introduction to oceanography - uclaschauble/epss15_oceanography/... · lecture 14: tides,...

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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

Lecture 14: Tides, Biological Productivity

Introduction to Oceanography 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

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)

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

Caused by gravity and between Earth, Moon & Sun, their orbits around each other, and the Earth’s daily spin

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

•  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

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

•  Earth-Moon Distance –  384,000 km

•  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

To Sun

Brews Ohare, Wikimedia, Public Domain, http://en.wikipedia.org/wiki/File:Earth-

Moon.PNG

Not to scale!

Scaled image of Earth-Moon distance, Nickshanks, Wikimedia Commons, Creative Commons A 2.5

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Phases of the Moon •  New Moon •  Waxing Crescent •  1/2 Moon: First

quarter •  Full Moon •  Etc.

– 7 days/quarter

WAXING CRESCENT

First Quarter

Full Moon

WANING CRESCENTThird Quarter

Tom Ruen, Wikimedia Commons, Public Domain, http://en.wikipedia.org/wiki/

File:Moon_phase_calendar_May2005.png

Phases of the Moon

Figure from NASA Starchild, Public Domain), http://starchild.gsfc.nasa.gov/Images/StarChild/icons/

moon_above.gif

Full New

1st Qtr

3rd Qtr

The Big Picture 3: Bulges

•  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).

Figures from U. Tennessee, http://csep10.phys.utk.edu/astr161/lect/time/tides.html

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

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

NOAA, Public Domain, http://oceanservice.noaa.gov/education/kits/tides/media/tide06a_450.gif

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:

•  Tide generating force falls off faster with radius than gravity!

€

Ftides ∝GMMoon

REarth−Moon

3

3

Equilibrium Theory of the Tides Sun is much more massive!

»  Msun ~ 3x107 Mmoon

BUT Sun is much further away! »  Rsun ~ 400 Rmoon

€

FSFL

≈

GMsRSE3

GMmRmE3

=Ms

Mm

RmE3

RSE3 = 3×107 × 1

4003= 0.47

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

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

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

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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

Thermococcus Gammatolerans, an Archaebacterium, Angels Tapias, Wikimedia Commons, Creative Commons A 3.0 Unported, http://commons.wikimedia.org/wiki/File:Thermococcus_gammatolerans.jpg

Halobacteria (actually Archaea) and Eukarya (Dunaliella salina), San Francisco Bay CA, dro!d, Wikimedia

Commons, Creative Commons A S-A 2.0 http://commons.wikimedia.org/wiki/

File:Salt_ponds_SF_Bay_%28dro!d%29.jpg

Archaea Eukaryota

Copepod, NOAA, Public Domain, http://

www.glerl.noaa.gov/pubs/photogallery/Waterlife/

pages/0737.html

Ostreococcus, a picoplankton (<1x10–6 m across!), Wenche Eikrem

and Jahn Throndsen, University of OsloWikimedia Commons, CC A S-A

2.5, http://en.wikipedia.org/wiki/File:Ostreococcus_RCC143.jpg

Public Domain

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;

are the base of the food chain a. Autotrophs are Primary Producers b. Photosynthesizing plants, algae,

some bacteria (store solar energy) c. Chemosynthetic bacteria

Cyanobacteria, NASA, Public Domain, http://

microbes.arc.nasa.gov/images/content/gallery/lightms/publication/lyngbya.jpg

Sargassum natans (eukarya), James St. John, Creative Commons Attribution 2.0 Generic, https://commons.wikimedia.org/wiki/File:Sargassum_natans_(brown_algae)_(San_Salvador_Island,_Bahamas)_1_(15867880028).jpg

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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/explorations/02sab/logs/aug09/media/

lines.html

Adapted from figure

by Aushulz, Wikimedia Commons,

Creative Commons A

S-A 3.0, http://

commons.wikimedia.org/

wiki/File:Chlorophyll_ab_spe

ctra2.PNG

Photosynthesis Reaction

6CO2 + 6H2O ——> C6H12O6 + 6O2

sunlight

Carbon dioxide

water (yields) Glucose (a sugar)

Oxygen + +

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

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

C6H12O6 + 6O2 ——> 6CO2 + 6H2O

Carbon dioxide

water (yields) Glucose (a sugar) Oxygen + +

+ ENERGY

Questions

Sargassum, photo from South Atlantic Fishery Management Council, http://www.safmc.net/Portals/6/weedline%202.jpg

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How can we measure productivity? -Timed weighing of autotrophs

Good for big land plants, possible for large seaweed.

However, measurements are only local.

Hard to weigh microorganisms, particularly when they have a very short lifecycle.

-Timed “weighing” of inorganic carbonAdd labeled inorganic carbon (14CO2) to ocean water

See how fast organisms convert it to organic molecules

Works well for microorganisms, but still a local measurement.

Color-imetry! (yes, it means what you think) -  Chorophyll enables photosynthesis by absorbing blue and red

light. Green light is reflected or scattered. -  Green ocean implies lots of chlorophyll

-  Lots of chlorophyll implies lots of productivity!

-  Satellites like SEASTAR can measure color from space. This makes colorimetry ideal for global ocean surveys, if it works. This technique will be bad for long-lived plants (chlorophyll is present even when big plants aren’t active, I.e. spruce trees)

How can we measure productivity?

HYPOTHESIS: Green color in the ocean correlates with primary productivity.

PREDICTION: Productivity estimated from color should be the same as productivity measured by “weighing” uptake of inorganic carbon.

Colorimetry compared with “weighing”

From Measured uptake of inorganic 14C

M.J. Behrenfeld & P.G. Falkowski. 1997. Photosynthetic rates derived from satellite-based chlorophyll concentration. Limnol. Oceanogr. 42:1-20

From

Sat

ellit

e C

olor

imet

ry There is good agreement, but also a lot of scatter.�Colorimetry may be a reasonable model, but we still don’t know all the details!

Productivity from SeaWiFS

SeaWiFS/NASA/Rutgers University, Public Domain http://marine.rutgers.edu./opp/swf/Production/gif_files/PP_9809_9908.gif

Figure from University of Michigan, http://www.globalchange.umich.edu/

globalchange1/current/lectures/kling/energyflow/typeeco2.gif

Primary Production 1.  Amount depends on:

a.  Driving Energy (Solar or chemical) b.  Nutrients

2.  Regions of Highest Productivity a.  Continental margins: Upwelling (Ekman

pumping) and vertical mixing common along margins. Also close to rivers, dust sources

b.  Equatorial Divergences c.  Antarctic Divergence d.  Northern Pacific & Northern Atlantic

i. Deepwater upwelling in Pacific; Divergence within subpolar Arctic/Atlantic gyres

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Primary Production 3. Regions of Lowest Productivity

a. Interiors of subtropical gyres i. This is where ocean water is most stably

stratified --- Strong, stable pycnocline, little vertical

mixing. Few nutrients are brought up to the surface.

--- These are the “deserts” of the ocean, most nutrients lost as dead organisms sink into the deep ocean

Primary Production 4.  Primary Producers (Autrotrophs)

a.  Eukaryotic Algae (Seaweeds & Single celled photosynthesizers)

i.  Benthic (coastal): minor component i.  Seaweeds

ii.  Pelagic phytoplankton: primary component i.  Diatoms, dinoflagellates, coccolithophores, etc.

b.  Cyanobacteria: blue-green algae c.  Picoplankton / Archea(?) d.  Chemosynthetic Bacteria: Use inorganic

compounds to get energy i.  They oxidize compounds such as H2S (Hydrogen

sulfide)

Questions

Abalone, Oregon Coast Aquarium, photo by Little Mountain 5,

Wikimedia Commons, Creative Commons A S-A 3.0, http://

commons.wikimedia.org/wiki/File:Abalone_OCA.jpg

HABITAT

NOAA, Public Domain, http://oceanexplorer.noaa.gov/explorations/04deepscope/background/deeplight/media/diagram3_600.jpg

Ocean Habitats

•  Where do organisms live in the oceans? – Biozones

•  Benthic vs. Pelagic –  Sea floor vs. Free-floating/free-swimming

– Light Zones •  Photic, Dysphotic, Aphotic

Habitat

1. Pelagic (oceanic): live in the water column

2. Benthic: Live in or on ocean bottom Whale shark, Georgia aquarium, Zac Wolf, Creative Commons A S-A 2.5, http://commons.wikimedia.org/wiki/File:Whale-shark-enhanced.jpg

Coral polyp, Nick Hobgood, Creative Commons A S-A 3.0, http://commons.wikimedia.org/wiki/

File:Euphyllia_glabrescens_%28Hard_coral%29_with_polyps_extended.jpg

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Ocean Habitats

• Neritic vs. Oceanic– Shelf waters vs. deep waters– Neritic/Sublittoral: photic zone reaches to sea floor

Figure by Chris_huh, Wikimedia Commons, Creative Commons A S-A 3.0, http://en.wikipedia.org/wiki/File:Oceanic_divisions.svg

Relative Habitat Sizes

•  Abyssal pelagic: 54% oceans by volume •  Abyssal: 75% sea floor by area

•  Yet most of the bioproduction occurs elsewhere, near the surface

Questions

Spotted garden eel, photo by Nick Hobgood, Wikimedia Commons, Creative Commons A S-

A 3.0, http://commons.wikimedia.org/wiki/File:Heteroconger_hassi_%28Spotted_garden_

eel%29.jpg

Zonation by Lighting

•  Photic Zone: lit by sunlight, ~ 100 - 500m deep – Euphotic Zone: autotrophs capture more

energy than they use; net fixation of carbon; net production of O2

– Dysphotic Zone: Not enough light for profitable photosynthesis

•  Aphotic Zone: Permanent darkness

Ope

n O

cean

NOAA, Public Domain, http://oceanexplorer.noaa.gov/explorations/04deepscope/background/deeplight/media/diagram3_600.jpg

Coastal Ocean

NOAA, Public Domain, http://oceanexplorer.noaa.gov/explorations/04deepscope/background/deeplight/media/diagram3_600.jpg