> Research > Programs and projects > Theme 1 & 2

Subproject 2, the palaeoecological component
Project leader: Prof. dr. H. Brinkhuis, Prof. dr. A. F. Lotter
Researcher(s): Dr. J. Barke
Starting date: 1-sep-06

Abstract
Recent Arctic drilling revealed that an unprecedented Azolla bloom occurred while the Arctic Basin was highly freshwater-stratified and anoxic. This bloom is precisely coeval (at ~49-48 Ma) with a global shift towards heavier δ13C values of deep marine waters, where climatic trends towards the modern icehouse began. At the same time freshwater spills carrying Azolla from the Arctic reached all Nordic seas, possibly influencing proto-Atlantic oceanic overturning. The conjunction of these events fuel the idea that a freshwater Arctic, massive blooms of Azolla, and enhanced carbon burial in a major anoxic oceanic basin over hundreds of thousands of years might indeed have contributed significantly to reducing atmospheric CO2. Yet, many questions concerning the Arctic depositional setting, timing and aerial extent, but also concerning Eocene Azolla palaeobiology, ecology and geography remain unanswered. Along the scope of the DARWIN Azolla project, we need to better document and understand (1) the geographical extent of the Azolla pulses and their timing, (2) the Arctic depositional conditions, (3) the palaeogeography and (4) palaeoecology of Azolla species involved, and (5) a multitude of taphonomic and degradation aspects, notably to (6) provide context for the subprojects 1 & 3.

Publications
Speelman, E.N., van Kempen, M.M.L., Barke, J., Brinkhuis, H., Reichart, G.J., Smolders, A.J.P., Roelofs, J.G.M., Sangiorgi, F., de Leeuw, J.W., Lotter, A.F., Sinninghe Damsté, J.S. (2009). The Eocene Arctic Azolla bloom: environmental conditions, productivity and carbon drawdown . Geobiology7 (2): 155-170.
Darwin Center authors: Barke J., Brinkhuis H., van Kempen M. M. L., Lotter A. F., Reichart G. J., Roelofs J. G. M., Sinninghe Damsté J. S., Speelman E. N.

Margaret E. Collinson, Judith Barke, Johan van der Burgh, Johanna H.A. van Konijnenburg-van Cittert (2009). A new species of the freshwater fern Azolla (Azollaceae) from the Eocene Arctic Ocean. Review of Palaeobotany and Palynology155: 1-14.
Darwin Center authors: Barke J.

Margaret E. Collinson, Judith Barke, Johan van der Burgh, Johanna H.A. van Konijnenburg-van Cittert, Claus Heilmann-Clausen, Lauren E. Howard, Henk Brinkhuis (2010). Did a single species of Eocene Azolla spread from the Arctic Basin to the southern North Sea?. Review of Palaeobotany and Palynology159: 152-165.
Darwin Center authors: Barke J., Brinkhuis H.

Judith Barke (2010). Palaeoecological and palaeoclimatological implications of the Eocene Northern Hemisphere Azolla phenomenon.
Darwin Center authors: Barke J.

Barke, J., Abels, H.A., Sangiorgi, F., Greenwood, D.R., Sweet, A.R., Donders, T., Reichart, G.-J. , Lotter, A.F., Brinkhuis, H. (2011). Orbitally forced Azolla blooms And Middle Eocene Arctic hydrology: Clues from palynology . GeologyVolume 39, Issue 5: 427-430.
Darwin Center authors: Barke J., Brinkhuis H., Lotter A. F., Reichart G. J.

Judith Barke, Johan van der Burgh, Johanna H.A. van Konijnenburg-van Cittert, Margaret E. Collinson, Martin A. Pearce, Jonathan Bujak, Claus Heilmann-Clausen, Eveline N. Speelman, Monique M.L. van Kempen, Gert-Jan Reichart, André F. Lotter, Henk Brinkhuis (2012). Coeval Eocene blooms of the freshwater fern Azolla in and around Arctic and Nordic seas. Palaeogeography, Palaeoclimatology, Palaeoecology337-338: 108-119.
Darwin Center authors: Barke J., Brinkhuis H., van Kempen M. M. L., Lotter A. F., Reichart G. J., Speelman E. N.