Here is a detailed image of the full carbon cycle upright=1.5|NOAA provides evidence for the upwelling of "acidified" water onto the Continental Shelf. In the figure above, note the vertical sections of (A) temperature, (B) aragonite saturation, (C) pH, (D) DIC, and (E) p on transect line 5 off Pt. St. George, California. The potential density surfaces are superimposed on the temperature section. The 26.2 potential density surface delineates the location of the first instance in which the undersaturated water is upwelled from depths of 150 to 200 m onto the shelf and outcropping at the surface near the coast. The red dots represent sample locations. upright=1.3|Ocean Acidification Infographic Ocean acidification is the ongoing decrease in the pH value of the Earth's oceans, caused by the uptake of carbon dioxide () from the atmosphere. The main cause of ocean acidification is the burning of fossil fuels. Seawater is slightly basic (meaning pH > 7), and ocean acidification involves a shift towards pH-neutral conditions rather than a transition to acidic conditions (pH < 7).The ocean would not become acidic even if it were to absorb the CO2 produced from the combustion of all fossil fuel resources. The concern with ocean acidification is that it can lead to the decreased production of the shells of shellfish and other aquatic life with calcium carbonate shells, as well as some other physiological challenges for marine organisms. The calcium carbonate shelled organisms can not reproduce under high saturated acidotic waters. An estimated 30–40\% of the carbon dioxide from human activity released into the atmosphere dissolves into oceans, rivers and lakes. Some of it reacts with the water to form carbonic acid. Some of the resulting carbonic acid molecules dissociate into a bicarbonate ion and a hydrogen ion, thus increasing ocean acidity (H+ ion concentration). Although the largest changes are expected in the future, a report from NOAA scientists found large quantities of water undersaturated in aragonite  are already upwelling close to the Pacific continental shelf area of North America.  Continental shelves play an important role in marine ecosystems since most marine organisms live or are spawned there, and though the study only dealt with the area from Vancouver to Northern California, the authors suggest that other shelf areas may be experiencing similar effects. Current rates of ocean acidification have been compared with the greenhouse event at the Paleocene–Eocene boundary (about 55 million years ago) when surface ocean temperatures rose by 5–6 degrees Celsius. No catastrophe was seen in surface ecosystems, yet bottom-dwelling organisms in the deep ocean experienced a major extinction. The current acidification is on a path to reach levels higher than any seen in the last 65 million years, and the rate of increase is about ten times the rate that preceded the Paleocene–Eocene mass extinction. The current and projected acidification has been described as an almost unprecedented geological event. A National Research Council study released in April 2010 likewise concluded that "the level of acid in the oceans is increasing at an unprecedented rate".United States National Research Council, 2010. Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean A 2012 paper in the journal Science examined the geological record in an attempt to find a historical analog for current global conditions as well as those of the future. The researchers determined that the current rate of ocean acidification is faster than at any time in the past 300 million years. JournalistsResource.org, retrieved 14 March 2012 The rate at which ocean acidification will occur may be influenced by the rate of surface ocean warming, because the chemical equilibria that govern seawater pH are temperature-dependent. Greater seawater warming could lead to a smaller change in pH for a given increase in CO2.  Reducing emissions Members of the InterAcademy Panel recommended that by 2050, global anthropogenic emissions be reduced less than 50\% of the 1990 level. The 2009 statement also called on world leaders to:  Acknowledge that ocean acidification is a direct and real consequence of increasing atmospheric concentrations, is already having an effect at current concentrations, and is likely to cause grave harm to important marine ecosystems as concentrations reach 450 [parts-per-million (ppm)] and above; ... Recognize that reducing the build up of in the atmosphere is the only practicable solution to mitigating ocean acidification; ... Reinvigorate action to reduce stressors, such as overfishing and pollution, on marine ecosystems to increase resilience to ocean acidification. Stabilizing atmospheric concentrations at 450 ppm would require near-term emissions reductions, with steeper reductions over time.
Here is a detailed image of the full carbon cycleOcean acidification is the ongoing decrease in the pH value of the Earth's oceans, caused by the uptake of carbon dioxide () from the atmosphere. The main cause of ocean acidification is the burning of fossil fuels. Seawater is slightly basic (meaning pH > 7), and ocean acidification involves a shift towards pH-neutral conditions rather than a transition to acidic conditions (pH < 7).The ocean would not become acidic even if it were to absorb the CO2 produced from the combustion of all fossil fuel resources. The concern with ocean acidification is that it can lead to the decreased production of the shells of shellfish and other aquatic life with calcium carbonate shells, as well as some other physiological challenges for marine organisms. The calcium carbonate shelled organisms can not reproduce under high saturated acidotic waters. An estimated 30–40\% of the carbon dioxide from human activity released into the atmosphere dissolves into oceans, rivers and lakes. Some of it reacts with the water to form carbonic acid. Some of the resulting carbonic acid molecules dissociate into a bicarbonate ion and a hydrogen ion, thus increasing ocean acidity (H+ ion concentration). Although the largest changes are expected in the future, many factors are currently causing pH to change in addition to atmospheric . Biological processes, such as photosynthesis and respiration, are a main driver of this change in coastal areas; changes to ecosystem metabolism led to pH and oxygen declines. A report from NOAA scientists found large quantities of water undersaturated in aragonite , owing to the release of from the breakdown of sinking organic matter, are already upwelling close to the Pacific continental shelf area of North America. Water upwelled onto the coast is then modified by biological activity. Continental shelves play an important role in marine ecosystems since most marine organisms live or are spawned there, and though the study only dealt with the area from Vancouver to Northern California, the authors suggest that other shelf areas may be experiencing similar effects. Current rates of ocean acidification have been compared with the greenhouse event at the Paleocene–Eocene boundary (about 55 million years ago) when surface ocean temperatures rose by 5–6 degrees Celsius. No catastrophe was seen in surface ecosystems, yet bottom-dwelling organisms in the deep ocean experienced a major extinction. The current acidification is on a path to reach levels higher than any seen in the last 65 million years, and the rate of increase is about ten times the rate that preceded the Paleocene–Eocene mass extinction. The current and projected acidification has been described as an almost unprecedented geological event. A National Research Council study released in April 2010 likewise concluded that "the level of acid in the oceans is increasing at an unprecedented rate".United States National Research Council, 2010. Ocean Acidification: A National Strategy to Meet the Challenges of a Changing Ocean A 2012 paper in the journal Science examined the geological record in an attempt to find a historical analog for current global conditions as well as those of the future. The researchers determined that the current rate of ocean acidification is faster than at any time in the past 300 million years. JournalistsResource.org, retrieved 14 March 2012upright=1.3|Ocean Acidification Infographic The rate at which ocean acidification will occur may be influenced by the rate of surface ocean warming, because the chemical equilibria that govern seawater pH are temperature-dependent. Greater seawater warming could lead to a smaller change in pH for a given increase in CO2. In coastal regions, ecosystem metabolism can lead to large pH changes; the rate of biologically-induced pH change is also dependent on water temperature as rates of photosynthesis and respiration are temperature dependent. Reducing emissions Members of the InterAcademy Panel recommended that by 2050, global anthropogenic emissions be reduced less than 50\% of the 1990 level. The 2009 statement also called on world leaders to: upright=1.5|NOAA provides evidence for the upwelling of "acidified" water onto the Continental Shelf. In the figure above, note the vertical sections of (A) temperature, (B) aragonite saturation, (C) pH, (D) DIC, and (E) p on transect line 5 off Pt. St. George, California. The potential density surfaces are superimposed on the temperature section. The 26.2 potential density surface delineates the location of the first instance in which the undersaturated water is upwelled from depths of 150 to 200 m onto the shelf and outcropping at the surface near the coast. The red dots represent sample locations. Acknowledge that ocean acidification is a direct and real consequence of increasing atmospheric concentrations, is already having an effect at current concentrations, and is likely to cause grave harm to important marine ecosystems as concentrations reach 450 [parts-per-million (ppm)] and above; ... Recognize that reducing the build up of in the atmosphere is the only practicable solution to mitigating ocean acidification; ... Reinvigorate action to reduce stressors, such as overfishing and pollution, on marine ecosystems to increase resilience to ocean acidification. Stabilizing atmospheric concentrations at 450 ppm would require near-term emissions reductions, with steeper reductions over time.
D
cycle upright=1.5|NOAA provides evidence for the upwelling of "acidified" water onto the Continental Shelf. In the figure above, note the vertical sections of (A) temperature, (B) aragonite saturation, (C) pH, (D) DIC, and (E) p on transect line 5 off Pt. St. George, California. The potential density surfaces are superimposed on the temperature section. The 26.2 potential density surface delineates the location of the first instance in which the undersaturated water is upwelled from depths of 150 to 200 m onto the shelf and outcropping at the surface near the coast. The red dots represent sample locations. upright=1.3|Ocean Acidification Infographic
R
Ocean
cycleOcean
R
a
many factors are currently causing pH to change in addition to atmospheric . Biological processes, such as photosynthesis and respiration, are a main driver of this change in coastal areas; changes to ecosystem metabolism led to pH and oxygen declines. A
A
, owing to the release of from the breakdown of sinking organic matter,
A
Water upwelled onto the coast is then modified by biological activity.
R
2012
2012upright=1.3|Ocean Acidification Infographic
A
In coastal regions, ecosystem metabolism can lead to large pH changes; the rate of biologically-induced pH change is also dependent on water temperature as rates of photosynthesis and respiration are temperature dependent.
A
upright=1.5|NOAA provides evidence for the upwelling of "acidified" water onto the Continental Shelf. In the figure above, note the vertical sections of (A) temperature, (B) aragonite saturation, (C) pH, (D) DIC, and (E) p on transect line 5 off Pt. St. George, California. The potential density surfaces are superimposed on the temperature section. The 26.2 potential density surface delineates the location of the first instance in which the undersaturated water is upwelled from depths of 150 to 200 m onto the shelf and outcropping at the surface near the coast. The red dots represent sample locations.