June 18, 1999
Return to Cox Science Rm 182
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.
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
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
The Role of the Open Ocean in Global Primary
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
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.
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?