© 2011 Pearson Education, Inc. CHAPTER 13 Biological Productivity

© 2011 Pearson Education, Inc. Primary Productivity Photosynthesis uses solar radiation. Chemosynthesis uses chemical reactions. 99.9% of the ocean’s biomass relies directly or indirectly on photosynthesis for food. Ocean productivity equal to Land

© 2011 Pearson Education, Inc. Photosynthetic Marine Organisms Macroscopic (large) algae Microscopic (small) algae Photosynthetic bacteria

© 2011 Pearson Education, Inc. Microscopic Algae Produce food for 99% of marine animals Most planktonic Golden algae –Diatoms – tests made of silica –Coccolithophores – plates of calcium carbonate Dinoflagellates –Red tide (harmful algal bloom) –Toxins –Fish kills –Human illness

© 2011 Pearson Education, Inc. Microscopic Algae

© 2011 Pearson Education, Inc. Photosynthetic Bacteria Extremely small May be responsible for half of total photosynthetic biomass in oceans

© 2011 Pearson Education, Inc. Macroscopic Algae “Seaweeds” Brown algae Green algae Red algae

© 2011 Pearson Education, Inc. Energy Flow in Marine Systems

© 2011 Pearson Education, Inc. Factors Affecting Primary Productivity Nutrient availability –Nitrate, phosphorous, iron, silica –Upwelling and river runoff

© 2011 Pearson Education, Inc. Factors Affecting Primary Productivity Solar radiation –Uppermost surface seawater and shallow seafloor –Compensation depth – net photosynthesis becomes zero –Euphotic zone—from surface to about 100 meters (330 feet)

© 2011 Pearson Education, Inc. Color in the Ocean Secchi Disk – measures water transparency Green Photoplankton Blue-no or zooplankton Red-dinoflagellates/red tide

© 2011 Pearson Education, Inc. Measurement of Primary Productivity Directly – Nets Measure radioactive carbon in seawater Monitor ocean color with satellites –Green pigment chlorophyll

© 2011 Pearson Education, Inc. Upwelling and Nutrient Supply Cooler, deeper seawater is nutrient-rich. Areas of coastal upwelling are sites of high productivity.

© 2011 Pearson Education, Inc. Upwelling and Nutrient Supply

© 2011 Pearson Education, Inc. Comparison of Global Productivities

© 2011 Pearson Education, Inc. Polar Ocean Productivity Winter darkness Summer sunlight Phytoplankton (diatoms) bloom Zooplankton (mainly small crustaceans) productivity follows Example: Arctic Ocean’s Barents Sea

© 2011 Pearson Education, Inc. Polar Ocean Productivity No thermocline Plankton remain at surface Blue whales migrate to feed on maximum zooplankton productivity.

© 2011 Pearson Education, Inc. Productivity in Tropical Oceans Permanent thermocline is barrier to vertical mixing Low rate of primary productivity – lack of nutrients

© 2011 Pearson Education, Inc. Productivity in Tropical Oceans High primary productivity in areas of –Equatorial upwelling –Coastal upwelling –Coral reefs Recycle nutrients within the ecosystem

© 2011 Pearson Education, Inc. Temperate Ocean Productivity Productivity limited by –Available sunlight –Available nutrients

© 2011 Pearson Education, Inc. Comparison of Global Productivities

© 2011 Pearson Education, Inc. Energy Flow in Marine Systems Producers –photosynthesis or chemosynthesis –Autotrophic Consumers –Eat other organisms –Heterotrophic Decomposers – break down dead organisms or waste

© 2011 Pearson Education, Inc. Energy Flow in Marine Systems

© 2011 Pearson Education, Inc. Trophic Levels

© 2011 Pearson Education, Inc. Adaptations to Avoid Predation Symbiotic Relationships Mutualism – both organisms benefit Parasitism- parasite benefits at expense of host Commensalism – benefits one without harming host

© 2011 Pearson Education, Inc. Mutualism Both organisms benefit

© 2011 Pearson Education, Inc. Parasites Benefits at expense of host

© 2011 Pearson Education, Inc. Parasites Benefits at expense of host

© 2011 Pearson Education, Inc. Commensalism Benefits one without harming host