Ocean Acidification

By: Melissa Santiago

Ocean Acidification

  The issue of ocean acidification is simple chemistry. There are two important things to when carbon dioxide dissolves in seawater. First, the pH of seawater water gets lower as it becomes more acidic. Second, this process binds up carbonate ions and makes them less abundant ions that corals, oysters, mussels, and many other shelled organisms need to build shells and skeletons. When water (H2O) and CO2 mix, they combine to form carbonic acid (H2CO3). Carbonic acid is weak compared to some of the well-known acids that break down solids, such as hydrochloric acid (the main ingredient in gastric acid, which digests food in your stomach) and sulfuric acid (the main ingredient in car batteries, which can burn your skin with just a drop). The weaker carbonic acid may not act as quickly, but it works the same way as all acids: it releases hydrogen ions (H+), which bond with other molecules in the area. The lower the pH, the more acidic the solution. It’s hard to say what the level of impact would mean for different organisms; a 10% rate could be no problem for some species, but for other more sensitive species it could mean one step closer to local extinction, ( Azevedo, De Schryver, Hendriks, Huijbregts, 2015).

   Like calcium ions, hydrogen ions tend to bond with carbonate but they have a greater attraction to carbonate than calcium. When a hydrogen bond with carbonate, a bicarbonate ion (HCO3-) is formed. Shell-building organisms can’t extract the carbonate ion they need from bicarbonate, preventing them from using that carbonate to grow a new shell. In this way, the hydrogen essentially binds up the carbonate ions, making it harder for shelled animals to build their homes. Even if animals are able to build skeletons in more acidic water, they may have to spend more energy to do so, taking away resources from other activities like reproduction. If there are too many hydrogen ions around and not enough molecules for them to bond with, they can even begin breaking existing calcium carbonate molecules apart, dissolving shells that already exist.

   “The ocean has to be one of the things greatly affected by global warming and climate change since it has to take up about 50% of anthropogenic CO2”(Wikipedia, 2018). This affects the level of oxygen thus the life of organisms in the ecosystem contaminated. The increase in the level of CO2 is a factor that contributes to the acidity of the ocean. The rise in acidity affects the production of organisms shrimps and corals by a process called calcifications. Corals reefs provide an ecosystem for one-quarter of marine life. The death of coral reefs leads to fish migration. Fish migration is the moving from one part of a water body to another. There are many factors which contribute to fish migration but the rise in the temperature of the sea water

due to global warming has now become one. This migration would then affect fishermen and everyone who benefits from marine life directly or indirectly.

  Azevedo (2015) explain, “Calcifying species are indispensable for ecosystems worldwide: they provide nursery habitats for fish, food for marine predators, and natural defenses for storms and erosion. These species are also particularly vulnerable to ocean acidification triggered by increased fossil fuel emissions”.

  Fossil fuel emissions are the gases that are spewed out of most cars, airplanes, power plants, and factories that are burning fossil fuels (coal, oil or gas).  Since the industrial revolution, fossil fuel consumption has risen exponentially to create many climates change-related issues, including ocean acidification. Deforestation is a two-fold issue.  Burning down forests is similar to burning fossil fuels, it emits a lot of carbon dioxide into the atmosphere. Forests are important because large expanses of plant life (even in the ocean) are known to be ‘carbon sinks’,  taking in carbon dioxide for photosynthesis. Historically, carbon dioxide levels have been balanced; the CO2 being produced was, in turn, being absorbed. Deforestation not only creates more CO2, but it also destroys one of the very things that helps absorb it.

For the coming week I plan on doing research on how human actives are affecting our Home.


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