FINAL Flashcards
What is the average salinity of the ocean?
Average salinity is usually considered to be 35 ‰.
What is a thermocline?
where wave and current action no longer mix the waters.
What are surface currents run by?
Wind
What causes spring tides?
When the Sun and Moon are aligned with respect to the Earth, their bulges will overlap and be additive (new/full)
What causes neap tides?
When the Sun and Moon are at right angles with respect to each other, their bulges will be offset and will be subtractive (wax/wane)
What are semidiurnal tides?
two high tides and two low tides of relatively equal height each day
What are diurnal tides?
only one high and one low tide each day
How do you find the wave base?
depth equal to half the wavelength (determines surface mixing)
What energy sources cause waves?
Wind, storm surges, tsunamis, Seiches
What is fetch?
the distance that wind blows over open water, and thus the distance over which wind “forces” the formation of larger waves
What is shoaling?
If the bottom becomes shallow enough that the wave base is below the bottom, the wave is said to be…
What is the intertidal zone?
That area of the shore that is exposed to air during low tide, and is submerged at high tide.
Why is the intertidal zone stressful?
they must survive, sometimes for many hours, exposure first to air and then to water.
What is zonation?
discrete areas inhabited by different groups of organisms. In the intertidal zone these areas appear as relatively horizontal bands parallel to the shore
What are abiotic factors? List some.
Not caused biologically (temperature, desiccation, anoxia, etc.)
What are biotic factors? List some.
Caused biologically (competition, predation)
What is the rocky intertidal?
Rocky slopes, faces, and bouldersGenerally stable in the face of wave action Usually has a complex 3-D structure, allowing patchy distribution of organisms
(i.e., sun-exposed and shaded areas, wave-exposed and protected areas;
more or less water flow, etc.)
c. Since organisms can’t burrow into rock (generally), they must cling to the
surface, or to other organisms, or find protected spots
What is hypoxia?
Causes metabolic depression and death due to lack of oxygen
What is UV exposure?
UV radiation, DNA damage
What is dessication?
loss of water due to exposure to air during low tide
What is wave action?
Waves
What is predation?
Getting predated (usually eaten)
What does it mean to be sessile?
Being unable to move by themself
What is competition?
Competing for space
What are the zones of the intertidal?
Supralittoral, midlittoral, infra littoral, subtidal
What is the supralittoral fringe?
Area affected by wave spray, but rarely by high tides; borders the “supralittoral” (i.e., terrestrial) zone
What is the midlittoral zone?
Broadest area of the intertidal, and is often subdivided into upper midlittoral, lower, etc.
What is the infralittoral zone?
Usually covered by sea water, except during spring tides
What is the subtidal zone?
the rest of the ocean (never exposed to air)
What is broadcast spawning?
external fertilization
What is synchronous spawning?
coordinate release of gametes in time
What are Lecithotrophic larvae?
depend on a large yolk sac provided by the mother. They don’t need to rely on the external environment for food, but when the yolk is consumed, the larva must metamorphose and settle, whether it is in a good
location or not
What are planktotrophic larvae?
have very little yolk, and must feed
themselves, consuming other plankton in open water. They are reliant on good environmental conditions (i.e., abundant prey), but can delay metamorphosis when necessary
What is the intertidal zone on a sandy beach called?
Foreshore
What is the Upper portion beyond the reach of the waves on a sandy beach called?
Backshore
What are infauna?
Burrowing organisms (crabs, clams, worms)
What are meiofauna?
extremely small animals that live within the
interstitial water of sandy sediment (live in between sand grains) like flatworms, annelids, etc
What is an estuary?
the area where a freshwater system (stream or river) meets the ocean, and the flow is slow enough that organic material settles to the bottom to form sediment.
What are salinity gradients?
Estuary waters can vary from
the salinity of sea water (35‰, or even higher depending on evaporation) to fresh water
What does brackish mean?
Water that is intermediate in salinity between seawater and freshwater
What is a salt wedge?
Salinity gradients with depth can develop when in-flowing freshwater (less dense) over-tops a lower layer of salt water
What is euryhaline?
organisms that can survive large variations in salinity