A new model suggests that inhospitable hydrodgen-sulphide rich waters could have delayed the spread of complex life forms in ancient oceans. The research, published online this week in the journal Nature Communications, considers the composition of the oceans 550-700 million years ago and shows that oxygen-poor toxic conditions, which may have delayed the establishment of complex life, were controlled by the biological availability of nitrogen.
In contrast to modern oceans, data from ancient rocks indicates that the deep oceans of the early Earth contained little oxygen, and flipped between an iron-rich state and a toxic hydrogen-sulphide-rich state. The latter toxic sulphidic state is caused by bacteria that survive in low oxygen and low nitrate conditions. The study shows how bacteria using nitrate in their metabolism would have displaced the less energetically efficient bacteria that produce sulphide meaning that the presence of nitrate in the oceans prevented build-up of the toxic sulphidic state.
The model, developed by researchers at the University of Exeter in collaboration with Plymouth Marine Laboratory, University of Leeds, UCL (University College London) and the University of Southern Denmark, reveals the sensitivity of the early oceans to the global nitrogen cycle. It shows how the availability of nitrate, and feedbacks within the global nitrogen cycle, would have controlled the shifting of the oceans between the two oxygen-free states potentially restricting the spread of early complex life.
Dr Richard Boyle from the University of Exeter said: "Data from the modern ocean suggests that even in an oxygen-poor ocean, this apparent global-scale interchange between sulphidic and non-sulphidic conditions is difficult to achieve. We've shown here how feedbacks arising from the fact that life uses nitrate as both a nutrient, and in respiration, controlled the interchange between two ocean states. For as long as sulphidic condition
'/>"/>
| Contact: Jo Bowler j.bowler@exeter.ac.uk 44-013-927-22062 University of Exeter Source:Eurekalert |
Related biology news :
1. Is nanosilver toxic?
2. Nitrogen from pollution, natural sources causes growth of toxic algae, study finds
3. Scientists turn toxic by-product into biofuel booster
4. How our cells cope with toxic small molecules
5. Chemistry resolves toxic concerns about carbon nanotubes
6. Discovered! The new species of Borneos enigmatic primate with a toxic bite
7. Potentially toxic flame retardants found in many US couches
8. Scientists take objective look at terms least toxic pesticides applied as last resort
9. Colorful wall hangings contain toxic substances
10. Corals attacked by toxic seaweed use chemical 911 signals to summon help
11. Sweet new approach discovered to help produce metal casting parts, reduce toxicity
| Copyright © 2003-2012 Bio-Medicine. All rights reserved. ABOUT | CONTACT US | DISCLAIMER | PRIVACY POLICY | TERMS AND CONDITIONS |  |