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Late Cretaceous seasonal ocean variability from the Arctic
Andrew Davies1, Alan E S Kemp, Jennifer Pike
1National Oceanography Centre Southampton, School of Ocean and Earth Science, University of Southampton, Southampton, SO14 3ZH, UK.
Nature
|July 10, 2009
Summary
Records from the Cretaceous Arctic Ocean reveal seasonal diatom production, not upwelling, occurred in stratified waters. This suggests a potential model for future ocean productivity under global warming.
Area of Science:
- Palaeoclimatology
- Oceanography
- Marine Biology
Background:
- The Arctic Ocean is a key indicator of global climate change.
- Understanding past Arctic conditions is crucial for predicting future climate scenarios.
- Little is known about the Late Cretaceous Arctic Ocean's state during a greenhouse period.
Observation:
- A seasonally resolved sedimentary record from the Alpha ridge of the Arctic Ocean was analyzed.
- This record provides insights into the Cretaceous marine biological carbon pump.
- Analysis focused on primary production mechanisms and environmental conditions.
Findings:
- Seasonal primary production was dominated by diatoms, but not driven by upwelling.
- Production occurred in a stratified water column with specialized diatom blooms.
- Evidence suggests an ice-free summer but intermittent winter sea ice, indicating cooler temperatures than previously proposed.
Implications:
- Cretaceous production models may be relevant to future oceans experiencing increased stratification due to warming and higher CO2.
- Findings challenge previous hypotheses about Arctic Ocean temperatures during the Late Cretaceous.
- The study highlights the importance of studying past greenhouse periods for climate change research.
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