Are Hypercalcified Demosponges A Key To The EndPermian Extinction - PowerPoint PPT Presentation

Title: Are Hypercalcified Demosponges A Key To The EndPermian Extinction


1
Are Hypercalcified Demosponges A Key To The
End-Permian Extinction?

• Robert M. FinksDepartment of Geology
• Union College Schenectady, NY

2
HYPERCALCIFIED DEMOSPONGES ARE ALMOST THE ONLY
SPONGES TO SURVIVE THE END-PERMIAN EXTINCTION
3
(No Transcript)
4
(No Transcript)
5
(No Transcript)
6
(No Transcript)
7
(No Transcript)
8
(No Transcript)
9
(No Transcript)
10
(No Transcript)
11

• THE HIGH SURVIVAL RATE OF HYPERCALCIFIED
  DEMOSPONGES SUPPORTS THE HYPOTHESIS THAT THE
  END-PERMIAN EXTINCTION WAS CAUSED BY
• (1) HYPOXIA
• (2) ATTENDANT DISRUPTION OF FOOD-CHAIN
• (3) ATTENDANT HIGH ULTRAVIOLET FLUX BECAUSE
  OF LOSS OF OZONE LAYER

12

• REASONS
• (1) DEMOSPONGES CAN HAVE SYMBIOTIC CYANOBACTERIA
• (2) HYPERCALCIFIED DEMOSPONGES CAN USE SYMBIOTIC
  CYANOBACTERIA TO HELP PRECIPITATE THEIR SKELETON
• (3) SYMBIOTIC CYANOBACTERIA ARE A SOURCE OF BOTH
  OXYGEN AND FOOD
• (4) THE HEAVY EXOSKELETON OF HYPERCALCIFIED
  DEMOSPONGES CAN SCREEN OUT ULTRAVIOLET LIGHT

13
HYPERCALCIFIED DEMOSPONGES

• THEY GENERALLY HAVE
• (1) MODULAR GROWTH
• (2) AN EXTERNAL SKELETON OF SOLID ARAGONITE (MORE
  RARELY Mg-CALCITE) FORMED ON THE
  PREVIOUS MODULE.

14
Aragonite vs. Calcite Seas(Ries, Stanley and
Hardie, 2006)
15

• HERE ARE SOME PERMIAN HYPERCALCIFIED DEMOSPONGES
  THAT SURVIVED THE END-PERMIAN EXTINCTION

16
GIRTYOCOELIA
FINKS RIGBY, 2004
17
CYSTAULETES
FINKS PHOTO
18

• HERE IS ONE COMMON HYPERCALCIFIED DEMOSPONGE THAT
  DID NOT SURVIVE THE END-PERMIAN EXTINCTION,
  ALTHOUGH CLOSE RELATIVES DID.

19
GUADALUPIA
FINKS PHOTO
20

• GUADALUPIA MAY NOT HAVE SURVIVED BECAUSE THE
  UPPER SURFACE LACKED AN EXOSKELETON TO SCREEN OUT
  ULTRAVIOLET LIGHT.

21
Atmospheric O2 and CO2 Through Time(Huey and
Ward, 2005)
22

• DEMOSPONGES ARE THE ONLY METAZOA TODAY THAT HAVE
  SYMBIOTIC CYANOBACTERIA

23

• IF THE PERMIAN HYPERCALCIFIED DEMOSPONGES HAD
  SYMBIOTIC CYANOBACTERIA, THEIR PHOTOSYNTHETIC
  OXYGEN MIGHT HAVE ENABLED THEM TO SURVIVE ANOXIA
• THEY MAY HAVE HAD SYMBIOTIC CYANOBACTERIA TO HELP
  THEM SECRETE THEIR BASAL SKELETON OF CaCO3

24

• 2HCO3- Ca ? H2O CaCO3? CO2 ?
• Precipitation of CaCO3
• n CO2 n H2O? (CH2O)n nO2 ?
• Photosynthesis

25

• RECENT DEMOSPONGES ALSO FEED ON THEIR SYMBIOTIC
  CYANOBACTERIA

THIS COULD ALSO HAVE HELPED THE PERMIAN
HYPERCALCIFIED DEMOSPONGES TO SURVIVE THE
EXTINCTION EVENT
26
VERONGIA SP.
FRED ADELL
27
CYANOBACTERIA IN VERONGIA AEROPHOBA
SARA VACELET, 1973
28
ANTARCTIC IMPACT (VON FRESE POTTS, 2006) AND
RESULTANT SIBERIAN FLOOD BASALTS ARE AN ADEQUATE
CAUSE FOR HYPOXIA
29
Paleomap Project Christopher R. Scotese,
2003 http//www.scotese.com/info.htm
END PERMIAN EARTH
,
30
MERCURY CALORIS BASIN IMPACT
STRAUM SPRAGUE, 2003
31
Mars Orbiter Laser Altimeter NASA
32
THE IMPACTOR MAY HAVE LOOKED LIKE THIS. PHOEBE,
A MOON OF SATURN, MAY BE A CAPTURED KUIPER BELT
OBJECT, ITS SURFACE IS CO2 ICE. (NASA, CASSINI
ORBITER)