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156 Cards in this Set
- Front
- Back
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why is there low biodiversity in estuaries
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young communities
stressful abiotic environment high turbidity low habitat complexity |
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how long do estuaries last for
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about 10,000 yrs before they turn into sediment
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what are two kinds of estuarine vegetation
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temperate salt marshes
tropical mangroves |
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what are salt marshes dominated by
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emergent grasses
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what are tropical mangroves dominated by
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emergent trees
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salt marsh vegetation and sediment
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the vegetation traps sediment allowing for high nutrient retention
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salt marshes and coastal erosion
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prevents coastal erosion
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where does most of the primary productivity of salt marshes come from?
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grasses, then seaweeds, phytoplankton
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grasses avg PP
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1500 g C /m2/yr
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seaweeds avg PP
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500 g C/m2/yr
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phytoplankton avg PP
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low because there is little light available
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what sets the upper limit of estuaries
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biotic factors-competition
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what sets the lower limit of estuaries
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abiotic factors (salinity)
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why are estuarine zonation factors backwards from the rocky intertidal
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because it is the terrestrial environment invading the marine world rather than the other way around
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explain competition between dominant grasses in estuarine environments by using the ex: rush and cordgrass
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rush is the dominant competitor. More on land that it is in the low zone bc it is intolerant of salt water. It excludes cordgrass from the high zone.
Cordgrass is tolerant of salt water so it exists in the low zone which provides it a competetive refuge. |
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what is the dominant food web in the intertidal mud flats
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the detritus based food web because not a lot of the plants get eaten, so they become detritus
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give the outline of the detritus based food web
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primary productivity occurs mostly in grasses which are high in salt and fiber, but low in nutrients
therefore, they aren't eaten very much (10% is eaten) Decomposed grasses are eaten by decomposers, who are eaten by invertebrates The invertebrates are eaten by fishes and birds |
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epifauna
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live on the seafloor
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infauna
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live in the sediments
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meiofauna
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small animals that live between sand grains
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what are two types of feeding on the sea bottom floor
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suspension feeding and deposit feeding
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suspension feeding
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where individuals feed on POM floating in the water
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deposit feeding
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where individuals feed on POM on the bottom of the ocean floor
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what often determines if an individual is a deposit or suspension feeder
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the turbulence of the water. If it is, then individuals can be suspension feeders because larger particles are still present in the water column. If it is less turbulent, then deposit feeding is prefered because only smaller particles are in the water column
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what causes the vertical zonation of infauna
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individuals in the shallows have mechanisms against predation by birds, fish, etc.
those that are lower in the sediment column can withstand harsher environments |
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subtidal channels are
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always underwater
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what is the dominant food web of subtidal channels
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detritus based
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how do juvenille fish move in estuaries
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the follow the currents caused by freshwater and saltwater movement in the estuary. Allows for energy conservation
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What are the benefits of estuaries to humans
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14% of marine pp
90% of riv deposition food nursery habitat bird habitat coastal protection clean water |
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how quickly are estuaries disappearing
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50% in PNW gone
90% in California are gone filled for coastal development |
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What is the salinity range of brackish water
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around 10 ppm
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what is the salinity of the ocean
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around 35 ppm
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what is the avg salinity in the estuary betwen low and high tide
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10 to 30 ppm
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what percent of the ocean is deepr than 1000 m?
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90%
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what is the mean depth of the sea?
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4000m
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what is the maximum depth of the depth sea
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11,000m
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the abyssal plain of the ocean covers how much of the Earth
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greater than 50% of the ocean
exact is 62.2% |
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By volume the deep ocean makes up how much of the ocean
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78.5%
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what are characteristics of the abiotic environment of the deep sea
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low and stable in temperature *(2-5 degrees C)
high and stable in oxygen content high pressure (1 atm per 10 m in depth) no sunlight below 1000 m sparse food |
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how is oxygen inputed to the deep ocean
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thermohaline circulation
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oxygen minimum layer
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occurs around 500m
in this layer photosynthetic organisms are being recycled, which uses the available oxygen in the water organisms in this layer must be adapted to low oxygen levels affects sea mounts |
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what percentage of the epipelagic zone ends up making it to the deep ocean
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1%
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what is the dominant food web at the bottom of the ocean
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detritus based food web
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what is the dominant body type in the benthos
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small
low in density |
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what is the dominant mode of feeding in the deep benthos
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deposit feeders
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what is the dominant type of organism found in the deep ocean
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echinoderms
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What geographic portion of the bottom of the ocean floor has the highest species diversity
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continental rise
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explain the bathymetric pattern for diversity
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shallow depths have high 2nd producuctivity which leads to high population densities, increased competition and predation, leading to a low species diversity
at intermediate depths like the continental rise, there is medium seconday productivity leading to moderate densities and weak biotic exclusions in deep water there i9s low 2nd productivity, low densities, and mroe extinctions bc there is not enough food to sustain |
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where are hydrothermal vents found
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at seafloor spreading
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what is the dominant food source for primary productivity on hydrothermal vents
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hydrogen sulfide
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endemism
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species found in a given habitat and no where else in the world
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How much carbon is fixed through chemosynthetic primary production
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100 g C /m2/yr
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how long to hydrothermal vents last locally?
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10 yrs because the sea floor moves
they will last 5 to 10K years regionally |
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how do carcasses influence hydrothermal vents
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they are stepping stones to colonizing vents
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mesopelagic zone
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200-1000 m in the water column
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characteristics of the mesopelagic zone
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decreasing light and productivity with increasing depth
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what are characteristics of organisms in the mesopelagic zone
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larger eyes and smaller bodies with increasing depth
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what are two eating strategies for organisms in the mesopelagic zone
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active foragers: usually migrate vertically
non-migrators: they are usually sit and wait predators |
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diel vertical migration
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organisms that live deeper in the water column will go up into the photic zone at night to eat
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what are cues for organisms in diel vertical migration
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the deep scattering layer, using ambient light
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What are the 4 hypotheses for why diel vertical migration occurs
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1- predator avoidance
2- energy conservation, the water is warm at high in the shallows bc it has been heated 3-fish stay with prey as they migrate 4-horizontal transport for inverts to maintain position in a productive area |
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bathypelagic zone
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greater than 1000m
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why are photophores used in the bathypelagic zone
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avoid predators
startle predators find prey attract prey attract mates species recognition |
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what are common adaptations in bathypelagic organisms
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small body with high water content
large mouth and distendable gut to eat large prey fine gill rankers to eat small organisms |
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Sparse food and low population sizes leads to what adaptations to find mates?
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simultaneous hermaphroditism
parasitic malesin deepsea anglerfishes |
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polar oceans refer to
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the arctic and southern ocean
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what is special about the southern ocean
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it can circumnavigate the whole bottom of the S. hemisphere without running into a land mass
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features of the arctic ocean
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land locked with low upwelling and is ice covered ocean
low producitivity 1-100 g C /m2/yr |
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features of the southern ocean
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ice stays on land and there is seasonal ice on the ocean
pulses of productivity 40-260 g C/m2/yr |
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why is the antarctic more diverse than the arctic
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because it is more productive
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compare the number of invertebrates in the arctic vs soutern oceans
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AR: 1300
SO: 3100 |
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what kind of food web does the arctic have?
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a simple food web because there is low diversity
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how will the arctic ecosystem change as global warming inceases in intesity
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melting of ice will decrease polar bear populations
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why is the southern ocean so productive
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because wather is being pushed away by the coriolsis fors and water is upwelled in its place
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what is a consequence of the high PP in the SO
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high species diversity
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what is the antartic convergence
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the separation between upwelled and not upwelled water and defines the SO
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what is the PP of the SO limited by
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light
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What wind is responsible for pushing the water that results in so much upwelling in the SO
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west wind drift
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what else is responsible for nutrients being brought up in the SO
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thermohaline circulation
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what nutrient limits PP in SO
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iron
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what is the main consumer of phytoplankton
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krill
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how efficient are krill
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30%
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What do krill eat during the winter time
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ice algae
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what plays the most central role to the food chain other than phytoplankton in the SO
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krill
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give a break down of who eats krill
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17 % by squid
21% by fish 11% by penguins 11% by seals |
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how is it that so many seals live in the southern ocean
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resource partioning of what they consume
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what is the largest consumer of krill
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baleen whales
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what is the largest animal on earth
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blue whale
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when did the international moratorium on commercial whaling occur
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in 1985
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when whales were overharvested what happened to the extra krill that had not yet been consumed
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it increased minke whales and increased penguins too
more squid --> more king peng more fur seals --> more carrion --> more petrels |
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what is a result of global warming in the southern ocean
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melting of ice shelves, leading to liss ice algae, and less winter food for krill
inedible salps wil replace krill |
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Relate the proportion of PP to warm blooded predators @ poles
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it is the largest compared to lower latitudes
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compare the depth of the northern vs soutern ocean
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N is much more shallow than the southern ocean
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Prokaryotes and eukaryotes in the polar oceans
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almost all major varieties are represented showing their ability to adapt to cooler water
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two major things that sea ice does to effect pelagic polar ecosystems
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sea ice causes reduced attenuation of light in the water column. Melting sea ice releases iron stored in the ice which is a limiting nutrient for PP. algal cells are also released from the ice as well
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is the arctic nutrient or light limited
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light
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hat nutrient limits production in the Bering Sea
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iron
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how are the bering and barents sea the same
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they both have high populations of marine life and large stocks of fish
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what is the limiting nutrient in the soutern ocean
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iron
it is limiting because sediment is not trapped in the ice as it forms like in the arctic |
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where is productivity limited to in the southern ocean
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the continental margin where upwelling is occuring
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what is a unique source of iron in the southern ocean
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dust settling with snow
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what plays an integral role in the recycling of nutrients and retention of them in the southern ocean
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fecal matter
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what percentage of the us fisheries are overfished
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9%
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what percentage of the us fisheries are not overfished
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15%
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what percentage of the us fisheries have not been identified as overfished or not
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76%
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Explain the distribution of the status of Oregon's fisheries
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2 species are depleted
6 OK 35 unknown |
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when does overfishing occur
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when fishing mortality rate is greater than the fish reproduction and growth rate
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what is the difference between overfishing and overfished
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overfishing = high fishing mortality
overfished = low abundance |
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what is the US definition of overfished
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when the population is reduced to less the 25% of unfished biomass
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what stock percentage is considered the rebulding point for depleted fisheries
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40%
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what is the economic value of marine biodiversity
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over 60%
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What are threats to marine biodiversity
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overfishing
habitat destruction invasivespecies pollution ocean warming and acidification |
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name the recent extinctions in the sea
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2 algae
3 cnidarians 5 snails 3 fishes 5 birds 3 mammals (sea cow, monk seal, seal mink) |
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how many species have been lost on coral reefs
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300,000 to 400,000
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what is the problem with marine conservation that it currently faces
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It does not have the information it needs in order to conserve species
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what two things account for the largest proportion of marine extinction
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overfishing and habitat destruction
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give a breakdown of the status of the world's fisheries
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52% fully exploited
24% over exploited 24% moderately or under exploited |
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how does overfishing impacts humans
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means less food for humans per catch
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how does overfishing affect the fish
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it makes smaller species more dominant
maturity @ a young age nontarget species become dominant alters trophic cascades (changes what is dominant) |
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what are the proximate causes of overfishing
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too may fisherman with too many boast, too much gear, and too much technology
bycatch habitat destruction scientific uncertainty |
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what causes habitat destruction
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dredging, towing of nets, bottom trawling,
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what are the ultimate causes of overfishing
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human population explotion
tragedy of the commons (commons =ev owns fish tradgedy = if i don't catch someone else wiill) |
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maximum sustainable yield
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most fish you can take without depleting populations
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when does maxiumum profit occur
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before maximum sustainable yield but this only occurs when the tragedy of the commons is not occurring
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open access equillibruim
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where cost equals gross profit
this occurs when fish are overfished |
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how do subsidies affect overfishing
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they encourage it because it allows fishing to be maintained at the same level
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ecosystem based management is based on what principle
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the precautionary approach: 1st priority is to do no harm to ecosystem
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adaptive management cycle
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learn by doing and continual evaluation
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how does ecosystem based management view MSY
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it sees that the maximum is constantly changing and therefore never sustainable
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what is the marine reserve that oregon has
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whale cove
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what is the main idea behind marine reserves
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that big old fat female fish will be protected, increasing offspring. offspring will then spill over into fishable waters.
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what is aquaculture not sustainable
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marine fish feed the aquacultured fish
habitat destructino invasive species disease genetic csts |
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why does a dead zone occur
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a phytoplankton bloom occurs and there isn't enough zooplankton to consume it. as the dead pp fall in the column respiration depletes the o2 from the water column
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what is anoxic conditions
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0 mg O2/liter
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what causes oregon's dead zone
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upwelling brings up O2 depleted water with lots of nutrients from the oxygen minimum layer (around 500 m
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biomagnification
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where fat soluable pollutants that are not excreted will accumulate in the body. This includes heavy metals and halogenated chemicals
become more concentrated up the foodchain |
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where does mercury poisoining come from
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burning coal
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what are two sources of invasive species
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intentional and unintentional
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what are intentional sources of invasive species
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sportfishing and aquaculture
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what are uninentional sources of invasive species
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from the hulls of ships and ballast water
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what has happened to the native mussel in california
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it has been replaced by the invasive mussell
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mitten crab
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invasive species in california that is a voracious predator, clogs fishing nets, bio-eroders, etc
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how many invasive species are there in san fran
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250
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what are common invasive species in pcnw
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jap eelgrass
new zealand pill bug |
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what is bad about invasive species
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outcompete
overconsume alter habitats |
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def of pollution
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overloading an ecosystem w/ chemicals
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what is the top sources of pollution
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44 coas runof
33 atm dept 12 ship spill 10 legal dump 1 offshore mining |
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what are other sources of pollution
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heat
sound ozone depletion |
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runoff effect
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ag stuff ends up feeding blooms which leads to dead zones
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why does the east coast have more dead zones than the west coast
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because it has a passive margin and therefore has more rivers
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what animal group was killed off the most by exxon valdez oil spill
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400,000 seabirds
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what are 3 key fats to ocean warming
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1. oceans are warming
2. sea level is rising 3. ocean is acidifying |
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why is ocean acidification occuring
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1. co2 is a greenhouse gas
2. the present levels are higher than they have been in over 800,000 yrs 3. extra co2 is from deforestation and coal burning 4. co2 dissolved in seawater forms carbonic acid |
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what are some consequences to ocean acidification
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loss of species that contain caco3 in their skeleton
shift in species trophic cascade |
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what are some consequences of ocean warming
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melting ice
rising sea levels diseases coral bleaching shifitng species distributions methane from sea floor |
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tipping point
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point where postive feedback loops occur with negative effects
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