Thursday, May 12, 2011

Planet's Got Deep Blue Trouble

Representing over 75 percent of the Earth’s surface, the ocean has long been thought to be resistant to health woes because of its ability to absorb human waste and pollution.

The ocean’s sheer volume seemed to support the notion of “dilution is the solution” to point-source contaminants. The premise: Tides and currents removed almost anything that entered the sea.

But added pressure on the marine environment – increases in human population, industry, and agriculture – has led to concerns that the ocean’s health is being harmed by human activities.

Indicators Tell Story

The ability of scientists to monitor the ocean’s health is hampered by its complexity, according to Robert J. Taylor of the University of Florida.

Although the basic chemistry of sea water has been stable for millions of years, components such as nutrients and dissolved oxygen directly affect plant and animal life.

Living populations vary naturally because of interactions between oceanic and atmospheric processes.

Evaluating the health of the planet’s oceans therefore requires that human impacts must be distinguished from a natural, changing background.

Techniques for evaluating oceanic health include estimates of commercial fishery populations and localized studies of plant and animal species.

Impacts from contaminants and adverse water quality ideally are monitored through long-term baseline studies.

In the United States, this approach has been followed by the National Oceanic and Atmospheric Administration’s Mussel Watch program.

The study focuses on organic and inorganic contaminants in mussels and oysters in U.S. coastal waters. The success of this approach has led to similar studies on an international scale.

Historical trends of contaminant input have been evaluated through “dated core” studies in which contaminants are measured in marine sediment layers and compared with estimates when they were deposited.

Larger special scales are evaluated by remote sensing to measure a variety of variables such as temperature, plankton populations, and sediment load of surface waters.

Some Major Threats

Pollution, habitat change, and overfishing are considered the major threats to oceanic health.

Pollutants include chemicals, sewage, floating debris (for example, plastic and trash), and nutrient elements (for example, nitrogen and phosphorus) released to coastal areas either directly, via rivers, or via the atmosphere.

Oceanic health is impacted almost everywhere by alteration or destruction of critical ecosystems.

These changes include the erosion and loss of all salt marshes; drainage of wetlands; siltation of estuarine areas after deforestation and erosion; alteration of fresh-water inputs; and restriction of fish migration routes by dams.

Dredging, boating, and pressure from tourism are deteriorating coral reefs around the world.

Overfishing target species, such as whales and sharks, and the accidental removal of non-target species are damaging overall ocean health.

Many fish populations have declined dramatically as a result of overfishing.

What Holds Water

Although human population and development in coastal areas continues to expand, releases of chemical contaminants and nutrients will still be regulated in developed countries.

Lessons learned in developed countries continue to help oceanic health around the world. This will enable the improvement of economies and infrastructure while preserving natural environments.

WMB believes that difficult policy innovations are required to restore and conserve ocean habitats to earlier conditions.

Growing populations dependent on fisheries as protein sources, especially in developing countries, makes this lifestyle especially important.

WMB further supports the theory that economic survival provides the impetus for maintaining and improving marine environmental conditions.

By example, fishermen need to optimize their costs per unit catch.

This could require government intervention in the form of subsidies; this is particularly important to maintain ocean-based tourism and coastal habitats for future generations.


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