unit 9: intertidal zone

intertidal zone

• area between the highest high tide and the lowest low tide

• also known as: coasts

• “where the land meets the sea”

soft bottom community

• soft sandy bottom (gravel, sand, silt, clay)

• consists mostly of infaunal organisms (sand crabs, bivalves)

• consists of meiofaunal organisms (worms, copepods)

• more common along the East Coast of US

• commonly known as beaches

• less geologically active

rocky shore community

• regularly exposed to air (due to tidal flow)

• known as the "littoral zone" (due to Littorina planaxis -periwinkle snail )

• more common on the West Coast of US

• hard "rocky" bottom

• occur on recently uplifted or geologically young coasts or where erosion occurs (edge of tectonic plate)

• temperature and salinity fluctuate greatly (due to tidal flow)

• consists mostly of epifaunal organisms ↳some motile (move), some sessile (attached) - snails, anemones, mussels, crabs, seastars

periwinkle snail

• commonly found along rocky shorelines in the intertidal zone

• small, marine snails

• spread rapidly along the eastern coast of North America, especially in the intertidal zones.

• graze on algae

• it can create a ripple effect throughout the food web, impacting species that rely on algae as their primary food source.

epifaunal

• organisms that live ON top of substrate

motile

• mobile

• can move

sessile

• attached

lichens

• looks like tar

• fungus and plant symbiosis

• provide structure, protection, and moisture retention.

• perform photosynthesis, producing food for both the fungal partner and themselves.

  ↳allows lichens to survive in harsh conditions, where individual organisms might struggle.

ecological succession

• replacement of organisms

• the natural process of change in the species composition of an ecosystem over time, influenced by a variety of factors

  ↳plays a critical role in shaping biodiversity and ecosystem structure.

competitive exclusion principle

• when dominant species takes over

• when two species that are too similar in their use of resources cannot live in the same place indefinitely, and one will eventually prevail (take over)

wave shock

• force of striking waves

• effect of high tide

• affects intertidal organisms bc they cant withstand the force of wave shock

hydraulic pressure

• to the pressure exerted by water within organisms or environments.

• plays a role in supporting the structure and movement of marine animals, circulating fluids in their bodies, and influencing the functioning of marine ecosystems.

• the weight of the water above creates immense pressure on organisms that live there

byssal threads

• strong fibers made of protein that mussels use to attach to substrates to prevent being washed away by strong tides

• adaption for high tides

swim bladder

• adaptation for high tides

• A gas-filled sac that provides many bony fishes with buoyancy.

• intertidal fishes lack this to be able to sink down to the bottom to prevent being washed away by tides

abrasion

• effect of high tides

• injuries or tiny cuts on skin/surfacec

closing down

• adaptation for high tides

• when organisms use their covering or shell that closes and is able to hold water

• helps contain water and prevent drying out

desiccation

• substrate remains wet after the tide goes out,

• not a huge problem

• drying out?

suspension feeding

• used by sessile organisms like sea anemones

• the capture and ingestion of food particles that are suspended in water

deposit feeding

• used by sessile organisms

• Animals that eat organic matter that settles to the bottom.

grazing

• feeding used by mobile organisms like snails

• when a herbivore feeds on low-growing plants such as grasses or other multicellular organisms, such as algae

filter feeding

• Animals that actively filter food particles from the water.

• They are a common type of suspension feeder

infaunal

• organisms that live IN the substrate

meiofaunal

• organisms that live IN BETWEEN the sediments

coarse sediment

• (gravel, sand)

• large, gritty (sandy bottom)

• water drains quickly due to interstitial space

• desiccation increases

• no organic matter

• no cellular respiration, more oxygen

  ↳food poor; oxygen rich

fine sediment

• (silt, clay, both comprise mud)

• small, smooth (muddy bottom)

• water drains slowly due to little space

• desiccation decreases

• organic matter trapped

• cellular respiration (anaerobic), no oxygen (anoxic)

• smelly (hydrogen sulfide)

  ↳food rich; oxygen poor

drainage

• large/coarse - water drains quickly

• small/fine - water drains slowly

• poorly sorted/mixed - water movement is inefficient (water is blocked)

interstitial space

• the small spaces or voids between particles in sediment or rock

anoxic

• an environment or condition where there is a complete lack of oxygen.

detritus

• the organic material that is dead or decaying, typically derived from plant and animal matter