CH 5 MARINE EXAM STYE QUESTIONS

Explain why scientists prefer pH neutral cement material to old truck tires, abandoned planes and ships

- coral are very susceptible to reduced pH - they 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 (oil and rust) - pH neutral material allows coral to grow on substrate that is very similar to basaltic rocks it prefers and offers little chance of chemical damage

Suggest 2 reasons why the corals in Key West are not recovering as quickly as those in Islamorada

- given population of Key West, it is possible there is greater tourism preventing a swift recovery - coral may be less sheltered, suffering from pollution (run-off, oil, pesticides) or have been damaged by another storm in the intervening years ( 2 POINTS)

Describe a barrier reef

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

Describe a fringing reef

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

Calculate the percentage increase in coral between 2005 and 2010

[(57-43)/43] x 100 = 32.55%

Describe an atoll

a circular coral reef in the deep waters of the Indo-Pacific with a centralized deep lagoon

Explain which factors are most important when determining placement of a coral reef for healthy growth

- clear water - appropriate depth (20 m or less) so sunlight can reach the zooxanthellae in the coral polyps for photosynthesis - water temperature remains between 23-25 C for optimal growth and reduced stress - hard stable substrate for best attachment

Using data in table, compare the coral cover of both locations between 2000 and 2010

- both locations saw a decrease - however, Key West showed a 25% decrease compared with Islamorada's 19%

Outline the Darwin-Dana-Daly theory of atoll formation

- an oceanic volcano surfaces - hermatypic coral colonise 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

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

- as CO2 in our atmosphere increases, it dissolves more quickly into our oceans through dissolution - once in the ocean, CO2 combines with water to form a weak form of carbonic acid making the ocean more acidic

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

- 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 is increased number of COTS larvae able to survive - if these reach adulthood, they may cause an oubreak

Explain how parrotfish lead to reef erosion

- in order to graze for symbiotic algae parrotfish takes bits of living coral and the limestone skeleton - causes erosion as a result of loss of calcium carbonate

Describe the relationship between butterflyfish and coral polyps

- predator-prey relationship - butterflyfish eats coral polyps

List and describe the 3 reasons why artificial reefs are beneficial to shorelines

- reduce wave height and strength (act as a buffer) - reduce erosion (waves break and expend their energy on the reef lessening its effect on the coastline) - protect coastal developments (coral reefs slow waves that would otherwise break directly on the shore and can be damaging to sea-front property) - protect anchorages for boats - provide economic benefits (saves cost and maintenance of breakwaters) (3 POINTS)

Describe the relationship between coral polyps and zooxanthellae

- symbiotic/mutualistic - both benefit - zooxanthellae give coral carbohydrates from photosynthesis - coral provides nitrogen, phosphorus, and carbon dioxide to zooxanthellae

Suggest 1 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 warm, water and a heavy load of nutrients is not healthy for coral growth