These are fundamental and burning questions on the society's agenda. Hurricane Katrina and other natural catastrophes in recent years have shown how vulnerable mankind is in the face of nature. Professor Tom Wagner of Newcastle University, England, led a cross-disciplinary study of geological records combined with climate modeling to shed new light on the mechanisms and processes that led to repetitive rapid climatic change with major impact on the ocean during past greenhouse conditions.
By analysing sediments laid down on the ocean floor about 85m years ago in the Cretaceous, the research team found evidence that Cretaceous greenhouse climate was highly variable and repeatedly resulted in major changes in ocean chemistry and deep circulation causing disastrous consequences for marine ecosystems. These extreme conditions fostered massive burial of dead organic matter from marine species, such as algae and plankton, at the sea floor, leading to the formation of distinct sediments, "marine black shale", also well known as the world's primary source for oil and gas.
Professor Wagner and colleagues uncovered evidence of the mechanisms that drove rapid and repetitive climate change by studying the quantity and content of proxy parameters in black shale in a core of sedimentary rock drilled out of the ocean bed, off Africa's Ivory Coast, and comparing these results with data from a global climate model.
The model data were used to quantify the freshwater run-off from tropical Africa into the equatorial Atlantic, where the core has been drilled, and to
Contact: Professor Tom Wagner
University of Newcastle upon Tyne