Introduction to Oceanography Lecture 14: Tides, Biological Productivity Bay of Fundy -- low tide, Photo by Dylan Kereluk, . Creative Commons A 2.0 Generic, http://commons.wikimedia.org/wiki/File:Bay_of_Fundy_-_Tide_Out.jpg Introduction to Oceanography Memorial Day holiday Monday no lab meetings Go to any other lab section this week (and let the TA know!) Mudskipper (Periophthalmus modestus) at low tide, photo by OpenCage, Wikimedia Commons, Creative Commons A S-A 2.5, http://commons.wikimedia.org/wiki/File:Periophthalmus_modestus.jpg 1 Tides Planet-length waves Cyclic, repeating rise & fall of sea level – Most regular phenomenon in the oceans Daily tidal variation has great effects on life in & around the ocean (Lab 8) Caused by gravity and between Earth, Moon & Sun, their orbits around each other, and the Earth’s daily spin Photos by Samuel Wantman, Creative Commons A S-A 3.0, http://en.wikipedia.org/ wiki/File:Bay_of_Fundy_Low_Tide.jpg and http://en.wikipedia.org/wiki/ File:Bay_of_Fundy_High_Tide.jpg Earth-Moon-Sun System • Earth-Sun Distance 150,000,000 km • Earth-Moon Distance 385,000 km Much closer to Earth, but much less massive • Earth Obliquity = 23.5 degrees – Seasons Figure by Homonculus 2/Geologician, Wikimedia Commons, Creative Commons A 3.0, http://en.wikipedia.org/wiki/ File:Lunar_perturbation.jpg 2 Tides are caused by the gravity of the Moon and Sun acting on Earth and its ocean. Pluto-Charon mutual orbit, Zhatt, Wikimedia Commons, Public Domain, http:// en.wikipedia.org/ wiki/File:Orbit2.gif Newton’s cannon, Wikimedia Commons, Creative Commons A S-A 3.0, http://en.wikipedia.org/wiki/File:Newton_Cannon.svg • Basic Orbital Mechanics • Planetary objects stay in orbit due to balance of Gravity and Centrifugal forces (at their center of mass) • Like a weight spun on the end of string Scaled image of Earth-Moon distance, Nickshanks, Wikimedia Commons, Creative Commons A 2.5 To Sun Not to scale! • Earth-Moon Distance Brews Ohare, Wikimedia, Public Domain, http://en.wikipedia.org/wiki/File:Earth- – 384,000 km Moon.PNG • Revolution period of the Moon – 27.3 Days • Rotation period of the Moon also 27.3 Days • Synchronous Rotation: We always see the same side of the Moon 3 Phases of the Moon • New Moon • Waxing Crescent • 1/2 Moon: First quarter WAXING CRESCENT • Full Moon First • Etc. Quarter – 7 days/quarter Full Moon Third Quarter WANING CRESCENT Tom Ruen, Wikimedia Commons, Public Domain, http://en.wikipedia.org/wiki/ File:Moon_phase_calendar_ May2005.png Phases of the Moon 1st Qtr Full New 3rd Qtr Figure from NASA Starchild, Public Domain), http://starchild.gsfc.nasa.gov/Images/StarChild/icons/ moon_above.gif 4 The Big Picture 3: Bulges Figures from U. Tennessee, http://csep10.phys.utk.edu/astr161/lect/time/tides.html • Moon’s gravitational force acting on the Earth tugs out a tidal bulge towards moon • Centrifugal force pushes a bulge away from moon on the far side of the Earth – TIDES TRY TO TRACK THE MOON The Sun’s gravity has a similar, but smaller effect (1/2 as strong). Andrew Buck, Wikimedia Commons, Creative Commons A S-A 3.0, http:// commons.wikimedia.org/wiki/File:Tidal_braking.svg The Moon and Sun both influence tides NOAA, Public Domain, http://oceanservice.noaa.gov/education/kits/tides/media/tide06a_450.gif Constructive interference: Sun and Moon tidal bulges oriented the same way, resulting in strong tides – Spring Tide Destructive interference: Sun and Moon tidal bulges partially cancel each other, resulting in weak tides – Neap Tide 5 Effect of Sun & Moon Together • Spring Tides & Neap Tides Adapted from figure by Nicky McLean, Wikimedia Commons, Public Domain, http://en.wikipedia.org/wiki/ File:Tide.Bridgeport.30d.png Why is the moon’s effect on the tide greater than the sun’s? • Gravity balances Centrifugal at Earth’s center of mass • Elsewhere they don’t cancel – TIDE GENERATING FORCE: GMMoon Ftides ∝ 3 REarth− Moon • Tide generating force falls off faster with radius than gravity! € 6 Equilibrium Theory of the Tides Sun is much more massive! 7 » Msun ~ 3x10 Mmoon BUT Sun is much further away! » Rsun ~ 400 Rmoon GMs 3 3 FS RSE Ms RmE 7 1 ≈ = 3 = 3×10 × 3 = 0.47 F GMm M R 400 L 3 m SE RmE Solar tide 1/2 as big as lunar tide € Tides in narrow, tapering bays • In narrow bays attached to the ocean, tides can slosh straight in and out • Large tides can occur when the tidal frequency matches natural (resonant) oscillations of the bay Image from NOAA Online School for Weather, Public Domain, http:// www.srh.noaa.gov/ jetstream/ocean/ fundy_max.htm 7 Bay of Fundy tides QUESTIONS? Mont Saint-Michel and Tombelaine (tidal islands), France, Uwe Küchler, Wikimedia Commons, CC A S-A 3.0, http://commons.wikimedia.org/wiki/File:Mont_st_michel_aerial.jpg 8 Marine Life & Biological Productivity Estimated marine chlorophyll & terrestrial vegetation coverage map 1997-1998, SeaWiFS/NASA, Public Domain, http://en.wikipedia.org/wiki/File:Seawifs_global_biosphere.jpg CLASSIFICATION SCHEMES FOR MARINE ORGANISMS 1. Taxonomy: Based on genealogical relationships between organisms (ie, felines) 2. Mode of Nutrition 3. Habitat 4. Mobility 9 Genetic classification: Three Domains of Life 1. Bacteria: Simple single celled organisms, lack nucleus (E. coli) 2. Archaea: Outwardly similar to Bacteria; many live in extreme environments (hot springs, nuclear reactors, saline lakes, etc.) 3. Eucarya: Have a membrane-enclosed nucleus and other organelles; include protists, animals, fungi, plants Whole genome tree of life, diagram by User_A1, based on Ciccarelli (2006) and Letunic (2007), Public Domain. http:// en.wikipedia.org/wiki/ File:CollapsedtreeLabels- simplified.svg Bacteria Cyanobacterial colonies, left: NASA, Public Domain, http://microbes.arc.nasa.gov/images/content/gallery/lightms/ publication/lyngbya.jpg; right: Hamelin Pool -- Shark’s Bay, Australia, photo by Happy Little Nomad, Wikimedia commons, CC A S-A 2.0, http://en.wikipedia.org/wiki/File:Stromatolites_in_Shark_Bay.jpg 10 Archaea Thermococcus Gammatolerans, an Archaebacterium, Halobacteria (actually Archaea) and Eukarya (Dunaliella Angels Tapias, Wikimedia Commons, Creative salina), San Francisco Bay CA, dro!d, Wikimedia Commons A 3.0 Unported, http:// Commons, Creative Commons A S-A 2.0 http:// commons.wikimedia.org/wiki/ commons.wikimedia.org/wiki/ File:Thermococcus_gammatolerans.jpg File:Salt_ponds_SF_Bay_%28dro!d%29.jpg Eukaryota Ostreococcus, a picoplankton (<1x10–6 m across!), Wenche Eikrem and Jahn Throndsen, University of Copepod, NOAA, Public OsloWikimedia Commons, CC A S-A Domain, http:// 2.5, http://en.wikipedia.org/wiki/ www.glerl.noaa.gov/pubs/ File:Ostreococcus_RCC143.jpg photogallery/Waterlife/ pages/0737.html Public Domain 11 Questions? Comb jelly(?) (Eukaryota), Nick Hobgood, Wikimedia Commons, Creative Commons A S-A 3.0, http://commons.wikimedia.org/wiki/File:Combjelly.jpg What does it eat? 1. Autotrophs: Make their own food; Cyanobacteria, NASA, Public are the base of the food chain Domain, http:// microbes.arc.nasa.gov/images/ content/gallery/lightms/ a. Autotrophs are Primary Producers publication/lyngbya.jpg b. Photosynthesizing plants, algae, some bacteria (store solar energy) c. Chemosynthetic bacteria Sargassum natans (eukarya), James St. John, Creative Commons Attribution 2.0 Generic, https:// commons.wikimedia.org/wiki/ File:Sargassum_natans_(brown_algae)_(San_Salvador_Is land,_Bahamas)_1_(15867880028).jpg 12 What does it eat? 1. Heterotrophs: cannot make their own food; must eat other organisms or their remains a. Herbivores: eat plants b. Carnivores: eat animals c. Omnivores: eat plants & animals d. Bacteria: many decompose dead organic matter (E. coli) Barracuda are heterotrophs, NOAA, Public Domain, http://www.photolib.noaa.gov/htmls/ reef2567.htm So are yeast, Masur, Wikimedia Commons, Creative Commons A S-A 2.5, http://en.wikipedia.org/wiki/ File:S_cerevisiae_under_DIC_microscopy.jpg Photosynthesis Living systems require chemical energy Chlorophyll: a green pigment that captures photons and transfers their energy to electrons, an through a series of steps creates carbohydrate molecules (chemical energy) and oxygen. Chlorophyll looks green because it absorbs red and blue light, and reflects green light Sargassum algae, NOAA, Public Domain, http://oceanexplorer.noaa.gov/ Adapted explorations/02sab/logs/aug09/media/ from figure lines.html by Aushulz, Wikimedia Commons, Creative Commons A S-A 3.0, http:// commons.wi kimedia.org/ wiki/ File:Chlorop hyll_ab_spe ctra2.PNG 13 Photosynthesis Reaction sunlight 6CO2 + 6H2O ——> C6H12O6 + 6O2 Carbon + water (yields) Glucose + Oxygen dioxide (a sugar) Typically, ~100 grams carbon/ year / meter2 is fixed to sugar in the open ocean PRIMARY PRODUCTION • Amount of inorganic carbon (mainly CO2) “fixed” by autotrophic organisms into organic compounds – Based on reactions harnessing solar or chemical energy 14 Respiration • Respiration: opposite reaction of photosynthesis • Dis-assembly of carbohydrate (food) molecules in the presence of oxygen to release chemical energy • The main byproducts of respiration are H2O and CO2. These are released to the environment • Both plants & animals use respiration • Some bacteria & archea also respire + ENERGY C6H12O6 + 6O2 ——> 6CO2 + 6H2O Glucose + Carbon (a sugar) Oxygen (yields) + water dioxide Questions Sargassum, photo from South Atlantic Fishery Management Council, http://www.safmc.net/Portals/6/weedline%202.jpg 15 How can we measure productivity? -Timed weighing of autotrophs Good for big land plants, possible for large seaweed. However, measurements are