Resources and Our Environment

Environmental Resources Earth's environment includes all of the resources, influences, and conditions at Earth's surface Vital resources to life: air, water, land, and sunlight Vital economic resources:coal and oil, metal ores Renewable resources can be replaced in nature at a rate close to the rate of their use, such as → oxygen, trees, food grown in soil, solar energy Nonrenewable resources exist in a fixed amount or are used up faster than they can be replaced in nature → metals: gold, silver, iron, copper, and aluminum. → nonmetals: sand, gravel, limestone, sulfur → energy sources: coal, oil, natural gas, uranium

Air Air is a renewable resource 78% Nitrogen, 21% Oxygen, 1% argon, carbon dioxide, and other gases Respiration: the process by which oxygen is combined with food molecules to produce energy, water and carbon dioxide Photosynthesis: the process by which plants use light to convert carbon dioxide and water into sugars and oxygen

Air Pollution Pollution occurs when some part of the environment is changed in a way that makes it unfit for human, plant, or animal use Air picks up chemicals or particles called pollutants Most potential pollutants come from human activities Sulfur dioxide comes from burning fossil fuels, and causes acid rain Many gases produced in vehicles are poisonous Natural sources of air pollution include forest fires, dust from soil, pollen, volcanic eruptions, and sea spray

Land and Soil ~ 29% of Earth’s surface is land How humans use land depends on steepness, climate, and soil conditions Soil is a mixture of mineral matter, decaying organic matter, water, air, and living organisms Soil fertility is the ability of soil to grow plants Less that 25% of the Earth’s land can be used to grow crops

Problems in Land and Soil Use When the rate of erosion exceeds the rate of topsoil formation, the soil becomes a nonrenewable resource Erosion is most prevalent on steep slopes where plants have been removed Topsoil is renewed at a rate of a few inches every decade Soil depletion removes nutrients from the soil Salinization is caused by the evaporation of water, leaving behind dissolved salts Land is a limited resource, there is only so much available

Water Over 70% of Earth’s surface is covered by water, 97% in the oceans Ocean water is too salty for growing crops or for drinking Most uses of water require fresh water from lakes, rivers, and groundwater The water cycle replenishes the fresh water Quantity of water is a challenge Quality of water is also a challenge

Water pollution Pollution from industrial waste and domestic waste increases the pressure on water supplies Pesticides, sewage, oil leaks and spills, and contaminated water all find their way into the water supply Phosphates and nitrates from fertilizers and detergents enter lake and ocean water Eutrophication is the unusual growth of algae and other microscopic organisms Oxygen using organisms eat the algae and deplete oxygen from lakes and the ocean, fish and other animals die Germs from sewage may pollute and cause disease Poisonous waste from factories causes a build up of poisons in fish Thermal energy is also a pollutant