Corals Flashcards
What phylum are corals in and why?
Cnidaria , presence of stinging cells on tentacles used to capture prey and as defense
What is the soft body of the coral called and what is it enclosed by?
Polyp
Hard shell of calcium carbonate
What is the advantage of having a cup shape
The tentacles can retract into it for safety
Hermatypic corals are what type of corals? What do they normally contain, how are they distributed
Reef builders
Zooxanthellae symbiotic photosynthetic dinoflagellates
Temperature and water quality
Ahermatypic corals , what are they the opposite of
Do not build reefs
No zooxanthellae
Not restricted
Corals live in what kind of water ? And what does this word mean
Oligatrophic, low nutrient
What is the definition of coral reefs ? What do they share and why?
Groups of coral polyps interconnected by thin layers of tissue
Nervous system and digestive connection
Entire colony came from on polyp that reproduced asexually to form
What does each polyp lay down so that the rest builds ? How wide is each polyp , however …..
CaCO3
1-3 mm
Large sizes and weigh several tons
If zooxanthellae are supplied with enough ? They can feed the whole coral
Light
How much percent of energy is from zooxanthellae
98%
Difference between feeding at night and during the day
Day autotrophic (zooxanthellae) Night heterotrophic (tentacles)
What are the stinging cells called , what do they allow them to feed on? What do corals produce to capture these small organisms
Nematocysts , small organisms in the water like zooplankton , mucous
How else can corals feed (think extensions) ?, what do these filaments secrete?, how do they extend these ?
Extensions of gut wall called mesenterial filaments
Digestive enzymes
With enzymes lowing coral to feed and digest food outside of the body
Conditions required for reef growth(7)
Hard substrate Light optimal Narrow temperatures Narrow salinity ranges Low sediment load in water Low pollution Narrow range of pH
Corals produce which two ways? Asexual reproduction allows for? Sexual reproduction results in the creation of ?
Sexually and asexually
Growth of buds from single polyp
Planula larvae that is able to ride on water currents to new environment (settle out to begin growth on existing reefs or other substrate )
Light must be able to penetrate in order for what to take place? Corals are normally found in what waters due to this? However some may be found as far down as ? Where are corals mostly found (land forms)
Symbiotic relationship between zooxanthellae and corals
Shallow
150 feet if penetration of light permits
Continental shelves near islands or seamounts due to light/depth dependency
What does antecedent topography mean ?
Dead corals
Reef building corals tolerate a low what as compared to other organisms ? Corals can only reproduce and grow at what temperature ? Water over what temperature can cause corals stress?
Temperature range
68 degrees Fahrenheit
86 otherwise bleaching occurs
What other events besides high temperatures can cause coral bleaching , widespread bleaching occurs because of events like
Poor water quality, increased sediment, wave stress or disease
El Niño (increased water temps) and hurricanes
Corals maintain good health in what salinity , where do they normally not exist ? Low salinity can result in what
35 ppt
Near mouths of rivers
Coral bleaching
What happens when suspended sediments land on corals ? What happens when there is reduced water clarity?
Cause damage
Zooxanthellae photosynthesis is reduced or stopped
Low levels of p…….. Can kill ? High nutrient levels allow what to rise ? Increased algal growth can shade ?
Pollution
Algae levels
Light sensitive corals and zooxanthellae
Which corals seem to be dominant in shallower waters and why? Which corals seem to be dominant in deeper areas and why?
Taller more branching , intense competition for space and light
Flatter forms, assist in catching all light possible
Seven types of corals
Plate like, foliaceous (leaf like), columnar, massive, branching, free living, encrusting
The rest of the examples without importance
Cnidarians (hydrozoans or anemones )
Sponges cement rubble into substrate
Bryozoans
What is cementation and what does it contribute to?
What is this process balanced by (2 things)
Secondary secretion
Build up of reef structure
Erosion and consumption
Fringing reefs are the … And most… Form or reef ? Where do these reefs develop near ? The develop as what ?
Simplest and most common
The shore in tropical areas
Narrow strips along the shore
Some can encircle
What do fringing reefs consist of ? The reef is …, …. And ….. And may be exposed at what tide ? The reef slope is much more ? And is not exposed to what? What is the reef crest ? Growth is normally high in what area
Inner reef flat and outer reef slope Flat, wide, gently sloping Low tide Steep, air Shallow upper edge of the reef coast Reef crest
What does the reef slope contain on fringing reefs ? The number of species is higher in which two places on fringing reefs ? Why is growth slower on reef flat ?
Living and dead corals : sea grasses, soft corals, algae a and invertebrates
Slope and crest
Runoff from land like sediment freshwater pollution and wave action
Where do barrier reefs grow ? How are they different from fringing reefs ?, which is the second largest barrier reef in the world and where is it?
Along shore or farther from shore
Deep lagoon between shore and reef
Belize Central America
What is the typical construction of a barrier reef ? The slope of the fore reef is much more… Than the back reef slope , what happens to the depth in this area ?
A back reef slope , a reef flat, a crest me a fore reef slope
Pronounced
Depth drops quickly
What happens on the back reef slope or reef flat , enough sediments may accrue to form what? These islands are called what in Florida and what every where else
Waves wash up sediment on to these parts and causes reduced coral growth
Islands
Keys/ cases
Where is coral growth normally the highest on barrier reefs ? As the same with fringing reef where is species diversity greatest?
Reef crest or just below crest on the fore reef slope
Just below reef crest
What is the length of the Great Barrier Reef system ? The width varies from what to what ? Many what exist along the reef system
1200 miles
10-200
Cayes
Definition of atoll? What may be a part of the atoll structure ?, width variation?
Reef structure surrounding a central lagoon
Sand Cayes
Less than One mile to over 20
Atolls form when what is formed ? The coral begins as what type of reef , what lowers the level of the island over time ?, eventually the island disappears leaving what behind?
Volcanic island
Fringing reef
Weathering and geological activity
Utter band of coral surrounding lagoon
Which atoll has the classic formation ? What is it the site of? What is at the top
Eniwetak
Us nuclear weapon testing
Bomb craters
What does and atoll possess ? The inner slope vs the outer slop and the depth of the lagoon? Where are the two largest atolls
Reef flat and inner and outer reef slopes
Inner more gradual
200 feet or less
Maldives Indian Ocean and Marshall Islands pacific
The water column surrounding the reef is normally very low in? And what is this lack due to ?
Nutrients
Location of the reefs far from sedimentation sources like rivers
Due to low nutrient content the reef does not support the degree of ? The food chain is based around the primary production of ? How does the coral benefit the zooxanthellae ? What does zooxanthellae give to corals
Primary production by phytoplankton seen in other marine communities
Zooxanthellae in body of corals and other organisms
Carbon dioxide , nitrogen,phosphorous (by products)
Organic molecules to corals
Cyanobacteria present on the reef are able to do what? What can also feed reef inhabitants ? Water currents bring what to reef communities
Fix nitrogen which is then available to other inhabitants who feed on cyano bacteria
Sea grasses and algae
Phytoplankton and zooplankton
How can coral reefs deter predators (think producing what?) and is common in what ? These chemicals can be released into?
Producing toxic or foul tasting chemicals
Soft corals and sponges
Water to kill organisms or limit growth surrounding organisms
Other reef dwellers may produce ? To deter ?
Sponges produces spicules of ? Or?
Soft coral produce ? Needles known as ?
Hard structures, predation, spicules, calcium carbonate, silica, calcium carbonate, sclerites
What algae a grown in an encrusting form? What problem does this cause
Coralline, difficult feeding
Tough competition for what in reefs?
Space and light
How do coral limit the competition? What does this do
Growing fast and upright, Maximizes ability of quick reproduction
Another way to limit competition?
Grow slow but massive
Ways that coral feed
Directly or sting each other when come in contact
What other things do corals compete with
Algae, sea grasses, invertebrates
What other organisms compete for limited resources? How do they compete? What do each have?
Fish and crustaceans, feeding in slightly different areas or ways, ecological niche.
What are you bringing Sydney tomorrow ?
Cupcakes
What are you bringing Sydney tomorrow ?
Cupcakes
First two structures that aid in reef building
Coralline algae (also produce calcium carbonate) Soft corals such as sea whips and sea fans
