Download Chapter 13: Biological productivity and energy transfer

CHAPTER 13
Biological Productivity and Energy Transfer
Fig. 13.5
Primary productivity

Rate at which energy is stored in organic
matter
 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
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
- Rest moves it’s way up the food chain
Measuring primary productivity


Capture plankton
 Plankton nets
Ocean color
 Chlorophyll colors seawater
 SeaWiFs on satellite
Factors affecting primary productivity

Nutrients
 Nitrate, phosphorous, iron, silica
 Most from river runoff
 Productivity high along continental margins

Solar radiation
 Uppermost surface seawater and shallow seafloor
 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.jpg
Light transmission
Visible light of the electromagnetic spectrum
 Blue wavelengths penetrate deepest
 Longer wavelengths (red, orange) absorbed
first

http://lh4.ggpht.com/_lQw_uDjiHTw/R7AmR74EByI/AAAAAAAAL40/VKg0nZ_Ih6c/DSC_0009.JPG
Light transmission in ocean

Color of ocean ranges
from deep blue to yellowgreen

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”
http://upload.wikimedia.org/wikipedia/commons/a/a5/LightningVolt_Deep_Blue_Sea.jpg
color)
Types of photosynthetic marine organisms
 Anthophyta
 Seed-bearing plants, example is
mangroves
 Macroscopic (large) algae
 Larger seaweeds, like kelp
 Microscopic
(small) algae
 phytoplankton
 Photosynthetic
bacteria
Anthophyta



Only in shallow coastal
waters
Primarily seagrasses &
Mangroves
Very few plant species can
tolerate salt water
http://celebrating200years.noaa.gov/events/sanctuaries/seagrass_meadow650.jpg
http://oceanexplorer.noaa.gov/explorations/02sab/logs/aug09/media/lines_600.jpg
Macroscopic algae – “Seaweeds”

Brown algae
Sargassum
http://www.starfish.ch/photos/plants-Pflanzen/Sargassum.jpg
Macroscopic algae – “Seaweeds”

Green algae
Caulerpa brachypus, an invasive species in the Indian River
Lagoon
Codium
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 planktonic

Golden algae

http://biologi.uio.no/akv/forskning/mbot/images
 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
http://epod.usra.edu/archive/images/coccolith.jpg
Microscopic algae

Dinoflagellates
 Mostly autotrophic; some heterotrophic or both
 Flagella in grooves for locomotion
 Many bioluminescent
 Often toxic
○
Red tides (algal blooms)  fish kills (increase nutrients, runoff)
Karenia spp., the alga that causes red tide
http://oceanworld.tamu.edu/students/fisheries/images/red_tide_bloom_1.jpghttp://www.hku.hk/ecology/porcupine/por24gif/Karenia-digitata.jpg
 Manatees died in Brevard
and Volusia counties in
2007, and on west coast,
possibly due to red tide
 concentrates on
seagrass manatees eat
 Breath in toxic fumes
http://www.nepa.gov.jm/yourenv/biodiversity/Sp
ecies/gifs/manatee.jpg
Microscopic algae

http://www.odu.edu/sci/biology/pfiesteria
Dinoflagellates
Pfiesteria in temperate coastal waters
 Ciguatera (from) Gambierdiscus toxicus

in tropical fishes
 Paralytic, diarhetic, amnesic shellfish
poisoning
Pfiesteria
Gambierdiscus
Alexandrium – paralytic shellfish
Alexandrium – paralytic shellfish
http://www.slv2000.qc.ca/bibliotheque/lefleuve/vol11no5/images_f/alexandrium1.jpg
http://www.hrw.com/science/si-science/
biology/plants/algae/ images/Gambitox.jpg
Photosynthetic bacteria
Extremely small
 May be responsible for half of total
photosynthetic biomass in oceans

Anabaena
http://www.micrographia.com/specbiol/bacteri/
bacter/bact0200/anabae03.jpg
Gleocapsa
http://silicasecchidisk.conncoll.edu/Pics/Other%20Algae/
Blue_Green%20jpegs/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)
Table 13.1
= 4785
Smaller than land but this is by meter2
(think about how large ocean is compared to land)
= 6450
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
Fig. 13.13
Polar ocean productivity
Availability of sunlight during
summer and
 High nutrients due to upwelling
of North Atlantic Deep Water

 No thermocline
 No barrier to vertical mixing

Blue whales migrate to feed on
maximum zooplankton
productivity
Tropical ocean productivity
Permanent thermocline is barrier to vertical mixing
 Low rate 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)

 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
Fig. 13-18
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
http://www-sci.pac.dfo-mpo.gc.ca/mehsd/images/ross_photos
Biomass
pyramid
Fig. 13.21

Both number of
individuals and
total biomass
(weight) decrease
at successive
trophic levels

Organisms
increase in size
Symbiosis

Organisms associate in
beneficial relationship
 Commensalism
○ One benefits without
harm to other
 Mutualism
○ Mutually beneficial
 Parasitism
○ One benefits and may
harm the other
Marine fisheries


Commercial fishing
Most tonnage from
continental shelves
and coastal fisheries,
compared to open
ocean fisheries

Fig. 13.23
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

State of exploitation
of selected stock or
species groups for
which assesment
information is
available, by major
marine fishing areas,
2004
http://www.fao.org/docrep/009/y5852e/Y5852E08.jpg
http://www.fao.org/docrep/009/y5852e/Y5852E12.jpg
Figure A2.4 - Stage of development of the 200
major marine fishery resources: 1950–2000

Aquaculture becoming a more significant
component of world fisheries
Marine fisheries leveling off
over last 10-15 years
http://www.fao.org/docrep/009/y5852e/Y5852E02.jpg
Figure 13.26
http://gristmill.grist.org/images/admin/By_Catch_On_Boat.jpg
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
http://www.int-res.com/uploads/pics/esrspecial-bycatch_01.jpg
http://ourworld.compuserve.com/homepages/CVisco/tuna.gif
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.teara.govt.nz/NR/rdonlyres/A5B74D1E5BD8-4D7B-B75D-F1480DC74C5D/207170/p6281atl.jpg
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://dieoff.org/page109.htm
http://farm1.static.flickr.com/178/380993834_09864a282c.jpg
Fisheries management

http://newsroom.nt.gov.au/adminmedia/mailouts/3879/
attachments/Indonesian%20fishing%20boat%202.JPG
Governments subsidize fishing
 Many large fishing vessels – often
purchased with economic
stimulus loans
 1995 world fishing fleet spent
$124 billion to catch $70 billion
worth of fish
34m Fishing Vessel Apprehended
In Australian Waters, April 2008
Activists deploying a banner
reading, 'No Fish No Future'
next to tuna fishing vessel
Albatun Tre, which they claim
is the world's largest tuna
fishing vessel
http://www.telegraph.co.uk/earth/main.jhtml?xml=/earth/2008/05/30/eatuna130.xml
http://yukna.free.fr/science/zebramussels/300px-Grand_Banks.png
Fisheries management
Northwest Atlantic Fisheries
such as Grand Banks and
Georges Bank
 Canada and U.S. restrict
fishing and enforce bans
 Some fish stocks in North
Atlantic rebounding
 Other fish stocks still in
decline (e.g., cod)

http://content.answers.com/main/content/wp/en/thumb/7/7d/300px-GulfofMaine.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