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121 Cards in this Set
- Front
- Back
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What are threats to coral reefs?
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Sedimention, eutrophication, over fishing, water borne pathogens, global climate change.
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Sedimentation
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man/made/natural, covering coral reef w/ sedimentation (blocks sunlight) clogs polyp
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Eutrophication
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excess nutrients in system cause algae blooms, can overtake corals, murky water blocks sun
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Overfishing
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Cyanide, dynamite, and crowbars (break off corals)
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Water borne pathogens that effect coral
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black band disease, white band disease, white plague
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What are threats to coral reefs?
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Sedimention, eutrophication, over fishing, water borne pathogens, global climate change.
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Sedimentation
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man/made/natural, covering coral reef w/ sedimentation (blocks sunlight) clogs polyp
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Eutrophication
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excess nutrients in system cause algae blooms, can overtake corals, murky water blocks sun
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Overfishing
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Cyanide, dynamite, and crowbars (break off corals)
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Water borne pathogens that effect coral
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black band disease, white band disease, white plague
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What are the similarities between kelp forests and tropical rain forests?
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Lots of primary productivity/light, lots of organisms/diversity, and 3-dimensional habitat (floor, understory, canopy)
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What are the differences between kelp forests and tropical rain forests?
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water vs air, cold water only (more nutrients), kelp are algae (not true plants)
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What are some epifauna on kelp?
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sea urchins, snails, crabs, and other types of algae
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What primary producers are common in kelp forests?
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Kingdom Protista
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Phylum Phaeophyta
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brown algae, dominate kelp forest, mostly benthic
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Rhodophyta
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red algae-benthic
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Chlorophyta
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green algae-mostly benthic
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Chrysophyta
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single cellular diatoms/coccolithophores
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Dinophyta
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dinoflagellates
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What are characteristics/morphology of kelp?
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Blade, air bladder (pneumatocyst), holdfast, stipe
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Where is kelp found?
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nutrients/cold water
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Kelp zonation
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wave action (UL), light penetration (LL), and nutrients
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What is the lower boundary of kelp zonation?
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Lower boundary is set by light penetration and substrate. Kelp here has bigger air bladders
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What is the upper boundary of kelp zonation?
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Upper boundary set by wave action. Kelp here has a strong holdfast and flexible stipes
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trophic cascades
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when one/group of organisms or factors are eliminated and it affects the entire food chain/trophic system
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What is an example of bottom-up control?
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El Nino: less nutrients, kelp dies, less habitat for kelp forest organisms, and death
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bottom-up control
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when base of food chain effects the rest of the food chain
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What is an example of top-down control?
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predators are removed from overfishing, grazers (sea urchin) increase, kelp decreases=death
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Who are the top predators in a kelp forest that can effect top-down control?
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spiny lobster, california sheep head, sea otter
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Keystone species
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important species (removal/adding collapses system) ex:urchins
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Black Sea Bass
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Used to be common in kelp forests
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shifting baseline
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idea of community has shifted
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What are coral reefs made of?
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Many species of colonial cnidarian
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How is coral constructed?
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calcium carbonate skeleton, mouth/anus, gastrovascular cavity, and stinging cells
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cenosarc
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living coral tissue forms a thin interconnection over the surface of the reef
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What are some types of coral?
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Plate coral, brain coral, staghorn coral.
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Where are coral reefs?
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30 degree latitude on the equator, water 20 degrees celsius, eastern side of most continents. and they are in the photic zone
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Fringe reef
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border the shoreline
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Barrier reef
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offshore reef, separated from shore by a lagoon
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Atoll
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ring-shaped ocean reef, lagoon in the middle, sand builds up on top of the reef to create small islands, volcano sinks in middle
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How do corals obtain food?
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suspension/filter feed to catch zooplankton (mucus entrapment), symbiotic relationship with zooxanthella
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What is zooxanthella?
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Dinophyta/dinoflaggellates
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Mutalism
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both host (coral) and symbiont (zooxanthella) benefit
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commensalism
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host is unaffected by symbiont's benefit
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parasitism
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symbiont benefits at the expense of the host
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What benefits do coral receive from the zooxanthellae?
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organic products, don't need to spend energy to excrete waste, more energy to spend on growth and reproduction
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What benefits do zooxanthellae get from coral?
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protection, get nutrients (waste from coral/ nitrogen and phosphate)
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How much of what zooxathellae produce is used by coral?
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90-98%
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What other organisms have zooxanthellae?
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Nudibranch seaslugs, giant clam (blue, purple, red colors)
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hermatypic corals
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have zooxanthellae (dependent)
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ahermatypic corals
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lack zooxanthellae (non-reef building)
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Why are coral reefs important?
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build 3-D complex habitat which provides protection, highly productive and large diversity, leads to many niches
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What are the similarities between reefs and tide pools?
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complex habitat, highly productive, high diversity, lots of sessile organisms/broadcast spawning, zonation, space limitation, and competition
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What is an example of disease to a keystone species?
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Diadema (black sea urchin) is killed by pathogen, reduction of algal grazing, algae overgrow coral, corals die, community collapses
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How does global climate change effect coral?
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causes coral bleaching-coral becomes stressed out, expell zooxanthellae
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What causes coral bleaching?
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high temperatures, too much UV light
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epipelagic zone
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light is greater than 1%
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mesopelagic zone
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disphotic, "twilight"
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bathypelagic zone
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aphotic zone (no light)
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What is the deep sea dependent on?
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surface production except for hydrothermal vents/cold seeps
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What are characteristics of the surface water?
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warm, more light, low pressure, primary production
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What are characteristics of the deep sea?
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cold (0-4 celsius), no light, high pressure, very little primary production in deep sea.
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mesoplelagic organisms
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animals that migrate between the surface and deep sea (take advantage of both systems)
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What are the benefits of being in the deep sea during the day?
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stay hidden from predators, reduce metabolism/energetic costs
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What are the benefits of being up at the surface at night?
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feed in the photic zone
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diurnal vertical migration
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daily migration (fish, copepods, krill, jellies)
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What are characteristics of mesopelagic fish?
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well-developed eyes, muscles/nervous system are well developed, bioluminesence for counter shading, silvery sides
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What are characteristics of bathypelagic species?
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reduced eyes, reduced muscles/nervous system, bioluminescence (luring, seeing prey/mates), black/red, large mouths, dispensalbe (stretchy stomachs), large teeth
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hatchet fish
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photofors-on belly, mimic light from above/counter shading
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Japetella octopus
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clear/silvery, can change to black when illuminated by dragon fish photophors
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Azoic Theory
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Forbes, Pre-1850, theory was no life in deep sea
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Challenger Expedition
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(1872-76), life in deep sea
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Why is dwarfism prevalent in the deep sea?
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little food causes organisms to get smaller, lots of invertebrates
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What is the food source for the deep sea?
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surface: marine snow (particles of detritus), plant/animal falls, "plankton ladder", weak currents, and chemosynthesis
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What is a "plankton ladder"?
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primary production from surface gets transferred down through food chain
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What are the characteristics of the deep sea abyssal plain?
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fine sediment, mineralized skeletal remains of planktonic organisms, tiny organisms dominate, deposit feeding is main feeding strategy
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What is the time-stability hypothesis?
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stable environment-extreme specilization among competitng species for limited resources. many species=high diversity
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What is the disequilibrium hypothesis?
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local disturbances produce a patchy environment, micro habitats have own species, lots of diversity when viewed as whole
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What are biogenic structures in the deep sea?
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burrows, tubes/tracks, food falls, mounds, and gouges
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What are chemosynthetic communtities?
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not dependent on surface
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What are characteristics of hot vents?
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hydrogen sulfide, hard sediment, warm (20-400 celsius), black smokers/white smokers
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What are cold seeps?
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Methane/sulfide, soft sediment (silt/mud), cold (0-4 celsius) ambient temp
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When were hot vents discovered?
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1975 by ALVIN
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Where do vents occur?
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ocean ridges
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What is the basis of vent food chain?
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chemosynthetic bacteria
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What organisms are part of hot vent communities?
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crabs, worms, eels, clams, and mussels.
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What is the life time of Pacific Vents?
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10-50 years, organisms grow quickly, 10 months a full-blown fauna
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What is the life time of Atlantic vents?
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1000's of years, slow growing organisms
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What are the similarities between rocky intertidal and hot vent communities?
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hard substrate, high density/high biomass, competition for space/physical stressors lead to zonation
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gill nets
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drift gill nets, set gill nets (anchored), bycatch: dolphins, high bycatch, everything larger than the mesh of the net
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purse-seines
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bycatch: dolphins, non target fish
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trawls
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bycatch: highest, everything not fast enough to move out of the way
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long-lines
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bycatch: albatross and turtles, birds
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diving
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no bycatch, clean
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traps
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some bycatch of benthic fish
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harpoons
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no bycatch, clean
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rod+reel
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bycatch: non-target fish
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How much is the fishing industry worth?
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$80 billion
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How much was harvested in a year?
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100 million metric tons, plus 40 million tons of bycatch
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clupeoid fishes
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1/3 of world's total catch
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Benthic fishes
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10-15% total global catch
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Where are fish mainly caught?
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continental shelves/upwelling regions (90%)
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Maximum Sustainable unit
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MSY- past this point, fish biomass decreases
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MSE
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Maximum Sustainable Efforts
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Maximum Economic Yield
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MEY (most catch per unit effort), fishing at a level less MSY which means good fish growth
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What are some problems associated with fishing?
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over-exploitation, bycatch, fishmeal (not directly consumed by people), fish down foodweb changes trophic structure, no international regulations, fishing makes fish population more susceptible to enviromental changes, and habitat destruction
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"Tragedy of the commons"
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oceanic species outside jurisdiction of nations, lawless water
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How does coral reproduce?
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broadcast spawning
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crytofauno
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blend in w/ coral
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parrot fish
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keeps algae levels down
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What are bright colors used for?
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advertisement (poison)
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stripes
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throw off predators
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Peruvian Anchoveta
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el nino, then crash, 20 years for population to recover, next el nino fishery was closed, fishing went up
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Fishing down food web
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removing all the large fish first
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What are the benefits of fishing?
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Food and jobs
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What is Mariculture (Aquaculture)?
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growing and harvesting "fish", produces 20% of our marine food production
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What are the cons of mariculture?
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takes up land (wetlands), introduces disease into natural environment, create localized dead zones, kill fish to feed fish
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Management Organizations
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NOAA/ National Marine Fishery Service
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What do management organizations do?
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quotas, bag limits, fishing seasons, minimum/maximum size limit, regulations on gear use (net mesh size, depth of gear, location), limited entry (# of boats or lisences)
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International Comssions
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make binding agreements between nations, 200 mile wide exclusive economic zone (EEZs)-important because most fishing occurs on continental shelf
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How can we make a difference?
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Seafood watch, moratoriums, setting up marine reserves
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