Unit 8 Blog

Freshwater Resource Discussion

Underground aquifers, lakes, rivers and wetlands provide many ecological and economic benefits to their surrounding ecosystems.  Discuss both the ecological and economic benefits of each freshwater-ish source (I get that wetlands are not always freshwater... but they are super important!) giving at least two example for each.  Also give at least one example of how human activity can be harmful to each of these resources.

Underground Aquifers

Plant roots can access groundwater in an aquifer and grow in places they otherwise wouldn't be able to due to a lack of a nearby water source. The water in aquifers can also percolate to the surface as springs, which house freshwater aquatic biomes that enhance biodiversity and provide habitats for specific species. Aquifers can be used to provide water, viewed as a valuable commodity, to humans as drinking water. In addition to drinking water, underground aquifers can provide water for agricultural purposes as the Ogallala aquifer has been used in the Great Plains. If humans overdraw from the water table near coastlines, pressure is decreases and the adjacent salt water creeps into the area of rapid pumping in a process termed saltwater intrusion.

Lakes

Lakes can help moderate temperatures of nearby land since water has a high specific heat; this helps maintain a steady climate beneficial to organisms that live in the area that may be unused to increased temperature fluctuations. They also provide a habitat for many freshwater organisms, some specific to certain zones within lakes such as the littoral and benthic, which helps preserve biodiversity by providing another habitat in which to live. Lakes can be used as a reservoir for human drinking water, irrigation use, and other commercial activity. Additionally, they are often recreation hotspots and tourist destinations which can contribute to the local economy. Humans often deposit sewage and other anthropogenic chemicals in the lake which can upset ecosystems by leading to hypoxia via eutrophication or being directly harmful to organisms within the lake.

Rivers

Rivers provide breeding grounds for species like salmon that can't or won't breed elsewhere, making them key to biodiversity and sustainable populations of certain species. They also are home to freshwater ecosystems that are also key to biodiversity. Transportation across large landmasses and therefore trade would be much harder without rivers. Irrigation of farmlands and subsequently the agricultural sector is heavily reliant upon rivers, as well. Irrigation, however, diverts large amounts of water that can cause lower water levels or even complete drying up downstream. The use of fertilizers, herbicides, and insecticides in agriculture also runoff into the river and cause eutrophication or negatively affect organisms within the river.

Wetlands

Wetlands can filter pollutants from water and recharge groundwater with clean water which minimizes the negative effects pollutants can have on the local ecosystem. They can also absorb large amounts of rainwater and release it slowly elsewhere which helps minimize flooding; this is beneficial to maintaining biodiversity by allowing species to survive that wouldn't have been able to survive a strong flood. The mechanism against flooding is also helpful economical because it minimizes damage to local businesses and economies that would be harmed if floods made them close for a short time or entirely. Wetlands are also a huge tourist destination, especially in light of all the endangered species of birds that visit wetlands, which can be extremely beneficial to local economies. Many wetlands, however, have been drained of freshwater for agriculture, human settlement, or to eliminate breeding grounds for mosquitoes and other pathogens.

Water Diversion Discussion

Water is not always where we need it to be.  For thousands of years, humans have diverted water for their own needs via dams, dikes, and aqueducts.  Discuss 3 water diversion projects by first explaining the location of the source and then where the water ended up.  Next, for each example, discuss the ecological benefits and costs as well as the economic benefits and costs for each project (feel free to reference the work you did on your dam project if you would like or find some new examples that we haven't discussed!).

Three Gorges Dam

The Three Gorges Dam is located in the Hubei province in China, a relatively rural area. The dam spans the Yangtze River and creates a reservoir on one side of the dam, limiting water flow to the ocean. The actual construction of the dam required many roads which uprooted many ecosystems, in addition to the habitats replaced by the dam itself. The dam submerged many factories and other industrial waste sites which increased the level of pollution of water, harmful to all the organisms that come in contact with it as well as the soil. It also led to erosion in the reservoir and along the stream, leading to landslides that further decimated habitats. While it did provide an alternate source of electricity, the dam also displaced almost 1.2 million people and exacerbated drought conditions for those downstream. This extremely detrimental to human rights and the available labor force.


Salton Sea

The Salton Sea formed when canal gates on the Colorado River broke and the water pooled in the then Salton Trough on the San Andreas fault in California. The new lake did result in a new freshwater ecosystem in a place previously pretty bereft of organisms that is also the sole provider of water to other streams with their own unique ecosystems but the increased salinity of the lake also caused many species to die off eventually and the increased salinity is spread to its streams, as well.
Tourism is a large part of the local economy around the Salton Sea and the water is also used for irrigation. The increased use of the water for irrigation has the put the lake in danger, however, and could be lethal to the tourism industry as well.



Aral Sea

The Aral Sea is located across Kazakhstan and Uzbekistan; its waters were diverted for Soviet irrigation projects that resulted in much of the lake drying up and separating it into a North and South Aral Sea. While the irrigation made the surrounding land more fertile and increased the number of organisms in the area as well as farmers, the lake ecosystems were severely harmed since much of the lake could no longer exist. As the lake dries, all the toxic chemicals that were in it dry as well and are spread around as dust which is harmful to all organisms in the area. The fishing industry that was once prosperous in the area died off as the fish did with the lake resulting in mass unemployment. There are also many health issues associated with the lake which is detrimental to humans and therefore labor force.

Water Quality Discussion

When we were at Parr park, we did several water quality tests to assess the health of the ecosystem.  Discuss each test and what the test indicates about the quality of the water we tested including potential sources of the pollutant associated with the test.  In addition to tests humans can run on the water itself, there are many species that can be studied that give an indication of the health of an ecosystem.  These species are known as indicator species.  Give an example of a biological indicator species and explain how changes in its morphology or population numbers gave scientists an indication that something just wasn't right in the area.  Make sure to discuss what scientists believe to be the cause of this species change.   

The pH of the water was 7 which is consistent with what it should be, indicating that there was no undue acidic or basic substances introduced. There wasn't any nitrate, indicating there was little to no runoff of fertilizers or that all the nitrate had been consumed by primary producer activity. Phosphate levels were also low but there was still some phosphate so it can be inferred that nitrogen is probably the limiting factor in the environment. The temperature was about 10 degrees Celsius which is fairly expected for the weather we had that day. There was a moderate amount of dissolved oxygen which is to be expected due to the colder temperature of the water. Colder water is able to hold more oxygen. Samples were taken to test BOD, fecal coliform levels, and solids in the water but we have as yet been unable to conduct the tests in the lab due to snow days. 

Lichens, a combination of an alga and fungus, make great indicator species for air pollution. In Britain, bushy lichens only grow if the air is clean, leafy lichens grow in moderate levels of pollution and crusty lichens can tolerate high levels of pollutants. If no pollutants are present, then air pollution is very great. Lichens also grow larger in cleaner air. Scientists believe the cause in species change occurs because lichen trap dust and organic matter from the air around them, making them extremely sensitive to particles in the air. Acidic particles from fossil fuel burning such as sulfur dioxide therefore harm their growth.

Water Conservation Discussion

Only 3% of the world's water is freshwater, of that 3%, less and 1% is available for human use.  The 3 largest consumers of freshwater are agriculture, industry and household use, in that order.  Give at least two suggestions for how each consumer listed above could make changes to better conserve this valuable resource.     

Agricultural consumers could use drip systems for irrigation which have the most efficient level of water distribution of all current known methods of irrigation. They could also switch to hardier GMOs that require less water and produce more crop. Industry could also switch to more efficient methods of water use. In industries that use water as a cooling mechanism, they could use a closed system and reuse the water to cool instead of releasing large amounts of it into the atmosphere. Additionally, they can use machinery that is more water efficient and collect rainwater to use for their purposes. Households can install dual flush toilets that minimize the amount of water needed to flush and also reuse grey water for suitable purposes instead of using clean drinking water.

BIG Picture Discussion

This is where you will make the four BIG PICTURE connections to the ENTIRE UNIT. Please tie in information you learned in your reading (chapters 9 and 14), from completing your assignments, the documentaries we watched and from your labs.  There is not an exact length that I am expecting other than it should definitely be at least a paragraph for each section, should be thorough and show understanding of the topic.  Remember to be specific in your examples.  Do not just say "there are laws that govern this" or "people destroy the Earth."  Give me the names of the laws, what they regulate and who enforces them.  Tell me what humans are doing to destroy the earth.     

Human Impact

Humans are vastly affected by waterways since water is so necessary to human existence. Historically, they have only been able to settle near rivers or other sources of freshwater because there was no other way to access that necessity. Today, that is still true in many developing countries but in pipes and transportation systems have made it possible for people to settle in places they otherwise couldn't have. We can now access groundwater in aquifers for human use. Human use of water also affects the bodies of water in turn. Overuse of aquifers and wells have resulted in groundwater depletion and cones of depression. The use of different anthropogenic chemicals has also polluted water, which can cause eutrophication and otherwise upset the aquatic ecosystem. Dams, levees, and dikes divert water and can cause bodies of water to dry out or increase in salinity which is detrimental to the organisms in the water.


Environmental Impact

Runoff of fertilizers can cause eutrophication which results in hypoxia that makes it impossible for many of the organisms in the water to survive. Herbicides and pesticides also runoff and can be consumed by the organisms in the water as well. Even if the organisms who initially consume the chemical are unaffected (though they usually also experience detrimental effects), bioaccumulation causes negative effects in organisms at higher trophic levels. The drying up of lakes and groundwater due to human overuse eradicates habitats and makes it impossible for some plants to get enough water which is harmful to biodiversity and therefore harmful the the sustainability of the ecosystem. Increased salinity of the water caused by evaporation and human overuse also kill off organisms who are now out of their niche. They can also be taken out of their niche by temperature change that occurs by the heat pollution of industries dumping hot water into bodies of water that are normally cooler.


Economic Impact

Water is incredibly important to the economy. It's necessary to humans which make up the labor force as humans must drink water but water is also key to food since food sources wouldn't survive without water. Agriculture, a large sector of the economy, is reliant upon water, especially when considering irrigation. More mechanized industry also uses water. Electricity generation, key to the functioning of modern society, uses water to turn into steam to turn the turbines. Multiple other industries also use water as a cooling mechanism. Bottled water has also become a huge industry as water has become its own commodity.


Legislation

The Clean Water Act of 1972 protects wildlife and the conditions of surface waters. It gave the Environmental Protection Agency (EPA) the authority to take actions to maintain and regulate surface waters. The Safe Drinking Water Act, last updated in 1996, allows the EPA to establish maximum contaminant levels of different substances in drinking water that municipal systems must meet. This legislation has only arisen as countries have become more developed and people have been in a position to look out for the environment. In developing countries, there are still not many regulations which attracts industry but is also extremely detrimental to their ecosystems.