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 * 1) This paper is a mess- read through and fact check because at least one of the authors has plagiarized

Freshwater vs ocean acidification section editing-

The ocean and the atmosphere are constantly exchanging massive amounts of CO2. Over the last 800 000 years, the concentration of CO2 in the atmosphere remained around 172-300 parts per million by volume (ppmv). With recent anthropogenic CO2 emissions, this number has increased to 387 ppmv in 2009. From 2000-2008, 26% of anthropogenic CO2 was absorbed by the ocean. Although ocean acidification is also caused by other chemical additions and removals, CO2 is the primary factor affecting pH. Once CO2 is dissolved in seawater, it becomes a weak acid that primarily affects carbonate chemistry. Dissolved CO2 increases the concentration of bicarbonate ions (HCO3−), dissolved inorganic carbon (CT) and lowers the pH. Freshwater also absorbs atmospheric CO2, which can also lower the pH, however, freshwater alkalinity is much lower than seawater, due to the absence of a salt-buffer. In addition to CO2, freshwater reservoirs' pH values are altered by acid rain, nutrient runoff, and other anthropogenic pollutants. Therefore, the freshwater biota tends to have a higher evolutionary pH tolerance than seawater biota.

*** This sentence makes no sense- read the source and rephrase "Due to the lack of salt-buffer, pH changes in freshwater tend to be much greater than ocean water, due to newly released H+ ions not being buffered by as many bicarbonate (HCO3−) ions as ocean water. "

CO2
CO2 from the atmosphere can dissolve on the surface of freshwater to form carbonic acid. The total inorganic carbon in freshwater involves free CO2 (or H2CO3), bicarbonate (HCO3−), and carbonate (CO32-). The percentage of all these constituents is also dependent on the pH of the body of water. [WHAT IS THE PURPOSE OF THIS INFORMATION?] When water is acidic it will primarily contain CO2. It is often difficult to quantify the effects of pCO2 levels (partial pressure) in freshwater due to the various sources of carbon dioxide freshwater ecosystems receive. Factors such as nearby ecosystem, agriculture, land use, watershed, lake size, precipitation, soil type, and rocks all determine the amount of CO2 absorbed. However, there has been a clear increase in pCO2 in freshwater ecosystems in the last century due to anthropogenic influence. As the vegetation near freshwater ecosystems grow larger and multiply, due to the excess pCO2 feeding these plants, the carbon available at death and during decomposition increases. Then, precipitation, weathering, and runoff will wash this soil into the nearby water. When the pCO2 from the decomposing vegetation reacts with the water, it forms carbonic acid, which contributes to a lower pH level.

**** THE SENTENCE THAT IS STRIKEDTHROUGH IS PLAGIARIZED "The total inorganic carbon in freshwater systems is comprised of free CO2 (or H2CO3), HCO3− and carbonate (CO32−), and the percentage of each of these compounds is dependent on the pH of the water body; basic water contains a larger proportion of CO32−, while acidic water primarily contains free CO2 (Wetzel 2001)" - direct quote from


 * 1) REWRITING

CO2
There has been a clear increase of pCO2 in freshwater ecosystems in the last century due to anthropogenic influence that is contributing to freshwater acidification. It is often difficult to quantify the effects of pCO2 levels (partial pressure) in freshwater due to the various sources of carbon dioxide and the many factors that affect it such as the surrounding landscape, climate, the organisms present, the water's chemistry, and biological processes (e.g., photosynthesis, respiration). The dominant species of inorganic carbon present in freshwater can be a pH indicator with more CO32- being present in basic water and free CO2 in acidic water because when CO2 dissolves into the surface of freshwater it reacts to form carbonic acid. Along with the overall trend of increasing CO2 in the atmosphere that is being absorbed by bodies of water, the levels of carbon dioxide fluctuate daily and seasonally.

SOx and NOx
Two of the main contributors to freshwater acidification are sulfur oxides and nitric oxides. The accelerated burning of fossil fuels over the past two centuries has largely contributed to the acidification of freshwater ecosystems. International cooperation and environmental legislation have reduced SOx and NOx in recent decades as sulfate emissions peaked in the 1970s with nitrogen following behind 10 years later. Increased sulfate concentration in runoff due to increased acidity inputs is coupled with both an increase in base cation run-off and a decrease of bicarbonate, creating the acidifying effects in aquatic systems. Acidic rain seeps into and reacts with clay particles in the soil which leads to the leaching of aluminum into nearby bodies of water. Thus as the pH levels decrease, aluminum levels will increase. The higher levels of aluminum can also contaminate drinking water for humans which can lead to several health diseases. This creates a toxic environment to marine species and their environment which can lead to the extinction of species, reductions in population size, and overall a decrease in biodiversity. Most nitrogen in its natural state that is put into terrestrial ecosystems will be utilized by vegetation. However, in large amounts, not all of the nitrogen is able to be taken up by vegetation so the excess gets washed away with runoff in the form of nitrate. Nitrate will contribute to acidification in the same manner as sulfate.

Reducing Acidification
There are processes we can to do try and remediate the acidification of freshwaters. Liming is one such practice where calcium carbonate (CaCO3) is added to these systems. When added to rivers, in some, there were positive effects on the wildlife, increasing the abundance of fish and acid-sensitive invertebrates. However, these effects are variable and other studies had results that showed a decrease in invertebrate abundance. A large decrease of acid rain and acidic bodies of water in the past couple of decades has been a result of governmental regulations on anthropogenic emissions, specifically SOx and NOx.