MAR 250 Final!

• Zones of the ocean (by descending depth):

  • Intertidal zone (between high and low tide)
  • Continental shelf = neritic zone
  • Oceanic = pelagic
  • Epipelagic = 0-200m
  • Mesopelagic = 200-1000m
  • Bathyal = 1000-4000m
  • Abyssal = 4000-6000m
  • Hadal = trenches = >6000m
• What is shifting baseline syndrome?

  Concept that the baseline for a natural community has shifted over generations because we have forgotten the original natural state
• What does fishing down the marine food web mean?

  Overfishing of top predators leads to a decrease in their abundance and a shift towards lower trophic levels
• What is a marine protected area?Why is it important?

  • Fraction of ecosystem area/volume set aside to allow populations to thrive
  • Important because success can spill over into remaining unprotected sites
• Distinguish between conservation, preservation, and restoration?

  • Conservation = preventing ongoing degradation; minimizing unsustainable use of resources
  • Preservation = area set aside and protected in its natural state
  • Restoration = actively trying to return degraded resource to its original state
• What are photoautotrophs? How do they capture energy?

  • Use pigments (chlorophyll) to capture energy from sunlight
• Difference between photosynthesis and respiration?

  • Photosynthesis = process by which autotrophs convert sunlight to carbohydrates
  • Respiration = process by which organisms break down carbohydrates to be used for energy
• What are the limiting factors of primary production, and why are they limiting?

  Light:

  • Primary production depends on light intensity and depth of light penetration
  • Highest intensity light in epipelagic zone, total light decreases exponentially with depth

  Nutrients:

  • Nitrogen, phosphate, and silica are most limiting
  • Nutrients are mostly consumed in photic zone and remineralization occurs below photic zone via decomposition
• Inner shelf vs coastal vs open ocean primary productivity?

  Inner shelf: Inputs from freshwater, greater PP than open ocean but less than coastal zones

  Coastal: inputs from freshwater as well as seawater mixing, more productive than both others

  Open ocean: least productive, usually limited by nutrients because of limited inputs
• What is eutrophication?

  High nutrients in water leads to algal bloom, which then consumes oxygen and can cause hypoxia
• How does the light/dark bottle experiment work?

  The light bottle measures both photosynthesis and respiration, and the dark bottle measures respiration only.

  • Can be used to calculate gross primary productivity
• Differences between prokaryotes and eukaryotes?

  Prokaryotes (ex. bacteria):

  • Usually single cell
  • Lack distinct nucleus, nuclear membrane, organelles

  Eukaryotes (ex. plants, animals, protozoa)

  • Have cellular nucleus, nuclear membrane, organelles, chromosomes
• Macroalgae taxa and colors

  • Red = Rhodophyta
  • Green = Chlorophyta
  • Brown = Phaeophyta
• Seaweed anatomy

  • Blade = leaf-like structures
  • Stipe = stem-like structures
  • Holdfast = root-shaped base
  • Gas bladder = help algae face surface for ample light for photosynthesis
  • Thallus/frond = body
• How are marine angiosperms different from terrestrial angiosperms?

  Marine angiosperms often use a rhizome system to spread - interconnected

  Different tolerances to saltwater

  Examples: mangrove trees, cord grass, dune grass, sea grass
• What are stromatolites? Why are they important?

  Stromatolites = unicellular prokaryotes with bacterial cell walls - formed by layers of cyanobacteria

  • Some of the oldest fossils ever, oldest fossils visible to naked eye
• What are the two common pelagic cyanobacteria? Why are they important?

  • Prochlorococcus = responsible for 10-50% of all open ocean primary productivity
  • Trichodesmium = diazotroph (nitrogen-fixing), found in nutrient-poor tropical and subtropical waters
• Plankton size classification from largest to smallest:

  • Megaplankton = >20cm (jellyfish)
  • Macroplankton = 2-20cm (pteropods, krill)
  • Mesoplankton = 0.2mm-2cm (copepods, Foraminifera)
  • Microplankton = 20-200um (ciliates, coccolithophores)
  • Nanoplankton = 2-20um (diatoms, dinoflagellates)
  • Picoplankton = 0.2-2um (Small eukaryotic protists, bacteria)
  • Femtoplankton = <0.2um (viruses)
• Diatom characteristics?

  • Most productive phytoplankton
  • Occur singly or form chains
  • Denser than seawater, do not swim
  • Size range from nano to microplankton
  • Encased in silica shell with two valves
  • Can reproduce asexually (binary fission) or sexually
• Why is shape important for plankton?

  • Spines help prevent predation
  • Large surface area to volume ratio prevents sinking out of photic zone
• Dinoflagellate characteristics?

  • Organic test
  • 2 flagella, one for rotation and one for moving forward
  • Size range nano to micro
  • Asexual and sexual reproduction
  • Many species are heterotrophic
  • Like warm water
• Coccolithophore characteristics?

  • Unicellular
  • Reproduce through cell division
  • Spherical
  • covered in calcium carbonate plates = coccoliths
  • Vital contributor to calcareous ooze
• Silicoflagellate characteristics?

  • Star shaped silica skeleton
  • Two flagella of varying lengths
• Which phytoplankton contribute to siliceous ooze?

  Diatoms and silicoflagellates
• Copepods key features?

  • Long pair of antennae
  • Feed on phytoplankton or smaller zooplankton
  • Crustaceans
• Krill key features?

  • Shrimplike crustaceans
  • Feed using setae to form a basket
  • Feed on phytoplankton and smaller zooplankton
• Salps key features?

  • Subphylum Urochordata
  • Incurrent and exit siphons on opposite ends of body
  • Can be solitary or colonial
• Larvacea key features?

  • Subphylum Urochordata
  • Have tail, resemble tunicate swimming larvae
  • Tail generates current through mucus house
• Chaetognatha characteristics?

  • Phylum Chaetognatha
  • Arrow worms
  • Torpedo shaped
  • Carnivorous
  • Holoplankton
• Pteropod characteristics?

  • Holoplanktonic mollusc
  • Foot is modified to wings
  • Reduced aragonite shell
  • Suspension feeders or carnivorous
• What are the three types of protistan zooplankton?

  Foraminifera, radiolaria, ciliates
• Foraminifera characteristics?

  Phylum Foraminifera

  • Calcium carbonate skeletons
  • Contractile pseudopodia trap food particles
  • Foram ooze = calcareous
• Radiolaria characteristics?

  Silica skeletons

  Radiolarian ooze goes deeper than foram ooze
• Ciliates characteristics?

  Common in plankton, some are mixotrophic but also eat phytoplankton and bacteria

  Elongate, covered with rows of cilia
• What are swim bladders, and how do they function?

  Gas-filled organs that help maintain buoyancy

  • Fish can regulate amount of gas in swim bladder
• What are the two types of swim bladder regulation?

  Physostomous = direct connection to gut allows fish to gulp air to regulate gas volume

  Physoclistous = regulate gas physiologically in circulatory system
• How do swim bladders differ in bony and cartilaginous fish?

  Cartilaginous fish do not have swim bladders. They instead have large, oil-filled livers, lightweight skeletons, and specialized fins to stay buoyant
• Key features of Osteichthyes and examples?

  Bony skeleton, gill covers, swim bladder

  Examples: tuna, clownfish, flounder, etc.
• Key features of Chondrichthyes and examples?

  Cartilaginous skeleton, replaceable teeth, external gill openings, and placoid scales (help with buoyancy)

  Examples: sharks, skates, rays
• What is the most diverse order of sharks?

  Charcarhiniformes - requiem sharks