Vital Resources- Water, the Atmosphere, and Nutrient Pollution
Over 70% of the earth’s surface is covered by water. What percentage of that water is fresh, and why is most freshwater unavailable for direct use by organisms?
Although the earth is covered by 70% water, there is limited water for consumption by human beings and other organisms. Of the 70% water coverage, only about 3% is safe for consumption (USGS, 2018). The rest of the water, which is primarily salty, constitutes what is referred to as the blue planet. The blue planet is water sources such as lakes, oceans, seas, among others. Therefore, there is no water shortage per se, only that what is available is not safe for consumption.
Surprisingly, the 3% of freshwater available is not fully accessible. About 2/3 of the 3% freshwater does not exist in liquid form (USGS, 2018). Instead, it is made up of ice sheets that occupy a significant part of Antarctica and Greenland. New technology has been adopted to melt such water to enable human beings to consume it, but it is not possible to undertake large-scale melting for global use. It is also worth noting that almost all freshwater exists underground beneath the earth’s surface. Estimates show that 25%-45% of drinking water is found in underground sources (USGS, 2018). The water later resurfaces on the earth’s surface through wells and wetlands. However, underground water sources do not replenish naturally, implying that it is a non-renewable resource. This puts further stress on freshwater availability for humans and other organisms.
Describe the zones of aquifers and how the water table changes over time.
According to USGS (2018), an aquifer refers to a collection of porous rocks filled with groundwater. These rocks sip water through saturation, and since they are porous, the water can quickly move through. Ostensibly, this water may end up on the earth’s surface in the form of wells and springs. These are arguably the largest sources of fresh drinking water on the earth’s surface since the water goes through a process that possibly cleans the water up.
Aquifers are further categorized into two: unconfined and confined aquifers. Unconfined aquifers are penetrable since they contain penetrable rock or soil above them (Scibek & Allen, 2006). On the other hand, confined aquifers contain a non-penetrable rock or clay above them; hence, water cannot go through them (Scibek & Allen, 2006). Most of these aquifers are made up of sediment rocks such as gravel, limestone, and sandstone. Thus, the classification of these aquifers depends on the type of rocks they are made of. It is worth noting that the aquifers are not underground rivers- a common misconception. The aquifers are organized so that water cannot flow as fast as it would be the case on an ordinary river on the earth’s surface. The flow rate depends on the nature and permeability of the constituent rocks.
The state of aquifers has a significant influence on the water table. Fluctuations in water level, therefore, are a result of changes in water flow through aquifers. The changes in the level are influenced by human and natural phenomena (Scibek & Allen, 2006). When people drill wells, for instance, they precipitate water flow to the earth’s surface. Furthermore, natural phenomena such as atmospheric pressure influence water flow. In a nutshell, any activity that affects the amount of water an aquifer can hold affects the water table.
Discuss freshwater wetlands. Name three types and describe their function in nature.
Freshwater wetlands are areas on the earth’s surface where stagnant/standing water covers. Unlike other water sources, freshwater wetlands are not connected to whole water sources such as rivers or oceans. These water sources are usually located on the boundaries of streams, ponds, lakes, among others. Also, freshwater wetlands can be normal holes that have been filled up with water through rain or underground water. Interestingly, these water points can serve as reliable freshwater sources as long as there is no external contamination. Freshwater wetlands may stay wet throughout the year or temporarily dry up, especially during the dry season. Excellent examples include the inland catchment areas in South Wales, characterized by shrubs, herbs, and sedges that are saturated with water. Freshwater wetlands include marshes, swamps, ponds, and begs (US EPA, 2015).
Marshes
Marshes are wetlands that are mostly inundated rather than submerged, depending on the year’s season. However, unlike the name, marshes can be made up of either salt water or fresh water. Marshes include diverse vegetation that has been able to adapt to the saturated soil associated with the marshes. Marches are further categorized into salty, coastal, fresh, and inland. The result is the formation of different ecosystems depending on the nature of the water and the location. The ecological significance of marshes is that they act as a home to wildlife, including shrimps, beavers, and newts (US EPA, 2015).
Swamps
There are two types of swamps; forested and shrubs. Unlike marshes, swamps are dominated by hard stem plants and not soft stem plants, as is the case with marshes. As a result, the flora can be used by human beings to get timber for construction purposes. Also, swamps have an ecological significance since they act as a home to fish and certain types of birds. Further, swamps are home to beavers, bobcats, snakes, among others. A good example is the Everglades swamp in Florida.
Bogs
Bogs are freshwater wetlands mostly covered by acidic waters and spongy coverings. Unlike marshes and swamps, bogs get their water through precipitation. As a result, bogs have an ecological significance in preventing flooding downstream.
Describe littoral, photic, benthic, and pelagic zones in the ocean
Littoral Zone
The littoral zone refers to the area near the shoreline of the ocean. It is located in between the region of low and high tides. Here water moves endlessly through currents, waves, and tides.
Photic Zone
The photic zone refers to the area that accesses sunlight in the ocean. Life in the ocean is limited to the photic zone since it is where photosynthesis can take place. The region extends a depth of about 200 meters from the surface.
Benthic Zone
The benthic zone refers to the bottom of the ocean. Notably, this zone supports life. The organisms that live there are called benthos. The benthic zone is further divided into other zones, depending on the depth from the pelagic zone.
Pelagic Zone
The pelagic zone refers to any part of the ocean other than shores and the coastline. It is the opposite of the demersal zone, which is any zone affected by the coastline and seafloor. Usually, the zone extends from somewhere between 200 meters-4000 meters in depth.
Discuss the four layers of the atmosphere.
The earth has a series of layers, each with its characteristics. The layers include the troposphere, stratosphere, mesosphere, thermosphere, and exosphere from ground level, respectively. However, the exosphere gradually fades off.
Troposphere
This is the lowest layer of the atmosphere. It is located 10km above sea level. Clouds mostly form in this layer because of the high concentration of water vapor.
Stratosphere
The stratosphere appears up to 50 kilometers above sea level. The infamous ozone layer is located here. The layer absorbs UV light and later converts it into heat- one of the reasons why temperatures are so high here.
Mesosphere
Located above the stratosphere, the mesosphere extends to about 85 kilometers above the surface of the earth. The temperature in the mesosphere is a bit low compared to the stratosphere. However, the air in this area is too thin to breathe.
Thermosphere
The thermosphere is located about 500-1000 km above sea level. This region is very hot since it absorbs UV light and X-rays, later breaking them down to heat. Temperatures in this region are quite high, ranging from 500-2000 degrees. There is very rare air in this region.
What are the effects of excessive nutrient pollution in surface waterways?
Pollution of nutrients in waterways poses a severe threat to aquatic and human life. For instance, nitrogen and phosphorous are natural components of air and water, but they pose serious threats if they are in excess (Manuel, 2014). Excess nitrogen and phosphorous pollution precipitate the growth of algae. Consequently, algae reduce oxygen levels in waterways. A reduction in oxygen levels threatens the life of fish. Also, the poisoning enhances toxin levels in the water, leading to diseases and even death in humans (Manuel, 2014). Such a form of poisoning affects both aquatic and human life.
Nutrient pollution of underground water also causes serious health threats to human life. Infants are also vulnerable to nitrates in drinking water, even at low levels (Manuel, 2014). Water is a very delicate commodity since one cannot tell whether the water is poisoned or not.
References
Manuel, J. (2014). Nutrient Pollution: A Persistent Threat to Waterways. Environmental Health Perspectives, 122(11). https://doi.org/10.1289/ehp.122-a304
Scibek, J., & Allen, D. M. (2006). Modeled impacts of predicted climate change on recharge and groundwater levels. Water Resources Research, 42(11). https://doi.org/10.1029/2005wr004742
US EPA, O. (2015, April 9). Classification and Types of Wetlands. Www.epa.gov. https://www.epa.gov/wetlands/classification-and-types-wetlands#undefined
USGS. (2018). Where is Earth’s Water? Usgs.gov. https://www.usgs.gov/special-topic/water-science-school/science/where-earths-water?qt-science_center_objects=0#qt-science_center_objects
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Question 
This week, we learned about one of our most vital resources: water. We also learned about the atmosphere and nutrient pollution. For your Unit 4 Complete assignment, write a narrative essay (minimum 1000 words) in which you address and discuss the questions and statements listed below. Use at least three scholarly sources, and remember to demonstrate a thorough understanding of the READ and ATTEND sections in your essay. Cite your sources in APA format.
Vital Resources- Water, the Atmosphere, and Nutrient Pollution
Over 70% of the earth’s surface is covered by water. What percentage of that water is fresh, and why is most freshwater unavailable for direct use by organisms?
Describe the zones of aquifers and how the water table changes over time.
Discuss freshwater wetlands. Name three types and describe their function in nature.
Describe littoral, photic, benthic, and pelagic zones in the ocean.
Discuss the four layers of the atmosphere.
What are the effects of excessive nutrient pollution in surface waterways?