Is there a rock-bias to diversity patterns in the deep sea?
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This document analyzes the relationship between deep sea rock record and biodiversity patterns using coccolithophore data from the North Atlantic. It finds: 1) Deep sea species richness shows a linear rise over time with short-term fluctuations, while the deep sea rock record shows an exponential rise with short-term fluctuations. 2) The two time series are strongly and significantly correlated over both the long-term and short-term, indicating that deep sea biodiversity is correlated with the amount of sediment available to preserve fossils, similar to patterns on land. 3) The number of sample sites is a good predictor of deep sea species richness over time.
Is there a rock-bias to diversity patterns in the deep sea?
- 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 * *
- 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