1. Neuroprotecting globins in the marine mammal brain Photo credit: democraticunderground.com

2. What adaptations do they use in order to hold their breath for such a long, long time?

3. Mammalian breath hold capabilities ( in minutes) Human*1 Polar bear1.5 Sea otter5 Porpoise15 Seal15-28 Greenland Whale60 Sperm whale90 Bottlenose whale120 *Crazy Swiss man, Peter Colat, 19 min. 21 s Photo credit: news.discovery.com

4. Photo credit: puertogaleradive.com Basis for this field of research: Energy we think they gain from one breath << Energy we think they spend while submerged

5. Basis for this field of research: Energy we think they gain from one breath << Energy we think they spend while submerged If above is true, you would expect: Evidence heavy reliance on anaerobic metabolism Photo credit: puertogaleradive.com

6. Basis for this field of research: Energy we think they gain from one breath << Energy we think they spend while submerged If above is true, you would expect: Evidence heavy reliance on anaerobic metabolism Photo credit: puertogaleradive.com

7. Basis for this field of research: Energy we think they gain from one breath << Energy we think they spend while submerged Photo credit: puertogaleradive.com Then, above statement must not be true…

8. Basis for this field of research: Energy we think they gain from one breath << Energy we think they spend while submerged Photo credit: puertogaleradive.com Then, above statement must not be true… Now what?

9. Basis for this field of research: Energy we think they gain from one breath << Energy we think they spend while submerged Photo credit: puertogaleradive.com Then, above statement must not be true… Now what? Look for adaptations!

10. What researchers found: 1870 Paul Bert - limits  blood volume 1930s & 1940s - Body size Total blood volume RBC mass Hematocrit Muscle [myoglobin]

11. Figure credit: Hochachka and Somero 2002 What researchers found: 1870 Paul Bert - limits  blood volume 1930s & 1940s - Body size Total blood volume RBC mass Hematocrit Muscle [myoglobin]

12. Photo credit: doc.govt.nz Dive response concept: Apnea Bradycardia Peripheral vasoconstriction Hypometabolism Helps us understand balance: Energy in one breath Energy used in prolonged dive

13. Interrelatedness of dive response components: Apnea  Bradycardia

14. Interrelatedness of dive response components: Apnea  Bradycardia (even in humans)

15. Interrelatedness of dive response components: Apnea  Bradycardia  Drop in cardiac output (CO = stroke volume x heart rate (vol/min))

16. Drop in arterial BP Interrelatedness of dive response components: Apnea  Bradycardia  Drop in cardiac output 

17. Drop in arterial BP Interrelatedness of dive response components: Apnea  Bradycardia  Drop in cardiac output  X

18. BP remains stable Interrelatedness of dive response components: Apnea  Bradycardia  Drop in cardiac output while Vasoconstriction 

19. Figure credit: Hochachka and Somero 2002

20. BP remains stable Interrelatedness of dive response components: Apnea  Bradycardia  Drop in cardiac output while Vasoconstriction   Hypometabolism

21. BP remains stable Interrelatedness of dive response components: Apnea  Bradycardia  Drop in cardiac output while Vasoconstriction   Hypometabolism (energy saved in bypassing non-vital organs  2-3ºC drop in body temperature)

22. How would you monitor these responses?

23. Heart monitors Backpack cameras Lactate dehydrogenase levels Figure credit: Davis et al. 1999

24. Figure credit: Kooyman et al. 1981

28. Figure credit: Hochachka and Somero 2002

29. Photo credit: ctap4.org Dive response concept: Apnea Bradycardia Peripheral vasoconstriction Hypometabolism How do these relate to: Body size Total blood volume RBC mass Hematocrit Muscle [myoglobin]

30. Figure credit: Williams et al. 2000 Behavioral adaptations: Dive duration Gliding Resting

31. Proposing a new adaptation for the list…

32. Photo credit: wikipedia.com Globins Proteins with heme group Involved in oxygen binding and transfer Hemoglobin (Hb) Myoglobin (Mb) Cytoglobin (Cb) Neuroglobin (Nb)

33. Photo credit: brainviews.com Cerebral cortex Thin sheet of neural tissue Plays role in: Memory Attention Perceptual awareness Thought Language Consciousness

34. Researchers still think blood oxygen levels in diving mammals are too low to sustain activity…

35. Williams et al. 2008 Hypothesis: Enhanced levels of neuroprotecting globins are an additional adaptation for a diving lifestyle

36. Williams et al. 2008 Methods: Group globins: Circulating (Hb) Resident (Cb and Nb) Measure in cerebral cortex of 16 species Running, swimming, diving Prolonged mortality events Spectrophotometric determination mRNA expression

37. Williams et al. 2008 Results: Globin levels correlated with activity group Figure credit: Williams et al. 2008

38. Williams et al. 2008 Results: Hb and RNGs significantly higher in diving marine mammals compared to terrestrial species Figure credit: Williams et al. 2008

39. Williams et al. 2008 Results: RNG levels inversely correlated with dive duration Figure credit: Williams et al. 2008

40. Williams et al. 2008 Discussion: Elevated RNG and Hb levels are adaptations for activity type Enhance diving response Cope with low oxygen levels during prolonged dives Circulating and resident globins provide complementary support

41. Questions for Discussion How do you expect the following to interact with and effect adaptive globin responses? Body size Phylogenetic history Habitat Activity level What does hypoxia really mean? Post mortem sampling concerns… Standardize globin concentrations to total blood volume?