Ecology test 3

intertidal zone; where is it

narrow fringe area between high and low water

whats the most important environmental factor in the intertidal zone

tides

diurnal tides

location has a single high and single low tide

semidiurnal tides

two highs and two lows per day

mixed tides

mixture between diurnal and semidiurnal

_____ of the tide varies from day to day

height

why are the tides in intertidal zones important

duration of exposure and time of exposure

tidal rhythms examples

running of the grunion and spawning of the horseshoe crab

environmental conditions of intertidal zones (3)

temperature, wave action, and salinity

temperature in intertidal zones

the organisms are more subjected to more dramatic variations in temp

wave action in intertidal zones

exerts more influence on organisms and communities; mechanical effect (smashes and tears away); extends scope

salinity in intertidal zones

excessive rain/flooding during low tides; tide pool

adaptations of intertidal organisms

avoiding or minimizing the stresses of daily exposure to air

adaptations to withstand water loss in intertidal zones (3)

mobility, dense aggregations, and close up shop

adaptation of mobility in intertidal zones

mobile animals move into moist cracks, crevices, or burrows

adaptation of dense aggregation in intertidal zones

dense groups of organisms; reduce SA; create cracks and crevicesada

adaptation of closing up shop in intertidal zones

close their shells at low tide

rocky intertidal shores

most densely inhabited; greatest diversity of animals and seaweeds

zonation

horizontal banding of organisms

variations of zonation in intertidal zones

slope, tidal range, and exposure to wave action

broad zones of intertidal zones

gradual slope, greater tidal range, and exposed areas

zone classification (3 zones)

supralittoral fringe, midlittoral zone, and infralittoral fringe

supralittoral fringe

uppermost zone; lower limit is the upper limit of barnacles and extends to the upper limit of snails

midlittoral zone

broadest in scope; upper limit is the upper limit of barnacles and its lower limit is the upper limit of kelps

infralittoral fringe

lowest zone; extends from the lowest low tide to the upper limit of large kelps

2 physical factors for causes of zonation

desiccation and temperature

5 biological factors for causes of zonation

competition, predation, grazing, positive interactions, larval settlement

biological factors of zonation in intertidal zones are ____ complex, ____ subtle, and ____ linked to other factors compared to physical factors

more, more, closely

competition in zonation in intertidal zones

doesn’t occur if there are plenty of resources

what one resource is almost always limited in the intertidal zone

space

Whats the name of the dominant space competitor on open-coast shores

Mytilus californianus

Grazers

Herbivores regulate the upper and lower species in the intertidal; they determine which species

species diversity is much ____ in the atlantic than in the pacific

less

algal grazing has led to the evolution of algal defenses (3)

calcification of tissues, chemical defenses, multiple life stages

positive interactions in intertidal zones (2 examples)

mussel beds provide refuge from physical stresses for many organisms; intertidal seaweeds provide shelter and shade for organisms and extend their range in the upper intertidal

most intertidal organisms have a ______ larval stage

planktonic

large variation in recruitment is drive by what facots and conditions (2)

oceanographic conditions and biological factors

oceanographic conditions (2)

strong wilds that lead to upwelling and surface currents moving offshore, strong spring rains can mean decrease in ‘flushing time’ of the bay (washing larvae out of the area)

biological factors of recruitment in intertidal zones (1)

juvenile rockfish in kelp forests are significant predators of barnacle larvae

tropical rocky intertidal characteristics (6)

high temps (basically constant), high predation, mobile inverts abundant, less competition for space, larger # and diversity of consumers, lots of periwinkles

temperate intertidal characteristics (3)

lots of mussels and barnacles, large body size/residence in high intertidal are important refuges from predators, macroalgae have large impact on community structure

coral reef facts (5)

inshore waters dominated by coral reefs, greatest diversity, ½ calcium in oceans taken up by reefs as CaCo3 (so they remove hella carbon per year from atmosphere), primarily tiny colonial corals

biological factors in intertidal zone

settlement preference, competition for space and food, predation

settlement preferences (2)

soft versus hard, zonation

two types of corals

hermatypic and aheramtypic (build reefs vs dont)

reef building corals in phylum cnidaria (one class, one order)

class anthozoa, order scleractinia (stony corals)

example of zonation settlement preference

barnacle settles middle-upper OR throughout intertidal (cant survive exposure any higher)

nutrition for coral

colonial (polyp), carnivorous animals (use nematocysts), colonies of thousands of individuals (total area for feeding is large), feed only during the night time

competition for space and food in intertidal zone

can exclude organisms in intertidal zone

example of competition for space and food in intertidal zone

barnacles grow larger and faster than others and physically excludes it for space

why are the pacific coasts not entirely M. californianus

predation, habitat, human activity, climate, etc.

meroplankton explains only a tiny amount of corals total food requirements. where does the remainder of their food come from?

symbiotic relationship with zooxanthellae (dinoflagellate)

predation in intertidal zone (what animal)

predatory sea stars

how does a zooxanthellae get food from dinoflagellate

photosynthesis (which is then transferred to the corals)

what do dinoflagellates get in their symbiotic relationship with zooxanthellae

protection (coral with energy) and nutrients

common characteristics of rocky shores (5)

no strong detrital component, lots of suspension feeders, lots of macroorganisms, complex predator-prey and competitor interactions, temperate (similar tidal zonation)

how are zooxanthellae acquired

directly (asexual budding) or indirectly from the environment

tide pools characteristics (3)

salinity changes, temperature changes, and oxygen depletion

how do corals get color

zooxanthellae (they feed by photosynthesis and have color)

how does coral get bleached

zooxanthellae get stressed and dip

growth and calcification of a coral colony (requirements)

light, growth rate varies by species, growth rate varies by location

intertidal fishes (4)

clingfish, gobies, blennies, sculpins (and other visitors)

how does light help with growth and calcification of coral reefs

zooxanthellae increase the calcification of corals and growth rate of colonies

how does growth rate vary by SPECIES in coral reefs

branched corals grow more rapidly than massive or mound shaped corals

how does growth rate vary by LOCATION in coral reefs

corals at a greater depth are more thin and fragile

why are corals at a greater depth more thin and fragile

greater depth = cold and dark (not ideal)

reproduction in coral reefs

asexually and sexually

sexual reproduction in coral reefs

results in free swimming PLANULA larvae

asexual reproduction in coral reefs

new individuals bud off the parent

characteristics of planula larvae (3)

sexually mature at 7-10 years, hermaphroditic, seasonal broadcast spawners

recruitment in coral reefs

planulae disperse in open water few days/weeks until settle to start new colony, and the rate of recruitment is variable in time and space

why is the rate of recruitment in coral reefs variable in time and space

mortality of new colonies is thought to be high

SIX major physical factors limit coral reef development

temperature, sunlight, depth, salinity, sedimentation, exposure to air

reef distribution (temperature)

no reefs below 18 C, optimal at 23-25 C (upwelling makes areas cold)

reef distribution (depth)

do not develop it waters deeper than 50-70m, optimal at 25m

reef distribution (light)

sufficient light for photosynthesis by symbiotic zooxanthellae

reef distribution (salinity)

corals are marine organisms and intolerant of salinity change

reef distribution (sedimentation)

can clog feeding structures and smother the corals, turbidity reduces light

3 types of reefs

Fringing, barrier, and atolls

Barrier reef

Distance between land and reef

Atoll reef

Circular/horseshoe shaped reef far from land usually deep

Subsidence theory

Fringing reef → barrier → atoll (island sinking)

Why does an island sink (subsidence theory)

It used to be a volcano, cooled down, and got denser

how can an island sinking affect the coral around it

If the island sinks faster than the reef builds on top of itself, it will de

Enewetok

In the Marshall Islands, an atoll reef

Marshall Islands

100 B.C. And important in ww1 and ww2; ships were refueled there

Donation on coral reefs

Great diversity of life

Fringing reef

Reef surrounds land

zonation on coral reefs (diagram)

1. Outer seaward slope 2 windward reef margin 3. Algal ridge 4.reef flat

5. Seaward beach of island 6. Lagoon beach of island 7. Lagoon floor

8. Lagoon reefs 9. Leeward reef flat 10. Leeward reef margin 11. leeward reef slope

Depth zonation in coral

Reefs on surface, branching on top of slope, massive corals at bottom of slope

Competition in coral reefs

Competition for light and space (lack of space in reefs) to grow higher and wider by growing faster

Exploitative competition n coral reefs

Up right, rapid growing corals grow over encrusting massive corals; slow growing corals have adapted to tolerate shade

Interference competition

Slow growing corals extend digestive filaments and kill adjacent competing species