Biological Productivity and Energy Transfer

Primary Productivity “The rate at which energy is stored by organisms through the formation of organic matter using energy derived from solar radiation or chemical reactions” Photosynthesis Chemosynthesis

Primary Productivity Photosynthetic Productivity

Primary Productivity Gross Primary Production Total amount of organic carbon produced by photosynthesis per unit time Includes New production Regenerated production

Primary Productivity Net Primary Production Gross primary production – cellular respiration Results in growth & reproduction

Primary Productivity Measurement of Primary Productivity Plankton nets Amount of chlorophyll

Seasonal Global Primary Production Maps - Winter Source: http://marine.rutgers.edu./opp/swf/Production/gif_files/PP_9712_9802.gif

Seasonal Global Primary Production Maps - Summer Source: http://marine.rutgers.edu./opp/swf/Production/gif_files/PP_9906_9908.gif

Primary Productivity Factors Affecting Primary Productivity Available Nutrients Available Solar Radiation

Primary Productivity Ocean Margins Upwelling and Nutrient Supply The Benguela Upwelling Zone - Annual Area Average Plots (http://daac.gsfc.nasa.gov/oceancolor/tutorials/module3.shtml) The Benguela Upwelling Zone -- Annual Area Average Plots      In the SST image, the location of the coldest upwelled water is observed to be very close to the coast.       In the chlorophyll image, the dramatic effect of the nutrients provided by the upwelling process can be seen.   Also note the much warmer water of the Agulhas Current south of the African continent, and the distribution of chlorophyll corresponding to the Agulhas Current.

Primary Productivity Light Transmission in Ocean Water Solar radiation creates: Atmospheric circulation, ocean circulation and waves A layer of warm water at the surface photosynthesis

Electromagnetic Spectrum

Photosynthetic Marine Organisms Seed-Bearing Plants (Anthophyta) Shallow coastal waters (< 6 m) Include Seagrass Grasses (salt marshes) mangroves Surfgrass (Phyllospadix torreyi) Source: http://www.marine.gov

Photosynthetic Marine Organisms Macroscopic (Large) Algae aka “seaweeds” Shallow waters of the coastal margins Include: Brown algae Size varies Upper & middle intertidal zone Kelp forests Food in intertidal zone Pacific Rockweed (Fucus distichus) in Olympic National Park Source: http://en.wikipedia.org

Photosynthetic Marine Organisms Macroscopic (Large) Algae aka “seaweeds” Shallow waters of the coastal margins Include: Green algae Intertidal or shallow bays Sea lettuce & sponge weed A growth of the green seaweed, Enteromorpha on rock substratum at the ocean shore. Source: http://en.wikipedia.org

Photosynthetic Marine Organisms Macroscopic (Large) Algae aka “seaweeds” Shallow waters of the coastal margins Include: Red algae Most abundant Highest intertidal zone to outer edge of the sublittoral zone Attached to the bottom Several species of red algae grow on rhodoliths at about 75 m depth (225 ft) on McGrail Bank. Source: oceanexplorer.noaa.gov

Photosynthetic Marine Organisms Microscopic (Small) Algae Base of food chain Include: Golden Algae Diatoms Coccolithophores Dinoflagellates Acinetospora crinita Source: http://www.algaebase.org

Photosynthetic Marine Organisms Synechococcus Source: http://www.lbl.gov/ Photosynthetic Bacteria May be responsible for nearly half of the primary production of food in the ocean Able to reduce nitrogen and carbon in aerobic conditions Prochlorococcus Source: http://www.lbl.gov/

Regional Productivity Productivity in Polar Oceans Productivity in Tropical Oceans Productivity in Temperate Oceans

Regional Productivity Polar Oceans Continuous darkness for three months Continuous sunlight for three months Productivity higher in the Antarctic due to upwelling Tropical Oceans Temperate Oceans

Polar Productivity Highly seasonal phytoplankton blooms characterize these polar waters, where photosynthesis is strongly influenced by the availability of light. Note differences in Artic (left) and Antarctic (right) summers where the ocean is surrounded by land and the land surrounded by ocean, respectively. Source: http://disc.gsfc.nasa.gov/oceancolor/scifocus/space/ocdst_polar_productivity.shtml

Regional Productivity Tropical Oceans Deep light penetration produces layering of water masses Prevents mixing of waters & nutrients from upwelling Production about 1/2 of temperate oceans Exceptions: Equatorial & Coastal Upwelling Coral Reefs

Productivity in Tropical Oceans

Regional Productivity Temperate Oceans Productivity limited by available sunlight & nutrient supply Winter Spring Summer Fall Productivity Low High (spring bloom) High (fall bloom) Nutrient levels Highest Decreasing Lowest Increasing Sunlight

Productivity in Temperate Oceans

Energy Flow and Nutrient Cycling Energy Flow in Marine Ecosystems Biotic Community – assemblage of organisms that live together within a definable area Ecosystem – includes the biotic community + the environment with which it exchanges energy & chemical substances Three categories of organisms: Producers, consumers and decomposers

Energy Flow and Nutrient Cycling Biogeochemical Cycling Includes: nitrogen cycle oxygen cycle carbon cycle phosphorus cycle sulfur cycle water cycle hydrogen cycle

Oceanic Feeding Relationships Feeding Strategies Suspension feeding (filter feeding) Deposit feeding Carnivorous feeding

Oceanic Feeding Relationships Trophic Levels Chemical energy stored by plants is transferred to the animal community via feeding Each stage is called a tropic level

Oceanic Feeding Relationships Transfer Efficiency Transfer of energy between trophic levels is inefficient

Oceanic Feeding Relationships Food Chains, Food Webs, and the Biomass Pyramid Food chains – a sequence of organisms through which energy is transferred from primary producer up to the top carnivores

Oceanic Feeding Relationships Food Chains, Food Webs, and the Biomass Pyramid Food webs – top carnivores feed off of numerous animals that have their own food chain or web

Oceanic Feeding Relationships Food Chains, Food Webs, and the Biomass Pyramid Biomass Pyramid – the number of individuals & total biomass decrease through successive trophic levels as the amount of available energy decreases

Oceanic Feeding Relationships Symbiosis Occurs when two or more organisms associate in a way that benefits at least one of them Commensalim – smaller group benefits, host not affected Mutualism – both groups benefit Parasitism – one group benefits at another’s expense

Issues Affecting Marine Fisheries Overfishing When harvesting of fish stocks takes place so rapidly that the majority of the population is sexually immature and is therefore unable to reproduce Affects the size of the fishes (smaller)

Issues Affecting Marine Fisheries Overfishing Whaling The whaling industry has pushed most of the dozen species of great whales to the brink of extinction.

Issues Affecting Marine Fisheries Overfishing Fur-Bearing Mammals Sea Otter Harbor Seals Sea Lion

Issues Affecting Marine Fisheries Incidental Catch Organisms which are caught by accident with the rest of the catch Tuna and Dolphins

Issues Affecting Marine Fisheries Fishery Management Fishing employs fifteen million people worldwide. Fish, Crustaceans, And Mollusks the most valuable living marine resources. © 2002 Brooks/Cole, a division of Thomson Learning, Inc.

Biological Resources Some of the major types of commercially harvested fish, mollusks and crustaceans. © 2002 Brooks/Cole, a division of Thomson Learning, Inc.

Issues Affecting Marine Fisheries Fishery Mismanagement Maximum sustainable yield - the maximum amount of any species that can be harvested without affecting future yields Overfished - a status assigned to fish stocks that have been harvested so there is not enough breeding stock left for replenishment © 2002 Brooks/Cole, a division of Thomson Learning, Inc.

Issues Affecting Marine Fisheries Fishery Mismanagement Commercial extinction - the depletion of a species to the point where it is no longer profitable to harvest Bykill - animals unintentionally killed when other species are being harvested © 2002 Brooks/Cole, a division of Thomson Learning, Inc.

Issues Affecting Marine Fisheries Effects on California Economy Market Value of Industries $17.3 Billion, Supporting 370,000 Jobs (1992 data) Commercial Fishing, Mariculture and Kelp Harvesting Includes tuna, sea urchin, rockfish, crab, and salmon $554 million to the state's economy 17,000 jobs Source: California's Ocean Resources: An Agenda for the Future (1995)

Issues Affecting Marine Fisheries How Fish are Caught - Unfriendly Dredging Dredgers rake the seafloor for shellfish. Dredging damages the seafloor and results in unintentional catch Gillnetting The size of a gillnet's mesh determines the type of fish it will catch. Gillnets may accidentally entangle and kill sea turtles Longlining Longlines at different depths attract different species. Pelagic longlining can accidentally kill sea turtles and seabirds Source: www.seafoodwatch.org

Issues Affecting Marine Fisheries How Fish are Caught - Unfriendly Purse Seining Purse seines are primarly used for schooling fish. Purse seining for tuna results in large amounts of unintended catch Trawling/Dragging Trawling at different depths catches different animals. Trawl nets catch everything in their path and can damage the seafloor Traps and Pots Traps and pots catch bottom-dwellers. Most traps and pots are environmentally responsible, but have issues too Source: www.seafoodwatch.org

Issues Affecting Marine Fisheries How Fish are Caught - Friendly Hook and Lining Hook and liners fish near the surface and down below Hook and lining is an environmentally responsible fishing method Traps and Pots Traps and pots catch bottom-dwellers. Most traps and pots are environmentally responsible, but have issues too Harpooning Harpooners catch large, pelagic predators such as bluefin tuna & swordfish. An environmentally responsible fishing method Source: www.seafoodwatch.org

Issues Affecting Marine Fisheries How Fish are Farmed – Unfriendly Open Net Pens or Cages Waste passes freely into the surrounding environment. Escaped fish compete with wild fish for natural resources. Escaped fish can interbreed with wild fish of the same species, compromising the hardiness of the wild population. Diseases and parasites can spread to wild fish living near or swimming past net pens. Source: www.seafoodwatch.org

Issues Affecting Marine Fisheries How Fish are Farmed – Unfriendly Ponds Ponds enclose fish in a coastal or inland body of fresh or salt water. Wastewater can be contained and treated. The construction of shrimp ponds in mangrove forests has destroyed more than 3.7 million acres of coastal habitat. Untreated wastewater can pollute the surrounding environment and contaminate groundwater. Source: www.seafoodwatch.org

Issues Affecting Marine Fisheries How Fish are Farmed – Unfriendly Raceways Water is usually treated before returning it. Strict regulation and monitoring required Untreated wastewater can contaminate waterways and spread diseases. Escaped fish can Compete with wild fish for natural resources Interbreed with wild fish of the same species Source: www.seafoodwatch.org

Issues Affecting Marine Fisheries How Fish are Farmed – Friendly Recirculating Systems Recirculating systems address many environmental concerns associated with fish farming: fish cannot escape, and wastewater is treated. Costly to operate and rely on electricity or other power sources. Source: www.seafoodwatch.org

Issues Affecting Marine Fisheries How Fish are Farmed – Friendly Shellfish Culture Shellfish are grown on beaches or suspend them in water by ropes, plastic trays or mesh bags. Since oysters, mussels and clams are filter feeders, they can actually cleanse nutrient-rich water. Farming in high densities in areas with little current or tidal flow can lead to the accumulation of waste. Responsible for the introduction of exotic species Source: www.seafoodwatch.org

Issues Affecting Marine Fisheries Seafood Choices www.seafoodwatch.org "Best Choices" are abundant, well managed and fished or farmed in environmentally friendly ways. Seafood to "Avoid" are overfished and/or fished or farmed in ways that harm other marine life or the environment. Your consumer choices make a difference. Buy seafood from the green or yellow columns to support those fisheries and fish farms that are healthier for ocean wildlife and the environment. Source: www.seafoodwatch.org

Source: www.seafoodwatch.org

~ END ~