Succession in Reefs. Diversification

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Succession in Reefs

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  1. Succession in Reefs • 4 stages : • Pioneering or Stabilization a. Accumulation of skeletal debris b. Creation of a surface with some relief

  2. Succession in Reefs 2. Colonization a. Branching & encrusting organisms b. Low diversity

  3. Succession in Reefs • Diversification a. Increased diversity of organisms b. Takes the form of a massive structure

  4. Succession in Reefs • Domination a. “lamellar framestones” b. Evidence of high water energy (rudstones) c. Species diversity is reduced

  5. Reef Evolution www.netrocks.net inyo.topcities.com Stromatolites 12 bybp

  6. Reef Evolution Back to “pond slime” Loss of “ecospace” What happens with a sea-level fall? 12 bybp

  7. The Ordovician www.ammonite.free-online.co.uk

  8. Mammelon Astrorhizae Stromatoporoids

  9. Ordovician Reefs (505-438 my) Bryozoan Stromatoporoid Peter Sholle Pratt & James (1982)

  10. Early Silurian Extinction

  11. REEF DIVERSIFICATION Sea-level is back up

  12. The Silurian World 20° OCEAN Equator 20° Chris Scotese

  13. Silurian Time430 mybp Equator Reefs Scotese (1997) Dott & Prothro (1994)

  14. New Life in the Silurian Corals Through Time 0 Wider = more abundant 200 400 600

  15. Crinoids Karla Parsons-Hubbard (Oberlin College) Beloit College Collection

  16. 40 million years later.. Opening up; Sea-level rise Shallow, clear water

  17. Devonian 12 bybp

  18. Late Devonian Why??

  19. Reefs made of sponges….. The Capitan Reef Complex Sea Level Back Up Sea-Level Drops Just when things were looking good….. Devonian

  20. Photo by Peter Sholle Photo by Peter Sholle Photo by Mark Eberle

  21. Extinction Why? • Sea level - no • Climate change - maybe • Ocean chemistry? Reefs disappear!!!!!!!!

  22. A watershed event in reef history?? Zooxanthellae 20 million yr gap

  23. Watch here… Chris Scotese

  24. The cup shaped form is back….. • but it’s a mollusk this time??? A broadening tropics An open pan-equatorial seaway

  25. Open tropical seaway No glaciers !

  26. High temperatures “Greenhouse” climate much warmer than today Too warm for corals Why mollusks and not corals???

  27. Cretaceous Reef Line Reefs Today

  28. Rudist Reefs They photosynthesized?? the missing article…… Photo by D. Schumann (from Woods, 1999) Drawing by John Sibbick (in Woods, 1999)

  29. Dewey McLean Extinction The End of the Cretaceous Images by Mary Parrish, NMNH Irridium Cretaceous Time

  30. Major extinction 95% of species disappear

  31. Reefs have stayed pretty much the same ever since Rest of the Cenozoic

  32. Cambrian “Explosion” Mostly non-reef forms

  33. Increased Calcification Jaws -->BioE Calcification

  34. “Party Crashers” Faster Growth Environment Sea Level More Complex Increased grazing No O2 Wilson Ramirez

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