Water Quality and The Water Cycle

WATER QUALITY AND THE WATER CYCLE ● Our Earth - The Blue Planet ○ Approximately 71% of the Earth is covered in water ■ The oceans hold about 96.5% of the Earth’s water ■ Water also exists in the air as water vapor, in rivers and lakes, icecaps and glaciers, in the ground, and even people. ● Most freshwater supplies are locked up in ice caps and glaciers we have a very limited amount of freshwater for drinking and growing crops ● The Water Cycle ○ Introduction to the Water Cycle ■ The water cycle describes the continuous movement of water on, above, and below the surface of the Earth; involves the processes of evaporation, condensation, precipitation, and runoff. ○ Key Processes ■ Evaporation: Water from oceans, lakes, rivers, and other water bodies is heated by the sun and changes from liquid to vapor, rising into the atmosphere. Energy from the sun drives this process. ■ Condensation: Water vapor in the atmosphere cools and condenses into tiny water droplets or ice crystals, forming clouds. Condensation occurs when air temperature decreases or when air becomes saturated with water vapor. ■ Precipitation: Water droplets in clouds combine to form larger droplets and fall to the Earth's surface as precipitation. Precipitation can take various forms including rain, snow, sleet, and hail. ■ Runoff: Precipitation that does not infiltrate into the ground or evaporate back into the atmosphere flows over the land surface, forming streams, rivers, and eventually returning to the oceans. Runoff carries sediments and nutrients, shaping the landscape and replenishing bodies of water. ○ Other Processes: ■ Infiltration: Some precipitation infiltrates into the ground, replenishing groundwater reserves and feeding into aquifers. Infiltrated water may eventually resurface through springs or be extracted through wells. ■ Transpiration: Plants absorb water through their roots and release it into the atmosphere through small openings in their leaves called stomata. This process, known as transpiration, contributes to the water cycle by returning water vapor to the atmosphere. ○ Factors Influencing the Water Cycle: ■ Temperature: Higher temperatures increase evaporation rates, while cooler temperatures promote condensation. ■ Humidity: Higher humidity levels slow down evaporation and increase the likelihood of precipitation. ■ Wind: Wind patterns influence the movement of water vapor and clouds, affecting precipitation patterns. ■ Topography: The shape and elevation of the land influence the distribution of precipitation and the flow of runoff. ● Water & Us ○ Your body is made up of roughly 60% water. ■ Your body needs water to carry out important functions such as temperature regulations, cell function, waste removal, and more. ■ This is why we need to make sure we have a generous supply of water available to us. ○ All living things need clean water to survive. Polluted water is one factor that can affect biodiversity in an area. ■ What are some ways water can become polluted? Dumping trash, chemicals, or other things into water. ■ How does water pollution impact ecosystems? Water pollution impacts ecosystems by killing off species or drastically influencing the quality of the water, also killing species. ■ How does water pollution impact human health? Pollution in our drinking water can severely impact our health. Contaminated water and poor sanitation are linked to the spread of diseases. ● Water Treatment Plants ○ Water can be filtered in many ways at waste management plants. There are multiple steps. ■ Coagulation: Chemicals are added to wastewater. This causes dirt and other dissolved particles in the water to clump together and form larger particles. ■ Flocculation: This is the mixing of the water to form flocs, which are larger, heavier particles. Often, additional chemicals are added to assist this process. ■ Sedimentation: Sedimentation separates solids from the water. This is possible because the flocs are heavier than the water, so they settle at the bottom. ■ Filtration: During filtration, clear water passes through multiple filters. This removes dissolved particles and germs, like dust, chemicals, parasites, bacteria, and viruses. ■ Disinfection: After filtration, chemicals like chlorine may be added to further disinfect the water. This helps to kill any remaining bacteria, parasites, and viruses. The Water Cycle. Image via Science Learning Hub. ■ Organisms, including plants, animals, and microbes, release carbon dioxide back into the atmosphere through respiration. ■ Respiration is the process by which organic compounds are broken down to release energy, with CO2 as a byproduct. ○ Decomposition: ■ Dead organisms and organic matter are broken down by decomposers, such as bacteria and fungi, releasing carbon dioxide back into the atmosphere or into the soil. ■ Decomposition is a vital part of the carbon cycle as it recycles carbon from dead organic matter. ○ Combustion: ■ Burning of fossil fuels, such as coal, oil, and natural gas, releases carbon dioxide into the atmosphere. ■ Combustion of biomass, such as forests, also contributes to carbon emissions. ● Factors Influencing the Carbon Cycle ○ Human Activities: Industrial processes, deforestation, agriculture, and the burning of fossil fuels significantly impact the carbon cycle, leading to increased carbon dioxide levels in the atmosphere. ○ Climate Change: Changes in temperature, precipitation factors, and other climate-related factors can influence the rates of photosynthesis, respiration, and other carbon cycle processes. ● Importance of the Carbon Cycle ○ Regulates the Earth’s temperature, makes up the food that sustains us, provides energy that fuels our economy ○ Produces nutrients and energy in plants for animal consumption ○ Responsible for all oxygen production