Plant Energy Transformations-Photosynthesis - …
By the 1850s, Germany was , and seminal discoveries and achievements came from German labs. As agriculture became industrialized, two nutrients were identified as key limiting resources as per : phosphorous and . Until 1909, humanity’s source of nitrogen for agriculture was manure. Guano was even the main source of nitrate for gunpowder when World War I began in 1914. After a century of failure by many eminent chemists, in 1909 made one of history’s most momentous breakthroughs when he . That energy-intensive process is responsible for half of humanity’s food supply today. It is also partly responsible for a great deal of water pollution, , and proliferation of weaponry. Haber has also been called the father of chemical warfare, as he was instrumental in , but he nevertheless won his Nobel Prize in 1918 for his nitrogen breakthrough. Phosphorus, which forms the , is the sole element that humanity has not found a substitute for in industrial civilization. Energy makes nitrogen and other elements more available or allows for substitution, while phosphorous must be mined or recycled. German chemical wizardry continued after World War I, and Germany was the center of science in the early 20th century. Relativity and quantum theory, the two pillars of today’s physics, were developed in Germanic nations, and Einstein, , , , , , and dominated physics in the early 20th century, with relatively minor contributions from American, British, and French scientists. From the first Nobel prizes awarded in 1901 to the rise of Nazi Germany in 1933, more than a third of the awards in and went to Germans, and if the Swiss, Dutch, Austrian, Danish, and Swedish laureates are added, they amount to well more than half, particularly for their theoretical work.
A collection of fossil dinosaur skeletons
There is also evidence that life itself can contribute to mass extinctions. When the eventually , organisms that could not survive or thrive around oxygen (called ) . When anoxic conditions appeared, particularly when existed, the anaerobes could abound once again, and when thrived, usually arising from ocean sediments, they . Since the ocean floor had already become anoxic, the seafloor was already a dead zone, so little harm was done there. The hydrogen sulfide became lethal when it rose in the and killed off surface life and then wafted into the air and near shore. But the greatest harm to life may have been inflicted when hydrogen sulfide eventually , which could have been the final blow to an already stressed ecosphere. That may seem a fanciful scenario, but there is evidence for it. There is fossil evidence of during the Permian extinction, as well as photosynthesizing anaerobic bacteria ( and ), which could have only thrived in sulfide-rich anoxic surface waters. Peter Ward made this key evidence for his , and he has implicated hydrogen sulfide events in most major mass extinctions. An important aspect of Ward’s Medea hypothesis work is that about 1,000 PPM of carbon dioxide in the atmosphere, which might be reached in this century if we keep burning fossil fuels, may artificially induce Canfield Oceans and result in . Those are not wild-eyed doomsday speculations, but logical outcomes of current trends and , proposed by leading scientists. Hundreds of already exist on Earth, which are primarily manmade. Even if those events are “only” 10% likely to happen in the next century, that we are flirting with them at all should make us shudder, for a few reasons, one of which is the awesome damage that it would inflict on the biosphere, including humanity, and another is that it is entirely preventable with the use of technologies .
Ice ages are an important realm of scientific investigation. Humanity’s colossal burning of Earth’s hydrocarbon deposits may well be delaying the ice sheets' return; they have been advancing and retreating in rhythmic fashion for . Today, the current pattern's accepted tipping point has been Earth’s orientation toward the Sun, particularly the , which has a roughly 100,000-year cycle. Although Earth’s orientation is universally considered to be the tipping point variable, it is not the only influence. The ultimate cause has been . about 35 mya due to its position near the South Pole and declining carbon dioxide levels. The current ice age began 2.5 mya and was likely initiated by the , which separated the Atlantic and Pacific oceans and radically altered oceanic currents. Also, . Those factors all contributed to the current ice age.