Sea sickness: global warming, pollution, and other human activities are causing problems everywhere in the world's oceans.

There are plenty of signs that all is not well ,with our planet's biggest ecosystem:

* Pollution is changing the chemistry of seawater;

* Between 1992 and 2000, the portion of coral reefs that has been severely damaged from direct human pressures and global warming climbed from 10 percent to 27 percent;

* The world has lost half its coastal wetlands, including mangrove swamps, and salt marshes;

* Many of the oceans' top predators, such as sharks, have suffered catastrophic population declines during the last 15 years;

* Human activities are eroding close to 70 percent of the world's beaches at greater than natural rates;

* Two-thirds of marine mammals are now classified as threatened species.

There are many other indicators that disturb the sleep of oceanographers, and the place to see their most dramatic effects is where the water meets the people. Coastlines are threatened almost everywhere on the planet.

More than half of the world's 6.4 billion people live within 60 kilometres of a shoreline. Humans have concentrated their settlements near coastlines because of the productivity of water. Natural systems such as salt marshes, mangrove forests, coastal wetlands, coral reefs, oceans, and river estuaries confer enormous benefits on us. Their continued health is vital to our survival all other life forms on the planet.

However, we've been using the oceans as a place to put stuff we don't want. Here's just one small example. The city of Halifax, Nova Scotia has flushed its untreated sewage into the harbour for centuries. In 2004, it finally began building a sewage treatment system that will be finished in 2008. Until then, the city will continue dumping 16 million litres a day of raw sewage into the harbour. And, this is happening in one of the richest and most highly developed nations in the world.

In many parts of the developing world, where population growth is exploding in coastal cities, "frills" such as sewage treatments are simply unaffordable. As a result, 90 percent of sewage is released untreated into surface waters in the developing world. The sludge pollutes aquifers, freshwater resources, and coastal areas. People develop an estimated 250 million cases of gastroenteritis and upper respiratory diseases each year from swimming in contaminated seawater.

Along with massive quantities of human waste, we toss far more dangerous swill into the oceans--persistent organic pollutants (pesticides, dioxin, PCBs), heavy metals, oils, acids, and an alphabet soup of other toxic-chemical wastes. Even radioactive material ends up sitting on the ocean floor.

Today, there are rising levels of cancer-causing agents in the fish we eat, and an increasing number of beaches are off limits because of water-borne contaminants.

Municipal, industrial, and agricultural wastes and run-off account for some 70 to 80 percent of all marine pollution. Waters around many coastal cities have turned into virtual cesspools. They are so fouled by pollution that almost no marine life can survive:

* Despite more than two decades of cleanup efforts, the Mediterranean Sea still receives between 30 and 50 million tonnes of untreated or partially treated sewage every year;

* Calcutta and Mumbai (Bombay), India, respectively, dump 400 million tonnes and 365 million tonnes of raw sewage and other municipal wastes into coastal waters annually;

* The Lagoon of Iddo in Lagos, Nigeria, gets a yearly dollop of 60 million litres of raw sewage, along with vast quantities of industrial waste;

* Industrial filth and sewage at the rate of 175 million tonnes a year goes from Karachi, Pakistan into the Arabian Sea;

* Among other recipients of goop in the millions of tonnes range are the Yellow Sea of China, the Bays of Concepcion and Valparaiso, Chile, and 146 "dead zones" that researchers identified around the world's coastlines in 2004.

Anybody up for a swim?

There's a huge dead zone in the Gulf of Mexico. It covers an area of about 21,000 [km.sup.2], and it's getting bigger all the time. As a result of pollution from rivers flowing into the Gulf the level of dissolved oxygen in what passes for water is too low to support any form of marine life. But even this large dead zone is dwarfed by one in the Baltic Sea. This giant covers 70,000 [km.sup.2], an area almost as big as the province of New Brunswick.

While the worst pollution is found close to where it is dumped, no area of the world's oceans is unaffected. Currents carry the poisons to remote corners. Toxic chemicals such as DDT and PCBs are found in the bodies of Arctic seals and Antarctic penguins. The animals have not been within thousands of kilometres of places where these substances are used.

More than half the world's coastlines are suffering from "severe development pressures." This is the conclusion of a study by the World Resources Institute (WRI) in the mid-1990s. The WRI study used four key indicators to assess risk to coastal areas: cities and population density, major ports, road density, and pipeline density. According to these indicators, the coastlines of most developed countries were suffering from development pressures and loss of coastal resources. But, developing countries fared little better--around virtually all urban areas, shorelines and their fragile environments are threatened by toxic wastes and too much construction.

Around the world, coastal wetlands have been devastated. During the past century an estimated 25 million hectares of mangrove forest has been destroyed or grossly degraded.

No big deal we might say; mangrove swamps are nasty places--hot, snake-infested, impenetrable, and buggy. But, what is a horrible place for humans is paradise for about 2,000 species of fish, shellfish, insects, invertebrates, and plants. Knock them out of the food chain and there is a big impact among other species, including our own.

Mangrove swamps protect coastal areas from erosion and storm damage. They filter and clean up human and industrial waste, and we've seen how badly needed that service is. The mangrove makes a perfect nursery for fish. The tangled roots give protection from predators and allow the fish to reach adulthood in safety. Then, they can venture out to breed and, perhaps, become supper for fisher folk and their families.

But, all over the world's tropical regions mangrove forests are getting whacked down. They are making way for aquaculture projects, road building, and the spread of towns and cities. In tourist areas, the big demand is for luxury resorts and condos, not mangrove swamps.

According to the United Nations: "During the last three decades, 25 percent of mangroves in Malaysia, and 50 percent of mangroves in Thailand have been lost." The global loss of mangroves has been estimated to be at least 35 percent and possibly as much as 50 percent.

Experts believe this destruction played a role in the death toll from tsunamis that struck Indian Ocean coastlines on Boxing Day 2004. M.S. Swaminathan is chairman of an Indian government inquiry into coastal developments. He told The Guardian (U.K.) that, "Where [mangrove] forests have been cut down and there is sand mining and developments, the devastation is more widespread. The dense mangrove forests stood like a wall to save coastal communities living behind them."

Coral reefs also defend coastlines from ocean damage, and they are going the way of mangrove swamps.

Biologists call coral reefs the "rainforests of the oceans," because of the rich diversity, of life found within them. They support upwards of one million species and provide humans with many benefits. They reduce the power of waves and protect shorelines from erosion; they provide feeding, breeding, and nursery areas for many commercially important species of fish and shellfish; and, they offer scientists a rich storehouse of potential medicines.

Unfortunately, these rainforests of the ocean are suffering the same fate as rainforests on land and are becoming coral griefs.

There are about 600,000 [km.sup.2] of reefs (that's an area almost the size of Saskatchewan) found in tropical and semi-tropical seas. Scientists estimate that 70 percent of these reefs could be lost within 40 years.

Why such massive destruction? Global warming appears to be the main culprit. Coral reefs are living organisms and a rise in ocean temperatures, even just one degree Celsius, has a devastating effect. In November 2002, scientists led by Thomas Goreau, President of the Global Coral Reef Alliance, grabbed the world's attention by declaring that, "this year more coral died of heat stroke than from all human causes to date ever."

According to a 1997 study by Hong Kong University, the Caribbean Sea had the lowest rate of living coral. Less than a quarter (22 percent) of that region's coral reefs were in good or excellent condition. Southeast Asia was second, with only 30 percent of its coral reefs in good to excellent condition.

But, humans are also destroying coral reefs in a more direct way from a couple of strange "fishing" methods. One is to drop a stick of dynamite over the side of a boat. The explosion kills fish, which float to the surface for easy capture. The shockwave also blows the coral apart.

A second method is used by divers. They squirt a shot of sodium cyanide solution at chosen fish. The poison stuns the fish but the overspray kills coral. The fish is taken to swim around in a large tank in a restaurant where diners can pick out their dinner while it's still alive. This trade is said to generate $40 million a year out of Manila, capital of the Philippines, alone. Up to 80 percent of the coral reefs around the Philippines are said to be dying.

Coral reefs, says Thomas Goreau, are becoming "the first ecosystems to suffer large-scale damage from climate change." Global warming, if unchecked, is "condemning all coral reefs to death." The coral is also being impacted by the changing chemistry of ocean water.

When the Industrial Revolution picked up steam at the end of the 18th century, the concentration of carbon dioxide (C[O.sup.2]) in Earth's atmosphere is estimated to have been 280 parts per million. The growth of industry meant the burning of fossil fuels--coal at first, and then oil and gas--for energy. A byproduct of the energy production is carbon dioxide, which has now grown to an atmospheric concentration of 380 parts per million.

The amount of C[O.sup.2] would be higher if it wasn't for the ocean's ability to absorb it. However, this absorption is changing the chemistry of seawater and this is slowing the growth of plankton, corals, and other tiny sea creatures that serve as the most basic level of the ocean food chain.

Marine chemist Richard Freely is one of the scientists who have studied this. He says that, "Because carbon dioxide is an acid gas, the surface ocean pH is dropping" (pH is a measure of acidity in solutions; the lower the pH, the more acid a liquid is). Some types of mollusks, plankton, and coral can't survive in acidic conditions. Satellite surveys have detected a sharp decline in plankton in several of the world's oceans--a situation that could threaten the marine food chain and undercut one of the world's natural buffers to global warming.

In 2002, National Geographic magazine reported that there had been a 30 percent drop in phytoplankton (microscopic plants) in the North Pacific since the 1980s. There was a 14 percent decline in the North Atlantic Ocean.

Scientists are divided about both the cause and the effect of this change.

The plankton may be dying as part of a natural cycle or because of global warming. As to the effects, there is agreement that they are not likely to be good.

For one thing, the phytoplankton absorb about half the greenhouse gasses thought to be a cause of global warming. Losing this major source of carbon dioxide neutralization will cause global warming to increase. This will likely kill more plankton in an accelerating cycle.

This is bad news for humans. It's even worse news for the marine life that feed on plankton. Among those are shrimp-like creatures called krill, which, in turn, are the main diet of many fish and marine mammals including whales.

Off the coast of southern California there was a 45-year-long decline in plankton. This caused a collapse in the sardine population and the fishery it supported. There has also been a tumble (by 90 percent) in some sea birds such as the sooty shearwater and other species of commercial fish--anchovy, mackerel, and rockfish.

Scientists at the Scripps Institute of Oceanography are puzzled. They say they don't know for sure why the plankton took such a hit, nor if this is related to other population declines. This highlights the point that there is far more that we don't know about the oceans of the world than what we do know.

However, one major research project shows what can happen. Dr. James Estes of the U.S. Geological Survey has spent many years studying sea otters in the North Pacific. In the 1990s, the numbers of these marine mammals started to plummet. Dr. Estes and his colleagues traced the cause to a decline in plankton, a classic case of one thing leading to another.

The disappearance of plankton led to a drop in the ocean perch and herring they sustained. Less nutritious pollock moved in to replace the declining species. Seals and sea lions started to drop in numbers, probably because the pollock were not rich enough to sustain them as herring and perch had. Orcas, which fed on seals and sea lions, had to look elsewhere for their meals. Sea otters proved to be a tasty substitute. Their population dropped by 90 percent and in some places they have vanished without a trace.

With the sea otters gone, other things started to happen. Otters love to eat the sea urchins that live in kelp forests--vast fields of seaweed. The sea urchin population exploded and devoured the kelp forests. Of course, scores of other species--sea birds, mussels, many small fish--depend on the kelp for survival. All of which proves the interconnected nature of the world's oceans.

SUGGESTED ACTIVITIES:

1. In 2003, biologists at Dalhousie University in Halifax reported a sudden decline in the population of sharks. In the Northwestern Atlantic Ocean hammerhead shark numbers dropped 89 percent since 1986," thresher sharks were down 80 percent, white sharks 79 percent, and tiger sharks 65 percent. Sharks are the top predators in the ocean food chain and their disappearance has a profound effect on the web of life. Appoint a team of students to research the impact of the loss of top predators on ecosystems. A good starting point is--http://www.conservation institute.org/predators.htm.

2. Draw a schematic showing how life forms in the oceans and out of it depend upon each other for survival.

3. A great many of the problems with oceans seem to be related to global warming. Whether or not this is caused by humans, human activity is certainly contributing to it. Have students discuss what they are doing as individuals to reduce their contribution to global warming.

CRY FOR KELP

Most of us eat kelp regularly by consuming ice-cream or jelly. A substance extracted from this type of seaweed is used to thicken these foods and other products such as toothpaste. Pharmaceuticals, cosmetics, and paper are some other products that use kelp.

Kelp grows in cool, coastal water. Tall fronds, anchored on the seabed, reach up to the surface; the plants may grow as much as 50 centimetres in a day and reach a length of 35 metres or more. Kelp grows in forests that cover wide areas and provide a rich habitat for hundreds of species.

As with many other forms of ocean life, kelp is threatened. One area where kelp forests have suffered badly is around the island of Tasmania of the south coast of Australia. The size and number of giant kelp beds in Tasmania has fallen dramatically over the last 30 years. Only about five percent of the original area remains, and the kelp forests are threatened with local extinction in some parts. Scientists think that a number of factors may be causing this decline:

* Over-harvesting in some areas;

* The fall of dissolved nutrient levels in the ocean waters of Tasmania; and

* An increase in water temperature off eastern Tasmania: a rise of 1.5[degrees]C since the 1960s.

CRUISING

Huddled against wind-chill of minus 40 who wouldn't rather be lounging on the deck of a cruise ship in the Caribbean Sea? The answer is that most of us would choose the Windward Islands over the wind-chill.

The Caribbean Region, stretching from Florida to French Guiana, receives 63,000 calls from cruise ships each year. The average cruise ship carries 600 crew and 1,400 passengers. About 400,000 people cruise the Caribbean Sea every month. Those vacationers produce a lot of waste; an average of 3.5 kilos of garbage each per day.

Not so long ago, much of this, in addition to some really yucky stuff, went over the side of ship. Then came the International Convention for the Prevention of Pollution from Ships. Approved in 1973 and amended in 1978, if is called MARPOL 73/78. However, it seems to have taken some hefty fines to get some cruise lines to pay attention to its rules.

In 1993, Regency Cruise Lines was hit with a quarter of a million dollar fine for discharging waste at sea. Earlier, Princess Cruises was dinged for half a million dollars for dumping plastic bags: the passenger who videotaped it doing so was awarded half the fine.

Today, cruise ships being built have their own waste treatment plants and recycling facilities. Most of them have higher standards of sanitation than the Caribbean countries they visit. And, that is another problem. Eventually, treated sewage and garbage has to be brought ashore. There is little benefit to the environment if countries can't handle if properly when it's delivered to them. Authorities are working on this.

LIFE IS A BEACH

Beaches are Nature's protection against coastal erosion. However, the World Resources Institute says that, "human activities are eroding close to 70 percent of the world's beaches at greater than natural rates. Coastlines in developing countries are suffering from serious erosion problems due to unplanned coastal construction, dredging, mining for sand, harvesting of coral reefs for building material, and other activities."

Beaches in West Africa have been particularly hard hit. Hundreds of coastal villages have been moved inland as the sea advances. In the Niger River Delta, for instance, erosion claims 400 hectares of land a year and 40 percent of the inhabited delta could be lost in 30 years.

In Togo, the construction of a port in the late 1960s has destroyed beaches. A long jetty was built to block waves and create calm water for ocean-going ships. But, the waves carried sand to beaches along the shore. Robbed of the replenishment of sand, these beaches have become bare rock.

The traditional fishing method was to cast nets from the beach and haul them in. But, pulling nets over bare rock cuts them to shreds. There used to be 64 fishing villages in the area: today, there are 22.

FACT FILE

Coral reefs are among the oldest and largest living entities on Earth. Vast numbers of other creatures live in them--including an estimated quarter of all the world's sea fish.

The Gulf Stream moves more water from the Gulf of Mexico and the Caribbean across the Atlantic into northern Europe than is carried by all the rivers on Earth combined.

FACT FILE

Ocean industries contributed about $23 billion to Canad's economy in 2000, but this represents only about 1.5% of the country's Gross Domestic Product. The equivalent of about 150,000 full-time jobs in Canada are directly related to ocean industries. The fishing industry is the largest employer, but many of the jobs are part-time.

FACT FILE

Only five percent of the ocean bottom has been properly mapped,

Websites

Global Coral Reef Alliance--http://globalcoral.org/

Protection of Marine Environments--http:// padh.gpa.unep.org/

Scripps Institution of Oceanography--http:// sio.ucsd.edu/