Card Set Information
marine intertidal zone
marine biology intertidal zone
What is the tidal range of Gulf of Mexico and why?
low tidal range: 2ft due to Wind effect
Between highest tide level and lowest
Distance between highest and lowest tide levels
What have the most extreme tidal range; give example
long, narrow bays have most extreme tidal range ex East Canada- Bay of Fundy-25ft tidal range
list high and low tides etc
what tide is desired for field trips? launching boat/scuba?
Field trip-low tide
Tides are measured from the ?
What is the zero mark?
Its set by observation-they keep record of highest and lowest tide for year; avg measurement=> ?
What is the intertidal zone?
Area with tidal effects
What is the subtidal area?
Area below intertidal to deepest wave effects
Why do we have tides?
earth rotates around sun, moon rotates around earth; Moon pulls at water on earth on same side of it=>high tide
Opposite side of earth has low tide
What is spring tide? What causes it?
When tide seems to "spring" up
: Higher highs and lower lows
Occurs was EATH->moon-> sun in that order=>higher tidal range
What is neap tide? Cause?
Lesser tidal range
Occurs when sun and mood are perpendicular
Why may tides table be off by couple hours?
Gradually move as earth rotates
Diurnal tides; where do they occur?
1 high and 1 low tide per day
2 highs and 2 lows per day at 6 hour interval
Pacific coast of USA
Higher High(HHT) 6ft
Lower low (LLT) -2ft
Lower high(LHT) 4ft
Higher low(HLT) 2ft
Waves of tidal flow tends to raise water level on 1 side of basin
Occurs in semi enclosed areas
Ex Gulf of Mexico
Physiological challenge on marine life at low tide
Respiration-low water levels or water retreats
: drying out
Exposure to wind and rain
Exposure to land-based predators
: birds are major danger, mammals(coyotes/racoons)
Trampling &crushing and sand compaction
When little rain=> higher salt=> when dry out -salt formation= BAD
Especially at extreme high tide
Challenges at high tide: COMPETITION
Surf-wave banging on tiny organisms can crush or rip away from perch
Cope by hide, rubbery body, flexible; hang on tight
Sand abrasion-act like sand paper
Exposure to Sea water predators-fishes, morays, crabs, octuopus, starfishes
Ex baracuda into shallow water in search of food
How to cope w/ low life
Leave-fish will swim offshore or go into deeper pools
Dig in-burrow into sediment
Cause problems b/c less oxygen
Stay in a shady place
: light ,pale or camouflaged
Helps against predators and heat
Some species are strictly intertidal
: ocypode-only live in intertidal b/c they can't compete
Can be refuges
Rock jetties with overhang
May form microhabitats
At low tide may go under and will see things only seen when diving normally
Can also have BAD microhabitats-hypersaline, or dead, rotted seaweed or human caused
Effects of Sea Spray at very highest levels
Moisture and salt-causes problems with rooted plant
Salt gets on leaves=>desiccation of leaves
Some things can handle that