1. Sara Painter and Vanessa Thulsiraj
Stay in the Zone
Sara Painter and Vanessa Thulsiraj

2. Ocean Zones Categorized by light, depth and distance

3. Photic versus Aphotic zone Sunlight Availability
Euphotic zone- portion of photic zone where photosynthesis occurs
0-200 meters
The sunlit zone
Critters:
Aphotic zone:
200 meters to ocean floor
Little to no sunlit zone

4. Intertidal, Neritic and Oceanic Zones Distance from coastal shoreline
Intertidal zone = area between high and low tide
Neritic zone = area between the low tide and continental shelf
Oceanic zone = area beyond the continental shelf (open ocean)
Critters
Intertidal zone= harsh area to live because of constantly changing environment due to crashing waves, periodic dry periods, and rapidly changing temperatures, salinity and oxygen levels. The tidepools reside in the intertidal zone showing that some species are well adapted to this constantly changing environment.
Critters: Sea anemome, mussels, barnacles, crabs,
Neritic zone= rich in biomass and species, only 5% of ocean but supports 90% of commercial fisheries. Ideal habitat due to light, photosynethesis can occur, nutrients are available from land masses, shallow bottom provides shelter and habitats. The neritic zone lies entirely within the photic zone. Bacteria, bluefin tuna, mackarel, algae, sea turtles, dophins, plankton, eels
Oceanic zone= known as open ocean, it lacks nutrients, resulting in smaller populations as compared to the neritic zone.

5. Pelagic, Benthic and Abyssal Zones Water Depth
Pelagic zone = all depths of the open ocean.
Benthic zone = all sea bottom surfaces
Abyssal zone = part of benthic zone in deep ocean floor (abyssal plains)
Critters

6. Benthos Benthos means “bottom”
Any organisms living on or in the ocean bottom
Most found in shallow costal ocean floor
Examples include sea stars, corals, crabs, seaweeds, snails, sea cucumbers, and sea squirts

7. Nekton Nekton means “swimming”
Any organisms that is strong enough to move against the ocean currents, by swimming or propulsion
Can determine their position in environment and some are capable of migrating long distances
Include many adult fish, adult squid, marine mammals and marine reptiles

8. Plankton Plankton means “drifter” or “wanderer”
Any organisms that is not strong enough to swim against the currents
Phytoplankton = plants which need light for photosynthesis
Zooplankton = small animals that feed on other plankton

9. The Sinking Problem All plankton must stay in the photic zone
Either they need sunlight for photosynthesis
Or they are part of a food chain who’s foundation is phytoplankton
Phytoplankton are the basis of the marine food chain

10. Phytoplankton produce half of the worlds oxygen!
Kinda a “why should you care” slide

11. Form and Function Plankton avoid sinking by:
increasing their surface area
or decreasing their density
Spines and flattened bodies
This could be used to review after the activity:
You can make a worksheet to go with this lesson, if desired. Students could also do a lab write up or some follow up questions. An example follow up question would be:
1. estimate the time it would take the slowest and fastest plankton you observed to sink below the photic zone given their sinking rate. This requires that students actually time the sinking rate of their plankton using a stopwatch.