Natalie Simpson's List: Gr. 9 Science Ecosystems Research Essay

• Acidification occurs when the capacity of the soil or water bodies to resist or neutralise acidifying atmospheric deposition begins to decline.

  Acidifying compounds may fall to the ground with rain or snow as wet deposition, or in the form of particles or gases as dry deposition. Ecosystems may eventually lose their neutralising or buffering capacity completely, if acid deposition rates persistently exceed their levels of tolerance.
• • - when water's natural ability to neutralize acid declines 
    - acid come in the form of precipitation or gas 
    - ecosystems may eventually lose the ability to neutralize the acid if the amount of acid persistently exceeds how quickly they can neutralize it
• Rainfall is naturally slightly acidic, but certain types of air pollutants can increase its acidity considerably. Combustion gases formed during the use of fossil fuels like oil, coal and peat particularly contain oxides of nitrogen and sulphur that can subsequently react in the atmosphere to produce acids that are dissolved in precipitation.
• • - rain is already a little acidic
    - that is why water has this neutralizing ability?
    - when we burn fossil fuels, oxides of nitrogen and sulphur are omitted 
    - these compounds react in the atmosphere to produce acids that are then dissolved into precipitation, and ultimately into the lakes 
• Acidification represents a serious threat to many plants and animals, particularly in sensitive aquatic ecosystems
• in acidic conditions toxic aluminium and heavy metal ions are more easily rinsed out of the soil and absorbed by living organisms.
• • - threat to plants and animals in aquatic ecosystems
    - in acidic conditions toxic aluminium and heavy metal ions are rinsed out of the soil and absorbed/consumed by plants and animals
    - most sensitive ecosystems are nutrient-poor lakes whose natural neutralizing (or buffering) capacity is already weak
• The ecosystems most sensitive to acidification are the nutrient-poor lakes and forests of northern Finland, whose natural buffering capacity is already weak.
• Acidification problems first became evident in the 1960s, when industrial emissions increased rapidly, and efficient methods for cleaning waste gases had not yet been developed
• • - these problems were first discovered in the 1960s
    - industrial emissions increased rapidly and cleaning methods had not been developed
    - "acid rain" kills fish and forests and decayed metal structures
    - international agreement forced industries to reduce/stop harmful emissions 
• the threat of  “acid rain” was clearly serious, with fish disappearing from some lakes, forests dying, and metal structures being rapidly corroded.
• international agreements were signed to force industries to curb harmful emissions, and these measures have been particularly successful where sulphur emissions are concerned.

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• • - Acidification of Mountain Lakes: Palaolimnology and Ecology project shows that the most severe acidification has taken place in Central and Western Europe

  • - evidence for the contamination of mountain lakes by these products can be demonstrated from the large concentration of non-marine sulphate and nitrate in the water
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  • • - combustion of coal and oil

    • - major reactive pollutants emitted during the combustion of fossil fuels include sulphur dioxide and nitric oxide
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• Acid rain describes any form of precipitation with high levels of nitric and sulfuric acids. It can also occur in the form of snow, fog, and tiny bits of dry material that settle to Earth
• most acid rain falls because of human activities
• biggest culprit is the burning of fossil fuels by coal-burning power plants, factories, and automobiles
• When humans burn fossil fuels, sulfur dioxide (SO2) and nitrogen oxides (NOx) are released into the atmosphere. These chemical gases react with water, oxygen, and other substances to form mild solutions of sulfuric and nitric acid
• Winds may spread these acidic solutions across the atmosphere and over hundreds of miles.
• it flows across the surface in runoff water, enters water systems, and sinks into the soil
• Acid rain makes waters acidic and causes them to absorb the aluminum that makes its way from soil into lakes and streams. This combination makes waters toxic to crayfish, clams, fish, and other aquatic animals.
• in an interconnected ecosystem, what impacts some species eventually impacts many more throughout the food chain—including non-aquatic species such as birds.
• The only way to fight acid rain is by curbing the release of the pollutants that cause it. This means burning fewer fossil fuels.
• But even if acid rain could be stopped today, it would still take many years for its harmful effects to disappear.
• Individuals can also help prevent acid rain by conserving energy. The less electricity people use in their homes, the fewer chemicals power plants will emit.
• Vehicles are also major fossil fuel users, so drivers can reduce emissions by using public transportation, carpooling, biking, or simply walking wherever possible.

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• A lake is a sizable water body surrounded by land and fed by rivers, springs, or local precipitation.

• Symptoms of poor ecosystem health include the following:

  • the loss of species;
  • the accelerated proliferation of organisms. One example is algae blooms caused by an excess of phosphorous and nitrogen compounds in the water. This condition is called "eutrophication";
  • increased incidences of tumours or deformities in animals;
  • a change in chemical properties. Perhaps one of the most significant has been a reduction of pH in water caused by acid rain;
  • the presence of certain organisms that indicate unsanitary conditions. Coliform bacteria, for example, are a sign that the system may contain organisms that cause a variety of human diseases such as diarrhea, typhoid, and cholera; and
  • the loss of traditional Aboriginal culture associated with the ecosystem.
• Many symptoms of poor ecosystem health occur simultaneously. For instance, increased lake acidity may kill certain species, thereby allowing the temporary proliferation of species more tolerant of acidity.
• Why is aquatic ecosystem health important to humans? Because everything is connected, where an ecosystem is out of balance eventually humans will begin to suffer as well.
• In many cases, mechanisms exist that allow us to help restore ecosystem health or minimize detrimental impacts caused by human use. Following are some of these mechanisms
• Environmental legislation
• Integrated resource planning
• Technology
• Environmental monitoring
• Compensatory measures
• Ecosystems are comprised of four basic components: water, land (rock and soils), air and living things (plants and animals including humans).

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• In 1976, scientists began acidifying a small ELA lake. In the first three years, enough sulfuric acid was gradually added to the lake to be comparable to 20 years exposure in an industrially impacted area.
• This proved aquatic ecosystems are damaged at much higher pH values than first believed
• sulfuric acid is a more potent acidifier of lakes, nitric acid is a significant source of lake acidification and nitrogen oxide emissions should be reduced

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• Most lakes and streams have a pH   between 6 and 8
• Lakes and   streams become acidic (pH value goes down) when the water itself and its   surrounding soil cannot buffer the acid rain enough to neutralize it.
• Many lakes and streams examined in a National Surface Water Survey (NSWS)  

  suffer from chronic acidity, a condition in which water has a constant   low pH level.
• The survey investigated the effects of acidic deposition   in over 1,000 lakes larger than 10 acres and in thousands of miles of   streams believed to be sensitive to acidification. Of the lakes and streams   surveyed, acid rain caused acidity in 75 percent of the acidic lakes and   about 50 percent of the acidic streams.
• Episodic   acidification refers to brief periods during which pH levels decrease   due to runoff from melting snow or heavy downpours.
• For example, approximately 70 percent   of sensitive lakes in the Adirondacks are at risk of episodic acidification.
• Episodic acidification   can cause "fish kills."
• As acid rain flows through soils   in a watershed, aluminum is released from soils into the lakes and streams   located in that watershed. So, as pH in a lake or stream decreases, aluminum   levels increase.
• Both low pH and increased aluminum levels are directly   toxic to fish. In addition, low pH and increased aluminum levels cause   chronic stress that may not kill individual fish, but leads to lower body   weight and smaller size and makes fish less able to compete for food and   habitat.
• as lakes and streams become more acidic, the   numbers and types of fish and other aquatic plants and animals that live   in these waters decrease.
• Scientists estimate   that from 10-45 percent of the nitrogen produced by various human activities   that reaches estuaries and coastal ecosystems is transported and deposited   via the atmosphere
• Nitrogen is an important   factor in causing eutrophication (oxygen depletion) of water bodies. The   symptoms of eutrophication include blooms of algae (both toxic and non-toxic),   declines in the health of fish and shellfish, loss of seagrass beds and   coral reefs, and ecological changes in food webs.
• These ecological changes impact   human populations by changing the availability of seafood and creating   a risk of consuming contaminated fish or shellfish, reducing our ability   to use and enjoy our coastal ecosystems, and causing economic impact on   people who rely on healthy coastal ecosystems, such as fishermen and those   who cater to tourists.
• If acidic deposition levels were to remain constant   over the next 50 years (the time frame used for projection models), the   acidification rate of lakes in the Adirondack Mountains that are larger   than 10 acres would rise by 50 percent or more.

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• A crystalline Adirondack lake once held up as an example of a “dead” lake devastated by acid rain has now become a symbol of nature’s ability to heal itself once pollutants are curbed.
• Brooktrout Lake teemed with trout before air pollution from faraway cities began to change the chemistry of lakes and soils
• In 1984, biologists found that Brooktrout Lake and hundreds of others in the rugged region were completely devoid of fish
• After the Clean Air Act amendments of 1990 tightened emissions limits on Midwest coal-burning power plants, acid rain decreased significantly. As expected, the pH levels of Adirondack lakes began to rise, becoming less acidic. The surprising thing was how fast it happened.
• “Nobody predicted Brooktrout Lake would come around as fast as it has,” said Clifford Siegfried, director of the New York State Museum and a freshwater ecologist who has studied Adirondack lakes since 1984. “Most predictions were for decades of recovery.”
• Last fall, biologists stocked Brooktrout Lake with 20 adult trout and 2,000 fingerling trout. It was the first time a once-dead Adirondack lake had been restocked with fish after improving enough to sustain fish.
• Charles Boylen, a biologist at Rensselaer Polytechnic Institute’s Darrin Fresh Water Institute
• “This is a great opportunity to see how nature deals with this phenomenon of acid recovery,” he said.
• Siegfried said. “These communities have adapted to having no fish for several decades. The top predator is the midge larva,” a wriggler the size of an eyelash. “These are nice juicy morsels for trout. They’ll likely wipe out that population.”
• Scientists also will be watching the behavior of a pair of loons that have been nesting on the lake for years. In the past, they’ve had to go to another lake to feed. Now they’ll find trout right at home. “We’ll see how that affects fish survival,” Siegfried said. “They can eat 1,500 fish annually.”
• The acid level is affected by precipitation and temperature, and the abundance of certain organisms rises and falls over short periods.
• “While there has been a substantial decrease in acid deposition, the improvement in lake chemistry has been relatively small,” Sullivan said. “If we continue to operate under existing emissions regulations, the lakes that have been recovering will stop recovering and will start to get worse again over the next couple of decades. For some lakes, it will be worse than it ever has been.”
• That’s because soils in the Adirondacks, particularly at higher elevations, have been depleted of calcium and other acid-neutralizing minerals, weakening their ability to serve as a buffer against acid rain, Sullivan said.
• To prevent reacidification of the region’s most sensitive lakes, such as Brooktrout, further emission controls are needed, he said.
• “Recovery is a dangerous word in the hands of politicians. They think the job is done,” Boylen said. “But even with more stringent regulations, there’s still more consumption of fossil fuels than in years past. If we don’t learn to conserve our energy consumption or rely on sources other than fossil fuels, the societal demands will continue to put more and more emissions into the atmosphere.”

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