Download Chapter 13: Biological productivity and energy

Primary Productivity in the Marine Environment
Fig. 13.5
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

Remember, energy cannot be created
or destroyed – it only changes form
Let’s 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)
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 it’s way up the food chain


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

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/photosynthesis/?utm_campaign=s
hare&utm_medium=copy

Cellular Respiration
 Review this Prezi: http://prezi.com/8_qehzkw-
vuk/cellularrespiration/?utm_campaign=share&utm_medium=c
opy

Is glucose the only molecule that can be
broken down and oxidized during cellular
respiration to gain energy?
Measuring primary productivity


Capture plankton
 Plankton nets
Ocean color
 Chlorophyll colors seawater
 SeaWiFs on satellite
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)
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/upwelling_470.jp
Light transmission
Visible light of the electromagnetic spectrum
 Blue wavelengths penetrate deepest
 Longer wavelengths (red, orange) absorbed
first

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
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
Macroscopic algae – “Seaweeds”

Brown algae
http://www.starfish.ch/photos/plants-Pflanzen/Sargassum.jpg
Macroscopic algae – “Seaweeds”

Green algae
Codium
Caulerpa brachypus, an invasive
species in the Indian River Lagoon
http://www.sms.si.edu/IRLspec/images/cbrachypus2.jpg
http://192.107.66.195/Buoy/System_Description_Codium_Fragile.jpg
Macroscopic algae – “Seaweeds”

Red algae
 Most abundant and most widespread
of “seaweeds”
 Varied colors
http://www.dnrec.state.de.us/MacroAlgae/information/Indentifying.shtml
http://www.agen.ufl.edu/~chyn/age2062/lect/lect_15/22_14B.GIF
Microscopic algae
Produce food for 99% of marine
animals
 Most are planktonic phytoplankton


http://biologi.uio.no/akv/forskning/mbot/images
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
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
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://oceanworld.tamu.edu/students/fisheries/images/red_tide_bloom_1.jpg
http://www.hku.hk/ecology/porcupine/por24gif/Karenia-digitata.jpg
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
Photosynthetic bacteria
Cyanobacteria – many different species
 Extremely small
 May be responsible for half of total
photosynthetic biomass in oceans

Anabaena
http://www.micrographia.com/specbiol/bacteri/bacter/bact0
200/anabae03.jpg
Gleocapsa
http://silicasecchidisk.conncoll.edu/Pics/Other%20Algae/Blue_Green%20
jpegs/Gloeocapsa_Key45.jpg
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)
Temperate ocean productivity

Seasonal variation with temperature/light/nutrients
 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
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
Tropical ocean productivity
Permanent thermocline is barrier to vertical
mixing
 Low rate of primary productivity (lack of
nutrients) above thermocline

○ That’s why tropical waters tend to be clear and blue
Tropical ocean productivity
Productivity in tropical ocean is lower than
that of polar oceans
 That’s 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
Energy flow in marine ecosystems

Consumers eat other organisms





Herbivores (primary consumers)
Carnivores
Omnivores
Bacteriovores
Decomposers breaking down dead organisms
or waste products
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
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
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
Food chain



Primary producer
Herbivore
One or more carnivores
Food web


Branching network of
many consumers
Consumers more likely
to survive with
alternative food sources
•
Food webs are more complex & more realistic
• Consumers often operate at two or more levels
http://users.aber.ac.uk/pmm1
Marine fisheries



Fig. 13.23
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
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

Aquaculture becoming a more significant
component of world fisheries
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/bycatch_265x181.jpg
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
http://www.cefas.co.uk/media/70062/fig10b.gif
Fisheries management

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
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_09864a282c.jpg
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/wpcontent/uploads/tuna-auction-largeview.jpg
Figure 13.28