coral reefs and lagoons

suggest a reason why surfers at popular surfing locations may protest against the installation of an artificial reef designed to protect the shoreline

surfers tend to like large waves to surf on. artificial reefs are designed to reduce wave height and power, making the waves less fun to surf

describe the relationship shared by coral polyps and zooxanthellae

this relationship is symbiotic/mutualistic because the zooxanthellae give the coral carbohydrates from photosynthesis and the coral provides nitrogen, phosphorus, and carbon dioxide to the zooxanthellae, creating a benefit to each

suggest one reason why coral reefs are not usually found in upwelling areas

upwelling is the rise of cold, nutrient-rich water to the surface. both the presence of cold, instead of not warm, water and a heavy load of nutrients is not healthy for coral growth

list and describe three reasons why artificial reefs are beneficial to shorelines

-reduce wave height and strength -reduce erosion -protect coastal development

describe an atoll

a circular coral reef in the deep waters of the indo-pacific with a centralized deep lagoon

describe a barrier reef

a reef separated from land by a lagoon that may be many kilometres wide

describe a fringing reef

a shallow reef that forms along a coastline, with little or no lagoon

outline the Darwin-Dana-Daly theory of atoll formation

an oceanic volcano surfaces; hermatypic coral colonize the coastline of this volcano; this volcano begins to sink as a result of subsidence, causing vertical growth of the coral reef and the development of a lagoon between the reef and the shore; the volcano continues sinking until it is below the surface and all that remains is a circular reef with a central lagoon

explain the role of artificial reefs in the preservation of shorelines

artificial reefs work to protect the shoreline by creating a natural breakwater. by slowing down waves and reducing their height, the artificial reef is able to reduce the amount of sand the water is able to hold thereby preserving the shoreline

describe how increased carbon dioxide in our atmosphere is related to ocean acidification

as the carbon dioxide in our atmosphere increases, it dissolves more quickly into our oceans through dissolution. once in the ocean, carbon dioxide combines with water to form a weak form of carbonic acid making the ocean more acidic

explain why coral reefs are most commonly found within 30 degrees north and south of the equator

coral reefs are most commonly found between 30 degrees north and south of the equator because these tropical waters have the warmest temperatures, low levels of nutrients and clear waters

most artificial reefs are now constructed from a pH neutral cement material. explain why scientists prefer this material to old truck tires, abandoned planes and ships

corals are very susceptible to reduced pH and tend to do best in a slightly basic environment. truck tires, planes and ships all contain chemicals that may alter the pH or contaminate the water (ex. oil and rust). therefore a pH neutral material allows the coral to grow on a substrate that is very similar to the basaltic rocks it prefers and offers little chance of chemical damage

how are modern scientists using carbon dating and deep drilling to support early theories like the Darwin-Dana-Daly theory of atoll formation

deep drilling allows scientists to take core samples from corals that can show the different species that have inhabited the reef over time. the results of carbon dating the corals in the samples support the theory that the oldest corals are the deepest. these data provide evidence supporting the Darwin-Dana-Daly theory of atoll formation.

in order to determine the best placement for artificial reefs, developers must take certain physical factors into consideration. explain which factors are most important when determining placement of a coral reef for healthy growth

for healthy coral growth, developers must place artificial reefs in clear water of appropriate depth (20 m or less) so sunlight can reach the zooxanthellae in the coral polyps for photosynthesis. they must also ensure the water temperature will remain between 23-25 degrees for optimal growth and reduced stress and that coral will have a hard stable substrate for best attachment

explain how parrotfish lead to reef erosion

in order to graze for the symbiotic algae, parrotfish take bites of living coral and the limestone skeleton. this causes erosion as a result of loss of calcium carbonate

summarize the evidence used to support the Darwin-Dana-Daly theory of atoll formation

the evidence used to support the Darwin-Dana-Daly theory of atoll formation comes primarily from the fossilized coral existing at the very bottom of atolls. because healthy coral growth happens with 20 m of the surface, these fossilized corals indicate that at one time the surface was much closer. the best explanation for fossilized corals at the base of a coral reef 1200 m deep is that the land has slowly sunk into the seabed, taking the coral down with it.

explain how limiting nutrients, such as nitrogen and phosphorus, can have both negative and positive impacts on coral growth

the impacts of limiting nutrients on coral is all relative to the amount present in the environment. when the levels of nutrients are in balance, zooxanthellae are able to grow well and provide corals with more nutrients to build their skeletons. when the concentration of nutrients is too high, it leads to a plankton bloom. a plankton bloom can cause turbidity in the water preventing sunlight from reaching zooxanthellae and reducing photosynthesis thereby lessening the availability of energy to coral. another side effect of increased nutrients is the increased number of crown-of-thorns starfish larvae able to survive due to an increase in food source (phytoplankton). if these reach adulthood, they may cause an outbreak

describe the major factors leading to reef erosion

the major factors leading to reef erosion include predation by animals like the crown-of-thorns starfish, damage from tropical cyclones, exposure to air at low tides and ocean acidification

suggest which physical factors are linked most closely with the symbiotic relationship coral has with zooxanthellae. support your answer with evidence

the physical factor linked most closely with corals symbiotic relationship is sunlight. the zooxanthellae need sunlight in order to photosynthesize. the products of photosynthesis are then given to the coral, allowing it to have enough energy to build its coral skeleton, so creating the reef. other factors tied to sunlight are reef depth and water clarity

compare and contrast the three major types of reefs: fringing reefs, barrier reefs and atolls, paying particular attention to formation and age

the youngest of the reef types is the fringing reef, which forms early along the edge of an oceanic volcano. if present, the lagoon in a fringing reef is very narrow, unlike those of the slightly older (geologically speaking) barrier reefs that tend to have deeper and wider lagoons. atolls tend to form a circular pattern with a lagoon in the center that can be very wide and deep. they form far away from land and tend to be the oldest of the reefs.

describe the relationship shared by butterflyfish and coral polyps

this is a predator-prey relationship because the butterflyfish eats the coral polyps