Speed here is of essence and spices like flying fish are able to jump out of water to escape predators. Others that lack like jellies are transparent. Turtles will have a shell to protect them. Gills enable animals to manage different water pressures like the sharks while whales have the capability of holding their breaths for longer periods. On the other hand, since the benthic zone does not allow sunlight to reach it due to its depth (beyond 600 feet), some fish and crustaceans, at this level do not see, in fact half of the species at this level are blind. In this sense, the organisms have adapted to produce their own lights from their specialized parts in their bodies known as photophores. In addition, since there is lack of phytoplacton to start the food chain, life is limited and fish have adapted to fulfill their needs. For instance, some fish have large mouths or guts to enable them consume as much food as possible whenever it becomes available. Others like anger fish have special parts in their dorsal fin to attract prey (Svitil, n.d.). Answer to question 5

The marine ecosystems as are exposed to human interference are definitely prone to different threats. Their effective conservation will all revolve around the appropriate control of natural resources to incorporate marine ecosystems. First considering threat to coral reefs, it or can result from ocean acidification which is a result of the increasing amounts of carbon dioxide in the atmosphere which in turn is absorbed by the ocean. For example, ocean absorbs approximately 525 billion tons of carbon dioxide (CO2). Despite ocean reducing CO2 levels over the globe, it has done so at the expense of marine life. The ocean PH has reduced due to the resulting reactions with CO2 hence unsuitable chemical composition for thriving of coral reefs. To...

In addition, land pollution should be reduced as well as regulated fishing, and adequate public awareness. Considering threats to marine mammal, land based and sea activities result to the available threats. Overfishing is the greatest factor as this affects the food web balance, and when it becomes affected, survival is threatened. In addition, taking sport and commercial fisheries, habitat degradation, sound pollution, algal blooms, oil spills, all affect marine animals such that their either die or flee affecting the food chain. The potential measures to avoid this is to regulate fishing, impose heavy penalties on those who pollute the sea, public awareness on the importance of marine life, and limiting noise pollution at marine ecosystems. About threats to sea turtles, both land based and sea based activities affect the species. Land activities affect nesting while sea activities affect young and grown turtles. The threat is caused generally by loss of feeding habitats, poisoning as a result of pollution and marine debris ingestion, poaching, nest damage and commercial fishing. To manage this, nesting areas should be protected, commercial and sport fishing should be regulated, poaching discouraged and mitigating pollution (Makai, n.d.).
References

Crouse, R. (n.d.). Waves: Tsunamis/Seismic sea waves. Water encyclopedia. Retrieved from http://www.waterencyclopedia.com/Tw-Z/Waves.html

Gardiner, L. (2010, January 8). Surface ocean currents. windows.ucar.edu. Retrieved from http://www.windows.ucar.edu/tour/link=/earth/Water/ocean_currents.html

Lee, H.J., and Normark, W.R. (2009). Earth science in urban ocean: The Southern California continental borderland. New York, U.S.: Geological Society of America.

Makai. (n.d). Threats to marine ecosystems. Waianae ecological characteristics. Retrieved from http://hawaii.gov/dbedt/czm/initiative/wec/html/sea/marine/threats.htm

Svitil, K. (n.d.). Survival beneath the surface. Savage seas. Retrieved from http://www.pbs.org/wnet/savageseas/deep-article.html