How are coral reefs similar to tropical rain forests?
The basic physical structure of both communities is produced by organisms. Giant trees of rain forests and reef-building corals create a 3-dimensional framework that supports a vast assortment of organisms
Describe how coral reefs are built
Corals are built by polyps producing calcium carbonate skeletons.
What organisms are the primary builders?
The primary builders are the reef-building corals themselves.
hermatypic coral
Zooxanthellae, Reef builders, colonial, shallow, tropical seas
Ahermatypic coral
Non-reef building, Not limited to shallow or warm water, Some in polar seas
Describe the structure of a coral reef
Layers of cup-like skeleton of calcium carbonate as coral polyps lie in layers. This builds up the skeleton to grow upward and outward. It can take on many shapes as well
Describe how corals nourish themselves
By performing photosynthesis and passing the organic matter they make onto the coral. They also use their tentacles, mucus or mesentrial filaments
What role do zooxanthellae play
provide nutrients to their host
coralline algae
Algae that deposits good amounts of carbonate and binds/stabilizes the reef.
coralline algae their role in a coral reef
They are considered the 'glue' of the coral reefs
primary contributors to biogenous sediment in a coral reef
sea urchins, bryozoans, crustaceans, sponges and bacteria
conditions needed for coral reef growth
Coral reefs must be in shallow water, so there is light for the zooxanthellae to penetrate. The water must be clear and the average water temperature must be above 20 degrees Celsius (or 68 Fahrenheit)
coral bleaching
coral ends up expelling its zooxanthellae and most of its mucus
Why does coral bleaching occur
Rising water temperatures, Ocean acidification, Pollution/oil spills/shipping accidents, Overfishing, Natural disasters, Predation, Coral mining, Sunscreen/tourism
Describe the relationship between El Niño events and coral bleaching
When El Nino occurs, it warms the waters to a high temperature, thus resulting in coral bleaching. It results in a lot of reefs either quickly recovering, slowly recovering or dying.
eutrophication
is accelerated algal growth due to nutrient input. This causes algal to overgrow and smother corals
3 kinds of coral reefs
Fringing Reefs, Barrier Reefs, Atolls
Fringing Reefs
Most simple/common. Develop along the shore. Grows in a narrow band or fringe along the shore
Barrier Reefs
Lie along the coast, but further from the shore. In some cases, can be a complex system of smaller reefs
Atolls
A ring of reef/sand keys surrounding a central lagoon
reef flat
widest part of the reef
reef slope
steep, vertical part of the reef with the deepest cover
lagoon
water separated from the shore
sand keys
sand island
spur and grove formations
exposed fore-reef areas with a series series of finger-like projection alternating with sand channels
the theory of atoll formation developed by Charles Darwin
Atolls are formed by reef growth on a subsiding island, starting when a deep sea volcano erupts to form a island/seamount. Then, corals colonize the shores
trophic structure of a coral reef
There is a mutualistic relationship between the corals and zooxanthellae
defensive mechanisms of corals used to compete for space
can grow upward and branch out cutting off light from neighbors, some attack their neighbors, digest away tissue of another coral, can sting neighbor colonies with sweeper tentacles
epipelagic
Photic zone, 500 ft
Mesopelagic
the surface layer or sunlight layer, wide range of life
Deep Sea
a deep body of water with organisms adapted to cold, darkness, and very high water pressure
photic zone
Portion of the marine biome that is shallow enough for sunlight to penetrate
What do all of the habitats below the photic zone have in common?
life is much less abundant because of the lack of food that sinks below this zone
how oxygen is replenished in the deep sea
thermohaline circulation and the great ocean conveyor constantly replenish the supply of ocean to the deep sea
main thermocline
the zone where the temperature change marks the transition between the warm surface water and the cold deep water
Where is the main thermocline located?
mesopelagic layer
common adaptations do many animals in the mesopelagic zone possess
light organs that produce light
vertical migrators
swim bladder, well developed bones, well developed muscles
non migrators in mesopelagic
adapted to conserve energy, most have lost swim bladder, soft weak bones, lost spines and scales, neutrally buoyant
tubular eyes
Specialized eyes of many midwater animals that allow acute upward or downward vision
adaptations of mesopelagic species
countershading, black backs and silvery sides, laterally compressed bodies, uses bioluminescence to blend in with background light
counterillumination
The emission of light by midwater animals to match the background light
deep sea pelagic fish
drab gray or offwhite, fewer photophores, functionally eyes that are small or can be totally blind
adaptation for reproduction in deep sea pelagic fish
some become hermaphrodites, can use bioluminescence to attract same species, can release pheromones to attract mate, some bite their mates and attach to them for the rest of their lives
what organisms dominate on the deep sea floor
crustaceans
trophic structure around hydrothermal vents
seawater enters cracks and fissures in the earths crust and is heated to high temps, then causes black smokers and other mineral deposits, releases energy rich molecules