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January 2003
January 31, 2003
Upbeat for the Year of Chemistry
"The Kiss - Magic and Chemistry" is the title of an interactive exhibition that opened yesterday in Berlin. This represents a prelude to the "Year of Chemistry" - 2003, proclaimed by the federal Minister of Research, Bulmahn. Cooperative partners in this effort include "Wissenschaft im Dialog" (Dialogue in Science), the "Stifterverband für die Deutsche Wissenschaft" (association of benefactors for German science), as well as various chemistry organizations from the scientific and economic sectors.
As in past years, a "Summer of Science" will be organized again in 2003. It will run from the 16th to 22nd of September in Mainz. The Research Centre Ocean Margins (RCOM), including MARUM, will also be involved. The RCOM was highly successful during last year's "Year of Geosciences" with the "Marine Research Adventure" project. The exhibition was installed on a 105-meter long inland ship, and visited 62 cities. The present plan for the summer of 2003 is for the ship to sail along the Rhine with a chemistry exhibition and to dock in Mainz during the "Summer of Science". The Reseach Centre will introduce its experience ; it will both organise the ship`s schedule and administrate logistical tasks.
January 24, 2003
Surprising climatic changes
Our climate has not been as stable over the past 11,000 years as many of us might assume. That is the message of an article in the recent edition of "Nature" (Vol. 421, pp. 354-357, pp. 324-325). Climate researchers from India and the US document this with a sediment core that was drilled in 800 meters of water off Oman in the northwestern Indian Ocean. As one part of their work the researchers analyzed microfossils called foraminifera which they found in their core. The work was part of the international Ocean Drilling Program.
In summer the weather in this subtropical region is dominated today by the southwest monsoon. The winds blow northeastwardly over the warm water and accumulate moisture, which brings heavy and sometimes catastrophic rainfall to the Indian subcontinent. Farmers benefit as the monsoon waters their fields.
The "Nature" authors show that during the last 11,000 years the southwest monsoon system has collapsed seven times. When they compared their measurements with data from the North Atlantic region it became surprisingly clear that each time the monsoon collapsed there was a cold spell in the distant North Atlantic. Slightly diminished solar input could have been the cause for these teleconnected climate anomalies.
"The results presented by our colleagues are an interesting contribution to the current debate about long-term linkages of different climatic subsystems and their causes", comments Dr. Helge Arz. The geoscientist, who is working at the Research Center Ocean Margins Bremen, annotates: "Although we have some evidence for a close climatic coupling between the Arabian Sea and the North-Atlantic region on an interannual and decadal basis, palaeoclimatic observations, which would approve this on a longer term, were missing so far. Results from our own studies in the tropical Atlantic and in the northern Red Sea offer further potential to complete this picture."
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- January 31, 2003
- January 24, 2003
- January 17, 2003
Remnants of foraminifera from the sea-floor: The calcerous microorganisms archivate information about water temperatures for the period they lived in.
This foraminifera species indicates that at a certain time cool nutrient rich water from deeper ocean levels penetrated to the surface.
January 17, 2003
Heating up the debate about a cooling continent
Antarctica - the coldest of all our continents - is nearly completely covered by an ice sheet that, on the average, is about 2,000 meters thick. It is commonly accepted that the formation of Antarctica`s glaciers set in about 34 million years ago. It is also believed that the tectonically induced splitting up of the supercontinent Gondwana is the reason for the general cooling. Near the end of this process Antarctica was separated from Australia and South America. Thereby new ocean gateways opened, providing a pathway for the cool circumpolar current, which thermally isolated Terra Australis.
In this week`s edition of "Nature" Robert M DeConto and his co-worker David Pollard introduce a serious challenge to this kind of thinking. By modelling the southern atmosphere, ocean, ice sheet and sediment, they found that a decline in CO2 first led to the formation of small ice-caps. "According to our simulation the opening of Southern Ocean gateways plays a secondary role in this transition, relative to CO2 concentration", the US-based scientists state.
"The results published by our American colleagues take into account the interdependencies between the atmosphere, the greenhouse gas carbon dioxide, and the ice shield", comment Dr. Gerrit Lohmann and Dr. Martin Butzin. These climate modellers, who are working for the DFG Research Center Ocean Margins, remark: "The effects of open ocean passages and the heat transport effected through ocean currents are taken into account only indirectly. On the basis of this study, an assessment of the relative importance of ocean currents and atmospheric carbon dioxide to explain long term climatic shifts is only possible to a certain limit."
Modelling studies at the Research Center indicate that only a combined consideration of all ocean passages provide a key in order to understand the climatic history of Antarctica."
- January 31, 2003
- January 24, 2003
- January 17, 2003
Which role do ocean currents play in the process of the glaciation of Antarctica? Is it finally all a matter of decreasing atmospheric carbon dioxide?
See Nature, Vol. 421, p. 245-249, p. 221-223
Dr. Gerrit Lohman, climate modeller at the DFG-Research Center Ocean Margins