Dinosaur Killers

by Popoff, Alexander

  Lower or higher levels of oxygen make the environment quite different: if the oxygen of the modern atmosphere is under 15 percent, fires would not burn; if the oxygen level is higher than 25 percent, even wet organic matter would burn easily and constant huge fires would rage on the Earth.

  Atmospheric scientist Richard Turco noted that: “At higher oxygen concentrations (perhaps 30% or more of air) vegetation becomes explosively combustible, so combustion would act to limit the build-up of oxygen.”

  The present atmospheric level of oxygen is 21 percent; nitrogen is 78 percent; and carbon dioxide is only 0.035%.

  James Lovelock, author of the Gaia hypothesis, which states that Earth and everything on it constitutes a single, self-regulating living entity, reported that the probability of a lightning flash to start fire increases 70% for each 1% rise in oxygen concentration above 21%. Lovelock’s numbers are based on lab work by a colleague, Andrew Watson of Reading University.

  Above 25% oxygen, most terrestrial areas would be in constant fires, which would last to the almost total destruction of the vegetation or when the oxygen concentration decreases.

  Lovelock wrote in his book The Ages of Gaia, “Oxygen has been constant at 21% by volume in the Phanerozoic (the age of plants and animals). The evidence of this constant high concentration is the presence in the sediments of layers containing charcoal. These can be found as far back as 200 million years. The presence of charcoal implies fires, probably forest fires. This sets sharp limits on atmospheric oxygen abundance. My colleague, Andrew Watson, showed that fires cannot be started, even in dry twigs, when oxygen is below 15%; above 25% fires are so fierce that even the damp wood of a tropical rain forest would burn in an awesome conflagration. Below 15% there would be no charcoal; above 25% no forests. Oxygen is 21% close to the mean between these limits.”

  In the specific Mesozoic hothouse world, with a much denser atmosphere and high amounts of oxygen and carbon dioxide, animals and plants grew much larger and were more numerous.

  The huge reptiles and insects could fly only in a dense atmosphere with higher amounts of oxygen. They needed more fuel (oxygen) for their metabolic engines and thicker air to support their wings.

  Robert Dudley from the Animal Flight Laboratory at the University of California performed experiments in order to establish if flies raised in hyperbaric conditions underincreased atmospheric pressure (which have higher partial pressure of oxygen),would grow larger than their normal counterparts. Dudley reported that the average body mass of fruit flies of both sexes in the experimental line was significantly greater than that of insects in the control line.

  Increased levels of oxygen and denser atmosphere result in larger sizes of animals’ species. Lower oxygen percentage and thinner air result in smaller animals.

  Matthew Clapham and Jered Karr from the University of California have analyzed more than 10,500 fossilized insect wings. Their data set clearly show that the maximum wingspans of flying insects neatly tracked the oxygen in the atmosphere for their first 150 million years of evolution. As the oxygen levels reached its peak during the Permian, the insects were largest; as levels later fell, the insects shrank.

  After that, the insects didn’t follow the oxygen levels. They even got smaller because of the advance of the birds. Smaller insects were fast and maneuverable, and survived bird attacks.

  The amounts of oxygen available to the metabolism of the Mesozoic animals depended not only on the percentage of this gas in the atmosphere, but also on the air pressure. Higher pressure also means more available oxygen.

  Even if the percentage of the oxygen is the same, but the air pressure is higher, the amount of oxygen in a given volume is higher. The amount of gas in a given volume is determined by the pressure and the temperature. As the air pressure increases, the partial pressure of oxygen increases, too.

  The Cretaceous atmosphere was far richer in oxygen than it is today.

  During the Mesozoic there was more oxygen available for metabolism of the animals—a higher percentage of oxygen, higher pressure, higher temperatures. The higher temperatures and the higher pressure made the utilization of oxygen much easier.

  If an animal breathes air under higher pressure, such as inside a hyperbaric chamber (or as it was during the Mesozoic), the amount of oxygen in its blood increases significantly.

  The breathing system of the dinosaurs and their hemoglobin were adapted to much higher levels of oxygen and a denser atmosphere. They were different than in modern animals. If we had dinosaur hemoglobin samples, we would know much more about their metabolism and the link between oxygen levels and the extinction of the species.

  Hemoglobin is an oxygen-transport protein that gives blood its red color.

  The fast drop of the oxygen level and the air pressure should be responded by the animal respiratory system with changes of the breathing system and the hemoglobin. The mutations should happen very fast and should be adequate in order for the animals to survive in the severe environment after the comet impact and to cope with the fierce competition for food.

  About 80 to 90% of the metabolic energy of animals comes from oxygen and only 10 to 20% from food.

  Metabolism is a generic term for chemical reactions that break down food to provide energy for the operation of an organism—to grow and reproduce, maintain the structures, and respond to the environment. The metabolism of food requires a constant supply of oxygen.

  Fat, carbohydrates (commonly referred to as sugars), and proteins should combine with oxygen in order for organisms to produce energy. Animals have to “burn” the food.

  1 gram of carbohydrate (sugar) requires 0.8 liters of oxygen and yields 4.1 kcal.

  1 gram of protein requires 1.2 liters of oxygen and yields 5.5 kcal.

  1 gram of fat requires 2.2 liters of oxygen and yields 9.5 kcal.

  The Mesozoic species, especially the dinosaurs, took advantage of the large amounts of oxygen, the abundant food, and the steady, warm climate, with only slight seasonal variations.

  Why there were no seasons, or only minor seasonal changes, during the Mesozoic? Because of the atmosphere. The dense atmosphere with higher levels of carbon dioxide was protecting the Earth like a winter jacket.

  The metabolism of the Mesozoic fauna was different from the modern one because the atmosphere they breathed was different.

  The large dinosaurs did not need to be truly warm-blooded because they had enough energy (lots of oxygen and food) at their disposal, a steady, warm climate, and almost no rival species outside the dinosauria.

  In the article “Resources and energetics determined dinosaur maximal size,” published in 2009 in Proceedings of the National Academy of Sciences, Brian K. McNab wrote, “I conclude that large herbivorous and carnivorous dinosaurs were homoeothermic as a result of their very large masses, but they were not characterized by rates of metabolism that would be expected in mammals or flighted birds, which suggests that intermediate body temperatures that varied with body mass probably characterized sauropods and theropods.”

  “The presence of rates of metabolism in dinosaurs intermediate to those of most living reptiles and living birds and mammals is supported by a consideration of areas occupied, population sizes, theropod coexistence, and an analysis of bone oxygen isotopes, which probably led to population biomass densities appreciably greater than found today in East African mammals.”

  Not being truly warm-blooded was a way for them to resolve the problem with the overheating of their huge bodies in the hot, wet Mesozoic climate. The removal of body heat is more difficult in a hotter, wetter, and denser atmosphere. The large dinosaurs would have been very troubled, if they were truly warm-blooded.

  Avian dinosaurs became warm-blooded and smaller in order to fly more efficiently.

  Metabolism was not the same in all dinosaurs. Some were more warm-blooded than others. Probably most of them had a specific dinosaurian metabolism.

  The Mesozoic atmosphere, with much higher amounts of ca
rbon dioxide and higher atmospheric pressure, helped plants grow bigger and faster. With lots of plants, herbivorous dinosaurs thrived, providing lots of food for their carnivorous cousins. Both plant-eaters and meat-eaters grew fearsome because of the access to large amounts of energy—food and oxygen.

  Mammals, the present dominant species, can’t reach the giant size of the Mesozoic dominant species, the dinosaurs, because the modern atmosphere is different—a lower percentage of oxygen, lower air pressure, lower amounts of carbon dioxide.

  Dinosaurs were very well adapted to the Mesozoic period. They ruled over a specific world.

  Dinosaurs couldn’t live in the present world for many reasons—different atmosphere, different microbes, etc. Thus, present-day dinosaurs should be genetically modified in order to survive in the contemporary ecosystem. It’s not possible to reconstruct in open habitat the original authentic flora and fauna of the Mesozoic world as Michael Crichton did in his novel Jurassic Park.

  THE Energy Problem

  What made dinosaurs dominant became their major drawback during the K comet events.

  For the Mesozoic plants and animals, the Cretaceous catastrophe was a metabolic disaster.

  During the K comet events, the oxygen in the air decreased abruptly. Because of the tremendous amounts of inflammable volatile elements (frozen gases and liquids) and the very high velocity, the impact plumes and the column of superheated gases ejected part of the atmosphere into space. With partially lost atmosphere, the air pressure became lower.

  In his article “Atmospheric erosion induced by oblique impacts,” V. Shuvalov wrote, “In general, high velocity comets produce stronger atmospheric erosion than asteroids impacting the Earth with lower velocities.”

  “In closing, it should be noted that a considerable part (more than a half for the modern Earth) of impactors fall into the ocean. The presence of a water layer can substantially change the parameters of the impact plume and, consequently, change the mass of escaping air. The results probably depend on the ratio of projectile size to water depth.”

  The Chicxulub impact was in shallow waters. The K comet was fragmented, and it is possible that several other chunks hit the ocean.

  Part of the atmosphere was lost in space; part of the oxygen burned during the impact events. Most of the marine and land oxygen producing plants were destroyed.

  The oxygen in the deflated post-impacts atmosphere was decreasing because most of the oxygen-producing plants were annihilated by wildfires; the tremendous global thermal pulse; heavy acid rains; the impacts, and the acidification of the oceans. The lower sunlight levels due to massive dust clouds from the impact blast, volcanoes, prolonged fossil-fuel fires, cometarydust, and wildfires reduced the oxygen produced by the dwindling land and marine plants. The ocean phytoplanktons are major oxygen producers. There was agreat loss of phytoplankton.

  “At the Cretaceous-Paleogene boundary, 93 percent of the nanoplankton went extinct,” said Timothy J. Bralower, professor of geosciences at the University of California. “Nanoplankton are the base of the food chain in the ocean. If they go extinct, other, larger organisms that feed on them have problems.”

  Bralower and his team found that extinction levels correlate very well with latitude. The highest rate of extinctions was in the Northern Hemisphere, with decreasing extinction levels in the Southern Hemisphere. The impacts were in the Northern Hemisphere.

  The oxygen deprivation after the impact events did not kill off the species directly. It just gave competitive advantage to some species over other species.

  At high altitudes in the mountains, the air pressure decreases but oxygen continues to account for about 21 percent of the gases in the air, as it does at sea level. However, there is less oxygen because there is less of all of the air’s gases. For instance, when you go to 3700 meters (12,000 feet) high in the mountains, the air’s pressure is about 40 percent lower than at sea level. This means that you are getting about 40 percent less oxygen.

  If the air pressure is 2 bars, the organisms would have two times (100 percent) as much oxygen at their disposal.

  If the percentage of the oxygen is 26 %, the organisms will receive 5% more oxygen than modern organisms.

  This is to show how important is the density of the atmosphere for delivering oxygen to the species.

  Even if the oxygen level at the end of the Cretaceous was only 15% but the density was 2 bars, the Cretaceous species would have more oxygen at their disposal than the present species.

  Higher oxygen levels, say 28% vs. 21% today, is not enough to explain the ancient species’ gigantism. The air density should have been higher, too.

  For humans, lower air pressureis usually the most significant limiting factor in high mountain regions. The percentage of oxygen in the air at two miles (3.2 km) is about the same as at sea level. However, the air pressure is 30 percent lower at the higher altitude because the atmosphere is less dense. High altitude hypoxia (high altitude sickness) usually begins with the inability to do normal physical activities, distorted vision, headache, fatigue, vomiting, lack of appetite, problems with memorizing and thinking clearly. Pulse rate and blood pressure go up sharply because the hearts pump harder to get more oxygen to the cells. This is very stressful, especially for huge animals.

  People from high mountain regions produce more hemoglobin in their blood and increase their lung expansion capability, in order to get enough oxygen carried by the blood. When animals live in an environment with very high amounts of oxygen we should expect the opposite—lower amounts of hemoglobin, different hemoglobin, and smaller lungs of the animals compared to their bodies.

  In 2009, G. Keller, A. Sahni, and S. Bajpai wrote in their article “Deccan volcanism, the KT mass extinction and dinosaurs,” that “Recent advances in Deccan volcanic studies indicate three volcanic phases with the phase-1 at 67.5 Ma followed by a 2 m.y. period of quiescence. Phase-2 marks the main Deccan volcanic eruptions in Chron 29r near the end of the Maastrichtian and accounts for∼80% of the entire 3500 m thick Deccan lava pile. At least four of the world’s longest lava flows spanning 1000 km across India and out into the Gulf of Bengal mark phase-2.”

  The main eruption phase of the Deccan lava flows, here phase-2, was near the end of the Cretaceous.

  The gargantuan volcanic lava flow into the ocean through the Gulf of Bengal and the volcanic gases acidified the ocean for a prolonged time, probably 100,000 years.

  The acidification of the ocean, prolonged periods of reduced sunlight, and the cooling of the climate because of the cometary cloud disturbed the marine biota and the production of oxygen by ocean phytoplanktons, major oxygen producers.

  The energy amounts available to the Mesozoic animals during the catastrophic events were tremendously reduced because of the huge loss of plant mass and the drop of available oxygen. The ecosystem could no longer sustain such a great number of animals. Especially affected were the huge species, which could not survive the energy deprivation.

  Oxygen decreased in the atmosphere, but also in the waters. Marine waters, fresh waters, or groundwaters were depleted of dissolved oxygen.

  The environmental conditions were the worst during the cometary hits, but the reduced sunlight, the cooler climate, the lower oxygen levels, and the food supply reduction lasted for tens of thousands of years after the impacts.

  Initial symptoms of oxygen deficiency may include fatigue, overall weakness, blood circulation problems, poor digestion, muscle aches and pains, dizziness, memory loss, and irrational behavior. When the immune system is compromised by a lack of oxygen, the body is more susceptible to opportunistic bacteria and fungi, viraland parasitic infections, flu and colds. Reptiles are veryvulnerable to fungal diseases, while mammals are highly resistant to fungal diseases.

  After the impact thevegetation suffered a short but severe crisis. The devastation of forests and other plants after the K-Pg boundary impact was a global phenomenon. Half of the plant species died off during the K comet events a
nd were replaced by other species, which caused additional problems to many animals that were not used to such vegetation.

  Below the boundary there are massive amounts of angiosperm pollen (fine powdery substance produced by the anthers of flowering plants), but the boundary itself and several centimeters above has little or no angiosperm pollen—instead, it is dominated by fern spores. Ferns are the first plants to recolonize devastated lands. Higher plants return later.

  Douglas Nichols and Kirk Johnson wrote in their book Plants and the K-T Boundary, “Tschudy found a modern analogue for this pioneer plant community in description of the volcanic island of Krakatau, Indonesia, which has been essentially wiped clean of vegetation by a cataclysmic explosion in 1883. Richards published an account of the recolonization of Krakatau by plants. The earliest visitors to the caldera found no plants living on it. A botanist arriving in 1886 found that some plants had returned and was impressed that most of them were ferns. After a few years, immigrant species from nearby island evidently reestablished the former, diverse communities.”

  In the heavily stressed environment during the K-Pg catastrophe, the animals needed even more energy from oxygen and food to survive.

  Dinosaurs abruptly lost their metabolic advantages during the catastrophic events because air pressure and oxygen levels dropped, food became scarce, the temperatures dropped, and seasons appeared.

  Cope’s rule, named after the paleontologist Edward Drinker Cope, postulates that population lineages tend to increase in body size over evolutionary time. Large animals find it easier to avoid or fight off predators, to capture prey, or to kill competitors, etc. Although this increases each individual’s fitness, it leaves the species more susceptible to extinction.

  Many researchers assume that there was a lingering impact winter, but, as a matter of fact, there is no need for such a drastic drop of temperatures to cause the mass extinction. The cooling of the climate was not drastic enough to be compared to nuclear winter or impact winter.