Stay in the Zone
Sara Painter and Vanessa Thulsiraj
Ocean Zones
Categorized by light, depth and distance
Photic versus Aphotic zone
Sunlight Availability
Photic zone:
• Euphotic zoneportion of photic
zone where
photosynthesis occurs
• 0-200 meters
• The sunlit zone
Aphotic zone:
• 200 meters to ocean
floor
• Little to no sunlit zone
• Critters:
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
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
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
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
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
The Sinking Problem
• All plankton must stay in • Phytoplankton are the basis
the photic zone
of the marine food chain
• Either they need
sunlight for
photosynthesis
• Or they are part of a
food chain who’s
foundation is
phytoplankton
Phytoplankton produce half of the worlds oxygen!
Form and Function
Plankton avoid
sinking by:
• increasing their
surface area
• or decreasing
their density
• Spines and
flattened bodies