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121 Cards in this Set
- Front
- Back
euphotic zone
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aproximatley the first 200 m of the water column where there is sufficient sunlight for primary photosynthesis
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diatoms
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silicate shells
dominantly found in polar and temperate zones |
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dinoflagellates
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dominate in subtropical and tropical zones
some are bioluminescent or toxic |
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coccolithophores
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important in the trophics
composed of CaCO3 |
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primary productivity
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the amount of carbon fixed by photosynthesis per square meter of the ocean surface per year
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Gross PP and Net PP
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Gross is primary productivity before respiration is taken into account
Net is when it is taken into account |
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standing crop
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the biomass of individuals
g C/m2 |
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what is important about primary productivity
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foundation for occeanic food webs
major source of earth's free oxygen major effect on earth's carbon budget |
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what are the relative estimates of primary productivity on land vs in the sea
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46.2% sea
53/8% land |
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Compare the average residence time of C in plant biomass on land vs the sea
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land = 10 yrs large immobile
sea = 15 days small mobile |
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which biomes have the fastest rate of primary productivity
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aquatic-marine esp coral reefs
rain forests |
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what limits and controls PP
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lights and nutrients
prblm: high nutrients lower in water column, which means less light |
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biological pump
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carbon that is emitted into the atmosphere is absorbed by the ocean, or fixed by phytoplantkon and plants. The phytoplankton eventually die and sink to the bottom
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what form of light penetrates the farthest into the water column
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blue and green light
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compensation depth
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where the rate of photosynthesis = rate of respiration
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critical depth
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where the total photosynth is equal to total respiration
photosynth is larger after that point upward |
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what nutrients are limiting to phytop
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ammonium
nitrateiron silicon calcium phosphorus |
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what happens when the mixing depth exceeds the critical depth
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you get a phytoplankton bloom
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compare the richest sea water with the richest soil
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richest seawater: 0.00005% N(rich soil: 0.5% N)
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which do phytoplantkon respond to more enrichment by N or P?
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by N
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Does phytop rise constantly with increasing N
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no, eventually there is a peak
bell curve |
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what is the main limiting micronutrient
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iron
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explain productivity in tropical regions
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stable and will increase with upwelling bc nutrient limited
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explain producrivity in temperature regions
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spring and fall bloom
spring bloom occurs because of upwelling and light overlapping fall bloom occurs bc of winds kicking up and there sitll being enough light aroiundq |
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explain polar productivity
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occurs when sunlight comes out bc no nutrient limited
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what direction does the wind need to blow in to get upwelling in oregon
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from the north
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where does the most primary productivity occur
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on the coastal shelf
large euphotic zone higher nutrients |
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what is the paradox of plankton
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that numerous species of plantkon can exists without competetive exclusion even though they eat the same resource
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what is the hypoth backing up the paradox of plankton
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the gradual change hytpoth
each species is a dominant under different seasonal conditions |
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secondary productivity
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rate of change of consumer (heterotroph) biomass from growth and reproduction
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what is the global positive relationship for secondary productivity?
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phytoplankton being limited by light and nutrients is correlated with zooplankton's limitation by phytoplankton and carnivores above them in the trophic level.
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what is the global positive relationship for secondary productivity?
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areas where there is high productivity from upwelling leads to higher biomass of zooplankton
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what is the local negative relationship for secondary productivity?
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phytoplankton and zooplankton population peaks are not directly aligned. Phytoplankton have shorter generation times than zooplankton. Zooplankton take longer to respond to a phytoplankton bloom
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why are there more tropic levels in the sea than on land
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because there is high ecological efficiency bc of smaller organisms and there is few size constraints on predators
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ontogenetic diet shifts
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animcals consume different foods as they grow
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omnivory
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anicamls consume more than one trophic level
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what category does mixotrophy fit under?
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omnivory
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give an ex of a mixotroph
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dinoflagellates
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explain the microbial loop
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it is a cycle where dissolved organic carbon is recycled into the food web.
bacteria and really small plankton eat DOC which are then eaten by protozoans which is then consumed by zooplankton. |
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approximately what percent of PP is recycled back into the food web from the microbial loop
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20%
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give 3 examples of why pelagic food webs are more complex than on land
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there are ontogenetic diet shifts (as an org grows it changes what it eats in the food chain)
omnivory and mixotrophy microbial loop |
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ecological efficiency
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biomass stored in a consumer trophic level divided by the energy stored in the consumed trophic level
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Of the three cycles listed, which are fast and which are slow: C, N, P
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P is slow
C and N are fast |
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What organisms make up the upper innertidal in the Pac US
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periwinkles, snails, algae
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what organisms compose the middle innertidal in the Pac US
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mussels, barnacles, seaweeds
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what organisms make up the lower innertidal in Pac Us
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sea weeds and surf grass
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What organsism make up the upper, middle, and lower inner tidal of Altantic
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Upper - lichens and encrusting algae
Middle, barnacles and rockweeds, mussles lower- irish moss extreme low - seaweed |
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What are the 3 alternative hypotheses for what causes zonation
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physical limitations
biotic limitations settlement patterns |
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explain the physical limitations hypothesis
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lower limit is set by too much immersion in the water (drowning)
upper limit set by too much dessication--> typically what sets the liimitation wave shock can also determine it as well |
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explain the biotic limitations hypothesis
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competition and predation
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use the barancle ex to explain biotic limitiations
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little gray and large rock barnacles both have juvenilles that settle in the same place. The little gray has a smaller range due to dessication and competition by the larger barnacles.
the larger barnacles are limited by predation from whelks |
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what happens to mussels when they are no sea stars present
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they take over the inner tidal system
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explain the settlement pattern hypothesis
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depending on where larvae land will dictate their range
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explain how the 3 hypothesis of zonation overlap
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physical limitiations typically let the upper limit through dessication and wave shock
lower limit is usually set by biotic limitations of competition and predation in calm bays, different species will settle in different areas, creating zonation |
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what structures a community
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the number of trophic levels
number of species distribution and abundance of species |
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what are the 3 overlapping hypothesis on what structures a community
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1) the top down model- consumers have the strongest effect bc they are highly efficient
2) bottom up model- nutrients and primary productivity have a strong effect 3) environmental stress/disturbance can effect the level of strength of top and bottom effects |
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stress
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causes organism to devote energy to cost, but does not result in death
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disturbance
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causes mortality
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keystone species
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species that has an effect on the community that is disproportionate to its abundance
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explain the top down model
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keystone species and dominant predators end up creating space which allows for more individuals to enter the community
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explain why the graph of keystone snail population vs algal species density is a bell curve
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when density is low, the dominant seaweed outcompetes. When there is intermediate amount of predators, the dominant species is kept in check, allowing for colonization by other species. However, at high snail density then there is not enough food, so they eat any seaweed
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explain the relationship between a keystone species that prefers the subordinate species
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linearly negative
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predation decreases prey diversity hypothesis
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prey diversity increases with increasing predation
this is more rare but occurs when the subordinate prey is preferred |
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intermediate predation hypothesis
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follows the snail and algal species ex where an intermediate amount of predation open up space and decreasing competition
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explain indirect effects of top down models and how they affect alternate stable states
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In New England, crabs which snails that eat a certain type of seaweed keep irish moss outcompeted. However, if a disturbance occurs and wipes out the dominant seaweed, then the crabs are exposed for predation, then the snails keep eating, leading to irish moss being dominant
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bottom up model
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when nutrients are low, plants are low, which cannot support upper trophic levels.
When nutrients are high then predatores and plants are high with herbivores being grazed |
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What is an oregon EX of a bottom up model
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Boiler bay --> low phyto p causes a algae dominant system
Strawberry hill --> high phytoplankton supports upper trophic levesl included mussels which eat algae |
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are consumers or predators more susceptible to stress?
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consumers because they are more mobile
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in a high stress system would consumers or prey be dominant? in a low stress system?
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Consumers -- dominant in low stress
high stress- prey |
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what is the disturbance model
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physical disturbances wipe out populations to where competetive exclusion no longer occurs, increasing species diversity
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what are conditions to the disturbance model
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the model depends on the way the community was structured before the disturbance and how species diversity changes during succession
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what is the intermediate disturbance hypothesis
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that during low disturbance, there is still high competition
during intermediate disturbance some of the population is wiped out to great a mid-succession stage, opening space for more individuals high disturbance wipes out all diversity |
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what is one final factor to consider in community structure
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chance settlement events
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what are characteristics of kelp forests
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temperate h20 that has moderate water motion and clarity
found between 30-60 degrees kelp-large brown seaweed |
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characteristics of kelp
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apical meristem at bulbs
leaf like stipes with blades holdfast that is not a root complex life cycles that involve betwen a sporophyte and a gametophyte |
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is kelp consumed?
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not really, it used to be by stellar sea cows
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biogenic habitat
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created by life
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explain the relationship between kelp and urchins
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when there is drifting kelp the urchins stay in their holes
When the kelp popul decreases urchins come out of their holes to search for food and are exposed |
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explain the alternate stable states of a kelp forest
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during an el nino there servere storms, low nutrients, and warm temperatures. This causes a decrease in kelp recruitment. Combined with high grazing by urchins (who came out of their holes), it leads to a low standing crop of kelp
The other state is when nutrients are high and waters are cooler. Kelp are healthy, with high recruitment. Drift kelp is present to keep urchins happy which ultimately leads to a good standing crop |
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how do sea otters affect kelp forests
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they are keystone species, keeping urchins in check
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When otters are present what state is favored
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the one where kelp is dominant
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what is happening with orcas and sea otters
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overfishing by humans decreases fish for seals, causing population collapse. Seals are the main food for orcas, but they have switche instead to eating otters
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what happens when orcas eat otters
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urchins become dominant and eat the kelp
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what makes up a coral
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they are organisms that have a symbiotic relationship with zooxanthellae. they are polyp organisms that secrete a calcium carbonate skeleton
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how do coral grow
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asexual budding
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when do coral reproduce
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1-2 nights a year
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what are the methods of reproduction in coral
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sexual- with separate sexes of simultaneous hermaphrodites
asexual fragmentation |
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sexual reproduction involves what
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broadcast spawning
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are corals autotrophs or heterotrophs
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autotrophs at day during the sunlight
heterotrophs at night when there is no sunlight |
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zooxanthellae
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dinoflagellates that supply carbohydrates to coral
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what causes high porosity in coral reefs and why is it important?
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the high porosity occurs from many different structures occurring in the reef
it allows for sediments to be trapped that contain nutrients |
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how much of the earth's surface is covered by coral reefs
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1 percent
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What are conditions for coral to live in
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higher or equal to 20 degrees Cel
less than 60 m deep ocean salinity of 34-35 ppm |
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what are the 3 times of coral reefs
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fringing
atoll barrier reef |
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what is the order of reef succession
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fringing reef
barrier atoll |
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what are barrier reef lagoons important
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they are nursey habitats for coral reef invertabrates and fishes
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how much mangroves and lagoonal nurseries have been lost
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50%
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coral reefs are what percent of the world's marine food catch
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10%
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what is the primary productivity in coral reefs? how does that compare to the surrounding ocean
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1500-5000 g C / m2/ yr
compared to 18-50 C/m2/yr |
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why are coral reefs the highest of marine primary productivity?
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efficient nutrient trapping: a lot of planktivores, blue-green algae fix nitrogen, complex reef structue traps detritus and nutrients
efficient nutrient cycling: rapid consumption and recycling of nutrient detritus, complex food web with high predation two sources of benthic photosynthesis: benthic algae supplement coral and there is a stable abiotic environment with year round light |
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guilds
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organisms grouped by what they eat
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what is the estimated amount of species in a coral reef
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9 million species
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how many coral species
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1000
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how many fish in coral reefs
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10000
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how many invertebrate and seaweed species
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100,000
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how do so many species of coral coexist
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because of the intermediate disturbance hypothesis
Medium, moderately frequent, and medium time after a disturbance has occured is when diversity is at its highest |
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how do so many species coexist in coral reefs
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intermediate predation hypothesis
specialized predation allows for individuals to enter the reef |
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where to cryptofaunal communities exist in coral reefs
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on the undersides of coral plates
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what is the competition hypothesis of fishes in coral reefs
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a stable environment leads to high larval recruitment, large population sizes, and interspecific competition. This will cause resource partioning which will lead to coexistence
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what is the recruitment limitation hypothesis
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low larval settlement causes small population sizes, leading to little or no competiton, allowing for coexistence
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what is the predation hypothesis of fish that allows for many species to live together
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high larval settlement leaves to high predation on new recruits, causing a small population, low predation, and coexistence
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How do corals benefit humans
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aesthetics and recreation
coastal protection building materials jewelry and curios tropical aquariums fisheries new medicines |
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what biome has the most economic value to humans per unit area
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coral reefs
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how many species have already been lost on coral reefs
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100,000
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How many coral reefs have already been lost
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19%
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how many reefs were lost in the 1998 bleaching event and why
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warmest year on record
9% lost |
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What are threats to coral reefs
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siltation
eutrophication overfishing: tourism trade, destructive methods, live reef fish trade, indirect effects |
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what are two alternate stable states for reefs
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reduced herbivore grazing leads to algal cover, decrease coral recruiment, reduced coral, reduced structural complexity, low fish recruitment, which leads to reduced heribovre grazing
the other is where there is intense grazing that leads to reduced algae cover, more coral recruitment, more coral cover, more structural complexity, more fish recruitment, more grazing |
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what are the cascading effects of lionfish
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overfishing and lionfish predation reduce herbivores which increase algae and thereby reduce coral
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how does ocean warming hurt coral
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increased storms
bleaching overgrown by seaweed when bleached and unable to recover increasing emergent diseases |
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white pox disease
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hurting corals and originates from human gut
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