CHAPTER 13 Biological Productivity and Energy Transfer Fig. 13.5

Primary productivity Rate at which energy is stored in organic matter Rate at which energy is stored in organic matter Photosynthesis using solar radiation Photosynthesis using solar radiation Chemosynthesis using chemical reactions Chemosynthesis using chemical reactions 99.9% of marine life relies directly or indirectly on photosynthesis for food 99.9% of marine life relies directly or indirectly on photosynthesis for food

Photosynthetic productivity Chemical reaction that stores solar energy in organic molecules Chemical reaction that stores solar energy in organic molecules Fig. 13.1

Photosynthetic productivity Gross primary production Gross primary production Total amount of organic carbon produced by photosynthesis per unit time in certain area Total amount of organic carbon produced by photosynthesis per unit time in certain area Net primary production Net primary production Gross primary production minus cellular respiration (growth, reproduction) Gross primary production minus cellular respiration (growth, reproduction) New production New production Nutrients added to local ecosystem (e.g., upwelling) Nutrients added to local ecosystem (e.g., upwelling) Regenerated production Regenerated production Recycling of nutrients within ecosystem Recycling of nutrients within ecosystem

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

Factors affecting primary productivity Nutrients Nutrients Nitrate, phosphorous, iron, silica Nitrate, phosphorous, iron, silica Most from river runoff Most from river runoff Productivity high along continental margins Productivity high along continental margins Solar radiation Solar radiation Uppermost surface seawater and shallow seafloor Uppermost surface seawater and shallow seafloor Euphotic zone surface to about 100 m (330 ft) Euphotic zone surface to about 100 m (330 ft)

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

Light transmission Visible light of the electromagnetic spectrum Visible light of the electromagnetic spectrum Blue wavelengths penetrate deepest Blue wavelengths penetrate deepest Longer wavelengths (red, orange) absorbed first Longer wavelengths (red, orange) absorbed first Fig. 13.3

Light transmission Fig. 13.3

Light transmission in ocean Color of ocean ranges from deep blue to yellow-green Color of ocean ranges from deep blue to yellow-green Factors Factors Turbidity from runoff Turbidity from runoff Photosynthetic pigment (chlorophyll) Photosynthetic pigment (chlorophyll) Eutrophic Eutrophic Oligotrophic Oligotrophic

Light transmission in ocean SeaStar satellite/SeaWiFS view of ocean chlorophyll and land vegetation (productivity) SeaStar satellite/SeaWiFS view of ocean chlorophyll and land vegetation (productivity) Fig. 13-5

Types of photosynthetic marine organisms Anthophyta Anthophyta Seed-bearing plants Seed-bearing plants Macroscopic (large) algae Macroscopic (large) algae Microscopic (small) algae Microscopic (small) algae Photosynthetic bacteria Photosynthetic bacteria

Anthophyta Only in shallow coastal waters Only in shallow coastal waters Primarily grasses and Primarily grasses and Mangroves Mangroves Fig. 13.7

Macroscopic algae “Seaweeds” “Seaweeds” Brown algae Brown algae Green algae Green algae Red algae (most abundant and most widespread) Red algae (most abundant and most widespread) Varied colors Varied colors

Microscopic algae Produce food for 99% of marine animals Produce food for 99% of marine animals Most planktonic Most planktonic Golden algae Golden algae Diatoms (tests of silica) Diatoms (tests of silica) Coccolithophores (plates of calcium carbonate) Coccolithophores (plates of calcium carbonate) Dinoflagellates Dinoflagellates Red tide (harmful algal bloom) Red tide (harmful algal bloom) Toxins Toxins Fish kills Fish kills Human illness Human illness

Photosynthetic bacteria Extremely small Extremely small May be responsible for half of total photosynthetic biomass in oceans May be responsible for half of total photosynthetic biomass in oceans

Regional primary productivity Varies from very low to very high depending on Varies from very low to very high depending on Distribution of nutrients Distribution of nutrients Seasonal changes in solar radiation Seasonal changes in solar radiation About 90% of surface biomass decomposed in surface ocean About 90% of surface biomass decomposed in surface ocean About 10% sinks to deeper ocean About 10% sinks to deeper ocean Only 1% organic matter not decomposed in deep ocean Only 1% organic matter not decomposed in deep ocean Biological pump (CO 2 and nutrients to sea floor sediments) Biological pump (CO 2 and nutrients to sea floor sediments)

Polar ocean productivity Winter darkness Winter darkness Summer sunlight Summer sunlight Phytoplankton (diatoms) bloom Phytoplankton (diatoms) bloom Zooplankton (mainly small crustaceans) productivity follows Zooplankton (mainly small crustaceans) productivity follows Example Example Arctic Ocean Fig

Polar ocean productivity Availability of sunlight and Availability of sunlight and High nutrients due to upwelling of North Atlantic Deep Water High nutrients due to upwelling of North Atlantic Deep Water No thermocline No thermocline No barrier to vertical mixing No barrier to vertical mixing Blue whales migrate to feed on maximum zooplankton productivity Blue whales migrate to feed on maximum zooplankton productivity

Fig b

Tropical ocean productivity Permanent thermocline is barrier to vertical mixing Permanent thermocline is barrier to vertical mixing Low rate primary productivity (lack of nutrients) Low rate primary productivity (lack of nutrients) High primary productivity in areas of High primary productivity in areas of Equatorial upwelling Equatorial upwelling Coastal upwelling Coastal upwelling Coral reefs Coral reefs Symbiotic algae Symbiotic algae Recycle nutrients within the ecosystem Recycle nutrients within the ecosystem

Fig

Temperate ocean productivity Limited by both available sunlight and Limited by both available sunlight and Available nutrients Available nutrients Highly seasonal pattern Highly seasonal pattern Winter low (lots of nutrients, little sunlight) Winter low (lots of nutrients, little sunlight) Spring high (spring bloom) Spring high (spring bloom) Summer low (little nutrients, lots of sunlight) Summer low (little nutrients, lots of sunlight) Fall high (fall bloom) Fall high (fall bloom)

Regional productivity summarized Fig

Energy flow in marine ecosystems Ecosystem includes living organisms (biotic community) and environment Ecosystem includes living organisms (biotic community) and environment Solar energy converted to chemical energy by producers (mainly photosynthesis) Solar energy converted to chemical energy by producers (mainly photosynthesis) Consumers eat other organisms Consumers eat other organisms Herbivores Herbivores Carnivores Carnivores Omnivores Omnivores Bacteriovores Bacteriovores Decomposers breaking down dead organisms or waste products Decomposers breaking down dead organisms or waste products

Algae-supported biotic community Fig

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

Fig Biogeo- chemical cycling

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

Feeding strategies Fig d

Trophic levels Chemical energy is transferred from producers to consumers Chemical energy is transferred from producers to consumers Feeding stage is trophic level Feeding stage is trophic level About 10% of energy transferred to next trophic level About 10% of energy transferred to next trophic level Fig

Passage of energy between trophic levels Fig

Food chain Food web Primary producer Primary producer Herbivore Herbivore One or more carnivores One or more carnivores Branching network of many consumers Branching network of many consumers Consumers more likely to survive with alternative food sources Consumers more likely to survive with alternative food sources

Fig

Biomass pyramid Number of individuals and total biomass decrease at successive trophic levels Number of individuals and total biomass decrease at successive trophic levels Organisms increase in size Organisms increase in size Fig

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

Commercial fishing Commercial fishing Most from continental shelves Most from continental shelves Over 20% from areas of upwelling that make up 0.1% of ocean surface area Over 20% from areas of upwelling that make up 0.1% of ocean surface area Fig Marine fisheries

Overfishing Taking more fish than sustainable Taking more fish than sustainable Remaining fish young, small Remaining fish young, small About 30% of fish stocks depleted or overfished About 30% of fish stocks depleted or overfished About 47% fished at biological limit About 47% fished at biological limit Fig

Incidental catch or bycatch Non-commercial species taken incidentally by commercial fishers Non-commercial species taken incidentally by commercial fishers Bycatch may be 25% or 800% of commercial fish Bycatch may be 25% or 800% of commercial fish Birds, turtles, dolphins, sharks Dolphin-safe tuna Driftnets or gill nets banned in 1989 Driftnets or gill nets banned in 1989

Fisheries management Regulate fishing Regulate fishing Conflicting interests Conflicting interests Human employment Human employment Self-sustaining marine ecosystems Self-sustaining marine ecosystems International waters International waters Enforcement difficult Enforcement difficult

Fisheries management Many large fishing vessels Many large fishing vessels 1995 world fishing fleet spent $124 billion to catch $70 billion worth of fish 1995 world fishing fleet spent $124 billion to catch $70 billion worth of fish Governments subsidize fishing Governments subsidize fishing

Fisheries management Northwest Atlantic Fisheries such as Grand Banks and Georges Bank Northwest Atlantic Fisheries such as Grand Banks and Georges Bank Canada and U.S. restrict fishing and enforce bans Canada and U.S. restrict fishing and enforce bans Some fish stocks in North Atlantic rebounding Some fish stocks in North Atlantic rebounding Other fish stocks still in decline (e.g., cod) Other fish stocks still in decline (e.g., cod)

Fisheries management Consumer choices in seafood Consumer choices in seafood Consume and purchase seafood from healthy, thriving fisheries Consume and purchase seafood from healthy, thriving fisheries Examples, farmed seafood, Alaska salmon Examples, farmed seafood, Alaska salmon Avoid overfished or depleted seafood Avoid overfished or depleted seafood Examples, tuna, shark, shrimp Examples, tuna, shark, shrimp

End of CHAPTER 13 Biological Productivity and Energy Transfer Fig