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24 Cards in this Set

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Hydrothermal vents
Occur at
ocean-spreading centers worldwide
What are hydrothermal vents
• Fissures or chimneys in ocean crust where geothermally heated water released
-undersea hot sprigs
• Dense chemosynthetic bacterial assemblage at vents
– Autotrophs use O2 to oxidize H2S, fix CO2
– S and carbohydrates produced
• Stable isotope data suggests
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
Cold seeps
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
How does Riftia provide the needed raw materials for its symbiotic bacteria?
• 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
What is a reef?
• Massive deposit of CaCO3 (limestone) produced by algae, coral and other invertebrates
reef Importance to humans
• 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
Reef-building (stony) corals
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
• Non-reef building corals
(ahermatypic or soft corals) are found worldwide, but are mostly solitary
-deep water soft corals are more prominent than soft
• Growth/shape of corals varies
– massive, branching, foliose or laminar
Planula larvae
• 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)
Reef builders include
• 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
Acanthaster planci
Crown-of-thorns sea star
• Predator that feeds by digesting away the whole coral head after everting its stomach over it
Corals and reefs threatened by
• 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
• Clupeids
anchovies, herring, menhaden; #1 in tons
-shallow continental shelf fisher
-phytoplankton feeders
-large purse seines used
-fish meal and fertilizer
• Gadoid
cod, pollack, hake, #2 in tons
-bottom dwelling predators
-continental shelf and shallow coastal waters
-bottom trawls
-used in fish burgers and artificial crabmeat
• Tuna and mackerels
#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
• Crustaceans
mostly estuarine-dependent shrimp
• -bottom trawls cause disturbance to benthos
• -TEDS and by-catch
• Flatfishes
flounder, halibut
-shallow water fishery
-Hook and line
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
important sources of pollution
• Nutrients, pesticides, hydrocarbons, metals and chlorinated hydrocarbons
Poly-cyclic aromatic hydrocarbons (PAH)
• < 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
cytochrome p450 enzymes
metabolize hydrocarbons