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24 Cards in this Set
- Front
- Back
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Hydrothermal vents
Occur at |
ocean-spreading centers worldwide
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What are hydrothermal vents
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• Fissures or chimneys in ocean crust where geothermally heated water released
-undersea hot sprigs |
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• Dense chemosynthetic bacterial assemblage at vents
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– Autotrophs use O2 to oxidize H2S, fix CO2
– S and carbohydrates produced |
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• Stable isotope data suggests
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more than one carbon fixation pathway at vents and that carbon not from photosynthesis
δ13C of suspension-feeding vent clams = -32.6, Riftia = -11 and non-vent benthos = -8 |
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Cold seeps
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Methane oxidation pathway (coupled with sulfate reduction) is useddd by bacteria at seeps
-H2s produced and may be used. Seeps are cold and may be found in very shallow water |
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How does Riftia provide the needed raw materials for its symbiotic bacteria?
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• Hemoglobin binds O2 and a protein binds sulfide in the blood in the red plume
• Circulatory system delivers oxygen and sulfide to tissues • Internal, symbiotic bacteria reside in the trophosome and account for 60% of the total mass of the animal |
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What is a reef?
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• Massive deposit of CaCO3 (limestone) produced by algae, coral and other invertebrates
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reef Importance to humans
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• Reefs create harbors and protect mangroves and seagrass beds
• Significant fisheries • Aesthetic appeal and tourism • Biodiversity high and chemical ecology complex -potentially important pharmaceutical and consumer products await discovery |
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Reef-building (stony) corals
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Hermatypic or Scleractinian
• Corals limited to seas > 20o C isotherm -optimal 23-25 C • Light is necessary for photosynthesis • Water depth limited to 50-70 m with the majority < 25 m Compensation depth at 15-20% of surface light • Grow fastest at 35‰ but tolerate higher salinity better than lower |
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• Non-reef building corals
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(ahermatypic or soft corals) are found worldwide, but are mostly solitary
-deep water soft corals are more prominent than soft |
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• Growth/shape of corals varies
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– massive, branching, foliose or laminar
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Planula larvae
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• A ciliated ball of cells with variable dispersal (perhaps days) before settlement and metamorphosis to a polyp
• Larval settlement may require coralline algae •Time to sexual maturation is relatively long (7-10 y) |
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Reef builders include
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• Corals, sponges, erect coralline algae (a type of red algae that resists grazing due to heavy calcification) and large molluscs precipitate massive amounts of calcium carbonate
• Encrusting algae in crevices cement the reef |
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Acanthaster planci
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Crown-of-thorns sea star
• Predator that feeds by digesting away the whole coral head after everting its stomach over it |
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Corals and reefs threatened by
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• Overfishing – destructive techniques including cyanide and explosives
• Eutrophication- nutrients make regulation or zooxanthellae difficult and they may grow too abundant and migrate • Global warming – corals live near their upper lethal limit for temperature |
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• Clupeids
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anchovies, herring, menhaden; #1 in tons
-shallow continental shelf fisher -phytoplankton feeders -large purse seines used -fish meal and fertilizer |
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• Gadoid
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cod, pollack, hake, #2 in tons
-bottom dwelling predators -continental shelf and shallow coastal waters -bottom trawls -used in fish burgers and artificial crabmeat |
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• Tuna and mackerels
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#4 in tons
– Top carnivores in oceanic food webs; 7-8 trophic levels below them – Active, cruising fishes that prey on clupeids – Purse-seine and long-line fishery – Human consumption – Dolphins may drown in seines although regulations have reduced mortality |
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• Crustaceans
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mostly estuarine-dependent shrimp
• -bottom trawls cause disturbance to benthos • -TEDS and by-catch |
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• Flatfishes
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flounder, halibut
-shallow water fishery -Hook and line |
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What fish are most
susceptible to overfishing? |
• Fish with long generation times, small clutches of eggs, and fewer spawning times are most susceptible to overfishing
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important sources of pollution
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• Nutrients, pesticides, hydrocarbons, metals and chlorinated hydrocarbons
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Poly-cyclic aromatic hydrocarbons (PAH)
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• < 20% of crude oil
• Toxic, mutagenic and carcinogenic • Contain C=C double bonds and from 1-6 benzene rings • Some are highly hydrophobic and long lasting in sediments, especially near contaminated harbors and industrial areas •At the cellular level, PAH are a narcotic that disrupts membrane function |
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cytochrome p450 enzymes
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metabolize hydrocarbons
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