Expanded Analysis of Catastrophic Soil Erosion during the End-Permian Biotic Crisis
Expanded Analysis of Catastrophic Soil Erosion during the End-Permian Biotic Crisis
Scientists have come to many conclusions in explaining the mass extinction of the end-Permian era, and Mark Sephton and his geological team have contributed greatly to the understanding and explanation of the cause of the biotic crisis. After doing organic geochemical analyses of organic matter in northern Italy, Sephton et al. have discovered the DNA (polysaccharides) of land based organisms in sedimentary rock dating from the marine Permian-Triassic transition period. It was after studying these polysaccharides Sephton et al. hypothesized that within the Permian-Triassic transition there were volcanic eruptions which caused disruption of atmospheric chemistry, leading to the death of land vegetation which began to collect in excess and which finally resulted in a gigantic soil-erosion into the oceans which killed Permian marine life by hypoxia and anoxia.
In Val Badia in northern Italy, Sephton et al. collected sedimentary rock samples dating back to the end-Permian era and ran tests trying to detect any organic-geochemical evidence of terrestrial ecosystem collapse. This was tested by determining if the sediments had been deposited in shallow marine environments which had taken an input of major land-plant debris at anytime. The organic compounds and carbon isotopes compounds were confirmed by Sephton et al. using high-resolution gas chromatography – mass spectrometry. The organic soil matter was specifically furan structures which are produced by the dehydration of cellulose and, when found in fossilized organic matter, which are usually presumed to be the remains of dehydrated polysaccharides. This DNA implied that the initial soil conditions were very good for burying and preserving eroded organic soil matter in the marine ecosystem.
To further support the hypothesis of the end-Permian Soil Crisis, Sephton et al. needed evidence of excessive soil erosion from other land masses that had been a part of the single land mass of Pangaea. Hence the reference from Retallack, (2005) of pedoliths or re-deposited soils found in Antarctica, eastern Australia, and South Africa, as this similar evidence affirms the validity of Sephton’s et al. hypothesis and throws doubt on the idea that it was merely an isolated incident in northern Italy. While geochemical and geophysical data have been used in the past to provide an explanation for the huge Permian extinction, believed to be the result of a meteorite impact similar to that of the dinosaur extinction of the Cretaceous-Tertiary boundary, the question still remains as to what acted as the catalyst for the cascade of volcanic eruptions. While a large enough meteorite impact to the Earth could have set the stage for this tectonic work to occur, both Sephton et al. and other members of the larger scientific community at large refute such an impact as being solely responsible for the mass extinction. Koeberl et al., who are cited within Sephton’s article, conducted similar sedimentary chemical analysis and also suggest that a geochemical event of a volcanogenic disturbance greatly altered atmospheric chemistry.
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Evidence shows volcanic activity specifically occurred within the Siberian Traps. In fact, Benton, MJ (2007) cited Sephton et al. argues that the massive eruptions released excessive amounts of carbon dioxide and the atmospheric acidification change caused acid rain which killed plants and led to stripping of soils. This is most likely the cause of the widespread end-Permian soil erosion according to a fellow field scientists Visscher et al., (1996) and Maruoka et al., (2003). The soil stability and soil samples showing reduced bacteria content and decreased polysaccharide decomposition rates was most likely the result of the acidification. The volcanic emissions are the most probable reason for the elevated atmospheric carbon dioxide concentrations.
This in turn presented very serious implications for the marine ecosystem. With an excess of nutrients from the soil erosions pouring into the marine biota, widespread eutrophication began to occur and in stratified waters, the decaying of sunken dead phytoplankton lead to hypoxia, where dissolved oxygen in bottom waters was below the necessary level to sustain most animal life, and which ultimately led to anoxia. Then, in shallow marine waters, excessive riverine clay and silt deposits caused increased turbidity. With increased turbidity there was a reduction in an available energy source for marine organisms to use. Limited light penetration meant impaired photosynthesis which stunted plant growth and depleted dissolved oxygen which contaminated marine habitats for organisms which relied on an oxygen supply in the water. With inhibited reef buildup and asphyxiated organisms, the marine food web collapsed, leading to mass extinction.
Studies remain to be done on the worldwide effects of extensive volcanic activity in Siberia. Nonetheless, the scientific method has been strongly upheld in this study. The observation and description of the mass extinction can be studied and replicated by anyone anywhere. The hypothesis to explain the phenomena was founded on the natural world. Most importantly the hypothesis was able to predict the existence of the same phenomena, with similar results from the new observations and evidence in other regions of the world, with great accuracy. Finally, when several independent experimenters of the same field reviewed the findings and conducted properly replicated experiments, their findings were similar and pointed to the same conclusion. In time, if this hypothesis continues to hold true, Sephton et al. hypothesis may become as widely accepted of a theory in the scientific community for explaining the end-Permian mass extinction as the theory of gravity or Plate Tectonics.
The mainstream press article from the BBC is a highly simplified interpretation and analysis of Sephton et al. article. The simplification is so excessive that a simple term such as mass extinction, which would be presumed to be a common sense word, is referred to within the article as the “great dying.” However, the article also provides context for things that many people many never have known before reading the article, such as the fact that end-Permian coil crisis that occurred 200 million years ago set the stage for the dinosaurs 185 million year long domination over the world. While it is a fact that a scientist would already understand, reader might not know it as well, so the article associated it with something as familiar as the dinosaurs. Most importantly, the mainstream press article takes all the main points of Sephton et al. article and condenses them into concise points that even a person with an 8th grade reading level could easily understand. The mainstream press article has taught me that the scientific method is only as strong as its ability to share its discoveries with the general public.
Science is defined as an objective, disciplined methodology for investigating natural phenomena. Science is broken up into many different disciplines that can be studied in life, so scientists are really nothing more than people who possess expert knowledge in a particular discipline. However, when scientists use the scientific method in their efforts to extend and deepen our understanding of the physical world, the everyday person usually finds him or herself lost in translation. If the discoveries of the study cannot be shared with the greater public, they really serve no purpose. As well, the scientific method becomes inherently meaningless. If the principles and empirical processes of discovery and demonstration of scientific investigation are exclusive, there is no opportunity for replication and further validation of the hypotheses. As well, if no one can understand the discoveries of the studies, the general public will find no relevance in them or be able to establish a connection with, understanding of, and appreciation for the scientific process. Without publicity, science is just an extensive secret serving no function to society. It’s also a two way street. Many times the scientific process is funded and executed through the means of answering pressing questions of society, and if not everyone in society can understand it, many will see it fit to take up the bill. The mainstream media acts as the essential middle man in bridging the great gap between the scientific community and the predominately undereducated general public.
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