The Marine Environment Ocea 101 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

Still expanding… Universe Contains ~10 20 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 The Universe and Galaxies

Structure of the Early Universe

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

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

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 The Earth’s Composition

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  1/2, can calculate exact date

RadioisotopeHalf-life Radon days Strontium-9028 years Radium years Plutonium years Uranium years Carbon years Phosphorous days Tritium (H-3)12.3 years Americium years Nitrogen minutes

Radioactive Decay Functions P t =P 0 e - t P= Parent Isotope D= Daughter Isotope t= Time = Radioactive decay function t 1/2 = half-life

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!

Hydrologic Cycle

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”

Origins of Life Development of amino and nucleic 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

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

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