This is a lengthy pdf document of a powerpoint presentation that accompanies a talk by Dr. It is a good resource for background information about ocean acidification because it covers chemistry, carbon cycles, CO2 emmission, and focuses on the impacts of ocean acidification on coral reefs. If you are looking to fully understand these concepts, check this out.
Stanford University's virtual urchin website is a fun and engaging way to educate yourself about Ocean Acidification. The page titled Our Acidifying Ocean features interactive pages about different ocean acidification topics.
Some of the pages are designed to help refresh your memory about what acids and bases even are! Other pages have you graph changes to ocean acidity by year or by CO2 emissions. Other topics are: pH, ocean chemistry, calcifying marine organisms, and urchin life cycles.
The first activity is about the pH scale, and how to test solutions to determine whether they are acids or bases. The second activity simulates the chemical process of ocean acidification in a cup using human-generated carbon dioxide!
The third activity goes a step further and demonstrates the effects of ocean acidification on seashells using vinegar as the acid. The Chemistry Of Ocean Acidification. For instance, if acidification eliminates populations of smaller fishes, then fish-eating waterfowl such as the common loon Gavia immer and merganser Mergus merganser will suffer, as will piscivorous raptors such as osprey Pandion haliaetus.
At the same time, however, the extirpation of predatory fish could result in an increased abundance of aquatic insects and zooplankton, which improves the food resource for other waterfowl, such as mallard Anas platyrhynchos , black duck A. The breeding success of common loons was studied on 84 lakes in Ontario Alvo et al. These observations likely reflect the size of the fish populations in these lakes.
A study of 79 small lakes and ponds in New Brunswick found a larger biomass of aquatic invertebrates in the littoral zone shallow, near-shore in acidic waterbodies with pH 4. Five species of ducks that feed on invertebrates had an average of 3. The greater biomass of invertebrates in the acidic waterbodies was likely due to decreased predation because of a reduced fish community. Drain Lake in Nova Scotia was previously described as a highly acidic pH 4. Drain Lake is fishless but it has large populations of aquatic invertebrates and plants.
This habitat allows black ducks and ring-necked ducks to be more productive than is typical for lakes in the region Kerekes et al.
These treatments, known as liming, serve to reduce acidity, clarify the water, and improve the productivity of fish such as trout. Not surprisingly, considerable research has also been done on the use of liming treatments to improve the condition of lakes and other surface waters that have been acidified by atmospheric deposition.
Effects of liming on pH are illustrated in Figure Initially, the treated lakes had a pH of 4. Middle and Hannah Lakes had a fairly stable pH after treatment, but Lohi quickly drifted back to an acidic condition.
This difference reflects the sizes of the watersheds of the lakes — Lohi drains a relatively large area and flushes quickly, so its neutralization results are shorter lived. Note that fertilizing the lakes with phosphate, which stimulates the productivity of phytoplankton, also has an acid-neutralizing effect, although it is much smaller than what resulted from liming.
Effects of Liming Lakes. These lakes are located in the Sudbury region, and they were acidified by a combination of dry and wet atmospheric depositions. The times of treatment with neutralizing agents CaCO 3 or Ca OH 2 are indicated by arrows, and the addition of phosphate by solid dots. Source: Modified from Dillon et al. Initially, the treated lakes had a large decline in the productivity of phytoplankton and zooplankton. However, the phytoplankton biomass soon returned to the pre-liming condition, but with lingering changes in species composition.
The zooplankton recovered more slowly, and even after three years had not returned to the pre-liming abundance. In addition, fish kept in cages in the limed lakes suffered high rates of mortality. This was likely due to metal toxicity, because the lakes had been affected by fallout from the Sudbury smelters.
Although the aqueous concentrations of Al, Cu, Ni, and Zn all decreased after liming, because their solubility is greater in acidic water, they still remained high enough to stress fish and other biota.
In some regions of Scandinavia, liming is routinely used to treat large numbers of acidified lakes and rivers. This is done to mitigate the damage caused by acidification, especially to fish populations. By the late s, about thousand lakes in Sweden had been acidified by atmospheric deposition out of a total of thousand lakes , as had many streams and rivers.
Of the acidified waterbodies, more than 7, lakes and 14, km of flowing water are being treated with liming agents; about thousand tonnes of powdered limestone is used each year.
Typically, the liming treatment must be repeated on a three-year rotation. In Norway, about 3, waterbodies have been limed State of the Environment Norway, Liming has been conducted much less extensively in North America, largely because the programs are expensive and environmental priorities are different from Scandinavia.
Research on liming has shown that acidified surface waters can be neutralized. Nevertheless, it must be understood that liming treats the symptoms of damage in acidified ecosystems, but not the causes of the acidification. Moreover, liming itself represents an environmental stress that transforms a waterbody from one polluted condition to another that is still damaged, but less toxic.
Liming causes a large change in acid-adapted ecosystems, which is followed by changes in species abundances as new communities develop. In general, the most important benefit of liming is that less-acidic waters can support fish, whereas acidic waters cannot. However, liming is not a long-term solution to the acidification of fresh waters. In part, this is because waterbodies must be periodically re-treated as the liming materials are consumed or flushed out of the system.
To some degree, acidified waterbodies may also be managed by treating them with fertilizer to stimulate their productivity, as was previously examined for Drain Lake. Fertilized acidic lakes can sustain a large biomass of phytoplankton, macrophytes, and invertebrates.
Waterfowl may thrive in this habitat, even if fish cannot be sustained because of the acidic conditions. However, it is not necessarily appropriate to create large numbers of highly productive lakes. For example, where recreational swimming is an important activity, abundant algae and macrophytes are considered a nuisance. This lake near a smelter at Sudbury was acidified to a pH less than 4.
Since this photo was taken in , SO 2 pollution in the vicinity has been greatly abated, and that has allowing the lake to become less acidic. Today, it again provides habitat for species that are intolerant of severe acidity. Ultimately, the extensive damage caused by acidifying deposition from the atmosphere can only be resolved by reducing the emissions of acid-forming gases. Although this fact is intuitively clear, the issue of emissions reduction remains controversial for the following reasons:.
Not surprisingly, industries and regions that are responsible for large emissions of acid-forming gases have tended to resist the imposition of substantial legislated reductions of their releases. In general, they argue that the scientific justification for the reductions is not yet convincing, while the costs of controls are known to be large and potentially disruptive of the economy.
In addition, how low should the rates of atmospheric deposition of sulphur and nitrogen compounds be, in order to avoid further acidification of sensitive surface waters or to allow their recovery? The critical rates of deposition of acidifying compounds are influenced, in part, by the vulnerability of the receiving ecosystems — areas with shallow, nutrient-poor soil can sustain much lower inputs of acidifying substances than areas rich in calcium.
A critical load is the wet and dry deposition of sulphur and nitrogen compounds that can be tolerated without causing acidification. Source: Environment Canada Although there are many uncertainties about the specific causes and magnitude of the damage caused by the atmospheric deposition of acidifying substances, it is obvious that what goes up emissions of acid-precursor gases must eventually come down as acidifying deposition.
This common sense idea is supported by a great deal of scientific evidence. This knowledge, combined with public awareness and concern about acidification in many countries, has spurred politicians to begin to take effective action. In , the governments of Canada and the United States signed a binational treaty aimed at reducing acidifying deposition in both countries. This agreement, known as the Canada—U. Air Quality Agreement, calls for large expenditures by industries and governments to substantially reduce the emissions of air pollutants, especially SO 2.
These cutbacks are on top of reductions of emissions that both countries had already achieved during the s. In the United States, emissions of SO 2 have decreased from For comparison, the Canadian emissions of SO 2 decreased from 4. The built environment may also be damaged by acidifying deposition from the atmosphere. For example, structures made of limestone, marble, or sandstone become chemically destabilized and eroded by the dry deposition of SO 2 and NO x and by acidic precipitation.
These pollutants are seriously damaging many famous artifacts of cultural heritage, such as this ancient citadel known as the Acropolis in Athens, Greece. A major component of the U. From the environmental perspective, this marketplace for emissions is a logical instrument because the atmosphere is a common-property resource that is owned and affected by everyone, so any changes in the release of pollutants whether increases or decreases have a global effect.
In essence, a company whose emissions are smaller than its allowance can realize a profit by selling its credits, while another that has exceeded its target incurs costs. Those costs may be paid either by purchasing emissions credits or by taking action to reduce the emissions, such as installing SO 2 -removal technology, switching to a low-sulphur fuel, or in extreme cases, shutting down particularly dirty facilities. The flexibility associated with these options is considered by many economists and politicians to have been an important benefit of the system of emissions trading.
Nevertheless, the establishment of a marketplace that commodifies the release of SO 2 does liberate many companies from the expensive investments that would be required to achieve tangible reductions of their emissions. This fact has engendered controversy, as has the potential establishment of a global marketplace for tradable emissions of greenhouse gases under the Kyoto Protocol Chapter In any event, are the cuts in emissions large enough to achieve their intended effect of preventing and repairing the acidification of ecosystems?
According to a science assessment carried out by Environment Canada, the reductions of SO 2 emissions have resulted in lower rates of acidifying deposition in Canada based on a comparison of data for — and —; Environment Canada, A similar conclusion was reached by the U.
Environmental Protection Agency in its own science assessment of the issue Furthermore, not much action has been taken to reduce the emissions of NO x , and this appears to be working against the environmental benefits associated with increased control of SO 2.
It is crucial that future regulatory actions include reduced emissions of both SO 2 and NO x and that acid rain and its environmental damage continues to be monitored. The air-pollution treaty between Canada and the United States is a helpful accomplishment. Although there have been reductions in the acidity of precipitation and surface waters in some areas, it appears that the reductions of SO 2 emissions are not large enough to fully mitigate many of the damages caused by acidifying deposition.
So far, extremely large areas of terrain continue to be affected by acidification caused by Atmospheric deposition. Improving trends in the chemistry of precipitation and streamwater at Hubbard Brook, NH, a monitoring location with outstanding longer-term data of this sort of data, are shown in Figure The precipitation data show that the acidity of precipitation is decreasing the pH is increasing , and that the concentrations of sulphate and nitrate are also decreasing.
The reduction of sulphate concentrations is especially large, and likely reflects the fact that regulatory controls have concentrated on SO 2 emissions the main precursor of sulphate more so that on NO x the precusors of nitrate.
The streamwater data also show decreasing acidity and sulphate concentration, as well as a steady decrease in the concentrations of calcium. The latter observation may reflect a progressive loss of calcium from these watersheds, which represents a degradation of the ability of the system to provide acid-neutralizing capability agains future inputs of acidifying substances.
Trends in the chemistry of a precipitation and b streamwater chemistry at Hubbard Brook, NH. Source: data obtained from Gene E. Mellon Foundation. Some lakes are also benefiting from reduced sulphate loading. Across eastern Canada, however, 0. It must be recognized that pollution control is extremely expensive.
Because of this cost, policies that favour reduced emissions of SO 2 and NO x may not be able to survive the frequent challenges mounted by politicians, economists, and business people who do not believe that such actions are necessary.
In less-wealthy countries, the political focus is mostly on industrial and economic growth. As soon as possible, much more political and scientific attention must be devoted to the problems of acidifying deposition and other kinds of pollution in eastern Europe, Russia, China, India, Southeast Asia, Mexico, and other rapidly growing economies. In those countries, emissions of SO 2 , NO x , and other important airborne pollutants are galloping out of control. Acidification is a natural process that occurs as ecosystems interact with climatic and biological influences, for example in bogs and coniferous forest.
Acidification is also caused by anthropogenic influences, particularly emissions of SO 2 and NO x , which oxidize to form acids while in the atmosphere or after they are dry-deposited to ecosystems. Aquatic and terrestrial ecosystems that are vulnerable to acidification have little acid-neutralizing capacity, largely because of small amounts of calcium and magnesium carbonates in their soil, sediment, or rocks.
Low-alkalinity freshwaters are particularly at risk of acidification by atmospheric deposition. When a waterbody acidifies to a pH less than about 6. Acidifying influences also damage the built environment by eroding materials made of limestone, marble, and certain metals such as copper.
Although some of the ecological damage caused by acidification to surface waters can be mitigated by liming, this treatment has to be repeated, typically on about a three-year rotation.
The best way to avoid the environmental problems associated with acidifying deposition is to reduce the emissions of the key acid-precursor gases SO 2 and NO x.
To a substantial degree, this is being done in wealthy countries, including Canada. However, rapidly growing economies, such as China and India, are not paying much attention to this environmental problem, and it is rapidly becoming worse as they aggressively increase their supply of commercial energy by burning sulphurous fossil fuels, particularly coal.
Alvo, R. Hussell, and M. The breeding success of common loons Gavia immer in relation to alkalinity and other lake characteristics in Ontario. Canadian Journal of Zoology, Baker, L. Herlihy, P. Acidic lakes and streams in the United States: The role of acidic deposition. Science, Beamish, R. Journal of the Fisheries Research Board of Canada, Brand, D. Kehoe, and M. Coniferous afforestation leads to soil acidification in central Ontario. Canadian Journal of Forest Research, Brodin, Y.
Acidification and critical loads in Nordic countries: A background. Ambio, Buso, D. Likens, and J. Chan, W. Vet, C. Ro, A. Tang, and M. Long-term precipitation quality and wet deposition in the Sudbury basin. Atmospheric Environment, Crocker, R. Soil development in relation to vegetation and surface age at Glacier Bay, Alaska. Journal of Ecology, Dale, J. Freedman, and J. Acidity and associated water chemistry of amphibian habitats in Nova Scotia.
Dillon, P. Jefferies, W. Snyder, R. Reid, N. Yan, D. Evans, J. Moss, and W. Acid Rain in South-Central Ontario. Yan, W. Schieder, and N. Acidic lakes in Ontario, Canada: Characterization, extent, and responses to base and nutrient additions. Archives of Hydrobiology, Suppl. Dixit, S. Dixit, and J. Multivariate environmental inferences based on diatom assemblages from Sudbury Canada lakes.
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Environment Canada, Ottawa, ON. Canadian Acid Deposition Science Assessment Accessed January, Air Trends. Findlay, D. Phytoplankton community responses to acidification of Lake , Experimental Lakes Area, northwestern Ontario. Water, Air, and Soil Pollution, Freda, J. Sadinski, and W. Long term monitoring of amphibians populations with respect to the effects of acidic deposition. Freedman, B. Environmental Ecology.
Ion mass balances and seasonal fluxes from four acidic brownwater streams in Nova Scotia. Canadian Journal of Fisheries and Aquatic Science, Gerhardsson, L. Oskarsson, and S. Acid precipitation — effects on trace elements and human health. Science of the Total Environment, Godbold, D. Huttermann eds. Effects of Acid Rain on Forest Processes. Wiley-Liss, Hoboken, NJ. Harvey, H.
Historical fisheries changes related to surface water pH changes in Canada. Henriksen, A. Acidification of freshwaters — a large scale titration. Drablos and A. Tollan, eds. Jeffries, D. Brydges, P. Dillon, and W. Environmental Monitoring and Assessment, Joskow, P.
Ellerman, J. Montero, R. Schmatensee, and E. Markets for Clean Air: The U. Acid Rain Program. Kelly, C. Rudd, A. Furutani, and D. Effects of lake acidification on rates of organic matter decomposition in sediments. Limnology and Oceanography, Kerekes, J. Physical, chemical, and biological characteristics of three watersheds in Kejimkujik National Park, Nova Scotia.
Archives of Environmental Contamination and Toxicology, Freedman, G. Howell, and P. Comparison of the characteristics of an acidic eutrophic and an acidic oligotrophic lake near Halifax, Nova Scotia. Water Pollution Research Journal of Canada, Lacroix, G. Responses of juvenile Atlantic salmon Salmo salar to episodic increases in acidity of Nova Scotia rivers. Linzon, S. Soil resampling and pH measurements after an year period in Ontario. Lovett, G.
Reiners, and R. Cloud droplet deposition in subalpine balsam fir forests: Hydrological and chemical budgets. Malley, D. Findlay, and P. Ecological effects of acid precipitation on zooplankton.
Mills, K. Fish population responses to experimental acidification of a small Ontario lake. Hendry, ed. Measurements of the f CO2 of discrete seawater samples is somewhat more demanding than measurements of spectrophotometric pH, and f CO2 sample throughput is somewhat slower. If three types of measurements are possible, the third selected parameter should be TA. Differences between measured TA and calculated TA allow insights into the local significance of organic alkalinity.
Only when all four measurements are possible should f CO2 and pH both be included in the measurement suite. This duo is generally not the best choice as an input pair for calculating carbonate concentrations. Marine chemical systems and biota are experiencing ocean carbonation and acidification under in situ conditions, but in situ measurements are not yet routine. Many measurements are still made by retrieving seawater samples from depth and then analyzing those samples in a laboratory, either on ships or on land.
Without in situ measurements, the calculation of CO 2 system variables e. This point is subtle but important. DIC is typically directly measured. TA may be either directly measured or calculated—i. Both calculations are subject to error unless all alkalinity equilibria including organic alkalinity are fully characterized with respect to variations in S , T , and P. Measuring either pH in situ or f CO2 in situ to pair with measurements of DIC would provide the most straightforward route to the direct calculation of other in situ quantities.
For example, in situ [CO 3 2— ] can be calculated from DIC and in situ pH without having to account for organic alkalinity, borate alkalinity, and other noncarbonate alkalinity contributions. The oceans are vast, and research expeditions are expensive. Improving the spatial and temporal resolution of ocean sampling programs will require ongoing development of underwater platforms and sensors. For shipboard sampling, sensors can be mounted on the rosettes used to collect seawater samples.
Real-time profiles of S , T , P , and oxygen, with vertical resolutions on the order of 1 m are typically collected this way. Vertical profiles of pH 72 have been similarly obtained but are not routine.
Some state-of-the-art shipboard and laboratory procedures are not adaptable to underwater deployment. For example, coulometric instrumentation used to measure DIC is ill-suited to in situ analysis, and potentiometric procedures suitable for shipboard and laboratory TA analyses are quite challenging for in situ TA applications. Spectrophotometric techniques possess many of the characteristics needed for underwater instrumentation.
As a result, these methods have been used for in situ measurements of all four keystone CO 2 system parameters. The general spectrophotometric approach, now used in marine CO 2 system analyses for more than two decades, entails measuring the colors i. Collectively, these dyes allow for observations over a pH range of approximately 2—9. Purified indicator 69 should be used for all procedures.
This procedure is straightforward and has been used for shipboard and in situ 58, 66, 84 work: dye is added to a seawater sample and the resulting color absorbance is measured at specified wavelengths.
If a well-characterized purified indicator is used, no field calibration is required. Purification procedures have been developed for two indicators appropriate for direct measurements of seawater pH: meta cresol purple mCP and cresol red.
In situ spectrophotometric f CO2 measurements 84, 85 rely on equilibration of CO 2 across a semipermeable membrane that separates a natural seawater sample from a synthetic solution of known TA. The postequilibration pH of this reagent is measured spectrophotometrically, and f CO2 is calculated from the TA—pH pair. Such measurements of f CO2 are free of the need for periodic calibration during field deployments.
Spectrophotometric DIC measurements rely on equilibration of CO 2 aq across a semipermeable membrane that separates an acidified seawater sample from a synthetic solution of known TA. The postequilibration pH of the synthetic reagent is measured spectrophotometrically, and CO 2 aq is calculated from the TA—pH pair. For in situ instruments, 80 the acidified seawater offers the important advantage of effectively preventing biofouling, perhaps the primary impediment to marine sensor endurance.
When sulfonephthalein dye is dissolved in the acid used for TA titrations, absorbance measurements can provide a direct measure of not only solution pH but also the acid—seawater mixing ratio. Bromocresol green has been used in this way for in situ TA measurements.
Seawater TA could then be calculated from the measured pH of the sample and the known f CO2 of the synthetic solution or gas. In-water methods to measure organic alkalinity are needed but are likely to be challenging. New in situ capabilities are rapidly being developed. In most cases the new technologies do not provide internally calibrated measurements, but they do provide other advantages that should engender their widespread use in ocean acidification studies.
Ion selective field effect transistors ISFETs provide high-frequency pH measurements with low power consumption 88 and very slow rates of measurement drift.
The instruments are calibrated once per profile at their point of deepest descent, where pH changes are very small. Deeper deployments may be possible with the use of novel nanocomposite membranes. Conductometric procedures 92 appear to be well suited to determinations of DIC when high-frequency e. CO 2 aq in an acidified sample is equilibrated across a membrane that separates ambient seawater from a synthetic inner alkaline solution, lowering the inner-solution concentration of highly mobile OH — and increasing the concentration of much less conductive HCO 3 —.
This approach requires the use of multiple standard solutions, but the device is inherently simple with relatively low power requirements. CO 2 aq is equilibrated across a membrane that separates ambient seawater from an inner chamber where gas is circulated through an optical cell that includes a temperature-stabilized, single-beam, dual-wavelength NDIR detector.
Baseline measurements CO 2 -free are periodically made by scrubbing the gas stream with an internal soda-lime cartridge, thus allowing for compensation of drift in sensor response. Ultraviolet UV absorbance spectroscopy can be used for direct measurements of CO 3 2— in seawater. As such, UV spectrometry has the potential to directly provide in situ carbonate ion concentrations.
CO 2 system observations require either prompt analysis or demonstration of negligible change in the time between sample collection and analysis. In biologically productive coastal waters, where the threat of postcollection alteration is high, the need for speed is heightened.
When in situ measurements are not possible, high-quality portability may be the next best thing. Spectrophotometric methods are particularly well suited to CO 2 system analyses because of their inherent calibration characteristics. Recently developed instrument components e.
These devices are also amenable to analysis of the alkalinities of coastal seawater. Inexpensive yet precise and accurate hand-held CO 2 system devices may be helpful in building coastal citizen-science networks that could complement state-of-the-art autonomous monitoring networks.
Such devices may also prove useful in commercial applications e. Frontier Measurements. Some of the greatest future advances in marine biogeochemistry are likely to entail not only additional CO 2 system capabilities e.
Notable examples of such ecologically influential variables include the concentrations and species distributions of iron Figure 3 and copper. Like iron, copper is an essential element for many marine microorganisms, but even subnanomolar levels of free uncomplexed cupric ions can be excessive and toxic. Dissolved metal concentrations and species distributions in seawater are influenced by a number of acidity-dependent reactions e.
For waters with relatively high dissolved metal concentrations e. One such method has provided a shipboard iron detection limit of 0. These methods do not have the resolution and low detection limits required for measurements in the oligotrophic ocean. Promising in situ methods with substantially improved limits of detection include the use of dissolved iron to catalyze a spectrophotometrically monitored reaction.
Characterizing trace metal speciation in situ presents an even greater challenge than measuring total concentrations. At present, laboratory-based studies of iron complexation by diverse organic ligands constitute research at the frontier of marine science.
Voltametric procedures, which have proven useful in lab-based assessments of marine trace metal speciation, , constitute important candidate methods for eventual in situ analyses. In this era of ocean change, marine scientists and engineers must tackle the challenge of not only developing new individual sensors physical, chemical, and biological but also obtaining field observations within the richest possible context.
Observations of changes in ocean productivity, on a variety of time scales, should be interpreted in view of not only ocean physics e. Increasing the availability and diversity of marine sensors to the extent that appropriate suites of sensors can be widely and flexibly applied to ocean observations may be among the largest of challenges for future ocean observing systems.
Author Information. Petersburg, Florida , United States ; Email: [email protected]. The authors declare no competing financial interest. Natural and anthropogenic changes in atmospheric CO 2 over the last years from air in Antarctic ice and firn J. Etheridge, D.
American Geophysical Union. A record of atm. CO2 mixing ratios from A. The enclosed air has unparalleled age resoln. The CO2 data overlap with the record from direct atm. The effects of diffusion in the firm on the CO2 mixing ratio and age of the ice core air were detd. The uncertainty of the ice core CO2 mixing ratios is 1. Preindustrial CO2 mixing ratios were in the range ppm, with the lower levels during A. Natural CO2 variations of this magnitude make it inappropriate to refer to a single preindustrial CO2 level.
Major CO2 growth occurred over the industrial period except during A. Trends in Atmospheric Carbon Dioxide.
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Global Carbon Project In Ocean Acidification ; Gattuso, J. Risks to coral reefs from ocean carbonate chemistry changes in recent earth system model projections Environ. Impacts of ocean acidification on marine organisms: Quantifying sensitivities and interaction with warming Global Change Biol. Global change biology , 19 6 , ISSN: Ocean acidification represents a threat to marine species worldwide, and forecasting the ecological impacts of acidification is a high priority for science, management, and policy.
As research on the topic expands at an exponential rate, a comprehensive understanding of the variability in organisms' responses and corresponding levels of certainty is necessary to forecast the ecological effects. Here, we perform the most comprehensive meta-analysis to date by synthesizing the results of studies examining biological responses to ocean acidification. The results reveal decreased survival, calcification, growth, development and abundance in response to acidification when the broad range of marine organisms is pooled together.
However, the magnitude of these responses varies among taxonomic groups, suggesting there is some predictable trait-based variation in sensitivity, despite the investigation of approximately new species in recent research.
The results also reveal an enhanced sensitivity of mollusk larvae, but suggest that an enhanced sensitivity of early life history stages is not universal across all taxonomic groups. In addition, the variability in species' responses is enhanced when they are exposed to acidification in multi-species assemblages, suggesting that it is important to consider indirect effects and exercise caution when forecasting abundance patterns from single-species laboratory experiments.
Furthermore, the results suggest that other factors, such as nutritional status or source population, could cause substantial variation in organisms' responses. Last, the results highlight a trend towards enhanced sensitivity to acidification when taxa are concurrently exposed to elevated seawater temperature.
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The process of ocean acidification is well documented in field data, and the rate will accelerate over this century unless future CO2 emissions are curbed dramatically. Acidification alters seawater chemical speciation and biogeochemical cycles of many elements and compounds.
One well-known effect is the lowering of calcium carbonate saturation states, which impacts shell-forming marine organisms from plankton to benthic molluscs, echinoderms, and corals. Many calcifying species exhibit reduced calcification and growth rates in laboratory experiments under high-CO2 conditions. Ocean acidification also causes an increase in carbon fixation rates in some photosynthetic organisms both calcifying and noncalcifying.
The potential for marine organisms to adapt to increasing CO2 and broader implications for ocean ecosystems are not well known; both are high priorities for future research. Although ocean pH has varied in the geological past, paleo-events may be only imperfect analogs to current conditions. Ocean acidification and climate change: Advances in ecology and evolution Philos. Philosophical transactions of the Royal Society of London. The geological record of ocean acidification Science , — Google Scholar There is no corresponding record for this reference.
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To date, these studies show that coral calcification varies with carbonate ion availability which, in turn controls aragonite satn. They also reveal synergies between acidification and the better understood role of elevated temp.
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The relationship between cupric ion activity and the toxicity of copper to phytoplankton J. Growth of the estuarine diatom Thalassiosira pseudonana and of the estuarine alga Nannochloris atomus was inhibited by cupric ions, the effect being related to cupric ion activity and not to total Cu concn. The cupric ion activity was altered independently of the total Cu concn. Thus, the toxicity of Cu to phytoplankton in natural marine environments depends on pH and the degree of Cu complexation by natural org.
Copper sensitivity of Gonyaulax tamarensis Limnol. The Cu sensitivity of the dinoflagellate G. Two short term responses of the organism to Cu toxicity were rapid loss of motility and reduced photosynthetic C fixation. Cu addns.
EDTA equilibrated with the chelator relatively slowly, resulting in misleading short term data. Variations in Mn concns. Cells of G. Nonmotile cells do not divide or grow larger. Furthermore, this toxicity occurs at the calcd. Cu activity of natural waters, assuming only inorg. Cu complexation. Thus org. The influence of aqueous iron chemistry on the uptake of iron by the coastal diatom Thalassiosira weissflogii Limnol. Fe uptake by the coastal diatom Thalassiosira weissflogii was measured by a technique that exploits the Fe III -reducing property of ascorbate [] to dissolve filterable colloidal Fe.
For the well-defined chem. An even greater enhancement resulted from the addn. In the absence of chelators, Fe uptake rates appeared to depend on the total Fe concn. A satd. Uptake rates measured in the presence of metabolic inhibitors are consistent with the hypothesis that a membrane-bound metal binding complex termed phytotransferrin transfers Fe across the membrane by a process not directly coupled to photosynthetic or respiratory activity.
On the basis of all the expts. Measurement of free cupric ion concentration in seawater by a ligand competition technique involving copper sorption onto C18 SEP-PAK cartridges Limnol. From these values and from computed and exptl. The remainder, These results are in general agreement with other studies, using several techniques, of Cu complexation in seawater.
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