1. CHAPTER 13 Biological Productivity and Energy Transfer
Fig. 13.5

2. 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

3. 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)

4. 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

6. Measuring primary productivity
Capture plankton
Plankton nets
Ocean color
Chlorophyll colors seawater
SeaWiFs on satellite

7. 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
Solar radiation
Uppermost surface seawater and shallow seafloor are most productive, need light!
Euphotic zone surface to about 100 m (330 ft)

8. Upwelling and nutrient supply
Cooler, deeper seawater nutrient-rich
Areas of coastal upwelling sites of high productivity
Fig. 13.6a

9. Light transmission Visible light of the electromagnetic spectrum
Blue wavelengths penetrate deepest
Longer wavelengths (red, orange) absorbed first

10. 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)

11. 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

12. Anthophyta Only in shallow coastal waters
Primarily seagrasses & Mangroves
Very few plant species can tolerate salt water

13. Macroscopic algae – “Seaweeds”
Brown algae

14. Macroscopic algae – “Seaweeds”
Green algae
Caulerpa brachypus, an invasive species in the Indian River Lagoon
Codium

15. Macroscopic algae – “Seaweeds”
Red algae
Most abundant and most widespread of “seaweeds”
Varied colors

16. Microscopic algae Produce food for 99% of marine animals
Produce food for 99% of marine animals
Most planktonic
Golden algae
Diatoms (tests of silica)
Most abundant single-celled algae – spp.
Silicate skeletons – pillbox or rod-shaped  ooze
Some w/ sticky threads, spines  slows sinking
facilities/MEIAF

17. Microscopic algae Coccolithophores (plates of ate) Flagellated
calcium carbon plates  possibly sunshades
Coccolithid ooze  fossilized in white cliffs of Dover

18. 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)

19. concentrates on seagrass manatees eat
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

20. 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

21. Photosynthetic bacteria
Extremely small
May be responsible for half of total photosynthetic biomass in oceans
Anabaena
Gleocapsa

22. 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)

23. 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

24. 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

25. 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

26. 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

27. 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

28. Energy flow in marine ecosystems
Consumers eat other organisms
Herbivores (primary consumers)
Carnivores
Omnivores
Bacteriovores
Decomposers breaking down dead organisms or waste products

29. 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

30. 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

31. 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

33. 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

34. Food webs are more complex & more realistic
Consumers often operate at two or more levels

36. Biomass pyramid
Both number of individuals and total biomass (weight) decrease at successive trophic levels
Organisms increase in size

37. Symbiosis Organisms associate in beneficial relationship Commensalism
One benefits without harm to other
Mutualism
Mutually beneficial
Parasitism
One benefits and may harm the other

38. 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

39. 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

41. Aquaculture becoming a more significant component of world fisheries

42. 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

43. 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

44. Fisheries management Regulate fishing
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)

45. 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

46. Fisheries management 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
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

47. 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)

48. 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

49. Figure 13.28