Influence of abiotic factors on the evolution of marine biota during the Phanerozoic

Mass extinctions were caused by powerful volcanism, asteroid impacts and, probably, changes in the frequency of geomagnetic inversions. These factors acted within close time intervals. This gives reason to believe that they are coherent, interconnected, by a common root cause of a higher order, located outside the solar system.

Ideas about the geomagnetic field's influence on evolution and biodiversity are controversial. The quantitative distribution of datum levels of oceanic microplankton during the last 2.0 Ma shows a correlation with geomagnetic reversals. A decrease in field intensity increases cosmic irradiation of the Earth's surface, which can activate mutagenesis leading to the emergence of new species. Moreover, since the correlation of the geomagnetic field intensity with the composition of the atmosphere, temperature, climate, volcanism, and other environmental conditions was revealed, it is possible to assume its influence on evolutionary processes as part of the overall complex of environmental conditions. Geomagnetic polarity superchrons ended with mantle plume formation, which produced trap eruptions and initiated Phanerozoic mass faunal extinctions. The sources of the geomagnetic field and plume formation leading to trap volcanism are at the boundaries of the Earth's inner spheres, which explains their correlation. And their correlation with impact events as one of the causes of extinction can be explained by a cosmic primary cause that lies beyond the confines of the solar system.

The influence of changes in the geomagnetic field on the evolution of organisms is multifaceted. Lowering of the field strength increases cosmic irradiation of the Earth's surface, which can activate mutagenesis leading to speciation. Since the correlation of the geomagnetic field intensity with the composition of the atmosphere, temperature, climate, volcanism and other environmental conditions is revealed, its effect on the evolutionary processes within the general complex of influencing factors is assumed. The source of the geomagnetic field is at the core-mantle boundary, i.e. in the same area where sources of plume formation and, accordingly, of volcanism are located. The activation of impact events in close time intervals can be explained by the influence of the same factors external to the solar system, such as the galactic tidal forces or the fluxes of dark matter when the solar system crosses the plane of the Milky Way. Mass extinctions are caused by the combined effects of volcanism, impact events and geomagnetic changes.

The micropaleontological study (radiolarians and foraminifera) of the sediment core AMK-340, Reykjanes Ridge, North Atlantic, combined with the radiocarbon dating and Oxygen/Carbon isotopic record, provided data for the reconstruction of the summer paleotemperature on the water depth of 100 m, and paleoenvironments during the Termination I in the age interval of 14.5–8 ka. The response of the main microfossil species on the paleoceanographic changes within the Bølling-Allerød (BA) warming, the Younger Dryas (YD) cold event, and final transition to the warm Holocene was different. The BA warming was well reflected in the radiolarian and benthic but not planktic foraminiferal record. The high abundances of the cold-water radiolarian species Amphimelissa setosa as the Greenland/Iceland Sea indicator marked a cooling at the end of the BA and within the start of the YD at 13.2–12.3 ka. The micropaleontological and isotopic data together with the paleotemperature estimates for the Reykjanes Ridge at 60° N document that, after the warm BA, the middle YD ca. 12.5–12.2 ka was the next significant step toward the Holocene warming. Start of the Holocene interglacial conditions was reflected in abundant occurrence of the microfossils being indicators of the open boreal North Atlantic environments and lower oxygen isotope values indicating increasing warmth.

Earthly life arose and developed in the environment of the geomagnetic field, which shields the Earth from the "solar wind" and preserves the atmosphere. The geomagnetic field is continuously changing. Its tension fluctuates, the poles move, sometimes up to a complete reversal of polarity (inversions). With the weakening of the field tension, it is possible to amplify the Earth's irradiation with cosmic rays, which can cause genetic mutations. The relationship between evolutionary changes in ocean microplankton and geomagnetic inversions is shown for 2 million years. Changes in the geomagnetic field are elements of a complex system of environmental changes (volcanism, climate, consequences of impact events, etc.), which lead to extinctions and stimulate evolution. Земная жизнь возникла и развивалась в среде геомагнитного поля, которое экранирует Землю от «солнечного ветра» и сохраняет атмосферу. Геомагнитное поле непрерывно изме-няется. Колеблется его напряженность, полюса перемещаются, иногда вплоть до полной смены полярности (инверсии). При ослаблении напряженности поля возможно усиление об-лучения Земли космическими лучами, что может вызывать генетические мутации. Показана связь эволюционных изменений океанского микропланктона с геомагнитными инверсиями в течение 2 млн лет. Изменения геомагнитного поля являются элементами сложной системы изменений среды (вулканизма, климата, последствий импакт-событий и др.), которые приво-дят к вымираниям и стимулируют эволюцию

In the interval of the Triassic–Jurassic boundary up to 80% of marine species became extinct. Themain hypotheses on the causes of this mass extinction are reviewed. The extinction was triggered by a power�ful eruption of basalts in the Central Atlantic Magmatic Province. In addition, several impact craters havebeen found. Extraterrestrial factors resulted in two main sequences of events: terrestrial, leading to strong vol�canism, and extraterrestrial (impact events). They produced similar effects: emissions of harmful chemicalcompounds and aerosols. Consequences included the greenhouse effect, darkening of the atmosphere (whichprevented photosynthesis), stagnation of the oceans, and anoxia. Biological productivity decreased; foodchains collapsed. As a result, all vital processes were disturbed, and a large portion of the biota went extinct.

Paleozoic apocalypse: what causes? Barash M.S. P.P. Shirshov Institute of Oceanology, Russian Academy of Sciences, Pr. Nakhimovskii, 36, Moscow, 117997, Russia barashms@yandex.ru On the Paleozoic-Mesozoic boundary, 251.0±0.4 Ma, there was the largest in history of the Earth mass extinction of organisms. The end-Permian mass extinction eliminated 96% of all marine species and had a significant impact on land species as well. Marine species biodiversity was reduced from ~250 thousand species to less than 10 thousand. What were the causes of this catastrophe, which has received the name a Paleozoic Apocalypse? As the causes of biota extinction many factors are offered: disappearance of ecological niches during connection of continental plates in Pangaea; hypersalinity; an anoxia; increased CO2; poisoning by H2S; sea level lowering; transgressions; volcanism; warming and acid rains as a result of volcanism; warming owing to methane discharge from gas-hydrates; short-term cold episodes; impact events, i.e. collisions with large asteroids or a combination of these mechanisms. All these factors which have reduced a biodiversity are proved by paleontological, geological, geochemical, isotope, and other data. It is very important to note, that some of these factors are in hierarchical relations, but others affected independently, and in limited time interval. On changes of systems of a terrestrial surface, including biosphere, the changes occurred in internal geospheres influenced. Connection of a biodiversity with tectonics, geoid evolution, mantle convection, and the shifts of the Earth core caused changes of geopolarity is supposed. Causal relationships were carried out through volcanism, fluctuations of a sea level, methane discharge from gas-hydrates, strengthening of ocean stratification, and an anoxia. Сorrelation of extinctions with volcanic eruptions is precisely revealed. Temporary correlations between the largest eruptions of Siberian traps, and the extinction are tracked. Eruptions caused «the volcanic winter» with a global cold episodes because of aerosol shielding of atmosphere, outflow of harmful gases and the acid rains. After the main basalt outflow «the volcanic summer» followed, detaining restoration of a biodiversity and strengthening stratification of ocean. Decomposition of gas-hydrates conducted to outflow of huge amounts of CO2 and to occurrence of very strong greenhouse effect. Fast global warming caused changes of environment harmful to biosphere: weakening of upwellings, stagnation of ocean, falling of bioproductivity. Influence of volcanism of the Siberian trap province was very powerful. All the listed factors developed rather slowly and could not cause fast biotic catastrophe. Fossils distribution in sections of China has shown that extinction occurred during 3 Ma, however the most intensive (in an interval less than 500 years) it was 251.4 Ma (Jin et al., 2000). The trigger of sharp changes on a background of gradually developing harmful ecological conditions were, possibly, impacts of large asteroids as it was on Cretaceous/Paleogene boundary (Barash, 2008). Influence of impact events is proved only last years. Crater Bedout (diameter 180-200 km) is found near Australia (Becker et al., 2006). Crater Araguainha (40 km diameter) is found in Brazil (Lana, Marangoni, 2009). Crater Arganaty in Kazakhstan (315 m diameter) is proved. Some probable impact structures demanding additional researches are found. Possibly, the largest impact event in history of the Earth was impact event in Antarctica, on Wilkes Land (Von Frese et al. 2006). Geophysical methods reveal here a 500-kilometer crater which is settling under the East-Antarctic glacial sheet. Its probable age is 250 Ma. Consequences of asteroid impacts are similar to consequences of volcanism. They caused global distribution of a dust, downturn of light exposure, change of temperature, acid rains, fires, etc. The analysis of the materials available leads to one of the most important inferences that all the terrestrial processes, the biospheric included, develop in close and continuous relation with the extraterrestrial processes that occur beyond the solar system in the space to which our planet belongs (crossing by the Sun of spiral galactic sleeves, its fluctuations perpendicularly to galactic plane or others). References Barash M. S. Evolution of the Mesozoic Oceanic Biota: Response to Abiotic Factors // Oceanology. 2008. Vol. 48. No. 4. P. 538–553. Becker L., Poreda R.J., Basu A.R. et al. Bedout: A Possible End-Permian Impact Crater Offshore of Northwestern Australia // Science. 2004. V. 304. No. 5676. P. 1469-1476. Catalogue of the Earth's Impact structures. Siberian Center for Global Catastrophes, Rus. Acad. of Sciences, Siberian division. Retrieved 2009-08-12. http://omzg.sscc.ru/impact/index1.html Isozaki Y. Integrated ''plume winter" scenario for the double-phased extinction during the Paleozoic-Mesozoic transition: The G-LB and P-TB events from a Panthalassan perspective // Jour. Asian Earth Sc. 2009. V. 36. P. 459-480. Jin Y.G., Wang Y., Wang W. et al. Pattern of Marine Mass Extinction near the Permian-Triassic Boundary in South China // Science. 2000. V. 289. P. 432–436. Lana C., Marangoni Y. The Araguainha impact: a South American Permo–Triassic catastrophic event // Geology Today. 2009. V. 25. No. 1. P. 21-28. Von Frese R.R, Potts L., Wells S. et al. "Permian-Triassic mascon in Antarctica". Eos Trans. AGU, Jt. Assem. Suppl. 2006. V. 87 (36): Abstract T41A-08.

During the Late Devonian extinction, 70–82% of all marine species disappeared. The main causes of this mass extinction include tectonic activity, climate and sea-level fluctuations, volcanism, and the collision of the Earth with cosmic bodies (impact events). The major causes are considered to be volcanism accompanying formation of the Viluy traps and, probably, basaltic magmatism in the Southern Urals, alkaline magmatism within the East European platform, and volcanism in northern Iran and northern and southern China. Several large impact craters of Late Devonian age have been documented in different parts of the world. The available data indicate that this time period on the Earth was marked by two major sequences of events: terrestrial events that resulted in extensive volcanism and cosmic (or impact) events. They produced similar effects such as emissions of harmful chemical compounds and aerosols to cause greenhouse warming and the darkening of the atmosphere, which prevented photosynthesis and cause ocean stagnation and anoxia. This disrupted the food chain and reduced ecosystem productivity. As a result, all vital processes were disturbed and a large part of the marine biota became extinct.

Changes in the geomagnetic field are elements of a complex system of all environmental changes (volcanism, climate, consequences of Impact events, etc.), which lead to extinctions and stimulate evolution. The cause of geomagnetic changes is probably the excitation of mantle activity. Mantle plumes through a long time appear on the surface of the Earth in the form of volcanic activity, changes in the atmosphere, hydrosphere and lithosphere. In the same time interval the impact events become more frequent.

Abiotic events (volcanism, climatic changes, sea level fluctuations, asteroid impacts, etc.) are discussed as causes of the mass extinction. The presence in intervals of sharp changes in biota’s development of several abiotic events, the cause-effect relation between which is unknown or expressly absent, gives us grounds to believe that large-scale changes are affected by more general cosmic factors that are outside the limits of the solar system

An analysis of the biota development in response to the changing abiotic factors shows that long relatively stable periods of transgression, high-energy hydrodynamics, and diverse ecological niches are favorable for a growth of biodiversity and the abundance of organisms. Biota reduction is determined by sharp environmental changes, particularly by multiple alteration of opposite development trends (transgression-regression, warming-cooling, and others). In addition, events harmful for the development of organisms such as global anoxia in the oceans, powerful eruptions of trap basalts and volcanism, and collision of the earth with extraterrestrial bodies negatively influence the biota evolution. The impact of different factors is particularly notable during biotic crises. The abiotic factors influencing the biota development are determined by three fundamental causes: terrestrial, orbital, and extraterrestrial. Frequently, these causes and relevant factors were synchronous or almost synchronous in terms of geological time. Inasmuch as there is no cause-effect relationship between them, we can assume that large-scale environmental changes are determined by general extraterrestrial factors originating beyond the solar system.

Рассмотрение развития биоты в связи с изменениями абиотических факторов показывает, что дпитель­ ные интервалы без резких изменений среды, в условиях трансгрессии, активной гидродинамики и разнообра­зия экологических ниш способствуют увеличению биоразнообразия и количества организмов. Сокращение биоты вызывается быстрым изменением условий, особенно многократной сменой противоположных тенден­ций (трансгрессия - регрессия, потепление - похолодание и др.). Кроме того, отрицательное влияние оказы­ вают однозначно вредные для развития организмов события, такие как глобальное развитие аноксии в океа­нах, мощные излияния трапповых базальтов и вулканизм, столкновение Земли с космическими телами. Особенно ярко выявляется воздействие различных факторов во время биотических кризисов. Абиотические факторы развития биоты определяются тремя фундаментальными причинами - земными (тектоникой, вулка­низмом), орбитальными и космическими. Во многих случаях эти причины и определяемые ими факторы действовали одновременно или близко в геологическом масштабе времени. Поскольку причинно-следственная связь между ними определенно отсутствует, можно полагать, что на крупномасштабные изменения природной среды Земли влияют более общие космические факторы, находящиеся вне пределов Солнечной системы.

An analysis of the biota evolution during the Mesozoic in response to abiotic factors shows that the most important among them are the climate, sea-level position, dynamics and structure of the water column, its chemistry, volcanism, tectonics (horizontal and vertical movements of lithospheric blocks), and collision of the earth with astronomical bodies (impact events). Stable conditions and a variety of ecological niches promoted the growth in the biodiversity. Their changes that resulted in mass extinctions of organisms stimulated evolution. The analysis of the materials available leads to one of the most important inferences that all the terrestrial processes, the biospheric included, develop in close and continuous relation with the extraterrestrial processes that occur beyond the solar system in the space to which our planet belongs.