Ocean Acidification

Ocean acidification is the gradual acidification of ocean waters as they absorb and release excess carbon dioxide (CO2) from the atmosphere. Since the industrial revolution, the pH of seawater has decreased by 0.1. The increasing acidity of seawater will change the balance of seawater chemistry and pose a great threat to a variety of Marine organisms and ecosystems that depend on the stability of the chemical environment.

CATALOGUE

1Noun explanation

2The history

3Cause of occurrence

4Hazards of acidification

   4.1 Phytoplankton

   4.2 Mollusks

   4.3 Effects on fish

   4.4 Heavy rains

   4.5 Human livelihood

   4.6 Coral may disappear

5Measures to prevent

6Declaration of Monaco

1Noun explanation

Ocean acidification is the phenomenon in which seawater absorbs excess carbon dioxide from the air, resulting in a decrease in acidity and alkalinity. PH value is generally expressed in terms of pH value, ranging from 0 to 14. PH value of 0 means the most acidic, while pH value of 14 means the most basic. Distilled water has a pH of 7, which is neutral. Seawater should be slightly alkaline, with a surface water pH of about 8.2. When excess carbon dioxide from the air enters the oceans, they become acidic. Scientists have shown that by 2012, due to human activity, excess carbon dioxide emissions had reduced the surface pH of seawater by 0.1, meaning it had become 30% more acidic. Surface acidity is expected to fall to 7.8 per cent by 2100, when it will be 150 per cent higher than in 1800.

2The history

In 1956, American geochemist Logan Lowell set out to study the climate effects of carbon dioxide produced during the great industrial period over the next 50 years. Logan and his partners set up two monitoring stations in remote areas far from the carbon dioxide emissions. One is in the South Pole, where there is little industrial activity and little vegetation, far from the crowd. The other is on top of mauna loa in Hawaii. For 50 years, their work has been almost uninterrupted.

Logan's monitoring found that carbon dioxide levels were higher each year than in the previous year, and that the change in carbon dioxide levels coincided with the changing of the growing season in the northern hemisphere. This observation quickly convinced the scientific community that Logan was right to worry that not all of the carbon dioxide released into the atmosphere would be absorbed by plants and the oceans, leaving much of it in the atmosphere. Logan also calculated that the amount of carbon dioxide absorbed by the ocean is enormous.

In 2012, scientists in the United States and Europe published a new study showing that the oceans are acidifying at their fastest rate in 300 million years, faster than they did 55 million years ago when life became extinct.

3Cause of occurrence

The oceans and atmosphere are constantly exchanging gases, and any component released into the atmosphere will eventually dissolve in the ocean. Before the advent of the industrial age, changes in carbon in the atmosphere were largely caused by natural factors, which caused natural fluctuations in the global climate. Since the beginning of the industrial revolution, mankind has extracted and used fossil fuels such as coal, oil and natural gas, and cut down a lot of forests. By the early 21st century, more than 500 billion tons of carbon dioxide had been discharged. This has caused carbon levels in the atmosphere to rise year by year. The component of the atmosphere that is affected by the wind first melts into the surface of the ocean hundreds of feet deep, and over the next few centuries it gradually spreads to every corner of the ocean floor. Studies show that in the 19th and 20th centuries, the oceans absorbed 30 percent of humanity's carbon dioxide emissions and are still absorbing them at a rate of about a million tons per hour. The acidification of the sea is caused by human activities.

4Hazards of acidification

Since the industrial revolution, more than one-third of the CO2 released by human activities has been absorbed by the ocean, increasing the concentration of hydrogen ions in surface waters by 30% and decreasing the pH value by 0.1 in the past 200 years. As the main force of photosynthesis in the ocean, phytoplankton have many phyla and diverse physiological structures, and have different utilization capacities for different forms of carbon in seawater. Therefore, ocean acidification will change the conditions for species competition.

In 2003, the term "ocean acidification" first appeared in the prestigious British scientific journal nature. By 2005, disaster and emergency expert James nesseus had further outlined the potential threat of "ocean acidification." His research found that the oceans took at least 100,000 years to recover from an extinction event 55 million years ago, caused by an estimated 450 billion tonnes of carbon dioxide dissolved in the water.

In March 2012, the army of the United States, Britain, Spain, Germany and the Netherlands international team of scientists of 21 researchers published in the latest issue of the journal science reports that affected by human emissions of greenhouse gases, the earth is going through in the past 300 million years the fastest ocean acidification process, more than four times in the history of life on earth mass extinction, many sea creatures so threatened for survival.

phytoplankton

Since phytoplankton form the basis and primary productivity of the ocean's food web, their "reshuffling" is likely to lead to everything from small fish and shrimp to sharks,

Many of the whales' Marine animals are under attack. In addition, in seawater with a lower pH value, the nutrient feed value will decrease, and the phytoplankton's ability to absorb various nutrients will also change. What's more, the increasingly acidic seawater is also corroding the bodies of Marine life. Studies have shown that calcified algae, coral polyps, shellfish, crustaceans and echinoderms are significantly less efficient at forming calcium carbonate shells and skeletons in acidified environments.

As a result of global warming, the upper surface layer of the ocean that absorbs CO2 from the atmosphere also becomes less dense due to the rising temperature, which weakens the material exchange between the surface layer and the middle and deep water, and makes the upper mixing layer of the ocean thinner, which is not conducive to the growth of phytoplankton.

mollusks

Some studies suggest that by 2030, the southern hemisphere's oceans will have a corrosive effect on snail shells. These mollusks are an important food source for salmon in the Pacific Ocean.

Effects on fish

Ocean acidification can hamper the growth and reproduction of coral reefs and lead to IQ declines in clownfish and small tropical fish. A new report in the proceedings of the national academy of sciences: simulating the acidity of seawater for the next 50 to 100 years, fish larvae in the most acidic waters instinctively avoid predators at first.

Experiments showed that only 10% of the same fish caught in 30 hours of real-world seawater acidity, all other things being equal, were caught. But when they were placed in acidified experimental waters near the Great Barrier Reef, they were killed by nearby predators within 30 hours.

Heavy rains

Acidification caused by the absorption of greenhouse gases by the ocean has led to the mass death of coral reefs on the continental shelf in the middle of the ocean, which has made low-lying island countries such as Kiribati and the maldives more vulnerable to heavy rainfall.

Human livelihood

It is estimated that in some waters the ocean will become so acidic that even the shells will start to dissolve. When shellfish disappear, other creatures that feed on them will have to find other food, and in fact humans will suffer.

The United Nations food and agriculture organization estimates that more than 500 million people depend on fishing and aquaculture as sources of protein and income. The effects of ocean acidification on Marine life must threaten the livelihoods of these populations.

Coral may disappear

In March 2013, a team of Japanese researchers reported in a new issue of the British journal nature climate change that the more acidified the ocean, the fewer corals with strong bones and the ability to make a reef, and the more soft sea cockscomb. If the acidification is too severe, corals could disappear by the end of the 21st century.

The team found that corals grew best when the water's pH averaged 8.1. At a pH of 7.8, it becomes crown-dominated. If the pH drops below 7.6, neither will survive.

Natural seawater has a stable pH between 7.9 and 8.4, while uncontaminated seawater has a pH between 8.0 and 8.3. The weak alkalinity of seawater is favorable for Marine organisms to use calcium carbonate to form shells.

The team notes that with seawater pH expected to be around 7.8 by the end of the century, and acidity significantly higher than normal, corals could disappear by then.

5Measures to prevent

At the international ocean acidification conference in October 2008, scientists at the conference noted that natural recovery of ocean acidification would take at least thousands of years, and that the only effective way to curb it would be to reduce global emissions of CO2 as soon as possible. Europe, the us and other countries are beginning to study countermeasures to curb ocean acidification, and China has listed ocean acidification as a key support direction.

On August 13, 2009, more than 150 scientists from 26 countries signed the MonacoDeclaration, which called on policymakers to stabilize carbon dioxide emissions within safe limits to avoid dangerous climate change and ocean acidification.

6Declaration of Monaco

On August 13, 2009, more than 150 top global Marine researchers gathered in Monaco, examine the acidification of the oceans, ocean acidification) the latest information, and sign the "Declaration of Monaco by Monaco (Declaration), the ocean acidification expressed concerns seriously hurt the global Marine ecosystem. The manifesto notes that the sea's pH levels are changing rapidly, 100 times faster than they have naturally in the past. The rapid change of Marine chemical substances in recent decades has seriously affected Marine life, food web, ecological diversity and fishery.

The declaration calls on policymakers to stabilise carbon dioxide emissions within safe limits to avoid dangerous climate change and ocean acidification. If carbon dioxide emissions in the atmosphere continue to rise, coral reefs will be unable to survive in most of the ocean by 2050, leading to permanent changes in commercial fishing stocks and threatening food security for millions of people.

7Application of HYDRO-BIOS's integrated water sampler in ocean acidification research

The integrated water sampler is used to collect mixed water samples containing nitrate, phosphate, silicate and other nutrient salts from the surface to the depth of 12 meters in the medium-sized experimental ecosystem. These water samples play a very important role in the study of nutrient salts in the later ecosystem.

International representative literature：

1.Edwin T.H.M. Peeters, Jean J.P. Gardeniers, Albert A. Koelmans,2000.Contribution of trace metals in structuring in situ macroinvertebrate community composition along a salinity gradient.Environmental Toxicology and Chemistry.19(4):1002-1010.

2.K. G. Schulz, R. G. J. Bellerby, C. P. D. Brussaard, J. Büdenbender, J. Czerny, A. Engel, M. Fischer, S. Koch-Klavsen, S. A. Krug, S. Lischka, A. Ludwig, M. Meyerh?fer, G. Nondal, A. Silyakova, A. Stuhr, and U. Riebesell,2012.Temporal biomass dynamics of an Arctic plankton bloom in response to increasing levels of atmospheric carbon dioxide.Biogeosciences Discussions.9:12543-12592.

3.Czerny, Jan, Schulz, Kai G., Boxhammer, Tim, Bellerby, R. G. J., Büdenbender, Jan, Engel, Anja, Krug, Sebastian, Ludwig, Andrea, Nachtigall, Kerstin, Nondal, G., Niehoff, B., Siljakova, A. and Riebesell, Ulf,2012.Element budgets in an Arctic mesocosm CO2 perturbation study.Biogeosciences Discussions.9 (8):11885-11924.

4.S. D. Archer, S. A. Kimmance, J. A. Stephens, F. E. Hopkins, R. G. J. Bellerby, K. G. Schulz, J. Piontek, and A. Engel,2012.Contrasting responses of DMS and DMSP to ocean acidification in Arctic waters.Biogeosciences Discussions.9:12803-12843.

5.Leu, E., Daase, M., Schulz, Kai G., Stuhr, Annegret and Riebesell, Ulf,2012.Effect of ocean acidification on the fatty acid composition of a natural plankton community.Biogeosciences Discussions.9 (7):8173-8197.

6.M. Sperling, J. Piontek, G. Gerdts, A. Wichels, H. Schunck, A.-S. Roy, J. La Roche, J. Gilbert, L. Bittner, S. Romac, U. Riebesell, and A. Engel,2012.Effect of elevated CO2 on the dynamics of particle attached and free living bacterioplankton communities in an Arctic fjord.Biogeosciences Discussions.9:10725-10755.

7.Kluijver, A. de,2012.Carbon flows in natural plankton communities in the Anthropocene.Geowetenschappen Proefschriften.1-118.

8.K. G. Schulz, U. Riebesell,2012.Diurnal changes in seawater carbonate chemistry speciation at increasing atmospheric carbon dioxide.Marine Biology.DOI 10.1007/s00227-012-1965-y.

9.J. Hua, W.H. Hwang,2012.Effects of voyage routing on the survival of microbes in ballast water.Ocean Engineering.42:165-175.

10."T. Tanaka, S. Alliouane, R. G. B. Bellerby, J. Czerny, A. de Kluijver, U. Riebesell6, K. G. Schulz,

A. Silyakova, and J.-P. Gattuso",2013.Effect of increased pCO2 on the planktonic metabolic balance during a mesocosm experiment in an Arctic fjord.Biogeosciences(BG).10:315–325.

11.A. de Kluijver, K. Soetaert, J. Czerny, K. G. Schulz, T. Boxhammer, U. Riebesell, and J. J. Middelburg,2013.A 13C labelling study on carbon fluxes in Arctic plankton communities under elevated CO2 levels.Biogeosciences(BG).10:1425-1440.

12.Czerny, Jan, Schulz, Kai G., Ludwig, Andrea and Riebesell, Ulf,2013.A simple method for air–sea gas exchange measurements in mesocosms and its application in carbon budgeting.Biogeosciences(BG).10 (3):11989-12017.

13.F. E. Hopkins, S. A. Kimmance1, J. A. Stephens, R. G. J. Bellerby, C. P. D. Brussaard, J. Czerny, K. G. Schulz, and S. D. Archer,2013.Response of halocarbons to ocean acidification in the Arctic.Biogeosciences(BG).10:2331-2345.

14.Czerny, Jan, Schulz, Kai G., Boxhammer, Tim, Bellerby, R. G. J., Büdenbender, Jan, Engel, Anja, Krug, Sebastian, Ludwig, Andrea, Nachtigall, Kerstin, Nondal, G., Niehoff, B., Silyakova, A. and Riebesell, Ulf,2013.Implications of elevated CO2 on pelagic carbon fluxes in an Arctic mesocosm study – an elemental mass balance approach.Biogeosciences(BG).10 (5):3109-3125.

15.R. Zhang, X. Xia, S. C. K. Lau, C. Motegi, M. G. Weinbauer, and N. Jiao,2013.Response of bacterioplankton community structure to an artificial gradient of pCO2 in the Arctic Ocean.Biogeosciences(BG).10, 3679–3689, 2013.