MAR105 Review sheet – Benthos
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Understand that benthos refers to organisms (plants, animals or protists) that live on or near the
ocean bottom.
Understand that benthic habitats may be shallow or deep.
Know that most benthic animals are sessile (immobile).
Know that >98% of all marine organisms are benthic.
Understand that the majority of those organisms are found on the continental shelf.
Understand that intertidal zones are among the most densely-populated areas on Earth.
Know that challenges to benthic organisms in intertidal zones include desiccation, strong wave
activity, changes in temperature, salinity, pH and/or oxygen content, and predation.
Know that the spray zone exists above the spring high tide line.
Understand that the intertidal zone is the region between the highest high tide and the lowest
low tide.
Understand that the high tide zone is relatively dry; the middle tide zone is alternatively wet and
dry; and the low tide zone is usually wet.
Know that most organisms in the high tide zone are sessile.
Understand that the middle tide zone has the greatest biomass (relative to the high and low tide
zones).
Know that seaweeds are multi-cellular protists.
Know that seaweeds do not have roots, but rather have a holdfast to anchor themselves to
substrate.
Understand that salt marshes are highly productive habitats, characterized by special plants
capable of surviving in and out of salt water.
Know that salt marshes form protective barriers against erosion, promote new land formation,
filter out excessive nutrients and pollutants, and provide protective habitat for larval fish and
shellfish species.
Understand that sand and cobble beaches are extremely harsh environments and characterized
by little biomass.
Know that mole crabs and coquina shells are common along Long Island sandy beaches.
Know that reef-building corals secrete calcium carbonate.
Know that an individual coral is called a polyp and reproduces sexually and asexually.
Know that coral are Cnidarians and are related to jellyfish and sea anemones.
Know that zooxanthellae are symbiotic dinoflagellates that provide coral with their color and
organic compounds.
Understand that coral bleaching is the process by which the coral expels the zooxanthellae or
the zooxanthellae expels itself from the coral.
Understand that coral bleaching frequently occurs during El Nino events and may be reversible.
Know that coral bleaching can occur when the temperature rises to 1°C higher than the normal
summer high temperature.