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CH13_Outline - Ecological concepts: Feeding strategies...

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Unformatted text preview: Ecological concepts: Feeding strategies Ecological Suspension feeding or filter feeding Suspension Take in seawater and filter out usable organic matter: zooplankton, baleen whales, bivalves, barnacles, tube worms. bivalves, Deposit feeding Deposit Take in detritus and sediment and extract usable organic matter: burrowing worms, crabs, sea urchins (scavengers). crabs, Carnivorous feeding Carnivorous Organisms capture and eat other animals: arrow worms, euphausiids, fish, squid, euphausiids fish, marine mammals, starfish, reptiles marine Ecological concepts: Symbiosis Organisms associate in beneficial relationship relationship Commensalism Commensalism One benefits without harm to other One Mutualism Mutualism Mutually beneficial Mutually Parasitism Parasitism One benefits and may harm the other CHAPTER 13 CHAPTER Biological Productivity and Energy Biological Transfer Transfer Fig. 13.6 Primary productivity Primary Rate at which energy is stored in organic matter Rate Photosynthesis using solar radiation; chlorophyll Photosynthesis using concentrated in chloroplasts captures solar energy and converts it to chemical energy inside plant cells. plant Chemosynthesis using chemical reactions to Chemosynthesis using produce organic carbon instead of light energy produce 99.9% of marine life relies directly or indirectly on photosynthesis for food on Types of photosynthetic marine organisms Typ Anthophyta: seedbearing marine plants Only in shallow coastal waters waters Primarily seagrasses, salt seagrasses salt marsh grasses and marsh Mangroves Mangroves Fig. 13.7 Types of photosynthetic marine organisms Typ Macroscopic algae Seaweeds  Seaweeds  Brown algae: sargassum and kelp Green algae Green Red algae (most abundant and most Red (most widespread) widespread) Varied colors Varied Brown algae: Sargassum Brown algae: macrocystis or giant kelp Green algae: sponge weed (dead-man s fingers) Red Algae: pinkish coating on cobbles Types of photosynthetic marine organisms Typ Microscopic algae (5-300 m) 300 m) Produce food for 99% of marine animals Produce Most planktonic Most Golden algae Golden Diatoms (tests of silica SiO2) (tests Coccolithophores (plates of calcium carbonate CaCO3) (plates Dinoflagellates Red tide (harmful algal bloom) Red Toxins Toxins Fish kills Fish Human illness Human Diatom (50 m long) Coccolithophore (10-20 m) Dinoflagellate (70 m across) Dinoflagellate (100 m long) Massive fish kill from 1991 red-tide bloom off North Carolina Routes of exposure to dinoflagellate toxins: Pfiesteria life cycle stages: a. Toxic zoospore stage: kills fish b. Amoeba stage: feeds on dead fish c. Cyst stage: sinks to bottom Types of photosynthetic marine organisms Typ Photosynthetic bacteria: Photosynthetic cyanobacteria or blue-green cyanobacteria green algae algae Extremely small (0.6 m) m) May be responsible for half of total photosynthetic biomass in oceans oceans Photosynthesis Photosynthesis Chemical reaction that stores solar energy in organic molecules organic Fig. 13.1 Photosynthetic productivity Photosynthetic Gross primary production Gross Total amount of organic carbon produced by photosynthesis per unit time in certain area photosynthesis Net primary production Net Gross primary production minus cellular respiration (growth, reproduction, dark respiration) (growth, New production New Nutrients added to local ecosystem (e.g., atmospheric input and upwelling) input Regenerated production Regenerated Recycling of nutrients within ecosystem: regenerated ammonia from proteins ammonia Measuring primary productivity Measuring Capture plankton Capture Plankton nets Plankton Ocean color Ocean Chlorophyll colors seawater Chlorophyll SeaWiFs on satellite SeaWiFs Incubation experiments Incubation collect seawater with live phytoplankton collect 14 Add 14C as HCO3Incubate in-situ for 4-8 hours Incubate 14 Measure 14C uptake into organic matter. SeaWiFS satellite view (annual composite) of ocean SeaWiFS satellite chlorophyll and land vegetation (productivity) chlorophyll Note productive areas along equator and coastal upwelling zones upwelling Fig. 13-6 Factors affecting primary productivity productivity Nutrients Nutrients Nitrate, phosphorous, iron, silica Nitrate, Originally from river runoff and atmospheric input; regenerated in deep waters from sinking organic debris sinking Return to surface waters in upwelling areas along equator and coastal margins. along Solar radiation Solar Uppermost surface seawater and shallow seafloor seafloor Euphotic zone surface to about 100 m (330 ft) Euphotic Light transmission Visible light of the electromagnetic spectrum spectrum Blue wavelengths penetrate deepest penetrate Longer wavelengths (red, orange) and shorter UV absorbed first first Fig. 13.4 Light transmission in ocean Light Color of ocean ranges from deep blue to yellow-green to Factors Factors Turbidity from runoff Turbidity Photosynthetic pigment (chlorophyll) Photosynthetic Eutrophic  highly productive Oligotrophic  low nutrients, low productivity Oligotrophic Secchi disk (stanard size and color) lowered until not visible. Equals ½ of photic zone depth. Announcements: 1.Do not use the course web site to send personal emails to the rest of the class. They also go to the instructors and the TAs. Nutrient flow in marine ecosystems Nutrient Nutrients cycled from one chemical form to another to Nitrate (NO3-) = protein N Phosphate (PO43-) = DNA, lipids CO2 = organic carbon compounds Trace elements = enzymes Biogeo-chemical cycling Biogeo Example, nutrients fixed by producers Passed onto consumers Passed Some nutrients released to seawater through decomposers through Nutrients are returned to surface waters through upwelling waters Upwelling and nutrient supply Upwelling Cooler, deeper seawater is nutrient-rich Cooler, Areas of wind-driven coastal upwelling are sites Areas driven of high productivity of Fig. 13.3a 13_03b Tropical ocean productivity Tropical Plenty of light, but water column structure limits nutrient flux to surface waters Fig. 13.12 Tropical ocean productivity Tropical Permanent thermocline is barrier to vertical mixing vertical Low rate primary productivity (lack of nutrients) nutrients) High primary productivity in areas of High Equatorial upwelling Equatorial Coastal upwelling Coastal Coral reefs Coral Symbiotic algae Symbiotic Recycle nutrients within the ecosystem Recycle Temperate ocean productivity Temperate Limited by both available sunlight and available nutrients available Highly seasonal pattern Highly Temperate ocean productivity Temperate Spring phytopl. bloom (light+nutrients); summer zoopl. bloom (consume the phytopl. bloom); fall phytopl. bloom (pulse of regenerated nutrients); winter low productivity (light limited; nutrients high from winter mixing). Polar ocean productivity Polar Antarctica: Availability of 6 months of austral summer sunlight and high nutrients due to upwelling of North Atlantic Deep Water upwelling No thermocline barrier to vertical mixing mixing Fig. 13-11b Polar ocean productivity Polar Winter darkness; mixing brings nutrients to surface waters waters Summer sunlight; Phytoplankton (diatoms) bloom Summer Zooplankton (mainly small crustaceans) productivity follows follows Baleen whales come to feed on the zooplankton (krill). High productivity fuels productive food web (fish, marine birds and mammals). Fig. 13.11a Regional primary productivity Regional Varies from very low to very high depending on Varies Distribution of nutrients Distribution Seasonal changes in solar radiation Seasonal About 90% of surface biomass decomposed in surface ocean surface About 10% sinks to deeper ocean About Only 1% organic matter not decomposed in deep ocean deep Biological pump (CO2 and nutrients to sea floor Biological and sediments) sediments) Regional productivity summarized Regional Fig. 13.14 Energy flow in marine ecosystems Energy Ecosystem includes living organisms (biotic community) and environment community) Solar energy converted to chemical energy by producers (mainly photosynthesis) producers Consumers eat other organisms Consumers Herbivores Herbivores Carnivores Carnivores Omnivores Omnivores Bacteriovores Bacteriovores Decomposers breaking down dead organisms or Decomposers breaking waste products waste Food chain Food Primary producer Primary Herbivore Herbivore One or more carnivores carnivores Food web Primary producers Primary Branching network of many consumers consumers Consumers more likely to survive with alternative food sources food Food chain Food Web Fig. 13.20 Algae-supported biotic community Algae Fig. 13.15 Trophic levels Insert Fig. 13-18 Chemical energy is transferred from producers to consumers consumers Feeding stage is trophic level trophic About 10% of energy transferred to next trophic level trophic Passage of energy between trophic levels levels Fig. 13.19 Biomass Biomass pyramid pyramid Number of individuals and total biomass decrease 10x at higher trophic levels trophic Organisms increase in size increase Fig. 13.21 End of CHAPTER 13 Biological Productivity and Energy Transfer Transfer Fig. 13.25 Marine fisheries Marine Commercial fishing Commercial Most from continental shelves continental Over 20% from areas of upwelling that make up 0.1% of ocean surface area area Fig. 13.23 13_Gl 13_Gr Overfishing Taking more fish than sustainable Taking Remaining fish young, small Remaining About 30% of fish stocks depleted or overfished About About 47% fished at biological limit About Fig. 13.24 13_27 13_26 Incidental catch or bycatch Incidental Non-commercial species taken Non commercial incidentally by commercial fishers incidentally Bycatch may be 25% or 800% of commercial fish commercial Birds, turtles, dolphins, sharks Birds, Dolphin-safe tuna Dolphin Driftnets or gill nets banned in 1989 Driftnets Fisheries management Fisheries Regulate fishing Conflicting interests Conflicting Human employment Human Self-sustaining marine ecosystems Self International waters International Enforcement difficult Enforcement Fisheries management Fisheries Many large fishing vessels Many 1995 world fishing fleet spent $124 billion to catch $70 billion worth of fish worth Governments subsidize fishing Governments Fisheries management Fisheries Northwest Atlantic Fisheries such as Grand Banks and Georges Bank Banks Canada and U.S. restrict fishing and enforce bans enforce Some fish stocks in North Atlantic rebounding rebounding Other fish stocks still in decline (e.g., cod) Other Fisheries management Fisheries Consumer choices in seafood Consumer Consume and purchase seafood from healthy, thriving fisheries healthy, Examples, farmed seafood, Alaska salmon Examples, Avoid overfished or depleted seafood Avoid Examples, tuna, shark, shrimp Examples, 13_T02 13_F Feeding strategies Feeding Fig. 13.17d 13_11c 13_02 13_03c 13_T01 ...
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This note was uploaded on 02/27/2011 for the course OCE 1001 taught by Professor Staff during the Fall '08 term at FSU.

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