Mass extinctions of the past preceded the rare trace element deficiency
The content of selenium dissolved in the water of the oceans, fell sharply the day before at least three mass extinctions of the past: silluriyskogo Ordovician (about 440 million years ago), Devonian (360 million years ago) and the Triassic (200 million years ago).
To such conclusions scientists have studied the composition of ancient sediments, preserved on a large, virtually oxygen-free depths of the oceans over 3.5 billion years. The publication presented a fresh issue of the journal Gondwana Research, a group paleogeology from Europe and Australia indicated that for the other elements of this can not be traced - only for a rare selenium.
By itself, this trace element is toxic in nature and is found in very low concentrations, "washed out" of the minerals under the influence of atmospheric oxygen. But in a variety of living organisms - including humans - it is practically irreplaceable role played by entering into the active sites of various proteins. Selenium is essential for the metabolism of fats and proteins, nucleic acids and carbohydrates, protect against reactive oxygen species, the synthesis of certain hormones, assimilation of iodine, etc.
It requires a lot of algae for photosynthesis reactions. So, by virtue of selenium it determines the life of the food pyramid, which is based on phytoplankton. Not surprisingly, the authors of the new work believe that it is a sharp deficiency of selenium may catastrophically "brought down" the ancient Earth's ecosystem. And if this is not the lack of trace elements led to the tragic mass extinction itself, then at least she could play a more important role.
Falling of selenium it could be caused by a decrease in the amount of free oxygen, which is necessary to the microcell might be allocated from minerals and convertible to a soluble form. In any case, the study authors noted that the lack of oxygen was observed before the mass extinctions of the past, and in the process, and after them.
The content of selenium dissolved in the water of the oceans, fell sharply the day before at least three mass extinctions of the past: silluriyskogo Ordovician (about 440 million years ago), Devonian (360 million years ago) and the Triassic (200 million years ago).
To such conclusions scientists have studied the composition of ancient sediments, preserved on a large, virtually oxygen-free depths of the oceans over 3.5 billion years. The publication presented a fresh issue of the journal Gondwana Research, a group paleogeology from Europe and Australia indicated that for the other elements of this can not be traced - only for a rare selenium.
By itself, this trace element is toxic in nature and is found in very low concentrations, "washed out" of the minerals under the influence of atmospheric oxygen. But in a variety of living organisms - including humans - it is practically irreplaceable role played by entering into the active sites of various proteins. Selenium is essential for the metabolism of fats and proteins, nucleic acids and carbohydrates, protect against reactive oxygen species, the synthesis of certain hormones, assimilation of iodine, etc.
It requires a lot of algae for photosynthesis reactions. So, by virtue of selenium it determines the life of the food pyramid, which is based on phytoplankton. Not surprisingly, the authors of the new work believe that it is a sharp deficiency of selenium may catastrophically "brought down" the ancient Earth's ecosystem. And if this is not the lack of trace elements led to the tragic mass extinction itself, then at least she could play a more important role.
Falling of selenium it could be caused by a decrease in the amount of free oxygen, which is necessary to the microcell might be allocated from minerals and convertible to a soluble form. In any case, the study authors noted that the lack of oxygen was observed before the mass extinctions of the past, and in the process, and after them.
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