1. Is there a rock-bias to diversity
patterns in the deep sea?
Graeme T. Lloyd, Andrew B. Smith
and Jeremy R. Young

2. Fossil record is our only record of the
diversification of life

3. Diversity correlates with rock record on
land…
Peters and Foote 2001 Smith and McGowan 2007

4. …but what about the deep sea?
• Widely regarded as the best record we have:
– Larger spatial extent than land
– Abundant and widespread taxa
– Near continuous sedimentation
– Well studied (e.g. DSDP/ODP/IODP)

5. The database
• Study group is Coccolithophores
• Novel compilation from North Atlantic
• Compiled from 40 years ODP/DSDP
data
• 46,538+ occs from 14405+ samples
• High temporal resolution (nanno zones)
Questions:
• What is the deep sea diversity pattern?
• What is the deep sea rock pattern?
• Are the two correlated to any degree?

6. Deep sea species richness

7. Deep sea rock record

8. Correlation tests
• First both time series were log-transformed
• Long term test:
– Simple correlation
• Short term tests:
– First differences (absolute)
– Moving average differences (relative to long
term trend)
• Degree (rho) and significance (p) of
correlations determined using Spearman
rank

9. Deep sea long-term correlation

10. Deep sea short-term correlation I

11. Deep sea short-term correlation II

12. Modeling

13. Modeling results

14. Modeling results
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15. Deep sea conclusions
Questions:
• What is the deep sea diversity pattern?
– Linear rise with short-term fluctuations
• What is the deep sea rock pattern?
– Exponential rise with short-term fluctuations
• Are the two correlated to any degree?
– Yes, strongly and significantly, over both long-term
and short-term
– N sites is a good predictor of species richness

16. Other diversity curves

17. Other diversity curves

18. Other diversity curves