Oceans acidification

Impacts of Ocean Acidification on Coral Reefs and Other Marine Calcifiers A Guide for Future Research, report of a workshop held 18-20 April 2005, St. Petersburg, FL, sponsored by NSF, NOAA, and the U.S. Geological Survey, 88 pp. 

Jacobson, M. Z. (2005). Studying ocean acidification with conservative, stable numerical schemes for nonequilibriumair—ocean exchange and ocean equibbrium chemistry. J. Geophys. Res. 110, D07302, doi 10.1029/2004JD005220. 

Raven, J., Caldeira, K., Elderfield, H., Hoegh-Guldberg, O., Liss, P., Riebesell, U., Shepherd, J., Turley, C., and Watson, A. (2005). Ocean acidification due to increasing atmospheric carbon dioxide. The Royal Society, London. 60 pp. 

In the near future we anticipate further progress in ocean acidification as a result of increased atmospheric CO2 concentrations (Caldeira and Wickett, 2003) with sea surface pH potentially reaching as low as 7.8, a decrease of 0.5 pH units since the middle of the 20th century. More extensive periods of stratification and a spreading of oxygen-minimum zones in the world s oceans are also expected. Each of these processes is likely to impact on the oceanic N-cycle and the role cyanobacteria play within these systems. Specifically, these climate induced changes are likely to have significant effects on the composition of marine cyanobacterial communities and hence on the N dynamics they carry out. 

Finally, we consider acidification mechanisms specific to the continents so that ocean acidification is not an issue. Both enhanced respiration by surviving plant roots and bacterial decomposition of dead biomass witliin soils following Uie impact may have increased soil carbonic acid concentrations and soil weathering. (Dead biomass is also a source of alkalinity as Ca and other cations are released into the soil solution, but this process neutralized only a fraction of Uie total carbonic acid produced.) The subsurface soil biomass presently contains 2 x 10 moles C, which, if multiplied by -4 in the late Cretaceous, may liave been able to supply just enough carbonic acid to explain the foram Sr data. However, nearly all of the subsurface soil biomass would liave to have been decomposed by bacteria. Furthermore, the vast majority of CO2 released in soils diffuses out of the soil and joins the atmosphere [27], The numbers for plant root respiration are even less favorable. Presently, respiration accounts for 0.5 X 10 mol C yr released in soils. In the post-K/T impact atmosphere photosyntliesis was very likely interrupted for at least several months by dust and aerosols [7,8], so surviving plants would have had to respire at four times present biomass. One year of respiration yielded 2 x 10 mol CO2, not enough to weather Sr even if the CO2 remained in the soil. 

Ocean acidification due to increasing atmospheric carbon dioxide . The Royal Society, Policy Document 12/05, 2005 June, ISBN 0 85403 617 2. 

Royal Society 2005. Ocean Acidification due to Increasing Atmospheric Carbon Dioxide. Clyvedon Press, Cardiff, UK. 

I.J., Weirig, M.-F., Yamanaka, Y. and Yool, A., 2005. Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms. Nature 437 681-686, doi 10.1038/nature04095. 

Our ability to predict the consequences of ocean acidification on coccolithophores is hampered by our... 

Munday PL, Dixson DL, Donelson JM, Jones GP, Pratchett MS, Devitsina GV, Dpving KB (2009) Ocean acidification impairs olfactory discrimination and homing of marine fish. Proc Natl Acad Sci U S A 106 1848-1852... 

Furthermore, CO2 uptake leads to so-called oceanic acidification. With a very good approximation (i.e. neglecting the carbonate concentration compared with that of bicarbonate), equation (2.130) can be reduced to ... 

Solutions that contain high concentrations (10 M or more) of a weak conjugate acid-base pair and that resist drastic changes in pH when small amounts of strong acid or strong base are added to them are called buffered solutions (or merely buffers). Human blood, for example, is a complex buffered solution that maintains the blood pH at about 7.4. (Section 17.2, Blood as a Buffered Solution ) Much of the chemical behavior of seawater is determined by its pH, buffered at about 8.1 to 8.3 near the surface. (Section 17.5, Ocean Acidification ) Buffers find many important applications in the laboratory and in medicine ( Figure 17.1). Many biological reactions occur at the optimal rates only when properly buffered. If you ever work in a biochemistry lab, you will very likely to have prepare specific buffers in which to run your biochemical reactions. 

Absorption of CO2 by the ocean plays a large role in global climate. Because carbon dioxide and water form carbonic acid, the H2CO3 concentration in the ocean increases as the water absorbs atmospheric CO2. Most of the carbon in the ocean, however, is in the form of HC03 and CO ions, which form a buffer system that maintains the ocean s pH between 8.0 and 8.3. The pH of the ocean is predicted to decrease as the concentration of CO2 in the atmosphere increases, as discussed in the Chemistry and Life box on ocean acidification in Section 17.5. 

When the impact of process scale is viewed from the planetary boundaries perspective, the inherent multicriteria nature of any sustainability assessment is indispensable. Even when only environmental LCA impacts are accounted for, studies have shown that certain boundaries have been crossed or are very close to the limit (i.e., with respect to climate change, biodiversity loss, and nitrogen and phosphorous cycles), while others are stiU reasonably well safeguarded (i.e., stratospheric ozone depletion, ocean acidification, and freshwater use) [64]. It is therefore possible that different production sectors may have an impact on different planetary boundaries some of which may be within or already outside their safe operating space. For instance, studies have indicated the severe impacts of plastic debris on marine organisms [65]. Thus, from a cradle-to-grave LCA perspective, fossil-based plastics production may have a more direct or at least a different kind of effect in terms of biodiversity compared to fossil-based fuel production, which is certainly in higher production scales. 

As an extension of this demonstration, the electrode can be exposed to a flask containing C02(g) to demonstrate ocean acidification by CO2 (Box 11-1). 

Reaction A is the same reaction by which ocean acidification (Box 11-1) can destroy marine life in the ocean. 

Ocean Acidification Process in which the pH (acidity) level of the Earth s oceans becomes more acidic because of the increase in atmospheric carbon dioxide. 

The CDR approach removes carbon dioxide from tbe atmosphere and sequesters it undei ound or in the ocean. Many consider this approach to be tbe more attractive of the two as it not only helps reduce global temperatures but also works to combat issues such as ocean acidification caused by escalating carbon dioxide levels. Conversely, SRM techniques have no effect on atmospheric carbon dioxide levels, instead using reflected sunlight to reduce global temperatures. 

COj is gas associated with ocean acidification, emitted from sources such as combustion, cement production, and respiration of animals, including people. The main source in urban areas is the motor vehicle and industry, especially power generation... 

This overall equation is the basis of a qualitative field test for carbonate minerals because the CO2 bubbles vigorously (Figure 19.11). Far more importantly, it indicates the potential destructive effect of ocean acidification on vast expanses of coral reefs (composed of calcium carbonate) as increased atmospheric CO2 dissolves in seawater and lowers its pH ... 

Acid stresses sea urchins, and they double their rate of evolution in response,. .. M. H. Pespeni et al. Evolutionary change during experimental ocean acidification. 2013. Proc Natl Acad Sci. 110(17), p. 6937. DOl 10.1073/pnas.l220673110. 

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