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The Marine Environment

Ocea 101. The Marine Environment. Raphael Kudela. Beginnings of the Universe, Earth, and Life The Universe and Solar System Dimensions and distances Our planets Earth’s Composition Structure of the Earth Types of rocks Relative versus Absolute Dating Geological History

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The Marine Environment

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  1. Ocea 101 The Marine Environment Raphael Kudela Beginnings of the Universe, Earth, and Life • The Universe and Solar System • Dimensions and distances • Our planets • Earth’s Composition • Structure of the Earth • Types of rocks • Relative versus Absolute Dating • Geological History • Where did the water and salts come from? • Origins of Life • Cold versus Hot • autotrophic, heterotrophic, chemotrophic

  2. The Universe and Galaxies • Still expanding… • Universe Contains ~1020 stars • Milky Way is about 15 billion years old (byp), and is a Spiral galaxy • Our galaxy contains about 100 billion stars • ~100,000 light years across

  3. Structure of the Early Universe

  4. Turquoise or Beige? • Glazebrook and Baldry (2002) calculated that the universe was Turquoise…. • But it turns out it’s really Beige.

  5. ~ 5 byp old Condensed from a stellar supernova--it started as a hot, rotating cloud of gases The Solar System

  6. The Solar System • As the solar system condensed, it formed planets…those that are close to the sun lost their atmospheres • Proto-Earth formed ~4.8 byp • 100,000x larger, and 500x heavier • Moon formed by an impact with something the size of Mars • Earth is far enough away from the sun to keep its atmosphere, close enough not to freeze

  7. The Earth’s Composition • 3 Layers: • Core (Fe, Ni) • Mantle (Fe, Mg, Si, O) • Crust (aluminosilicates) • 3 Types of Rock: • Igneous • Sedimentary • Metamorphic • Oceanic Basins are formed of basalts, continents are mostly granitic

  8. Dating Rocks • Relative Dating • Early 19th Century • Correlate rock strata with fossils • Absolute Dating • Curies discovered radiation • Almost all rocks have radio-isotopes • If you know t1/2, can calculate exact date

  9. Radioisotope Half-life Radon-222 4 days Strontium-90 28 years Radium-226 1602 years Plutonium-239 24 400 years Uranium-235 700 000 000 years Carbon-14 5730 years Phosphorous-32 14.3 days Tritium (H-3) 12.3 years Americium-241 432 years Nitrogen-13 9.96 minutes

  10. Radioactive Decay Functions Pt=P0 e-lt P= Parent Isotope D= Daughter Isotope t= Time l= Radioactive decay function t1/2= half-life

  11. Geological History • Initially ,there was no atmosphere, no ocean (too hot), no oxygen! • ~4byp, oceans formed • Outgassing of volcanoes, or “snow-balls”? • Water allows chemical weathering of rocks • Heavy elements (Na, Ca, K, Si, Mg, Fe) appear to have come from rocks (dissolution) • Excess volatiles (Cl, S, C, N) had to come from volcanoes!

  12. Hydrologic Cycle

  13. Scientific Hypotheses (post-Beagle) • Edward Forbes--The “azoic hypothesis” • Ross Brothers--Deep sea life at the poles, and the “emergence hypothesis” • Darwin: Natural selection and evolution • 1857: T.H. Huxley describes “Bathybius haeckllii”

  14. Origins of Life • Development of amino andnucleic acids • 1st organisms were probably simply “heterotrophs” ~3.85 byp • ~3.5 byp, first autotrophs, blue-green algae (or cyanobacteria) arose…adapted to an oxygen rich atmosphere

  15. Endosymbiosis Hypothesis First proposed by Lynne Margulis (1974) We are symbionts on a symbiotic planet and if we care to, we will find symbiosis everywhere” -- Lynne Margulis

  16. Evolution of Photosynthesis • Photosynthesis evolved in the absence of oxygen (a very reducing atmosphere) • It evolved independently in a number of bacterial organisms • It is responsible for all present-day oxygen in the atmosphere

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