A wetland is any area of land that is covered with water for at least part of the year. In Canada, we have freshwater and saltwater wetlands, all of them teeming with wildlife. Some of these include lakes, rivers, marshes, swamps, bogs, fens, muskegs, potholes, flood plains, ponds, puddles, and sloughs. Sadly, wetlands are often wiped out or modified to make way for farmland and housing developments. Others are destroyed by pollution. People even drain wetlands, perceiving them as wastelands. More than 65 percent of Maritime salt marshes, 70 percent of southern Ontario and St. Lawrence Valley wetlands, 40 percent of Prairie wetlands, and up to 70 percent of Pacific estuary wetlands have already been destroyed.
While lakes and rivers act as the blood vessels of our planet, other wetlands behave like the kidneys. Plants and animals living in a marsh break down sewage and many chemicals, leaving clean soil and water behind. Ordinary cattails and bulrushes, for instance, can absorb poisonous heavy metals like lead and mercury. They can also convert fertilizer residues into growing plant parts.
Wetlands work like sponges, soaking up rain and melted snow; this prevents waters from draining off the land and flooding rivers. Ponds and marshes also reduce the risk of erosion during rainy times, and help keep soil moist during dry times. Wetlands conserve water by feeding underground aquifers. In Manitoba, for example, many towns and farms receive deliveries of well-water that are drawn from aquifers.
Aside from providing homes for millions of living creatures, wetlands bring an abundance of dollars into the Canadian economy. Manufacturers and merchants of sporting goods and outdoor clothing receive a lot of money from wetland users. So do owners of cafés, motels, and gas stations. Additionally, billions of dollars are earned annually through agriculture, fishing, mining, manufacturing, and power-generation.
As for water's more indulgent benefits, consider the value of canoeing silently through the reeds on a misty spring morning, or the sight of Canada geese splash-landing on a marsh during a crisp fall sunset. Canada's wetlands are surely one of its most valuable resources.
Use this checklist to identify water problems in your area:
• Oil and petroleum products like gasoline seep into waterways from ships, oil rigs, service stations, and roads. Contaminations of this nature mean a poisonous fate for many aquatic creatures. Oil spills in particular can kill huge numbers of fish, birds, shellfish, and plants.
• Acid precipitation wreaks havoc on wetlands. It changes the pH level, or the degree of acidity in water. Many aquatic plants and animals die if water becomes too acidic.
• Fertilizers running off farms and lawns into waterways cause large amounts of algae to grow on the water's surface. After using up all the nutrients, the algae die and sink to the bottom, where bacteria feed on them. As the bacteria multiply, they use up most of the water’s oxygen, causing aquatic creatures to die. This process is called eutrophication.
• Wastes dumped into water from paper mills or treatment plants are also eaten by bacteria. Eutrophication may result.
• Chemical pesticides are designed to kill or control unwanted bugs, but are not selective and kill beneficial insects as well. Unfortunately, irrigation, water flow, and natural run-off wash these poisons into water. Many are toxic to fish and harmful to people as well.
• Chemicals, minerals, solid matter, and metal salts from mining or industry can wipe out fish and other aquatic creatures.
• Temperature changes to water caused by electric power plants can cause harm too. These operations also use large amounts of water for stream turbines.
• Soil, clay, sand, and minerals can wash into water from land and paved surfaces. These sediments suffocate fish and shellfish by clogging their gills and smothering their nests. Large construction projects and some logging operations can dump huge amounts of sediment into lakes and rivers.