Rivers to Oceans fact sheet

• Oceans provide 97.5 per cent of the Earth's water and cover approximately 70 per cent of its surface.
• Eighty per cent of ocean pollution is caused by human activity on land. Marine debris, such as plastic bags, lost fishing gear, six-pack rings, and glass bottles, remain in the environment for years, killing or injuring right whales, leatherback turtles, and numerous other seafarers, that become entangled in the litter or mistake it for food.
• Oceans, including their bottom sediments, are the largest carbon storage areas on the planet. Water helps us fight climate change by storing much of the Earth’s carbon supply in soils, terrestrial plants, undisturbed petroleum deposits and oceans.
• Billions of litres of untreated sewage flows into our waterways. This includes motor oil, solvents, and miscellaneous toxic chemicals; inadequately treated waste water from industries; pesticides sprayed on gardens and crops; nutrients, such as phosphates and nitrates from municipal and agricultural sources; and human waste, which often contains pharmaceuticals,. Marine pollution affects estuaries and coastal waters, areas critical to migratory species.
• Water is good for our health in more ways that one. Anti-leukemia drugs have been developed from sea sponges, bone-graft materials have been made from coral, and anti-infection agents have also originated from the sea. Kelp, for example is an anti-oxidant, and the algin from kelp is used to make ice cream, drinks, medicines, paper, cosmetics, ceramics, paint and other substances.
• All water is essentially reused and the Earth’s water is in constant motion through the hydrological cycle. Since time began, the same amount of water has splashed around in an everlasting circle. It begins when the sun's heat changes water to vapour (evaporation). Plants also give off vapour through their leaves. Then, when the vapour cools, it falls to Earth as rain, snow or sleet. The oceans play a huge part in this cycle: each year, about 330,000 cubic kilometres of water evaporate from oceans! (The salt stays behind, by the way).
• Rain, snow and fog can become acidic when they pick up chemicals from the surrounding air. Few underwater species can survive continued immersion in an acidified lake. When a lake is fed too many nutrients, such as nitrogen and phosphorous (found in fertilizers, sewage and soaps), an explosion of plant growth occurs. These plants eventually die and, as they decompose, they use up the oxygen and warm up the water. Fish that require lots of oxygen (lake trout, for example) can no longer survive.
• Nature-based tourism is estimated to contribute $12 billion per year to Canada’s economy.  One-third of Canadians enjoy water-based activities like swimming, boating, canoeing, fishing, kayaking and camping.
• There are more than 900 dams that are 10 metres or more in height throughout Canada. These obstacles prevent fish and other aquatic species from traveling to essential feeding and spawning grounds. They often result in unnaturally low water levels that can leave some species (or their eggs) high and dry.
• Water temperature is one of the key characteristics that determines “who” can live “where” in rivers and oceans. As the climate gets warmer, water also warms up. In freshwater systems this can mean greater evaporation, lower water levels, and less available oxygen. (
• The effects of oil spills on wildlife are splashed across the headlines on a far too regular basis and the risks of a spill increase as we extend our search for crude oil into underwater habitats. Every year, more than 300,000 birds are killed by oil off the south coast of the island of Newfoundland alone.
• Cod has been continuously fished on the Grand Banks by many nations and in great numbers since the 1400s but due to overharvesting and a rapid population collapse, fishing for cod within Canada’s waters was closed in 1995. When we harvest more fish, shellfish or plants than nature can replace, the population crashes. The tragic tale of the Atlantic cod is a sad example of the dangers of overharvesting.
•  Some ocean-going trawlers drag their nets along the ocean bottom, killing most of the fish and mollusks in their paths, destroying reefs, and stirring up mud that clogs the gills of other species in the area. While these fishers may be seeking only a few species, many other underwater creatures fall as casualties to their destructive methods.
• Humans sometimes bring new aquatic species to an area on purpose or through carelessness. If these newcomers take hold, they often replace native species. Zebra mussels, originally from Russia, are a well-known freshwater example. Since they were first found in Lake St. Clair in 1986, they have rapidly spread to all the Great Lakes and beyond. They filter about one litre of water per day, removing the phytoplankton that drives the entire food web. There are now enough zebra mussels in Lake Erie to filter the entire volume of the lake once a week and to deprive other species of a share in the food supply.
• When freshwater or ocean shorelines are disturbed, soil is added to the water. Think about trying to breath in a dust storm. That’s what underwater creatures go through in muddy waters.