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120 Cards in this Set
- Front
- Back
Primary producers are the foundation of?
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Food webs
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Each level in a food web is?
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A trophic level
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One basic food web is?
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Primary producers (phytoplankton) -> primary consumers (herbivorous plankton) -> secondary consumers (carnivorous zooplankton) -> tertiary consumers (carnivores)
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What is a trophic level?
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Composed of organisms that obtain their energy in a similar manner, it is an overly simplified compared to a food web
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Most food chains are?
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5 levels or less
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Trophic levels?
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Shows how energy flows among trophic levels
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Decomposers are also?
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A trophic level - feed on decaying organic material
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What is a food web?
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Summarizes trophic relationships in an ecosystem, takes all organisms of an ecosystem and who they feed on (Each organism)
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How does productivity influence available energy?
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Productivity can have a "bottom-up" effect
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What is this "bottom-up" effect?
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Effect higher trophic levels, Ex. seasonal increase in phytoplankton triggers increase in higher trophic levels, pulses throughout food web, when one organism population increases another will increase due to that increase
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In the Artic, productivity?
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Peak in summer
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In the North Atlantic, productivity?
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More vertical mixing in spring and fall so productivity blooms then
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In the North Pacific, productivity?
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Like North Atlantic
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In the Tropics, productivity?
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Blooms and pulses throughout
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Energy decreases with successive trophic levels depends two things?
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1.) Net primary production at base of the food chain
2.) Efficiency of energy transfers at each higher trophic level |
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What is the general rule for the transfer of energy?
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Only ~10% of energy stored in biomass in a given trophic level is converted to biomass at the next trophic level
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The transfer of energy?
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This loss is one reason why food chains are so short
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What is ecological efficiency (E)?
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Percent of energy transfer from one trophic level to the next
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What is the equation for ecological efficiency?
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E = Pt/Pt-1 (subscript)
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E = Pt/Pt-1?
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Pt is annual production at trophic at trophic level t
Pt-1 is annual production in preceding trophic level |
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Why are efficiencies so low?
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1.) We need to understand how organisms make use of their energy
2.) Assimilation depends on three factors |
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What is assimilation?
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Energy content of food digested and absorbed
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What three factors does assimilation depend on?
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1.) Ingested energy (I)
2.) Egestion energy (E) 3.) Respired energy (R) |
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What is ingested energy (I)?
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Energy content of food ingested
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What is egestion energy (E)?
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Energy content of indigestible materials defecated (hair, shell, cellulose)
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What is respired energy (R)?
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Energy consumer in cellular respiration
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So assimilation energy (G)?
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G=ingested-egested- respired energy
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Assimilated energy becomes?
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Part of biomass, which can be consumed by the next trophic level
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Number of trophical levels may be limited by?
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Ecological efficiency
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With average E of 10%, only?
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Only 0.01% will reach the fifth trophic level
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This is why?
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There are usually less than five levels in oceanic food chains
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Higher trophic levels?
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Have to eat and ingest more to get more energy
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The microbial loop is?
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An important part of food webs
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What is the microbial loop?
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Microbes (Bacteria and protozoa (Ex. single-celled protozoa)) that mediate the regeneration of nutrients into the food web
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What are a source of C (carbon, organic matter) for microbes?
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Plankton, metabolic by-products, and other organic materials (DOC)
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C is returned to the food web when?
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Microbes are ingested by pelagic species
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What is this food chain?
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DOC -> microbes -> protozoa -> herbivores
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Nutrient cycling?
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Nutrients can limit productivity and biomass in marine food webs
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Most limiting nutrients?
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Nitrate (NO3-), phosphate (PO4 3-), iron (Fe), and silicate (H2SiO4)
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What is iron used for?
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Used as a catalyst for silicon shells
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Why is nitrogen so important? (2)
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1.) Forms part of important biomolecules (amino acids, nucleic acids, chlorophyll, hemoglobin)
2.) Influence primary production and can limit how much biomass is produced |
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The N cycle is?
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Complex due to oxidized and reduced forms
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The ultimate source of N is?
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Atmospheric nitrogen (N2) (or molecular nitrogen)
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How much of the atmosphere is made up of nitrogen?
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78% of atmosphere
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So how does N get into sea water?
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1.) Nitrogen-fixing cyanobacteria convert N2 to ammonium ion, reduces form of ammonium can be dissolved into sea water
2.) Other bacteria convert ammonium into more usable forms of N (Ex. nitrate) that can be taken up by phytoplankton |
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Ammonium is not preferred?
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By primary producers
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Nitrogen cycling?
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atmospheric nitrogen (N2) -- nitrogen fixation (cyanobacteria) -> ammonium (NH4+) --- nitrification (nitrifying bacteria, oxidizing process) -> nitrite (NO2-) --- nitrification -> nitrate (NO3-)
Assimilation of nitrite and nitrate make organic N that then can be turned into ammonium by ammonification of ammonifying bacteria Nitrate can also undergo denitrification by denitrifying bacteria to turn into atmospheric nitrogen (N2) |
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C is not?
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Limiting (Nor a nutrient) but is essential for life
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C cycling involves?
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Chemical and biological processes
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More CO2 in seawater?
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It is readily dissolved, more marine problem then terrestrial
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CO2?
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Co2 inputs from atmosphere, respiration, mineralization, and dissolution of CaCO3
CO2 utilization of photosynthesis and formation of CaCO3 CO2 + H2O <=> H2CO3 (carbonic acid) <=> HCO3- (bicarbonate) (<=> CO3 2- (carbonate) + H+) + H+ CO3 2- + Ca2+ -> CaCo3 |
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What affect does increase in atmospheric CO2 have on marine life?
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Seawater pH will decrease (Tampa Bay - 7.8, Open ocean - 8.1)
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How will pH increase?
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More carbonic acid which breaks to excess H
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This process is called?
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Acidification
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Increased acidity will? (3)
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1.) Decrease the strength of calcifying skeletons of benthic invertebrates, coralline algae, and plankton
2.) Effects the integrity of coral reefs 3.) Reduce fertilization rates of marine animals |
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Seaweed are?
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NOT plants
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Plant morphology includes?
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Leaf, stem, and roots
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The leaf?
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Is a photosynthetic organ with stomata (pores), photosynthesis occurs here
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Stems?
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Supportive organ contains vascular tissue to conduct water (xylem) and sugars (phloem)
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Roots?
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Anchoring organ, absorbs dissolved nutrients in water from soil
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How are seaweeds different from plants? (5)
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1.) Kingdom Protista
2.) Colonial (Individual is known as thallus) 3.) Photosynthesis occurs throughout (all of thallus) 4.) Seawater is denser (Needs less support) 5.) Water and nutrients absorbed throughout (no need for complex structures, or a transferring system (no vascular tissue)) |
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Seaweed morphology?
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Frond, stipe, and holdfast
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Frond?
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Flattened part of stipe, most photosynthesis here, may have flotation structures
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Stipe?
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Connects holdfast and fronds; flexible
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Holdfast?
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Anchors organism to substrate
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Some seaweeds have?
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Pneumatocysts
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Pneumatocysts?
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Specialized structure that keeps thallus suspended
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Pneumatocysts are filled with?
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Gas, floats
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Which seaweeds have pneumatocysts?
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Kelps, Sargassum
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Seaweed classification? (3)
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1.) Chlorophyta - green seaweeds
2.) Phaeophyta - brown seaweeds 3.) Rhodophyta - red seaweeds |
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Cholorophyta? (3)
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1.) Chlorophyll a and b (accessory pigment)
2.) Ancestor to plants (terrestrial) 3.) Morphology ranges from leafy to filamentous (Highly branched) (Codium fragile was introduced to NE US and destroys oyster beds by smothering oysters) |
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Phaeophyta? (3)
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1.) Chlorophyll a and c, and fucoxanthin
2.) Morphology ranges from filamentous to the largest seaweeds 3.) Contain phycocolloids (gelatinous chemical) used in many products (medicine (pills), toothpaste, and human food) |
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Kelp is? (4)
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1.) Brown seaweeds
2.) Largest seaweeds (>15m) 3.) Visibility in kelp forests may be poor 4.) Thrive in cold (<20 degrees C) and nutrient-rich temperate waters |
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Nutrients are absorbed from the water column through?
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Fronds
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Fronds grow as much as?
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A half meter a day
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Kelp forest community? (5)
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1.) Kelp shrimp
2.) nudibranchs (sea slugs) 3.) Kelp crab 4.) Fishes (Rock fish, ect...) 5.) Coral |
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The sea otter (Enhydra lutris)? (5)
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1.) Common in kelp forests
2.) Preys on molluscs, sea urchins, fish 3.) Hunted for fun, almost driven to extinction 4.) Protected after 1911; population is increasing (California coast, Aleutian Islands of Alaska) 5.) Can alter structure of kelp forests |
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Sea otter - urchin - kelp interactions?
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Sea otters --> - sea urchins ---> kelp
Sea otters thus have a positive on kelp, by eating the urchins the sea otters benefit kelp (Sometime killer whales will keep sea otters in check) |
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Who discovered this interaction?
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James Estes and colleagues on the Aleutian Islands, Alaska
Where otters are abundant, sea urchins decrease, and kelp increase (Amchitka Island) There otters are scarce, sea urchins increase, and kelp decrease (Shemya Island) |
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Sea otters are?
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Keystone species
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What is a keystone species? (3)
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1.) Dramatically influence community structure
2.) Has a disproportionate impact on the community relative to abundance 3.) When removed causes the community to change significantly |
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In the Sargasso Sea?
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Sargassum (Brown macroalgae) floats in rafts that exceed hundreds of meters in diameter
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Where is the Sargasso Sea?
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1.) Located within the North Atlantic subtropical gyre (In the middle of the gyre)
2.) Circulation concentrates the algae inside the gyre, allowing it to aggregate in huge mats |
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Characteristics of Sargassum? (5)
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1.) Brown seaweed
2.) Lives in nutrient poor surface waters of the gyre 3.) Very slow growing 4.) Has a very long lifespan (Decades, centuries) 5.) Due to limited wind mixing, nutrients from decomposers and consumers are recycled back into sargassum growth |
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Sargassum supports many unique species of?
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Inverts and fishes (Sargassum frogfish and prawns)
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Rhodophyta? (4)
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1.) Red seaweeds
2.) Chlorophyll a and d, phycoerthrin, and phycocyanin 3.) Morphology ranges from filamentous to calcerous (Coralline algae -> Only in reds) 4.) Contains two types of phycocolloids: carregeenan (In cream cheese, ice cream, and toothpaste) and agar (for cultivating other) |
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Red coralline algae can be?
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1.) Non-articulated (encrusting)
2.) Articulating (branching) |
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Red coralline algae? (5)
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1.) Red seaweed
2.) Secrete calcium carbonate in cell walls 3.) Rocky shorelines and coral reefs 4.) Facilitate invertebrate settlement (Inverts graze epiphytic algae that would otherwise smother coralline algae) 5.) Contributes to coral reef building |
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What is another name for seagrass?
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Seagrass meadows
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What is seagrass? (4)
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1.) Submerged flowering parts in subtidal and lower intertidal soft-sediment habitats (Have little flowers sometimes)
2.) Plantae, angiosperms (Flowering plants) 3.) Descended from terrestrial plants 4.) 50 species worldwide in all regions |
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Important sea grass species?
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1.) Eel grass (Zostera sp.)
2.) Turtle grass (Thalassia) |
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Eel grass (Zostera sp.)?
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Temperate zones of North Atlantic, Europe, Asia, and Australia
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Turtle grass (Thalassia sp.)?
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Replaces Zostera south of the Carolinas, also on the east African coast
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The three local seagrass species?
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1.) Turtle grass species - Thalassia testudinum
2.) Shoal grass - Halodule wrightii 3.) Manatee grass - Syringodium filiforma |
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Local turtle grass species (Thalassia testudinum)?
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Blade is flat and wide, deeper waters
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Local shoal grass species (Halodule wrightii)?
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Blade is flat and narrow, shallower waters
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Local manatee grass (Syringodium filiforme)?
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Blade is round (like a manatee) (roll between fingers, if it rolls it is this), deepest waters of sea grasses
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Sea coverage in Tampa Bay?
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Has declined by more than 50%
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What was the reason for this decline? (4)
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1.) In the 1950's rapid growth of industrialization and development (Invention of the air conditioner)
2.) Not enough water treatment plants, raw sewage dumped into the Bay (Raw sewage makes excess nitrogen that stimulates phytoplankton growth and reduces clarity of water) 3.) Increase of dredge and fill development (man-made land) 4.) In 1980's finally more water processing plants and settling down |
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How do seagrasses grow?
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By vegetative growth by below ground rhizomes (below ground stems)
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How do seagrasses sexual reproduce?
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Pollination and seeds (embryo of sexual reproduction)
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How are these seeds dispersed and why is this important?
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Dispersal is dependent upon currents and is important for colonization of new habitats (asexual reproduction produces a rapid population in a local area)
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Seagrass maximum depth is dependent upon? (3)
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1.) Light penetration
2.) Water clarity or turbidity (affected by suspended sediments and phytoplankton) 3.) Epiphytic growth |
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Sea grass ephiphytes reduce?
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Reduce light availability and photosynthesis by 25% or more
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Excess nutrients in water column can stimulate?
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Ephiphytic growth
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How do seagrasses protect from ephiphytic growth?
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Some seagrasses secrete an antibiotic substance to reduce or protect from epiphytic growth
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How are seagrasses ecologically important? (5)
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1.) Increase sediment deposition and stabilization
2.)Increase water clarity (nutrient uptake, trapping suspended sediments) 3.) Contributes to estuarine productivity (carbon produced) 4.) Create substrate for ephiphytic organisms 5.) Enhances biodiversity by providing structure (ex. refuge for juveniles, fish, and inverts) |
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What are mangroves?
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Halophytic (salt-loving), woody trees and shrubs that are adapted to anoxic (low oxygen) and salty soils
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Where are mangrove distributed? (3)
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1.) 80 sp. worldwide
2.) Tropical environment (subtropical - tropical) 3.) South East Asia - Greatest diversity of mangroves (32 sp) |
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Why are mangroves are limited in distribution?
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Mangroves are temperature limited and do not occur in area where mean monthly temperatures are below 16 C
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For this reason, where mangroves distribution ends?
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Salt marshes usually occur
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How are mangroves adapted to waterlogged anoxic soils?
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1.) Aerial and shallow roots
2.) Aerenchyma tissue |
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The root systems of mangroves? (4)
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1.) Pnematophores (black), prop (red), and underground (white)
2.) Provides access to air 3.) Comprise up to 24% of aboveground biomass 4.) Have lenticels (tiny pores where oxygen can enter) |
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Aerenchyma tissue?
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1.) Allows oxygen to go throughout organism
2.) Honeycomb-like tissue that passively O2 from aboveground to belowground tissues |
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How are mangroves adapted to salty soils? (3)
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1.) Exclusion of salt and roots
2.) Elimination of access salt by secretion (salt glands on leaves) 3.) High concentration of organic solutes to minimize osmotic stress |
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How do mangrove exclude salt by their roots?
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Negative hydrostatic pressure keeps up to 90% of salts outs
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How do mangroves reproduce?
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Pollination and viviparious
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Mangrove pollination?
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Organisms visit plant and transport pollen to another part which then fertilizes the egg of another
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Viviparious? (4)
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1.) Bare live young
2.) Embryo seedling releases instead 3.) Dispersed by water 4,) Grow roots after hitting bottom or right spot |
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What is the advantage of viviparious reproduction?
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1.) Large propagules (seedlings) can survive harsh soil conditions
2.) Dispersed by water currents |