The Eocene Arctic Azolla bloom: environmental conditions, productivity and carbon drawdown

@article{Speelman2009TheEA,
  title={The Eocene Arctic Azolla bloom: environmental conditions, productivity and carbon drawdown},
  author={Eveline N. Speelman and Monique M. L. van Kempen and Judith Barke and Henk Brinkhuis and Gert‐Jan Reichart and Alfons J. P. Smolders and Jan G. M. Roelofs and Francesca Sangiorgi and Johannes de Leeuw and Andr{\'e} F. Lotter and Jaap S. Sinninghe Damst{\'e}},
  journal={Geobiology},
  year={2009},
  volume={7}
}
Enormous quantities of the free‐floating freshwater fern Azolla grew and reproduced in situ in the Arctic Ocean during the middle Eocene, as was demonstrated by microscopic analysis of microlaminated sediments recovered from the Lomonosov Ridge during Integrated Ocean Drilling Program (IODP) Expedition 302. The timing of the Azolla phase (~48.5 Ma) coincides with the earliest signs of onset of the transition from a greenhouse towards the modern icehouse Earth. The sustained growth of Azolla… 

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References

SHOWING 1-10 OF 75 REFERENCES
Cyclicity in the middle Eocene central Arctic Ocean sediment record: Orbital forcing and environmental response
[1] Continuous X-ray fluorescence scanning of middle Eocene (� 46 Ma) core M0002A-55X (� 236–241 m composite depth), recovered during Integrated Ocean Drilling Program Expedition 302, revealed a
A Siliceous Microfossil View of Middle Eocene Arctic Paleoenvironments
Integrated Ocean Drilling Program (IODP) Expedition 302, “The Arctic Coring Expedition” (ACEX), unearthed the most significant find of Paleogene siliceous microfossils in nearly 2 decades. 100 m of
Episodic fresh surface waters in the Eocene Arctic Ocean
TLDR
Palaeogene sediments obtained during the Arctic Coring Expedition are analysed, showing that large quantities of the free-floating fern Azolla grew and reproduced in the Arctic Ocean by the onset of the middle Eocene epoch and that onset and termination of the Azolla phase depended on the degree of oceanic exchange between Arctic Ocean and adjacent seas.
Tracking nutrient and productivity variations over the Last Deglaciation in the Arctic Ocean
We have reconstructed the surface water environment of the Arctic Ocean over the last ∼ 50,000 years using measurements of the organic nitrogen and carbon isotope ratios, carbonate and total organic
Anoxia and high primary production in the Paleogene central Arctic Ocean: First detailed records from Lomonosov Ridge
Except for a few discontinuous fragments of the Late Cretaceous/Early Cenozoic climate history and depositional environment, the paleoenvironmental evolution of the pre‐Neogene central Arctic Ocean
Salinity of the Eocene Arctic Ocean from oxygen isotope analysis of fish bone carbonate
Stable isotope analysis was performed on the structural carbonate of fish bone apatite from early and early middle Eocene samples (∼55 to ∼45 Ma) recently recovered from the Lomonosov Ridge by
Eocene bipolar glaciation associated with global carbon cycle changes
The transition from the extreme global warmth of the early Eocene ‘greenhouse’ climate ∼55 million years ago to the present glaciated state is one of the most prominent changes in Earth's climatic
High rates of N2 fixation by unicellular diazotrophs in the oligotrophic Pacific Ocean
TLDR
Direct measurements of 15N2 fixation by small diazotrophs in various parts of the Pacific Ocean, including the waters off Hawaii where the unicellular diazOTrophs were first characterized, show that N1 fixation by unicells can support a significant fraction of total new production in oligotrophic waters.
...
1
2
3
4
5
...