Chemistry of the Environment

Chemistry of the Environment. Chapter 12 Water Resources.

[Audio] Discussions on the Chemistry of Environment will be held, with the main focus on water resources. On the global scale, topics such as irrigation, virtual water, the problem of meat production, groundwater, water resources in the United States and the oceans will be explored. Let's now delve into the lecture's structure and take a more thorough look..

[Audio] Water resources make up 75% of the Earth's surface, mostly in the form of oceans covering 97%. The other three percent is made up of snowpack, glaciers, groundwater, streams, lakes, reservoirs, and a very small fraction of water in the atmosphere. It is important to have a good understanding of these resources to be able to use them correctly and get an insight into the Earth's workings..

[Audio] Oceans play an integral role in the Earth's water resources. Of all liquid water, 97% can be found in oceans, and 90% of the Earth's biomass is situated there as well. It is clear that oceans have an immense impact on our environment, helping it regulate its climate..

[Audio] Most of Earth's fresh water is stored as glacial ice, primarily in ice caps and glaciers, with only 2% of fresh water stored in this way. Glaciers are large, long-lasting rivers of ice that move slowly due to gravity, formed through the accumulation of snow which is then compacted and recrystallized to form the glacier. The preservation and responsible use of this fresh water stored in these ice caps and glaciers is essential..

[Audio] For our current slide, we are discussing the water resources of the environment. Specifically, we are looking at how the environment's water is stored through groundwater stores like Aquifers, infiltration, recharge zones, and percolation. It is important to note that only 0.6% of earth's fresh water exists as groundwater. This means that we must take care to protect this precious resource in order to keep our environment healthy..

[Audio] Water is a fundamental resource for all living things, and its proper care is of the utmost importance. Lakes, rivers, and ponds are essential to many aspects of our daily lives, providing us with access to drinking water, bathing, and other activities. The construction of large dams and reservoirs are often necessary to store water for later use, however, this can cause drastic changes to the flow of water and lead to the alteration of aquatic and riparian habitats. We must take care to understand the ramifications of our actions and use water in a sustainable and responsible manner..

[Audio] Plants play an important role in the water cycle through interception and transpiration. Interception occurs when precipitation is taken up by the leaves and branches of plants and the forest floor, causing a loss of precipitation for the local drainage basin. Transpiration is the exchange of gases in the stomata of plant leaves, which also leads to a loss of water for the local drainage basin..

[Audio] Water is an essential element of life on earth, making it worth exploring the water compartment in the atmosphere. The atmosphere contains a miniscule amount of water in comparison to the earth's total water supply, yet it is an integral reservoir. The atmosphere's water is replaced frequently, acting as a mechanism for dispersing fresh water across lands and restoring other reservoirs..

[Audio] In this section of our presentation, we will focus on the hydrological cycle and its effects on the global environment. The hydrological cycle is a major factor in the total solar energy absorbed by Earth’s surface and its movements form a loop. Annually, 111000 km3 of water falls to land, while 71000 km3 is released back into the atmosphere, with the rest – 40000 km3 – being runoff that reaches the oceans. Through this cycle, water is recycled as it evaporates from the ocean, forms clouds, precipitates and accumulates in lakes, rivers and seas..

[Audio] Water resources are an important part of the global perspective. Although humans withdraw a relatively small amount of water compared to total runoff, different continents vary in the amount of precipitation they receive. This water is used for a variety of purposes, from drinking and preparing meals to hygiene and irrigation. We will explore in greater detail how water is allocated among industries, and how it can be contaminated..

[Audio] Water is a limited resource and becoming increasingly scarce. Many people across the world suffer from chronic water shortages, and newly-growing populations put greater pressure on the water resources. Droughts create intense water shortages in areas with semiarid climates. This is referred to as water stress, meaning human and ecosystem needs are greater than what renewable supplies can provide. Conservation of water resources is essential to meet the needs of all people of the planet. This slide is part of Chapter 12, which focuses on the Chemistry of the Environment and Water Resources..

[Audio] Water is of great importance and its usage is only expected to increase in the future. Agriculture is responsible for two-thirds of total water withdrawal and 70% of water consumption worldwide, requiring substantial amounts of water for growing plants due to their high rate of transpiration. Thus, it is vital to efficiently manage and responsibly use the available water resources in order to meet the growing demand..

[Audio] We will be examining water resources in relation to the environment. Mainly focusing on transpiration's role in the water cycle and its effects on plants and agricultural practices. We will look into how water is absorbed by a plant's roots, and how the process of transpiration releases water vapor into the atmosphere. Additionally, we will discuss plant leaves being suited for efficient gas exchange and ways for plants to save water with closing their stomata and examine the following repercussions. Lastly, we will take into account how the amount of water transpired during growth varies between the different crop plants..

[Audio] Water resources are essential for our survival as a species, however, too much or too little water can present a huge issue. One of the most pressing dilemmas is the inefficiency of irrigation, leading to soil salinization. High evaporation leads to an increase of salt content in the soil, particularly in two-thirds of irrigated land in the lower basin of the Colorado River, which has lately endured water rationing. Consequently, efficient irrigation practices must be established..

[Audio] The problem of salinization in agriculture is an important issue. To tackle this, farmers are using flood irrigation, which unfortunately can contaminate streams and reduce the efficiency of irrigation. Sprinklers can also lead to high evaporation rates. However, new irrigation technologies can make improvements. Drip irrigation, a network of perforated plastic tubing that is placed on or below the surface, can achieve up to 95% efficiency and can also increase crop yields by avoiding soil saturation that can lead to leaching..

[Audio] Water is essential for all life on Earth, but human activities are making access to clean water increasingly scarce. "Virtual water" is the volume of water used to produce different products or services, and the virtual water content of meat products is much higher than plants. Diets rich in meat can lead to a large water use footprint, and when more of our food comes from irrigated land, this footprint grows larger. Considering our dietary choices can help reduce water scarcity..

[Audio] Discussions around the effects of over pumping of groundwater aquifers are an important consideration. Groundwater is a finite resource, and if not managed carefully it can have a number of serious consequences. Over pumping can limit food production, leading to higher food prices and increasing inequality between the rich and the poor. Additionally, it can cause land subsidence and draw saltwater into freshwater aquifers, making them unusable for irrigation or consumption. Considering these risks is essential when making decisions about our water resources..

[Audio] Groundwater is an essential resource, and it is important to be aware of the potential threats posed to it. Sources of groundwater pollution can be anything from mining activities, to runoff from urban areas, to hydraulic fracturing (often referred to as fracking). A notable example of groundwater pollution is methyl tertiary butyl ether (MTBE), a known carcinogen found in gasoline that has contaminated many aquifers. Groundwater is particularly vulnerable to pollution as it has lower concentrations of dissolved oxygen and fewer populations of decomposing bacteria. Polluted groundwater can take thousands of years to cleanse itself, so it is essential that we take measures to protect our groundwater resources..

[Audio] Groundwater is an integral component of our environment, yet it is very susceptible to contamination. Each day in the U S , approximately 4.5 trillion liters of polluted water enter the groundwater from sources like septic tanks, cesspools, landfills, and waste disposal sites. Just a single gallon of gas can render a million gallons of water unsuitable for drinking. In agricultural regions, fertilizers and pesticides can also pollute aquifers and wells, with these contaminants persisting for thousands of years. It is essential that we recognize the importance of groundwater and take action to safeguard it..

[Audio] Water resources in the US can be seen to be mostly located to the east of the country, with annual runoff ending up flowing to the Atlantic or the Gulf. 25% of the runoff is withdrawn for use, with the remaining 75% being returned to the stream flow. It is essential that efforts be put into protecting our water resources and finding sustainable ways to use and conserve them..

[Audio] Water is an essential resource for life yet its value is often underestimated. In the US, water is used for public supply, domestic use, commercial industry, irrigation, thermoelectric power, mining, livestock, and more. As the population grows, so does the demand for water resources. This chapter will look into the various kinds of water usage in the US and their implications..

[Audio] Today, we are discussing water resources in our environment and its chemistry. Specifically, we will focus on the oceans and their structures. The Earth is made up of four major oceans - the Pacific, Atlantic, Indian, and Arctic. In 2000, the International Hydrographic Organization officially added the Southern Ocean to form the fifth major ocean. The Pacific Ocean is the largest and deepest of the oceans, followed by the Atlantic, Indian, Arctic, and finally, the Southern Ocean. These oceans play an important role in our environment and in our lives..

[Audio] As we look at surface currents in Chapter 12, we can see that they develop in response to wind patterns caused by unequal heating of the Earth's surface. These currents generally follow the path of the global wind belts, and only around 2% of wind energy is transferred to the ocean's surface. We can also see that ocean currents are huge masses of water that move from one place to another. This movement is driven by the friction between the wind and the ocean's surface..

[Audio] We will delve into the chemistry of the environment, focusing on water resources. Beginning by examining the oceans and the factors that affect the flow of each one, we will explore how gravity, friction and the Coriolis effect play an essential role in oceanic movement. Knowing these dynamics assists us in comprehending how water and its chemistry shifts through the environment..

Major Surface Ocean Currents. [image] 03 07. Can you see a pattern?.

[Audio] Water Resources is a subject of the Chemistry of the Environment Chapter 12. The absorption of light increases the temperature and changes density, and this phenomenon can be seen in the ocean, where the water with the highest density is found at the bottom and the least dense at the surface. The permanent thermocline and pycnocline further separate the layers of water according to their densities, and play a vital role in keeping the phytoplankton levels near the surface so they can receive the necessary light..

[Audio] Oceans play an important role in regulating Earth's climate, particularly through thermohaline circulation, which enables the ocean to mix and move waters between the surface and the deep sea. Additionally, the cycles of the great ocean conveyor affects climate patterns. Let us delve deeper into the role that oceans play in regulating Earth's climate..

[Audio] The global conveyor belt is integral to the ocean's environment, with cold water being transported from the North Pole to the South Pole and warmer water travelling from the South Pole to the North Pole. At the North Pole, the cold water freezes to ice and leaves salt in its wake, which then downwells and mixes with the water column until it reaches the bottom. The water then moves southwards through the Atlantic Ocean, gradually warming as it moves closer to the equator, before it rises to the surface and creates a warm surface current on the west coast of North America. Finally, this current joins the Indian Ocean current and both currents travel north in the Atlantic back to the North Pole, thus completing the global conveyor belt..

[Audio] Global warming has a significant impact on water resources, particularly on the oceans. Rising sea surface temperatures impede the formation of deep water at the poles, impeding the exchange of nutrients between surface and deep that could disrupt marine ecosystems and potentially alter regional climates. This is especially pertinent for regions such as London, which has seen an uptick in temperatures in recent years..

[Audio] This chapter will focus on freshwater resources around the world and their use. We will explore the amount of water available in various regions, and the ways in which people use it for agriculture and other needs. Also, we will delve deeper into water consumption in the United States..

[Audio] For this week's homework, we will be examining the significance of water in the environment. Initially, we will be computing the proportions of corn mass to water intake, as well as its whereabouts. Following that, we will research the origins of drinking water in our neighborhood and the consequences of an amplified global temperature on the water cycle. Altogether, this is vital in understanding the all-encompassing chemistry of the environment..

[Audio] We'll begin by exploring hydrogen bonding and how different ions create strong and weak acids and bases when dissolved in water. We'll also examine how these acids and bases interact with each other and with other compounds. Through this, we will gain an understanding of the chemical properties of water and its role in environmental chemistry. By the end of this chapter, you will have a better comprehension of how water affects the environment..