Increasing levels of greenhouse gas emissions may lead to large level extinction of marine life says a research by geologists that appeared in the Proceedings of the National Academy of Sciences (PNAS).
The research paper presented by Professor Thomas Wagner from Newcastle University and Professor Martin Kennedy from the University of Adelaide warns of mass extinction of ocean animals comparable to prehistoric periods.
The researchers have been researching the so called greenhouse oceans that suffer insufficient levels of oxygen and increased levels of temperature and carbon dioxide. They utilized the drilled samples of sediment layers that belong to the late Cretaceous Period (85 million years ago) from the ocean bed that lay off the West African coast for their research. They discovered large quantities of organic compounds of marine life entombed within deoxygenated layers of the deposits.
According to Professor Kennedy, the greenhouse gas effects over the earth along with rising temperatures and increased level of carbon dioxide in the air has depleted the level of oxygen in the water and that led to mass mortality of marine animals. He added that all the changes have happened rapidly instead of the normal geological time scales within a period of less than hundreds of years thus showing the fragile balance levels of oceans and their rapid response to changes in temperature and carbon dioxide levels. He said that the level of carbon dioxide in the atmosphere has almost doubled when compared to solar radiation during the last 50 years. He anticipates the increased level of carbon dioxide will have more disastrous consequences on ocean life, which in turn will trigger impacts on land living animals including humans.
According to Professor Wagner the dead zones are regularly occurring and growing in size over a number of oceans and seas all over the world. In such locations the sea water suffers from reduced levels of oxygen and increased levels of carbon dioxide and high level temperatures. The places also suffer from overflow of nutrient from farming and other factors.
The research as a flash of hope indicates that the nature itself responds to the increased level of greenhouse gas emissions by improving the oxygen concentration in the ocean after the hypoxic phase. This happens due to the carrying of soil-formed minerals and organic matters from the earth to oceans thus reducing the level of carbon dioxide from the oceans and the air.
Source: http://www.adelaide.edu.au/