Flashcards in ocn15 Deck (23)
1. Explain why the distribution of benthic biomass mirrors the distribution of chlorophyll (i.e. primary production) in surface waters. (Also see fig. 15.1)
Life on the ocean's floor depends on the productivity of the primary producers; therefore shallow waters with photosynthesis, allow for more primary production for benthic life below them.
. Contrast the diversity of intertidal regions with other benthic environments
The greatest animal diversity is in the low tropical
diversity of algae is greater in the middle latitudes
rocky intertidal have moderate diversity
Describe the varying degrees of exposure to the atmosphere experienced by organisms in the intertidal zone, i.e., high, middle, and low tide zones.
high tide zone - relatively dry, covered with highest high tide
middle tide zone - covered with all high tides, exposed during all low tides
low tides - usually wet, but exposed during the lowest low tides
describe how shelled organisms like opihi prevent drying out during low tide.
ability to seek shelter within a shell
thick exterior or skeleton to prevent water loss
external surfaces covered by shell of rock to prevent water loss
adapted to a period of drying out without dying
List adaptations that enable organisms to live in the high tide zone
protective covering which prevents water loss
thick cell walls
able to attach themselves to rocks
Explain why more types of soft-bodied organisms live in the middle tide zone compared to the high tide zone.
seawater constantly bathes the middle tide zone
Give a commonly recognizable feature of the middle tide zone
List the common middle tide zone predators
carnivorous sea snail and sea star
Which common middle tide zone predator is related closely to marine jellies
Explain why marine algae and plants are common in the low tide zone
low tide zones are typically always submerged
Name a dominant second trophic level organism that feeds on marine algae.
Explain why marine organisms in sediment-covered coastal habitats require different adaptation than organisms in rocky shorelines
sediment covered shores are composed of unconsolidated material which is always changing shape and so require specific adaptations
Contrast biodiversity and species abundance on sediment-covered and rocky coastal habitats
there is less species diversity, but the organisms are found in greater numbers.
Explain the dominance of infauna in sediment-covered coastal habitats.
they can burrow into the sediment
List the different sediment-covered coastal habitats in the order of progressively lower energy and finer sediment size.
coarse boulder beaches, sand beaches, salt marshes, mud flats
Explain why decomposition is higher in sandy coastal habitats compared with salt marshes
water from breaking waves provide oxygen and nutrients which help breakdown dead material. the sediments are not rich in salt marshes as it is in sandy costal habitats
Describe the sediment-covered coastal habitat where intertidal zonation is best developed
supratidal, high tide, middle tide, low tide
Explain why most sandy beach organisms burrow into the sand
there is no stable fixed surface for the organism to attach to
an animal with two hinged shells
Explain why bivalves have a depth limit for burrowing into the sediment.
bivalves can only burrow deep enough where their siphon is able to reach the surface for water, food, and oxygen
long segmented body, with hard exoskeletons, and jointed limbs
List several crustaceans that inhabit coastal habitats
beach hoppers, sand crabs, barnacles, and shrimp