● 1% of primary production at ocean’s surface reaches bottom in deep sea● 3 ways food produced at ocean’s surface reaches deep ocean:○ marine snow○ sinking of large carcasses○ vertical migration● Filter feeders are NOT common in the deep sea○ most deep-sea organisms are deposit feeders because most available food is food that sinks from above● pressure: 1 atm for every 10 meters● Oxygen Minimum Zones are important features of marine environment○ How are OMZs coupled to processes in the overlying water column■ no primary production in the area so it depends heavily on primary production sinking down from the surface○ What is a typical depth range for an OMZ in the open ocean■ 200-750 m● Example of strategy used by bioluminescent deep sea organisms to make them better predators○ anglerfish lures● Avoid being eaten- counterillumination● Names of depth zones● Mesopelagic- fish with tubular eyes● Hydrothermal vents: hydrogen sulfide● Cold seeps: methane● Hydrothermal vents are typically associated with tectonic features of sea floor spreading centers● One theory for the dispersion of hydrothermal vent organisms to new vent sites involved stepping stone microhabitats○ What was basis for microhabitats?■ Whale carcasses/bones allowed tube worms to persist between vent communities○ Why was this theory discounted?■ no species overlap- the DNA of the worms on the “stones” did not match species at vents etc● What characteristics of vestimentiferan worms like Riftia might you expect in order for them to successfully find and colonize new hydrothermal vent sites?○ Eggs- many eggs○ Larval biology- Lecitotrophic- short larval stage because not enough food to support prolonged existence in plankton● Explain how foodweb interactions between killer wales, sea otters, sea urchins, and kelpcan lead to alternative stable states of a marine ecosystem and briefly describe the 2 different endpoints.○ Either sea urchins eat everything or HUGE kelp forests● Grand prey collapse- the killer whales’ main prey would be so depleted that they must find a new source of food○ why is this theory unlikely to be correct?○ what alternative hypothesis might explain the phenomenon (changing food preferences)?● 3 mechanisms that cause surface waters in coastal zones to be enriched in nutrients○ upwelling○ land runoff○ benthic regeneration● How does the presence of a bottom affect primary production in shallow water ecosystems? (3 factors)○ allows light penetration all the way to the bottom● Size of meiofauna = <0.5 mm● Kelps are brown algae● Laminaria and Nereocystis are genera of kelps● Kelps grow best in habitats that feature high nutrients and strong currents● Kelps are grazed by sea urchins● Seagrasses are true plants● An important genus of seagrass is Zostera● How do seagrasses affect sediment accumulation?○ Seagrasses increase sediment accumulation- their roots help prevent erosion and the grass itself traps sediment suspended in the water.● Massive seagrass dieoffs possibly due to○ infection by pathogenic fungi○ effects of eutrophication○ overfishing○ suspended sediment from accelerated erosion in the watershed● red mangrove = rhizophora mangle● Main environmental factor that limits the northwards expansion of mangroves from Florida into Georgia: water temperature- too cool in Georgia● Mangrove seeds are dispersed by drifting in the ocean● Pneumatophores are adaptations used by mangroves to conduct oxygen to their roots● Pneumatophores are NOT characteristic of all mangroves● How are the distributions of mangrove & coral reef ecosystems linked?○ Physiological: both in warmer coastal waters○ Functional: both act as barriers between the sea and the mainland● Zooxanthellae are dinoflagellates● Factors that limit the distributions of typical reef building corals:○ light○ water temperature○ nutrient concentrations○ salinity● Explain the phenomenon of coral bleaching:○ dying out of coral on a reef, ocean acidification/increased CO2 is partially to blame○ loss of zooxanthellae● Coral animals are in the phylum Cnidaria● Explain how the relationship between corals and their symbionts works: ○ the coral supplies:○ the symbiont supplies:● What are the characteristics of sea level changes associated with each of the following tidal cycle classifications?○ diurnal: 1 high tide & 1 low tide per day, generall same height each time○ mixed semidiurnal: 2 HT & 2 LT per day, at varying heights● What other factor besides the sun and the moon affects the tides experienced at a given location on the coast?○ bathymetry & geography○ wind & currents● Three physical factors that affect the vertical distributions of intertidal organisms:○ temperature○ dessication○ water motion● The diversity of intertidal communities typically INCREASES along a transect from meanhigh water to mean low water● What are 3 general strategies that organisms use for dealing with exposure to our world during low tide○ moving away from exposure○ sealing self off from exposure○ tolerating exposure● 3 major general classes of biological factors that are responsible for distributions of organisms in rocky intertidal communities:○ predation/herbivory○ competition○ larval recruitment● What are the characteristics of an organism fitting Paine’s definition of of a keystone species or predator?○ community structure: has a disproportionate effect on the ecosystem○ energy flow: not a big energy sink● 3 kinds of interactions between first organism and succeeding organism: what are they and how do they work?○ Inhibition- initial colonizers inhibit further colonization○ Tolerance- initial colonizers do not affect later colonizers but over time species most tolerant of local conditions prevail○ Facilitation- initial colonizers facilitate success of later species● Physical dynamics that lead to formation of a beach require waves and a source of unconsolidated sediment● Organisms that live on beaches are usually highly mobile and equipped with tough cuticles● The activity of many organisms is tied closely to various natural cycles. give an example of this behavior and how it might have evolved○ crabs that only come out at night○ predators may be less abundant at other times or prey is more abundant● Barrier islands form as a result of 3 general