'The freshwater threshold required to shift sheltered and semi-enclosed areas of the modern ocean into an anoxic mode are unknown but the progressive emission of greenhouse gases to the modern atmosphere is gradually shifting Earth towards a greenhouse mode with an accelerated hydrological cycle.'

'At present it is hardly possible to estimate where we are on the long-term climate trend but once the freshwater threshold is passed, a substantial impact on biochemical cycling of continental margins may be expected.'

Commenting on the Nature paper, Professor Wagner said that the majority of the world's population live in coastal areas, which were the most vulnerable to natural catastrophes as recorded in the geological record.

'Understanding the processes and feedbacks controlling carbon and nutrient cycling in the modern world and during past periods of extreme warmth is therefore critical to separate human impact on climate from natural variability and underpins the ability to adapt to future conditions,' he said.

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Contact: Professor Tom Wagner
thomas.Wagner@newcastle.ac.uk
44-191-246-4880
University of Newcastle upon Tyne
7-Sep-2005