Although large areas of the Yukon remained ice-free during the Pleistocene, the remainder of the western Canadian arctic was glaciated. Many of the deeper lakes (> 20 m) were created by glacial scour or morainal damming of mountain valleys. Kettle lakes and oxbow lakes are common in areas of low relief such as on the Mackenzie River Delta.
Tax subsidies are the result of selective tax legislation that benefit particular groups of people or industries in the economy. In effect, they share the costs of certain actions between the private sector and the government and impact investment decisions by increasing the expected returns associated with a particular pattern of economic activity.
An important factor influencing the productivity of our planet’s various ecosystems is the nature of their soils. Soils are vital for the existence of many forms of life that have evolved on our planet. For example, soils provide vascular plants with a medium for growth and supply these organisms with most of their nutritional requirements.
The total global industrial consumption of lead in 2003 was estimated to be 15.1 billion pounds, and the U.S. consumption of lead in 2003 was estimated to be 3.06 billion pounds. The greatest use of lead is in lead-acid batteries, however lead-acid batteries are not manufactured in Massachusetts.
Even the largest coral reef and the biggest coral colony start life as a diminutive pelagic larva, and the choices that such larvae make with regards to where they settle have consequences that cascade through the entire reef ecosystem.
The nitrogen cycle represents one of the most important nutrient cycles found in ecosystems. Nitrogen is a required nutrient for all living organisms to produce a number of complex organic molecules like amino acids, the building blocks of proteins, and nucleic acids, including DNA and RNA.
Permafrost is soil, rock, sediment, or other earth material with a temperature that has remained below 0°C for two or more consecutive years. Permafrost underlies most of the surfaces in the terrestrial Arctic.
Historically, human actions have been inconsequential on the forces of nature, however, humans are now influencing the processes of the planet. The water bodies of Canada and the world are being invaded by non-native or exotic species.
