June 18, 1999              Return to Cox Science Rm 182                   2nd Edition
Due: Wednesday, June 23, 1999

Estuaries in Serious Decline: Economies Suffer
Estuaries throughout the United States have experienced a serious decline in water quality which has had a dramatic affect on some of the important marine species which live in these normally productive areas. Places as diverse as Boston Harbor, Chesapeake Bay, Florida Bay, San Francisco Bay and Seattle Bay have experienced massive fish kills and algal blooms as well as untreated sewage and industrial wastes washing up on the shores. The ability of estuaries to dilute, disperse and degrade our waste has been overwhelmed by the sheer amount that has been dumped in these waters. Question 1. What classes of pollutants are usually discharged into estuaries? What factors are involved in determining how an estuary will be affected by waste discharge?

Ocean Primary Productivity Threatened by Global Change

Ocean scientists around the world have expressed concern over the effects of runaway greenhouse warming on the primary producers of the oceans, the microscopic phytoplankton. Primary production in the world's oceans varies latitudinally and seasonally. Question 2. Compare the annual productivity of polar, temperate and tropical ocean regions. What abiotic factor(s) generally limit productivity in each area?

The Role of the Open Ocean in Global Primary Production

The rate of primary production in the open ocean is lower than the rate of primary production along the coasts, but the total primary production of the open ocean is greater than that of the coasts. Question 3. Explain this apparent contradiction. Why are coastal areas more productive than the open ocean?

The Tragedy of the Oceans

"Plenty more fish in the sea" runs the saying. But it is wrong. The sea's abundance has been stretched beyond its limit. In the past decade, most of the worlds rich fisheries stocks have been fished out. The Canadian Ministry of Fisheries has recently imposed a ban on fishing in Canadian waters on the Grand Banks in the North Atlantic. The major catch in this area is the cod, a fish that produces nearly a million eggs during the breeding season. Despite the high reproductive capacity of the cod, the population has dwindled over the years to the point where cod stocks are severely depleted. Scientists and fisheries managers point to several reasons for the collapse of the cod fishery and hope that the ban will allow cod to replenish the once abundant stocks. Question 4. What factors are responsible for the depletion of the cod in a relatively short period of time? Discuss your answer from both a management and biological perspective.

Feeding Lower on the Food Chain

One result of the decline of fisheries is that fishermen are targeting less desirable species to harvest. A study of catch statistics over the past decade has shown decrease in the average trophic level which the fish occupy. This shift in the food webs of the ocean is predicted to have long term consequences on the stability of marine communities. Question 5. Explain how overharvesting fish near the bottom of the food web can affect higher trophic levels.

Global Decline in the Health of Coral Reefs Reviewed By Scientists

The health of coral reefs is declining on a global scale. Most dramatic impacts are seen in areas of high population density along the coasts of less developed nations. However, even here in Florida, population, develop-ment and overuse are responsible for a decline in the reefs of the Keys. Question 6.What are the major anthropogenic (human) impacts on coral reefs and how do they affect the health of reef ecosystems? Why do you think it is important to preserve coral reefs?

Where do you fit in?

As a student of oceanography, hopefully you have gained some insight into the importance of the oceans in the functioning of the planet and as a source of food, energy and resources. You have also probably appreciated the aesthetic value of sitting under a palm tree on a deserted beach contemplating the vicissitudes of life. Question 7. How has your understanding to the oceans changed during this course?As a solid citizen and a person interested in the future of the planet, how can you as an individual contribute to the protection and conservation of our oceans?