Primary%20Productivity%20in%20the%20Marine%20Environment

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Primary Productivity in the Marine Environment
Fig. 13.5
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Primary productivity

• Energy is converted into organic matter to be
  used by cells
• Photosynthesis using solar radiation
• 99.9 of marine life relies directly or
  indirectly on photosynthesis for food
• Chemosynthesis using chemical reactions
• Happens in hydrothermal vents at bottom of ocean
  with no light

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• Remember, energy cannot be created or destroyed
  it only changes form

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Lets talk about energy

• Biological organisms need biochemical processes
  to happen in an orderly fashion in order to
  maintain life
• Needs constant input of energy to maintain that
  order
• Our cells need energy in form of ATP
• ATP formed during cellular respiration
• Need input of carbon (i.e. glucose) and oxygen
  for cellular respiration
• That carbon source and oxygen comes from
  photosynthesis (primary productivity)

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Photosynthetic productivity

• Chemical reaction that stores solar energy in
  organic molecules
• Photosynthetic organisms fix carbon and energy
  from atmosphere
• Also incorporate other elements and molecules
  necessary for life (nitrogen, phosphorus, etc)
• What do we need these for? For making proteins,
  lipids, DNA, etc.
• Use some of that for their own energy source for
  life
• Excess moves its way up the food chain

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• Now we are going to revisit photosynthesis and
  cellular respiration
• Remember, we are following electrons and protons
• OIL RIG Oxidize it loses, reduced it gains

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• Photosynthesis process of fixing carbon from
  the atmosphere into organic material that now has
  energy from the sun trapped in the bonds of the
  molecule
• What is the chemical formula for photosynthesis?
• Review this Prezi http//prezi.com/2byn9gmriian/p
  hotosynthesis/?utm_campaignshareutm_mediumcopy

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• Cellular Respiration
• Review this Prezi http//prezi.com/8_qehzkw-vuk/c
  ellular-respiration/?utm_campaignshareutm_medium
  copy

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• Is glucose the only molecule that can be broken
  down and oxidized during cellular respiration to
  gain energy?

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Measuring primary productivity

• Capture plankton
• Plankton nets
• Ocean color
• Chlorophyll colors seawater
• SeaWiFs on satellite

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Factors affecting primary productivity

• Nutrients
• Nitrate, phosphorous, iron, silica
• Needed for bacteria and phytoplankton to make
  more DNA, proteins, etc to make more of
  themselves
• Most from river runoff
• Productivity high along continental margins
  because of nutrient runoff
• Solar radiation
• Uppermost surface seawater and shallow seafloor
  are most productive, need light!
• Euphotic zone surface to about 100 m (330 ft)

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Upwelling and nutrient supply

• Cooler, deeper seawater nutrient-rich
• Areas of coastal upwelling sites of high
  productivity

Fig. 13.6a
http//cordellbank.noaa.gov/images/environment/upw
elling_470.jpg
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Light transmission

• Visible light of the electromagnetic spectrum
• Blue wavelengths penetrate deepest
• Longer wavelengths (red, orange) absorbed first

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Light transmission in ocean

• Color of ocean ranges from deep blue to
  yellow-green
• Factors
• Water depth
• Turbidity from runoff
• Photosynthetic pigment (chlorophyll)
• dirty water in coastal areas, lagoons, etc. are
  areas of high productivity, lots of plankton
  (preventing that blue color)

http//upload.wikimedia.org/wikipedia/commons/a/a5
/LightningVolt_Deep_Blue_Sea.jpg
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Types of photosynthetic marine organisms

• Angiosperms
• Seed-bearing flowering plants, example is
  mangroves
• Macroscopic (large) algae
• Larger seaweeds, like kelp
• Microscopic (small) algae
• phytoplankton
• Photosynthetic bacteria

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Macroscopic algae Seaweeds

• Brown algae

http//www.starfish.ch/photos/plants-Pflanzen/Sarg
assum.jpg
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Macroscopic algae Seaweeds

• Green algae

Caulerpa brachypus, an invasive species in the
Indian River Lagoon
Codium
http//www.sms.si.edu/IRLspec/images/cbrachypus2.j
pg
http//192.107.66.195/Buoy/System_Description_Codi
um_Fragile.jpg
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Macroscopic algae Seaweeds

• Red algae
• Most abundant and most widespread of seaweeds
• Varied colors

http//www.agen.ufl.edu/chyn/age2062/lect/lect_15
/22_14B.GIF
http//www.dnrec.state.de.us/MacroAlgae/informatio
n/Indentifying.shtml
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Microscopic algae
http//biologi.uio.no/akv/forskning/mbot/images

• Produce food for 99 of marine animals
• Most are planktonic - phytoplankton
• Golden algae
• Diatoms (tests of silica)
• Most abundant single-celled algae 5600 spp.
• Silicate skeletons pillbox or rod-shaped ? ooze
• Some w/ sticky threads, spines ? slows sinking

www.bren.ucsb.edu/ facilities/MEIAF
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Microscopic algae

• Coccolithophores (plates of ate)
• Flagellated
• calcium carbon plates ? possibly sunshades
• Coccolithid ooze ? fossilized in white cliffs of
  Dover

http//www.esa.int/images
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Microscopic algae

• Dinoflagellates
• Mostly autotrophic some heterotrophic or both
• Flagella in grooves for locomotion
• Many bioluminescent
• Often toxic when toxin is concentrated due to
  bloom
• Red tides (algal blooms) ? fish kills (increase
  nutrients, runoff)

http//www.hku.hk/ecology/porcupine/por24gif/Karen
ia-digitata.jpg
http//oceanworld.tamu.edu/students/fisheries/imag
es/red_tide_bloom_1.jpg
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Microscopic algae

• Dinoflagellates
• Pfiesteria found in temperate coastal waters
• Ciguatera - illness caused from eating fish
  coated with Gambierdiscus toxicus
• Paralytic, diarhetic, amnesic shellfish poisoning

Pfiesteria
http//www.odu.edu/sci/biology/pfiesteria
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Photosynthetic bacteria

• Cyanobacteria many different species
• Extremely small
• May be responsible for half of total
  photosynthetic biomass in oceans

Gleocapsa
Anabaena
http//silicasecchidisk.conncoll.edu/Pics/Other20
Algae/Blue_Green20jpegs/Gloeocapsa_Key45.jpg
http//www.micrographia.com/specbiol/bacteri/bacte
r/bact0200/anabae03.jpg
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Regional primary productivity

• Varies from very low to very high depending on
• Distribution of nutrients
• Seasonal changes in solar radiation
• About 90 of surface biomass decomposed in
  surface ocean
• About 10 sinks to deeper ocean
• Only 1 organic matter not decomposed in deep
  ocean ? reaches bottom
• Biological pump (CO2 and nutrients to sea floor
  sediments)

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Temperate ocean productivity

• Seasonal variation with temperature/light/nutrient
  s
• Winter
• High winter winds ? mixing of sediments/plankton
• Low light few phytoplankton ? nutrients
  increase
• Spring
• Phytoplankton blooms with more light, nutrients
• Bloom continues until
• Nutrients run out
• Herbivores eat enough phytoplankton
• Summer often low production due to lack of
  nutrients
• Fall Often second bloom, as winds bring up
  nutrients

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Polar ocean productivity

• Winter darkness
• Summer sunlight (sometimes 24 hours/day)
• Phytoplankton (diatoms) bloom
• Zooplankton (mainly small crustaceans)
  productivity follows
• HIGH PRODUCTIVITY!!
• Example
• Arctic Ocean

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Tropical ocean productivity

• Permanent thermocline is barrier to vertical
  mixing
• Low rate of primary productivity (lack of
  nutrients) above thermocline
• Thats why tropical waters tend to be clear and
  blue

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Tropical ocean productivity

• Productivity in tropical ocean is lower than that
  of polar oceans
• Thats why tropical oceans look clear
• Tropical oceans are deserts with some high areas
  of sporadic productivity (oasis). Examples of
  these areas are
• Equatorial upwelling
• Coastal upwelling (river runoff, etc.)
• Coral reefs

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Energy flow in marine ecosystems

• Consumers eat other organisms
• Herbivores (primary consumers)
• Carnivores
• Omnivores
• Bacteriovores
• Decomposers breaking down dead organisms or waste
  products

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Nutrient flow in marine ecosystems

• Nutrients cycled from one chemical form to
  another
• Biogeochemical cycling
• Example, nutrients fixed by producers
• Passed onto consumers
• Some nutrients released to seawater through
  decomposers
• Nutrients can be recycled through upwelling

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Feeding strategies

• Suspension feeding or filter feeding
• Take in seawater and filter out usable organic
  matter
• Deposit feeding
• Take in detritus and sediment and extract usable
  organic matter
• Carnivorous feeding
• Organisms capture and eat other animals

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Trophic levels

• Feeding stage is trophic level
• Chemical energy is transferred from producers to
  consumers
• On average, about 10 of energy is transferred to
  next trophic level
• Much of the energy is lost as heat

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Food chain Food web

• Primary producer
• Herbivore
• One or more carnivores

• Branching network of many consumers
• Consumers more likely to survive with alternative
  food sources

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• Food webs are more complex more realistic
• Consumers often operate at two or more levels

http//users.aber.ac.uk/pmm1
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Marine fisheries

• Commercial fishing
• Most tonnage from continental shelves and coastal
  fisheries, compared to open ocean fisheries
• Over 20 of catch from areas of upwelling that
  make up 0.1 of ocean surface area

Fig. 13.23
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Overfishing

• Taking more fish than is sustainable over long
  periods
• Remaining fish younger, smaller
• About 30 of fish stocks depleted or overfished
• About 47 fished at biological limit

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• Aquaculture becoming a more significant component
  of world fisheries

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Incidental catch or bycatch

• Bycatch - Non-commercial species (or juveniles of
  commercial species) taken incidentally by
  commercial fishers
• Bycatch may be 25 or 800 of commercial fish
• Birds, turtles, dolphins, sharks

http//www.motherjones.com/news/featurex/2006/03/b
ycatch_265x181.jpg
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Incidental catch or bycatch

• Technology to help reduce bycatch
• Dolphin-safe tuna
• TEDs turtle exclusion devices
• Driftnets or gill nets banned in 1989
• Gill nets banned in Florida by constitutional
  amendment in 1994

http//www.st.nmfs.noaa.gov/st4/images/TurtTEDBlu_
small.jpg
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Fisheries management
http//www.cefas.co.uk/media/70062/fig10b.gif
Plaice

• Regulate fishing
• Closings Cod fisheries of New England
• Seasons
• Size limits
• Minimum size limits protects juveniles, less
  effective
• Min/max size (slot) limits preserves juvs and
  larger adults (contribute most reproductive
  effort)

http//www.cefas.co.uk/media/70037/fig7b.gif
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Fisheries management

• Conflicting interests
• Conservation vs. economic tragedy of the
  commons
• Self-sustaining marine ecosystems
• Human employment
• International waters
• Enforcement difficult

Tragedy of the commons All participants must
agree to conserve the commons, but any one can
force the destruction of the commons
http//farm1.static.flickr.com/178/380993834_09864
a282c.jpg
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Fisheries management

• Consumer choices in seafood
• Consume and purchase seafood from healthy,
  thriving fisheries
• Examples, farmed seafood, Alaska salmon
• Avoid overfished or depleted seafood
• Examples, bluefin tuna, shark, shrimp, swordfish
• Visit ORCA's Blue Diet page

http//marineresearch.ca/hawaii/wp-content/uploads
/tuna-auction-largeview.jpg
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Figure 13.28