Food supply confers calcifiers resistance to ocean acidification.

PubMed

Ramajo, Laura; Pérez-León, Elia; Hendriks, Iris E; Marbà, Núria; Krause-Jensen, Dorte; Sejr, Mikael K; Blicher, Martin E; Lagos, Nelson A; Olsen, Ylva S; Duarte, Carlos M

2016-01-18

Invasion of ocean surface waters by anthropogenic CO2 emitted to the atmosphere is expected to reduce surface seawater pH to 7.8 by the end of this century compromising marine calcifiers. A broad range of biological and mineralogical mechanisms allow marine calcifiers to cope with ocean acidification, however these mechanisms are energetically demanding which affect other biological processes (trade-offs) with important implications for the resilience of the organisms against stressful conditions. Hence, food availability may play a critical role in determining the resistance of calcifiers to OA. Here we show, based on a meta-analysis of existing experimental results assessing the role of food supply in the response of organisms to OA, that food supply consistently confers calcifiers resistance to ocean acidification.

Food supply confers calcifiers resistance to ocean acidification

NASA Astrophysics Data System (ADS)

Ramajo, Laura; Pérez-León, Elia; Hendriks, Iris E.; Marbà, Núria; Krause-Jensen, Dorte; Sejr, Mikael K.; Blicher, Martin E.; Lagos, Nelson A.; Olsen, Ylva S.; Duarte, Carlos M.

2016-01-01

Invasion of ocean surface waters by anthropogenic CO2 emitted to the atmosphere is expected to reduce surface seawater pH to 7.8 by the end of this century compromising marine calcifiers. A broad range of biological and mineralogical mechanisms allow marine calcifiers to cope with ocean acidification, however these mechanisms are energetically demanding which affect other biological processes (trade-offs) with important implications for the resilience of the organisms against stressful conditions. Hence, food availability may play a critical role in determining the resistance of calcifiers to OA. Here we show, based on a meta-analysis of existing experimental results assessing the role of food supply in the response of organisms to OA, that food supply consistently confers calcifiers resistance to ocean acidification.

Food supply confers calcifiers resistance to ocean acidification

PubMed Central

Ramajo, Laura; Pérez-León, Elia; Hendriks, Iris E.; Marbà, Núria; Krause-Jensen, Dorte; Sejr, Mikael K.; Blicher, Martin E.; Lagos, Nelson A.; Olsen, Ylva S.; Duarte, Carlos M.

2016-01-01

Invasion of ocean surface waters by anthropogenic CO2 emitted to the atmosphere is expected to reduce surface seawater pH to 7.8 by the end of this century compromising marine calcifiers. A broad range of biological and mineralogical mechanisms allow marine calcifiers to cope with ocean acidification, however these mechanisms are energetically demanding which affect other biological processes (trade-offs) with important implications for the resilience of the organisms against stressful conditions. Hence, food availability may play a critical role in determining the resistance of calcifiers to OA. Here we show, based on a meta-analysis of existing experimental results assessing the role of food supply in the response of organisms to OA, that food supply consistently confers calcifiers resistance to ocean acidification. PMID:26778520

Trends in Surface Water Chemistry in Acidified Areas in Europe and North America from 1990 to 2008

EPA Science Inventory

Acidification of lakes and rivers is still an environmental concern despite reduced emissions of acidifying compounds. We analyzed trends in surface water chemistry of 173 acid-sensitive sites from 12 regions in Europe and North America. In 11 of 12 regions, non-marine sulphate (...

Baseline Monitoring of the Western Arctic Ocean Estimates 20% of Canadian Basin Surface Waters Are Undersaturated with Respect to Aragonite

PubMed Central

Robbins, Lisa L.; Wynn, Jonathan G.; Lisle, John T.; Yates, Kimberly K.; Knorr, Paul O.; Byrne, Robert H.; Liu, Xuewu; Patsavas, Mark C.; Azetsu-Scott, Kumiko; Takahashi, Taro

2013-01-01

Marine surface waters are being acidified due to uptake of anthropogenic carbon dioxide, resulting in surface ocean areas of undersaturation with respect to carbonate minerals, including aragonite. In the Arctic Ocean, acidification is expected to occur at an accelerated rate with respect to the global oceans, but a paucity of baseline data has limited our understanding of the extent of Arctic undersaturation and of regional variations in rates and causes. The lack of data has also hindered refinement of models aimed at projecting future trends of ocean acidification. Here, based on more than 34,000 data records collected in 2010 and 2011, we establish a baseline of inorganic carbon data (pH, total alkalinity, dissolved inorganic carbon, partial pressure of carbon dioxide, and aragonite saturation index) for the western Arctic Ocean. This data set documents aragonite undersaturation in ∼20% of the surface waters of the combined Canada and Makarov basins, an area characterized by recent acceleration of sea ice loss. Conservative tracer studies using stable oxygen isotopic data from 307 sites show that while the entire surface of this area receives abundant freshwater from meteoric sources, freshwater from sea ice melt is most closely linked to the areas of carbonate mineral undersaturation. These data link the Arctic Ocean’s largest area of aragonite undersaturation to sea ice melt and atmospheric CO2 absorption in areas of low buffering capacity. Some relatively supersaturated areas can be linked to localized biological activity. Collectively, these observations can be used to project trends of ocean acidification in higher latitude marine surface waters where inorganic carbon chemistry is largely influenced by sea ice meltwater. PMID:24040074

Baseline monitoring of the western Arctic Ocean estimates 20% of the Canadian Basin surface waters are undersaturated with respect to aragonite

USGS Publications Warehouse

Robbins, Lisa L.; Wynn, Jonathan G.; Lisle, John T.; Yates, Kimberly K.; Knorr, Paul O.; Byrne, Robert H.; Liu, Xuewu; Patsavas, Mark C.; Azetsu-Scott, Kumiko; Takahashi, Taro

2013-01-01

Marine surface waters are being acidified due to uptake of anthropogenic carbon dioxide, resulting in surface ocean areas of undersaturation with respect to carbonate minerals, including aragonite. In the Arctic Ocean, acidification is expected to occur at an accelerated rate with respect to the global oceans, but a paucity of baseline data has limited our understanding of the extent of Arctic undersaturation and of regional variations in rates and causes. The lack of data has also hindered refinement of models aimed at projecting future trends of ocean acidification. Here, based on more than 34,000 data records collected in 2010 and 2011, we establish a baseline of inorganic carbon data (pH, total alkalinity, dissolved inorganic carbon, partial pressure of carbon dioxide, and aragonite saturation index) for the western Arctic Ocean. This data set documents aragonite undersaturation in ~20% of the surface waters of the combined Canada and Makarov basins, an area characterized by recent acceleration of sea ice loss. Conservative tracer studies using stable oxygen isotopic data from 307 sites show that while the entire surface of this area receives abundant freshwater from meteoric sources, freshwater from sea ice melt is most closely linked to the areas of carbonate mineral undersaturation. These data link the Arctic Ocean’s largest area of aragonite undersaturation to sea ice melt and atmospheric CO2 absorption in areas of low buffering capacity. Some relatively supersaturated areas can be linked to localized biological activity. Collectively, these observations can be used to project trends of ocean acidification in higher latitude marine surface waters where inorganic carbon chemistry is largely influenced by sea ice meltwater.

Sensitivity to acidification of subalpine ponds and lakes in north-western Colorado

USGS Publications Warehouse

Campbell, D.H.; Muths, E.; Turk, J.T.; Corn, P.S.

2004-01-01

Although acidifying deposition in western North America is lower than in many parts of the world, many high-elevation ecosystems there are extremely sensitive to acidification. Previous studies determined that the Mount Zirkel Wilderness Area (MZWA) has the most acidic snowpack and aquatic ecosystems that are among the most sensitive in the region. In this study, spatial and temporal variability of ponds and lakes in and near the MZWA were examined to determine their sensitivity to acidification and the effects of acidic deposition during and after snowmelt. Within the areas identified as sensitive to acidification based on bedrock types, there was substantial variability in acid-neutralizing capacity (ANC), which was related to differences in hydrological flowpaths that control delivery of weathering products to surface waters. Geological and topographic maps were of limited use in predicting acid sensitivity because their spatial resolution was not fine enough to capture the variability of these attributes for lakes and ponds with small catchment areas. Many of the lakes are sensitive to acidification (summer and autumn ANC < 100 µeq L−1), but none of them appeared to be threatened immediately by episodic or chronic acidification. In contrast, 22 ponds had minimum ANC < 30 µeq L−1, indicating that they are extremely sensitive to acidic deposition and could be damaged by episodic acidification, although net acidity (ANC < 0) was not measured in any of the ponds during the study. The lowest measured pH value was 5·4, and pH generally remained less than 6·0 throughout early summer in the most sensitive ponds, indicating that biological effects of acidification are possible at levels of atmospheric deposition that occurred during the study. The aquatic chemistry of lakes was dominated by atmospheric deposition and biogeochemical processes in soils and shallow ground water, whereas the aquatic chemistry of ponds was also affected by organic acids and biogeochemical processes in the water column and at the sediment–water interface. These results indicate that conceptual and mechanistic acidification models that have been developed for lakes and streams may be inadequate for predicting acidification in less-understood systems such as ponds.

Bottom Water Acidification and Warming on the Western Eurasian Arctic Shelves: Dynamical Downscaling Projections

NASA Astrophysics Data System (ADS)

Wallhead, P. J.; Bellerby, R. G. J.; Silyakova, A.; Slagstad, D.; Polukhin, A. A.

2017-10-01

The impacts of oceanic CO2 uptake and global warming on the surface ocean environment have received substantial attention, but few studies have focused on shelf bottom water, despite its importance as habitat for benthic organisms and demersal fisheries such as cod. We used a downscaling ocean biogeochemical model to project bottom water acidification and warming on the western Eurasian Arctic shelves. A model hindcast produced 14-18 year acidification trends that were largely consistent with observational estimates at stations in the Iceland and Irminger Seas. Projections under SRES A1B scenario revealed a rapid and spatially variable decline in bottom pH by 0.10-0.20 units over 50 years (2.5%-97.5% quantiles) at depths 50-500 m on the Norwegian, Barents, Kara, and East Greenland shelves. Bottom water undersaturation with respect to aragonite occurred over the entire Kara shelf by 2040 and over most of the Barents and East Greenland shelves by 2070. Shelf acidification was predominantly driven by the accumulation of anthropogenic CO2, and was concurrent with warming of 0.1-2.7°C over 50 years. These combined perturbations will act as significant multistressors on the Barents and Kara shelves. Future studies should aim to improve the resolution of shelf bottom processes in models, and should consider the Kara Sea and Russian shelves as possible bellwethers of shelf acidification.

Seasonal inorganic nitrogen release in alpine lakes on the Colorado western slope

USGS Publications Warehouse

Inyan, B.I.; Williams, M.W.; Tonnessen, K.; Turk, J.T.; Campbell, D.H.

1998-01-01

In the Rocky Mountains, the association of increases in acidic deposition with increased atmospheric loading of sulfate and direct changes in surface water chemistry has been well established. The importance, though, of increased nitrogen (N) deposition in the episodic acidification of alpine lakes and N saturation in alpine ecosystems is only beginning to be documented. In alpine areas of the Colorado Front Range, modest loadings of N in deposition have been associated with leakage of N to surface waters. On the Colorado western slope, however, no leakage of N to surface waters has been reported. A 1995 study that included early season under-ice water samples that were not available in earlier studies showed that there is, in fact, N leakage to surface waters in some western slope basins. Under-ice nitrate (NO3-) concentrations were as high as 10.5 ??q L-1, and only decreased to detection limits in September. Landscape type appears to be important in leakage of N to surface waters, which is associated with basins having steep slopes, thin soils, and large amounts of exposed bedrock. NO3- leakage compounds the existing sensitivity to episodic acidification from low acid neutralizing capacity (ANC), which is less than 40 ??eq L-1 in those basins.

Chemical and biological impacts of ocean acidification along the west coast of North America

NASA Astrophysics Data System (ADS)

Feely, Richard A.; Alin, Simone R.; Carter, Brendan; Bednaršek, Nina; Hales, Burke; Chan, Francis; Hill, Tessa M.; Gaylord, Brian; Sanford, Eric; Byrne, Robert H.; Sabine, Christopher L.; Greeley, Dana; Juranek, Lauren

2016-12-01

The continental shelf region off the west coast of North America is seasonally exposed to water with a low aragonite saturation state by coastal upwelling of CO2-rich waters. To date, the spatial and temporal distribution of anthropogenic CO2 (Canth) within the CO2-rich waters is largely unknown. Here we adapt the multiple linear regression approach to utilize the GO-SHIP Repeat Hydrography data from the northeast Pacific to establish an annually updated relationship between Canth and potential density. This relationship was then used with the NOAA Ocean Acidification Program West Coast Ocean Acidification (WCOA) cruise data sets from 2007, 2011, 2012, and 2013 to determine the spatial variations of Canth in the upwelled water. Our results show large spatial differences in Canth in surface waters along the coast, with the lowest values (37-55 μmol kg-1) in strong upwelling regions off southern Oregon and northern California and higher values (51-63 μmol kg-1) to the north and south of this region. Coastal dissolved inorganic carbon concentrations are also elevated due to a natural remineralized component (Cbio), which represents carbon accumulated through net respiration in the seawater that has not yet degassed to the atmosphere. Average surface Canth is almost twice the surface remineralized component. In contrast, Canth is only about one third and one fifth of the remineralized component at 50 m and 100 m depth, respectively. Uptake of Canth has caused the aragonite saturation horizon to shoal by approximately 30-50 m since the preindustrial period so that undersaturated waters are well within the regions of the continental shelf that affect the shell dissolution of living pteropods. Our data show that the most severe biological impacts occur in the nearshore waters, where corrosive waters are closest to the surface. Since the pre-industrial times, pteropod shell dissolution has, on average, increased approximately 19-26% in both nearshore and offshore waters.

Episodic acidification of 5 rivers in Canada's oil sands during snowmelt: A 25-year record.

PubMed

Alexander, A C; Chambers, P A; Jeffries, D S

2017-12-01

Episodic acidification during snowmelt is a natural phenomenon that can be intensified by acidic deposition from heavy industry. In Canada's oil sands region, acid deposition is estimated to be as much as 5% of the Canadian total and large tracks of northeastern Alberta are considered acid-sensitive because of extensive peatland habitats with poorly weathered soils. To identify the frequency, duration and severity of acidification episodes during snowmelt (the predominant hydrological period for delivery of priority pollutants from atmospheric oil sands emissions to surface waters), a 25-year record (1989 to 2014) of automated water quality data (pH, temperature, conductivity) was assembled for 3 rivers along with a shorter record (2012-2014) for another 2 rivers. Acidic episodes (pH<7, ANC<0) were recorded during 39% of all 83 snowmelt events. The severity (duration x magnitude) of episodic acidification increased exponentially over the study period (r 2 =0.56, P<0.01) and was strongly correlated (P<0.01) with increasing maximum air temperature and weakly correlated with regional land development (P=0.06). Concentrations of aluminum and 11 priority pollutants (Sb, As, Be, Cd, Cr, Cu, Pb, Se, Ag, Tl and Zn) were greatest (P<0.01) during low (<6.5) pH episodes, particularly when coincident with high discharge, such that aluminum and copper concentrations were at times high enough to pose a risk to juvenile rainbow trout (Oncorhynchus mykiss). Although low pH (pH<6.5) was observed during only 8% of 32 acidification episodes, when present, low pH typically lasted 10days. Episodic surface water acidification during snowmelt, and its potential effects on aquatic biota, is therefore an important consideration in the design of long-term monitoring of these typically alkaline (pH=7.72±0.05) rivers. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Fish population losses from Adirondack Lakes: The role of surface water acidity and acidification

NASA Astrophysics Data System (ADS)

Baker, Joan P.; Warren-Hicks, William J.; Gallagher, James; Christensen, Sigurd W.

1993-04-01

Changes over time in the species composition of fish communities in Adirondack lakes were assessed to determine (1) the approximate numbers offish populations that have been lost and (2) the degree to which fish population losses may have resulted from surface water acidification and acidic deposition. Information on the present-day status offish communities was obtained by the Adirondack Lakes Survey Corporation, which surveyed 1469 Adirondack lakes in 1984-1987 (53% of the total ponded waters in the Adirondack ecological zone). Two hundred and ninety-five of these lakes had been surveyed in 1929-1934 during the first statewide biological survey; 720 had been surveyed in one or more years prior to 1970. Sixteen to 19% of the lakes with adequate historical data appeared to have lost one or more fish populations as a result of acidification. Brook trout and acid-sensitive minnow species had experienced the most widespread effects. Populations of brook trout and acid-sensitive minnows had been lost apparently as a result of acidification from 11% and 19%, respectively, of the lakes with confirmed historical occurrence of these taxa. By contrast, fish species that tend to occur primarily in lower elevation and larger lakes, such as largemouth and smallmouth bass and brown trout, have experienced little to no documented adverse effects. Lakes that were judged to have lost fish populations as a result of acidification had significantly lower; pH and, in most cases, also had higher estimated concentrations of inorganic aluminum and occurred at higher elevations than did lakes with the fish species still present. No other lake characteristics were consistently associated with fish population losses attributed to acidification. The exact numbers and proportions of fish populations affected could not be determined because of limitations on the quantity and quality of historical data. Lakes for which we had adequate historical data to assess long-term trends in fish communities were significantly larger and deeper and have higher pH than do Adirondack lakes in general; thus, fish communities adversely affected by acidification and acidic deposition may be underrepresented in this study.

Capturing the global signature of surface ocean acidification during the PETM

NASA Astrophysics Data System (ADS)

Babila, T. L.; Penman, D. E.; Hoenisch, B.; Kelly, D. C.; Bralower, T. J.; Rosenthal, Y.; Zachos, J. C.

2016-12-01

Anthropogenic greenhouse gas emissions over the last century have elevated atmospheric carbon dioxide concentrations while concomitantly acidifying the oceans. Instrumental records are sparse and limited in duration, making it difficult to separate regional from global trends of ocean acidification. Geologically rapid carbon perturbations such as the Paleocene-Eocene Thermal Maximum (PETM, 56 Ma) are arguably the closest paleo analogue to present climate change. Marine ecosystems experienced dynamic changes during the event, and parallel environmental changes, including acidification and warming. Here we present a synthesis of new and published geochemical reconstructions from various oceanographic settings to determine the magnitude and spatial extent of surface ocean acidification. In the deep ocean, acidification is inferred from widespread dissolution of seafloor carbonates, whereas evidence for surface ocean acidification has emerged from planktonic foraminifera boron proxy records (B/Ca and δ11B) (Penman et al. 2014; Babila et al. 2016). B/Ca and δ11B in surface and thermocline planktonic foraminifera suggest a simultaneous decrease at the PETM onset in all pelagic and shelf sites. Salinity, diagenesis and foraminiferal symbiont loss can complicate the interpretation of boron proxy records. Local salinity changes (based on paired Mg/Ca and δ18O) account for a relatively small component of total B/Ca change. The large range in environmental conditions between sites could explain the subtle differences in absolute values exhibited by the records. Shelf sites (ODP 174AX Bass River and Ancora, NJ) reveal similar absolute values and trends compared to pelagic sites (ODP 1209, N. Pacific), precluding a significant preservation bias on the geochemical records. Southern Ocean sites (ODP 689 and 690) are located in colder surface waters and exhibit a similar decrease in B/Ca, suggesting that temperature and symbiont loss are likely not major factors. We conclude that while the mass of released carbon is comparable to anthropogenic emissions, the rate is much slower, resulting in a less severe degree of undersaturation. Furthermore, the consistent latitudinal pattern of acidification suggests that thermal stress rather than acidification contributed to the observed biotic responses.

Declining acidic deposition begins reversal of forest-soil acidification in the northeastern U.S

Treesearch

Gregory B. Lawrence; Paul W. Hazlett; Ivan J. Fernandez; Rock Ouimet; Scott W. Bailey; Walter C. Shortle; Kevin T. Smith; Michael R. Antidormi

2015-01-01

Decreasing trends in acidic deposition levels over the past several decades have led to partial chemical recovery of surface waters. However, depletion of soil Ca from acidic deposition has slowed surface water recovery and led to the impairment of both aquatic and terrestrial ecosystems. Nevertheless, documentation of acidic deposition effects on soils has been...

The effect of acidification on the bioavailability and electrochemical lability of zinc in seawater

PubMed Central

Kim, Ja-Myung; Baars, Oliver

2016-01-01

A poorly studied but potentially important consequence of the CO2-induced acidification of the surface ocean is a possible change in the bioavailability of trace metals, which play a critical role in the productivity and population dynamics of marine ecosystems. We report laboratory and field experiments designed to compare quantitatively the effects of acidification on the bioavailability of Zn, a metal essential to the growth of phytoplankton and on the extent of its complexation by model and natural ligands. We observed a good correspondence between the effects of pH on the rate of Zn uptake by a model diatom and the chemical lability of Zn measured by anodic stripping voltammetry (ASV). In model laboratory systems, the chemical lability and the bioavailability of Zn could either increase or decrease at low pH depending on the mix of complexing ligands. In a sample of coastal surface water, we observed similar increases in the ASV-labile and bioavailable Zn concentrations upon acidification, a result contrary to previous observations. These results, which can likely be generalized to other bioactive trace metals, mutatis mutandis, demonstrate the intricacy of the effects of ocean acidification on the chemistry and the ecology of surface seawater. This article is part of the themed issue ‘Biological and climatic impacts of ocean trace element chemistry’. PMID:29035261

The effect of acidification on the bioavailability and electrochemical lability of zinc in seawater.

PubMed

Kim, Ja-Myung; Baars, Oliver; Morel, François M M

2016-11-28

A poorly studied but potentially important consequence of the CO 2 -induced acidification of the surface ocean is a possible change in the bioavailability of trace metals, which play a critical role in the productivity and population dynamics of marine ecosystems. We report laboratory and field experiments designed to compare quantitatively the effects of acidification on the bioavailability of Zn, a metal essential to the growth of phytoplankton and on the extent of its complexation by model and natural ligands. We observed a good correspondence between the effects of pH on the rate of Zn uptake by a model diatom and the chemical lability of Zn measured by anodic stripping voltammetry (ASV). In model laboratory systems, the chemical lability and the bioavailability of Zn could either increase or decrease at low pH depending on the mix of complexing ligands. In a sample of coastal surface water, we observed similar increases in the ASV-labile and bioavailable Zn concentrations upon acidification, a result contrary to previous observations. These results, which can likely be generalized to other bioactive trace metals, mutatis mutandis , demonstrate the intricacy of the effects of ocean acidification on the chemistry and the ecology of surface seawater.This article is part of the themed issue 'Biological and climatic impacts of ocean trace element chemistry'. © 2016 The Author(s).

USDA Forest Service national protocols for sampling air pollution-sensitive waters

Treesearch

T. J. Sullivan

2012-01-01

The first step in designing a surface water sampling program is identifying one or more problems or questions that require information on water quality. Common water quality problems include nutrient enrichment (from a variety of causes), effects of atmospheric deposition (acidification, eutrophication, toxicity), and effects of major disturbances such as fire or pest...

Effects of mining activities on evolution of water chemistry in coal-bearing aquifers in karst region of Midwestern Guizhou, China: evidences from δ13C of dissolved inorganic carbon and δ34S of sulfate.

PubMed

Li, Qingguang; Wu, Pan; Zha, Xuefang; Li, Xuexian; Wu, Linna; Gu, Shangyi

2018-04-24

The generation of acid mine drainage (AMD) may accelerate watershed erosion and promote the migration of heavy metals, then threaten local ecosystems such as aquatic life and even human health. Previous studies have focused primarily on influence of AMD in surface environment. In order to reveal the acidizing processes in karst high-sulfur coalfield in Southwest China, this study, by contrast, focused on the hydrogeochemical evolution process and acidification mechanism of mine water in Zhijin coalfield, western Guizhou Province. The oxidation of pyrite and other sulfides induced strong acidification of mine water according to the water chemical analysis. As a result, a series of geochemical processes such as dissolution of carbonates and silicates, hydrolysis of metal ions, and degassing of CO 2 complicated water chemical evolution. The dissolution of silicates controlled the chemical composition of mine water, but more carbonates might be dissolved during the acidification of mine water. The sources of sulfate are quite different in water samples collected from the two selected mine. According to sulfur isotope analysis, the dissolution of gypsum is the primary source of sulfate in samples from Hongfa mine, whereas sulfide oxidation contributed a large amount of sulfate to the mine water in Fenghuangshan mine. The dissolution of carbonates should be an important source of DIC in mine water and CO 2 originating from organic mineralization might also have a certain contribution. This study elucidated the groundwater chemical evolution processes in high-sulfur coal-bearing strata and provided a foundation for further study of carbonates erosion and carbon emission during acidification of mine water.

REGIONAL SCALE EVIDENCE FOR IMPROVEMENTS IN SURFACE WATER CHEMISTRY 1990 TO 2001

EPA Science Inventory

The main aim of the international UNECE monitoring program ICP Waters under the Convention of Long-range Transboundary Air Pollution (CLRTAP) is to assess, on a regional basis, the degree and geographical extent of the impact of atmospheric pollution, in particular acidification,...

Deep oceans may acidify faster than anticipated due to global warming

NASA Astrophysics Data System (ADS)

Chen, Chen-Tung Arthur; Lui, Hon-Kit; Hsieh, Chia-Han; Yanagi, Tetsuo; Kosugi, Naohiro; Ishii, Masao; Gong, Gwo-Ching

2017-12-01

Oceans worldwide are undergoing acidification due to the penetration of anthropogenic CO2 from the atmosphere1-4. The rate of acidification generally diminishes with increasing depth. Yet, slowing down of the thermohaline circulation due to global warming could reduce the pH in the deep oceans, as more organic material would decompose with a longer residence time. To elucidate this process, a time-series study at a climatically sensitive region with sufficient duration and resolution is needed. Here we show that deep waters in the Sea of Japan are undergoing reduced ventilation, reducing the pH of seawater. As a result, the acidification rate near the bottom of the Sea of Japan is 27% higher than the rate at the surface, which is the same as that predicted assuming an air-sea CO2 equilibrium. This reduced ventilation may be due to global warming and, as an oceanic microcosm with its own deep- and bottom-water formations, the Sea of Japan provides an insight into how future warming might alter the deep-ocean acidification.

Effects of acidic deposition on in-lake phosphorus availability: a lesson from lakes recovering from acidification.

PubMed

Kopáček, Jiří; Hejzlar, Josef; Kaňa, Jiří; Norton, Stephen A; Stuchlík, Evžen

2015-03-03

Lake water concentrations of phosphorus (P) recently increased in some mountain areas due to elevated atmospheric input of P rich dust. We show that increasing P concentrations also occur during stable atmospheric P inputs in central European alpine lakes recovering from atmospheric acidification. The elevated P availability in the lakes results from (1) increasing terrestrial export of P accompanying elevated leaching of dissolved organic carbon and decreasing phosphate-adsorption ability of soils due to their increasing pH, and (2) decreasing in-lake P immobilization by aluminum (Al) hydroxide due to decreasing leaching of ionic Al from the recovering soils. The P availability in the recovering lakes is modified by the extent of soil acidification, soil composition, and proportion of till and meadow soils in the catchment. These mechanisms explain several conflicting observations of the acid rain effects on surface water P concentrations.

Hydrogeologic controls of surface-water chemistry in the Adirondack region of New York State

USGS Publications Warehouse

Peters, N.E.; Driscoll, C.T.

1987-01-01

Relationships between surface-water discharge, water chemistry, and watershed geology were investigated to evaluate factors affecting the sensitivity of drainage waters in the Adirondack region of New York to acidification by atmospheric deposition. Instantaneous discharge per unit area was derived from relationships between flow and staff-gage readings at 10 drainage basins throughout the region. The average chemical composition of the waters was assessed from monthly samples collected from July 1982 through July 1984. The ratio of flow at the 50-percent exceedence level to the flow at the 95-percent exceedence level of flow duration was negatively correlated with mean values of alkalinity or acid-neutralizing capacity (ANC), sum of basic cations (SBC), and dissolved silica, for basins containing predominantly aluminosilicate minerals and little or no carbonate-bearing minerals. Low ratios are indicative of systems in which flow is predominately derived from surface- and ground-water storage, whereas high ratios are characteristic of watersheds with variable flow that is largely derived from surface runoff. In an evaluation of two representative surface-water sites, concentrations of ANC, SBC, and dissolved silica, derived primarily from soil mineral weathering reactions. decreased with increasing flow. Furthermore, the ANC was highest at low flow when the percentage of streamflow derived from ground water was maximum. As flow increased, the ANC decreased because the contribution of dilute surface runoff and lateral flow through the shallow acidic soil horizons to total flow increased. Basins having relatively high ground-water contributions to total flow, in general, have large deposits of thick till or stratified drift. A major factor controlling the sensitivity of these streams and lakes to acidification is the relative contribution of ground water to total discharge. ?? 1987 Martinus Nijhoff/Dr W. Junk Publishers.

Persistent episodic acidification of streams linked to acid rain effects on soil

USGS Publications Warehouse

Lawrence, G.B.

2002-01-01

Episodic acidification of streams, identified in the late 1980s as one of the most significant environmental problems caused by acidic deposition, had not been evaluated since the early 1990s despite decreasing levels of acidic deposition over the past decade. This analysis indicates that episodic acidification of streams in upland regions in the northeastern United States persists, and is likely to be much more widespread than chronic acidification. Depletion of exchangeable Ca in the mineral soil has decreased the neutralization capacity of soils and increased the role of the surface organic horizon in the neutralization of acidic soil water during episodes. Increased accumulation of N and S in the forest floor from decades of acidic deposition will delay the recovery of soil base status, and therefore, the elimination of acidic episodes, which is anticipated from decreasing emissions.

Decreased abundance of crustose coralline algae due to ocean acidification

USGS Publications Warehouse

Kuffner, Ilsa B.; Andersson, Andreas J; Jokiel, Paul L.; Rodgers, Ku'ulei S.; Mackenzie, Fred T.

2008-01-01

Owing to anthropogenic emissions, atmospheric concentrations of carbon dioxide could almost double between 2006 and 2100 according to business-as-usual carbon dioxide emission scenarios1. Because the ocean absorbs carbon dioxide from the atmosphere2, 3, 4, increasing atmospheric carbon dioxide concentrations will lead to increasing dissolved inorganic carbon and carbon dioxide in surface ocean waters, and hence acidification and lower carbonate saturation states2, 5. As a consequence, it has been suggested that marine calcifying organisms, for example corals, coralline algae, molluscs and foraminifera, will have difficulties producing their skeletons and shells at current rates6, 7, with potentially severe implications for marine ecosystems, including coral reefs6, 8, 9, 10, 11. Here we report a seven-week experiment exploring the effects of ocean acidification on crustose coralline algae, a cosmopolitan group of calcifying algae that is ecologically important in most shallow-water habitats12, 13, 14. Six outdoor mesocosms were continuously supplied with sea water from the adjacent reef and manipulated to simulate conditions of either ambient or elevated seawater carbon dioxide concentrations. The recruitment rate and growth of crustose coralline algae were severely inhibited in the elevated carbon dioxide mesocosms. Our findings suggest that ocean acidification due to human activities could cause significant change to benthic community structure in shallow-warm-water carbonate ecosystems.

TRENDS IN SURFACE WATER ACIDIFICATION IN EUROPE AND NORTH AMERICA (1989-1998)

EPA Science Inventory

During the last 20 years, emission reductions in Europe and North America have resulted in decreased atmospheric Sulfur-deposition of up to 50%, while Nitrogen-deposition has stayed almost constant. Data from 98 ICP Waters sites were tested for trends in concentrations of major c...

Major element concentrations in six Alaskan arctic rivers from melt to freeze-up

NASA Astrophysics Data System (ADS)

Douglas, T. A.; Barker, A.; Jacobson, A. D.; McClelland, J. W.; Khosh, M. S.; Lehn, G. O.

2010-12-01

It is increasingly evident that permafrost in the Arctic is responding to climate warming. An expected response to this warming is permafrost degradation and the downward migration of the seasonally thawed (active) layer into previously frozen material. This could allow weathering of previously frozen soils and influence surface water biogeochemistry in Arctic rivers. The weathering signal would most likely be evident in surface waters during summer and early fall base flow when the active layer is at its deepest extent. Studies collecting water samples from spring through late fall could capture these flows. Fieldwork in remote regions often requires long storage times for samples prior to analysis. One aspect of our study was to investigate whether waters collected for major element analyses should be preserved by acidification. We collected up to 60 surface water samples from each of six rivers between April and October, 2009. Two rivers were underlain by organic rich permafrost, two of the rivers drained mountainous bedrock, and two rivers were underlain by a combination of both bedrock and organic rich permafrost. We collected duplicate samples from each river. Samples were filtered in the field to less than 0.45 microns and collected into high density polyethylene bottles. Waters were stored for six months prior to analysis. One set of samples was analyzed without acidification while the second set was acidified with nitric acid to a pH of 2 after 6 months of storage. Concentrations of sodium, potassium, magnesium, calcium, ammonium, fluoride, chloride, nitrate, sulfate and phosphate were measured from all samples by ion chromatography. Sulfate, calcium, magnesium, sodium and potassium concentrations increase steadily through the summer from the end of spring melt into early fall. In all six rivers the potassium concentrations are unaffected by acidification. In the two streams underlain by organic rich permafrost and in one of the bedrock streams the calcium, magnesium, and sodium values are similar for both the acidified and unacidified samples. In the other rivers, however, the calcium, magnesium and sodium concentrations yield complex behavior. From spring melt into early summer the cation values are identical in the acidified and unacidified samples. However, in late summer and early fall calcium, magnesium, and sodium concentrations are roughly ten percent higher in the acidified samples than in the unacidified ones. Our results suggest an enhanced mineral weathering signal in the watersheds in the late summer which is evidenced by steadily increasing sulfate and cation concentrations throughout the summer. Potassium does not appear to be affected by acidification. Some cation species respond to acidification, especially in waters representing baseflow. However, the cause(s) for the higher values in some acidified samples is unknown.

An experimental study on ferrous iron photo-oxidation: Effect of the solar spectrum on the surface for acidification of surface water in the early Hesperian Mars

NASA Astrophysics Data System (ADS)

Tabata, H.; Sekine, Y.; Kanzaki, Y.; Sugita, S.; Murakami, T.

2017-12-01

Geochemical evidence obatined by Mars Opportunity rover suggests that the pH of Martian surface water shifted to highly acidic, i.e., pH 2-4, in the early Hesperian (e.g., Tosca et al., 2005). Hurowitz et al. (2010) proposed that solar UV light may have promoted the acidification through photo-oxidation of ferrous iron dissolved in upwelling groundwater on early Mars. However, the trigger for the acidification in the early Hesperian remains unclear. The photo-oxidation of Fe2+ occurs under acidic conditions, i.e., pH < 3 (Jortner et al., 1962); however, the pH of upwelling groundwater would be neutral to alkaline (Zolotov et al., 2016). At neutral to alkaline pH, FeOH+ can exist together with Fe2+ in a solution. While both Fe2+ and FeOH+ are photo-oxidized only by UV light (< 300 nm), FeOH+ can also be photo-oxidized by long UV/visible light (300-400 nm). Thus, the efficiency of acidification through photo-oxidation on early Mars should have depended on the solar spectrum on the surface at that time which is determined by the atmospheric composition. To investigate the effect of UV spectrum on the acidification, we conducted two types of laboratory experiments: One used a Xe lamp as the light source for photo-oxidation of ferrous iron to irradiate light with continuous spectrum from 250 to 400 nm, and the other used the Xe lamp with an optical filter that cuts off UV light shorter than 300 nm. The pH value of the starting solution was around 7. Upon the UV irradiation covering full wavelength range (250-400 nm), the pH value of the solution decreases down to less than 4, consistent with the proposed pH of the Hesperian acidic water on Meridiani Planum (Tosca et al., 2005). This occurs because Fe2+ is stable at pH < 5, and because Fe2+ can be continuously photo-oxidized in the acidic solution by UV light in 250-300 nm. When the UV irradiation covering 300-400 nm, the pH value of the solution also decreases to pH 5 immediately after the UV irradiation. However, it does not decrease less than pH 5 and reaches a steady state. This is the case because FeOH+ is converted into Fe2+ at low pH, which prevents further photo-oxidation by light in 300-400 nm. These results suggest that a change in the atmospheric composition and consequent reaching of UV light in the wavelength < 300 nm may have played a key role for triggering the acidification in the early Hesperian.

Impact of anthropogenic atmospheric nitrogen and sulfur deposition on ocean acidification and the inorganic carbon system.

PubMed

Doney, Scott C; Mahowald, Natalie; Lima, Ivan; Feely, Richard A; Mackenzie, Fred T; Lamarque, Jean-Francois; Rasch, Phil J

2007-09-11

Fossil fuel combustion and agriculture result in atmospheric deposition of 0.8 Tmol/yr reactive sulfur and 2.7 Tmol/yr nitrogen to the coastal and open ocean near major source regions in North America, Europe, and South and East Asia. Atmospheric inputs of dissociation products of strong acids (HNO(3) and H2SO(4)) and bases (NH(3)) alter surface seawater alkalinity, pH, and inorganic carbon storage. We quantify the biogeochemical impacts by using atmosphere and ocean models. The direct acid/base flux to the ocean is predominately acidic (reducing total alkalinity) in the temperate Northern Hemisphere and alkaline in the tropics because of ammonia inputs. However, because most of the excess ammonia is nitrified to nitrate (NO(3)(-)) in the upper ocean, the effective net atmospheric input is acidic almost everywhere. The decrease in surface alkalinity drives a net air-sea efflux of CO(2), reducing surface dissolved inorganic carbon (DIC); the alkalinity and DIC changes mostly offset each other, and the decline in surface pH is small. Additional impacts arise from nitrogen fertilization, leading to elevated primary production and biological DIC drawdown that reverses in some places the sign of the surface pH and air-sea CO(2) flux perturbations. On a global scale, the alterations in surface water chemistry from anthropogenic nitrogen and sulfur deposition are a few percent of the acidification and DIC increases due to the oceanic uptake of anthropogenic CO(2). However, the impacts are more substantial in coastal waters, where the ecosystem responses to ocean acidification could have the most severe implications for mankind.

Poorly cemented coral reefs of the eastern tropical Pacific: possible insights into reef development in a high-CO2 world.

PubMed

Manzello, Derek P; Kleypas, Joan A; Budd, David A; Eakin, C Mark; Glynn, Peter W; Langdon, Chris

2008-07-29

Ocean acidification describes the progressive, global reduction in seawater pH that is currently underway because of the accelerating oceanic uptake of atmospheric CO(2). Acidification is expected to reduce coral reef calcification and increase reef dissolution. Inorganic cementation in reefs describes the precipitation of CaCO(3) that acts to bind framework components and occlude porosity. Little is known about the effects of ocean acidification on reef cementation and whether changes in cementation rates will affect reef resistance to erosion. Coral reefs of the eastern tropical Pacific (ETP) are poorly developed and subject to rapid bioerosion. Upwelling processes mix cool, subthermocline waters with elevated pCO(2) (the partial pressure of CO(2)) and nutrients into the surface layers throughout the ETP. Concerns about ocean acidification have led to the suggestion that this region of naturally low pH waters may serve as a model of coral reef development in a high-CO(2) world. We analyzed seawater chemistry and reef framework samples from multiple reef sites in the ETP and found that a low carbonate saturation state (Omega) and trace abundances of cement are characteristic of these reefs. These low cement abundances may be a factor in the high bioerosion rates previously reported for ETP reefs, although elevated nutrients in upwelled waters may also be limiting cementation and/or stimulating bioerosion. ETP reefs represent a real-world example of coral reef growth in low-Omega waters that provide insights into how the biological-geological interface of coral reef ecosystems will change in a high-CO(2) world.

A Possible Late Paleocene-Early Eocene Ocean Acidification Event Recoded in the Adriatic Carbonate Platform

NASA Astrophysics Data System (ADS)

Weiss, A.; Martindale, R. C.; Kosir, A.; Oefinger, J.

2017-12-01

The Paleocene-Eocene Thermal Maximum (PETM) event ( 56.3 Ma) was a period of massive carbon release into the Earth system, resulting in significant shifts in ocean chemistry. It has been proposed that ocean acidification - a decrease in the pH and carbonate saturation state of the water as a result of dissolved carbon dioxide in sea water - occurred in both the shallow and deep marine realms. Ocean acidification would have had a devastating impact on the benthic ecosystem, and has been proposed as the cause of decreased carbonate deposition in marine sections and coral reef collapse during the late Paleocene. To date, however, the only physical evidence of Paleocene-Eocene ocean acidification has been shown for offshore sites (i.e., a shallow carbonate compensation depth), but isotope analysis (i.e. B, I/Ca) suggests that acidification occurred in the shallow shelves as well. Several sites in the Kras region of Slovenia, has been found to contain apparent erosion surfaces coeval with the Paleocene-Eocene Boundary. We have investigated these potentially acidified horizons using petrography, stable carbon isotopes, cathodoluminescence, and elemental mapping. These datasets will inform whether the horizons formed by seafloor dissolution in an acidified ocean, or are due to subaerial exposure, or burial diagenesis (i.e. stylotization). Physical erosion and diagenesis can easily be ruled out based on field relationships and petrography, but the other potential causes must be analyzed more critically.

WATERSHED MANIPULATION PROJECT: QUALITY ASSURANCE IMPLEMENTATION PLAN FOR 1986-1989

EPA Science Inventory

The Watershed Manipulation Project (WMP) was implemented by EPA to: identify and quantify the relative importance of various processes in controlling surface water acidification with particular emphasis on the role of sulfate adsorption and base cation supply in the long-term wat...

Aragonite undersaturation in the Arctic Ocean: effects of ocean acidification and sea ice melt.

PubMed

Yamamoto-Kawai, Michiyo; McLaughlin, Fiona A; Carmack, Eddy C; Nishino, Shigeto; Shimada, Koji

2009-11-20

The increase in anthropogenic carbon dioxide emissions and attendant increase in ocean acidification and sea ice melt act together to decrease the saturation state of calcium carbonate in the Canada Basin of the Arctic Ocean. In 2008, surface waters were undersaturated with respect to aragonite, a relatively soluble form of calcium carbonate found in plankton and invertebrates. Undersaturation was found to be a direct consequence of the recent extensive melting of sea ice in the Canada Basin. In addition, the retreat of the ice edge well past the shelf-break has produced conditions favorable to enhanced upwelling of subsurface, aragonite-undersaturated water onto the Arctic continental shelf. Undersaturation will affect both planktonic and benthic calcifying biota and therefore the composition of the Arctic ecosystem.

Decreasing DOC trends in soil solution along the hillslopes at two IM sites in southern Sweden--geochemical modeling of organic matter solubility during acidification recovery.

PubMed

Löfgren, Stefan; Gustafsson, Jon Petter; Bringmark, Lage

2010-12-01

Numerous studies report increased concentrations of dissolved organic carbon (DOC) during the last two decades in boreal lakes and streams in Europe and North America. Recently, a hypothesis was presented on how various spatial and temporal factors affect the DOC dynamics. It was concluded that declining sulphur deposition and thereby increased DOC solubility, is the most important driver for the long-term DOC concentration trends in surface waters. If this recovery hypothesis is correct, the DOC levels should increase both in the soil solution as well as in the surrounding surface waters as soil pH rises and the ionic strength declines due to the reduced input of SO(4)(2-) ions. In this project a geochemical model was set up to calculate the net humic charge and DOC solubility trends in soils during the period 1996-2007 at two integrated monitoring sites in southern Sweden, showing clear signs of acidification recovery. The Stockholm Humic Model was used to investigate whether the observed DOC solubility is related to the humic charge and to examine how pH and ionic strength influence it. Soil water data from recharge and discharge areas, covering both podzols and riparian soils, were used. The model exercise showed that the increased net charge following the pH increase was in many cases counteracted by a decreased ionic strength, which acted to decrease the net charge and hence the DOC solubility. Thus, the recovery from acidification does not necessarily have to generate increasing DOC trends in soil solution. Depending on changes in pH, ionic strength and soil Al pools, the trends might be positive, negative or indifferent. Due to the high hydraulic connectivity with the streams, the explanations to the DOC trends in surface waters should be searched for in discharge areas and peat lands. Copyright © 2010 Elsevier B.V. All rights reserved.

Linking water and carbon cycles through salinity observed from space

NASA Astrophysics Data System (ADS)

Xie, X.; Liu, W. T.

2017-12-01

The association of ocean surface salinity in global hydrological cycle and climate change has been traditionally studied through the examination of its tendency and advection as manifestation of ocean's heat and water fluxes with the atmosphere. The variability of surface heat and water fluxes are linked to top of atmosphere radiation, whose imbalance is the main cause of global warming. Besides the link of salinity to greenhouse warming through water balance, this study will focus on the effect of changing salinity on carbon dioxide flux between the ocean and the atmosphere. We have built statistical models to estimate the partial pressure of carbon dioxide (pCO2) and ocean acidification (in terms of total alkalinity and pH) using spacebased data. PCO2 is a critical parameter governing ocean as source and sink of the accumulated greenhouse gas in the atmosphere. The exchange also causes ocean acidification, which is detrimental to marine lives and ecology. Before we had sufficient spacebased salinity measurements coincident with in situ pCO2 measurement, we trained our statistical models to use satellite sea surface temperature and chlorophyll, with one model using salinity climatology and the other without. We found significant differences between the two models in regions of strong water input through river discharge and surface water flux. The pCO2 output follows the seasonal salinity advection of the Amazon outflow. The seasonal salinity advection between Bay of Bengal and Arabian Sea are followed by change of pCO2 and total alkalinity. At shorter time scales, the signatures of rain associated with intraseasonal organized convection of summer monsoon can be detected. We have observed distribution agreement of among pCO2, surface salinity, and surface water flux for variation from a few days to a few years under the Pacific ITCZ; the agreement varies slightly with season and longitudes and the reason is under study.

Effects of Ocean Acidification on the Brown Alga Padina pavonica: Decalcification Due to Acute and Chronic Events

PubMed Central

Gil-Díaz, Teba; Haroun, Ricardo; Tuya, Fernando; Betancor, Séfora; Viera-Rodríguez, María A.

2014-01-01

Since the industrial revolution, anthropogenic CO2 emissions have caused ocean acidification, which particularly affects calcified organisms. Given the fan-like calcified fronds of the brown alga Padina pavonica, we evaluated the acute (short-term) effects of a sudden pH drop due to a submarine volcanic eruption (October 2011–early March 2012) affecting offshore waters around El Hierro Island (Canary Islands, Spain). We further studied the chronic (long-term) effects of the continuous decrease in pH in the last decades around the Canarian waters. In both the observational and retrospective studies (using herbarium collections of P. pavonica thalli from the overall Canarian Archipelago), the percent of surface calcium carbonate coverage of P. pavonica thalli were contrasted with oceanographic data collected either in situ (volcanic eruption event) or from the ESTOC marine observatory data series (herbarium study). Results showed that this calcified alga is sensitive to acute and chronic environmental pH changes. In both cases, pH changes predicted surface thallus calcification, including a progressive decalcification over the last three decades. This result concurs with previous studies where calcareous organisms decalcify under more acidic conditions. Hence, Padina pavonica can be implemented as a bio-indicator of ocean acidification (at short and long time scales) for monitoring purposes over wide geographic ranges, as this macroalga is affected and thrives (unlike strict calcifiers) under more acidic conditions. PMID:25268231

Americium behaviour in plastic vessels.

PubMed

Legarda, F; Herranz, M; Idoeta, R; Abelairas, A

2010-01-01

The adsorption of (241)Am dissolved in water in different plastic storage vessels was determined. Three different plastics were investigated with natural and distilled waters and the retention of (241)Am by these plastics was studied. The same was done by varying vessel agitation time, vessel agitation speed, surface/volume ratio of water in the vessels and water pH. Adsorptions were measured to be between 0% and 70%. The adsorption of (241)Am is minimized with no water agitation, with PET or PVC plastics, and by water acidification. Copyright 2009 Elsevier Ltd. All rights reserved.

The features of element concentration in natural waters of the Kola North in conditions of environmental contamination

NASA Astrophysics Data System (ADS)

Bazova, Mariya; Moiseenko, Tatyana

2016-04-01

The intensive use of fossil fuels and industrial development in last century led to the formation of acid rain and water acidification. The problem of water acidification greatly was denoted in the middle of last century in North America and in Europe as a result of air emissions of acid gases, primarily sulfur dioxide. The process of water acidification due to the interaction of two factors: 1) the high deposition of acidifying substances, taking into account the duration of exposure; 2) the sensitivity of the natural catchment area of geological, landscape, geographic and climatic characteristics (Moiseenko, 2005). The effects of acid rains on metal migration and cycling were discussed in a number of previous studies (Jeffries, 1997; Moiseenko, 1999; Manio, 2001; Moiseenko, Gashkina, 2007). The distribution of elements in water lakes has been mixed and due to the change of geochemical cycles of elements occurring in the catchment area and in water. On the Kola Peninsula as a result of long-term operation of the copper-nickel smelter was the anthropogenic acidification and water pollution metals. Increased contents of elements due to the combined effect of three factors: 1) landscape-geochemical characteristics of watersheds; 2) dispersion with flue emissions; 3) leaching elements and bonding of metals with organic matter, especially in forested watersheds and wetlands. This region is subject to long-term effects of mining and smelting industries, and therefore difficult to find of water bodies, which can serve as a background lakes. It is proved that manmade acid rain lead to leach into the water of a large group of elements entering the water as a result of man-made streams, as well as the elements that consist of the rocks forming the watersheds. In order to identify the relationships between the components of the elemental composition of the water in the lake was made a factor analysis using a computer program «STATISTICA 10". Factor analysis revealed the main processes that determine the conditions of residence and the behavior of elements in the water lakes. It was found that a key role in the formation of natural waters has the cumulative effect of landscape-geochemical conditions and anthropogenic impact. A great contribution, as shown by factorial analysis, make humic acid, which enhance the migratory activity elements. Jeffries D.S. (1997) Canadian acid rain assessment. Toronto. 3, 113 p. Moiseenko T.I. (1999) The fate of metals in Arctic surface waters: Method for defining critical levels Sci. Total Environ. 236, 19-39. Mannio J. (2001) Responces of headwater lakes to air pollution changes in Finland: Acad. Diss. Helsinki: Univ. Helsinki, 226 p. Moiseenko T.I., Gashkina N.A. (2007) Distribution of trace elements in surface waters and feature of their migration // Water resources. V. 34, № 4. P. 454-468. Moiseenko T.I. (2005) Water acidification and behavior of trace elements // Geochemistry. V.10. P.1120-1127. This work has done under the grant of the Russian Foundation of Fundamental Research (ofi_m) №15-29-06948 «The features formation of water quality conditions in Arctic regions of development mineral resources: algorithms settlements of permissible impact»

Evaluation of a regional air-quality model with bidirectional NH3 exchange coupled to an agroecosystem modelecosystem model

EPA Science Inventory

Atmospheric ammonia (NH₃) is the primary atmospheric base and an important precursor for inorganic particulate matter and when deposited NH₃ contributes to surface water eutrophication, soil acidification and decline in species biodiversity. Flux measurement...

SEASONAL AND LONG-TERM TEMPORAL PATTERNS IN THE CHEMISTRY OF ADIRONDACK LAKES

EPA Science Inventory

There is considerable interest in the recovery of surface waters from acidification by acidic deposition. he Adirondack Long-Term Monitoring (ALTM) program was established in 1982 to evaluate changes in the chemistry of 17 Adirondack lakes. he objectives of this paper are to: 1) ...

IMPORTANCE OF GROUNDWATER SULFATE TO ACIDIFICATION IN THE GOOSE RIVER WATERSHED, MAINE

EPA Science Inventory

The role of groundwater sulfate discharge to ponds and streams within the Goose River basin (33.3 km²) is examined. While airborne sulfate disposition has declined, acidity in surface waters locally remains elevated. Monthly SO^2-₄ analyses (1999-2...

Study of novel mechano-chemical activation process of red mud to optimize nitrate removal from water.

PubMed

Alighardashi, A; Gharibi, H R; Raygan, Sh; Akbarzadeh, A

2016-01-01

Red mud (RM) is the industrial waste of alumina production and causes serious environmental risks. In this paper, a novel activation procedure for RM (mechano-chemical processing) is proposed in order to improve the nitrate adsorption from water. High-energy milling and acidification were selected as mechanical and chemical activation methods, respectively. Synthesized samples of adsorbent were produced considering two parameters of activation: acid concentrations and acidification time in two selected milling times. Optimization of the activation process was based on nitrate removal from a stock solution. Experimental data were analyzed with two-way analysis of variance and Kruskal-Wallis methods to verify and discover the accuracy and probable errors. Best conditions (acceptable removal percentage > 75) were 17.6% w/w for acid concentrate and 19.9 minutes for acidification time in 8 hours for milling time. A direct relationship between increase in nitrate removal and increasing the acid concentration and acidification time was observed. The adsorption isotherms were studied and compared with other nitrate adsorbents. Characterization tests (X-ray fluorescence, X-ray diffraction, Fourier transform infrared spectrophotometry, dynamic light scattering, surface area analysis and scanning electron microscopy) were conducted for both raw and activated adsorbents. Results showed noticeable superiority in characteristics after activation: higher specific area and porosity, lower particle size and lower agglomeration in structure.

River catchment responses to anthropogenic acidification in relationship with sewage effluent: An ecotoxicology screening application.

PubMed

Oberholster, P J; Botha, A-M; Hill, L; Strydom, W F

2017-12-01

Rising environmental pressures on water resources and resource quality associated with urbanisation, industrialisation, mining and agriculture are a global concern. In the current study the upper Olifants River catchment as case study was used, to show that acid mine drainage (AMD) and acid precipitation were the two most important drivers of possible acidification during a four-year study period. Over the study period 59% of the precipitation sampled was classified as acidic with a pH value below 5.6. Traces of acidification in the river system using aquatic organisms at different trophic levels were only evident in areas of AMD point sources. Data gathered from the ecotoxicology screening tools, revealed that discharge of untreated and partially treated domestic sewage from municipal sewage treatment works and informal housing partially mitigate any traces of acidification by AMD and acid precipitation in the main stem of the upper Olifants River. The outcome of the study using phytoplankton and macroinvertebrates as indicator organisms revealed that the high loads of sewage effluent might have played a major role in the neutralization of acidic surface water conditions caused by AMD and acid precipitation. Although previous multi-stage and microcosm studies confirmed the decrease in acidity and metals concentrations by municipal wastewater, the current study is the first to provide supportive evidence of this co-attenuation on catchment scale. These findings are important for integrated water resource management on catchment level, especially in river systems with a complex mixture of pollutants. Copyright © 2017 Elsevier Ltd. All rights reserved.

Vertical and horizontal distribution of Desmophyllum dianthus in Comau Fjord, Chile: a cold-water coral thriving at low pH

PubMed Central

Richter, Claudio

2013-01-01

Cold-water corals provide an important habitat for a rich fauna along the continental margins and slopes. Although these azooxanthellate corals are considered particularly sensitive to ocean acidification, their responses to natural variations in pH and aragonite saturation are largely unknown due to the difficulty of studying their ecology in deep waters. Previous SCUBA investigations have shown an exceptionally shallow population of the cold-water coral Desmophyllum dianthus in near-surface waters of Comau Fjord, a stratified 480 m deep basin in northern Chilean Patagonia with suboxic deep waters. Here, we use a remotely operated vehicle to quantitatively investigate the distribution of D. dianthus and its physico-chemical drivers in so far uncharted naturally acidified waters. Remarkably, D. dianthus was ubiquitous throughout the fjord, but particularly abundant between 20 and 280 m depth in a pH range of 8.4 to 7.4. The persistence of individuals in aragonite-undersaturated waters suggests that present-day D. dianthus in Comau Fjord may show pre-acclimation or pre-adaptation to conditions of ocean acidification predicted to reach over 70% of the known deep-sea coral locations by the end of the century. PMID:24255810

Vertical and horizontal distribution of Desmophyllum dianthus in Comau Fjord, Chile: a cold-water coral thriving at low pH.

PubMed

Fillinger, Laura; Richter, Claudio

2013-01-01

Cold-water corals provide an important habitat for a rich fauna along the continental margins and slopes. Although these azooxanthellate corals are considered particularly sensitive to ocean acidification, their responses to natural variations in pH and aragonite saturation are largely unknown due to the difficulty of studying their ecology in deep waters. Previous SCUBA investigations have shown an exceptionally shallow population of the cold-water coral Desmophyllum dianthus in near-surface waters of Comau Fjord, a stratified 480 m deep basin in northern Chilean Patagonia with suboxic deep waters. Here, we use a remotely operated vehicle to quantitatively investigate the distribution of D. dianthus and its physico-chemical drivers in so far uncharted naturally acidified waters. Remarkably, D. dianthus was ubiquitous throughout the fjord, but particularly abundant between 20 and 280 m depth in a pH range of 8.4 to 7.4. The persistence of individuals in aragonite-undersaturated waters suggests that present-day D. dianthus in Comau Fjord may show pre-acclimation or pre-adaptation to conditions of ocean acidification predicted to reach over 70% of the known deep-sea coral locations by the end of the century.

Ammonium and inorganic species in fractionated suspended particulate matters from broiler house with rice hull beddings

USDA-ARS?s Scientific Manuscript database

Ammonia emission and subsequent deposition can be a major source of pollution, causing nitrogen enrichment, acidification of soils and surface waters, and aerosol formation. In the poultry house, ammonia emissions can also adversely affect the health, performance, and welfare of both animals and hu...

The effect of aged litter materials on polyatomic ion concentrations in fractionated suspended particulate matter from broiler house

USDA-ARS?s Scientific Manuscript database

Inorganic emissions from livestock production and subsequent deposition of these ions can be a major source of pollution, causing nitrogen enrichment, eutrophication, acidification of soils and surface waters, and aerosol formation. In the poultry house, ammonia and hydrogen sulfide emissions can a...

Decreased atmospheric sulfur deposition across the southeastern U.S.: When will watersheds release stored sulfate?

Treesearch

Karen C. Rice; Todd M. Scanlon; Jason A. Lynch; Bernard J. Cosby

2014-01-01

Emissions of sulfur dioxide (SO2) to the atmosphere lead to atmospheric deposition of sulfate (SO42-), which is the dominant strong acid anion causing acidification of surface waters and soils in the eastern United States. Since passage of the Clean Air Act and its Amendments, atmospheric deposition...

Recent 121-year variability of western boundary upwelling in the northern South China Sea

NASA Astrophysics Data System (ADS)

Liu, Yi; Peng, Zicheng; Shen, Chuan-Chou; Zhou, Renjun; Song, Shaohua; Shi, Zhengguo; Chen, Tegu; Wei, Gangjian; Delong, Kristine L.

2013-06-01

upwelling is typically related to the eastern boundary upwelling system, whereas the powerful southwest Asian summer monsoon can also generate significant cold, nutrient-rich deep water in western coastal zones. Here we present a sea surface temperature record (A.D. 1876-1996) derived from coral Porites Sr/Ca for an upwelling zone in the northern South China Sea. The upwelling-induced sea surface temperature anomaly record reveals prominent multidecadal variability driven by Asian summer monsoon dynamics with an abrupt transition from warmer to colder conditions in 1930, and a return to warmer conditions after 1960. Previous studies suggest the expected increase in atmospheric CO2 for the coming decades may result in intensification in the eastern boundary upwelling system, which could enhance upwelling of CO2-rich deep water thus exacerbating the impact of acidification in these productive zones. In contrast, the weakening trend since 1961 in the upwelling time series from the northern South China Sea suggests moderate regional ocean acidification from upwelling thus a stress relief for marine life in this region.

Ocean acidification in the Meso- vs. Cenozoic: lessons from modeling about the geological expression of paleo-ocean acidification

NASA Astrophysics Data System (ADS)

Greene, S. E.; Ridgwell, A.; Kirtland Turner, S.

2015-12-01

Rapid climatic and biotic events putatively associated with ocean acidification are scattered throughout the Meso-Cenozoic. Many of these rapid perturbations, variably referred to as hyperthermals (Paleogene) and oceanic anoxic events or mass extinction events (Mesozoic), share a number of characteristic features, including some combination of negative carbon isotopic excursion, global warming, and a rise in atmospheric CO2 concentration. Comparisons between ocean acidification events over the last ~250 Ma are, however, problematic because the types of marine geological archives and carbon reservoirs that can be interrogated are fundamentally different for early Mesozoic vs. late Mesozoic-Cenozoic events. Many Mesozoic events are known primarily or exclusively from geological outcrops of relatively shallow water deposits, whereas the more recent Paleogene hyperthermal events have been chiefly identified from deep sea records. In addition, these earlier events are superimposed on an ocean with a fundamentally different carbonate buffering capacity, as calcifying plankton (which created the deep-sea carbonate sink) originate in the mid-Mesozoic. Here, we use both Earth system modeling and reaction transport sediment modeling to explore the ways in which comparable ocean acidification-inducing climate perturbations might manifest in the Mesozoic vs. the Cenozoic geological record. We examine the role of the deep-sea carbonate sink in the expression of ocean acidification, as well as the spatial heterogeneity of surface ocean pH and carbonate saturation state. These results critically inform interpretations of ocean acidification prior to the mid-Mesozoic advent of calcifying plankton and expectations about the recording of these events in geological outcrop.

Ocean Fertilization and Ocean Acidification

NASA Astrophysics Data System (ADS)

Cao, L.; Caldeira, K.

2008-12-01

It has been suggested that ocean fertilization could help diminish ocean acidification. Here, we quantitatively evaluate this suggestion. Ocean fertilization is one of several ocean methods proposed to mitigate atmospheric CO2 concentrations. The basic idea of this method is to enhance the biological uptake of atmospheric CO2 by stimulating net phytoplankton growth through the addition of iron to the surface ocean. Concern has been expressed that ocean fertilization may not be very effective at reducing atmospheric CO2 concentrations and may produce unintended environmental consequences. The rationale for thinking that ocean fertilization might help diminish ocean acidification is that dissolved inorganic carbon concentrations in the near-surface equilibrate with the atmosphere in about a year. If ocean fertilization could reduce atmospheric CO2 concentrations, it would also reduce surface ocean dissolved inorganic carbon concentrations, and thus diminish the degree of ocean acidification. To evaluate this line of thinking, we use a global ocean carbon cycle model with a simple representation of marine biology and investigate the maximum potential effect of ocean fertilization on ocean carbonate chemistry. We find that the effect of ocean fertilization on ocean acidification depends, in part, on the context in which ocean fertilization is performed. With fixed emissions of CO2 to the atmosphere, ocean fertilization moderately mitigates changes in ocean carbonate chemistry near the ocean surface, but at the expense of further acidifying the deep ocean. Under the SRES A2 CO2 emission scenario, by year 2100 simulated atmospheric CO2, global mean surface pH, and saturation state of aragonite is 965 ppm, 7.74, and 1.55 for the scenario without fertilization and 833 ppm, 7.80, and 1.71 for the scenario with 100-year (between 2000 and 2100) continuous fertilization for the global ocean (For comparison, pre-industrial global mean surface pH and saturation state of aragonite is 8.18 and 3.5). As a result of ocean fertilization, 10 years from now, the depth of saturation horizon (the depth below which ocean water is undersaturated with respect to calcium carbonate) for aragonite in the Southern Ocean shoals from its present average value of about 700 m to 100 m. In contrast, no significant change in the depth of aragonite saturation horizontal is seen in the scenario without fertilization for the corresponding period. By year 2100, global mean calcite saturation horizon shoals from its present value of 3150 m to 2965 and 2534 m in the case without fertilization and with it. In contrast, if the sale of carbon credits from ocean fertilization leads to greater CO2 emissions to the atmosphere (e.g., if carbon credits from ocean fertilization are used to offset CO2 emissions from a coal plant), then there is the potential that ocean fertilization would further acidify the deep ocean without conferring any chemical benefit to surface ocean waters.

Regional trends in aquatic recovery from acidification in North America and Europe

USGS Publications Warehouse

Stoddard, J.L.; Jeffries, D.S.; Lukewille, A.; Clair, T.A.; Dillon, P.J.; Driscoll, C.T.; Forsius, M.; Johannessen, M.; Kahl, J.S.; Kellogg, J.H.; Kemp, A.; Mannlo, J.; Monteith, D.T.; Murdoch, Peter S.; Patrick, S.; Rebsdorl, A.; Skjelkvale, B.L.; Stainton, M.P.; Traaen, T.; Van Dam, H.; Webster, K.E.; Wleting, J.; Wllander, A.

1999-01-01

Rates of acidic deposition from the atmosphere ('acid rain') have decreased throughout the 1980s and 1990s across large portions of North America and Europe. Many recent studies have attributed observed reversals in surface-water acidification at national and regional scales to the declining deposition. To test whether emissions regulations have led to widespread recovery in surface-water chemistry, we analysed regional trends between 1980 and 1995 in indicators of acidification (sulphate, nitrate and base-cation concentrations, and measured (Gran) alkalinity) for 205 lakes and streams in eight regions of North America and Europe. Dramatic differences in trend direction and strength for the two decades are apparent. In concordance with general temporal trends in acidic deposition, lake and stream sulphate concentrations decreased in all regions with the exception of Great Britain all but one of these regions exhibited stronger downward trends in the 1990s than in the 1980s. In contrast, regional declines in lake and stream nitrate concentrations were rare and, when detected, were very small. Recovery in alkalinity, expected wherever strong regional declines in sulphate concentrations have occurred, was observed in all regions of Europe, especially in the 1990s, but in only one region (of five) in North America. We attribute the lack of recovery in three regions (south/central Ontario, the Adirondack/Catskill mountains and midwestern North America) to strong regional declines in base-cation concentrations that exceed the decreases in sulphate concentrations.

Predicting watershed acidification under alternate rainfall conditions

USGS Publications Warehouse

Huntington, T.G.

1996-01-01

The effect of alternate rainfall scenarios on acidification of a forested watershed subjected to chronic acidic deposition was assessed using the model of acidification of groundwater in catchments (MAGIC). The model was calibrated at the Panola Mountain Research Watershed, near Atlanta, Georgia, U.S.A. using measured soil properties, wet and dry deposition, and modeled hydrologic routing. Model forecast simulations were evaluated to compare alternate temporal averaging of rainfall inputs and variations in rainfall amount and seasonal distribution. Soil water alkalinity was predicted to decrease to substantially lower concentrations under lower rainfall compared with current or higher rainfall conditions. Soil water alkalinity was also predicted to decrease to lower levels when the majority of rainfall occurred during the growing season compared with other rainfall distributions. Changes in rainfall distribution that result in decreases in net soil water flux will temporarily delay acidification. Ultimately, however, decreased soil water flux will result in larger increases in soil- adsorbed sulfur and soil-water sulfate concentrations and decreases in alkalinity when compared to higher water flux conditions. Potential climate change resulting in significant changes in rainfall amounts, seasonal distribution of rainfall, or evapotranspiration will change net soil water flux and, consequently, will affect the dynamics of the acidification response to continued sulfate loading.

Effect of sewage sludge on formation of acidic ground water at a reclaimed coal mine

USGS Publications Warehouse

Cravotta, C.A.

1998-01-01

Data on rock, ground water, vadose water, and vadose gas chemistry were collected for two years after sewage sludge was applied at a reclaimed surface coal mine in Pennsylvania to determine if surface-applied sludge is an effective barrier to oxygen influx, contributes metals and nutrients to ground water, and promotes the acidification of ground water. Acidity, sulfate, and metals concentrations were elevated in the ground water (6- to 21-m depth) from spoil relative to unmined rock because of active oxidation of pyrite and dissolution of aluminosilicate, carbonate, and Mn-Fe-oxide minerals in the spoil. Concentrations of acidity, sulfate, metals (Fe, Mn, Al, Cd, Cu, Cr, Ni, Zn), and nitrate, and abundances of iron-oxidizing bacteria were elevated in the ground water from sludge-treated spoil relative to untreated spoil having a similar mineral composition; however, gaseous and dissolved oxygen concentrations did not differ between the treatments. Abundances of iron-oxidizing bacteria in the ground water samples were positively correlated with concentrations of ammonia, nitrate, acidity, metals, and sulfate. Concentrations of metals in vadose water samples (<5-m depth) from sludge-treated spoil (pH 5.9) were not elevated relative to untreated spoil (pH 4.4). In contrast, concentrations of nitrate were elevated in vadose water samples from sludge-treated spoil, frequently exceeding 10 mg/L. Downgradient decreases in nitrate to less than 3 mg/L and increases in sulfate concentrations in underlying ground water could result from oxidation of pyrite by nitrate. Thus, sewage sludge added to pyritic spoil can increase the growth of iron-oxidizing bacteria, the oxidation of pyrite, and the acidification of ground water. Nevertheless, the overall effects on ground water chemistry from the sludge were small and probably short-lived relative to the effects from mining only.

Effects of ocean acidification, warming and melting of sea ice on aragonite saturation of the Canada Basin surface water

NASA Astrophysics Data System (ADS)

Yamamoto-Kawai, M.; McLaughlin, F. A.; Carmack, E. C.

2011-02-01

In 2008, surface waters in the Canada Basin of the Arctic Ocean were found to be undersaturated with respect to aragonite. This is associated with recent extensive melting of sea ice in this region, as well as elevated sea surface temperature and atmospheric CO2 concentrations. We have estimated the relative contribution of each of these controlling factors to the calcium carbonate saturation state (Ω) from observations of dissolved inorganic carbon, total alkalinity and oxygen isotope ratio. Results indicate that the increase in atmospheric CO2 has lowered surface Ω by ˜0.3 in the Canada Basin since the preindustrial period. Recent melting of sea ice has further lowered mean Ω by 0.4, and of this, half was due to dilution of surface water and half was due to the change in air-sea disequilibrium state. Surface water warming has generally counteracted the mean decrease in Ω by 0.1.

Potential impact of acid precipitation on arsenic and selenium.

PubMed Central

Mushak, P

1985-01-01

The potential impact of acidic precipitation on the environmental mobility of the metalloids arsenic (As) and selenium (Se) has not been given much attention and is poorly understood. As with other elements, the interest here is the potential effect of environmental acidification on environmental behavior in ways that are relevant to human exposure to these metalloids. Available information on acid precipitation and the environmental behavior of these metalloids do, however, permit some preliminary conclusions to be drawn. Both As and Se appear to be mobilized from household plumbing into tap water by the corrosive action of soft, mildly acidic water, while surface water catchment systems in areas impacted by acidic deposition may contain elevated soluble As levels. Acidification of aquatic ecosystems that are drinking water sources may pose the prospect of enhanced release of As from sediment to water as well as reduction in water levels of Se. Acidification of ground waters, where As appears to be especially mobile, is of particular concern in this regard. The potential impact of acidic deposition on As and Se in soils cannot readily be assessed with respect to human exposure, but it would appear that the behavior of these metalloids in poorly buffered, poorly immobilizing soils, e.g., sandy soils of low metal hydrous oxide content, would be most affected. The effect is opposite for the two elements; lowered pH would appear to enhance As mobility and to reduce Se availability. Altered acidity of both soil and aquatic systems poses a risk for altered biotransformation processes involving both As and Se, thereby affecting the relative amounts of different chemical forms varying in their toxicity to humans as well as influencing biogeochemical cycling. PMID:4076075

Potential impact of acid precipitation on arsenic and selenium.

PubMed

Mushak, P

1985-11-01

The potential impact of acidic precipitation on the environmental mobility of the metalloids arsenic (As) and selenium (Se) has not been given much attention and is poorly understood. As with other elements, the interest here is the potential effect of environmental acidification on environmental behavior in ways that are relevant to human exposure to these metalloids. Available information on acid precipitation and the environmental behavior of these metalloids do, however, permit some preliminary conclusions to be drawn. Both As and Se appear to be mobilized from household plumbing into tap water by the corrosive action of soft, mildly acidic water, while surface water catchment systems in areas impacted by acidic deposition may contain elevated soluble As levels. Acidification of aquatic ecosystems that are drinking water sources may pose the prospect of enhanced release of As from sediment to water as well as reduction in water levels of Se. Acidification of ground waters, where As appears to be especially mobile, is of particular concern in this regard. The potential impact of acidic deposition on As and Se in soils cannot readily be assessed with respect to human exposure, but it would appear that the behavior of these metalloids in poorly buffered, poorly immobilizing soils, e.g., sandy soils of low metal hydrous oxide content, would be most affected. The effect is opposite for the two elements; lowered pH would appear to enhance As mobility and to reduce Se availability. Altered acidity of both soil and aquatic systems poses a risk for altered biotransformation processes involving both As and Se, thereby affecting the relative amounts of different chemical forms varying in their toxicity to humans as well as influencing biogeochemical cycling.

Ecological effects of nitrogen and sulfur air pollution in the US: what do we know?

USGS Publications Warehouse

Greaver, Tara L.; Sullivan, Timothy J.; Herrick, Jeffrey D.; Barber, Mary C.; Baron, Jill S.; Cosby, Bernard J.; Deerhake, Marion E.; Dennis, Robin L.; Dubois, Jean-Jacque B.; Goodale, Christine L.; Herlihy, Alan T.; Lawrence, Gregory B.; Liu, Lingli; Lynch, Jason A.; Novak, Kristopher J.

2012-01-01

Four decades after the passage of the US Clean Air Act, air-quality standards are set to protect ecosystems from damage caused by gas-phase nitrogen (N) and sulfur (S) compounds, but not from the deposition of these air pollutants to land and water. Here, we synthesize recent scientific literature on the ecological effects of N and S air pollution in the US. Deposition of N and S is the main driver of ecosystem acidification and contributes to nutrient enrichment in many natural systems. Although surface-water acidification has decreased in the US since 1990, it remains a problem in many regions. Perturbations to ecosystems caused by the nutrient effects of N deposition continue to emerge, although gas-phase concentrations are generally not high enough to cause phytotoxicity. In all, there is overwhelming evidence of a broad range of damaging effects to ecosystems in the US under current air quality conditions.

Severity of ocean acidification following the end-Cretaceous asteroid impact

PubMed Central

Tyrrell, Toby; Armstrong McKay, David Ian

2015-01-01

Most paleo-episodes of ocean acidification (OA) were either too slow or too small to be instructive in predicting near-future impacts. The end-Cretaceous event (66 Mya) is intriguing in this regard, both because of its rapid onset and also because many pelagic calcifying species (including 100% of ammonites and more than 90% of calcareous nannoplankton and foraminifera) went extinct at this time. Here we evaluate whether extinction-level OA could feasibly have been produced by the asteroid impact. Carbon cycle box models were used to estimate OA consequences of (i) vaporization of up to 60 × 1015 mol of sulfur from gypsum rocks at the point of impact; (ii) generation of up to 5 × 1015 mol of NOx by the impact pressure wave and other sources; (iii) release of up to 6,500 Pg C as CO2 from vaporization of carbonate rocks, wildfires, and soil carbon decay; and (iv) ocean overturn bringing high-CO2 water to the surface. We find that the acidification produced by most processes is too weak to explain calcifier extinctions. Sulfuric acid additions could have made the surface ocean extremely undersaturated (Ωcalcite <0.5), but only if they reached the ocean very rapidly (over a few days) and if the quantity added was at the top end of literature estimates. We therefore conclude that severe ocean acidification might have been, but most likely was not, responsible for the great extinctions of planktonic calcifiers and ammonites at the end of the Cretaceous. PMID:25964350

Severity of ocean acidification following the end-Cretaceous asteroid impact.

PubMed

Tyrrell, Toby; Merico, Agostino; Armstrong McKay, David Ian

2015-05-26

Most paleo-episodes of ocean acidification (OA) were either too slow or too small to be instructive in predicting near-future impacts. The end-Cretaceous event (66 Mya) is intriguing in this regard, both because of its rapid onset and also because many pelagic calcifying species (including 100% of ammonites and more than 90% of calcareous nannoplankton and foraminifera) went extinct at this time. Here we evaluate whether extinction-level OA could feasibly have been produced by the asteroid impact. Carbon cycle box models were used to estimate OA consequences of (i) vaporization of up to 60 × 10(15) mol of sulfur from gypsum rocks at the point of impact; (ii) generation of up to 5 × 10(15) mol of NOx by the impact pressure wave and other sources; (iii) release of up to 6,500 Pg C as CO2 from vaporization of carbonate rocks, wildfires, and soil carbon decay; and (iv) ocean overturn bringing high-CO2 water to the surface. We find that the acidification produced by most processes is too weak to explain calcifier extinctions. Sulfuric acid additions could have made the surface ocean extremely undersaturated (Ωcalcite <0.5), but only if they reached the ocean very rapidly (over a few days) and if the quantity added was at the top end of literature estimates. We therefore conclude that severe ocean acidification might have been, but most likely was not, responsible for the great extinctions of planktonic calcifiers and ammonites at the end of the Cretaceous.

Monitoring and assessment of ocean acidification in the Arctic Ocean-A scoping paper

USGS Publications Warehouse

Robbins, Lisa L.; Yates, Kimberly K.; Feely, Richard; Fabry, Victoria

2010-01-01

Carbon dioxide (CO2) in the atmosphere is absorbed at the ocean surface by reacting with seawater to form a weak, naturally occurring acid called carbonic acid. As atmospheric carbon dioxide increases, the concentration of carbonic acid in seawater also increases, causing a decrease in ocean pH and carbonate mineral saturation states, a process known as ocean acidification. The oceans have absorbed approximately 525 billion tons of carbon dioxide from the atmosphere, or about one-quarter to one-third of the anthropogenic carbon emissions released since the beginning of the Industrial Revolution. Global surveys of ocean chemistry have revealed that seawater pH has decreased by about 0.1 units (from a pH of 8.2 to 8.1) since the 1700s due to absorption of carbon dioxide (Raven and others, 2005). Modeling studies, based on Intergovernmental Panel on Climate Change (IPCC) CO2 emission scenarios, predict that atmospheric carbon dioxide levels could reach more than 500 parts per million (ppm) by the middle of this century and 800 ppm by the year 2100, causing an additional decrease in surface water pH of 0.3 pH units. Ocean acidification is a global threat and is already having profound and deleterious effects on the geology, biology, chemistry, and socioeconomic resources of coastal and marine habitats. The polar and sub-polar seas have been identified as the bellwethers for global ocean acidification.

Redox reactions and weak buffering capacity lead to acidification in the Chesapeake Bay.

PubMed

Cai, Wei-Jun; Huang, Wei-Jen; Luther, George W; Pierrot, Denis; Li, Ming; Testa, Jeremy; Xue, Ming; Joesoef, Andrew; Mann, Roger; Brodeur, Jean; Xu, Yuan-Yuan; Chen, Baoshan; Hussain, Najid; Waldbusser, George G; Cornwell, Jeffrey; Kemp, W Michael

2017-08-28

The combined effects of anthropogenic and biological CO 2 inputs may lead to more rapid acidification in coastal waters compared to the open ocean. It is less clear, however, how redox reactions would contribute to acidification. Here we report estuarine acidification dynamics based on oxygen, hydrogen sulfide (H 2 S), pH, dissolved inorganic carbon and total alkalinity data from the Chesapeake Bay, where anthropogenic nutrient inputs have led to eutrophication, hypoxia and anoxia, and low pH. We show that a pH minimum occurs in mid-depths where acids are generated as a result of H 2 S oxidation in waters mixed upward from the anoxic depths. Our analyses also suggest a large synergistic effect from river-ocean mixing, global and local atmospheric CO 2 uptake, and CO 2 and acid production from respiration and other redox reactions. Together they lead to a poor acid buffering capacity, severe acidification and increased carbonate mineral dissolution in the USA's largest estuary.The potential contribution of redox reactions to acidification in coastal waters is unclear. Here, using measurements from the Chesapeake Bay, the authors show that pH minimum occurs at mid-depths where acids are produced via hydrogen sulfide oxidation in waters mixed upward from anoxic depths.

6.0 Monitoring recovery from calcium depletion and nitrogen saturation

Treesearch

Walter C. Shortle; Peter S. Murdoch; Kevin T. Smith; Rakesh Minocha; Gregory B. Lawrence

2008-01-01

Atmospheric emissions from industrial processes in the early part of the 20th century resulted in acidic deposition in the Northeastern U.S., a phenomenon known as "acid rain." Acid rain has been implicated in acidification of sensitive waterways, nitrate enrichment of surface waters, and fish population declines in poorly buffered mountain streams (Baldigo...

Long-Term Experimental Acidification Drives Watershed Scale Shift in Dissolved Organic Matter Composition and Flux

Treesearch

Michael D. SanClements; Ivan J. Fernandez; Robert H. Lee; Joshua A. Roberti; Mary Beth Adams; Garret A. Rue; Diane M. McKnight

2018-01-01

Over the last several decades dissolved organic carbon concentrations (DOC) in surface waters have increased throughout much of the northern hemisphere. Several hypotheses have been proposed regarding the drivers of this phenomenon including decreased sulfur (S) deposition working via an acidity- change mechanism. Using fluorescence spectroscopy and data from two long-...

Precipitation-mediated responses of soil acid buffering capacity to long-term nitrogen addition in a semi-arid grassland

NASA Astrophysics Data System (ADS)

Cai, Jiangping; Luo, Wentao; Liu, Heyong; Feng, Xue; Zhang, Yongyong; Wang, Ruzhen; Xu, Zhuwen; Zhang, Yuge; Jiang, Yong

2017-12-01

Atmospheric nitrogen (N) deposition can result in soil acidification and reduce soil acid buffering capacity. However, it remains poorly understood how changes in precipitation regimes with elevated atmospheric N deposition affect soil acidification processes in a water-limited grassland. Here, we conducted a 9-year split-plot experiment with water addition as the main factor and N addition as the second factor. Results showed that soil acid buffering capacity significantly decreased with increased N inputs, mainly due to the decline of soil effective cation exchange capacity (ECEC) and exchangeable basic cations (especially Ca2+), indicating an acceleration of soil acidification status in this steppes. Significant interactive N and water effects were detected on the soil acid buffering capacity. Water addition enhanced the soil ECEC and exchangeable base cations and thus alleviated the decrease of soil acid buffering capacity under N addition. Our findings suggested that precipitation can mitigate the impact of increased N deposition on soil acidification in semi-arid grasslands. This knowledge should be used to improve models predicting soil acidification processes in terrestrial ecosystems under changing environmental conditions.

Seaweed fails to prevent ocean acidification impact on foraminifera along a shallow-water CO2 gradient.

PubMed

Pettit, Laura R; Smart, Christopher W; Hart, Malcolm B; Milazzo, Marco; Hall-Spencer, Jason M

2015-05-01

Ocean acidification causes biodiversity loss, alters ecosystems, and may impact food security, as shells of small organisms dissolve easily in corrosive waters. There is a suggestion that photosynthetic organisms could mitigate ocean acidification on a local scale, through seagrass protection or seaweed cultivation, as net ecosystem organic production raises the saturation state of calcium carbonate making seawater less corrosive. Here, we used a natural gradient in calcium carbonate saturation, caused by shallow-water CO2 seeps in the Mediterranean Sea, to assess whether seaweed that is resistant to acidification (Padina pavonica) could prevent adverse effects of acidification on epiphytic foraminifera. We found a reduction in the number of species of foraminifera as calcium carbonate saturation state fell and that the assemblage shifted from one dominated by calcareous species at reference sites (pH ∼8.19) to one dominated by agglutinated foraminifera at elevated levels of CO2 (pH ∼7.71). It is expected that ocean acidification will result in changes in foraminiferal assemblage composition and agglutinated forms may become more prevalent. Although Padina did not prevent adverse effects of ocean acidification, high biomass stands of seagrass or seaweed farms might be more successful in protecting epiphytic foraminifera.

Seaweed fails to prevent ocean acidification impact on foraminifera along a shallow-water CO2 gradient

PubMed Central

Pettit, Laura R; Smart, Christopher W; Hart, Malcolm B; Milazzo, Marco; Hall-Spencer, Jason M

2015-01-01

Ocean acidification causes biodiversity loss, alters ecosystems, and may impact food security, as shells of small organisms dissolve easily in corrosive waters. There is a suggestion that photosynthetic organisms could mitigate ocean acidification on a local scale, through seagrass protection or seaweed cultivation, as net ecosystem organic production raises the saturation state of calcium carbonate making seawater less corrosive. Here, we used a natural gradient in calcium carbonate saturation, caused by shallow-water CO2 seeps in the Mediterranean Sea, to assess whether seaweed that is resistant to acidification (Padina pavonica) could prevent adverse effects of acidification on epiphytic foraminifera. We found a reduction in the number of species of foraminifera as calcium carbonate saturation state fell and that the assemblage shifted from one dominated by calcareous species at reference sites (pH ∼8.19) to one dominated by agglutinated foraminifera at elevated levels of CO2 (pH ∼7.71). It is expected that ocean acidification will result in changes in foraminiferal assemblage composition and agglutinated forms may become more prevalent. Although Padina did not prevent adverse effects of ocean acidification, high biomass stands of seagrass or seaweed farms might be more successful in protecting epiphytic foraminifera. PMID:26140195

Anthropogenic CO2 in a dense water formation area of the Mediterranean Sea

NASA Astrophysics Data System (ADS)

Ingrosso, Gianmarco; Bensi, Manuel; Cardin, Vanessa; Giani, Michele

2017-05-01

There is growing evidence that the on-going ocean acidification of the Mediterranean Sea could be favoured by its active overturning circulation. The areas of dense water formation are, indeed, preferential sites for atmospheric carbon dioxide absorption and through them the ocean acidification process can quickly propagate into the deep layers. In this study we estimated the concentration of anthropogenic CO2 (Cant) in the dense water formation areas of the middle and southern Adriatic Sea. Using the composite tracer TrOCA (Tracer combining Oxygen, inorganic Carbon, and total Alkalinity) and carbonate chemistry data collected throughout March 2013, our results revealed that a massive amount of Cant has invaded all the identified water masses. High Cant concentration was detected at the bottom layer of the Pomo Pit (middle Adriatic, 96.8±9.7 μmol kg-1) and Southern Adriatic Pit (SAP, 85.2±9.4 μmol kg-1), associated respectively with the presence of North Adriatic Dense Water (NAdDW) and Adriatic Dense Water (AdDW). This anthropogenic contamination was clearly linked to the dense water formation events, which govern strong CO2 flux from the atmosphere to the sea and the sinking of dense, CO2-rich surface waters to the deep sea. However, a very high Cant level (94.5±12.5 μmol kg-1) was also estimated at the intermediate layer, as a consequence of a recent vertical mixing that determined the physical and biogeochemical modification of the water of Levantine origin (i.e. Modified Levantine Intermediate Water, MLIW) and favoured the atmospheric CO2 intrusion. The penetration of Cant in the Adriatic Sea determined a significant pH reduction since the pre-industrial era (- 0.139±0.019 pH units on average). This estimation was very similar to the global Mediterranean Sea acidification, but it was again more pronounced at the bottom of the Pomo Pit, within the layer occupied by NAdDW (- 0.157±0.018 pH units), and at the intermediate layer of the recently formed MLIW (- 0.143±0.020 pH units). Our results indicate that the Adriatic Sea could potentially be one of the Mediterranean regions most affected by the ocean acidification and also demonstrate its active role in sequestering and storing Cant.

Atmospheric Deposition and Surface-Water Chemistry in Mount Rainier and North Cascades National Parks, U.S.A., Water Years 2000 and 2005-2006

USGS Publications Warehouse

Clow, David W.; Campbell, Donald H.

2008-01-01

High-elevation aquatic ecosystems in Mount Rainier and North Cascades National Parks are highly sensitive to atmospheric deposition of nitrogen and sulfur. Thin, rocky soils promote fast hydrologic flushing rates during snowmelt and rain events, limiting the ability of basins to neutralize acidity and assimilate nitrogen deposited from the atmosphere. Potential effects of nitrogen and sulfur deposition include episodic or chronic acidification of terrestrial and aquatic ecosystems. In addition, nitrogen deposition can cause eutrophication of water bodies and changes in species composition in lakes and streams. This report documents results of a study performed by the U.S. Geological Survey, in cooperation with the National Park Service, of the effects of atmospheric deposition of nitrogen and sulfur on surface-water chemistry in Mount Rainier and North Cascades National Parks. Inorganic nitrogen in wet deposition was highest in the vicinity of North Cascades National Park, perhaps due to emissions from human sources and activities in the Puget Sound area. Sulfur in wet deposition was highest near the Pacific coast, reflecting the influence of marine aerosols. Dry deposition generally accounted for less than 30 percent of wet plus dry inorganic nitrogen and sulfur deposition, but occult deposition (primarily fog) represents a potentially substantial unmeasured component of total deposition. Trend analyses indicate inorganic nitrogen in wet deposition was relatively stable during 1986-2005, but sulfur in wet deposition declined substantially during that time, particularly after 2001, when emissions controls were added to a large powerplant in western Washington. Surface-water sulfate concentrations at the study site nearest the powerplant showed a statistically significant decrease between 2000 and 2005-06, but there was no statistically significant change in alkalinity, indicating a delayed response in surface-water alkalinity. Seasonal patterns in surface-water chemistry and streamflow are strongly influenced by melting of seasonal snowpacks, which release large amounts of dilute, slightly acidic water to terrestrial and aquatic ecosystems during spring snowmelt. Concentrations of sulfate, alkalinity, and base cations in surface water declined rapidly during snowmelt, then gradually recovered during summer and fall. Preferential elution of acidic solutes from the snowpack at the beginning of snowmelt may cause episodic acidification in small alpine streams; evidence is provided by a stream sample collected at one of the sites during spring 2006 that was acidic (pH = 4.8, alkalinity = -18 microequivalents per liter) and had high concentrations of nitrate and sulfate and low concentrations of weathering products. Rain-on-snow events caused sharp declines in specific conductance, which was measured continuously using an in-stream sensor. A strong correlation was observed between measured specific conductance and measured alkalinity (r2 = 0.76), permitting estimation of alkalinity from specific-conductance data using a regression equation. Estimated alkalinity declined by an order of magnitude during the rain-on-snow events, in one case to 8 microequivalents per liter. Actual declines in alkalinity might be greater because the regression equation accounts only for dilution effects; at low concentrations, the relation between specific conductance and alkalinity is likely to be nonlinear and have a negative intercept (negative alkalinity). Thus, episodic acidification is possible during rain-on-snow events. The scale of episodic acidification is unknown, but if it occurs, it could have detrimental effects on aquatic life and amphibians. Historical lake-survey data indicate that most lakes are oligotrophic and have low nitrogen and phosphorus concentrations. Nitrogen limitation is more common in lakes in Mount Rainier National Park than in North Cascades National Park due to higher nitrate concentrations at North Cascades. T

Combined effects of sea water acidification and copper exposure on the symbiont-bearing foraminifer Amphistegina gibbosa

NASA Astrophysics Data System (ADS)

Marques, Joseane Aparecida; de Barros Marangoni, Laura Fernandes; Bianchini, Adalto

2017-06-01

Coral reefs are threatened by global and local stressors such as ocean acidification and trace metal contamination. Reliable early warning monitoring tools are needed to assess and monitor coral reef health. Symbiont-bearing foraminifers ( Amphistegina gibbosa) were kept under ambient conditions (no sea water acidification and no copper addition) or exposed to combinations of different levels of sea water pH (8.1, 7.8, 7.5 and 7.2) and environmentally relevant concentrations of dissolved copper (measured: 1.0, 1.6, 2.3 and 3.2 µg L-1) in a mesocosm system. After 10- and 25-d exposure, foraminifers were analyzed for holobiont Ca2+-ATPase activity, bleaching, growth and mortality. Enzyme activity was inhibited in foraminifers exposed to pH 7.2 and 3.2 µg L-1 Cu for 25 d. Bleaching frequency was also higher at pH 7.2 combined with copper addition. There was no significant effect of sea water acidification and copper addition on mortality. However, test size was smaller in foraminifers exposed to copper, with a positive interactive effect of sea water acidification. These findings can be explained by the higher availability of free copper ions at lower water pH. This condition would increase Cu competition with Ca2+ for the binding sites on the organism, thus inhibiting Ca2+-ATPase activity and affecting the organism's overall fitness. Findings reported here suggest that key processes in A. gibbosa, such as calcification and photosynthesis, are affected by the combined effect of global (sea water acidification) and local (copper contamination) stressors. Considering the experimental conditions employed (mesocosm system, possible ocean acidification scenarios, low copper concentrations, biomarkers of ecological relevance and chronic exposure), our findings support the use of foraminifera and biomarkers analyzed in the present study as reliable tools to detect and monitor the ecological impacts of multiple stressors in coral reef environments.

Seasonal carbonate chemistry covariation with temperature, oxygen, and salinity in a fjord estuary: implications for the design of ocean acidification experiments.

PubMed

Reum, Jonathan C P; Alin, Simone R; Feely, Richard A; Newton, Jan; Warner, Mark; McElhany, Paul

2014-01-01

Carbonate chemistry variability is often poorly characterized in coastal regions and patterns of covariation with other biologically important variables such as temperature, oxygen concentration, and salinity are rarely evaluated. This absence of information hampers the design and interpretation of ocean acidification experiments that aim to characterize biological responses to future pCO2 levels relative to contemporary conditions. Here, we analyzed a large carbonate chemistry data set from Puget Sound, a fjord estuary on the U.S. west coast, and included measurements from three seasons (winter, summer, and fall). pCO2 exceeded the 2008-2011 mean atmospheric level (392 µatm) at all depths and seasons sampled except for the near-surface waters (< 10 m) in the summer. Further, undersaturated conditions with respect to the biogenic carbonate mineral aragonite were widespread (Ωar<1). We show that pCO2 values were relatively uniform throughout the water column and across regions in winter, enriched in subsurface waters in summer, and in the fall some values exceeded 2500 µatm in near-surface waters. Carbonate chemistry covaried to differing levels with temperature and oxygen depending primarily on season and secondarily on region. Salinity, which varied little (27 to 31), was weakly correlated with carbonate chemistry. We illustrate potential high-frequency changes in carbonate chemistry, temperature, and oxygen conditions experienced simultaneously by organisms in Puget Sound that undergo diel vertical migrations under present-day conditions. We used simple calculations to estimate future pCO2 and Ωar values experienced by diel vertical migrators based on an increase in atmospheric CO2. Given the potential for non-linear interactions between pCO2 and other abiotic variables on physiological and ecological processes, our results provide a basis for identifying control conditions in ocean acidification experiments for this region, but also highlight the wide range of carbonate chemistry conditions organisms may currently experience in this and similar coastal ecosystems.

Seasonal Carbonate Chemistry Covariation with Temperature, Oxygen, and Salinity in a Fjord Estuary: Implications for the Design of Ocean Acidification Experiments

PubMed Central

Reum, Jonathan C. P.; Alin, Simone R.; Feely, Richard A.; Newton, Jan; Warner, Mark; McElhany, Paul

2014-01-01

Carbonate chemistry variability is often poorly characterized in coastal regions and patterns of covariation with other biologically important variables such as temperature, oxygen concentration, and salinity are rarely evaluated. This absence of information hampers the design and interpretation of ocean acidification experiments that aim to characterize biological responses to future pCO2 levels relative to contemporary conditions. Here, we analyzed a large carbonate chemistry data set from Puget Sound, a fjord estuary on the U.S. west coast, and included measurements from three seasons (winter, summer, and fall). pCO2 exceeded the 2008–2011 mean atmospheric level (392 µatm) at all depths and seasons sampled except for the near-surface waters (< 10 m) in the summer. Further, undersaturated conditions with respect to the biogenic carbonate mineral aragonite were widespread (Ωar<1). We show that pCO2 values were relatively uniform throughout the water column and across regions in winter, enriched in subsurface waters in summer, and in the fall some values exceeded 2500 µatm in near-surface waters. Carbonate chemistry covaried to differing levels with temperature and oxygen depending primarily on season and secondarily on region. Salinity, which varied little (27 to 31), was weakly correlated with carbonate chemistry. We illustrate potential high-frequency changes in carbonate chemistry, temperature, and oxygen conditions experienced simultaneously by organisms in Puget Sound that undergo diel vertical migrations under present-day conditions. We used simple calculations to estimate future pCO2 and Ωar values experienced by diel vertical migrators based on an increase in atmospheric CO2. Given the potential for non-linear interactions between pCO2 and other abiotic variables on physiological and ecological processes, our results provide a basis for identifying control conditions in ocean acidification experiments for this region, but also highlight the wide range of carbonate chemistry conditions organisms may currently experience in this and similar coastal ecosystems. PMID:24586915

Insights into Ocean Acidification During the Middle Eocene Climatic Optimum from Boron Isotopes at Southern Ocean Site 738

NASA Astrophysics Data System (ADS)

Moebius, I.; Hoenisch, B.; Friedrich, O.

2015-12-01

The Middle Eocene Climatic Optimum (MECO) is a ~650-kyr interval of global warming, with a brief ~50 ky long peak warming interval, and an abrupt termination. Deep sea and surface ocean temperature evolution across this interval are fairly well constrained, but thus far we have little understanding of the mechanisms responsible for the gradual warming and rapid recovery. Carbonate mass accumulation rates suggest a shoaling of the carbonate compensation depth, and studies on alkenones indicate increasing atmospheric CO2 levels during the MECO. This suggests an increase in surface ocean CO2, and consequently ocean acidification. However, the severity and timing of the proposed ocean acidification with respect to the onset, peak warming and the termination are currently not well resolved. The boron isotopic composition (δ11B) recorded in planktic foraminifer shells offers an opportunity to infer oceanic pH across this interval. We are working on a boron isotope reconstruction from Southern Ocean IODP site 738 and South Atlantic IODP site 1263, covering 42.0 to 38.5 Ma. These sites are characterized by good carbonate preservation and well-defined age models have been established. Additionally, ecology, nutrient content and bottom-water oxygenation have been shown to change significantly across the event towards a more eutrophic, periodically oxygen-depleted environment supporting different biological communities. We selected the planktic foraminifera species Acarinina spinuloinflata for this study because it is symbiont-bearing, suggesting a near-surface habitat and little vertical migration in the water column, and because of its abundance in the samples. δ11B data will be translated to surface ocean pH and atmospheric pCO2 will be approximated to refine knowledge about the carbon cycle during this time. Parallel analysis of two core sites will help to evaluate the tenacity of the data.

Hydrogeochemical Processes Causing Persistent Low pH in Lakes within a Reclaimed Lignite Mine, East Texas

NASA Astrophysics Data System (ADS)

Paul, J. C.; Schwab, P.; Knappett, P.; Deng, Y.

2017-12-01

Surface water pH values ranging from 2.5 to 2.6 have been reported in three lakes at a reclaimed lignite mine located in the Wilcox Formation of East Texas (the site). Traditional neutralization processes using alkaline chemicals to neutralize the surface water were found to be temporary solutions at the site. Low pH conditions usually are caused by oxidation of pyritic materials in the original tailings, but that was not always apparent based on previous studies at this site. The objective of this study is to determine factors contributing to acid seepage to aid in developing pre- and post-mining strategies to mitigate persistent acidity in surface waters at this and other sites. Mineralogy, hydrogeology, and hydrogeochemical reactions were evaluated. A network of 30 wells was used to monitor the water table and chemistry of the shallow, unconfined aquifer surrounding the lakes. Pressure transducers were deployed in 18 of these wells and each of the lakes to measure high frequency water levels over approximately one year. These water levels were contoured to visualize changing hydraulic head over time and determine the correlation in time between ground water flow directions and local rainfall events. Boreholes at 15 of the monitoring wells were continuously cored, and samples were taken at selected depth intervals based on pH measurements. XRD, SEM, and TEM were used to determine the mineralogy of select soil samples. Ion chromatography was used to determine sulfate concentration, and ICP-MS was used to determine solute concentrations from water and digested soil samples. Framboidal and microcrystalline pyrite were identified in the vadose zone in silt and clay-sized fractions; these minerals have high surface area that is conducive to rapid oxidation and acidification as ground water permeates from the vadose into the saturated zone. Morphology in addition to quantity of weatherable pyrite plays a significant role in acidification. Computer models were used to evaluate the effect of dissolving and precipitating solid phases on water chemistry along identified subsurface flow pathways with a focus on metal sulfides and iron oxides as influential to acid mine seepage into the affected lakes.

Quantifying the role of forest soil and bedrock in the acid neutralization of surface water in steep hillslopes.

PubMed

Asano, Yuko; Uchida, Taro

2005-02-01

The role of soil and bedrock in acid neutralizing processes has been difficult to quantify because of hydrological and biogeochemical uncertainties. To quantify those roles, hydrochemical observations were conducted at two hydrologically well-defined, steep granitic hillslopes in the Tanakami Mountains of Japan. These paired hillslopes are similar except for their soils; Fudoji is leached of base cations (base saturation <6%), while Rachidani is covered with fresh soil (base saturation >30%), because the erosion rate is 100-1000 times greater. The results showed that (1) soil solution pH at the soil-bedrock interface at Fudoji (4.3) was significantly lower than that of Rachidani (5.5), (2) the hillslope discharge pH in both hillslopes was similar (6.7-6.8), and (3) at Fudoji, 60% of the base cations leaching from the hillslope were derived from bedrock, whereas only 20% were derived from bedrock in Rachidani. Further, previously published results showed that the stream pH could not be predicted from the acid deposition rate and soil base saturation status. These results demonstrate that bedrock plays an especially important role when the overlying soil has been leached of base cations. These results indicate that while the status of soil acidification is a first-order control on vulnerability to surface water acidification, in some cases such as at Fudoji, subsurface interaction with the bedrock determines the sensitivity of surface water to acidic deposition.

Ocean Acidification Refugia of the Florida Reef Tract

NASA Astrophysics Data System (ADS)

Manzello, D.; Enochs, I.; Melo, N.; Gledhill, D. K.; Johns, E. M.

2012-12-01

Ocean acidification (OA) is expected to reduce the calcification rates of marine organisms, yet we have little understanding of how OA will manifest within dynamic, real-world systems. Natural CO2, alkalinity, and salinity gradients can significantly alter local carbonate chemistry, and thereby create a range of susceptibility for different ecosystems to OA. As such, there is a need to characterize this natural variability of seawater carbonate chemistry, especially within coastal ecosystems. Since 2009, carbonate chemistry data have been collected on the Florida Reef Tract (FRT). During periods of heightened productivity, there is a net uptake of total CO2 (TCO2) which increases aragonite saturation state (Ωarag) values on inshore patch reefs of the upper FRT. These waters can exhibit greater Ωarag than what has been modeled for the tropical surface ocean during preindustrial times, with mean (± std. error) Ωarag-values in spring = 4.69 (± 0.101). Conversely, Ωarag-values on offshore reefs generally represent oceanic carbonate chemistries consistent with present day tropical surface ocean conditions. This gradient is opposite from what has been reported for other reef environments. We hypothesize this pattern is caused by the photosynthetic uptake of TCO2 mainly by seagrasses and, to a lesser extent, macroalgae in the inshore waters of the FRT. These inshore reef habitats are therefore potential acidification refugia that are defined not only in a spatial sense, but also in time; coinciding with seasonal productivity dynamics. Coral reefs located within or immediately downstream of seagrass beds may find refuge from OA.

Ocean Acidification Refugia of the Florida Reef Tract

PubMed Central

Manzello, Derek P.; Enochs, Ian C.; Melo, Nelson; Gledhill, Dwight K.; Johns, Elizabeth M.

2012-01-01

Ocean acidification (OA) is expected to reduce the calcification rates of marine organisms, yet we have little understanding of how OA will manifest within dynamic, real-world systems. Natural CO2, alkalinity, and salinity gradients can significantly alter local carbonate chemistry, and thereby create a range of susceptibility for different ecosystems to OA. As such, there is a need to characterize this natural variability of seawater carbonate chemistry, especially within coastal ecosystems. Since 2009, carbonate chemistry data have been collected on the Florida Reef Tract (FRT). During periods of heightened productivity, there is a net uptake of total CO2 (TCO2) which increases aragonite saturation state (Ωarag) values on inshore patch reefs of the upper FRT. These waters can exhibit greater Ωarag than what has been modeled for the tropical surface ocean during preindustrial times, with mean (± std. error) Ωarag-values in spring = 4.69 (±0.101). Conversely, Ωarag-values on offshore reefs generally represent oceanic carbonate chemistries consistent with present day tropical surface ocean conditions. This gradient is opposite from what has been reported for other reef environments. We hypothesize this pattern is caused by the photosynthetic uptake of TCO2 mainly by seagrasses and, to a lesser extent, macroalgae in the inshore waters of the FRT. These inshore reef habitats are therefore potential acidification refugia that are defined not only in a spatial sense, but also in time; coinciding with seasonal productivity dynamics. Coral reefs located within or immediately downstream of seagrass beds may find refuge from OA. PMID:22848575

Ocean acidification refugia of the Florida Reef Tract.

PubMed

Manzello, Derek P; Enochs, Ian C; Melo, Nelson; Gledhill, Dwight K; Johns, Elizabeth M

2012-01-01

Ocean acidification (OA) is expected to reduce the calcification rates of marine organisms, yet we have little understanding of how OA will manifest within dynamic, real-world systems. Natural CO(2), alkalinity, and salinity gradients can significantly alter local carbonate chemistry, and thereby create a range of susceptibility for different ecosystems to OA. As such, there is a need to characterize this natural variability of seawater carbonate chemistry, especially within coastal ecosystems. Since 2009, carbonate chemistry data have been collected on the Florida Reef Tract (FRT). During periods of heightened productivity, there is a net uptake of total CO(2) (TCO(2)) which increases aragonite saturation state (Ω(arag)) values on inshore patch reefs of the upper FRT. These waters can exhibit greater Ω(arag) than what has been modeled for the tropical surface ocean during preindustrial times, with mean (± std. error) Ω(arag)-values in spring = 4.69 (±0.101). Conversely, Ω(arag)-values on offshore reefs generally represent oceanic carbonate chemistries consistent with present day tropical surface ocean conditions. This gradient is opposite from what has been reported for other reef environments. We hypothesize this pattern is caused by the photosynthetic uptake of TCO(2) mainly by seagrasses and, to a lesser extent, macroalgae in the inshore waters of the FRT. These inshore reef habitats are therefore potential acidification refugia that are defined not only in a spatial sense, but also in time; coinciding with seasonal productivity dynamics. Coral reefs located within or immediately downstream of seagrass beds may find refuge from OA.

Ocean and Coastal Acidification off New England and Nova Scotia

EPA Science Inventory

New England coastal and adjacent Nova Scotia shelf waters have a reduced buffering capacity because of significant freshwater input, making the region’s waters potentially more vulnerable to coastal acidification. Nutrient loading and heavy precipitation events further acid...

A new mechanism for calcium loss in forest-floor soils

Treesearch

Gregory B. Lawrence; Mark B. David; Walter C. Shortle

1995-01-01

Calcium is the fifth most abundant element in trees, and is an essential component for wood formation and the maintenance of cell walls. Depletion of Ca from the rooting zone can result in acidification of soil and surface water and possibly growth decline and dieback of red spruce. During the past six decades, concentrations of root-available Ca (exchangeable and acid...

Hydrochloric acid: an overlooked driver of environmental change.

PubMed

Evans, Chris D; Monteith, Don T; Fowler, David; Cape, J Neil; Brayshaw, Susan

2011-03-01

Research on the ecosystem impacts of acidifying pollutants, and measures to control them, has focused almost exclusively on sulfur (S) and nitrogen (N) compounds. Hydrochloric acid (HCl), although emitted by coal burning, has been overlooked as a driver of ecosystem change because most of it was considered to redeposit close to emission sources rather than in remote natural ecosystems. Despite receiving little regulatory attention, measures to reduce S emissions, and changes in energy supply, have led to a 95% reduction in United Kingdom HCl emissions within 20 years. Long-term precipitation, surface water, and soil solution data suggest that the near-disappearance of HCl from deposition could account for 30-40% of chemical recovery from acidification during this time, affecting both near-source and remote areas. Because HCl is highly mobile in reducing environments, it is a more potent acidifier of wetlands than S or N, and HCl may have been the major driver of past peatland acidification. Reduced HCl loadings could therefore have affected the peatland carbon cycle, contributing to increases in dissolved organic carbon leaching to surface waters. With many regions increasingly reliant on coal for power generation, HCl should be recognized as a potentially significant constituent of resulting emissions, with distinctive ecosystem impacts.

Calcification rates and the effect of ocean acidification on Mediterranean cold-water corals

PubMed Central

Maier, C.; Watremez, P.; Taviani, M.; Weinbauer, M. G.; Gattuso, J. P.

2012-01-01

Global environmental changes, including ocean acidification, have been identified as a major threat to scleractinian corals. General predictions are that ocean acidification will be detrimental to reef growth and that 40 to more than 80 per cent of present-day reefs will decline during the next 50 years. Cold-water corals (CWCs) are thought to be strongly affected by changes in ocean acidification owing to their distribution in deep and/or cold waters, which naturally exhibit a CaCO3 saturation state lower than in shallow/warm waters. Calcification was measured in three species of Mediterranean cold-water scleractinian corals (Lophelia pertusa, Madrepora oculata and Desmophyllum dianthus) on-board research vessels and soon after collection. Incubations were performed in ambient sea water. The species M. oculata was additionally incubated in sea water reduced or enriched in CO2. At ambient conditions, calcification rates ranged between −0.01 and 0.23% d−1. Calcification rates of M. oculata under variable partial pressure of CO2 (pCO2) were the same for ambient and elevated pCO2 (404 and 867 µatm) with 0.06 ± 0.06% d−1, while calcification was 0.12 ± 0.06% d−1 when pCO2 was reduced to its pre-industrial level (285 µatm). This suggests that present-day CWC calcification in the Mediterranean Sea has already drastically declined (by 50%) as a consequence of anthropogenic-induced ocean acidification. PMID:22130603

Impacts of Ocean Acidification on Sediment Processes in Shallow Waters of the Arctic Ocean

PubMed Central

Gazeau, Frédéric; van Rijswijk, Pieter; Pozzato, Lara; Middelburg, Jack J.

2014-01-01

Despite the important roles of shallow-water sediments in global biogeochemical cycling, the effects of ocean acidification on sedimentary processes have received relatively little attention. As high-latitude cold waters can absorb more CO2 and usually have a lower buffering capacity than warmer waters, acidification rates in these areas are faster than those in sub-tropical regions. The present study investigates the effects of ocean acidification on sediment composition, processes and sediment-water fluxes in an Arctic coastal system. Undisturbed sediment cores, exempt of large dwelling organisms, were collected, incubated for a period of 14 days, and subject to a gradient of pCO2 covering the range of values projected for the end of the century. On five occasions during the experimental period, the sediment cores were isolated for flux measurements (oxygen, alkalinity, dissolved inorganic carbon, ammonium, nitrate, nitrite, phosphate and silicate). At the end of the experimental period, denitrification rates were measured and sediment samples were taken at several depth intervals for solid-phase analyses. Most of the parameters and processes (i.e. mineralization, denitrification) investigated showed no relationship with the overlying seawater pH, suggesting that ocean acidification will have limited impacts on the microbial activity and associated sediment-water fluxes on Arctic shelves, in the absence of active bio-irrigating organisms. Only following a pH decrease of 1 pH unit, not foreseen in the coming 300 years, significant enhancements of calcium carbonate dissolution and anammox rates were observed. Longer-term experiments on different sediment types are still required to confirm the limited impact of ocean acidification on shallow Arctic sediment processes as observed in this study. PMID:24718610

Impacts of ocean acidification on sediment processes in shallow waters of the Arctic Ocean.

PubMed

Gazeau, Frédéric; van Rijswijk, Pieter; Pozzato, Lara; Middelburg, Jack J

2014-01-01

Despite the important roles of shallow-water sediments in global biogeochemical cycling, the effects of ocean acidification on sedimentary processes have received relatively little attention. As high-latitude cold waters can absorb more CO2 and usually have a lower buffering capacity than warmer waters, acidification rates in these areas are faster than those in sub-tropical regions. The present study investigates the effects of ocean acidification on sediment composition, processes and sediment-water fluxes in an Arctic coastal system. Undisturbed sediment cores, exempt of large dwelling organisms, were collected, incubated for a period of 14 days, and subject to a gradient of pCO2 covering the range of values projected for the end of the century. On five occasions during the experimental period, the sediment cores were isolated for flux measurements (oxygen, alkalinity, dissolved inorganic carbon, ammonium, nitrate, nitrite, phosphate and silicate). At the end of the experimental period, denitrification rates were measured and sediment samples were taken at several depth intervals for solid-phase analyses. Most of the parameters and processes (i.e. mineralization, denitrification) investigated showed no relationship with the overlying seawater pH, suggesting that ocean acidification will have limited impacts on the microbial activity and associated sediment-water fluxes on Arctic shelves, in the absence of active bio-irrigating organisms. Only following a pH decrease of 1 pH unit, not foreseen in the coming 300 years, significant enhancements of calcium carbonate dissolution and anammox rates were observed. Longer-term experiments on different sediment types are still required to confirm the limited impact of ocean acidification on shallow Arctic sediment processes as observed in this study.

Building a new regulatory paradigm for coastal and estuarine acidification

NASA Astrophysics Data System (ADS)

Brodeur, J.; Cai, W. J.

2016-02-01

Ocean acidification regulation generally falls under the authority of the Clean Water Act (CWA, P.L. 92-500). The CWA has been a powerful tool to improve the country's water quality, but it is most adept at addressing point-source pollutants and contaminants. It requires policymakers to determine "natural levels" of the target pollutant and to attribute changes in water quality to a specific source, both of which are tough or impossible tests for the diffuse carbon imbalance that is associated with ocean acidification, even if we could easily identify the threshold level for harm to organisms (Boehm, 2015). Even where regulators have tried to apply CWA to address acidification, they have been confronted by a lack of baseline data, an inability to specifically identify sources within their jurisdiction, and the fact that existing water quality standards do not capture the impairments that are associated with ocean acidification (Cooley, 2015). In fact, there was a lawsuit brought by the Center for Biological Diversity against the U.S. Environmental Protection Agency (EPA) alleging the agency had failure to regulate this issue. In the end, the courts sided with the EPA, and it continues to struggle with how to use pH and/or saturation state to define a point at which a water body becomes impaired and a threat to sea-life and natural resources. We present an analysis of the complexities related to regulating ocean acidification, the history of work in this area, and suggest a solution that can be tailored to fit unique coastal and estuarine characteristics.

Building a new regulatory paradigm for coastal and estuarine acidification

NASA Astrophysics Data System (ADS)

Brodeur, J.; Cai, W. J.

2016-12-01

Ocean acidification regulation generally falls under the authority of the Clean Water Act (CWA, P.L. 92-500). The CWA has been a powerful tool to improve the country's water quality, but it is most adept at addressing point-source pollutants and contaminants. It requires policymakers to determine "natural levels" of the target pollutant and to attribute changes in water quality to a specific source, both of which are tough or impossible tests for the diffuse carbon imbalance that is associated with ocean acidification, even if we could easily identify the threshold level for harm to organisms (Boehm, 2015). Even where regulators have tried to apply CWA to address acidification, they have been confronted by a lack of baseline data, an inability to specifically identify sources within their jurisdiction, and the fact that existing water quality standards do not capture the impairments that are associated with ocean acidification (Cooley, 2015). In fact, there was a lawsuit brought by the Center for Biological Diversity against the U.S. Environmental Protection Agency (EPA) alleging the agency had failure to regulate this issue. In the end, the courts sided with the EPA, and it continues to struggle with how to use pH and/or saturation state to define a point at which a water body becomes impaired and a threat to sea-life and natural resources. We present an analysis of the complexities related to regulating ocean acidification, the history of work in this area, and suggest a solution that can be tailored to fit unique coastal and estuarine characteristics.

Over-calcified forms of the coccolithophore Emiliania huxleyi in high-CO2 waters are not preadapted to ocean acidification

NASA Astrophysics Data System (ADS)

von Dassow, Peter; Díaz-Rosas, Francisco; Mahdi Bendif, El; Gaitán-Espitia, Juan-Diego; Mella-Flores, Daniella; Rokitta, Sebastian; John, Uwe; Torres, Rodrigo

2018-03-01

Marine multicellular organisms inhabiting waters with natural high fluctuations in pH appear more tolerant to acidification than conspecifics occurring in nearby stable waters, suggesting that environments of fluctuating pH hold genetic reservoirs for adaptation of key groups to ocean acidification (OA). The abundant and cosmopolitan calcifying phytoplankton Emiliania huxleyi exhibits a range of morphotypes with varying degrees of coccolith mineralization. We show that E. huxleyi populations in the naturally acidified upwelling waters of the eastern South Pacific, where pH drops below 7.8 as is predicted for the global surface ocean by the year 2100, are dominated by exceptionally over-calcified morphotypes whose distal coccolith shield can be almost solid calcite. Shifts in morphotype composition of E. huxleyi populations correlate with changes in carbonate system parameters. We tested if these correlations indicate that the hyper-calcified morphotype is adapted to OA. In experimental exposures to present-day vs. future pCO2 (400 vs. 1200 µatm), the over-calcified morphotypes showed the same growth inhibition (-29.1±6.3 %) as moderately calcified morphotypes isolated from non-acidified water (-30.7±8.8 %). Under the high-CO2-low-pH condition, production rates of particulate organic carbon (POC) increased, while production rates of particulate inorganic carbon (PIC) were maintained or decreased slightly (but not significantly), leading to lowered PIC / POC ratios in all strains. There were no consistent correlations of response intensity with strain origin. The high-CO2-low-pH condition affected coccolith morphology equally or more strongly in over-calcified strains compared to moderately calcified strains. High-CO2-low-pH conditions appear not to directly select for exceptionally over-calcified morphotypes over other morphotypes, but perhaps indirectly by ecologically correlated factors. More generally, these results suggest that oceanic planktonic microorganisms, despite their rapid turnover and large population sizes, do not necessarily exhibit adaptations to naturally high-CO2 upwellings, and this ubiquitous coccolithophore may be near the limit of its capacity to adapt to ongoing ocean acidification.

Coral and mollusc resistance to ocean acidification adversely affected by warming

NASA Astrophysics Data System (ADS)

Rodolfo-Metalpa, R.; Houlbrèque, F.; Tambutté, É.; Boisson, F.; Baggini, C.; Patti, F. P.; Jeffree, R.; Fine, M.; Foggo, A.; Gattuso, J.-P.; Hall-Spencer, J. M.

2011-09-01

Increasing atmospheric carbon dioxide (CO2) concentrations are expectedto decrease surface ocean pH by 0.3-0.5 units by 2100 (refs , ), lowering the carbonate ion concentration of surfacewaters. This rapid acidification is predicted to dramatically decrease calcification in many marine organisms. Reduced skeletal growth under increased CO2 levels has already been shown for corals, molluscs and many other marine organisms. The impact of acidification on the ability of individual species to calcify has remained elusive, however, as measuring net calcification fails to disentangle the relative contributions of gross calcification and dissolution rates on growth. Here, we show that corals and molluscs transplanted along gradients of carbonate saturation state at Mediterranean CO2 vents are able to calcify and grow at even faster than normal rates when exposed to the high CO2 levels projected for the next 300 years. Calcifiers remain at risk, however, owing to the dissolution of exposed shells and skeletons that occurs as pH levels fall. Our results show that tissues and external organic layers play a major role in protecting shells and skeletons from corrosive sea water, limiting dissolution and allowing organisms to calcify. Our combined field and laboratory results demonstrate that the adverse effects of global warming are exacerbated when high temperatures coincide with acidification.

Early indications of soil recovery from acidic deposition in U.S. red spruce forests

Treesearch

Gregory B. Lawrence; Walter C. Shortle; Mark B. David; Kevin T. Smith; Richard A. Warby; Andrei G. Lapenis

2012-01-01

Forty to fifty percent decreases in acidic deposition through the 1980s and 1990s led to partial recovery of acidified surface waters in the northeastern United States; however, the limited number of studies that have assessed soil change found increased soil acidification during this period. From existing data, it's not clear whether soils continued to worsen in...

Infiltration and soil erosion modelling on Lausatian post mine sites

NASA Astrophysics Data System (ADS)

Kunth, Franziska; Schmidt, Jürgen

2013-04-01

Land management of reclaimed lignite mine sites requires long-term and safe structuring of recultivation areas. Erosion by water leads to explicit soil losses, especially on heavily endangered water repellent and non-vegetated soil surfaces. Beyond that, weathering of pyrite-containing lignite burden dumps causes sulfuric acid-formation, and hence the acidification of groundwater, seepage water and surface waters. Pyrite containing sediment is detached by precipitation and transported into worked-out open cuts by draining runoff. In addition to ground water influence, erosion processes are therefore involved in acidification of surface waters. A model-based approach for the conservation of man-made slopes of post mining sites is the objective of this ongoing study. The study shall be completed by modeling of the effectiveness of different mine site recultivation scenarios. Erosion risks on man-made slopes in recultivation areas should be determined by applying the physical, raster- and event based computer model EROSION 2D/3D (Schmidt, 1991, 1992; v. Werner, 1995). The widely used erosion model is able to predict runoff as well as detachment, transport and deposition of sediments. Lignite burden dumps contain hydrophobic substances that cover soil particles. Consequently, these soils show strong water repellency, which influences the processes of infiltration and soil erosion on non-vegetated, coal containing dump soils. The influence of water repellency had to be implemented into EROSION 2D/3D. Required input data for soil erosion modelling (e.g. physical soil parameters, infiltration rates, calibration factors, etc.) were gained by soil sampling and rainfall experiments on non-vegetated as well as recultivated reclaimed mine sites in the Lusatia lignite mining region (southeast of Berlin, Germany). The measured infiltration rates on the non-vegetated water repellent sites were extremely low. Therefore, a newly developed water repellency-factor was applied to depict infiltration and erosion processes on water repellent dump soils. For infiltration modelling with EROSION 2D calibration factors (e.g. water repellency factor, skin-factor, etc.) were determined in different steps by calibrating computer modelled infiltration, respectively volume rate of flow to the measured data.

Inverse coupling of DOC and nitrate export from soils and streams

NASA Astrophysics Data System (ADS)

Goodale, Christine

2013-04-01

Over the last two decades, nitrate concentrations in surface waters have decreased across the Northeastern United States and parts of northern Europe. Many hypotheses have been proposed to explain this decrease, but the cause remains unclear. One control may be associated with increasing abundance of dissolved organic carbon (DOC), which in turn may be a result of soil recovery from acidification. Compared across catchments, surface water NO3- decreases sharply with increasing DOC concentration. Here, we used measurements of soil and solution nitrate, DOC, and their isotopic composition (13C-DOC, 15N- and 18O-NO3) to test several related hypotheses that changing acidification affects the release of DOC and bio-available DOC (bDOC) from soil, and that variation in stocks of soil C and release of bDOC partly control NO3- export from forested catchments in New York State, USA. We examined whether DOC and NO3- are both driven by soil C processes that produce inverse coupling at the scale of soil cores as well as across catchments, through comparison of soil and surface water chemistry across nine catchments selected from long-term monitoring networks in the Catskill and Adirondack Mountains. In addition, we conducted a series of soil core leaching experiments to examine the role of acidification and recovery in driving the net production of DOC and NO3- from soils. Over 8 months, soil cores were leached biweekly with simulated rainfall solutions of varying pH (3.6 to 7.0) from additions of H2SO4, CaCO3 and NaOH. These experiments did not yield a pH-induced change in DOC quantity, but did show a change in DOC quality, in that acidified cores released more bio-available DOC with less depleted 13C-DOC than cores with experimentally increased pH. All cores leached substantial amounts of nitrate. Together, these lab- and field comparisons are being used to identify the role of soil production and consumption processes in driving cross-watershed differences in DOC and NO3- loss, or whether other factors (e.g., riparian, in-stream or hydrologic processes) likely explain this relationship.

Sampling depth confounds soil acidification outcomes

USDA-ARS?s Scientific Manuscript database

In the northern Great Plains (NGP) of North America, surface sampling depths of 0-15 or 0-20 cm are suggested for testing soil characteristics such as pH. However, acidification is often most pronounced near the soil surface. Thus, sampling deeper can potentially dilute (increase) pH measurements an...

Volcanic carbon dioxide vents show ecosystem effects of ocean acidification.

PubMed

Hall-Spencer, Jason M; Rodolfo-Metalpa, Riccardo; Martin, Sophie; Ransome, Emma; Fine, Maoz; Turner, Suzanne M; Rowley, Sonia J; Tedesco, Dario; Buia, Maria-Cristina

2008-07-03

The atmospheric partial pressure of carbon dioxide (p(CO(2))) will almost certainly be double that of pre-industrial levels by 2100 and will be considerably higher than at any time during the past few million years. The oceans are a principal sink for anthropogenic CO(2) where it is estimated to have caused a 30% increase in the concentration of H(+) in ocean surface waters since the early 1900s and may lead to a drop in seawater pH of up to 0.5 units by 2100 (refs 2, 3). Our understanding of how increased ocean acidity may affect marine ecosystems is at present very limited as almost all studies have been in vitro, short-term, rapid perturbation experiments on isolated elements of the ecosystem. Here we show the effects of acidification on benthic ecosystems at shallow coastal sites where volcanic CO(2) vents lower the pH of the water column. Along gradients of normal pH (8.1-8.2) to lowered pH (mean 7.8-7.9, minimum 7.4-7.5), typical rocky shore communities with abundant calcareous organisms shifted to communities lacking scleractinian corals with significant reductions in sea urchin and coralline algal abundance. To our knowledge, this is the first ecosystem-scale validation of predictions that these important groups of organisms are susceptible to elevated amounts of p(CO(2)). Sea-grass production was highest in an area at mean pH 7.6 (1,827 (mu)atm p(CO(2))) where coralline algal biomass was significantly reduced and gastropod shells were dissolving due to periods of carbonate sub-saturation. The species populating the vent sites comprise a suite of organisms that are resilient to naturally high concentrations of p(CO(2)) and indicate that ocean acidification may benefit highly invasive non-native algal species. Our results provide the first in situ insights into how shallow water marine communities might change when susceptible organisms are removed owing to ocean acidification.

Slowing Ocean Acidification

NASA Astrophysics Data System (ADS)

Bravo, A.

2016-12-01

Currently our ocean's pH is 8.1, a decrease from 8.2 in the past 200 years since the beginning of the industrial revolution. The ocean absorbs about a third of the carbon dioxide (CO2) from the atmosphere, which is helpful to us, since reducing the amount of CO2 in the atmosphere shows global warming. However, what is the impact of all that CO2 on the ocean? I evaluated the effect of acidic water on bivalves, and found that the shells were broken down with exposure to increased acidity. I am concerned that continued ocean acidification will impact organisms that are unable to adapt to the changing ocean chemistry. While the US currently invests in alternative forms of energy including solar and wind, approximately 66% of our energy comes from sources that are releasing CO2 into the atmosphere. I want to explore the potential of wave energy as another form of renewable energy. When wind blows over the surface of the ocean, it creates a wave. Could this wave energy be a consistent clean energy source? Could a strategy to slow and reverse ocean acidification be found in the ocean?

Comparison of Ecotoxicological Dose-Response Relationships between Amphibians (Lithobates sylvaticus and Ambystoma maculatum) and Fish (Salmo salar and Salvelinus fontinalis) in the Freshwater Acidification Literature

NASA Astrophysics Data System (ADS)

Maxwell, A.; Gooding Lassiter, M.; Greaver, T.

2016-12-01

Ecosystem acidification due to increased deposition of oxides of nitrogen (NOX) and sulfur (SOX) has been an issue since the 1970s. Elevated levels of NOX and SOX deposition due to human activity can cause chemical changes in terrestrial and freshwater ecosystems, which may adversely affect biota. Reduced pH is a chemical change that may be caused by elevated deposition; survival is an example of a biological response to chemical changes. Although amphibians have historically been considered relatively tolerant to acidification, most studies have focused on phytoplankton, invertebrates and fish. The goal of this study is to compare ecotoxicological dose-response relationships for amphibians and fish in the freshwater acidification literature from the 1970s to the present. Our data sources were references from the U.S. EPA's 2008 Integrated Science Assessment for Oxides of Nitrogen and Sulfur - Ecological Criteria, references from the Baker et al. 1990 report "Biological effects of changes in surface water acid-base chemistry", and keyword searches in Web of Science limited to 1990 to 2016 to include more recent studies. Fish comprised nearly 50% of the 54 identified species or groupings for which acidification effects are available, and amphibians comprised about 12% of them. Initial data suggest the most common dose-response relationship among commonly studied fish and amphibians was pH versus survival. Amphibians (Lithobates sylvaticus and Ambystoma maculatum) appear more tolerant to acidification than fish (Salmo salar and Salvelinus fontinalis). Although this observation is solely based on the pH versus survival dose-response relationships, other factors may also contribute to differences in tolerance to acidification between amphibians and fish. The views expressed in this abstract are those of the authors and do not necessarily represent the views or policies of the U.S. EPA.

An alternative model for CaCO3 over-shooting during the PETM: Biological carbonate compensation

NASA Astrophysics Data System (ADS)

Luo, Yiming; Boudreau, Bernard P.; Dickens, Gerald R.; Sluijs, Appy; Middelburg, Jack J.

2016-11-01

Decreased CaCO3 content of deep-sea sediments argues for rapid and massive acidification of the oceans during the Paleocene-Eocene Thermal Maximum (PETM, ∼56 Ma BP). In the course of the subsequent recovery from this acidification, sediment CaCO3 content came to exceed pre-PETM levels, known as over-shooting. Past studies have largely attributed the latter to increased alkalinity input to the oceans via enhanced weathering, but this ignores potentially important biological factors. We successfully reproduce the CaCO3 records from Walvis Ridge in the Atlantic Ocean, including over-shooting, using a biogeochemical box model. Replication of the CaCO3 records required: 1) introduction of a maximum of ∼6500 GtC of CO2 directly into deep-ocean waters or ∼8000 GtC into the atmosphere, 2) limited deep-water exchange between the Indo-Atlantic and Pacific oceans, 3) the disappearance of sediment bioturbation during a portion of the PETM, and 4) most central to this study, a ∼50% reduction in net CaCO3 production, during acidification. In our simulations, over-shooting is an emergent property, generated at constant alkalinity input (no weathering feedback) as a consequence of attenuated CaCO3 productivity. This occurs because lower net CaCO3 production from surface waters allows alkalinity to build-up in the deep oceans (alkalinization), thus promoting deep-water super-saturation. Restoration of CaCO3 productivity later in the PETM, particularly in the Indo-Atlantic Ocean, leads to greater accumulation of CaCO3, ergo over-shooting, which returns the ocean to pre-PETM conditions over a time scale greater than 200 ka.

Biogenic acidification reduces sea urchin gonad growth and increases susceptibility of aquaculture to ocean acidification.

PubMed

Mos, Benjamin; Byrne, Maria; Dworjanyn, Symon A

2016-02-01

Decreasing oceanic pH (ocean acidification) has emphasised the influence of carbonate chemistry on growth of calcifying marine organisms. However, calcifiers can also change carbonate chemistry of surrounding seawater through respiration and calcification, a potential limitation for aquaculture. This study examined how seawater exchange rate and stocking density of the sea urchin Tripneustes gratilla that were reproductively mature affected carbonate system parameters of their culture water, which in turn influenced growth, gonad production and gonad condition. Growth, relative spine length, gonad production and consumption rates were reduced by up to 67% by increased density (9-43 individuals.m(-2)) and reduced exchange rates (3.0-0.3 exchanges.hr(-1)), but survival and food conversion efficiency were unaffected. Analysis of the influence of seawater parameters indicated that reduced pH and calcite saturation state (ΩCa) were the primary factors limiting gonad production and growth. Uptake of bicarbonate and release of respiratory CO2 by T. gratilla changed the carbonate chemistry of surrounding water. Importantly total alkalinity (AT) was reduced, likely due to calcification by the urchins. Low AT limits the capacity of culture water to buffer against acidification. Direct management to counter biogenic acidification will be required to maintain productivity and reproductive output of marine calcifiers, especially as the ocean carbonate system is altered by climate driven ocean acidification. Copyright © 2015 Elsevier Ltd. All rights reserved.

Effects of ocean acidification on the early life history of a tropical marine fish.

PubMed

Munday, Philip L; Donelson, Jennifer M; Dixson, Danielle L; Endo, Geoff G K

2009-09-22

Little is known about how fishes and other non-calcifying marine organisms will respond to the increased levels of dissolved CO(2) and reduced sea water pH that are predicted to occur over the coming century. We reared eggs and larvae of the orange clownfish, Amphiprion percula, in sea water simulating a range of ocean acidification scenarios for the next 50-100 years (current day, 550, 750 and 1030 ppm atmospheric CO(2)). CO(2) acidification had no detectable effect on embryonic duration, egg survival and size at hatching. In contrast, CO(2) acidification tended to increase the growth rate of larvae. By the time of settlement (11 days post-hatching), larvae from some parental pairs were 15 to 18 per cent longer and 47 to 52 per cent heavier in acidified water compared with controls. Larvae from other parents were unaffected by CO(2) acidification. Elevated CO(2) and reduced pH had no effect on the maximum swimming speed of settlement-stage larvae. There was, however, a weak positive relationship between length and swimming speed. Large size is usually considered to be advantageous for larvae and newly settled juveniles. Consequently, these results suggest that levels of ocean acidification likely to be experienced in the near future might not, in isolation, significantly disadvantage the growth and performance of larvae from benthic-spawning marine fishes.

Effects of ocean acidification on the early life history of a tropical marine fish

PubMed Central

Munday, Philip L.; Donelson, Jennifer M.; Dixson, Danielle L.; Endo, Geoff G. K.

2009-01-01

Little is known about how fishes and other non-calcifying marine organisms will respond to the increased levels of dissolved CO2 and reduced sea water pH that are predicted to occur over the coming century. We reared eggs and larvae of the orange clownfish, Amphiprion percula, in sea water simulating a range of ocean acidification scenarios for the next 50–100 years (current day, 550, 750 and 1030 ppm atmospheric CO2). CO2 acidification had no detectable effect on embryonic duration, egg survival and size at hatching. In contrast, CO2 acidification tended to increase the growth rate of larvae. By the time of settlement (11 days post-hatching), larvae from some parental pairs were 15 to 18 per cent longer and 47 to 52 per cent heavier in acidified water compared with controls. Larvae from other parents were unaffected by CO2 acidification. Elevated CO2 and reduced pH had no effect on the maximum swimming speed of settlement-stage larvae. There was, however, a weak positive relationship between length and swimming speed. Large size is usually considered to be advantageous for larvae and newly settled juveniles. Consequently, these results suggest that levels of ocean acidification likely to be experienced in the near future might not, in isolation, significantly disadvantage the growth and performance of larvae from benthic-spawning marine fishes. PMID:19556256

Ocean acidification alters temperature and salinity preferences in larval fish.

PubMed

Pistevos, Jennifer C A; Nagelkerken, Ivan; Rossi, Tullio; Connell, Sean D

2017-02-01

Ocean acidification alters the way in which animals perceive and respond to their world by affecting a variety of senses such as audition, olfaction, vision and pH sensing. Marine species rely on other senses as well, but we know little of how these might be affected by ocean acidification. We tested whether ocean acidification can alter the preference for physicochemical cues used for dispersal between ocean and estuarine environments. We experimentally assessed the behavioural response of a larval fish (Lates calcarifer) to elevated temperature and reduced salinity, including estuarine water of multiple cues for detecting settlement habitat. Larval fish raised under elevated CO 2 concentrations were attracted by warmer water, but temperature had no effect on fish raised in contemporary CO 2 concentrations. In contrast, contemporary larvae were deterred by lower salinity water, where CO 2 -treated fish showed no such response. Natural estuarine water-of higher temperature, lower salinity, and containing estuarine olfactory cues-was only preferred by fish treated under forecasted high CO 2 conditions. We show for the first time that attraction by larval fish towards physicochemical cues can be altered by ocean acidification. Such alterations to perception and evaluation of environmental cues during the critical process of dispersal can potentially have implications for ensuing recruitment and population replenishment. Our study not only shows that freshwater species that spend part of their life cycle in the ocean might also be affected by ocean acidification, but that behavioural responses towards key physicochemical cues can also be negated through elevated CO 2 from human emissions.

Effects of ocean acidification on the ballast of surface aggregates sinking through the twilight zone.

PubMed

de Jesus Mendes, Pedro A; Thomsen, Laurenz

2012-01-01

The dissolution of CaCO(3) is one of the ways ocean acidification can, potentially, greatly affect the ballast of aggregates. A diminution of the ballast could reduce the settling speed of aggregates, resulting in a change in the carbon flux to the deep sea. This would mean lower amounts of more refractory organic matter reaching the ocean floor. This work aimed to determine the effect of ocean acidification on the ballast of sinking surface aggregates. Our hypothesis was that the decrease of pH will increase the dissolution of particulate inorganic carbon ballasting the aggregates, consequently reducing their settling velocity and increasing their residence time in the upper twilight zone. Using a new methodology for simulation of aggregate settling, our results suggest that future pCO(2) conditions can significantly change the ballast composition of sinking aggregates. The change in aggregate composition had an effect on the size distribution of the aggregates, with a shift to smaller aggregates. A change also occurred in the settling velocity of the particles, which would lead to a higher residence time in the water column, where they could be continuously degraded. In the environment, such an effect would result in a reduction of the carbon flux to the deep-sea. This reduction would impact those benthic communities, which rely on the vertical flow of carbon as primary source of energy.

Acidification mediated by a river plume and coastal upwelling on a fringing reef at the east coast of Hainan Island, Northern South China Sea

NASA Astrophysics Data System (ADS)

Dong, Xu; Huang, Haining; Zheng, Nan; Pan, Aijun; Wang, Sumin; Huo, Cheng; Zhou, Kaiwen; Lin, Hui; Ji, Weidong

2017-09-01

We investigated the dynamics of carbonate system which was greatly modulated by a river plume and coastal upwelling in July 2014 and July 2015 at the east coast of Hainan Island where a fringing reef distributes inshore. By using a three end-member mixing model, we semiquantitatively estimated the removal of dissolved inorganic carbon (DIC) mediated by biological production in the river plume and upwelled water to be 13 ± 17 and 15 ± 16 μmol kg-1, respectively. The enhanced organic production was mainly responsible for these DIC consumptions in both two regimes, however, nearly a half of DIC removal was attributed to biocalcification in the plume system while it was negligible in the upwelling system. Furthermore, the modeled results over reefs revealed that river plume and coastal upwelling were two major threats of acidification to coral communities at the east coast of Hainan Island during cruises. In comparison, the biological contribution to acidification was limited for balancing between organic production and biocalcification during July 2014 cruise, whereas the acidification was greatly intensified by organic degradation during July 2015 cruise. It was verified that naturally local acidification (physical and biological processes) played a major role in great pH decreases on a short-term scale, leading to coastal waters more vulnerable to anthropogenic "ocean acidification" (uptake of atmospheric CO2) by reducing buffering capacity of waters. Finally, effects of acidification associated with other local threats on a fringing reef were further depicted with a conceptual model.

Liming Influences Growth and Nutrient Balances in Sugar Maple (Acer saccharum) Seedlings on an Acidic Forest Soil

Treesearch

Dudley J. Raynal

1998-01-01

Forests in the northeastern US have been limed to mitigate soil acidification and the acidity of surface waters and to improve soil base cation status. Much of the area considered for liming is within the range of sugar maple (Acer saccharum), but there is a poor understanding of how liming influences growth and nutrient balance of this species on...

Synergistic effects of climate-related variables suggest future physiological impairment in a top oceanic predator.

PubMed

Rosa, Rui; Seibel, Brad A

2008-12-30

By the end of this century, anthropogenic carbon dioxide (CO(2)) emissions are expected to decrease the surface ocean pH by as much as 0.3 unit. At the same time, the ocean is expected to warm with an associated expansion of the oxygen minimum layer (OML). Thus, there is a growing demand to understand the response of the marine biota to these global changes. We show that ocean acidification will substantially depress metabolic rates (31%) and activity levels (45%) in the jumbo squid, Dosidicus gigas, a top predator in the Eastern Pacific. This effect is exacerbated by high temperature. Reduced aerobic and locomotory scope in warm, high-CO(2) surface waters will presumably impair predator-prey interactions with cascading consequences for growth, reproduction, and survival. Moreover, as the OML shoals, squids will have to retreat to these shallower, less hospitable, waters at night to feed and repay any oxygen debt that accumulates during their diel vertical migration into the OML. Thus, we demonstrate that, in the absence of adaptation or horizontal migration, the synergism between ocean acidification, global warming, and expanding hypoxia will compress the habitable depth range of the species. These interactions may ultimately define the long-term fate of this commercially and ecologically important predator.

Synergistic effects of climate-related variables suggest future physiological impairment in a top oceanic predator

PubMed Central

Rosa, Rui; Seibel, Brad A.

2008-01-01

By the end of this century, anthropogenic carbon dioxide (CO2) emissions are expected to decrease the surface ocean pH by as much as 0.3 unit. At the same time, the ocean is expected to warm with an associated expansion of the oxygen minimum layer (OML). Thus, there is a growing demand to understand the response of the marine biota to these global changes. We show that ocean acidification will substantially depress metabolic rates (31%) and activity levels (45%) in the jumbo squid, Dosidicus gigas, a top predator in the Eastern Pacific. This effect is exacerbated by high temperature. Reduced aerobic and locomotory scope in warm, high-CO2 surface waters will presumably impair predator–prey interactions with cascading consequences for growth, reproduction, and survival. Moreover, as the OML shoals, squids will have to retreat to these shallower, less hospitable, waters at night to feed and repay any oxygen debt that accumulates during their diel vertical migration into the OML. Thus, we demonstrate that, in the absence of adaptation or horizontal migration, the synergism between ocean acidification, global warming, and expanding hypoxia will compress the habitable depth range of the species. These interactions may ultimately define the long-term fate of this commercially and ecologically important predator. PMID:19075232

Calcification persists with CO2-induced ocean acidification but decreases with warming for the Caribbean coral Siderastrea siderea

NASA Astrophysics Data System (ADS)

Castillo, K. D.; Ries, J. B.; Westfield, I. T.; Weiss, J. M.; Bruno, J. F.

2012-12-01

Atmospheric carbon dioxide (pCO2) induced ocean acidification and rising seawater temperatures are identified as two of the greatest threats to modern coral reefs. Within this century, surface seawater pH is expected to decrease by at least 0.3 units, and sea surface temperature is predicted to rise by 1 to 3 °C. However, uncertainty remains as to whether ocean acidification or ocean warming will have a more deleterious impact on coral reefs by the end of the century. Here, we present results of 95-day laboratory experiments in which we investigated the impact of CO2-induced ocean acidification and temperature on the calcification rate of the tropical reef-building zooxanthellate scleractinian coral Siderastrea siderea. We found that calcification rates for S. siderea, estimated from buoyant weighing, increased as pCO2 increased from a pre-industrial value of 324 ppm to a near-present-day value of 477 ppm, remained unchanged as pCO2 increased from 477 ppm to the predicted end-of-century value of 604 ppm, and only declined at 6-times the modern pCO2 value of 2553 ppm. Corals reared at average pCO2 of 488 ppm and at temperatures of 25 and 32 °C, approximately the lower and upper temperature extremes for this species, calcified at lower rates relative to corals reared at 28 °C under equivalent pCO2. These results support the existing evidence that scleractinian corals such as S. siderea are able to manipulate the carbonate chemistry at their calcification site, enabling them to maintain their calcification rates under elevated pCO2 levels predicted for the end of this century. However, exposure of S. siderea corals to sea surface temperatures predicted for tropical waters for the end of this century grossly impaired their rate of calcification. These findings suggest that ocean warming poses a more immediate threat to the coral S. siderea than does ocean acidification, at least under scenarios (B1, A1T, and B2) predicted by the Intergovernmental Panel on Climate Change for the end of the 21st century. We are presently investigating the calcification responses of S. siderea to the combined effects of ocean acidification and warming, in order to better constrain how corals will respond to global CO2-induced changes that are predicted for the near future.

Risk maps for Antarctic krill under projected Southern Ocean acidification

NASA Astrophysics Data System (ADS)

Kawaguchi, S.; Ishida, A.; King, R.; Raymond, B.; Waller, N.; Constable, A.; Nicol, S.; Wakita, M.; Ishimatsu, A.

2013-09-01

Marine ecosystems of the Southern Ocean are particularly vulnerable to ocean acidification. Antarctic krill (Euphausia superba; hereafter krill) is the key pelagic species of the region and its largest fishery resource. There is therefore concern about the combined effects of climate change, ocean acidification and an expanding fishery on krill and ultimately, their dependent predators--whales, seals and penguins. However, little is known about the sensitivity of krill to ocean acidification. Juvenile and adult krill are already exposed to variable seawater carbonate chemistry because they occupy a range of habitats and migrate both vertically and horizontally on a daily and seasonal basis. Moreover, krill eggs sink from the surface to hatch at 700-1,000m (ref. ), where the carbon dioxide partial pressure (pCO2) in sea water is already greater than it is in the atmosphere. Krill eggs sink passively and so cannot avoid these conditions. Here we describe the sensitivity of krill egg hatch rates to increased CO2, and present a circumpolar risk map of krill hatching success under projected pCO2 levels. We find that important krill habitats of the Weddell Sea and the Haakon VII Sea to the east are likely to become high-risk areas for krill recruitment within a century. Furthermore, unless CO2 emissions are mitigated, the Southern Ocean krill population could collapse by 2300 with dire consequences for the entire ecosystem.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fimreite, N.; Nenseter, B.; Steen, B.

Over several decades severe acidification of streams and lakes has taken place in Scandinavia and North America, with catastrophic consequences for aquatic life. In certain water systems in southern Norway fish populations have been completely eliminated by severe acidification. This fish mortality has been attributed largely to increased concentrations of toxic aluminum and, since liming counteracts acidification and reduces the aluminum levels in the water, it has become the most widespread remedy to restore fish habitats. Cadmium concentrations in the water are also pH-dependent and, therefore, affected by liming. This laboratory experiment was conducted to clarify the significance of limingmore » as a factor in reducing cadmium concentrations from lake water and the behavior of cdamium following reacidification. In addition the behavior of organic materials under varying pH conditions was studied. 16 refs., 4 figs., 2 tabs.« less

The effect of harvest intensity on long-term calcium dynamics in soil and soil solution at three coniferous sites in Sweden

NASA Astrophysics Data System (ADS)

Zetterberg, Therese; Olsson, Bengt; Löfgren, Stefan; von Brömssen, Claudia; Brandtberg, Per-Olov

2013-04-01

Bioenergy from forests is a mean to reduce fossil fuel related carbon dioxide (CO2) emissions. The potential to replace fossil fuel with logging residues is large in countries with extensive forest resources such as Sweden where the supply of bioenergy to district heating plants has quintupled since the 1990's, now accounting for 46% of the total energy supply. However, the loss of nutrients and other elements in biomass is higher following harvest for bioenergy purposes (whole-tree harvest, WTH) compared with traditional clear-cutting (conventional harvest, CH). Calcium (Ca2+) is an important base cation, which buffer soils and surface water against acidification. The loss of Ca2+ and other base cations via harvest for bioenergy could therefore result in soil acidification and there is a growing concern in Sweden that the depletion in base cation pools would also lead to surface water acidification associated with lower base cation concentrations in runoff (Swedish Environmental Protection Agency, 2007). Furthermore, WTH may also prevent or delay a recovery from acidification in areas such as the southwestern parts of Sweden, where the pools of exchangeable cations have been substantially depleted as a result of historically high sulfate (SO42-) deposition. In this paper, long-term treatment differences in soil exchangeable Ca2+ pools (down to 20 cm) and soil solution Ca2+ concentrations at 50 cm soil depth were examined at three coniferous sites in Sweden following CH and WTH in 1974-76. The results showed that soil water concentrations of Ca2+were -17 μeq l-1 (or 40%) lower in WTH plots compared with CH plots, 27-30 years after harvest. The main treatment differences had largely disappeared 32 to 35 years after harvest although site specific treatment differences (ΔWTH-CH: -24 μeq l-1) were still measurable at the well-buffered site in northern Sweden. These results are in agreement with soil data showing that previously found treatment differences in Ca2+ pools had diminished in the forest floor but remained in deeper soil layers (-0.29, -0.37 and -0.24 kmolc ha-1 in the 5-10, 10-15 and 15-20 cm soil layer, respectively). The effects on soil Ca2+ pools appeared to be most pronounced at the well-buffered northern site. These results indicate that the effect of WTH on soil and soil solution concentrations is temporary but site specific. Contrary to common beliefs, the greatest effects were observed at the well-buffered site where the loss of Ca2+ during WTH is less likely to lead to acidification effects. The treatment effects on soil solution at the more acidic sites in southern Sweden were much smaller and probably not large enough to fully counterbalance the general recovery from acidification during the study period. References Swedish Environmental Protection Agency, 2007. Bara naturlig försurning. Bilagor till underlagsrapport till fördjupad utvärdering av miljömålen. Rapport 5780. 208 pp. In Swedish.

Evidence for ocean acidification in the Great Barrier Reef of Australia

NASA Astrophysics Data System (ADS)

Wei, Gangjian; McCulloch, Malcolm T.; Mortimer, Graham; Deng, Wengfeng; Xie, Luhua

2009-04-01

Geochemical records preserved in the long-lived carbonate skeleton of corals provide one of the few means to reconstruct changes in seawater pH since the commencement of the industrial era. This information is important in not only determining the response of the surface oceans to ocean acidification from enhanced uptake of CO 2, but also to better understand the effects of ocean acidification on carbonate secreting organisms such as corals, whose ability to calcify is highly pH dependent. Here we report an ˜200 year δ 11B isotopic record, extracted from a long-lived Porites coral from the central Great Barrier Reef of Australia. This record covering the period from 1800 to 2004 was sampled at yearly increments from 1940 to the present and 5-year increments prior to 1940. The δ 11B isotopic compositions reflect variations in seawater pH, and the δ 13C changes in the carbon composition of surface water due to fossil fuel burning over this period. In addition complementary Ba/Ca, δ 18O and Mg/Ca data was obtained providing proxies for terrestrial runoff, salinity and temperature changes over the past 200 years in this region. Positive thermal ionization mass spectrometry (PTIMS) method was utilized in order to enable the highest precision and most accurate measurements of δ 11B values. The internal precision and reproducibility for δ 11B of our measurements are better than ±0.2‰ (2 σ), which translates to a precision of better than ±0.02 pH units. Our results indicate that the long-term pre-industrial variation of seawater pH in this region is partially related to the decadal-interdecadal variability of atmospheric and oceanic anomalies in the Pacific. In the periods around 1940 and 1998 there are also rapid oscillations in δ 11B compositions equivalent changes in pH of almost 0.5 U. The 1998 oscillation is co-incident with a major coral bleaching event indicating the sensitivity of skeletal δ 11B compositions to loss of zooxanthellate symbionts. Importantly, from the 1940s to the present-day, there is a general overall trend of ocean acidification with pH decreasing by about 0.2-0.3 U, the range being dependent on the value assumed for the fractionation factor α(B3-B4) of the boric acid and borate species in seawater. Correlations of δ 11B with δ 13C during this interval indicate that the increasing trend towards ocean acidification over the past 60 years in this region is the result of enhanced dissolution of CO 2 in surface waters from the rapidly increasing levels of atmospheric CO 2, mainly from fossil fuel burning. This suggests that the increased levels of anthropogenic CO 2 in atmosphere has already caused a significant trend towards acidification in the oceans during the past decades. Observations of surprisingly large decreases in pH across important carbonate producing regions, such as the Great Barrier Reef of Australia, raise serious concerns about the impact of Greenhouse gas emissions on coral calcification.

Shallow water submarine hydrothermal activity - A case study in the assessment of ocean acidification and fertilization

NASA Astrophysics Data System (ADS)

Zhang, J.; Yoshida, K.; Hagiwara, T.; Nagao, K.; Kusakabe, M.; Wang, B.; Chen, C. A.

2012-12-01

Most natural Shallow Water submarine Hydrothermal activates (SWH) along coastlines are related to hydrothermal eruptions involving heating of groundwater with the volcanic gas. These SWHs supply nutrients such as phosphorus and micro nutrients like iron to the euphotic zone, contributing to the overall natural fertility and primary productivity of coastal waters. However, SWHs also have a negative effect, dispersing toxic materials such as mercury and arsenic, and affecting the acidification of the surrounding waters. In this study, we evaluate the impact of "iron supply" and "ocean acidification" on the primary production in a coastal marine environment, at a SWH area discovered off Gueshandao Island, northeast Taiwan. In the past three years, expeditions were conducted and observations made around this SWH site. Divers, small boats and a research vessel (R/V OR1, Ocean University National Taiwan) were used to survey successively larger areas around the site. Some of the results obtained are as follows. Hydrothermal vents are located in a hilly terrain rich with hot spring water with gas erupting intermittently. There are two types of vents, roughly divided by color, yellow hot spring water with higher temperature >110 degC ejected from sulfur chimneys of various sizes, and colorless water with lower temperature ~80 degC ejected directly from the crevices of the andesitic bedrock. Natural sulfur solidifying in the mouth of a small chimney was captured by a video camera, and explosions were also observed at intervals of a few minutes. Sediment, sand and particles of sulfur were deposited on the sides to a radius of about 50 m condensing around the chimney. The bottom type changes from sand/particles to outcrop/rock away from the vents. Moreover, gas samples were collected from the vents; the ratios of gas concentrations (N2/Ar) and isotopic composition of noble gas (3He/4He) suggest that these volcanic gases are mantle-derived. Hydrothermal fluid with high pH values between 2.1 ~ 3.5 erupts from the vents, and diffuses toward the ocean surface affecting water up to 1 km way. The high pCO2 in the surface seawater is widely distributed, and the low pH value is also observed widely in mid-depth water (5 ~ 15 m). Water samples collected around the SHW site show higher concentrations of nutrients Si and P, and typically higher micro nutrients Mn, and even Fe as compared to normal seawater. Chlorophyll a in particular shows high values of several tens to hundreds times greater than normal subtropical seawater. We find for the first time in the nature, that SHW enhances the growth of phytoplankton, and contributes to primary productivity of the surrounding waters.

Distributions and Changes of Carbonate Parameters Along the U.S. East Coast

NASA Astrophysics Data System (ADS)

Xu, Y. Y.; Cai, W. J.; Wanninkhof, R. H.; Salisbury, J., II

2017-12-01

On top of anthropogenic climate change, upwelling, eutrophication, river discharge, and interactions with the open ocean have affected carbonate chemistry in coastal waters. In this study, we present the large-scale variations of carbonate parameters along the U.S. east coast using in situ observations obtained during an East Coast Ocean Acidification (ECOA) cruise in summer 2015. Compare with previous large-scale cruises along the east coast, the ECOA cruise increases spatial coverage in the Gulf of Marine region and has more offshore stations for a better understanding of carbon dynamics in coastal waters and their interactions with open ocean waters. Our results show that the spatial distribution of water mass properties set up the large-scale advection of salt and heat and the distribution of total alkalinity (TA). However, dissolved inorganic carbon (DIC) shows a distinct pattern. Coastal water pH displays high variability in the Gulf of Maine and the Mid-Atlantic Bight (MAB). But it is relatively homogeneous in the South Atlantic Bight (SAB). In contrast, the distribution of aragonite saturation state (Ω) has an increase pattern from north to south similar to those of TA, SST, and SSS. A mechanistic discussion will be presented to understand the controls on Ω in eastern coastal waters. A comparison with previous cruises also suggests very different changes of pH and Ω in the MAB and SAB. Preliminary analysis suggests an overall increase in surface pH and Ω in the MAB. In contrast, pH and Ω in the SAB surface waters decrease over the past two decades. This work serves as a platform for the monitoring of large-scale carbon cycling in the U.S. east coast. It is also important to identify the physical and biogeochemical processes that affect these distributions and changes over time for a better understanding of carbon cycling and ocean acidification in coastal waters.

Deciphering ocean acidification from eutrophication events as the main cause of neritic carbonate factory collapse: Insight from a recurrently-perturbed Earth (Lower Jurassic, Morocco)

NASA Astrophysics Data System (ADS)

Bodin, S.; Krencker, F.; Suan, G.; Heimhofer, U.; Immenhauser, A.

2013-12-01

Shallow-marine carbonate ecosystems react sensitively to environmental changes and have often been documented as being early responders to climatic deteriorations. In extreme cases, such as pronounced global warming, ocean eutrophication or acidification events, the shallow-water carbonate community can collapse, leading to the so-called drowning events. However, deciphering the exact cause of carbonate platform demise in the geological record is not straightforward as the aforementioned mechanisms are intimately linked via feedback processes. The Upper Pliensbachian-Toarcian of Morocco presents an exceptional case study with regard to this question for several reasons: (1) It offers outstanding outcrops of carbonate ecosystem, that can be traced from shallow- to deep-water settings. (2) Over a period of ca. 15 Myrs, the Western Tethyan area was submitted to recurrent extreme environmental changes, linked to the long-lasting activity of the Karoo-Ferrar Large Igneous Province (LIP). During this period, the planet Earth has experienced several rapid changes between coldhouse and hothouse state, accompanied by massive injection of carbon into the ocean/atmosphere reservoirs. (3) The magnitude of change differs however from one event to another, with an oceanic acidification event only likely to have happened at the onset of the Toarcian Oceanic Anoxic Event (T-OAE), but not for the other events. In the High Atlas Basin of Morocco, a total of four successive events of carbonate factory demise can be documented during the Late Pliensbachian - Toarcian time interval. These events are contemporaneous with marine extinction events and can be linked to environmental deterioration consecutive to pulsed activity of the Karoo-Ferrar LIP. They all lead to a shutdown of carbonate accumulation. They however differ in their timing and unfolding. Of major interest are the demise events recorded at the Pliensbachian-Toarcian boundary (eT-E) and at the onset of the T-OAE. An intense sea-water eutrophication occurs during the first event, as documented by phosphorus analyses in deep-water setting and the disappearance of shallow-water oligotrophic hypercalcifiers (corals & lithiotids bivalves) to the benefit of siliciclastic sedimentation. Interestingly, the transition between the two sedimentation regimes is characterized by a swarming of echinoids. The oligotrophic hypercalcifiers are however quickly reappearing in the aftermath of the eT-e. The second demise event, associated with the T-OAE, where an ocean acidification event is suspected, is characterized by a dissolution surface and the long-lasting disappearance of the hypercalcifiers organisms. A clear differentiation is therefore documented between neritic carbonate factory demise linked to seawater eutrophication from those linked to ocean acidification.

A new mechanism for calcium loss in forest-floor soils

USGS Publications Warehouse

Lawrence, G.B.; David, M.B.; Shortle, W.C.

1995-01-01

CALCIUM is the fifth most abundant element in trees, and is an essential component for wood formation and the maintenance of cell walls. Depletion of Ca from the rooting zone can result in acidification of soil1 and surface water2 and possibly growth decline and dieback of red spruce3,4. During the past six decades, concentrations of root-available Ca (exchangeable and acid-ex tract able forms) in forest-floor soils have decreased in the northeastern United States5,6. Both net forest growth and acid deposition have been put forth as mechanisms that can account for this Ca depletion5,6. Here, however, we present data collected in red spruce forests in the northeastern United States that are inconsistent with either of these mechanisms. We propose that aluminium, mobilized in the mineral soil by acid deposition, is transported into the forest floor in a reactive form that reduces storage of Ca, and thus its availability for root uptake. This results in potential stress to trees and, by increasing the demand for Ca, also decreases neutralization of drainage waters, thereby leading to acidification of lakes and streams.

Broken Chains: The Effect of Ocean Acidification on Bivalve and Echinoid Development

NASA Astrophysics Data System (ADS)

Richardson, K.

2016-12-01

Global warming is one of the most urgent issues facing the interconnected systems of our planet. One important impact of global warming is ocean acidification, which is a change in the pH of the oceans due to increased levels of carbon dioxide in the atmosphere. This can harm ocean life in many ways, including the disintegration of reef structures and the weakening of many types of sea animals' shells. The purpose of this project is to assess the efficacy of a novel method of raising the pH of increasingly acidic ocean waters. The experiment was set up with water of varying pH levels. There were three different experiment groups, including current ocean water (pH 8.1), increased acidity ocean water (pH 7.5), and an increased acidity ocean water with an activated carbon filter (pH 7.5). Six bivalve shells were placed in each solution . Mass loss data was taken from bivalve shells every three days over the course of thirty days (for a total of ten measurements). I hypothesized that the carbon filter would improve the pH of the ocean water (by raising the pH from 7.5) to that of normal ocean water (pH 8.1). The data showed that while the acidic ocean water shell's weight decreased (by 13%), the acidic water with the filter and current ocean water decreased by 0.3% and 0.5%, respectively. Overall, the activated carbon filter decreased the amount of weight change from the acidic water. The data is applicable to helping solve ocean acidification - activated charcoal greatly improved the effects of very acidic ocean water, which could be used in the future to help offset the impact of ocean acidification on its creatures.

Increases in dissolved organic carbon accelerate loss of toxic Al in Adirondack lakes recovering from acidification

USGS Publications Warehouse

Lawrence, Gregory B.; Dukett, James E; Houck, Nathan; Snyder, Phillip; Capone, Susan B.

2013-01-01

Increasing pH and decreasing Al in surface waters recovering from acidification have been accompanied by increasing concentrations of dissolved organic carbon (DOC) and associated organic acids that partially offset pH increases and complicate assessments of recovery from acidification. To better understand the processes of recovery, monthly chemistry from 42 lakes in the Adirondack region, NY, collected from 1994 to 2011, were used to (1) evaluate long-term changes in DOC and associated strongly acidic organic acids and (2) use the base-cation surplus (BCS) as a chemical index to assess the effects of increasing DOC concentrations on the Al chemistry of these lakes. Over the study period, the BCS increased (p < 0.01) and concentrations of toxic inorganic monomeric Al (IMAl) decreased (p < 0.01). The decreases in IMAl were greater than expected from the increases in the BCS. Higher DOC concentrations that increased organic complexation of Al resulted in a decrease in the IMAl fraction of total monomeric Al from 57% in 1994 to 23% in 2011. Increasing DOC concentrations have accelerated recovery in terms of decreasing toxic Al beyond that directly accomplished by reducing atmospheric deposition of strong mineral acids.

Ocean acidification causes structural deformities in juvenile coral skeletons.

PubMed

Foster, Taryn; Falter, James L; McCulloch, Malcolm T; Clode, Peta L

2016-02-01

Rising atmospheric CO2 is causing the oceans to both warm and acidify, which could reduce the calcification rates of corals globally. Successful coral recruitment and high rates of juvenile calcification are critical to the replenishment and ultimate viability of coral reef ecosystems. Although elevated Pco2 (partial pressure of CO2) has been shown to reduce the skeletal weight of coral recruits, the structural changes caused by acidification during initial skeletal deposition are unknown. We show, using high-resolution three-dimensional x-ray microscopy, that ocean acidification (Pco2 ~900 μatm, pH ~7.7) not only causes reduced overall mineral deposition but also a deformed and porous skeletal structure in newly settled coral recruits. In contrast, elevated temperature (+3°C) had little effect on skeletal formation except to partially mitigate the effects of elevated Pco2. The striking structural deformities we observed show that new recruits are at significant risk, being unable to effectively build their skeletons in the Pco2 conditions predicted to occur for open ocean surface waters under a "business-as-usual" emissions scenario [RCP (representative concentration pathway) 8.5] by the year 2100.

Increases in dissolved organic carbon accelerate loss of toxic Al in Adirondack lakes recovering from acidification.

PubMed

Lawrence, Gregory B; Dukett, James E; Houck, Nathan; Snyder, Phil; Capone, Sue

2013-07-02

Increasing pH and decreasing Al in surface waters recovering from acidification have been accompanied by increasing concentrations of dissolved organic carbon (DOC) and associated organic acids that partially offset pH increases and complicate assessments of recovery from acidification. To better understand the processes of recovery, monthly chemistry from 42 lakes in the Adirondack region, NY, collected from 1994 to 2011, were used to (1) evaluate long-term changes in DOC and associated strongly acidic organic acids and (2) use the base-cation surplus (BCS) as a chemical index to assess the effects of increasing DOC concentrations on the Al chemistry of these lakes. Over the study period, the BCS increased (p < 0.01) and concentrations of toxic inorganic monomeric Al (IMAl) decreased (p < 0.01). The decreases in IMAl were greater than expected from the increases in the BCS. Higher DOC concentrations that increased organic complexation of Al resulted in a decrease in the IMAl fraction of total monomeric Al from 57% in 1994 to 23% in 2011. Increasing DOC concentrations have accelerated recovery in terms of decreasing toxic Al beyond that directly accomplished by reducing atmospheric deposition of strong mineral acids.

Ocean acidification causes structural deformities in juvenile coral skeletons

PubMed Central

Foster, Taryn; Falter, James L.; McCulloch, Malcolm T.; Clode, Peta L.

2016-01-01

Rising atmospheric CO2 is causing the oceans to both warm and acidify, which could reduce the calcification rates of corals globally. Successful coral recruitment and high rates of juvenile calcification are critical to the replenishment and ultimate viability of coral reef ecosystems. Although elevated Pco2 (partial pressure of CO2) has been shown to reduce the skeletal weight of coral recruits, the structural changes caused by acidification during initial skeletal deposition are unknown. We show, using high-resolution three-dimensional x-ray microscopy, that ocean acidification (Pco2 ~900 μatm, pH ~7.7) not only causes reduced overall mineral deposition but also a deformed and porous skeletal structure in newly settled coral recruits. In contrast, elevated temperature (+3°C) had little effect on skeletal formation except to partially mitigate the effects of elevated Pco2. The striking structural deformities we observed show that new recruits are at significant risk, being unable to effectively build their skeletons in the Pco2 conditions predicted to occur for open ocean surface waters under a “business-as-usual” emissions scenario [RCP (representative concentration pathway) 8.5] by the year 2100. PMID:26989776

Elevated carbon dioxide alters the plasma composition and behaviour of a shark

PubMed Central

Green, Leon; Jutfelt, Fredrik

2014-01-01

Increased carbon emissions from fossil fuels are increasing the pCO2 of the ocean surface waters in a process called ocean acidification. Elevated water pCO2 can induce physiological and behavioural effects in teleost fishes, although there appear to be large differences in sensitivity between species. There is currently no information available on the possible responses to future ocean acidification in elasmobranch fishes. We exposed small-spotted catsharks (Scyliorhinus canicula) to either control conditions or a year 2100 scenario of 990 μatm pCO2 for four weeks. We did not detect treatment effects on growth, resting metabolic rate, aerobic scope, skin denticle ultrastructure or skin denticle morphology. However, we found that the elevated pCO2 group buffered internal acidosis via accumulation with an associated increase in Na+, indicating that the blood chemistry remained altered despite the long acclimation period. The elevated pCO2 group also exhibited a shift in their nocturnal swimming pattern from a pattern of many starts and stops to more continuous swimming. Although CO2-exposed teleost fishes can display reduced behavioural asymmetry (lateralization), the CO2-exposed sharks showed increased lateralization. These behavioural effects may suggest that elasmobranch neurophysiology is affected by CO2, as in some teleosts, or that the sharks detect CO2 as a constant stressor, which leads to altered behaviour. The potential direct effects of ocean acidification should henceforth be considered when assessing future anthropogenic effects on sharks. PMID:25232027

Could artificial ocean alkalinization protect tropical coral ecosystems from ocean acidification?

NASA Astrophysics Data System (ADS)

Feng, Ellias Y.; Keller, David P.; Koeve, Wolfgang; Oschlies, Andreas

2016-07-01

Artificial ocean alkalinization (AOA) is investigated as a method to mitigate local ocean acidification and protect tropical coral ecosystems during a 21st century high CO2 emission scenario. Employing an Earth system model of intermediate complexity, our implementation of AOA in the Great Barrier Reef, Caribbean Sea and South China Sea regions, shows that alkalinization has the potential to counteract expected 21st century local acidification in regard to both oceanic surface aragonite saturation Ω and surface pCO2. Beyond preventing local acidification, regional AOA, however, results in locally elevated aragonite oversaturation and pCO2 decline. A notable consequence of stopping regional AOA is a rapid shift back to the acidified conditions of the target regions. We conclude that AOA may be a method that could help to keep regional coral ecosystems within saturation states and pCO2 values close to present-day values even in a high-emission scenario and thereby might ‘buy some time’ against the ocean acidification threat, even though regional AOA does not significantly mitigate the warming threat.

Incorporation of water-in-oil-in-water (W1/O/W2) double emulsion in a set-type yogurt model.

PubMed

Lalou, Sofia; Kadri, Hani El; Gkatzionis, Konstantinos

2017-10-01

The effect of W 1 /O/W 2 emulsion incorporation in set-type yogurt on the acidification process, physicochemical properties, bacterial growth kinetics and structural characteristics was investigated. The W 1 /O/W 2 emulsion was formed by using a two-step homogenisation process and milk as the W 1 and W 2 phases, and stability was monitored with optical microscopy and cryo-SEM. Adding the W 1 /O/W 2 emulsions reduced the acidification rate, viscosity and water retention capacity. Texture (adhesiveness, cohesiveness, hardness, and gumminess) differed in yogurts containing W 1 /O/W 2 emulsion compared to controls during the acidification process, however, trends became stable during storage. The growth of S. thermophilus during the acidification process of yogurt was reduced in the presence of W 1 /O/W 2 emulsion while L. bulgaricus trended higher during storage. This study shows that yogurts containing W 1 /O/W 2 emulsion are feasible subject to processing modification. Copyright © 2017 Elsevier Ltd. All rights reserved.

CO2-induced ocean acidification does not affect individual or group behaviour in a temperate damselfish.

PubMed

Kwan, Garfield Tsz; Hamilton, Trevor James; Tresguerres, Martin

2017-07-01

Open ocean surface CO 2 levels are projected to reach approximately 800 µatm, and ocean pH to decrease by approximately 0.3 units by the year 2100 due to anthropogenic CO 2 emissions and the subsequent process of ocean acidification (OA). When exposed to these CO 2 /pH values, several fish species display abnormal behaviour in laboratory tests, an effect proposed to be linked to altered neuronal GABA A- receptor function. Juvenile blacksmith ( Chromis punctipinnis ) are social fish that regularly experience CO 2 /pH fluctuations through kelp forest diurnal primary production and upwelling events, so we hypothesized that they might be resilient to OA. Blacksmiths were exposed to control conditions (pH ∼ 7.92; p CO 2  ∼ 540 µatm), constant acidification (pH ∼ 7.71; p CO 2  ∼ 921 µatm) and oscillating acidification (pH ∼ 7.91, p CO 2  ∼ 560 µatm (day), pH ∼ 7.70, p CO 2  ∼ 955 µatm (night)), and caught and tested in two seasons of the year when the ocean temperature was different: winter (16.5 ± 0.1°C) and summer (23.1 ± 0.1°C). Neither constant nor oscillating CO 2 -induced acidification affected blacksmith individual light/dark preference, inter-individual distance in a shoal or the shoal's response to a novel object, suggesting that blacksmiths are tolerant to projected future OA conditions. However, blacksmiths tested during the winter demonstrated significantly higher dark preference in the individual light/dark preference test, thus confirming season and/or water temperature as relevant factors to consider in behavioural tests.

Ocean acidification and warming will lower coral reef resilience

PubMed Central

Anthony, Kenneth R N; Maynard, Jeffrey A; Diaz-Pulido, Guillermo; Mumby, Peter J; Marshall, Paul A; Cao, Long; Hoegh-Guldberg, Ove

2011-01-01

Ocean warming and acidification from increasing levels of atmospheric CO2 represent major global threats to coral reefs, and are in many regions exacerbated by local-scale disturbances such as overfishing and nutrient enrichment. Our understanding of global threats and local-scale disturbances on reefs is growing, but their relative contribution to reef resilience and vulnerability in the future is unclear. Here, we analyse quantitatively how different combinations of CO2 and fishing pressure on herbivores will affect the ecological resilience of a simplified benthic reef community, as defined by its capacity to maintain and recover to coral-dominated states. We use a dynamic community model integrated with the growth and mortality responses for branching corals (Acropora) and fleshy macroalgae (Lobophora). We operationalize the resilience framework by parameterizing the response function for coral growth (calcification) by ocean acidification and warming, coral bleaching and mortality by warming, macroalgal mortality by herbivore grazing and macroalgal growth via nutrient loading. The model was run for changes in sea surface temperature and water chemistry predicted by the rise in atmospheric CO2 projected from the IPCC's fossil-fuel intensive A1FI scenario during this century. Results demonstrated that severe acidification and warming alone can lower reef resilience (via impairment of coral growth and increased coral mortality) even under high grazing intensity and low nutrients. Further, the threshold at which herbivore overfishing (reduced grazing) leads to a coral–algal phase shift was lowered by acidification and warming. These analyses support two important conclusions: Firstly, reefs already subjected to herbivore overfishing and nutrification are likely to be more vulnerable to increasing CO2. Secondly, under CO2 regimes above 450–500 ppm, management of local-scale disturbances will become critical to keeping reefs within an Acropora-rich domain.

Foraminifer Shell Weight and Fragmentation: A Quantitative Study of the Influence of Temperature, [CO32-] and Dissolution on Proxies of the Marine Carbonate System

NASA Astrophysics Data System (ADS)

Mekik, F.; Pourmand, A.; Ward, B. M.

2015-12-01

Quantifying the various components of the marine carbonate system is important for understanding anthropogenic ocean acidification, and the rates and magnitudes of ocean acidification/ alkalization events in Earth's past. We performed multiple statistical analyses (factor analysis, partial correlations, multiple regression analysis and independent samples t -tests) on core top data using the Globorotalia menardii fragmentation index (MFI) in 89 core tops from across the tropical Pacific, Atlantic and Indian Oceans, the fragmentation trend of four species of foraminifers (Globorotalia truncatulinoides, G. menardii, Neogloboquadrina dutertrei and Pulleniatina obliquiloculata) in the EEP, tropical Atlantic and tropical Indian Ocean core tops, and Globorotalia menardii shell weight in a suite of 25 core tops the EEP in order to isolate the effects of surface ocean parameters such as temperature and [CO32-] from dissolution in sediments. Surface ocean parameters showed no significant effect on the G. menardii fragmentation index. We found no statistically significant influence of habitat water temperature or [CO32-] on foraminifer fragmentation in any of four species. While we found a strong influence of habitat water [CO32-] on the size normalized shell weight proxy in N. dutertrei and Pulleniatina obliquiloculata in our previous work, we found a much reduced influence of [CO32-] on the shell weight of G. menardii, which is most influenced by shell dissolution.

Interaction effects between sender and receiver processes in indirect transmission of Campylobacter jejuni between broilers.

PubMed

van Bunnik, Bram A D; Hagenaars, Thomas J; Bolder, Nico M; Nodelijk, Gonnie; de Jong, Mart C M

2012-07-25

Infectious diseases in plants, animals and humans are often transmitted indirectly between hosts (or between groups of hosts), i.e. via some route through the environment instead of via direct contacts between these hosts. Here we study indirect transmission experimentally, using transmission of Campylobacter jejuni (C. jejuni) between spatially separated broilers as a model system. We distinguish three stages in the process of indirect transmission; (1) an infectious "sender" excretes the agent, after which (2) the agent is transported via some route to a susceptible "receiver", and subsequently (3) the receiver becomes colonised by the agent. The role of the sender and receiver side (stage 1 and stage 3) was studied here by using acidification of the drinking water as a modulation mechanism. In the experiment one control group and three treatment groups were monitored for the presence of C. jejuni by taking daily cloacal swabs. The three treatments consisted of acidification of the drinking water of the inoculated animals (the senders), acidification of the drinking water of the susceptible animals (the receivers) or acidification of the drinking water of both inoculated and susceptible animals. In the control group 12 animals got colonised out of a possible 40, in each treatment groups 3 animals out of a possible 40 were found colonised with C. jejuni. The results of the experiments show a significant decrease in transmission rate (β) between the control groups and treatment groups (p < 0.01 for all groups) but not between different treatments; there is a significant negative interaction effect when both the sender and the receiver group receive acidified drinking water (p = 0.01). This negative interaction effect could be due to selection of bacteria already at the sender side thereby diminishing the effect of acidification at the receiver side.

Shifts in coral reef biogeochemistry and resulting acidification linked to offshore productivity

NASA Astrophysics Data System (ADS)

Yeakel, Kiley L.; Andersson, Andreas J.; Bates, Nicholas R.; Noyes, Timothy J.; Collins, Andrew; Garley, Rebecca

2015-11-01

Oceanic uptake of anthropogenic carbon dioxide (CO2) has acidified open-ocean surface waters by 0.1 pH units since preindustrial times. Despite unequivocal evidence of ocean acidification (OA) via open-ocean measurements for the past several decades, it has yet to be documented in near-shore and coral reef environments. A lack of long-term measurements from these environments restricts our understanding of the natural variability and controls of seawater CO2-carbonate chemistry and biogeochemistry, which is essential to make accurate predictions on the effects of future OA on coral reefs. Here, in a 5-y study of the Bermuda coral reef, we show evidence that variations in reef biogeochemical processes drive interannual changes in seawater pH and Ωaragonite that are partly controlled by offshore processes. Rapid acidification events driven by shifts toward increasing net calcification and net heterotrophy were observed during the summers of 2010 and 2011, with the frequency and extent of such events corresponding to increased offshore productivity. These events also coincided with a negative winter North Atlantic Oscillation (NAO) index, which historically has been associated with extensive offshore mixing and greater primary productivity at the Bermuda Atlantic Time-series Study (BATS) site. Our results reveal that coral reefs undergo natural interannual events of rapid acidification due to shifts in reef biogeochemical processes that may be linked to offshore productivity and ultimately controlled by larger-scale climatic and oceanographic processes.

Shifts in coral reef biogeochemistry and resulting acidification linked to offshore productivity.

PubMed

Yeakel, Kiley L; Andersson, Andreas J; Bates, Nicholas R; Noyes, Timothy J; Collins, Andrew; Garley, Rebecca

2015-11-24

Oceanic uptake of anthropogenic carbon dioxide (CO2) has acidified open-ocean surface waters by 0.1 pH units since preindustrial times. Despite unequivocal evidence of ocean acidification (OA) via open-ocean measurements for the past several decades, it has yet to be documented in near-shore and coral reef environments. A lack of long-term measurements from these environments restricts our understanding of the natural variability and controls of seawater CO2-carbonate chemistry and biogeochemistry, which is essential to make accurate predictions on the effects of future OA on coral reefs. Here, in a 5-y study of the Bermuda coral reef, we show evidence that variations in reef biogeochemical processes drive interannual changes in seawater pH and Ωaragonite that are partly controlled by offshore processes. Rapid acidification events driven by shifts toward increasing net calcification and net heterotrophy were observed during the summers of 2010 and 2011, with the frequency and extent of such events corresponding to increased offshore productivity. These events also coincided with a negative winter North Atlantic Oscillation (NAO) index, which historically has been associated with extensive offshore mixing and greater primary productivity at the Bermuda Atlantic Time-series Study (BATS) site. Our results reveal that coral reefs undergo natural interannual events of rapid acidification due to shifts in reef biogeochemical processes that may be linked to offshore productivity and ultimately controlled by larger-scale climatic and oceanographic processes.

Shifts in coral reef biogeochemistry and resulting acidification linked to offshore productivity

PubMed Central

Yeakel, Kiley L.; Andersson, Andreas J.; Bates, Nicholas R.; Noyes, Timothy J.; Collins, Andrew; Garley, Rebecca

2015-01-01

Oceanic uptake of anthropogenic carbon dioxide (CO2) has acidified open-ocean surface waters by 0.1 pH units since preindustrial times. Despite unequivocal evidence of ocean acidification (OA) via open-ocean measurements for the past several decades, it has yet to be documented in near-shore and coral reef environments. A lack of long-term measurements from these environments restricts our understanding of the natural variability and controls of seawater CO2-carbonate chemistry and biogeochemistry, which is essential to make accurate predictions on the effects of future OA on coral reefs. Here, in a 5-y study of the Bermuda coral reef, we show evidence that variations in reef biogeochemical processes drive interannual changes in seawater pH and Ωaragonite that are partly controlled by offshore processes. Rapid acidification events driven by shifts toward increasing net calcification and net heterotrophy were observed during the summers of 2010 and 2011, with the frequency and extent of such events corresponding to increased offshore productivity. These events also coincided with a negative winter North Atlantic Oscillation (NAO) index, which historically has been associated with extensive offshore mixing and greater primary productivity at the Bermuda Atlantic Time-series Study (BATS) site. Our results reveal that coral reefs undergo natural interannual events of rapid acidification due to shifts in reef biogeochemical processes that may be linked to offshore productivity and ultimately controlled by larger-scale climatic and oceanographic processes. PMID:26553977

Resistance of biofilm-covered mortars to microbiologically influenced deterioration simulated by sulfuric acid exposure

DOE Office of Scientific and Technical Information (OSTI.GOV)

Soleimani, Sahar, E-mail: ssoleima@connect.carleton.ca; Isgor, O. Burkan, E-mail: burkan_isgor@carleton.ca; Ormeci, Banu, E-mail: banu_ormeci@carleton.ca

2013-11-15

Following the reported success of biofilm applications on metal surfaces to inhibit microbiologically influenced corrosion, effectiveness and sustainability of E. coli DH5α biofilm on mortar surface to prevent microbiologically influenced concrete deterioration (MICD) are investigated. Experiments simulating microbial attack were carried out by exposing incrementally biofilm-covered mortar specimens to sulfuric acid solutions with pH ranging from 3 to 6. Results showed that calcium concentration in control reactors without biofilm was 23–47% higher than the reactors with biofilm-covered mortar. Formation of amorphous silica gel as an indication of early stages of acid attack was observed only on the control mortar specimensmore » without biofilm. During acidification, the biofilm continued to grow and its thickness almost doubled from ∼ 30 μm before acidification to ∼ 60 μm after acidification. These results demonstrated that E. coli DH5α biofilm was able to provide a protective and sustainable barrier on mortar surfaces against medium to strong sulfuric acid attack. -- Highlights: •Effectiveness of E.coli DH5α biofilm to prevent MICD was studied. •Conditions that lead to MICD were simulated by chemical acidification. •Biofilm-covered mortar specimens were exposed to sulfuric acid solutions. •The presence of biofilm helped reduce the chemically-induced mortar deterioration. •Biofilm remained alive and continued to grow during the acidification process.« less

Long-term studies (1871-2000) on acidification and recovery of lakes in the Bohemian Forest (central Europe).

PubMed

Vrba, Jaroslav; Kopácek, Jirí; Fott, Jan; Kohout, Leos; Nedbalová, Linda; Prazáková, Miroslava; Soldán, Tomás; Schaumburg, Jochen

2003-07-01

This paper evaluates long-term changes in the atmospheric depositions of S and N compounds, lake water quality, and biodiversity at eight glacial lakes in the Bohemian Forest over the past 130 years. This time interval covers (i) the 'background' pre-acidification status of the lakes, (ii) a period of changes in the communities that can be partly explained by introduction of fish, (iii) a period of strong lake acidification with its adverse impacts on the communities, (iv) the lake reversal from acidity, which includes the recent status of the lakes. The lake water chemistry has followed-with a characteristic hysteresis-both the sharp increase and decline in the deposition trends of strong anions. Remarkable changes in biota have mirrored the changing water quality. Fish became extinct and most species of zooplankton (Crustacea) and benthos (Ephemeroptera and Plecoptera) retreated due to the lake water acidification. Independent of ongoing chemical reversal, microorganisms remain dominant in the recent plankton biomass as well as in controlling the pelagic food webs. The first signs of the forthcoming biological recovery have already been evidenced in some lakes, such as the population of Ceriodaphnia quadrangula (Cladocera) returning into the pelagial of one lake or the increase in both phytoplankton biomass and rotifer numbers in another lake.

Seasonal controls of aragonite saturation states in the Gulf of Maine

NASA Astrophysics Data System (ADS)

Wang, Zhaohui Aleck; Lawson, Gareth L.; Pilskaln, Cynthia H.; Maas, Amy E.

2017-01-01

The Gulf of Maine (GoME) is a shelf region especially vulnerable to ocean acidification (OA) due to natural conditions of low pH and aragonite saturation states (Ω-Ar). This study is the first to assess the major oceanic processes controlling seasonal variability of the carbonate system and its linkages with pteropod abundance in Wilkinson Basin in the GoME. Two years of seasonal sampling cruises suggest that water-column carbonate chemistry in the region undergoes a seasonal cycle, wherein the annual cycle of stratification-overturn, primary production, respiration-remineralization and mixing all play important roles, at distinct spatiotemporal scales. Surface production was tightly coupled with remineralization in the benthic nepheloid layer during high production seasons, which results in occasional aragonite undersaturation. From spring to summer, carbonate chemistry in the surface across Wilkinson Basin reflects a transition from a production-respiration balanced system to a net autotropic system. Mean water-column Ω-Ar and abundance of large thecosomatous pteropods show some correlation, although patchiness and discrete cohort reproductive success likely also influence their abundance. Overall, photosynthesis-respiration is the primary driving force controlling Ω-Ar variability during the spring-to-summer transition as well as over the seasonal cycle. However, calcium carbonate (CaCO3) dissolution appears to occur near bottom in fall and winter when bottom water Ω-Ar is generally low but slightly above 1. This is accompanied by a decrease in pteropod abundance that is consistent with previous CaCO3 flux trap measurements. The region might experience persistent subsurface aragonite undersaturation in 30-40 years under continued ocean acidification.

EPA Issues November 15, 2010 Memorandum: Integrated Reporting and Listing Decisions Related to Ocean Acidification

EPA Pesticide Factsheets

The memorandum provides information to assist regions and states in preparing and reviewing Integrated Reports related to ocean acidification (OA) impacts under Sections 303(d), 305(b) and 314 of the Clean Water Act (CWA).

Effect of Interannual Variability on the Ocean Acidification-induced Habitat Restriction of the Humboldt Current System.

NASA Astrophysics Data System (ADS)

Franco, A. C.; Gruber, N.; Munnich, M.

2016-02-01

The Humboldt Current System (HCS) is one of the most productive ecosystems in the world. This high productivity is supported by a large input of nutrients from the subsurface layers to the surface due to year-round upwelling. However, upwelling also supplies waters with low pH and low aragonite saturation state potentially affecting many organisms, especially those that calcify. The influence, extent and source of upwelled water varies substantially on interannual timescales in association with the El Niño/Southern Oscillation (ENSO) phenomenon, accentuating productivity during La Niña events and dampening it during El Niño, altering the dynamics of the whole ecosystem. On top of this natural variability, the continuing acidification of the upper ocean in response to raising atmospheric CO2 may decrease pH further and increase the volume of water corrosive to aragonite in this region, leading to a progressively smaller suitable habitat for sensitive organisms. Here we use an eddy-resolving basin-scale ocean model that covers the whole Pacific Ocean with higher resolution near the coast off South America ( 6 km) to investigate the role of ENSO events on low aragonite saturation episodes and productivity variations. We compare 2 simulations: a hindcast simulation that spans the last 30 years and a future scenario that represents year 2090 (following IPCC's "business-as-usual" scenario). We found that in the region off Peru, the sole effect of increasing atmospheric CO2 to 840 matm shoals the annual average aragonite saturation depth to 30 m, creating a year round presence of aragonite undersaturated water in the euphotic zone. We then contrast the effect on primary productivity and the aragonite saturation state of at least eight El Niño and eight La Niña episodes that have been reported for the past 30 years, in an attempt to answer the question: does habitat availability under future ocean acidification will resemble a pervasive La Niña-like state?

Changes in lead and zinc lability during weathering-induced acidification of desert mine tailings: Coupling chemical and micro-scale analyses.

PubMed

Hayes, Sarah M; White, Scott A; Thompson, Thomas L; Maier, Raina M; Chorover, Jon

2009-12-01

Desert mine tailings may accumulate toxic metals in the near surface centimeters because of low water through-flux rates. Along with other constraints, metal toxicity precludes natural plant colonization even over decadal time scales. Since unconsolidated particles can be subjected to transport by wind and water erosion, potentially resulting in direct human and ecosystem exposure, there is a need to know how the lability and form of metals change in the tailings weathering environment. A combination of chemical extractions, X-ray diffraction, micro-X-ray fluorescence spectroscopy, and micro-Raman spectroscopy were employed to study Pb and Zn contamination in surficial arid mine tailings from the Arizona Klondyke State Superfund Site. Initial site characterization indicated a wide range in pH (2.5 to 8.0) in the surficial tailings pile. Ligand-promoted (DTPA) extractions, used to assess plant-available metal pools, showed decreasing available Zn and Mn with progressive tailings acidification. Aluminum shows the inverse trend, and Pb and Fe show more complex pH dependence. Since the tailings derive from a common source and parent mineralogy, it is presumed that variations in pH and "bioavailable" metal concentrations result from associated variation in particle-scale geochemistry. Four sub-samples, ranging in pH from 2.6 to 5.4, were subjected to further characterization to elucidate micro-scale controls on metal mobility. With acidification, total Pb (ranging from 5 - 13 g kg(-1)) was increasingly associated with Fe and S in plumbojarosite aggregates. For Zn, both total (0.4 - 6 g kg(-1)) and labile fractions decreased with decreasing pH. Zinc was found to be primarily associated with the secondary Mn phases manjiroite and chalcophanite. The results suggest that progressive tailings acidification diminishes the overall lability of the total Pb and Zn pools.

Natural variability of pCO2 and pH in the Atlantic and Pacific coastal margins of the U.S

NASA Astrophysics Data System (ADS)

Sutton, A. J.; Sabine, C. L.; Feely, R. A.; Newton, J.; Salisbury, J.; Vandemark, D. C.; Musielewicz, S. B.; Maenner-Jones, S.; Bott, R.; Lawrence-Slavas, N.

2011-12-01

The discovery that seawater chemistry is changing as a result of carbon dioxide (CO2) emissions, referred to as "ocean acidification", has prompted a large effort to understand how this changing chemistry will impact marine life. Changes in carbon chemistry have been documented in the open ocean; however, in dynamic coastal systems where many marine species live, ocean acidification and the natural biogeochemical variability that organisms are currently exposed to are poorly quantified. In 2010 we began equipping coastal moorings currently measuring pCO2 with pH and other biogeochemical sensors to measure ocean acidification parameters at 3 hour intervals in the surface water. Here we present the magnitude and diurnal to seasonal variability of pCO2 and pH during the first year of observations at 2 sites in the Atlantic and Pacific coastal margins of the U.S.: the Gulf of Maine and outer coast of Washington state. Both the magnitude and range of pCO2 and pH values were much greater at the coastal moorings compared to the open ocean mooring at Ocean Station Papa in the North Pacific and also varied between the two coastal mooring sites. We observed maximum pCO2 values in coastal waters exceeding predicted values for the open ocean at 2x pre-industrial CO2 levels. The range of pCO2 and pH values during this time series was approximately 4 times the range observed at open ocean mooring Papa (2007-2011 time series). In many cases, large variance was observed at short time scales, with values fluctuating more than 200 μatm pCO2 and 0.2 pH between 3-hour cycles. These types of observations are critical for understanding how ocean acidification will manifest in naturally dynamic coastal systems and for informing the experimental design of species response studies that aim to mimic carbon chemistry experienced by coastal marine organisms.

Increasing arsenic concentrations in runoff from 12 small forested catchments (Czech Republic, Central Europe): patterns and controls.

PubMed

Novak, Martin; Erbanova, Lucie; Fottova, Daniela; Voldrichova, Petra; Prechova, Eva; Blaha, Vladimir; Veselovsky, Frantisek; Krachler, Michael

2010-08-01

The 40-year long period of heavy industrialization in Central Europe (1950-1990) was accompanied by burning of arsenic-rich lignite in thermal power plants, and accumulation of anthropogenic arsenic in forest soils. There are fears that retreating acidification may lead to arsenic mobilization into drinking water, caused by competitive ligand exchange. We present monthly arsenic concentrations in surface runoff from 12 headwater catchments in the Czech Republic for a period of 13 years (1996-2008). The studied area was characterized by a north-south gradient of decreasing pollution. Acidification, caused mainly by SOx and NOx emissions from power plants, has been retreating since 1987. Between 1996 and 2003, maximum arsenic concentrations in runoff did not change, and were < 1 ppb in the rural south and < 2 ppb in the industrial north. During the subsequent two years, 2004-2005, maximum arsenic concentrations in runoff increased, reaching 60% of the drinking water limit (10 ppb). Starting in 2006, maximum arsenic concentrations returned to lower values at most sites. We discuss three possible causes of the recent arsenic concentration maximum in runoff. We rule out retreating acidification and a pulse of high industrial emission rates as possible controls. The pH of runoff has not changed since 1996, and is still too low (<6.5) at most sites for an As-OH(-) ligand exchange to become significant. Elevated arsenic concentrations in runoff in 2004-2005 may reflect climate change through changing hydrological conditions at some, but not all sites. Dry conditions may result in elevated production of DOC and sulfur oxidation in the soil. Subsequent wet conditions may be accompanied by acidification leading to faster dissolution of arsenic-bearing sulfides, dissolution of arsenic-bearing Fe-oxyhydroxides, and elevated transport of arsenic sorbed on organic matter. Anaerobic domains exist in normally well-aerated upland soils for hours-to-days following precipitation events. 2010 Elsevier B.V. All rights reserved.

Changes in lead and zinc lability during weathering-induced acidification of desert mine tailings: Coupling chemical and micro-scale analyses

PubMed Central

Hayes, Sarah M.; White, Scott A.; Thompson, Thomas L.; Maier, Raina M.; Chorover, Jon

2009-01-01

Desert mine tailings may accumulate toxic metals in the near surface centimeters because of low water through-flux rates. Along with other constraints, metal toxicity precludes natural plant colonization even over decadal time scales. Since unconsolidated particles can be subjected to transport by wind and water erosion, potentially resulting in direct human and ecosystem exposure, there is a need to know how the lability and form of metals change in the tailings weathering environment. A combination of chemical extractions, X-ray diffraction, micro-X-ray fluorescence spectroscopy, and micro-Raman spectroscopy were employed to study Pb and Zn contamination in surficial arid mine tailings from the Arizona Klondyke State Superfund Site. Initial site characterization indicated a wide range in pH (2.5 to 8.0) in the surficial tailings pile. Ligand-promoted (DTPA) extractions, used to assess plant-available metal pools, showed decreasing available Zn and Mn with progressive tailings acidification. Aluminum shows the inverse trend, and Pb and Fe show more complex pH dependence. Since the tailings derive from a common source and parent mineralogy, it is presumed that variations in pH and “bioavailable” metal concentrations result from associated variation in particle-scale geochemistry. Four sub-samples, ranging in pH from 2.6 to 5.4, were subjected to further characterization to elucidate micro-scale controls on metal mobility. With acidification, total Pb (ranging from 5 – 13 g kg−1) was increasingly associated with Fe and S in plumbojarosite aggregates. For Zn, both total (0.4 – 6 g kg−1) and labile fractions decreased with decreasing pH. Zinc was found to be primarily associated with the secondary Mn phases manjiroite and chalcophanite. The results suggest that progressive tailings acidification diminishes the overall lability of the total Pb and Zn pools. PMID:20161492

Short-Term Summer Inundation as a Measure to Counteract Acidification in Rich Fens

PubMed Central

Mettrop, Ivan S.; Cusell, Casper; Kooijman, Annemieke M.; Lamers, Leon P. M.

2015-01-01

In regions with intensive agriculture, water level fluctuation in wetlands has generally become constricted within narrow limits. Water authorities are, however, considering the re-establishment of fluctuating water levels as a management tool in biodiverse, base-rich fens (‘rich fens’). This includes temporary inundation with surface water from ditches, which may play an important role in counteracting acidification in order to conserve and restore biodiversity. Inundation may result in an increased acid neutralizing capacity (ANC) for two reasons: infiltration of base-rich inundation water into peat soils, and microbial alkalinity generation under anaerobic conditions. The main objectives of this study were to test whether short-term (2 weeks) summer inundation is more effective than short-term winter inundation to restore the ANC in the upper 10 cm of non-floating peat soils, and to explain potential differences. Large-scale field experiments were conducted for five years in base-rich fens and Sphagnum-dominated poor fens. Winter inundation did not result in increased porewater ANC, because infiltration was inhibited in the waterlogged peat and evapotranspiration rates were relatively low. Also, low temperatures limit microbial alkalinity generation. In summer, however, when temperature and evapotranspiration rates are higher, inundation resulted in increased porewater Ca and HCO3 - concentrations, but only in areas with characteristic rich fen bryophytes. This increase was not only due to stronger infiltration into the soil, but also to higher microbial alkalinity generation under anaerobic conditions. In contrast, porewater ANC did not increase in Sphagnum-plots as a result of the ability of Sphagnum spp. to acidify their environment. In both rich and poor fens, flooding-induced P-mobilization remained sufficiently low to safeguard P-limited vegetation. NO3 - and NH4 + dynamics showed no considerable changes either. In conclusion, short-term summer inundation with base-rich and nutrient-poor surface water is considered beneficial in the management of non-floating rich fens, and much more effective than winter inundation. PMID:26637121

Response of predatory zooplankton populations to the experimental acidification of Little Rock Lake, Wisconsin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sierszen, M.E.; Frost, T.M.

1993-01-01

To assess the effects of lake acidification on large predatory zooplankton, the authors monitored population levels of four limnetic taxa for 6 years in a lake with two basins, one of which was experimentally acidified (2 years at each of three levels: pH 5.6, 5.2 and 4.7). Concentrations of phantom midge (Chaoborus spp.), the most abundant large predator, remained similar in the treatment and reference basins until the fourth year (pH 5.2) when they increased in the treatment basin. In contrast, Epischura lacustris and Leptodora kindtii disappeared from limnetic samples, and water mites declined to near zero upon acidification. Treatmentmore » basin populations of E. lacustris declined sharply during the second year of acidification. The nature of the decline suggested sensitivity of an early life stage during the first year at pH 5.6. Leptodora kindtii showed no population response at pH 5.6, but declined to essentially zero at pH 5.2. Treatment basin populations of water mites fluctuated until declining in the fifth and sixth years (pH 4.7). These changes indicate a variety of direct and indirect responses to lake acidification.« less

Stable Carbon Isotope Characterization of CO2 Loss in Acid Mine Drainage Impacted Stream Water: Observations from a Laboratory Experiment

NASA Astrophysics Data System (ADS)

Ali, H. N.; Atekwana, E. A.

2007-05-01

Water from an acid mine drainage spring, ground water from a mine tailings pile, stream water and tap water were acidified to simulate acid mine drainage (AMD) contamination. The objective was to determine how acidification of stream water by AMD affected DIC loss and carbon isotope fraction. Two 20 L HDP containers (reactors) containing samples from each source were left un-acidified and allowed to evolve under ambient conditions for several weeks in the laboratory and two others were acidified. Acidification was carried out progressively with sulfuric acid to pH <3. For acidified samples, one reactor was acidified open to the atmosphere and the other closed from contact with atmosphere and CO2(g) was collected under vacuum. The un-acidified samples did not show significant alkalinity and DIC loss, and the 13C of DIC was enriched with time. The acidified samples showed decrease in alkalinity and DIC and increase in the 13C of DIC and CO2(g) with progressive acidification. The enrichment of 13C of DIC for un-acidified samples was due to exchange with atmospheric CO2. On the other hand, the 13C enrichment in the acidified samples was due to fractionation during dehydration of HCO3- and diffusive loss of CO2(g) from the aqueous phase. The actual values measured depended on the amount of CO2 lost from the aqueous phase during acidification. Samples with greater CO2 loss (closed acidification) had greater 13C enrichment. Beyond the HCO3- titration end point, the δ13C of DIC and CO2(g) was similar and nearly constant. The result of this study suggests that AMD effects on DIC can be modeled as a first order kinetic reaction and the isotope enrichment modeled using Rayleigh distillation.

Ocean Warming, More than Acidification, Reduces Shell Strength in a Commercial Shellfish Species during Food Limitation

PubMed Central

Mackenzie, Clara L.; Ormondroyd, Graham A.; Curling, Simon F.; Ball, Richard J.; Whiteley, Nia M.; Malham, Shelagh K.

2014-01-01

Ocean surface pH levels are predicted to fall by 0.3–0.4 pH units by the end of the century and are likely to coincide with an increase in sea surface temperature of 2–4°C. The combined effect of ocean acidification and warming on the functional properties of bivalve shells is largely unknown and of growing concern as the shell provides protection from mechanical and environmental challenges. We examined the effects of near-future pH (ambient pH –0.4 pH units) and warming (ambient temperature +4°C) on the shells of the commercially important bivalve, Mytilus edulis when fed for a limited period (4–6 h day−1). After six months exposure, warming, but not acidification, significantly reduced shell strength determined as reductions in the maximum load endured by the shells. However, acidification resulted in a reduction in shell flex before failure. Reductions in shell strength with warming could not be explained by alterations in morphology, or shell composition but were accompanied by reductions in shell surface area, and by a fall in whole-body condition index. It appears that warming has an indirect effect on shell strength by re-allocating energy from shell formation to support temperature-related increases in maintenance costs, especially as food supply was limited and the mussels were probably relying on internal energy reserves. The maintenance of shell strength despite seawater acidification suggests that biomineralisation processes are unaffected by the associated changes in CaCO3 saturation levels. We conclude that under near-future climate change conditions, ocean warming will pose a greater risk to shell integrity in M. edulis than ocean acidification when food availability is limited. PMID:24489785

Ocean warming, more than acidification, reduces shell strength in a commercial shellfish species during food limitation.

PubMed

Mackenzie, Clara L; Ormondroyd, Graham A; Curling, Simon F; Ball, Richard J; Whiteley, Nia M; Malham, Shelagh K

2014-01-01

Ocean surface pH levels are predicted to fall by 0.3-0.4 pH units by the end of the century and are likely to coincide with an increase in sea surface temperature of 2-4 °C. The combined effect of ocean acidification and warming on the functional properties of bivalve shells is largely unknown and of growing concern as the shell provides protection from mechanical and environmental challenges. We examined the effects of near-future pH (ambient pH -0.4 pH units) and warming (ambient temperature +4 °C) on the shells of the commercially important bivalve, Mytilus edulis when fed for a limited period (4-6 h day(-1)). After six months exposure, warming, but not acidification, significantly reduced shell strength determined as reductions in the maximum load endured by the shells. However, acidification resulted in a reduction in shell flex before failure. Reductions in shell strength with warming could not be explained by alterations in morphology, or shell composition but were accompanied by reductions in shell surface area, and by a fall in whole-body condition index. It appears that warming has an indirect effect on shell strength by re-allocating energy from shell formation to support temperature-related increases in maintenance costs, especially as food supply was limited and the mussels were probably relying on internal energy reserves. The maintenance of shell strength despite seawater acidification suggests that biomineralisation processes are unaffected by the associated changes in CaCO3 saturation levels. We conclude that under near-future climate change conditions, ocean warming will pose a greater risk to shell integrity in M. edulis than ocean acidification when food availability is limited.

Thermally stratified acid water in late winter - a key factor inducing self-accelerating processes which increase acidification

Treesearch

Hans Hultberg

1976-01-01

Ion separation of acid air pollutants out of snow causes-sudden, deep pH-drops in lakes and running waters at an early stage of snowmelting. These pH-drops have drastic effects on fish populations and are suggested to be the main cause of Sphagnum invasion and changes in the microflora already at an early stage of acidification, i.e. when summer pH-...

Recovery from chronic and snowmelt acidification: Long-term trends in stream and soil water chemistry at the Hubbard Brook Experimental Forest, New Hampshire, USA

NASA Astrophysics Data System (ADS)

Fuss, Colin B.; Driscoll, Charles T.; Campbell, John L.

2015-11-01

Atmospheric acid deposition of sulfate and nitrate has declined markedly in the northeastern United States due to emissions controls. We investigated long-term trends in soil water (1984-2011) and stream water (1982-2011) chemistry along an elevation gradient of a forested watershed to evaluate the progress of recovery of drainage waters from acidic deposition at the Hubbard Brook Experimental Forest in the White Mountains of New Hampshire, USA. We found slowed losses of base cations from soil and decreased mobilization of dissolved inorganic aluminum. Stream water pH at the watershed outlet increased at a rate of 0.01 units yr-1, and the acid neutralizing capacity (ANC) gained 0.88 µeq L-1 yr-1. Dissolved organic carbon generally decreased in stream water and soil solutions, contrary to trends observed at many North American and European sites. We compared whole-year hydrochemical trends with those during snowmelt, which is the highest-flow and lowest ANC period of the year, indicative of episodic acidification. Stream water during snowmelt had long-term trends of increasing ANC and pH at a rate very similar to the whole-year record, with closely related steady decreases in sulfate. A more rapid decline in stream water nitrate during snowmelt compared with the whole-year trend may be due, in part, to the marked decrease in atmospheric nitrate deposition during the last decade. The similarity between the whole-year trends and those of the snowmelt period is an important finding that demonstrates a consistency between recovery from chronic acidification during base flow and abatement of snowmelt acidification.

Elevated carbon dioxide alters the plasma composition and behaviour of a shark.

PubMed

Green, Leon; Jutfelt, Fredrik

2014-09-01

Increased carbon emissions from fossil fuels are increasing the pCO2 of the ocean surface waters in a process called ocean acidification. Elevated water pCO2 can induce physiological and behavioural effects in teleost fishes, although there appear to be large differences in sensitivity between species. There is currently no information available on the possible responses to future ocean acidification in elasmobranch fishes. We exposed small-spotted catsharks (Scyliorhinus canicula) to either control conditions or a year 2100 scenario of 990 μatm pCO2 for four weeks. We did not detect treatment effects on growth, resting metabolic rate, aerobic scope, skin denticle ultrastructure or skin denticle morphology. However, we found that the elevated pCO2 group buffered internal acidosis via [Formula: see text] accumulation with an associated increase in Na(+), indicating that the blood chemistry remained altered despite the long acclimation period. The elevated pCO2 group also exhibited a shift in their nocturnal swimming pattern from a pattern of many starts and stops to more continuous swimming. Although CO2-exposed teleost fishes can display reduced behavioural asymmetry (lateralization), the CO2-exposed sharks showed increased lateralization. These behavioural effects may suggest that elasmobranch neurophysiology is affected by CO2, as in some teleosts, or that the sharks detect CO2 as a constant stressor, which leads to altered behaviour. The potential direct effects of ocean acidification should henceforth be considered when assessing future anthropogenic effects on sharks. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

USGS Arctic Ocean carbon cruise 2010: field activity H-03-10-AR to collect carbon data in the Arctic Ocean, August - September 2010

USGS Publications Warehouse

Robbins, Lisa L.; Yates, Kimberly K.; Gove, Matthew D.; Knorr, Paul O.; Wynn, Jonathan; Byrne, Robert H.; Liu, Xuewu

2013-01-01

Carbon dioxide (CO2) in the atmosphere is absorbed at the surface of the ocean by reacting with seawater to form carbonic acid, a weak, naturally occurring acid. As atmospheric carbon dioxide increases, the concentration of carbonic acid in seawater also increases, causing a decrease in ocean pH and carbonate mineral saturation states, a process known as ocean acidification. The oceans have absorbed approximately 525 billion tons of carbon dioxide from the atmosphere, or about one-quarter to one-third of the anthropogenic carbon emissions released since the beginning of the Industrial Revolution (Sabine and others, 2004). Global surveys of ocean chemistry have revealed that seawater pH has decreased by about 0.1 units (from a pH of 8.2 to 8.1) since the 1700s due to absorption of carbon dioxide (Caldeira and Wickett, 2003; Orr and others, 2005; Raven and others, 2005). Modeling studies, based on Intergovernmental Panel on Climate Change (IPCC) CO2 emission scenarios, predict that atmospheric carbon dioxide levels could reach more than 500 parts per million (ppm) by the middle of this century and 800 ppm by the year 2100, causing an additional decrease in surface water pH of 0.3 pH units. Ocean acidification is a global threat and is already having profound and deleterious effects on the geology, biology, chemistry, and socioeconomic resources of coastal and marine habitats (Raven and others, 2005; Ruttiman, 2006). The polar and sub-polar seas have been identified as the bellwethers for global ocean acidification.

USGS Arctic Ocean carbon cruise 2011: field activity H-01-11-AR to collect carbon data in the Arctic Ocean, August - September 2011

USGS Publications Warehouse

Robbins, Lisa L.; Yates, Kimberly K.; Knorr, Paul O.; Wynn, Jonathan; Lisle, John; Buczkowski, Brian J.; Moore, Barbara; Mayer, Larry; Armstrong, Andrew; Byrne, Robert H.; Liu, Xuewu

2013-01-01

Carbon dioxide (CO2) in the atmosphere is absorbed at the surface of the ocean by reacting with seawater to form a weak, naturally occurring acid called carbonic acid. As atmospheric carbon dioxide increases, the concentration of carbonic acid in seawater also increases, causing a decrease in ocean pH and carbonate mineral saturation states, a process known as ocean acidification. The oceans have absorbed approximately 525 billion tons of carbon dioxide from the atmosphere, or about one-quarter to one-third of the anthropogenic carbon emissions released since the beginning of the Industrial Revolution (Sabine and others, 2004). Global surveys of ocean chemistry have revealed that seawater pH has decreased by about 0.1 units (from a pH of 8.2 to 8.1) since the 1700s due to absorption of carbon dioxide (Caldeira and Wickett, 2003; Orr and others, 2005; Raven and others, 2005). Modeling studies, based on Intergovernmental Panel on Climate Change (IPCC) CO2 emission scenarios, predict that atmospheric carbon dioxide levels could reach more than 500 parts per million (ppm) by the middle of this century and 800 ppm by the year 2100, causing an additional decrease in surface water pH of 0.3 pH units. Ocean acidification is a global threat and is already having profound and deleterious effects on the geology, biology, chemistry, and socioeconomic resources of coastal and marine habitats (Raven and others, 2005; Ruttiman, 2006). The polar and sub-polar seas have been identified as the bellwethers for global ocean acidification.

Treatment impacts on temporal microbial community dynamics during phytostabilization of acid-generating mine tailings in semiarid regions.

PubMed

Valentín-Vargas, Alexis; Neilson, Julia W; Root, Robert A; Chorover, Jon; Maier, Raina M

2018-03-15

Direct revegetation, or phytostabilization, is a containment strategy for contaminant metals associated with mine tailings in semiarid regions. The weathering of sulfide ore-derived tailings frequently drives acidification that inhibits plant establishment resulting in materials prone to wind and water dispersal. The specific objective of this study was to associate pyritic mine waste acidification, characterized through pore-water chemistry analysis, with dynamic changes in microbial community diversity and phylogenetic composition, and to evaluate the influence of different treatment strategies on the control of acidification dynamics. Samples were collected from a highly instrumented one-year mesocosm study that included the following treatments: 1) unamended tailings control; 2) tailings amended with 15% compost; and 3) the 15% compost-amended tailings planted with Atriplex lentiformis. Tailings samples were collected at 0, 3, 6 and 12months and pore water chemistry was monitored as an indicator of acidification and weathering processes. Results confirmed that the acidification process for pyritic mine tailings is associated with a temporal progression of bacterial and archaeal phylotypes from pH sensitive Thiobacillus and Thiomonas to communities dominated by Leptospirillum and Ferroplasma. Pore-water chemistry indicated that weathering rates were highest when Leptospirillum was most abundant. The planted treatment was most successful in disrupting the successional evolution of the Fe/S-oxidizing community. Plant establishment stimulated growth of plant-growth-promoting heterotrophic phylotypes and controlled the proliferation of lithoautotrophic Fe/S-oxidizers. The results suggest the potential for eco-engineering a microbial inoculum to stimulate plant establishment and inhibit proliferation of the most efficient Fe/S-oxidizing phylotypes. Copyright © 2017 Elsevier B.V. All rights reserved.

Predicting the Response of Molluscs to the Impact of Ocean Acidification

PubMed Central

Parker, Laura M.; Ross, Pauline M.; O’Connor, Wayne A.; Pörtner, Hans O.; Scanes, Elliot; Wright, John M.

2013-01-01

Elevations in atmospheric carbon dioxide (CO2) are anticipated to acidify oceans because of fundamental changes in ocean chemistry created by CO2 absorption from the atmosphere. Over the next century, these elevated concentrations of atmospheric CO2 are expected to result in a reduction of the surface ocean waters from 8.1 to 7.7 units as well as a reduction in carbonate ion (CO32−) concentration. The potential impact that this change in ocean chemistry will have on marine and estuarine organisms and ecosystems is a growing concern for scientists worldwide. While species-specific responses to ocean acidification are widespread across a number of marine taxa, molluscs are one animal phylum with many species which are particularly vulnerable across a number of life-history stages. Molluscs make up the second largest animal phylum on earth with 30,000 species and are a major producer of CaCO3. Molluscs also provide essential ecosystem services including habitat structure and food for benthic organisms (i.e., mussel and oyster beds), purification of water through filtration and are economically valuable. Even sub lethal impacts on molluscs due to climate changed oceans will have serious consequences for global protein sources and marine ecosystems. PMID:24832802

How can present and future satellite missions support scientific studies that address ocean acidification?

USGS Publications Warehouse

Salisbury, Joseph; Vandemark, Douglas; Jonsson, Bror; Balch, William; Chakraborty, Sumit; Lohrenz, Steven; Chapron, Bertrand; Hales, Burke; Mannino, Antonio; Mathis, Jeremy T.; Reul, Nicolas; Signorini, Sergio; Wanninkhof, Rik; Yates, Kimberly K.

2016-01-01

Space-based observations offer unique capabilities for studying spatial and temporal dynamics of the upper ocean inorganic carbon cycle and, in turn, supporting research tied to ocean acidification (OA). Satellite sensors measuring sea surface temperature, color, salinity, wind, waves, currents, and sea level enable a fuller understanding of a range of physical, chemical, and biological phenomena that drive regional OA dynamics as well as the potentially varied impacts of carbon cycle change on a broad range of ecosystems. Here, we update and expand on previous work that addresses the benefits of space-based assets for OA and carbonate system studies. Carbonate chemistry and the key processes controlling surface ocean OA variability are reviewed. Synthesis of present satellite data streams and their utility in this arena are discussed, as are opportunities on the horizon for using new satellite sensors with increased spectral, temporal, and/or spatial resolution. We outline applications that include the ability to track the biochemically dynamic nature of water masses, to map coral reefs at higher resolution, to discern functional phytoplankton groups and their relationships to acid perturbations, and to track processes that contribute to acid variation near the land-ocean interface.

The impact of low pH, low aragonite saturation state on calcifying corals: an in-situ study of ocean acidification from the "ojos" of Puerto Morelos, Mexico

NASA Astrophysics Data System (ADS)

Crook, E. D.; Paytan, A.; Potts, D. C.; Hernandez Terrones, L.; Rebolledo-Vieyra, M.

2010-12-01

Recent increases in atmospheric carbon dioxide have resulted in rising aqueous CO2 concentrations that lower the pH of the oceans (Caldeira and Wickett 2003, 2005, Doney et al., 2009). It is estimated that over the next 100 years, the pH of the surface oceans will decrease by ~0.4 pH units (Orr et al., 2005), which is expected to hinder the calcifying capabilities of numerous marine organisms. Previous field work (Hall-Spencer et al., 2008) indicates that ocean acidification will negatively impact calcifying species; however, to date, very little is known about the long-term impacts of ocean acidification from the in-situ study of coral reef ecosystems. The Yucatán Peninsula of Quintana Roo, Mexico, represents an ecosystem where naturally low pH groundwater (7.14-8.07) has been discharging offshore at highly localized points (called ojos) for millennia. We present preliminary chemical and biological data on a selection of ojos from lagoon sites in Puerto Morelos, Mexico. Our findings indicate a decrease in species richness and size with proximity to the low pH waters. We address the potential long-term implications of low pH, low aragonite saturation state on coral reef ecosystems.

Atmospheric S and N deposition relates to increasing riverine transport of S and N in southwest China: Implications for soil acidification.

PubMed

Duan, Lei; Chen, Xiao; Ma, Xiaoxiao; Zhao, Bin; Larssen, Thorjørn; Wang, Shuxiao; Ye, Zhixiang

2016-11-01

Following Europe and North America, East Asia has become a global hotspot for acid deposition, with very high deposition of both sulfur (S) and nitrogen (N) occurring in large areas of southwest and southeast China. This study shows that the outflow flux of sulfate (SO 4 2- ) in three major tributaries of the Upper Yangtze River in the Sichuan Basin in southwest China has been increasing over the last three decades, which implies the regional soil acidification caused by increasing sulfur dioxide (SO 2 ) emissions. Since 2005, the outflow of SO 4 2- to the Upper Yangtze River from the Sichuan Basin has even reached the atmospheric SO 2 emission from the basin. In contrast to S emissions, the rapid increase in nitrogen (N) emissions, including nitrogen oxides (NOx) and ammonia (NH 3 ), have resulted in only a slight increase in nitrate (NO 3 - ) concentrations in surface waters, indicating a large retention of N in the basin. Although N deposition currently contributes much less than S to soil acidification in this area, it is possible that catchments receiving a high input of N may be unable to retain a large fraction of the N deposition over long periods. Copyright © 2016 Elsevier Ltd. All rights reserved.

Deepwater Program: Exploration and Research of Northern Gulf of Mexico Deepwater Natural and Artificial Hard Bottom Habitats with Emphasis on Coral Communities: Reefs, Rigs and Wrecks

DTIC Science & Technology

2010-01-01

Ocean Acidification on Coral Reefs and Other Marine Calcifiers: A Guide for...Roberts, J.M. & Guinotte, J.J. (2007) Corals in deep water: Will the unseen hand of ocean acidification destroy cold water ecosystems? Coral Reefs ...scleractinians from the NE Atlantic Ocean . Coral Reefs , 24(3), 514-522. Wang JL, Whitlock MC (2003) Estimating effective population size and migration rates

Roles of iron species and pH optimization on sewage sludge conditioning with Fenton's reagent and lime.

PubMed

Yu, Wenbo; Yang, Jiakuan; Shi, Yafei; Song, Jian; Shi, Yao; Xiao, Jun; Li, Chao; Xu, Xinyu; He, Shu; Liang, Sha; Wu, Xu; Hu, Jingping

2016-05-15

Conditioning sewage sludge with Fenton's reagent could effectively improve its dewaterability. However, drawbacks of conditioning with Fenton's reagent are requirement of acidic conditions to prevent iron precipitation and subsequent neutralization with alkaline additive to obtain the pH of the filtrate close to neutrality. In this study, roles of pH were thoroughly investigated in the acidification pretreatment, Fenton reaction, and the final filtrate after conditioning. Through the response surface methodology (RSM), the optimal dosages of H2SO4, Fe(2+), H2O2, and lime acted as a neutralizer were found to be 0 (no acidification), 47.9, 34.3 and 43.2 mg/g DS (dry solids). With those optimal doses, water content of the dewatered sludge cakes could be reduced to 55.8 ± 0.6 wt%, and pH of the final filtrate was 6.6 ± 0.2. Fenton conditioning without initial acidification can simplify the conditioning process and reduce the usage of lime. The Fe(3+) content in the sludge cakes showed a close correlation with the dewaterability of conditioned sludge, i.e., the water content of sludge cakes, SRF (specific resistance to filtration), CST (capillary suction time), bound water content, and specific surface area. It indicated that the coagulation by Fe(3+) species in Fenton reaction could play an important role, compared to traditional Fenton oxidation effect on sludge conditioning. Thus, a two-step mechanism of Fenton oxidation and Fe(III) coagulation was proposed in sewage sludge conditioning. The mechanisms include the following: (1) extracellular polymeric substances (EPS) were firstly degraded into dissolved organics by Fenton oxidation; (2) bound water was converted to free water due to degradation of EPS; (3) the sludge particles were disintegrated into small ones by oxidation; (4) Fe(3+) generated from Fenton reaction acted as a coagulant to agglomerate smaller sludge particles into larger dense particles with less bond water; (5) finally, the dewatered sludge cakes were obtained, with less small pores (1-10 nm) that contributed to water affinity, but with more large pores (>10 nm) that contributed to a permeable, rigid lattice structure. Morphology of the Fenton-conditioned sludge cake exhibited a porous structure. The estimated cost of the composite conditioner, Fenton's reagent and lime, is USD$ 43.8/t DS, which is less than that of ferric chloride and lime (USD$ 54/t DS). Furthermore, pH of the final filtrate using this composite conditioner is about 6.6. Comparatively, that using ferric chloride and lime is as high as 12.4. Copyright © 2016 Elsevier Ltd. All rights reserved.

Acidification of the gill cells of the shore crab Carcinus mediterraneus: Its physiological significance

NASA Astrophysics Data System (ADS)

Lucu, Č.; Siebers, D.

1995-03-01

In a preparation of isolated gills of the shore crab Carcinus mediterraneus perfused with dilute sea water (pH 8.1, 200 mM Na+) which was identical to the bathing solution of the gill, acidification of the collected perfusate was observed. Acidification was not affected by 10-4 M EIPA (5-[N-ethyl-N-isopropyl]amiloride), a strong inhibitor of Na+/H+ exchange. However, in the presence of 10-4 M acetazolamide, acidification was greatly blocked. The significant decrease of the acid load of the perfusate is considered to be a result of inhibition of the branchial intracellular carbonic anhydrase catalyzing the formation of H+ ions.

Preserving ground water samples with hydrochloric acid does not result in the formation of chloroform

USGS Publications Warehouse

Squillace, Paul J.; Pankow, James F.; Barbash, Jack E.; Price, Curtis V.; Zogorski, John S.

1999-01-01

Water samples collected for the determination of volatile organic compounds (VOCs) are often preserved with hydrochloric acid (HCl) to inhibit the biotransformation of the analytes of interest until the chemical analyses can he performed. However, it is theoretically possible that residual free chlorine in the HCl can react with dissolved organic carbon (DOC) to form chloroform via the haloform reaction. Analyses of 1501 ground water samples preserved with HCl from the U.S. Geological Survey's National Water-Quality Assessment Program indicate that chloroform was the most commonly detected VOC among 60 VOCs monitored. The DOC concentrations were not significantly larger in samples with detectable chloroform than in those with no delectable chloroform, nor was there any correlation between the concentrations of chloroform and DOC. Furthermore, chloroform was detected more frequently in shallow ground water in urban areas (28.5% of the wells sampled) than in agricultural areas (1.6% of the wells sampled), which indicates that its detection was more related to urban land-use activities than to sample acidification. These data provide strong evidence that acidification with HCl does not lead to the production of significant amounts of chloroform in ground water samples. To verify these results, an acidification study was designed to measure the concentrations of all trihalomethanes (THMs) that can form as a result of HCl preservation in ground water samples and to determine if ascorbic acid (C6H8O6) could inhibit this reaction if it did occur. This study showed that no THMs were formed as a result of HCl acidification, and that ascorbic acid had no discernible effect on the concentrations of THMs measured.

Ecosystem modeling of coastal acidification and hypoxia and structural uncertainties in the representation of sediment-water exchanges

EPA Science Inventory

Numerical ecosystem models of coastal acidification (CA) and hypoxia have been developed to synthesize current scientific understanding and provide predictions for nutrient management and policy. However, there is not a scientific consensus about the structure of these models an...

Long-term changes in the acidity of a dekalb forest soil in the mid-region of the Susquehanna River Watershed

Treesearch

Joy R. Robert; William E. Sharpe

1996-01-01

Forest soil acidification has been reported to result in reduced forest productivity and forest decline. Soil acidification and forest decline may trigger changes in nutrient cycling in forest ecosystems with important consequences for drainage water chemistry and aquatic biota.

Chemical and biological characteristics of Emerald Lake and the streams in its watershed and the responses of the lake and streams to acidic deposition. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Melack, J.M.; Cooper, S.D.; Jenkins, T.M.

1989-03-14

This report describes the results of field work conducted at Emerald Lake in Sequoia National Park during the period of 1983-88, with an emphasis on the effects of acid deposition on a high-elevation lake in the Sierra Nevada. Time-series data were collected for major ions, nutrients, trace metals, chlorophyll, zooplankton and zoobenthos. Mass balances were calculated for major solutes in the lake, including analysis of the inflows and major solutes in the lake, including analysis of the inflows and outflow from the lake. The ecology and population dynamics of the resident population of brook trout were studied in detail. Biologicalmore » surveys indicated the presence of the Pacific tree frog in small ponds in the vicinity of Emerald Lake. Experimental acidification of large bags in the lake was used to develop dose-response relationships for the major zooplankton species, especially Daphnia. The conclusion of the research to date is that Emerald Lake is not currently showing serious chemical or biological effects of acidification. Acid-sensitive animals are found in the lake and associated streams. The surface waters of the Emerald Basin are extremely dilute and ANC-generating processes in the lake are small compared to that of the watershed. Acidic episodes have been recorded. If these episodes were to increase, the surface waters and the biological populations could be readily affected.« less

Speleothem records of acid sulphate deposition and organic carbon mobilisation

NASA Astrophysics Data System (ADS)

Wynn, Peter; Fairchild, Ian; Bourdin, Clement; Baldini, James; Muller, Wolfgang; Hartland, Adam; Bartlett, Rebecca

2017-04-01

Dramatic increases in measured surface water DOC in recent decades have been variously attributed to either temperature rise, or destabilisation of long-term soil carbon pools following sulphur peak emissions status. However, whilst both drivers of DOC dynamics are plausible, they remain difficult to test due to the restricted nature of the available records of riverine DOC flux (1978 to present), and the limited availability of SO2 emissions inventory data at the regional scale. Speleothems offer long term records of both sulphur and carbon. New techniques to extract sulphur concentrations and isotopes from speleothem calcite have enabled archives of pollution history and environmental acidification to be reconstructed. Due to the large dynamic range in sulphur isotopic values from end member sources (marine aerosol +21 ‰ to continental biogenic emissions -30 ‰) and limited environmental fractionation under oxidising conditions, sulphur isotopes form an ideal tracer of industrial pollution and environmental acidification in the palaeo-record. We couple this acidification history to the carbon record, using organic matter fluorescence and trace metals. Trace metal ratios and abundance can be used to infer the type and size of organic ligand and are therefore sensitive to changes in temperature as a driver of organic carbon processing and biodegradation. This allows fluorescent properties and ratios of trace metals in speleothem carbonate to be used to represent both the flux of organic carbon into the cave as well as the degradation pathway. Here we present some of the first results of this work, exploring sulphur acidification as a mechanistic control on carbon solubility and export throughout the twentieth century.

DMS emissions from Sphagnum-dominated wetlands

NASA Technical Reports Server (NTRS)

Hines, Mark E.; Demello, William Zamboni; Bayley, Suzanne E.

1992-01-01

The role of terrestrial sources of biogenic S and their effect on atmospheric chemistry remain as major unanswered questions in our understanding of the natural S cycle. The role of northern wetlands as sources and sinks of gaseous S was investigated by measuring rates of S gas exchange as a function of season, hydrologic conditions, and gradients in trophic status. Experiments were conducted in wetlands in New Hampshire (NH), and in Mire 239, a poor fen at the Experimental Lakes Area (ELA) in Ontario. Emissions were determined using Teflon enclosures, gas cryotrapping methods, and GC with flame photometric detection. Emissions of DMS dominated fluxes. In NH, DMS fluxes were greater than 1.6 micromol/m(sup -2)d(sup -1) in early summer, 1989 when temperatures were warm and the water table was approximately 5 cm below the surface. These rates are several-fold faster than average oceanic rates of DMS emission. A rapid drop in the water table resulted in a 6-fold decrease in DMS emissions in late July. In 1990, a new beaver dam kept water levels above the surface and S emissions were much lower than during 1989. The elimination of the beaver and a drop in the water table in August produced a rapid increase in S gas emissions. Emissions of DMS were highest in the most oligotrophic areas. Mire 239 (ELA) was irrigated with sulfuric and nitric acids to simulate acid rain. S emissions were determined before and after an acidification event in control and experimental areas in both minerotrophic and oligotrophic regions. Emissions of DMS were higher in the acidified areas compared to unacidified controls. Emissions were also much higher in the oligotrophic regions compared to the minerotrophic ones. Despite the wide differences in S gas fluxes (20-fold), it was difficult to determine whether acidification or variations in trophic status was not responsible for differences in S gas emissions. DMS emitted into the atmosphere was not derived from the water table but originated in peat in the unsaturated zone.

Numerical study of chemical reactions in a surface microdischarge tube with mist flow based on experiment

NASA Astrophysics Data System (ADS)

Shibata, T.; Nishiyama, H.

2014-03-01

Recently, a water treatment method of spraying solution into a discharge region has been developed and shows high energy efficiency. In this study, a simulation model of a water treatment method using a surface microdischarge (SMD) tube with mist flow is proposed for further understanding the detailed chemical reactions. Our model has three phases (plasma, gas and liquid) and three simulation steps. The carrier gas is humid air including 2% or 3% water vapour. The chemical species diffusion characteristics in the SMD tube and the concentrations in a droplet are clarified in a wide pH interval. The simulation results show that the chemical species generated on the SMD tube inner wall are diffused to the central axis and dissolved into fine droplets. Especially, OH radicals dissolve into droplets a few mm away from the SMD tube wall because of acidification of the droplets. Furthermore, the hydrogen peroxide density, which is the most important indicator of a radical reaction in water, is influenced by the initial solution pH. This pH dependence results from ozone self-decomposition in water.

Interaction effects between sender and receiver processes in indirect transmission of Campylobacter jejuni between broilers

PubMed Central

2012-01-01

Background Infectious diseases in plants, animals and humans are often transmitted indirectly between hosts (or between groups of hosts), i.e. via some route through the environment instead of via direct contacts between these hosts. Here we study indirect transmission experimentally, using transmission of Campylobacter jejuni (C. jejuni) between spatially separated broilers as a model system. We distinguish three stages in the process of indirect transmission; (1) an infectious “sender” excretes the agent, after which (2) the agent is transported via some route to a susceptible “receiver”, and subsequently (3) the receiver becomes colonised by the agent. The role of the sender and receiver side (stage 1 and stage 3) was studied here by using acidification of the drinking water as a modulation mechanism. Results In the experiment one control group and three treatment groups were monitored for the presence of C. jejuni by taking daily cloacal swabs. The three treatments consisted of acidification of the drinking water of the inoculated animals (the senders), acidification of the drinking water of the susceptible animals (the receivers) or acidification of the drinking water of both inoculated and susceptible animals. In the control group 12 animals got colonised out of a possible 40, in each treatment groups 3 animals out of a possible 40 were found colonised with C. jejuni. Conclusions The results of the experiments show a significant decrease in transmission rate (β) between the control groups and treatment groups (p < 0.01 for all groups) but not between different treatments; there is a significant negative interaction effect when both the sender and the receiver group receive acidified drinking water (p = 0.01). This negative interaction effect could be due to selection of bacteria already at the sender side thereby diminishing the effect of acidification at the receiver side. PMID:22831274

The reef-building coral Siderastrea siderea exhibits parabolic responses to ocean acidification and warming.

PubMed

Castillo, Karl D; Ries, Justin B; Bruno, John F; Westfield, Isaac T

2014-12-22

Anthropogenic increases in atmospheric CO2 over this century are predicted to cause global average surface ocean pH to decline by 0.1-0.3 pH units and sea surface temperature to increase by 1-4°C. We conducted controlled laboratory experiments to investigate the impacts of CO2-induced ocean acidification (pCO2 = 324, 477, 604, 2553 µatm) and warming (25, 28, 32°C) on the calcification rate of the zooxanthellate scleractinian coral Siderastrea siderea, a widespread, abundant and keystone reef-builder in the Caribbean Sea. We show that both acidification and warming cause a parabolic response in the calcification rate within this coral species. Moderate increases in pCO2 and warming, relative to near-present-day values, enhanced coral calcification, with calcification rates declining under the highest pCO2 and thermal conditions. Equivalent responses to acidification and warming were exhibited by colonies across reef zones and the parabolic nature of the corals' response to these stressors was evident across all three of the experiment's 30-day observational intervals. Furthermore, the warming projected by the Intergovernmental Panel on Climate Change for the end of the twenty-first century caused a fivefold decrease in the rate of coral calcification, while the acidification projected for the same interval had no statistically significant impact on the calcification rate-suggesting that ocean warming poses a more immediate threat than acidification for this important coral species.

The reef-building coral Siderastrea siderea exhibits parabolic responses to ocean acidification and warming

PubMed Central

Castillo, Karl D.; Ries, Justin B.; Bruno, John F.; Westfield, Isaac T.

2014-01-01

Anthropogenic increases in atmospheric CO2 over this century are predicted to cause global average surface ocean pH to decline by 0.1–0.3 pH units and sea surface temperature to increase by 1–4°C. We conducted controlled laboratory experiments to investigate the impacts of CO2-induced ocean acidification (pCO2 = 324, 477, 604, 2553 µatm) and warming (25, 28, 32°C) on the calcification rate of the zooxanthellate scleractinian coral Siderastrea siderea, a widespread, abundant and keystone reef-builder in the Caribbean Sea. We show that both acidification and warming cause a parabolic response in the calcification rate within this coral species. Moderate increases in pCO2 and warming, relative to near-present-day values, enhanced coral calcification, with calcification rates declining under the highest pCO2 and thermal conditions. Equivalent responses to acidification and warming were exhibited by colonies across reef zones and the parabolic nature of the corals' response to these stressors was evident across all three of the experiment's 30-day observational intervals. Furthermore, the warming projected by the Intergovernmental Panel on Climate Change for the end of the twenty-first century caused a fivefold decrease in the rate of coral calcification, while the acidification projected for the same interval had no statistically significant impact on the calcification rate—suggesting that ocean warming poses a more immediate threat than acidification for this important coral species. PMID:25377455

Impacts of ocean acidification on the carbonate system at the sediment-water interface: a case-study in the NW Mediterranean Sea

NASA Astrophysics Data System (ADS)

Rassmann, Jens; Lansard, Bruno; Gazeau, Frédéric; Grenz, Christian; Alliouane, Samir; Petit, Franck; Pozzato, Lara; Bombled, Bruno; Rabouille, Christophe

2016-04-01

According to common predictions, carbon dioxide (CO2) uptake from the atmosphere into the oceans will decrease the average pH of seawater by 0.06-0.32 pH units by 2100. Ocean acidification alters chemical equilibria in seawater and thus potentially impacts marine ecosystem structure and functioning. Shelf regions play a key role for an important fraction of marine life and represent an important part of the global carbon cycle. Due to shallow water depth, chemistry in the water column is strongly coupled with biogeochemistry in the sediments. The aim of the present work is to investigate the impact of ocean acidification on carbonate chemistry. It focuses especially on exchange fluxes of dissolved inorganic carbon (DIC), total alkalinity (TA) and calcium through the sediment-water interface, and its impact on calcium carbonate precipitation or dissolution. For this purpose, sediment cores were incubated ex situ with an open flow of CO2 enriched seawater for 22 days (pHT=7,4, pH reported on the total proton scale). In parallel, sediment cores were incubated as a control with untreated seawater. Incubations took place in a water bath in a dark room with controlled temperature (14°C). Oxygen and pH microprofiles were recorded in the top first mm of the sediment during the whole experiment every 3 days. On 7 occasions, cores were isolated and incubated for 12 hours to estimate fluxes of DIC, TA, oxygen and nutrients. Porewater profiles of DIC, TA, calcium and nutrients were analyzed before and after incubation. On the solid phase, the content of particulate organic carbon, the C:N ratio and its isotopic δ15N and δ13C signature have been determined. In addition, total carbon contents have been measured and X-Ray diffraction was used to look for phase shifts between calcite and aragonite. A net decrease of pH was observed in the upper sediment layers, as well as an increase of DIC and TA pore water concentrations. The acidified cores showed higher DIC and TA exchange fluxes during the incubations in isolation, whereas oxygen exchange fluxes were independent of pH. Significant changes in the solid phase of the sediments could not be identified and the calcium pore water concentrations seemed not to be affected by acidification of the overlying waters during the given time scale. These results are put in the framework of coastal ocean acidification and are used to understand how the acidification changes the carbonate chemistry in the pore waters and constrain dissolution/precipitation of calcium carbonate.

Warming and surface ocean acidification over the last deglaciation: implications for foraminiferal assemblages

NASA Astrophysics Data System (ADS)

Dyez, K. A.; Hoenisch, B.; deMenocal, P. B.

2017-12-01

Although plankton drift with ocean currents, their presence and relative abundance varies across latitudes and environmental seawater conditions (e.g. temperature, pH, salinity). While earlier studies have focused on temperature as the primary factor for determining the regional species composition of planktic foraminiferal communities, evidence has recently been presented that foraminiferal shell thickness varies with ocean pH, and it remains unclear whether ongoing ocean acidification will cause ecological shifts within this plankton group. The transition from the last glacial maximum (LGM; 19,000-23,000 years B.P.) to the late Holocene (0-5,000 years B.P.) was characterized by both warming and acidification of the surface ocean, and thus provides an opportunity to study ecosystem shifts in response to these environmental changes. Here we provide new δ11B, Mg/Ca, and δ18O measurements from a suite of global sediment cores spanning this time range. We use these geochemical data to reconstruct ocean temperature, pH and salinity and pair the new data with previously published analyses of planktic foraminifera assemblages to study the respective effects of ocean warming and acidification on the foraminiferal habitat. At most open-ocean sample locations, our proxies indicate warming and acidification similar to previously published estimates, but in some marginal seas and coastal locations pH changes little between over the glacial termination. At face value, these observations suggest that warming is generally more important for ecosystem changes than acidification, at least over the slow rates of warming and ocean acidification in this time period. While geochemical data collection is being completed, we aim to include these data in an ecological model of foraminiferal habitat preferences.

Divergent ecosystem responses within a benthic marine community to ocean acidification.

PubMed

Kroeker, Kristy J; Micheli, Fiorenza; Gambi, Maria Cristina; Martz, Todd R

2011-08-30

Ocean acidification is predicted to impact all areas of the oceans and affect a diversity of marine organisms. However, the diversity of responses among species prevents clear predictions about the impact of acidification at the ecosystem level. Here, we used shallow water CO(2) vents in the Mediterranean Sea as a model system to examine emergent ecosystem responses to ocean acidification in rocky reef communities. We assessed in situ benthic invertebrate communities in three distinct pH zones (ambient, low, and extreme low), which differed in both the mean and variability of seawater pH along a continuous gradient. We found fewer taxa, reduced taxonomic evenness, and lower biomass in the extreme low pH zones. However, the number of individuals did not differ among pH zones, suggesting that there is density compensation through population blooms of small acidification-tolerant taxa. Furthermore, the trophic structure of the invertebrate community shifted to fewer trophic groups and dominance by generalists in extreme low pH, suggesting that there may be a simplification of food webs with ocean acidification. Despite high variation in individual species' responses, our findings indicate that ocean acidification decreases the diversity, biomass, and trophic complexity of benthic marine communities. These results suggest that a loss of biodiversity and ecosystem function is expected under extreme acidification scenarios.

The Impact of Ocean Acidification on the Functional Morphology of Foraminifera

PubMed Central

Khanna, Nikki; Godbold, Jasmin A.; Austin, William E. N.; Paterson, David M.

2013-01-01

Culturing experiments were performed on sediment samples from the Ythan Estuary, N. E. Scotland, to assess the impacts of ocean acidification on test surface ornamentation in the benthic foraminifer Haynesina germanica. Specimens were cultured for 36 weeks at either 380, 750 or 1000 ppm atmospheric CO2. Analysis of the test surface using SEM imaging reveals sensitivity of functionally important ornamentation associated with feeding to changing seawater CO2 levels. Specimens incubated at high CO2 levels displayed evidence of shell dissolution, a significant reduction and deformation of ornamentation. It is clear that these calcifying organisms are likely to be vulnerable to ocean acidification. A reduction in functionally important ornamentation could lead to a reduction in feeding efficiency with consequent impacts on this organism's survival and fitness. PMID:24358253

Multiple stresses from a single agent: Diverse responses to the experimental acidification of Little Rock Lake, Wisconsin

USGS Publications Warehouse

Frost, T.M.; Montz, P.K.; Kratz, T.K.; Badillo, T.; Brezonik, P.L.; Gonzalez, M.J.; Rada, R.G.; Watras, C.J.; Webster, K.E.; Wiener, J.G.; Williamson, C.E.; Morris, D.P.

1999-01-01

A single stress, acidification with sulfuric acid, was applied to Little Rack Lake in a whole-ecosystem manipulation. We documented a wide range of responses to the acidification, including increases in the concentrations of various chemicals, shifts in microbial processes and a major increase in water clarity to UV-B radiation. Each of these changes could in itself be considered as a separate ecosystem stress that is distinct from the intended manipulation. Acidification in Little Rock Lake was accompanied by a number of substantial changes in the occurrence of organisms. A series of detailed investigations indicates that the mechanisms underlying these organismal changes are varied but cannot usually be tied to the direct effects of acidification. Overall, our results demonstrate how multiple stresses can arise from a single agent operating on an ecosystem and suggest that singly operating stresses may actually be quite rare.

Influence of storage conditions on aluminum concentrations in serum, dialysis fluid, urine, and tap water.

PubMed

Wilhelm, M; Ohnesorge, F K

1990-01-01

The influence of storage temperature, vessel type, and treatment on alterations of aluminum (Al) concentrations in serum, urine, and dialysis fluid samples was studied at three different concentrations for each sample over an 18-month period. Furthermore, the influence of acidification on Al levels in tap water, urine, and dialysis fluid samples was studied over a four-month period. Al was measured by atomic absorption spectrometry. Sample storage in glass vessels was unsuitable, whereas only minor alterations of Al levels were observed with storage in polypropylene tubes, polystyrene tubes, and Monovettes. By using appropriate plastic containers, acid washing of the vessels showed no improvement. Frozen storage was superior compared with 4 degrees C, whereas storage at -80 degrees C offered no advantage compared with storage at -20 degrees C. Acidification of tap water samples was necessary to stabilize Al levels during storage. No striking effect of acidification on Al levels in urine and dialysis fluid samples was found. It is concluded that longterm storage of serum, urine, tap water, and dialysis fluid samples is possible if appropriate conditions are used.

Ocean acidification and its potential effects on marine ecosystems.

PubMed

Guinotte, John M; Fabry, Victoria J

2008-01-01

Ocean acidification is rapidly changing the carbonate system of the world oceans. Past mass extinction events have been linked to ocean acidification, and the current rate of change in seawater chemistry is unprecedented. Evidence suggests that these changes will have significant consequences for marine taxa, particularly those that build skeletons, shells, and tests of biogenic calcium carbonate. Potential changes in species distributions and abundances could propagate through multiple trophic levels of marine food webs, though research into the long-term ecosystem impacts of ocean acidification is in its infancy. This review attempts to provide a general synthesis of known and/or hypothesized biological and ecosystem responses to increasing ocean acidification. Marine taxa covered in this review include tropical reef-building corals, cold-water corals, crustose coralline algae, Halimeda, benthic mollusks, echinoderms, coccolithophores, foraminifera, pteropods, seagrasses, jellyfishes, and fishes. The risk of irreversible ecosystem changes due to ocean acidification should enlighten the ongoing CO(2) emissions debate and make it clear that the human dependence on fossil fuels must end quickly. Political will and significant large-scale investment in clean-energy technologies are essential if we are to avoid the most damaging effects of human-induced climate change, including ocean acidification.

Hypoxia and acidification have additive and synergistic negative effects on the growth, survival, and metamorphosis of early life stage bivalves.

PubMed

Gobler, Christopher J; DePasquale, Elizabeth L; Griffith, Andrew W; Baumann, Hannes

2014-01-01

Low oxygen zones in coastal and open ocean ecosystems have expanded in recent decades, a trend that will accelerate with climatic warming. There is growing recognition that low oxygen regions of the ocean are also acidified, a condition that will intensify with rising levels of atmospheric CO2. Presently, however, the concurrent effects of low oxygen and acidification on marine organisms are largely unknown, as most prior studies of marine hypoxia have not considered pH levels. We experimentally assessed the consequences of hypoxic and acidified water for early life stage bivalves (bay scallops, Argopecten irradians, and hard clams, Mercenaria mercenaria), marine organisms of significant economic and ecological value and sensitive to climate change. In larval scallops, experimental and naturally-occurring acidification (pH, total scale  = 7.4-7.6) reduced survivorship (by >50%), low oxygen (30-50 µM) inhibited growth and metamorphosis (by >50%), and the two stressors combined produced additively negative outcomes. In early life stage clams, however, hypoxic waters led to 30% higher mortality, while acidified waters significantly reduced growth (by 60%). Later stage clams were resistant to hypoxia or acidification separately but experienced significantly (40%) reduced growth rates when exposed to both conditions simultaneously. Collectively, these findings demonstrate that the consequences of low oxygen and acidification for early life stage bivalves, and likely other marine organisms, are more severe than would be predicted by either individual stressor and thus must be considered together when assessing how ocean animals respond to these conditions both today and under future climate change scenarios.

Effects of Ocean Acidification on Juvenile Red King Crab (Paralithodes camtschaticus) and Tanner Crab (Chionoecetes bairdi) Growth, Condition, Calcification, and Survival

PubMed Central

Long, William Christopher; Swiney, Katherine M.; Harris, Caitlin; Page, Heather N.; Foy, Robert J.

2013-01-01

Ocean acidification, a decrease in the pH in marine waters associated with rising atmospheric CO2 levels, is a serious threat to marine ecosystems. In this paper, we determine the effects of long-term exposure to near-future levels of ocean acidification on the growth, condition, calcification, and survival of juvenile red king crabs, Paralithodes camtschaticus, and Tanner crabs, Chionoecetes bairdi. Juveniles were reared in individual containers for nearly 200 days in flowing control (pH 8.0), pH 7.8, and pH 7.5 seawater at ambient temperatures (range 4.4–11.9 °C). In both species, survival decreased with pH, with 100% mortality of red king crabs occurring after 95 days in pH 7.5 water. Though the morphology of neither species was affected by acidification, both species grew slower in acidified water. At the end of the experiment, calcium concentration was measured in each crab and the dry mass and condition index of each crab were determined. Ocean acidification did not affect the calcium content of red king crab but did decrease the condition index, while it had the opposite effect on Tanner crabs, decreasing calcium content but leaving the condition index unchanged. This suggests that red king crab may be able to maintain calcification rates, but at a high energetic cost. The decrease in survival and growth of each species is likely to have a serious negative effect on their populations in the absence of evolutionary adaptation or acclimatization over the coming decades. PMID:23593357

Composition of fish communities in relation to stream acidification and habitat in the Neversink River, New York

USGS Publications Warehouse

Baldigo, Barry P.; Lawrence, G.B.

2000-01-01

The effects of acidification in lotic systems are not well documented. Spatial and temporal variability of habitat and water quality complicate the evaluation of acidification effects in streams and river. The Neversink River in the Catskill Mountains of southeastern New York, the tributaries of which vary from well buffered to severely acidified, provided an opportunity to investigate the external and magnitude of acidification effects on fish communities of headwater systems. Composition of fish communities, water quality, stream hydrology, stream habitat, and physiographic factors were characterized from 1991 to 1995 at 16 first- to fourth-order sites in the basin. Correlation and regression analyses were used to develop empirical models and to assess the relations among fish species richness, total fish density, and total biomass and environmental variables. Chronic and episodic acidification and elevated concentrations of inorganic monomeric aluminum were common, and fish populations were rare or absent from several sites in the upper reaches of the basin; as many as six fish species were collected from sites in the lower reaches of the basin. Species distribution and species richness were most highly related to stream pH, acid-neutralizing capacity (ANC), inorganic monomeric aluminum (Al(im)), calcium (Ca)2+, and potassium (K)+ concentrations, site elevation, watershed drainage area, and water temperature. Fish density was most highly related to stream pH, Al(im), ANC, K+, Ca2+, and magnesium (Mg)2+ concentrations. Fish biomass, unlike species richness and fish density, was most highly related to physical habitat characteristics, water temperature, and concentrations of Mg2+ and silicon. Acidity characteristics were of secondary importance to fish biomass at all but the most severely acidified sites. Our results indicate that (1) the total biomass of fish communities was not seriously affected at moderately to strongly acidified sites; (2) species richness and total density of fish were adversely affected at strongly to severely acidified sites; and (3) possible changes in competitive interactions may mitigate negative effects of acidification on fish communities in parts of the Neversink River Basin.

Organic acid modeling and model validation: Workshop summary. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sullivan, T.J.; Eilers, J.M.

1992-08-14

A workshop was held in Corvallis, Oregon on April 9--10, 1992 at the offices of E&S Environmental Chemistry, Inc. The purpose of this workshop was to initiate research efforts on the entitled ``Incorporation of an organic acid representation into MAGIC (Model of Acidification of Groundwater in Catchments) and testing of the revised model using Independent data sources.`` The workshop was attended by a team of internationally-recognized experts in the fields of surface water acid-bass chemistry, organic acids, and watershed modeling. The rationale for the proposed research is based on the recent comparison between MAGIC model hindcasts and paleolimnological inferences ofmore » historical acidification for a set of 33 statistically-selected Adirondack lakes. Agreement between diatom-inferred and MAGIC-hindcast lakewater chemistry in the earlier research had been less than satisfactory. Based on preliminary analyses, it was concluded that incorporation of a reasonable organic acid representation into the version of MAGIC used for hindcasting was the logical next step toward improving model agreement.« less

Organic acid modeling and model validation: Workshop summary

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sullivan, T.J.; Eilers, J.M.

1992-08-14

A workshop was held in Corvallis, Oregon on April 9--10, 1992 at the offices of E S Environmental Chemistry, Inc. The purpose of this workshop was to initiate research efforts on the entitled Incorporation of an organic acid representation into MAGIC (Model of Acidification of Groundwater in Catchments) and testing of the revised model using Independent data sources.'' The workshop was attended by a team of internationally-recognized experts in the fields of surface water acid-bass chemistry, organic acids, and watershed modeling. The rationale for the proposed research is based on the recent comparison between MAGIC model hindcasts and paleolimnological inferencesmore » of historical acidification for a set of 33 statistically-selected Adirondack lakes. Agreement between diatom-inferred and MAGIC-hindcast lakewater chemistry in the earlier research had been less than satisfactory. Based on preliminary analyses, it was concluded that incorporation of a reasonable organic acid representation into the version of MAGIC used for hindcasting was the logical next step toward improving model agreement.« less

Hydrogeochemie von Eisenausfällungen an Grundwasseraustritten der Abraumkippe Berrenrath (Rheinisches Braunkohlenrevier)

NASA Astrophysics Data System (ADS)

Lenk, Stephan; Wisotzky, Frank; Cremer, Nils

2013-03-01

Groundwater at the abandoned lignite mine in Berrenrath (Germany) is acidic and highly mineralised. Average iron concentrations of 588 mg/l indicate a high potential for acidification. Furthermore, investigations revealed a complete depletion of the carbonate buffer capacity (CaCO3 and HCO3-) during chemical groundwater evolution. Over the next few decades, no decrease of dissolved pyrite oxidation products is expected. On the contrary, within the drainage ditches at the edges of the dump, an intense precipitation of iron oxides is occurring. However, despite oxygen saturation, precipitation of iron oxides is incomplete due to strong acidification of the surface water (pH<3.0). The main contamination of the iron sludge is caused by high nickel concentrations. This element is only loosely bound to the iron oxides and is easily mobilised. Because of high nickel- and sulphate-concentrations, the excavated material has to be deposited in a controlled landfill (German dump category of 2 to 3).

Acid rain and its ecological consequences.

PubMed

Singh, Anita; Agrawal, Madhoolika

2008-01-01

Acidification of rain-water is identified as one of the most serious environmental problems of transboundary nature. Acid rain is mainly a mixture of sulphuric and nitric acids depending upon the relative quantities of oxides of sulphur and nitrogen emissions. Due to the interaction of these acids with other constituents of the atmosphere, protons are released causing increase in the soil acidity Lowering of soil pH mobilizes and leaches away nutrient cations and increases availability of toxic heavy metals. Such changes in the soil chemical characteristics reduce the soil fertility which ultimately causes the negative impact on growth and productivity of forest trees and crop plants. Acidification of water bodies causes large scale negative impact on aquatic organisms including fishes. Acidification has some indirect effects on human health also. Acid rain affects each and every components of ecosystem. Acid rain also damages man-made materials and structures. By reducing the emission of the precursors of acid rain and to some extent by liming, the problem of acidification of terrestrial and aquatic ecosystem has been reduced during last two decades.

Computational Elucidation of a Role That Brønsted Acidification of the Lewis Acid-Bound Water Might Play in the Hydrogenation of Carbonyl Compounds with H2 in Lewis Basic Solvents.

PubMed

Heshmat, Mojgan; Privalov, Timofei

2017-08-25

Brønsted acidification of water by Lewis acid (LA) complexation is one of the fundamental principles in chemistry. Using transition-state calculations (TS), herein we investigate the role that Brønsted acidification of the LA-bound water might play in the mechanism of the hydrogenation of carbonyl compounds in Lewis basic solvents under non-anhydrous conditions. The potential energy scans and TS calculations were carried out with a series of eight borane LAs as well as the commonly known strong LA AlCl 3 in 1,4-dioxane or THF as Lewis basic solvents. Our molecular model consists of the dative LA-water adduct with hydrogen bonds to acetone and a solvent molecule plus one additional solvent molecule that participates is the TS structure describing the cleavage of H 2 at acetone's carbonyl carbon atom. In all the molecular models applied here, acetone (O=CMe 2 ) is the archetypical carbonyl substrate. We demonstrate that Brønsted acidification of the LA-bound water can indeed lower the barrier height of the solvent-involving H 2 -cleavage at the acetone's carbonyl carbon atom. This is significant because at present it is believed that the mechanism of the herein considered reaction is described by the same mechanism regardless of whether the reaction conditions are strictly anhydrous or non-anhydrous. Our results offer an alternative to this belief that warrants consideration and further study. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

A process for producing lignin and volatile compounds from hydrolysis liquor.

PubMed

Khazraie, Tooran; Zhang, Yiqian; Tarasov, Dmitry; Gao, Weijue; Price, Jacquelyn; DeMartini, Nikolai; Hupa, Leena; Fatehi, Pedram

2017-01-01

Hot water hydrolysis process is commercially applied for treating wood chips prior to pulping or wood pellet production, while it produces hydrolysis liquor as a by-product. Since the hydrolysis liquor is dilute, the production of value-added materials from it would be challenging. In this study, acidification was proposed as a viable method to extract (1) furfural and acetic acid from hot water hydrolysis liquor and (2) lignin compounds from the liquor. The thermal properties of the precipitates made from the acidification of hydrolysis liquor confirmed the volatile characteristics of precipitates. Membrane dialysis was effective in removing inorganic salts associated with lignin compounds. The purified lignin compounds had a glass transition temperature (Tg) of 180-190 °C, and were thermally stable. The results confirmed that lignin compounds present in hot water hydrolysis liquor had different characteristics. The acidification of hydrolysis liquor primarily removed the volatile compounds from hydrolysis liquor. Based on these results, a process for producing purified lignin and precipitates of volatile compounds was proposed.

The consequences of human-driven ocean acidification for marine life.

PubMed

Doney, Scott

2009-05-08

Rising atmospheric carbon dioxide is causing a wholesale shift in surface seawater chemistry, potentially threatening many marine organisms that form shells and skeletons from calcium carbonate. Recent papers suggest that the biological consequences of ocean acidification already may be underway and may be more complex, nuanced and widespread than previously thought.

Tidal downwelling and implications for the carbon biogeochemistry of cold-water corals in relation to future ocean acidification and warming.

PubMed

Findlay, Helen S; Artioli, Yuri; Moreno Navas, Juan; Hennige, Sebastian J; Wicks, Laura C; Huvenne, Veerle A I; Woodward, E Malcolm S; Roberts, J Murray

2013-09-01

Cold-water coral (CWC) reefs are recognized as ecologically and biologically significant areas that generate habitats and diversity. The interaction between hydrodynamics and CWCs has been well studied at the Mingulay Reef Complex, a relatively shallow area of reefs found on the continental shelf off Scotland, UK. Within 'Mingulay Area 01' a rapid tidal downwelling of surface waters, brought about as an internal wave, is known to supply warmer, phytoplankton-rich waters to corals growing on the northern flank of an east-west trending seabed ridge. This study shows that this tidal downwelling also causes short-term perturbations in the inorganic carbon (CT ) and nutrient dynamics through the water column and immediately above the reef. Over a 14 h period, corresponding to one semi-diurnal tidal cycle, seawater pH overlying the reef varied by ca. 0.1 pH unit, while pCO2 shifted by >60 μatm, a shift equivalent to a ca. 25 year jump into the future, with respect to atmospheric pCO2 . During the summer stratified period, these downwelling events result in the reef being washed over with surface water that has higher pH, is warmer, nutrient depleted, but rich in phytoplankton-derived particles compared to the deeper waters in which the corals sit. Empirical observations, together with outputs from the European Regional Shelf Sea Ecosystem Model, demonstrate that the variability that the CWC reefs experience changes through the seasons and into the future. Hence, as ocean acidification and warming increase into the future, the downwelling event specific to this site could provide short-term amelioration of corrosive conditions at certain times of the year; however, it could additionally result in enhanced detrimental impacts of warming on CWCs. Natural variability in the CT and nutrient conditions, as well as local hydrodynamic regimes, must be accounted for in any future predictions concerning the responses of marine ecosystems to climate change. © 2013 John Wiley & Sons Ltd.

Inverse Modeling of Water-Rock-CO2 Batch Experiments: Potential Impacts on Groundwater Resources at Carbon Sequestration Sites.

PubMed

Yang, Changbing; Dai, Zhenxue; Romanak, Katherine D; Hovorka, Susan D; Treviño, Ramón H

2014-01-01

This study developed a multicomponent geochemical model to interpret responses of water chemistry to introduction of CO2 into six water-rock batches with sedimentary samples collected from representative potable aquifers in the Gulf Coast area. The model simulated CO2 dissolution in groundwater, aqueous complexation, mineral reactions (dissolution/precipitation), and surface complexation on clay mineral surfaces. An inverse method was used to estimate mineral surface area, the key parameter for describing kinetic mineral reactions. Modeling results suggested that reductions in groundwater pH were more significant in the carbonate-poor aquifers than in the carbonate-rich aquifers, resulting in potential groundwater acidification. Modeled concentrations of major ions showed overall increasing trends, depending on mineralogy of the sediments, especially carbonate content. The geochemical model confirmed that mobilization of trace metals was caused likely by mineral dissolution and surface complexation on clay mineral surfaces. Although dissolved inorganic carbon and pH may be used as indicative parameters in potable aquifers, selection of geochemical parameters for CO2 leakage detection is site-specific and a stepwise procedure may be followed. A combined study of the geochemical models with the laboratory batch experiments improves our understanding of the mechanisms that dominate responses of water chemistry to CO2 leakage and also provides a frame of reference for designing monitoring strategy in potable aquifers.

Collection to Archival: A Data Management Strategy for the Ocean Acidification Community

NASA Astrophysics Data System (ADS)

Burger, E. F.; Smith, K. M.; Parsons, A. R.; Wanninkhof, R. H.; O'Brien, K.; Barbero, L.; Schweitzer, R.; Manke, A.

2014-12-01

Recently new data collection platforms, many of them autonomous mobile platforms, have added immensely to the data volume the Ocean Acidification community is dealing with. This is no exception with NOAA's Pacific Marine Environmental Laboratory (PMEL) Ocean Acidification (OA) effort. Collaboration between the PMEL Carbon group and the PMEL Science Data Integration group to manage local data has spawned the development of a data management strategy that covers the data lifecycle from collection to analysis to quality control to archival. The proposed software and workflow will leverage the successful data management framework pioneered by the Surface Ocean CO2 Atlas (SOCAT) project, but customized for Ocean Acidification requirements. This presentation will give a brief overview of the data management framework that will be implemented for Ocean Acidification data that are collected by PMEL scientists. We will also be discussing our plans to leverage this system to build an east coast ocean acidification management system at NOAA's Atlantic Oceanographic and Meteorological Laboratory (AOML), as well as a national OA management system at NOAA's National Oceanographic Data Center (NODC).

Carbon Cycle Model of a Hawaiian Barrier Reef under Rising Ocean Acidification and Temperature Conditions of the Anthropocene

NASA Astrophysics Data System (ADS)

Drupp, P. S.; Mackenzie, F. T.; De Carlo, E. H.; Guidry, M.

2015-12-01

A CO2-carbonic acid system biogeochemical box model (CRESCAM, Coral Reef and Sediment Carbonate Model) of the barrier reef flat in Kaneohe Bay, Hawai'i was developed to determine how increasing temperature and dissolved inorganic carbon (DIC) content of open ocean source waters, resulting from rising anthropogenic CO2 emissions and ocean acidification, affect the CaCO3budget of coral reef ecosystems. CRESCAM consists of 17 reservoirs and 59 fluxes, including a surface water column domain, a two-layer permeable sediment domain, and a coral framework domain. Physical, chemical, and biological processes such as advection, carbonate precipitation/dissolution, and net ecosystem production and calcification were modeled. The initial model parameters were constrained by experimental and field data from previous coral reef studies, mostly in Kaneohe Bay over the past 50 years. The field studies include data collected by our research group for both the water column and sediment-porewater system.The model system, initially in a quasi-steady state condition estimated for the early 21st century, was perturbed using future projections to the year 2100 of the Anthropocene of atmospheric CO2 ­concentrations, temperature, and source water DIC. These perturbations were derived from the most recent (2013) IPCC's Representative Concentration Pathway (RCP) scenarios, which predict CO2 atmospheric concentrations and temperature anomalies out to 2100. A series of model case studies were also performed whereby one or more parameters (e.g., coral calcification response to declining surface water pH) were altered to investigate potential future outcomes. Our model simulations predict that although the Kaneohe Bay barrier reef will likely see a significant decline in NEC over the coming century, it is unlikely to reach a state of net erosion - a result contrary to several global coral reef model projections. In addition, we show that depending on the future response of NEP and NEC to OA and rising temperatures, the surface waters could switch from being a present-day source of CO2 to the atmosphere to a future sink. This ecosystem specific model can be applied to any reef system where data are available to constrain the initial model state and is a powerful tool for examining future changes in coral reef carbon budgets.

IMBER (Integrated Marine Biogeochemistry and Ecosystem Research: Support of Ocean Carbon Research

NASA Astrophysics Data System (ADS)

Rimetz-Planchon, J.; Gattuso, J.; Maddison, L.; Bakker, D. C.; Gruber, N.

2011-12-01

IMBER (Integrated Marine Biogeochemistry and Ecosystem Research), co-sponsored by SCOR (Scientific Committee on Oceanic Research) and IGBP (International Geosphere-Biosphere Programme), coordinates research that focuses on understanding and predicting changes in oceanic food webs and biogeochemical cycles that arise from global change. An integral part of this overall goal is to understand the marine carbon cycle, with emphasis on changes that may occur as a result of a changing climate, increased atmospheric CO2 levels and/or reduced oceanic pH. To address these key ocean carbon issues, IMBER and SOLAS (Surface Ocean Lower Atmosphere Study), formed the joint SOLAS-IMBER Carbon, or SIC Working Group. The SIC Working Group activities are organised into three sub-groups. Sub-group 1 (Surface Ocean Systems) focuses on synthesis, instrumentation and technology development, VOS (Voluntary Observing Ships) and mixed layer sampling strategies. The group contributed to the development of SOCAT (Surface Ocean CO2 Atlas, www.socat.info), a global compilation of underway surface water fCO2 (fugacity of CO2) data in common format. It includes 6.3 million measurements from 1767 cruises from 1968 and 2008 by more than 10 countries. SOCAT will be publically available and will serve a wide range of user communities. Its public release is planned for September 2011. SOCAT is strongly supported by IOCCP and CARBOOCEAN. Sub-group 2 (Interior Ocean Carbon Storage) covers inventory and observations, natural variability, transformation and interaction with modelling. It coordinated a review of vulnerabilities of the decadal variations of the interior ocean carbon and oxygen cycle. It has also developed a plan to add dissolved oxygen sensors to the ARGO float program in order to address the expected loss of oxygen as a result of ocean warming. The group also focuses on the global synthesis of ocean interior carbon observations to determine the oceanic uptake of anthropogenic CO2 since the mid 1990s. Sub-group 3 (SOLAS-IMBER Ocean Acidification or SIOA) coordinates international research efforts in ocean acidification and undertakes synthesis activities in ocean acidification at the international level. Several on-going synthesis activities, such as book projects and work by the Intergovernmental Panel on Climate Change (IPCC) are endorsed by this group. The SIOA developed a package of activities which it identified as critical to assess the effects of ocean acidification but are, for the most part, not funded at the national or regional levels and must be carried out at the international level. Among them is the promotion of international experiments, the sharing of experimental platforms, and the undertaking of inter-comparison exercises. The SIOA has submitted a proposal to launch an Ocean Acidification International Coordination Office in March 2011. This poster highlights some results from the SIC Working Group and indicates future challenges.

Impact of calcium and TOC on biological acidification assessment in Norwegian rivers.

PubMed

Schneider, Susanne C

2011-02-15

Acidification continues to be a major impact in freshwaters of northern Europe, and the biotic response to chemical recovery from acidification is often not a straightforward process. The focus on biological recovery is relevant within the context of the EU Water Framework Directive, where a biological monitoring system is needed that detects differences in fauna and flora compared to undisturbed reference conditions. In order to verify true reference sites for biological analyses, expected river pH is modeled based on Ca and TOC, and 94% of variability in pH at reference sites is explained by Ca alone, while 98% is explained by a combination of Ca and TOC. Based on 59 samples from 28 reference sites, compared to 547 samples from 285 non-reference sites, the impact of calcium and total organic carbon (TOC) on benthic algae species composition, expressed as acidification index periphyton (AIP), is analyzed. Rivers with a high Ca concentration have a naturally higher AIP, and TOC affects reference AIP only at low Ca concentrations. Four biological river types are needed for assessment of river acidification in Norway based on benthic algae: very calcium-poor, humic rivers (Ca<1 mg/l and TOC>2 mg/l); very calcium-poor, clear rivers (Ca<1 mg/l and TOC<2 mg/l); calcium-poor rivers (Ca between 1 and 4 mg/l); moderately calcium rich rivers (Ca>4 mg/l). A biological assessment system for river acidification in Norway based on benthic algae is presented, following the demands of the Water Framework Directive. Copyright © 2010 Elsevier B.V. All rights reserved.

Imminent onset and abrupt increase in duration of low aragonite and calcite saturation state events in the Southern Ocean

NASA Astrophysics Data System (ADS)

Friedrich, T.; Hauri, C.; Timmermann, A.

2015-12-01

Rapid progression of ocean acidification is a threat to key organisms of the Southern Ocean ecosystem. While the severity of ocean acidification impacts is mainly determined by the duration, intensity, and spatial extent of low aragonite or calcite saturation state events, little is known about the nature of these events, their evolving attributes, and the timing of their onset. Using output of historical and RCP 8.5 simulations from ten Earth System Models from CMIP5, we found that aragonite undersaturation, which decreases the calcification rate of pteropods and causes dissolution of their aragonitic shell, will spread rapidly after 2035, covering 70 % of the Southern Ocean surface waters by 2095. Surface aragonite undersaturation events will last for about 5 months in areas south of 60°S by 2055, and for more than 8 months by the end of the century. Overall, the duration of these events increases from 1 month to more than 6 months within fewer than 20 years in >75 % of the affected area. This abrupt change in exposure duration to unfavorable conditions may be too fast for pteropods to adapt, as these chemical changes will occur within just a few generations. As a result of two month-long calcite undersaturation events projected for the end of this century, even organisms built of the more stable calcium carbonate mineral calcite will face prolonged chemical dissolution. The threat of ocean acidification to the Southern Ocean ecosystem may be more imminent than previously thought, and may spread quickly to the southern tips of New Zealand, South America, and South Africa, with potentially far-reaching consequences to fisheries, local economies, and livelihoods.

Rapid releases of metal salts and nutrients following the deposition of volcanic ash into aqueous environments

NASA Astrophysics Data System (ADS)

Jones, Morgan T.; Gislason, Sigurður R.

2008-08-01

Deposition of volcanic ash into aqueous environments leads to dissolution of adsorbed metal salts and aerosols, increasing the bioavailability of key nutrients. Volcanogenic fertilization events could increase marine primary productivity, leading to a drawdown of atmospheric CO 2. Here we conduct flow-through experiments on unhydrated volcanic ash samples from a variety of locations and sources, measuring the concentrations and fluxes of elements into de-ionized water and two contrasting ocean surface waters. Comparisons of element fluxes show that dissolution of adsorbed surface salts and aerosols dominates over glass dissolution, even in sustained low pH conditions. These surface ash-leachates appear unstable, decaying in situ even if kept unhydrated. Volcanic ash from recent eruptions is shown to have a large fertilization potential in both fresh and saline water. Fluorine concentrations are integral to bulk dissolution rates and samples with high F concentrations display elevated fluxes of some nutrients, particularly Fe, Si, and P. Bio-limiting micronutrients are released in large quantities, suggesting that subsequent biological growth will be limited by macronutrient availability. Importantly, acidification of surface waters and high fluxes of toxic elements highlights the potential of volcanic ash-leachates to poison aqueous environments. In particular, large pH changes can cause undersaturation of CaCO 3 polymorphs, damaging populations of calcifying organisms. Deposition of volcanic ash can both fertilize and/or poison aqueous environments, causing significant changes to surface water chemistry and biogeochemical cycles.

Chemical and biological status of lakes and streams in the upper midwest: assessment of acidic deposition effects

USGS Publications Warehouse

Wiener, J.G.; Eilers, J.M.

1987-01-01

Many lakes in three areas in the Upper Midwest - northeastern Minnesota, northern Wisconsin, and the Upper Peninsula of Michigan - have low acid neutralizing capacity (ANC) and may be susceptible to change by acidic deposition. Northcentral Wisconsin and the Upper Peninsula of Michigan together contain about 150-300 acidic lakes (ANC ≤ 0), whereas none have been found in Minnesota. These acidic lakes are precipitation-dominated, Clearwater seepage lakes having small surface area, shallow depth, and low concentrations of dissolved organic carbon. The spatial distribution of these acidic lakes parallels a west to east gradient of increasing sulfate and hydrogen ion deposition. Several of these acidic lakes exhibit chemical characteristics and biological changes consistent with those observed elsewhere in waters reported to be acidified by acidic deposition. However, an hypothesis of recent lake acidification is not supported by analyses of either historical chemical data or diatom remains in lake sediments, and natural sources of acidity and alternative ecological processes have not been conclusively eliminated as causative factors. Streams in this three-state region have high ANC and appear to be insensitive to acidic deposition. The species richness and composition of lacustrine fish communities in the region are partly related to pH and associated chemical factors. Sport fishes considered acid-sensitive and of primary concern with regard to acidification include walleye, smallmouth bass, and black crappie. The fishery in at least one lake, Morgan Lake in Wisconsin (pH 4.6), may have declined because of acidification. Given the general lack of quantitative fishery data for acidic Wisconsin and Michigan lakes, however, more general conclusions concerning impacts or the absence of impacts of acidification on the region's fishery resources are not possible.

Hypoxia and Acidification Have Additive and Synergistic Negative Effects on the Growth, Survival, and Metamorphosis of Early Life Stage Bivalves

PubMed Central

Gobler, Christopher J.; DePasquale, Elizabeth L.; Griffith, Andrew W.; Baumann, Hannes

2014-01-01

Low oxygen zones in coastal and open ocean ecosystems have expanded in recent decades, a trend that will accelerate with climatic warming. There is growing recognition that low oxygen regions of the ocean are also acidified, a condition that will intensify with rising levels of atmospheric CO2. Presently, however, the concurrent effects of low oxygen and acidification on marine organisms are largely unknown, as most prior studies of marine hypoxia have not considered pH levels. We experimentally assessed the consequences of hypoxic and acidified water for early life stage bivalves (bay scallops, Argopecten irradians, and hard clams, Mercenaria mercenaria), marine organisms of significant economic and ecological value and sensitive to climate change. In larval scallops, experimental and naturally-occurring acidification (pH, total scale  = 7.4–7.6) reduced survivorship (by >50%), low oxygen (30–50 µM) inhibited growth and metamorphosis (by >50%), and the two stressors combined produced additively negative outcomes. In early life stage clams, however, hypoxic waters led to 30% higher mortality, while acidified waters significantly reduced growth (by 60%). Later stage clams were resistant to hypoxia or acidification separately but experienced significantly (40%) reduced growth rates when exposed to both conditions simultaneously. Collectively, these findings demonstrate that the consequences of low oxygen and acidification for early life stage bivalves, and likely other marine organisms, are more severe than would be predicted by either individual stressor and thus must be considered together when assessing how ocean animals respond to these conditions both today and under future climate change scenarios. PMID:24416169

Evaluating Carbonate System Algorithms in a Nearshore System: Does Total Alkalinity Matter?

PubMed Central

Sweet, Julia; Brzezinski, Mark A.; McNair, Heather M.; Passow, Uta

2016-01-01

Ocean acidification is a threat to many marine organisms, especially those that use calcium carbonate to form their shells and skeletons. The ability to accurately measure the carbonate system is the first step in characterizing the drivers behind this threat. Due to logistical realities, regular carbonate system sampling is not possible in many nearshore ocean habitats, particularly in remote, difficult-to-access locations. The ability to autonomously measure the carbonate system in situ relieves many of the logistical challenges; however, it is not always possible to measure the two required carbonate parameters autonomously. Observed relationships between sea surface salinity and total alkalinity can frequently provide a second carbonate parameter thus allowing for the calculation of the entire carbonate system. Here, we assessed the rigor of estimating total alkalinity from salinity at a depth <15 m by routinely sampling water from a pier in southern California for several carbonate system parameters. Carbonate system parameters based on measured values were compared with those based on estimated TA values. Total alkalinity was not predictable from salinity or from a combination of salinity and temperature at this site. However, dissolved inorganic carbon and the calcium carbonate saturation state of these nearshore surface waters could both be estimated within on average 5% of measured values using measured pH and salinity-derived or regionally averaged total alkalinity. Thus we find that the autonomous measurement of pH and salinity can be used to monitor trends in coastal changes in DIC and saturation state and be a useful method for high-frequency, long-term monitoring of ocean acidification. PMID:27893739

Evaluating Carbonate System Algorithms in a Nearshore System: Does Total Alkalinity Matter?

PubMed

Jones, Jonathan M; Sweet, Julia; Brzezinski, Mark A; McNair, Heather M; Passow, Uta

2016-01-01

Ocean acidification is a threat to many marine organisms, especially those that use calcium carbonate to form their shells and skeletons. The ability to accurately measure the carbonate system is the first step in characterizing the drivers behind this threat. Due to logistical realities, regular carbonate system sampling is not possible in many nearshore ocean habitats, particularly in remote, difficult-to-access locations. The ability to autonomously measure the carbonate system in situ relieves many of the logistical challenges; however, it is not always possible to measure the two required carbonate parameters autonomously. Observed relationships between sea surface salinity and total alkalinity can frequently provide a second carbonate parameter thus allowing for the calculation of the entire carbonate system. Here, we assessed the rigor of estimating total alkalinity from salinity at a depth <15 m by routinely sampling water from a pier in southern California for several carbonate system parameters. Carbonate system parameters based on measured values were compared with those based on estimated TA values. Total alkalinity was not predictable from salinity or from a combination of salinity and temperature at this site. However, dissolved inorganic carbon and the calcium carbonate saturation state of these nearshore surface waters could both be estimated within on average 5% of measured values using measured pH and salinity-derived or regionally averaged total alkalinity. Thus we find that the autonomous measurement of pH and salinity can be used to monitor trends in coastal changes in DIC and saturation state and be a useful method for high-frequency, long-term monitoring of ocean acidification.

Compensation of ocean acidification effects in Arctic phytoplankton assemblages

NASA Astrophysics Data System (ADS)

Hoppe, Clara Jule Marie; Wolf, Klara K. E.; Schuback, Nina; Tortell, Philippe D.; Rost, Björn

2018-06-01

The Arctic and subarctic shelf seas, which sustain large fisheries and contribute to global biogeochemical cycling, are particularly sensitive to ongoing ocean acidification (that is, decreasing seawater pH due to anthropogenic CO2 emissions). Yet, little information is available on the effects of ocean acidification on natural phytoplankton assemblages, which are the main primary producers in high-latitude waters. Here we show that coastal Arctic and subarctic primary production is largely insensitive to ocean acidification over a large range of light and temperature levels in different experimental designs. Out of ten CO2-manipulation treatments, significant ocean acidification effects on primary productivity were observed only once (at temperatures below 2 °C), and shifts in the species composition occurred only three times (without correlation to specific experimental conditions). These results imply a high capacity to compensate for environmental variability, which can be understood in light of the environmental history, tolerance ranges and intraspecific diversity of the dominant phytoplankton species.

Trends of pH decrease in the Mediterranean Sea through high frequency observational data: indication of ocean acidification in the basin

NASA Astrophysics Data System (ADS)

Flecha, Susana; Pérez, Fiz F.; García-Lafuente, Jesús; Sammartino, Simone; Ríos, Aida. F.; Huertas, I. Emma

2015-11-01

A significant fraction of anthropogenic carbon dioxide (CO2) released to the atmosphere is absorbed by the oceans, leading to a range of chemical changes and causing ocean acidification (OA). Assessing the impact of OA on marine ecosystems requires the accurate detection of the rate of seawater pH change. This work reports the results of nearly 3 years of continuous pH measurements in the Mediterranean Sea at the Strait of Gibraltar GIFT time series station. We document a remarkable decreasing annual trend of -0.0044 ± 0.00006 in the Mediterranean pH, which can be interpreted as an indicator of acidification in the basin based on high frequency records. Modeling pH data of the Mediterranean outflow allowed to discriminate between the pH values of its two main constituent water masses, the Levantine Intermediate Water (LIW) and the Western Mediterranean Deep Water (WMDW). Both water masses also exhibited a decline in pH with time, particularly the WMDW, which can be related to their different biogeochemical nature and processes occurring during transit time from formation sites to the Strait of Gibraltar.

Giant Clams and Rising CO2: Light May Ameliorate Effects of Ocean Acidification on a Solar-Powered Animal

PubMed Central

Watson, Sue-Ann

2015-01-01

Global climate change and ocean acidification pose a serious threat to marine life. Marine invertebrates are particularly susceptible to ocean acidification, especially highly calcareous taxa such as molluscs, echinoderms and corals. The largest of all bivalve molluscs, giant clams, are already threatened by a variety of local pressures, including overharvesting, and are in decline worldwide. Several giant clam species are listed as ‘Vulnerable’ on the IUCN Red List of Threatened Species and now climate change and ocean acidification pose an additional threat to their conservation. Unlike most other molluscs, giant clams are ‘solar-powered’ animals containing photosynthetic algal symbionts suggesting that light could influence the effects of ocean acidification on these vulnerable animals. In this study, juvenile fluted giant clams Tridacna squamosa were exposed to three levels of carbon dioxide (CO2) (control ~400, mid ~650 and high ~950 μatm) and light (photosynthetically active radiation 35, 65 and 304 μmol photons m-2 s-1). Elevated CO2 projected for the end of this century (~650 and ~950 μatm) reduced giant clam survival and growth at mid-light levels. However, effects of CO2 on survival were absent at high-light, with 100% survival across all CO2 levels. Effects of CO2 on growth of surviving clams were lessened, but not removed, at high-light levels. Shell growth and total animal mass gain were still reduced at high-CO2. This study demonstrates the potential for light to alleviate effects of ocean acidification on survival and growth in a threatened calcareous marine invertebrate. Managing water quality (e.g. turbidity and sedimentation) in coastal areas to maintain water clarity may help ameliorate some negative effects of ocean acidification on giant clams and potentially other solar-powered calcifiers, such as hard corals. PMID:26083404

Giant Clams and Rising CO2: Light May Ameliorate Effects of Ocean Acidification on a Solar-Powered Animal.

PubMed

Watson, Sue-Ann

2015-01-01

Global climate change and ocean acidification pose a serious threat to marine life. Marine invertebrates are particularly susceptible to ocean acidification, especially highly calcareous taxa such as molluscs, echinoderms and corals. The largest of all bivalve molluscs, giant clams, are already threatened by a variety of local pressures, including overharvesting, and are in decline worldwide. Several giant clam species are listed as 'Vulnerable' on the IUCN Red List of Threatened Species and now climate change and ocean acidification pose an additional threat to their conservation. Unlike most other molluscs, giant clams are 'solar-powered' animals containing photosynthetic algal symbionts suggesting that light could influence the effects of ocean acidification on these vulnerable animals. In this study, juvenile fluted giant clams Tridacna squamosa were exposed to three levels of carbon dioxide (CO2) (control ~400, mid ~650 and high ~950 μatm) and light (photosynthetically active radiation 35, 65 and 304 μmol photons m-2 s-1). Elevated CO2 projected for the end of this century (~650 and ~950 μatm) reduced giant clam survival and growth at mid-light levels. However, effects of CO2 on survival were absent at high-light, with 100% survival across all CO2 levels. Effects of CO2 on growth of surviving clams were lessened, but not removed, at high-light levels. Shell growth and total animal mass gain were still reduced at high-CO2. This study demonstrates the potential for light to alleviate effects of ocean acidification on survival and growth in a threatened calcareous marine invertebrate. Managing water quality (e.g. turbidity and sedimentation) in coastal areas to maintain water clarity may help ameliorate some negative effects of ocean acidification on giant clams and potentially other solar-powered calcifiers, such as hard corals.

Sea water acidification affects osmotic swelling, regulatory volume decrease and discharge in nematocytes of the jellyfish Pelagia noctiluca.

PubMed

Morabito, Rossana; Marino, Angela; Lauf, Peter K; Adragna, Norma C; La Spada, Giuseppa

2013-01-01

Increased acidification/PCO2 of sea water is a threat to the environment and affects the homeostasis of marine animals. In this study, the effect of sea water pH changes on the osmotic phase (OP), regulatory volume decrease (RVD) and discharge of the jellyfish Pelagia noctiluca (Cnidaria, Scyphozoa) nematocytes, collected from the Strait of Messina (Italy), was assessed. Isolated nematocytes, suspended in artificial sea water (ASW) with pH 7.65, 6.5 and 4.5, were exposed to hyposmotic ASW of the same pH values and their osmotic response and RVD measured optically in a special flow through chamber. Nematocyte discharge was analyzed in situ in ASW at all three pH values. At normal pH (7.65), nematocytes subjected to hyposmotic shock first expanded osmotically and then regulated their cell volume within 15 min. Exposure to hyposmotic ASW pH 6.5 and 4.5 compromised the OP and reduced or totally abrogated the ensuing RVD, respectively. Acidic pH also significantly reduced the nematocyte discharge response. Data indicate that the homeostasis and function of Cnidarians may be altered by environmental changes such as sea water acidification, thereby validating their use as novel bioindicators for the quality of the marine environment. © 2014 S. Karger AG, Basel.

Steady-state sulfur critical loads and exceedances for protection of aquatic ecosystems in the U.S. southern Appalachian Mountains

Treesearch

Todd C. McDonnell; Timothy J. Sullivan; Paul F. Hessburg; Keith M. Reynolds; Nicholas A. Povak; Bernard J. Cosby; William Jackson; R. Brion Salter

2014-01-01

Atmospherically deposited sulfur (S) causes stream water acidification throughout the eastern U.S. Southern Appalachian Mountain (SAM) region. Acidification has been linked with reduced fitness and richness of aquatic species and changes to benthic communities. Maintaining acid-base chemistry that supports native biota depends largely on balancing acidic deposition...

The inorganic carbon distribution in Irish coastal waters

NASA Astrophysics Data System (ADS)

McGrath, Triona; Cave, Rachel; McGovern, Evin; Kivimae, Caroline

2014-05-01

Despite their relatively small surface area, coastal and shelf waters play a crucial role in the global climate through their influence on major biogeochemical cycles. Due to growing concern about ocean acidification as a result of increasing atmospheric CO2 concentrations, measurements of inorganic carbon parameters (dissolved inorganic carbon (DIC), total alkalinity (TA), pH and pCO2) have been made with increasing regularity over the past two decades. While it is clear that open ocean surface waters are acidifying at a fairly uniform rate ( -0.02 pH units per decade), less is known about changes in coastal waters due to the high complexity and spatial variability in these regions. Large spatial and temporal variability in coastal CO2 parameters is mainly due to nutrient inputs, biological activity, upwelling and riverine inputs of alkalinity and inorganic and organic carbon. The inorganic carbon system in Irish coastal waters is presented here, gathered from 9 surveys around the Irish coastline between 2009 and 2013. There are striking contrasts in the CO2 system between different areas, largely attributed to the bedrock composition of the nearby rivers. Freshwater end-member concentrations of TA, calculated from TA-salinity relationships in outer estuarine and nearshore coastal water, were supported by riverine TA data from the Irish Environmental Protection Agency. A large portion of Ireland is covered with limestone bedrock and as a result, many of the rivers have extremely high TA (>5000μmol/kg) due to the carbonate mineral content of the underlying bedrock. While such high TA has resulted in elevated pH and calcium carbonate saturation states in some coastal waters, (e.g. Galway Bay and Dublin Bay), the high TA in other areas was accompanied by particularly high DIC (e.g. River Shannon on the west coast), resulting in lower pH and aragonite/calcite saturation states and even CO2 degassing in the Shannon estuary. Due to non-limestone lithology in many parts of Northern Ireland, rivers and surrounding coastal water have lower TA and hence calcium carbonate saturation states that are directly related to salinity (e.g. Lough Foyle). This study highlights the complexity of the inorganic carbon system in Irish waters and the need for region-specific case studies to be carried out to assess the potential impacts of ocean acidification on coastal ecosystems.

Behavioral Response of Hermit Crabs (Clibanarius digueti) to Dissolved Carbon Dioxide

NASA Astrophysics Data System (ADS)

Maier, H. J.

2015-12-01

CO2 induced ocean acidification is currently changing the population dynamics of marine organisms. As a result of ocean acidification, marine organisms expend extra energy on modifying behaviors. The current rate of ocean acidification will deplete the marine food chain that much of the world relies on as their major food supply. The purpose of this study was to understand whether and how ocean acidification affects the behavior of hermit crabs Clibanarius digueti. We hypothesized that an increase in carbonic acid would modify grazing and individual movement, because an increase in acidification alters the normal chemical composition of the water and potentially the niche occupancy of C. digueti. A model tidal pool experiment consisting of two tanks (control and treatment) inhabited with seven living C. digueti was set up in the Ocean Biome of Biosphere-2. Each tank was also provided with uninhabited shells: two Turbo fluctuosa and four Cerithium sp. Gaseous CO2 was dissolved into a treatment tank and measured as dissolved CO2 by using a sodium hydroxide titration method. Additionally, water conditions were characterized for UV- light and temperature. Two trials were run in this experiment with tanks and treatments interchanged in each trial. We assessed whether increased CO2 affected hermit crab shell change rate. We found that shell changes only happened among C. digueti placed under increased CO2. The information from this analysis will allow us to assess whether ocean acidification affects basic behavior in hermit crabs, which could later affect population dynamics. Bringing together all of this information will allow us to measure the effects of climate change on the behavior of C.Digueti.

Acid-induced changes in DOC quality in an experimental whole-lake manipulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Donahue, W.F.; Schindler, D.W.; Page, S.J.

1998-10-01

Fluorescence analyses of archived water samples were used to typify dissolved organic carbon (DOC) quality in experimentally acidified lakes and reference lakes at the Experimental Lakes Area, in northwestern Ontario. Carbon-specific DOC fluorescence (CSF) during peak acidification was 40--50% of that for a high-DOC reference lake and similar to a low-DOC reference lake. Reference lakes showed similar but smaller decreases in CSF during several years of prolonged drought in the late 1980s. During the 1990s, recovery from acidification resulted in increased CSF, whereas reference lakes remained unchanged during the same time period. In addition to causing decreased [DOC], acidification causesmore » changes in fluorescence-peak geometry that indicate a switch in DOC quality from allochthonous to autochthonous-like during acidification. The acid-induced change in DOC quality was likely due to increased chemical oxidation or precipitation of the UV-absorbent aromatic portions of allochthonous DOC molecules, leaving more UV-transparent aliphatic chains. The change in the nature of DOC following acidification and drought may have an important role in physical, biological, and chemical processes within these lakes. With recovery from acidification, DOC quality has also recovered.« less

Metal concentrations in aquatic macrophytes as influenced by soil and acidification

USGS Publications Warehouse

Sparling, D.W.; Lowe, T.P.

1998-01-01

Bioavailability of metals to aquatic plants is dependent on many factors including ambient metal concentration, pH of soil or water, concentration of ligands, competition with other metals for binding sites, and mode of exposure. Plants may be exposed to metals through water, air, or soil, depending on growth form. This paper examines the influence of soil type under two regimens of water acidification on metal uptake by four species of aquatic macrophytes: smartweed (Polygonum sagittatum), burreed (Sparganium americanum), pondweed (Potamogeton diversifolius), and bladderwort (Utricularia vulgaris) in constructed, experimentally acidified wetlands. Soil types consisted of a comparatively high-metal clay or a lower-metal sandy loam. Each pond was either acidified to pH ca. 4.85.3 or allowed to remain circumneutral. Metal concentrations tended to be higher in the submerged bladderwort and pondweed than in the emergent burreed and smartweed. Soils were important to plant metal concentrations in all species, but especially in the emergents. Acidification influenced plant concentrations of some metals and was especially important in the submerged pondweed. Bioaccumulation of metals occurred for Mn, B, Sr, Ba, and Zn, compared to soil concentrations.

Environmental impact assessment of leachate recirculation in landfill of municipal solid waste by comparing with evaporation and discharge (EASEWASTE).

PubMed

Xing, Wei; Lu, Wenjing; Zhao, Yan; Zhang, Xu; Deng, Wenjing; Christensen, Thomas H

2013-02-01

In some arid regions where landfill produces minimal amount of leachate, leachate recirculation is suggested as a cost-effective option. However, its long-term impacts to environment remain disputed. For the purpose of revealing the environmental impacts of leachate recirculation in landfill, four scenarios were modeled using EASEWASTE, comparing the strategies of leachate recirculation (with or without gas management), evaporation and discharge. In the current situation (Scenario A), a total of 280 t of waste was generated and then transported to a conventional landfill for disposal. A number of contaminants derived from waste can be stored in the landfill for long periods, with 11.69 person equivalent (PE) for stored ecotoxicity in water and 29.62 PE for stored ecotoxicity in soil, considered as potential risks of releasing to the environment someday. Meanwhile, impacts to ecotoxicity and human toxicity in surface water, and those to groundwater, present relatively low levels. In Scenario B, leachate evaporation in a collecting pool has minimal impacts on surface water. However, this strategy significantly impacts groundwater (1055.16 PE) because of the potential infiltration of leachate, with major contaminants of As, ammonia, and Cd. A number of ions, such as Cl(-), Mg(2+), and Ca(2+), may also contaminate groundwater. In Scenario C, the direct discharge of leachate to surface water may result in acidification (2.71 PE) and nutrient enrichment (2.88 PE), primarily attributed to soluble ammonia in leachate and the depositional ammonia from biogas. Moreover, the direct discharge of leachate may also result in ecotoxicity and human toxicity via water contaminated by heavy metals in leachate, with 3.96 PE and 11.64 PE respectively. The results also show that landfill gas is the main contributor to global warming and photochemical ozone formation due to methane emission. In Scenario D, landfill gas flaring was thus be modeled and proven to be efficient for reducing impacts by approximately 90% in most categories, like global warming, photochemical ozone formation, acidification, nutrient enrichment, ecotoxicity, and human toxicity. Therefore, leachate recirculation is considered a cost-effective and environmentally viable solution for the current situation, and landfill gas treatment is urgently required. These results can provide important evidence for leachate and gas management of landfill in arid regions. Copyright © 2012 Elsevier Ltd. All rights reserved.

Aragonite saturation states and nutrient fluxes in coral reef sediments in Biscayne National Park, FL, USA

USGS Publications Warehouse

Lisle, John T.; Reich, Christopher D.; Halley, Robert B.

2014-01-01

Some coral reefs, such as patch reefs along the Florida Keys reef tract, are not showing significant reductions in calcification rates in response to ocean acidification. It has been hypothesized that this recalcitrance is due to local buffering effects from biogeochemical processes driven by seagrasses. We investigated the influence that pore water nutrients, dissolved inorganic carbon (DIC) and total alkalinity (TA) have on aragonite saturation states (Ωaragonite) in the sediments and waters overlying the sediment surfaces of sand halos and seagrass beds that encircle Alinas and Anniversary reefs in Biscayne National Park. Throughout the sampling period, sediment pore waters from both bottom types had lower oxidation/reduction potentials (ORP), with lower pH relative to the sediment surface waters. The majority (86.5%) of flux rates (n = 96) for ΣNOx–, PO43–, NH4+, SiO2, DIC and TA were positive, sometimes contributing significant concentrations of the respective constituents to the sediment surface waters. The Ωaragonite values in the pore waters (range: 0.18 to 4.78) were always lower than those in the overlying waters (2.40 to 4.46), and 52% (n = 48) of the values were aragonite in 75% (n = 16) of the samples, but increased it in the remainder. The elevated fluxes of nutrients, DIC and TA into the sediment–water interface layer negatively alters the suitability of this zone for the settlement and development of calcifying larvae, while enhancing the establishment of algal communities.

Resilience of SAR11 bacteria to rapid acidification in the high-latitude open ocean.

PubMed

Hartmann, Manuela; Hill, Polly G; Tynan, Eithne; Achterberg, Eric P; Leakey, Raymond J G; Zubkov, Mikhail V

2016-02-01

Ubiquitous SAR11 Alphaproteobacteria numerically dominate marine planktonic communities. Because they are excruciatingly difficult to cultivate, there is comparatively little known about their physiology and metabolic responses to long- and short-term environmental changes. As surface oceans take up anthropogenic, atmospheric CO2, the consequential process of ocean acidification could affect the global biogeochemical significance of SAR11. Shipping accidents or inadvertent release of chemicals from industrial plants can have strong short-term local effects on oceanic SAR11. This study investigated the effect of 2.5-fold acidification of seawater on the metabolism of SAR11 and other heterotrophic bacterioplankton along a natural temperature gradient crossing the North Atlantic Ocean, Norwegian and Greenland Seas. Uptake rates of the amino acid leucine by SAR11 cells as well as other bacterioplankton remained similar to controls despite an instant ∼50% increase in leucine bioavailability upon acidification. This high physiological resilience to acidification even without acclimation, suggests that open ocean dominant bacterioplankton are able to cope even with sudden and therefore more likely with long-term acidification effects. © FEMS 2015. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

The big squeeze: ecosystem change and contraction of habitat for newly discovered deep-water reefs off the U.S. West Coast

NASA Astrophysics Data System (ADS)

Wickes, L.; Etnoyer, P. J.; Lauermann, A.; Rosen, D.

2016-02-01

Cold-water reefs are fragile, complex ecosystems that extend into the bathyal depths of the ocean, creating three dimensional structure and habitat for a diversity of deep-water invertebrates and fishes. The cold waters of the California Current support a diverse assemblage of these corals at relatively shallow depths close to shore. At these depths and locations the communities face a multitude of stressors, including low carbonate saturations, hypoxia, changing temperature, and coastal pollution. The current study employed ROV surveys (n=588, 2003-2015) to document the distribution of deep-sea corals in the Southern California Bight, including the first description of a widespread reef-building coral in the naturally acidified waters off the U.S. West Coast. We provide empirical evidence of species survival in the corrosive waters (Ωarag 0.67-1.86), but find loss of reef integrity. Recent publications have implied acclimation, resistance, and resilience of cold-water reef-building corals to ocean acidification, but results of this study indicate a cost to skeletal framework development with a subsequent loss of coral habitat. While ocean acidification and declines in oxygen are expected to further impinge on Lophelia at depth (𝑥̅=190 m), surface warming and coastal polution may affect shallower populations and mesophotic reef assemblages, resulting in a contraction of available coral habitat. Recent observations of die offs of gorgonians and antipatharians from surveys in shallow (50 m) and deep water (500 m) provide compelling evidence of ongoing ecosystem changes. Concurrent losses in habitat quality in deep and mesophotic waters suggest that corals may be "squeezed" into a more restricted depth range. New monitoring efforts aim to characterize the health and condition of deep corals with respect to gradients in carbonate chemistry, coastal pollution and changing temperatures, to assess vulnerability and both current and future habitat suitability.

Linkages Between Upwelling and Shell Characteristics of Mytilus californianus: Morphology and Stable Isotope (δ13C, δ18O) Signatures of a Carbonate Archive from the California Current

NASA Astrophysics Data System (ADS)

Hosfelt, J. D.; Hill, T. M.; Russell, A. D.; Bean, J. R.; Sanford, E.; Gaylord, B.

2014-12-01

Many calcareous organisms are known to record the ambient environmental conditions in which they grow, and their calcium carbonate skeletons are often valuable archives of climate records. Mytilus californianus, a widely distributed species of intertidal mussel, experiences a spatial mosaic of oceanographic conditions as it grows within the California Current System. Periodic episodes of upwelling bring high-CO2 waters to the surface, during which California coastal waters are similar to projected conditions and act as a natural analogue to future ocean acidification. To examine the link between upwelling and shell characteristics of M. californianus, we analyzed the morphology and stable isotope (δ13C, δ18O) signatures of mussel specimens collected live from seven study sites within the California Current System. Morphometric analyses utilized a combination of elliptic Fourier analysis and shell thickness measurements to determine the influence of low pH waters on the growth morphology and ecological fitness of M. californianus. These geochemical and morphological analyses were compared with concurrent high-resolution environmental (T, S, pH, TA, DIC) records from these seven study sites from 2010-2013. With appropriate calibration, new archives from modern M. californianus shells could provide a valuable tool to enable environmental reconstructions within the California Current System. These archives could in turn be used to predict the future consequences of continuing ocean acidification, as well as reconstruct past (archeological) conditions.

Groundwater protection: what can we learn from Germany?

PubMed

Zhu, Yan; Balke, Klaus-Dieter

2008-03-01

For drinking water security the German waterworks proceed on a comprehensive concept, i.e., the protection of all the regions from the recharge area to the client. It includes the protection of the recharge area by a precautionary management, a safe water treatment, a strict maintenance of the water distribution network, continuous control and an intensive training of staff. Groundwater protection zones together with effective regulations and control play a very important role. Three protection zones with different restrictions in land-use are distinguished. Water in reservoirs and lakes is also protected by Surface Water Protection Zones. Within the surrounding area the land-use is controlled, too. Special treatment is necessary if acidification happens caused by acid rain, or eutrophication caused by the inflow of sewage. Very important is the collaboration between waterworks and the farmers cultivating land in the recharge area in order to execute water-protecting ecological farming with the aim to reduce the application of fertilizers and plant protection agents. Probable financial losses have to be compensated by the waterworks.

The volcanic acidification of glacial Lake Caviahue, Province of Neuquen, Argentina

NASA Astrophysics Data System (ADS)

Varekamp, Johan C.

2008-12-01

Lake Caviahue (northern Patagonia, Argentina) is a large glacial lake acidified by volcanic fluids from Copahue volcano. The lake and the feeding rivers were sampled annually from 1997 till early 2006, including the eruptive period of 2000. Lake Caviahue waters evolved over time, with the most concentrated waters in 2000 during the eruptive period, followed by gradual dilution that was interrupted by renewed acidification in 2003-2004. Inversion of the lake water data and application of a dynamic non-steady state model for the lake provides our best quantitative estimates for the variation in element fluxes over the 9-year period. The model flux results agree well with most of the measured fluxes. The Copahue hydrothermal system had gently declining element fluxes between 1997 and mid-1999, although the lake was still becoming more concentrated. About 2-3 months before the 2000 eruption, element fluxes increased strongly, but the hydrothermal fluxes almost shutoff directly after the main eruptive events. The fluxes of several elements recovered post-2001, with an increase in element fluxes in 2003-2004; the lake became more dilute between 2004 and 2006. The intrusion of new magma into the hydrothermal system just prior to the 2000 eruption led to enhanced water rock interaction, with higher concentrations of the rock forming elements in the fluids, and the hot spring flow rate increased as a result of the higher pressure in the reservoir. The fluids became saturated in alunite and jarosite, and they were already saturated with anhydrite. Precipitation of these minerals possibly led to a decreased permeability of the hydrothermal reservoir, leading to the strongly reduced element fluxes just after the eruption. In addition, K, Al and S were retained in the newly precipitated minerals as well, further diminishing their export. The acidification in 2003-2004 may have resulted from a new small intrusion of magma or resulted from seismic activity that created new permeability and fresh rock surfaces for water rock interaction. The volcano is a significant source of toxic trace elements such as F, As, B and Li as well as a nutrient (P) for the local watershed. Monitoring of the hydrothermal fluids in the river that drains Copahue, especially the S/Cl, Mg/Cl and Mg/K values as well as the magnitude of the element fluxes would provide the best information for eruption forecasting for this volcano.

Environmental monitoring of Space Shuttle launches at Kennedy Space Center - The first ten years

NASA Technical Reports Server (NTRS)

Schmalzer, Paul A.; Hall, Carlton R.; Hinkle, C. R.; Duncan, Brean W.; Knott, William M., III; Summerfield, Burton R.

1993-01-01

Space Shuttle launches produce local environmental effects through the generation of a launcher exhaust plume that in turn produces acidic depositions and acute vegetation damage in the near-field environment; fish kills have also been noted in the lagoon or impoundment near each of the launch pads. Repeated launches lead to cumulative changes in plant community composition and structure, and temporary decreases in pH due to acidification increases metal availability in soil microcosms and surface waters. Direct effects on terrestrial fauna include the mortality of birds, mammals, amphibians, and reptiles in the near-field area.

Dialogue on Climate, Water, Energy and Human Security in Africa

DTIC Science & Technology

2014-07-01

winter periods.  The influence of the  ocean  mass on the coastal areas can be seen, with slightly lower increases in  average temperatures.       Figure 1...adaptation 1 1’ ~ + -foradaptllion m \\...A..AJ to reduce risk .... :’\\: " -••• \\ Warming Extreme Extreme Damaging Ocean Sea surface I Precipitation Sea...level Risk level with Risk level with trend temperature precipitation cyclone acidification temperature high adaptation cuJTentadaptation Institutions

Climate Change, National Security, and the Quadrennial Defense Review. Avoiding the Perfect Storm

DTIC Science & Technology

2008-01-01

consequently, higher ocean water temperatures are increasing the occurrence of coral bleaching and coral reef die-offs.57 The IPCC concludes that...unprecedented combination of climate change, associated disturbances (e.g., flooding, drought, wildfire, in- sects, ocean acidification ), and other global...instance, the disintegration of saltwater fishing indus- tries due to ocean acidification could spark inter- and intrastate conflict as numerous

Development of Ocean Acidification Flow-Thru Experimental Raceway Units (OAFTERU): Simulating the Future Reefs in the Keys Today

NASA Astrophysics Data System (ADS)

Hall, E. R.; Vaughan, D.; Crosby, M. P.

2011-12-01

Ocean acidification, a consequence of anthropogenic CO2 production due to fossil fuel combustion, deforestation, and cement production, has been referred to as "the other CO2 problem" and is receiving much attention in marine science and public policy communities. Critical needs that have been identified by top climate change and marine scientists include using projected pCO2 (partial pressure of CO2 in seawater) levels in manipulative experiments to determine physiological indices of ecologically important species, such as corals. Coral reefs were one of the first ecosystems to be documented as susceptible to ocean acidification. The Florida Keys reef system has already experienced a long-term deterioration, resulting in increased calls for large scale coral reef ecosystem restoration of these critical resources. It has also been speculated that this decline in reef ecosystem health may be exacerbated by increasing atmospheric CO2 levels with resulting ocean acidification. Therefore, reef resilience to ocean acidification and the potential for successful restoration of these systems under forecasted long-term modified pH conditions in the Florida Keys is of great concern. Many studies for testing effects of ocean acidification on corals have already been established and tested. However, many employ pH modification experimental designs that include addition of acid to seawater which may not mimic conditions of climate change induced ocean acidification. It would be beneficial to develop and maintain an ocean acidification testing system more representative of climate change induced changes, and specific to organisms and ecosystems indigenous to the Florida Keys reef tract. The Mote Marine Laboratory research facility in Summerland Key, FL has an established deep well from which its supply of seawater is obtained. This unique source of seawater is 80 feet deep, "fossil" marine water. It is pumped from the on-site aquifer aerated to reduce H2S and ammonia, and passed through filters for biofiltration, and clarification. The resulting water has a pH that is relatively acidic (pH around 7.6, pCO2 ranging from 200 to 2000 μatm). However, further aeration will adjust the pH of the water, by driving off more CO2, yielding pH levels at varying levels between 7.6 and present day values (>8.0-8.4). We are currently testing methods for utilizing this unique seawater system as the foundation for manipulative ocean acidification studies with Florida Keys corals and other reef ecosystem species in both flow-through and large mesocosm-based designs. Advance knowledge of potential climate-driven trends in coral growth and health will permit improved modeling for prediction and more effectively guide policy decisions for how financial resources should be directed to protection and restoration of coral reef ecosystems. Developing such longterm research infrastructure at the existing Mote Marine Laboratory Summerland Key facility will provide an optimum global research center for examining and modeling effects of ocean acidification on corals as well as other important estuarine and marine species.

Low pH Springs - A Natural Laboratory for Ocean Acidification

NASA Astrophysics Data System (ADS)

Derse, E.; Rebolledo-Vieyra, M.; Potts, D. C.; Paytan, A.

2009-12-01

Recent increases in atmospheric carbon dioxide of 40% above pre-industrial levels has resulted in rising aqueous CO2 concentrations that lower the pH of the oceans. Currently, the surface ocean has an average pH between 8.1 and 8.2: it is estimated that over the next 100 years this value will decrease by ~0.4 pH units. Previous studies have highlighted the negative impacts that changes in pH (and the resulting CaCO3 saturation state) have on marine organisms; however, to date, very little is known about the long-term impacts of ocean acidification on ecosystems as a whole. The Yucatán Peninsula of Quintana Roo, Mexico, represents an ecosystem where naturally low pH groundwater (7.25-8.07) has been discharging offshore at highly localized points (called ojos) since the last deglaciation. We present preliminary chemical and biological data on a selection of ojos from lagoon sites in Puerto Morelos, Mexico. We address the potential long-term implications of low pH waters on marine ecosystems.

Simulating carbon capture by enhanced weathering with croplands: an overview of key processes highlighting areas of future model development

PubMed Central

Quegan, Shaun; Banwart, Steven A.

2017-01-01

Enhanced weathering (EW) aims to amplify a natural sink for CO2 by incorporating powdered silicate rock with high reactive surface area into agricultural soils. The goal is to achieve rapid dissolution of minerals and release of alkalinity with accompanying dissolution of CO2 into soils and drainage waters. EW could counteract phosphorus limitation and greenhouse gas (GHG) emissions in tropical soils, and soil acidification, a common agricultural problem studied with numerical process models over several decades. Here, we review the processes leading to soil acidification in croplands and how the soil weathering CO2 sink is represented in models. Mathematical models capturing the dominant processes and human interventions governing cropland soil chemistry and GHG emissions neglect weathering, while most weathering models neglect agricultural processes. We discuss current approaches to modelling EW and highlight several classes of model having the potential to simulate EW in croplands. Finally, we argue for further integration of process knowledge in mathematical models to capture feedbacks affecting both longer-term CO2 consumption and crop growth and yields. PMID:28381633

Ocean acidification: One potential driver of phosphorus eutrophication.

PubMed

Ge, Changzi; Chai, Yanchao; Wang, Haiqing; Kan, Manman

2017-02-15

Harmful algal blooms which may be limited by phosphorus outbreak increases currently and ocean acidification worsens presently, which implies that ocean acidification might lead to phosphorus eutrophication. To verify the hypothesis, oxic sediments were exposed to seawater with different pH 30days. If pH was 8.1 and 7.7, the total phosphorus (TP) content in sediments was 1.52±0.50 and 1.29±0.40mg/g. The inorganic phosphorus (IP) content in sediments exposed to seawater with pH8.1 and 7.7 was 1.39±0.10 and 1.06±0.20mg/g, respectively. The exchangeable phosphorus (Ex-P) content in sediments was 4.40±0.45 and 2.82±0.15μg/g, if seawater pH was 8.1 and 7.7. Ex-P and IP contents in oxic sediments were reduced by ocean acidification significantly (p<5%). The reduced phosphorus in sediments diffused into water, which implied that ocean acidification was one potential facilitator of phosphorus eutrophication in oxic conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Hydrologic and geochemical factors affecting the chemistry of small headwater streams in response to acidic deposition on Catoctin Mountain, north-central Maryland

USGS Publications Warehouse

Rice, Karen C.; Bricker, Owen P.

1996-01-01

Hydrologic and water-quality data were collected at a precipitation-collection station and from two small watersheds on Catoctin Mountain, north- central Maryland, as part of an investigation of episodic acidification and its effects on streamwater quality. Data were collected from June 1990 through December 1993. Descriptions of the water shed instrumentation, data-collection techniques, and laboratory methods used to conduct the studies are included. Data that were collected on precipitation, throughfall, soil water, ground water, and streamwater during base flow and stormflow indicate that the streams undergo episodic acidification during storms. Both streams showed decreases in pH to less than 5.0 standard units during stormflow. The acid-neutralizing capacity (ANC) of both streams decreased during stormflow, and the ANC of one of the streams, Bear Branch, became negative. The chemistries of the different types of waters that were sampled indicate that shallow subsurface water with minimal residence time in the watersheds is routed to the streams to become stormflow and is the cause of the episodic acidification observed. Three-component hydrograph separations were performed on the data collected during several storms in each watershed. The hydrograph separations of all of the storms indicate that throughfall contributed 0 to 50 percent of the stormflow, soil water contributed 0 to 80 percent, and ground water contributed 20 to 90 percent. The results of the hydrograph separations indicate that, in general, the watershed with higher hydraulic gradients tends to have shallower and shorter flow paths than the watershed with lower hydraulic gradients.

Revisiting Mn and Fe removal in humic rich estuaries

NASA Astrophysics Data System (ADS)

Oldham, Véronique E.; Miller, Megan T.; Jensen, Laramie T.; Luther, George W.

2017-07-01

Metal removal by estuarine mixing has been studied for several decades, but few studies emphasize dissolved metal speciation and organic ligand complexation. Findings from the last decade indicate that metal-humic complexation can be significant for dissolved metals including Cu(II), Al(III) and Fe(III), but little consideration is given to the precipitation of these complexes with humic material at pH < 2. Given that total soluble metal analysis involves an acidification step for sample preservation, we show that Mn and other metal concentrations may have been underestimated in estuaries, especially when humic substance concentrations are high. A competitive ligand assay of selected samples from our study site, a coastal waterway bordered by wetlands (Broadkill River, DE), showed that Mn(III)-humic complexation is significant, and that some Mn(III)-L complexes precipitate during acidification. In the oxygenated surface waters of the Broadkill River, total dissolved Mn (dMnT) was up to 100% complexed to ambient ligands as Mn(III)-L, and we present evidence for humic-type Mn(III)-L complexes. The Mn(III) complexes were kinetically stabilized against Fe(II) reduction, even when [Fe(II)] was 17 times higher than [dMnT]. Unlike typical oceanic surface waters, [Fe(II)] > [Fe(III)-L] in surface waters, which may be attributed to high rates of photoreduction of Fe(III)-L complexes. Total [Mn(III)-L] ranged from 0.22 to 8.4 μM, in excess of solid MnOx (below 0.28 μM in all samples). Filtration of samples through 0.02 μm filters indicated that all Mn(III)-L complexes pass through the filters and were not colloidal species in contrast to dissolved Fe. Incubation experiments indicated that the reductive dissolution of solid MnOx by ambient ligands may be responsible for Mn(III) formation in this system. Unlike previous studies of estuarine mixing, which demonstrated metal removal during mixing, we show significant export of dMn and dissolved Fe (dFe) in the summer and fall of 2015. Thus, we propose that estuarine removal should be considered seasonal for dMn and dFe, with export in the summer and fall and removal during the winter.

Connecting the surface to near-shore bottom waters in the California Current ecosystem: a study of Northern California interannual to decadal oceanographic variability

NASA Astrophysics Data System (ADS)

Fish, C.; Hill, T. M.; Davis, C. V.; Lipski, D.; Jahncke, J.

2017-12-01

Elucidating both surface and bottom water ecosystem impacts of temperature change, acidification, and food web disruption are needed to understand anthropogenic processes in the ocean. The Applied California Current Ecosystem Studies (ACCESS) partnership surveys the California Current within the Greater Farallones and Cordell Bank National Marine Sanctuaries three times annually, sampling water column hydrography and discrete water samples from 0 m and 200 m depth at five stations along three primary transects. The transects span the continental shelf with stations as close as 13 km from the coastline to 65 km. This time series extends from 2004 to 2017, integrating information on climate, productivity, zooplankton abundance, oxygenation, and carbonate chemistry. We focus on the interpretation of the 2012-2017 carbonate chemistry data and present both long term trends over the duration of the time series as well as shorter term variability (e.g., ENSO, `warm blob' conditions) to investigate the region's changing oceanographic conditions. For example, we document oscillations in carbonate chemistry, oxygenation, and foraminiferal abundance in concert with interannual oceanographic variability and seasonal (upwelling) cycles. We concentrate on results from near Cordell Bank that potentially impact deep sea coral ecosystems.

Baseflow and peakflow chemical responses to experimental applications of ammonium sulphate to forested watersheds in north-central West Virginia, USA

Treesearch

Pamela J. Edwards; Frederica Wood; James N. Kochenderfer

2002-01-01

Stream water was analysed to determine how induced watershed acidification changed the chemistry of peakflow and baseflow and to compare the relative timing of these changes. Two watersheds in north-central West Virginia, WS3 and WS9, were subjected to three applications of ammonium sulphate fertilizer per year to induce acidification. A third watershed, WS4, was the...

Stream salamander species richness and abundance in relation to environmental factors in Shenandoah National Park, Virginia

USGS Publications Warehouse

Campbell Grant, Evan H.; Jung, Robin E.; Rice, Karen C.

2005-01-01

Stream salamanders are sensitive to acid mine drainage and may be sensitive to acidification and low acid neutralizing capacity (ANC) of a watershed. Streams in Shenandoah National Park, Virginia, are subject to episodic acidification from precipitation events. We surveyed 25 m by 2 m transects located on the stream bank adjacent to the water channel in Shenandoah National Park for salamanders using a stratified random sampling design based on elevation, aspect and bedrock geology. We investigated the relationships of four species (Eurycea bislineata, Desmognathus fuscus, D. monticola and Gyrinophilus porphyriticus) to habitat and water quality variables. We did not find overwhelming evidence that stream salamanders are affected by the acid-base status of streams in Shenandoah National Park. Desmognathus fuscus and D. monticola abundance was greater both in streams that had a higher potential to neutralize acidification, and in higher elevation (>700 m) streams. Neither abundance of E. bislineata nor species richness were related to any of the habitat variables. Our sampling method preferentially detected the adult age class of the study species and did not allow us to estimate population sizes. We suggest that continued monitoring of stream salamander populations in SNP will determine the effects of stream acidification on these taxa.

Assessment of acidification and eutrophication in the coastal waters of Bolinao, Pangasinan, Philippines

NASA Astrophysics Data System (ADS)

Lagumen, M. C. T.; San Diego-McGlone, M. L.

2014-12-01

Ocean acidification is becoming a global concern due to its potential effects on marine resources. In coastal areas, an emerging problem is ocean acidicification due to eutrophication resulting from human activities. The coastal water of Bolinao, Pangasinan, Philippines has become eutrophic due to increased nutrient loading from unconsumed fish feeds in fish cages. Mariculture is a big industry in Bolinao. In over a decade, the area has experienced decreased oxygen levels leading to hypoxia, fish kills, and algal blooms. The decomposition of organic matter from unconsumed fish feeds results not only to high nutrient buildup but also increased CO2 and acidity in the area. Nutrients (ammonia, nitrate, nitrite, phosphate and silicate), total alkalinity (TA), dissolved inorganic carbon (DIC), pH, dissolved oxygen (DO), aragonite saturation state (Ωarg) and partial pressure of carbon dioxide (pCO2) were measured to determine the combined effect of acidification and eutrophication in Bolinao. Monitoring results have shown an increase in nutrients by 30% to 70% in over a decade. Stratified water during rainy season have resulted in low DO (<5.5) and acidic water (<7.5) with high pCO2 level (>900 μatm). Shallow stations with poor water circulation have shown undersaturated aragonite state (< 2.0) and high pCO2 levels of 800 matm. The eutrophic and acidified coastal waters of Bolinao are already affecting the seagrass and coral reef ecosystems in the area.

Real-Time monitoring of the eutrophication and hypoxia off the Changjiang Estuary

NASA Astrophysics Data System (ADS)

Chen, J. F.

2016-02-01

Inputs of anthropogenic nutrients and carbon dioxide-rich waters to the coastal waters can not only lead to eutrophication in the surface water and hypoxia in the bottom water, but also will enhance acidification of coastal water. In order to understand the details mechanism of concurrence of eutrophication and hypoxia in the Changjiang Estuary, a real time monitoring system has been established since 2010 under the support of Chinese National Key Technologies R&D Program and Chinese Marine Research Special Funds for Public Welfare Projects. The platforms of the monitoring system includes a 3-meter buoy with water column chain unit and a seabed mounted unit, the sensors includes those can detect wind speed and direction, air and water temperature, salinity, currents, PAR, DO, pH, nutrients, Chl a, turbidity and pCO2 etc.. Two highlights of our scientific findings will introduced in this presentation, one is how typhoon affected the coastal hypoxia (positive and negative), and the other is how fresh water input induced a algal bloom in the Changjiang Estuary in summer.

The Phenomenom of Ocean Acidification

NASA Astrophysics Data System (ADS)

Weiss, S.

2017-12-01

The earth is 70% and is protected by its atmosphere. The atmosphere is made up of several layers. The sunlight penetrates through the atmosphere and warms the earth surface. The earth's surface then in turn emits invisible infrared radiation back. As this radiation moves back up each layer absorbs some of it. Each layer then sends some of this energy back to earth again. When the layer becomes so thin the energy then escapes back into space. When we are adding more carbon dioxide to these layers we are causing the layers to absorb more of the energy and the radiation. This in turn causes the layers to become warmer since fewer radiation moves up through the layers and this energy bounces back to earth increasing the temperatures. The entire planet is taking on more of this energy and hence the temperatures are rising. The ocean plays a big rule in this change. It has prevented some of the CO2 from entering the earth's atmosphere. Oceans absorb about one third of the anthropogenic CO2 causing the phenomenon of ocean acidification and this comes at a huge cost to our marine environments. The CO2 is absorbed on the surface and then transferred into the deeper waters. Which causes it to be stuck for centuries before making its way back into the atmosphere. As the CO2 dissolves in seawater it causes the PH to lower. With a lowered PH water becomes more acidic. The Hydrogen ions decrease and become less active. With this process carbonic acid is formed. The ocean now is more acidic then it has ever been in the past 650,000 years. The increase in acidic levels has caused our marine life to adjust. Acidosis caused by the increase of carbonic acid in the body fluids means a lower pH in the blood. This changes is just the start to many health issues for these organism's.

Nonuniform ocean acidification and attenuation of the ocean carbon sink

NASA Astrophysics Data System (ADS)

Fassbender, Andrea J.; Sabine, Christopher L.; Palevsky, Hilary I.

2017-08-01

Surface ocean carbon chemistry is changing rapidly. Partial pressures of carbon dioxide gas (pCO2) are rising, pH levels are declining, and the ocean's buffer capacity is eroding. Regional differences in short-term pH trends primarily have been attributed to physical and biological processes; however, heterogeneous seawater carbonate chemistry may also be playing an important role. Here we use Surface Ocean CO2 Atlas Version 4 data to develop 12 month gridded climatologies of carbonate system variables and explore the coherent spatial patterns of ocean acidification and attenuation in the ocean carbon sink caused by rising atmospheric pCO2. High-latitude regions exhibit the highest pH and buffer capacity sensitivities to pCO2 increases, while the equatorial Pacific is uniquely insensitive due to a newly defined aqueous CO2 concentration effect. Importantly, dissimilar regional pH trends do not necessarily equate to dissimilar acidity ([H+]) trends, indicating that [H+] is a more useful metric of acidification.

Long-Term Experimental Acidification Drives Watershed Scale Shift in Dissolved Organic Matter Composition and Flux.

PubMed

SanClements, Michael D; Fernandez, Ivan J; Lee, Robert H; Roberti, Joshua A; Adams, Mary Beth; Rue, Garret A; McKnight, Diane M

2018-03-06

Over the last several decades dissolved organic carbon concentrations (DOC) in surface waters have increased throughout much of the northern hemisphere. Several hypotheses have been proposed regarding the drivers of this phenomenon including decreased sulfur (S) deposition working via an acidity- change mechanism. Using fluorescence spectroscopy and data from two long-term (24+ years at completion of this study) whole watershed acidification experiments, that is, the Bear Brook Watershed in Maine (BBWM) and Fernow Experimental Forest in West Virginia (FEF) allowed us to control for factors other than the acidity-change mechanism (e.g., differing vegetation, shifting climate), resulting in the first study we are aware of where the acidity change mechanism could be experimentally isolated at the whole ecosystem and decadal scales as the driver of shifts in DOM dynamics. The multidecadal record of stream chemistry at BBWM demonstrates a significantly lower DOC concentration in the treated compared to the reference watershed. Additionally, at both BBWM and FEF we found significant and sustained differences in stream fluorescence index (FI) between the treated and reference watersheds, with the reference watersheds demonstrating a stronger terrestrial DOM signature. These data, coupled with evidence of pH shifts in upper soil horizons support the hypotheses that declines in S deposition are driving changes in the solubility of soil organic matter and increased flux of terrestrial DOC to water bodies.

Leaching behaviour and environmental risk assessment of heavy metals from electronic solder in acidified soil.

PubMed

Lao, Xiaodong; Cheng, Congqian; Min, Xiaohua; Zhao, Jie; Zhou, Dayu; Li, Xiaogang

2015-11-01

The leaching behaviour of Sn and Pb elements from eutectic SnPb solder of electronic waste in acidic soil was investigated through acidification with HCl-H2SO4 solution and compared with saline solution. The amounts of Sn and Pb elements leached, when subjected to acidic soil, are higher than those with saline soil. Evidence for the significantly preferential release of Sn into the leachate is provided; the galvanic couple accelerated such preferential release. Surface product analysis reveals the slight damage of SnPb in saline soil. Serious dissolution due to electrochemical reaction and a thick, porous PbSO4 surface layer are observed in acidified soil, suggesting more severe toxicity potential of Pb in soil rather than in water.

Rapid regional recovery from sulfate and nitrate pollution in streams of the western Czech Republic - Comparison to other recovering areas

USGS Publications Warehouse

Majer, V.; Kram, P.; Shanley, J.B.

2005-01-01

Hydrochemical changes between 1991 and 2001 were assessed based on two synoptic stream surveys from the 820-km2 region of the Slavkov Forest and surrounding area, western Czech Republic. Marked declines of sulfate, nitrate, chloride, calcium and magnesium in surface waters were compared with other areas of Europe and North America recovering from acidification. Declines of sulfate concentration in the Slavkov Forest (-30 ??eq L-1 yr-1) were more dramatic than declines reported from other sites. However, these dramatic declines of strong acid anions did not generate a widespread increase of stream water pH in the Slavkov Forest. Only the most acidic streams experienced a slight increase of pH by 0.5 unit. An unexpected decline of stream water pH occurred in slightly alkaline streams. ?? 2004 Elsevier Ltd. All rights reserved.

Predicting the vulnerability of streams to episodic acidification and potential effects on aquatic biota in Shenandoah National Park, Virginia

USGS Publications Warehouse

Rice, Karen C.; Deviney, Frank A.; Hornberger, George M.; Webb, James R.

2006-01-01

Acidic deposition is one of the most serious environmental problems affecting Shenandoah National Park in north-central Virginia. The park is the third most contaminated park in the National Park System because of the deposition of acid rain. Acid rain affects headwater streams in the park by temporarily reducing the acid-neutralizing capacity (ANC) of the water, a process termed episodic acidification. In turn, the increase in acidic components in streamwater can have deleterious effects on the aquatic biota.Although acidic deposition to the park is relatively uniform across its land area, the water-quality response of streamwater during rain events varies substantially. This response is a function of the underlying geology and topographic attributes of watersheds.Geologic and topographic data for the park's 231 watersheds are readily available; however, long-term (years and tens of years) measurements of streamwater ANC and accompanying discharge are not and would be prohibitively expensive to collect. Modeled predictions of the vulnerability of the park's streams to episodic acidification are an alternative to long-term water-quality monitoring. These predictions can aid park officials in making management decisions.

Effects of seawater acidification on a coral reef meiofauna community

NASA Astrophysics Data System (ADS)

Sarmento, V. C.; Souza, T. P.; Esteves, A. M.; Santos, P. J. P.

2015-09-01

Despite the increasing risk that ocean acidification will modify benthic communities, great uncertainty remains about how this impact will affect the lower trophic levels, such as members of the meiofauna. A mesocosm experiment was conducted to investigate the effects of water acidification on a phytal meiofauna community from a coral reef. Community samples collected from the coral reef subtidal zone (Recife de Fora Municipal Marine Park, Porto Seguro, Bahia, Brazil), using artificial substrate units, were exposed to a control pH (ambient seawater) and to three levels of seawater acidification (pH reductions of 0.3, 0.6, and 0.9 units below ambient) and collected after 15 and 30 d. After 30 d of exposure, major changes in the structure of the meiofauna community were observed in response to reduced pH. The major meiofauna groups showed divergent responses to acidification. Harpacticoida and Polychaeta densities did not show significant differences due to pH. Nematoda, Ostracoda, Turbellaria, and Tardigrada exhibited their highest densities in low-pH treatments (especially at the pH reduction of 0.6 units, pH 7.5), while harpacticoid nauplii were strongly negatively affected by low pH. This community-based mesocosm study supports previous suggestions that ocean acidification induces important changes in the structure of marine benthic communities. Considering the importance of meiofauna in the food web of coral reef ecosystems, the results presented here demonstrate that the trophic functioning of coral reefs is seriously threatened by ocean acidification.

Diffusion boundary layers ameliorate the negative effects of ocean acidification on the temperate coralline macroalga Arthrocardia corymbosa.

PubMed

Cornwall, Christopher E; Boyd, Philip W; McGraw, Christina M; Hepburn, Christopher D; Pilditch, Conrad A; Morris, Jaz N; Smith, Abigail M; Hurd, Catriona L

2014-01-01

Anthropogenically-modulated reductions in pH, termed ocean acidification, could pose a major threat to the physiological performance, stocks, and biodiversity of calcifiers and may devalue their ecosystem services. Recent debate has focussed on the need to develop approaches to arrest the potential negative impacts of ocean acidification on ecosystems dominated by calcareous organisms. In this study, we demonstrate the role of a discrete (i.e. diffusion) boundary layer (DBL), formed at the surface of some calcifying species under slow flows, in buffering them from the corrosive effects of low pH seawater. The coralline macroalga Arthrocardia corymbosa was grown in a multifactorial experiment with two mean pH levels (8.05 'ambient' and 7.65 a worst case 'ocean acidification' scenario projected for 2100), each with two levels of seawater flow (fast and slow, i.e. DBL thin or thick). Coralline algae grown under slow flows with thick DBLs (i.e., unstirred with regular replenishment of seawater to their surface) maintained net growth and calcification at pH 7.65 whereas those in higher flows with thin DBLs had net dissolution. Growth under ambient seawater pH (8.05) was not significantly different in thin and thick DBL treatments. No other measured diagnostic (recruit sizes and numbers, photosynthetic metrics, %C, %N, %MgCO3) responded to the effects of reduced seawater pH. Thus, flow conditions that promote the formation of thick DBLs, may enhance the subsistence of calcifiers by creating localised hydrodynamic conditions where metabolic activity ameliorates the negative impacts of ocean acidification.

Oceanic ecosystem dynamics during gigantic volcanic episodes: the Ontong Java and Manihiki Plateaus recorded by calcareous nannoplankton. (Invited)

NASA Astrophysics Data System (ADS)

Erba, E.

2010-12-01

Earth's volcanic activity introduces environmental stress that biota are forced to survive. There is a general consensus on the role of volcanogenic carbon dioxide increases, and implicit tectonic-igneous events, triggering major climate changes and profound variations in chemical, physical and trophic characteristics of the oceans through the Phanerozoic. Cretaceous geological records indicate conditions of excess atmCO2 (up to 2000-3000 ppm) derived from construction of Large Igneous Provinces (LIPs). In such “high CO2 world” and greenhouse conditions, the deep ocean became depleted of oxygen promoting the accumulation and burial of massive amounts of organic matter; such episodes are recognized as Oceanic Anoxic Events (OAEs) and their geological records merit careful examination of how the Earth system, and Life in particular, can overcome extreme experiments of global change. The Early Aptian (˜ 120 million years ago) OAE1a is a complex example of volcanicCO2-induced environmental stress. There is a general consensus on the causes of this case-history, namely excess CO2 derived from the construction of the Ontong Java-Manihiki LIP. Multi- and inter-disciplinary studies of the OAE1a have pointed out C, O, Os, Sr isotopic anomalies, a biocalcification crisis in pelagic and neritic settings, enhanced fertility and primary productivity, as well as ocean acidification. Available cyclochronology allows high-resolution dating of biotic and environmental fluctuations, providing the precision necessary for understanding the role of volcanogenic CO2 on nannoplankton biocalcification, adaptations, evolutionary innovation and/or extinctions. The reconstructed sequence of volcanogenic CO2 pulses, and perhaps some clathrate melting, triggered a climate change to supergreenhouse conditions, anoxia and ocean acidification. The demise of heavily calcified nannoconids and reduced calcite paleofluxes marks beginning of the pre-OAE1a calcification crisis. Ephemeral coccolith dwarfism and malformation represent adjustments to survive lower pH. Deep-water acidification occurs with a delay of 25-30 thousand years: a dissolution event recording 1 to 2km shallowing of the Calcite Compensation Depth anticipated the onset of anoxic sedimentation. A major acceleration in weathering has been identified in the lowermost part of OAE1a. After acidification-dissolution climax, nannoplankton and carbonate recovery developed over ~160 kyr, under persisting global dysoxia-anoxia. This recovery presumably implies a stasis of the LIP activity and gradual buffering of ocean acidification or a decrease in volcanogenic CO2 emissions and consistently higher CO2 drawdown through Corg burial and/or weathering. Rising CO2 and surface-ocean acidification during OAE1a triggered false extinctions among calcareous nannoplankton. Conversely, a major origination episode starts approximately 1 My before global anoxia and persists through OAE1a and associated acidification. Increasing pCO2 caused complex and species-specific reactions, including production of r-strategist taxa, which, however, secreted dwarf and malformed coccoliths as a strategy to overcome acidification.

Ocean acidification impact on copepod swimming and mating behavior: consequences for population dynamics

NASA Astrophysics Data System (ADS)

Seuront, L.

2010-12-01

There is now ample evidence that ocean acidification caused by the uptake of additional carbon dioxide from the atmosphere at the ocean surface will severely impact on marine ecosystem structure and function. To date, most research effort has focused on the impact of ocean acidification on calcifying marine organisms. These include the dissolution of calcifying plankton, reduced growth and shell thickness in gastropods and echinoderms and declining growth of reef-building corals. The effects of increasing the partial pressure in carbon dioxide and decreasing carbonate concentrations on various aspects of phytoplankton biology and ecology have received some attention. It has also recently been shown that the ability of fish larvae to discriminate between the olfactory cues of different habitat types at settlement and to detect predator olfactory cues are impaired at the level of ocean acidification predicted to occur around 2100 on a business-as-usual scenario of CO2 emissions. Average ocean pH has decreased by 0.1 units since the pre-industrial times, and it is predicted to decline another 0.3-0.4 units by 2100, which nearly corresponds to a doubling PCO2. In addition, some locations are expected to exhibit an even greater than predicted rate of decline. In this context, understanding the direct and indirect links between ocean acidification and the mortality of marine species is critical, especially for minute planktonic organisms such as copepods at the base of the ocean food chains. In this context, this work tested if ocean acidification could affect copepod swimming behavior, and subsequently affect, and ultimately disrupt, the ability of male copepods to detect and follow the pheromone plume produced by conspecific females. To ensure the generality and the ecological relevance of the present work, the species used for the experimentation are two of the most common zooplankton species found in estuarine and coastal waters of the Northern Hemisphere, the calanoid copepods Eurytemora affinis and Temora longicornis. Behavioral and mating experiments were conducted under conditions of control seawater (pH = 8.1) and conditions of ocean pH expected to occur circa 2100 (i.e. pH = 7.8 to 7.6) because of present and future CO2 emissions under the SRES A2 scenario. Our results indicate that ocean acidification modifies E. affinis and T. longicornis swimming and mating behaviors, and mating success. Specifically, ocean acidification significantly (i) modifies the stochastic properties of successive displacements, leading to decrease mate encounter rates when copepods cannot rely on female pheromone plumes (i.e. under turbulent conditions) and (ii) decreases the ability of males to detect females pheromone trails, to accurately follow trails and to successfully track a female. This led to a significant decrease in contact and capture rates from control to acidified seawater. These results indicate that ocean acification decreases the ability of male copepods to detect, track and capture a female, hence suggest an overall impact on population fitness and dynamics.

Oriented acidification of wasted activated sludge (WAS) focused on odd-carbon volatile fatty acid (VFA): Regulation strategy and microbial community dynamics.

PubMed

Huang, Long; Chen, Zhiqiang; Xiong, Dandan; Wen, Qinxue; Ji, Ye

2018-06-01

As the main intermediate metabolite in anaerobic digestion of wasted activated sludge (WAS), volatile fatty acids (VFAs) are proper substrate for mixed culture (MC) polyhydroxyalkanoate (PHA) synthesis. To further optimize the performance of MC PHA production process, VFA _odd (i.e., VFA with odd carbon atoms) oriented acidification process was proposed and conducted in this study. Three regulation factors including reaction pH, fraction of added β-cyclodextrin (β-CD) and glycerol were selected and response surface methodology (RSM) was used to enhance and effectively regulate the VFA _odd production while maintaining enough acidification degree in the WAS acidification. High percentage of VFA _odd (larger than 60% and dominated by propionic acid) can be obtained in the operating condition area with glycerol addition ratio (quantified by C/N) ranging from 15 to 20 and reaction pH ranging from 8.0 to 9.5 when β-CD addition was held at zero level (0.2 g/gTSS) according to the RSM. Semi-continuous acidification and MC PHA production assays further verified the reliability and effectiveness of the VFA _odd oriented acidification strategy. Microbial function group related to propionic acid production (G prop ) was defined based on the relationships between system function and microbial community structure, and 13 frequent species were found being involved in the G prop . Roles of the group members in the oriented acidification were analyzed to understand the mechanisms of the regulation of VFA _odd production at microbial ecological level. A synergistic effect of WAS and glycerol on the VFA _odd production in the acidification process was revealed based on the ecological analysis. Copyright © 2018 Elsevier Ltd. All rights reserved.

Coral Reefs and People in a High-CO2 World: Where Can Science Make a Difference to People?

PubMed Central

Langdon, Chris; Ekstrom, Julia A.; Cooley, Sarah R.; Suatoni, Lisa; Beck, Michael W.; Brander, Luke M.; Burke, Lauretta; Cinner, Josh E.; Doherty, Carolyn; Edwards, Peter E. T.; Gledhill, Dwight; Jiang, Li-Qing; van Hooidonk, Ruben J.; Teh, Louise; Waldbusser, George G.; Ritter, Jessica

2016-01-01

Reefs and People at Risk Increasing levels of carbon dioxide in the atmosphere put shallow, warm-water coral reef ecosystems, and the people who depend upon them at risk from two key global environmental stresses: 1) elevated sea surface temperature (that can cause coral bleaching and related mortality), and 2) ocean acidification. These global stressors: cannot be avoided by local management, compound local stressors, and hasten the loss of ecosystem services. Impacts to people will be most grave where a) human dependence on coral reef ecosystems is high, b) sea surface temperature reaches critical levels soonest, and c) ocean acidification levels are most severe. Where these elements align, swift action will be needed to protect people’s lives and livelihoods, but such action must be informed by data and science. An Indicator Approach Designing policies to offset potential harm to coral reef ecosystems and people requires a better understanding of where CO2-related global environmental stresses could cause the most severe impacts. Mapping indicators has been proposed as a way of combining natural and social science data to identify policy actions even when the needed science is relatively nascent. To identify where people are at risk and where more science is needed, we map indicators of biological, physical and social science factors to understand how human dependence on coral reef ecosystems will be affected by globally-driven threats to corals expected in a high-CO2 world. Western Mexico, Micronesia, Indonesia and parts of Australia have high human dependence and will likely face severe combined threats. As a region, Southeast Asia is particularly at risk. Many of the countries most dependent upon coral reef ecosystems are places for which we have the least robust data on ocean acidification. These areas require new data and interdisciplinary scientific research to help coral reef-dependent human communities better prepare for a high CO2 world. PMID:27828972

Coral Reefs and People in a High-CO2 World: Where Can Science Make a Difference to People?

PubMed

Pendleton, Linwood; Comte, Adrien; Langdon, Chris; Ekstrom, Julia A; Cooley, Sarah R; Suatoni, Lisa; Beck, Michael W; Brander, Luke M; Burke, Lauretta; Cinner, Josh E; Doherty, Carolyn; Edwards, Peter E T; Gledhill, Dwight; Jiang, Li-Qing; van Hooidonk, Ruben J; Teh, Louise; Waldbusser, George G; Ritter, Jessica

2016-01-01

Increasing levels of carbon dioxide in the atmosphere put shallow, warm-water coral reef ecosystems, and the people who depend upon them at risk from two key global environmental stresses: 1) elevated sea surface temperature (that can cause coral bleaching and related mortality), and 2) ocean acidification. These global stressors: cannot be avoided by local management, compound local stressors, and hasten the loss of ecosystem services. Impacts to people will be most grave where a) human dependence on coral reef ecosystems is high, b) sea surface temperature reaches critical levels soonest, and c) ocean acidification levels are most severe. Where these elements align, swift action will be needed to protect people's lives and livelihoods, but such action must be informed by data and science. Designing policies to offset potential harm to coral reef ecosystems and people requires a better understanding of where CO2-related global environmental stresses could cause the most severe impacts. Mapping indicators has been proposed as a way of combining natural and social science data to identify policy actions even when the needed science is relatively nascent. To identify where people are at risk and where more science is needed, we map indicators of biological, physical and social science factors to understand how human dependence on coral reef ecosystems will be affected by globally-driven threats to corals expected in a high-CO2 world. Western Mexico, Micronesia, Indonesia and parts of Australia have high human dependence and will likely face severe combined threats. As a region, Southeast Asia is particularly at risk. Many of the countries most dependent upon coral reef ecosystems are places for which we have the least robust data on ocean acidification. These areas require new data and interdisciplinary scientific research to help coral reef-dependent human communities better prepare for a high CO2 world.

Oceanic acidification affects marine carbon pump and triggers extended marine oxygen holes.

PubMed

Hofmann, Matthias; Schellnhuber, Hans-Joachim

2009-03-03

Rising atmospheric CO(2) levels will not only drive future global mean temperatures toward values unprecedented during the whole Quaternary but will also lead to massive acidification of sea water. This constitutes by itself an anthropogenic planetary-scale perturbation that could significantly modify oceanic biogeochemical fluxes and severely damage marine biota. As a step toward the quantification of such potential impacts, we present here a simulation-model-based assessment of the respective consequences of a business-as-usual fossil-fuel-burning scenario where a total of 4,075 Petagrams of carbon is released into the atmosphere during the current millennium. In our scenario, the atmospheric pCO(2) level peaks at approximately 1,750 microatm in the year 2200 while the sea-surface pH value drops by >0.7 units on global average, inhibiting the growth of marine calcifying organisms. The study focuses on quantifying 3 major concomitant effects. The first one is a significant (climate-stabilizing) negative feedback on rising pCO(2) levels as caused by the attenuation of biogenic calcification. The second one is related to the biological carbon pump. Because mineral ballast, notably CaCO(3), is found to play a dominant role in carrying organic matter through the water column, a reduction of its export fluxes weakens the strength of the biological carbon pump. There is, however, a third effect with severe consequences: Because organic matter is oxidized in shallow waters when mineral-ballast fluxes weaken, oxygen holes (hypoxic zones) start to expand considerably in the oceans in our model world--with potentially harmful impacts on a variety of marine ecosystems.

Acid neutralization capacity measurements in surface and ground waters in the Upper River Severn, Plynlimon: from hydrograph splitting to water flow pathways

NASA Astrophysics Data System (ADS)

Neal, C.; Hill, T.; Hill, S.; Reynolds, B.

Acid Neutralization Capacity (ANC) data for ephemeral stream and shallow groundwater for the catchments of the upper River Severn show a highly heterogeneous system of within-catchment water flow pathways and chemical weathering on scales of less than 100m. Ephemeral streams draining permeable soils seem to be supplied mainly from shallow groundwater sources. For these streams, large systematic differences in pH and alkalinity occur due to the variability of the groundwater sources and variability in water residence times. However, the variability cannot be gauged on the basis of broad based physical information collected in the field as geology, catchment gradients and forest structure are very similar. In contrast, ephemeral streams draining impermeable soils are of more uniform chemistry as surface runoff is mainly supplied from the soil zone. Groundwater ANC varies considerably over space and time. In general, the groundwaters have higher ANCs than the ephemeral streams. This is due to increased chemical weathering from the inorganic materials in the lower soils and groundwater areas and possibly longer residence times. However, during the winter months the groundwater ANCs tend to be at their lowest due to additional event driven acidic soil water contributions and intermediate groundwater residence times. The results indicate the inappropriateness of a blanket approach to classifying stream vulnerability to acidification simply on the basis of soil sensitivity. However, the results may well indicate good news for the environmental management of acidic and acid sensitive systems. For example, they clearly indicate a large potential supply of weathering components within the groundwater zone to reduce or mitigate the acidifying effects of land use change and acidic deposition without the environmental needs for Aiming. Furthermore, the high variability of ephemeral stream runoff means that certain areas of catchments where there are specific problems associated with acidification can be identified for focused remediation work for the situation where liming is required. The case for focused field campaigns and caution against over reliance on blanket modelling approaches is suggested. The results negate the conventional generalizations within hydrology of how water moves through catchments to generate streamflow events (from Hortonian overland flow to catchment contributing areas).

Use of regression‐based models to map sensitivity of aquatic resources to atmospheric deposition in Yosemite National Park, USA

USGS Publications Warehouse

Clow, David W.; Nanus, Leora; Huggett, Brian

2010-01-01

An abundance of exposed bedrock, sparse soil and vegetation, and fast hydrologic flushing rates make aquatic ecosystems in Yosemite National Park susceptible to nutrient enrichment and episodic acidification due to atmospheric deposition of nitrogen (N) and sulfur (S). In this study, multiple linear regression (MLR) models were created to estimate fall‐season nitrate and acid neutralizing capacity (ANC) in surface water in Yosemite wilderness. Input data included estimated winter N deposition, fall‐season surface‐water chemistry measurements at 52 sites, and basin characteristics derived from geographic information system layers of topography, geology, and vegetation. The MLR models accounted for 84% and 70% of the variance in surface‐water nitrate and ANC, respectively. Explanatory variables (and the sign of their coefficients) for nitrate included elevation (positive) and the abundance of neoglacial and talus deposits (positive), unvegetated terrain (positive), alluvium (negative), and riparian (negative) areas in the basins. Explanatory variables for ANC included basin area (positive) and the abundance of metamorphic rocks (positive), unvegetated terrain (negative), water (negative), and winter N deposition (negative) in the basins. The MLR equations were applied to 1407 stream reaches delineated in the National Hydrography Data Set for Yosemite, and maps of predicted surface‐water nitrate and ANC concentrations were created. Predicted surface‐water nitrate concentrations were highest in small, high‐elevation cirques, and concentrations declined downstream. Predicted ANC concentrations showed the opposite pattern, except in high‐elevation areas underlain by metamorphic rocks along the Sierran Crest, which had relatively high predicted ANC (>200 μeq L−1). Maps were created to show where basin characteristics predispose aquatic resources to nutrient enrichment and acidification effects from N and S deposition. The maps can be used to help guide development of water‐quality programs designed to monitor and protect natural resources in national parks.

Devising a Coral Reef Ocean Acidification Monitoring Portfolio

NASA Astrophysics Data System (ADS)

Gledhill, D. K.; Jewett, L.

2012-12-01

Coral reef monitoring has frequently been based only on descriptive science with limited capacity to assign specific attribution to agents of change. There is a requirement to engineer a diagnostic monitoring approach that can test predictions regarding the response of coral reef ecosystems to ocean acidification, and to identify potential areas of refugia or areas of particular concern. The approach should provide the means to detect not only changes in water chemistry but also changes in coral reef community structure and function which can be anticipated based upon our current understanding of paleo-OA events, experimental findings, process investigations, and modeling projections In August, 2012 a Coral Reef Ocean Acidification Monitoring Portfolio Workshop was hosted by the NOAA Ocean Acidification Program and the National Coral Reef Institute at the Nova Southeastern University Oceanographic Center. The workshop convened researchers and project managers from around the world engaged in coral reef ecosystems ocean acidification monitoring and research. The workshop sought to define a suite of metrics to include as part of long-term coral reef monitoring efforts that can contribute to discerning specific attribution of changes in coral reef ecosystems in response to ocean acidification. This portfolio of observations should leverage existing and proposed monitoring initiatives and would be derived from a suite of chemical, biogeochemical and ecological measurements. This talk will report out on the key findings from the workshop which should include identifying the most valuable that should be integrated into long-term coral reef ecosystem monitoring that will aid in discerning changes in coral reef ecosystems in response to ocean acidification. The outcomes should provide: recommendations of the most efficient and robust ways to monitor these metrics; identified augmentations that would be required to current ocean acidification monitoring necessary to achieve these metrics; identify opportunities for immediate collaborations using existing resources that can serve to reduce the identified gaps; and help to clarify expectations for ocean acidification monitoring.

Symbiodinium mitigate the combined effects of hypoxia and acidification on a noncalcifying cnidarian.

PubMed

Klein, Shannon G; Pitt, Kylie A; Nitschke, Matthew R; Goyen, Samantha; Welsh, David T; Suggett, David J; Carroll, Anthony R

2017-09-01

Anthropogenic nutrient inputs enhance microbial respiration within many coastal ecosystems, driving concurrent hypoxia and acidification. During photosynthesis, Symbiodinium spp., the microalgal endosymbionts of cnidarians and other marine phyla, produce O 2 and assimilate CO 2 and thus potentially mitigate the exposure of the host to these stresses. However, such a role for Symbiodinium remains untested for noncalcifying cnidarians. We therefore contrasted the fitness of symbiotic and aposymbiotic polyps of a model host jellyfish (Cassiopea sp.) under reduced O 2 (~2.09 mg/L) and pH (~ 7.63) scenarios in a full-factorial experiment. Host fitness was characterized as asexual reproduction and their ability to regulate internal pH and Symbiodinium performance characterized by maximum photochemical efficiency, chla content and cell density. Acidification alone resulted in 58% more asexual reproduction of symbiotic polyps than aposymbiotic polyps (and enhanced Symbiodinium cell density) suggesting Cassiopea sp. fitness was enhanced by CO 2 -stimulated Symbiodinium photosynthetic activity. Indeed, greater CO 2 drawdown (elevated pH) was observed within host tissues of symbiotic polyps under acidification regardless of O 2 conditions. Hypoxia alone produced 22% fewer polyps than ambient conditions regardless of acidification and symbiont status, suggesting Symbiodinium photosynthetic activity did not mitigate its effects. Combined hypoxia and acidification, however, produced similar numbers of symbiotic polyps compared with aposymbiotic kept under ambient conditions, demonstrating that the presence of Symbiodinium was key for mitigating the combined effects of hypoxia and acidification on asexual reproduction. We hypothesize that this mitigation occurred because of reduced photorespiration under elevated CO 2 conditions where increased net O 2 production ameliorates oxygen debt. We show that Symbiodinium play an important role in facilitating enhanced fitness of Cassiopea sp. polyps, and perhaps also other noncalcifying cnidarian hosts, to the ubiquitous effects of ocean acidification. Importantly we highlight that symbiotic, noncalcifying cnidarians may be particularly advantaged in productive coastal waters that are subject to simultaneous hypoxia and acidification. © 2017 John Wiley & Sons Ltd.

Impact of acid and trace metals deposition on freshwater invertebrates in north-eastern Fennoscandia and Kola Peninsula

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yakovlev, V.

1996-12-31

Freshwater invertebrate communities in a total 400 lakes and streams in northeastern Norway, Finnish Lapland and the Kola Peninsula, subjected to the atmospheric deposition were studied. The severe influence of toxic heavy metals, dusts from smelters and mineral enrichment factories were found in the Kola Peninsula. The negative acidification effects on benthic communities were found in the Jarfjord (Norway), Enontekio, Ranua-Posio and Kittila-Kolari (Finnish Lapland) areas and in the Kola Peninsula (Russia). Taxa groups, known to be sensitive to acidification, such as gammarids, snails, mayflies, stone flies, were represented with few species and in a low abundance. Heavy metals accumulationmore » in biota is recorded in areas surrounding nickel smelters in the Kola Peninsula. The metal concentration invertebrates in remote areas is rather wide and depend on an air deposition, characteristics of lake catchment areas, as well as water acidity. The environmental variables, such as lake hydrological type, altitude of lakes, dominant substratum type, abundance of macrophytes and mosses in sampling area, content of pollutants in water also show significant relationships with metal concentration in invertebrates. The most severe negative effects on biota were found in waters with low pH and simultaneously contaminated by heavy metals. The biological method for estimation of simultaneously water acidification and contamination is suggested.« less

Physiological response of the cold-water coral Desmophyllum dianthus to thermal stress and ocean acidification.

PubMed

Gori, Andrea; Ferrier-Pagès, Christine; Hennige, Sebastian J; Murray, Fiona; Rottier, Cécile; Wicks, Laura C; Roberts, J Murray

2016-01-01

Rising temperatures and ocean acidification driven by anthropogenic carbon emissions threaten both tropical and temperate corals. However, the synergistic effect of these stressors on coral physiology is still poorly understood, in particular for cold-water corals. This study assessed changes in key physiological parameters (calcification, respiration and ammonium excretion) of the widespread cold-water coral Desmophyllum dianthus maintained for ∼8 months at two temperatures (ambient 12 °C and elevated 15 °C) and two pCO2 conditions (ambient 390 ppm and elevated 750 ppm). At ambient temperatures no change in instantaneous calcification, respiration or ammonium excretion rates was observed at either pCO2 levels. Conversely, elevated temperature (15 °C) significantly reduced calcification rates, and combined elevated temperature and pCO2 significantly reduced respiration rates. Changes in the ratio of respired oxygen to excreted nitrogen (O:N), which provides information on the main sources of energy being metabolized, indicated a shift from mixed use of protein and carbohydrate/lipid as metabolic substrates under control conditions, to less efficient protein-dominated catabolism under both stressors. Overall, this study shows that the physiology of D. dianthus is more sensitive to thermal than pCO2 stress, and that the predicted combination of rising temperatures and ocean acidification in the coming decades may severely impact this cold-water coral species.

Reviews and Syntheses: Ocean acidification and its potential impacts on marine ecosystems

NASA Astrophysics Data System (ADS)

Mostofa, Khan M. G.; Liu, Cong-Qiang; Zhai, WeiDong; Minella, Marco; Vione, Davide; Gao, Kunshan; Minakata, Daisuke; Arakaki, Takemitsu; Yoshioka, Takahito; Hayakawa, Kazuhide; Konohira, Eiichi; Tanoue, Eiichiro; Akhand, Anirban; Chanda, Abhra; Wang, Baoli; Sakugawa, Hiroshi

2016-03-01

Ocean acidification, a complex phenomenon that lowers seawater pH, is the net outcome of several contributions. They include the dissolution of increasing atmospheric CO2 that adds up with dissolved inorganic carbon (dissolved CO2, H2CO3, HCO3-, and CO32-) generated upon mineralization of primary producers (PP) and dissolved organic matter (DOM). The aquatic processes leading to inorganic carbon are substantially affected by increased DOM and nutrients via terrestrial runoff, acidic rainfall, increased PP and algal blooms, nitrification, denitrification, sulfate reduction, global warming (GW), and by atmospheric CO2 itself through enhanced photosynthesis. They are consecutively associated with enhanced ocean acidification, hypoxia in acidified deeper seawater, pathogens, algal toxins, oxidative stress by reactive oxygen species, and thermal stress caused by longer stratification periods as an effect of GW. We discuss the mechanistic insights into the aforementioned processes and pH changes, with particular focus on processes taking place with different timescales (including the diurnal one) in surface and subsurface seawater. This review also discusses these collective influences to assess their potential detrimental effects to marine organisms, and of ecosystem processes and services. Our review of the effects operating in synergy with ocean acidification will provide a broad insight into the potential impact of acidification itself on biological processes. The foreseen danger to marine organisms by acidification is in fact expected to be amplified by several concurrent and interacting phenomena.

Reviews and Syntheses: Ocean acidification and its potential impacts on marine ecosystems

NASA Astrophysics Data System (ADS)

Mostofa, K. M. G.; Liu, C.-Q.; Zhai, W. D.; Minella, M.; Vione, D.; Gao, K.; Minakata, D.; Arakaki, T.; Yoshioka, T.; Hayakawa, K.; Konohira, E.; Tanoue, E.; Akhand, A.; Chanda, A.; Wang, B.; Sakugawa, H.

2015-07-01

Ocean acidification, a complex phenomenon that lowers seawater pH, is the net outcome of several contributions. They include the dissolution of increasing atmospheric CO2 that adds up with dissolved inorganic carbon (dissolved CO2, H2CO3, HCO3-, and CO32-) generated upon mineralization of primary producers (PP) and dissolved organic matter (DOM). The aquatic processes leading to inorganic carbon are substantially affected by increased DOM and nutrients via terrestrial runoff, acidic rainfall, increased PP and algal blooms, nitrification, denitrification, sulfate reduction, global warming (GW), and by atmospheric CO2 itself through enhanced photosynthesis. They are consecutively associated with enhanced ocean acidification, hypoxia in acidified deeper seawater, pathogens, algal toxins, oxidative stress by reactive oxygen species, and thermal stress caused by longer stratification periods as an effect of GW. We discuss the mechanistic insights into the aforementioned processes and pH changes, with particular focus on processes taking place with different time scales (including the diurnal one) in surface and subsurface seawater. This review also discusses these collective influences to assess their potential detrimental effects to marine organisms, and of ecosystem processes and services. Our review of the effects operating in synergy with ocean acidification will provide a broad insight into the potential impact of acidification itself on biological processes. The foreseen danger to marine organisms by acidification is in fact expected to be amplified by several concurrent and interacting phenomena.

O2-MAVS: an Instrument for Measuring Oxygen Flux

DTIC Science & Technology

2010-06-01

al. (2007), “ Coral reefs under rapid climate change and ocean acidification ,” Science 318:1737-1742 [20] K.R.N. Anthony, D.I. Kline, S. Dove, and...O. Hoegh-Guldberg (2008), “ Ocean acidification causes bleaching and productivity loss in coral reef builders,” Proc. Nat. Acad. of Sci. 105:doi...deployments were made on shallow, warm-water coral reefs in La Parguera, Puerto Rico. Time series of net production obtained using the boundary

Effects on the mobility of metals from acidification caused by possible CO₂ leakage from sub-seabed geological formations.

PubMed

de Orte, Manoela Romanó; Sarmiento, Aguasanta M; Basallote, Maria Dolores; Rodríguez-Romero, Araceli; Riba, Inmaculada; Delvalls, Angel

2014-02-01

Carbon dioxide capture and storage (CCS) in submarine geological formations has been proposed as a mitigation measure for the prevention of global warming. However, leakage of CO2 to overlying sediments may occur over time, leading to various effects on ecosystems. Laboratory-scale experiments were performed, involving direct release of carbon dioxide into sediment, inside non-pressurized chambers, in order to provide data on the possible effects of CO2 leakage from geological storage sites on the fate of several metals. Marine sediments from three sites with different levels of contamination were sampled and submitted to acidification by means of CO2 injection. The experiment lasted 10 days and sediment samples were collected at the beginning and end of the experiment and pore water was extracted for metal analysis. The results revealed that mobility of metals from sediment to pore water depends on the site, metal and length of time exposed. Mobilization of the metals Al, Fe, Zn, Co, Pb and Cu increases with acidification, and this response generally increases with time of exposure to CO2 injection. The geochemical model applied suggests that acidification also influences the speciation of metals, transforming metals and metalloids, like As, into species much more toxic to biota. The data obtained from this study will be useful for calculating the potential risk of CCS activities to the marine environment. © 2013.

Acidification of Earth: An assessment across mechanisms and scales

USGS Publications Warehouse

Rice, Karen; Herman, Janet S.

2012-01-01

In this review article, anthropogenic activities that cause acidification of Earth’s air, waters, and soils are examined. Although there are many mechanisms of acidification, the focus is on the major ones, including emissions from combustion of fossil fuels and smelting of ores, mining of coal and metal ores, and application of nitrogen fertilizer to soils, by elucidating the underlying biogeochemical reactions as well as assessing the magnitude of the effects. These widespread activities have resulted in (1) increased CO2concentration in the atmosphere that acidifies the oceans; (2) acidic atmospheric deposition that acidifies soils and bodies of freshwater; (3) acid mine drainage that acidifies bodies of freshwater and groundwaters; and (4) nitrification that acidifies soils. Although natural geochemical reactions of mineral weathering and ion exchange work to buffer acidification, the slow reaction rates or the limited abundance of reactant phases are overwhelmed by the onslaught of anthropogenic acid loading. Relatively recent modifications of resource extraction and usage in some regions of the world have begun to ameliorate local acidification, but expanding use of resources in other regions is causing environmental acidification in previously unnoticed places. World maps of coal consumption, Cu mining and smelting, and N fertilizer application are presented to demonstrate the complex spatial heterogeneity of resource consumption as well as the overlap in acidifying potential derived from distinctly different phenomena. Projected population increase by country over the next four decades indicates areas with the highest potential for acidification, so enabling anticipation and planning to offset or mitigate the deleterious environmental effects associated with these global shifts in the consumption of energy, mineral, and food resources.

Acceleration of modern acidification in the South China Sea driven by anthropogenic CO2

PubMed Central

Liu, Yi; Peng, Zicheng; Zhou, Renjun; Song, Shaohua; Liu, Weiguo; You, Chen-Feng; Lin, Yen-Po; Yu, Kefu; Wu, Chung-Che; Wei, Gangjian; Xie, Luhua; Burr, George S.; Shen, Chuan-Chou

2014-01-01

Modern acidification by the uptake of anthropogenic CO2 can profoundly affect the physiology of marine organisms and the structure of ocean ecosystems. Centennial-scale global and regional influences of anthropogenic CO2 remain largely unknown due to limited instrumental pH records. Here we present coral boron isotope-inferred pH records for two periods from the South China Sea: AD 1048–1079 and AD 1838–2001. There are no significant pH differences between the first period at the Medieval Warm Period and AD 1830–1870. However, we find anomalous and unprecedented acidification during the 20th century, pacing the observed increase in atmospheric CO2. Moreover, pH value also varies in phase with inter-decadal changes in Asian Winter Monsoon intensity. As the level of atmospheric CO2 keeps rising, the coupling global warming via weakening the winter monsoon intensity could exacerbate acidification of the South China Sea and threaten this expansive shallow water marine ecosystem. PMID:24888785

Bioremediation of waste under ocean acidification: Reviewing the role of Mytilus edulis.

PubMed

Broszeit, Stefanie; Hattam, Caroline; Beaumont, Nicola

2016-02-15

Waste bioremediation is a key regulating ecosystem service, removing wastes from ecosystems through storage, burial and recycling. The bivalve Mytilus edulis is an important contributor to this service, and is used in managing eutrophic waters. Studies show that they are affected by changes in pH due to ocean acidification, reducing their growth. This is forecasted to lead to reductions in M. edulis biomass of up to 50% by 2100. Growth reduction will negatively affect the filtering capacity of each individual, potentially leading to a decrease in bioremediation of waste. This paper critically reviews the current state of knowledge of bioremediation of waste carried out by M. edulis, and the current knowledge of the resultant effect of ocean acidification on this key service. We show that the effects of ocean acidification on waste bioremediation could be a major issue and pave the way for empirical studies of the topic. Copyright © 2016 Elsevier Ltd. All rights reserved.

Acceleration of modern acidification in the South China Sea driven by anthropogenic CO2

NASA Astrophysics Data System (ADS)

Liu, Yi; Peng, Zicheng; Zhou, Renjun; Song, Shaohua; Liu, Weiguo; You, Chen-Feng; Lin, Yen-Po; Yu, Kefu; Wu, Chung-Che; Wei, Gangjian; Xie, Luhua; Burr, George S.; Shen, Chuan-Chou

2014-06-01

Modern acidification by the uptake of anthropogenic CO2 can profoundly affect the physiology of marine organisms and the structure of ocean ecosystems. Centennial-scale global and regional influences of anthropogenic CO2 remain largely unknown due to limited instrumental pH records. Here we present coral boron isotope-inferred pH records for two periods from the South China Sea: AD 1048-1079 and AD 1838-2001. There are no significant pH differences between the first period at the Medieval Warm Period and AD 1830-1870. However, we find anomalous and unprecedented acidification during the 20th century, pacing the observed increase in atmospheric CO2. Moreover, pH value also varies in phase with inter-decadal changes in Asian Winter Monsoon intensity. As the level of atmospheric CO2 keeps rising, the coupling global warming via weakening the winter monsoon intensity could exacerbate acidification of the South China Sea and threaten this expansive shallow water marine ecosystem.

Spatial characterization of acid rain stress in Canadian Shield lakes

NASA Technical Reports Server (NTRS)

Tanis, Fred J.

1986-01-01

The acidification of lake waters from airborne pollutants is of continental proportions both in North America and Europe. A major concern of the acid rain problem is the cumulative ecosystem damage to lakes and forest. The number of lakes affected in northeastern United States and on the Canadian Shield is though to be enormous. The principle objective is to examine how seasonal changes in lake water transparency are related to annual acidic load. Further, the relationship between variations in lake acidification and ecophysical units is being examined. Finally, the utility of Thematic Mapper (TM) based observations to measure seasonal changes in the optical transparency in acid lakes is being investigated.

Chronic and episodic acidification of Adirondack streams from acid rain in 2003-2005

USGS Publications Warehouse

Lawrence, G.B.; Roy, K.M.; Baldigo, Barry P.; Simonin, H.A.; Capone, S.B.; Sutherland, J.W.; Nierzwicki-Bauer, S. A.; Boylen, C.W.

2008-01-01

Limited information is available on streams in the Adirondack region of New York, although streams are more prone to acidification than the more studied Adirondack lakes. A stream assessment was therefore undertaken in the Oswegatchie and Black River drainages; an area of 4585 km2 in the western part of the Adirondack region. Acidification was evaluated with the newly developed base-cation surplus (BCS) and the conventional acid-neutralizing capacity by Gran titration (ANCG). During the survey when stream water was most acidic (March 2004), 105 of 188 streams (56%) were acidified based on the criterion of BCS < 0 ??eq L-1, whereas 29% were acidified based on an ANCG value < 0 ??eq L-1. During the survey when stream water was least acidic (August 2003), 15 of 129 streams (12%) were acidified based on the criterion of BCS < 0 ??eq L-1, whereas 5% were acidified based on ANCG value < 0 ??eq L -1. The contribution of acidic deposition to stream acidification was greater than that of strongly acidic organic acids in each of the surveys by factors ranging from approximately 2 to 5, but was greatest during spring snowmelt and least during elevated base flow in August. During snowmelt, the percentage attributable to acidic deposition was 81%, whereas during the October 2003 survey, when dissolved organic carbon (DOC) concentrations were highest, this percentage was 66%. The total length of stream reaches estimated to be prone to acidification was 718 km out of a total of 1237 km of stream reaches that were assessed. Copyright ?? 2008 by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America. All rights reserved.

Functional interaction between bicarbonate transporters and carbonic anhydrase modulates lactate uptake into mouse cardiomyocytes.

PubMed

Peetz, Jan; Barros, L Felipe; San Martín, Alejandro; Becker, Holger M

2015-07-01

Blood-derived lactate is a precious energy substrate for the heart muscle. Lactate is transported into cardiomyocytes via monocarboxylate transporters (MCTs) together with H(+), which couples lactate uptake to cellular pH regulation. In this study, we have investigated how the interplay between different acid/base transporters and carbonic anhydrases (CA), which catalyze the reversible hydration of CO2, modulates the uptake of lactate into isolated mouse cardiomyocytes. Lactate transport was estimated both as lactate-induced acidification and as changes in intracellular lactate levels measured with a newly developed Förster resonance energy transfer (FRET) nanosensor. Recordings of intracellular pH showed an increase in the rate of lactate-induced acidification when CA was inhibited by 6-ethoxy-2-benzothiazolesulfonamide (EZA), while direct measurements of lactate flux demonstrated a decrease in MCT transport activity, when CA was inhibited. The data indicate that catalytic activity of extracellular CA increases lactate uptake and counteracts intracellular lactate-induced acidification. We propose a hypothetical model, in which HCO3 (-), formed from cell-derived CO2 at the outer surface of the cardiomyocyte plasma membrane by membrane-anchored, extracellular CA, is transported into the cell via Na(+)/HCO3 (-) cotransport to counteract intracellular acidification, while the remaining H(+) stabilizes extracellular pH at the surface of the plasma membrane during MCT activity to enhance lactate influx into cardiomyocytes.

Tropical CO2 seeps reveal the impact of ocean acidification on coral reef invertebrate recruitment.

PubMed

Allen, Ro; Foggo, Andrew; Fabricius, Katharina; Balistreri, Annalisa; Hall-Spencer, Jason M

2017-11-30

Rising atmospheric CO 2 concentrations are causing ocean acidification by reducing seawater pH and carbonate saturation levels. Laboratory studies have demonstrated that many larval and juvenile marine invertebrates are vulnerable to these changes in surface ocean chemistry, but challenges remain in predicting effects at community and ecosystem levels. We investigated the effect of ocean acidification on invertebrate recruitment at two coral reef CO 2 seeps in Papua New Guinea. Invertebrate communities differed significantly between 'reference' (median pH7.97, 8.00), 'high CO 2 ' (median pH7.77, 7.79), and 'extreme CO 2 ' (median pH7.32, 7.68) conditions at each reef. There were also significant reductions in calcifying taxa, copepods and amphipods as CO 2 levels increased. The observed shifts in recruitment were comparable to those previously described in the Mediterranean, revealing an ecological mechanism by which shallow coastal systems are affected by near-future levels of ocean acidification. Copyright © 2016 Elsevier Ltd. All rights reserved.

Projections of Ocean Acidification Under the U.N. Framework Convention of Climate Change Using a Reduced-Form Climate Carbon-Cycle Model

NASA Astrophysics Data System (ADS)

Hartin, C.

2016-02-01

Ocean chemistry is quickly changing in response to continued anthropogenic emissions of carbon to the atmosphere. Mean surface ocean pH has already decreased by 0.1 units relative to the preindustrial era. We use an open-source, simple climate and carbon cycle model ("Hector") to investigate future changes in ocean acidification (pH and calcium carbonate saturations) under the climate agreement from the United Nations Convention on Climate Change Conference (UNFCCC) of Parties in Paris 2015 (COP 21). Hector is a reduced-form, very fast-executing model that can emulate the global mean climate of the CMIP5 models, as well as the inorganic carbon cycle in the upper ocean, allowing us to investigate future changes in ocean acidification. We ran Hector under three different emissions trajectories, using a sensitivity analysis approach to quantify model uncertainty and capture a range of possible ocean acidification changes. The first trajectory is a business-as-usual scenario comparable to a Representative Concentration Pathway (RCP) 8.5, the second a scenario with the COP 21 commitments enacted, and the third an idealized scenario keeping global temperature change to 2°C, comparable to a RCP 2.6. Preliminary results suggest that under the COP 21 agreements ocean pH at 2100 will decrease by 0.2 units and surface saturations of aragonite (calcite) will decrease by 0.9 (1.4) units relative to 1850. Under the COP 21 agreement the world's oceans will be committed to a degree of ocean acidification, however, these changes may be within the range of natural variability evident in some paleo records.

The Effects of Temperature and CO2-induced Acidification on Skeletal Morphology of the Tropical Reef-building Coral Siderastrea siderea

NASA Astrophysics Data System (ADS)

Cobleigh, K.

2016-02-01

Coral reefs are threatened by increasing sea surface temperatures and decreasing surface seawater pH. Although numerous experimental studies have examined the effects of these global scale stressors on corals, few have quantified the effects of temperature and acidification on coral skeletal morphology. We conducted controlled laboratory experiments to investigate the effects of temperature (25, 28, 32°C) and CO2-induced ocean acidification (pCO2 = 324, 477, 604, 2553 µatm) on skeletal morphology of the highly resilient Caribbean reef-building coral Siderastrea siderea over a 95-day interval. Post-treatment S. siderea corallites from nearshore, backreef, and forereef colonies were imaged via stereo microscopy to evaluate impact of warming and acidification on corallite height and infilling. Both an increase and decrease in temperature relative to the control (i.e., near-present-day temperatures) resulted in increased corallite height but decreased skeletal infilling. In contrast, corals reared under the lowest (i.e., pre-industrial) and highest pCO2 treatments (i.e., extreme pCO2) exhibited both decreased corallite height and skeletal infilling relative to the control. We observed no difference in corallite height or infilling across reef zones, either within or across treatments. Interestingly, the warming projected for the end of the 21st century (32°C) resulted in increased corallite height and reduced corallite infilling. Acidification projected for the same interval (pCO2 = 604 µatm) also resulted in increased corallite height and decreased infilling. Collectively, our results suggest that these two global stressors will result in S. siderea corallites that are taller yet less infilled by the end of the 21st century. Changes in S. siderea arising from warming and acificiation may exacerbate observed declines in coral health across Caribbean reef systems.

Water bicarbonate modulates the response of the shore crab Carcinus maenas to ocean acidification.

PubMed

Maus, Bastian; Bock, Christian; Pörtner, Hans-O

2018-05-23

Ocean acidification causes an accumulation of CO 2 in marine organisms and leads to shifts in acid-base parameters. Acid-base regulation in gill breathers involves a net increase of internal bicarbonate levels through transmembrane ion exchange with the surrounding water. Successful maintenance of body fluid pH depends on the functional capacity of ion-exchange mechanisms and associated energy budget. For a detailed understanding of the dependence of acid-base regulation on water parameters, we investigated the physiological responses of the shore crab Carcinus maenas to 4 weeks of ocean acidification [OA, P(CO 2 ) w  = 1800 µatm], at variable water bicarbonate levels, paralleled by changes in water pH. Cardiovascular performance was determined together with extra-(pH e ) and intracellular pH (pH i ), oxygen consumption, haemolymph CO 2 parameters, and ion composition. High water P(CO 2 ) caused haemolymph P(CO 2 ) to rise, but pH e and pH i remained constant due to increased haemolymph and cellular [HCO 3 - ]. This process was effective even under reduced seawater pH and bicarbonate concentrations. While extracellular cation concentrations increased throughout, anion levels remained constant or decreased. Despite similar levels of haemolymph pH and ion concentrations under OA, metabolic rates, and haemolymph flow were significantly depressed by 40 and 30%, respectively, when OA was combined with reduced seawater [HCO 3 - ] and pH. Our findings suggest an influence of water bicarbonate levels on metabolic rates as well as on correlations between blood flow and pH e . This previously unknown phenomenon should direct attention to pathways of acid-base regulation and their potential feedback on whole-animal energy demand, in relation with changing seawater carbonate parameters.

Camphor-mediated synthesis of carbon nanoparticles, graphitic shell encapsulated carbon nanocubes and carbon dots for bioimaging

PubMed Central

Oza, Goldie; Ravichandran, M.; Merupo, Victor-Ishrayelu; Shinde, Sachin; Mewada, Ashmi; Ramirez, Jose Tapia; Velumani, S.; Sharon, Madhuri; Sharon, Maheshwar

2016-01-01

A green method for an efficient synthesis of water-soluble carbon nanoparticles (CNPs), graphitic shell encapsulated carbon nanocubes (CNCs), Carbon dots (CDs) using Camphor (Cinnamomum camphora) is demonstrated. Here, we describe a competent molecular fusion and fission route for step-wise synthesis of CDs. Camphor on acidification and carbonization forms CNPs, which on alkaline hydrolysis form CNCs that are encapsulated by thick graphitic layers and on further reduction by sodium borohydride yielded CDs. Though excitation wavelength dependent photoluminescence is observed in all the three carbon nanostructures, CDs possess enhanced photoluminescent properties due to more defective carbonaceous structures. The surface hydroxyl and carboxyl functional groups make them water soluble in nature. They possess excellent photostability, higher quantum yield, increased absorption, decreased cytotoxicity and hence can be utilized as a proficient bio imaging agent. PMID:26905737

Camphor-mediated synthesis of carbon nanoparticles, graphitic shell encapsulated carbon nanocubes and carbon dots for bioimaging

NASA Astrophysics Data System (ADS)

Oza, Goldie; Ravichandran, M.; Merupo, Victor-Ishrayelu; Shinde, Sachin; Mewada, Ashmi; Ramirez, Jose Tapia; Velumani, S.; Sharon, Madhuri; Sharon, Maheshwar

2016-02-01

A green method for an efficient synthesis of water-soluble carbon nanoparticles (CNPs), graphitic shell encapsulated carbon nanocubes (CNCs), Carbon dots (CDs) using Camphor (Cinnamomum camphora) is demonstrated. Here, we describe a competent molecular fusion and fission route for step-wise synthesis of CDs. Camphor on acidification and carbonization forms CNPs, which on alkaline hydrolysis form CNCs that are encapsulated by thick graphitic layers and on further reduction by sodium borohydride yielded CDs. Though excitation wavelength dependent photoluminescence is observed in all the three carbon nanostructures, CDs possess enhanced photoluminescent properties due to more defective carbonaceous structures. The surface hydroxyl and carboxyl functional groups make them water soluble in nature. They possess excellent photostability, higher quantum yield, increased absorption, decreased cytotoxicity and hence can be utilized as a proficient bio imaging agent.

The extent of ocean acidification on aragonite saturation state along the Washington-Oregon continental shelf margin in late summer 2012

NASA Astrophysics Data System (ADS)

Feely, R. A.; Alin, S. R.; Hales, B. R.; Juranek, L.; Greeley, D.

2012-12-01

The Washington-Oregon continental shelf region is exposed to conditions of low aragonite saturation state during the late spring/early summer upwelling season. However, the extent of its evolution in late summer/early fall has been largely unknown. Along this continental margin, ocean acidification, upwelling, biological productivity, and respiration processes in subsurface waters are major contributors to the variability in dissolved inorganic carbon (DIC), pH and aragonite saturation state. The persistence of water with aragonite saturation state <1 on the continental shelf off Washington and Oregon has been previously identified and could have profound ecological consequences for benthic and pelagic calcifying organisms such as mussels, oysters, abalone, echinoderms, and pteropods. In the late summer of 2012 we studied the extent of acidification conditions employing shipboard cruises and profiling gliders. We conducted several large-scale chemical and hydrographic surveys of the region in order to better understand the interrelationships between these natural and human-induced processes and their effects on aragonite saturation. We will compare the results of these new surveys with our previous work in 2011 and 2007.

Extreme drought causes distinct water acidification and eutrophication in the Lower Lakes (Lakes Alexandrina and Albert), Australia

NASA Astrophysics Data System (ADS)

Li, Siyue; Bush, Richard T.; Mao, Rong; Xiong, Lihua; Ye, Chen

2017-01-01

Droughts are set to increase in frequency and magnitude with climate change and water extraction, and understanding their influence on ecosystems is urgent in the Holocene. Low rainfall across the Murray-Darling Basin (MDB) of Australia resulted in an unprecedented water level decline in the Lower Lakes (Lakes Alexandrina and Albert) at the downstream end of the river system. A comprehensive data covering pre-drought (2004-2006), drought (2007-2010) and post-drought (2010-2013) was firstly used to unravel drought effects on water quality in the contrasting main parts and margins of the two Lakes, particularly following water acidification resulting from acid sulfate soil oxidation. Salinity, nutrients and Chl-a significantly increased during the drought in the Lake main waterbody, while pH remained stable or showed minor shifts. In contrast to the Lake Alexandrina, total dissolved solid (TDS) and electrical conductivity (EC) during the post-drought more than doubled the pre-drought period in the Lake Albert as being a terminal lake system with narrow and shallow entrance. Rewetting of the exposed pyrite-containing sediment resulted in very low pH (below 3) in Lake margins, which positively contributed to salinity increases via SO42- release and limestone dissolution. Very acidic water (pH 2-3) was neutralised naturally by lake refill, but aerial limestone dosing was required for neutralisation of water acidity during the drought period. The Lower Lakes are characterized as hypereutrophic with much higher salinity, nutrient and algae concentrations than guideline levels for aquatic ecosystem. These results suggest that, in the Lower Lakes, drought could cause water quality deterioration through water acidification and increased nutrient and Chl-a concentrations, more effective water management in the lake catchment is thus crucial to prevent the similar water quality deterioration since the projected intensification of droughts. A comparative assessment on lake resilience and recovering processes should be undertaken with a post-drought monitoring program.

Effects of episodic acidification on Atlantic salmon (Salmo salar) smolts

USGS Publications Warehouse

Magee, J.A.; Obedzinski, M.; McCormick, S.D.; Kocik, J.F.

2003-01-01

The effect of episodic acidification on Atlantic salmon (Salmo salar) smolt physiology and survival in fresh water (FW) and seawater (SW) was investigated. Smolts were held in either ambient (control, pH 6.0-6.6), acidified (chronic, pH 4.4-6.1), or episodically acidified (episodic, pH reduction from control levels to pH ???5.2 for 48 h once weekly) river water for 31 days and then transferred to 34??? SW. Smolts fed little while in acidified conditions and chronic smolts did not grow in length or weight. In FW, chronic smolts experienced increases in hematocrit and plasma potassium and reductions in plasma sodium and chloride. Upon transfer to SW, chronic and episodic smolts experienced reductions in hematocrit, increases in plasma sodium, chloride, and potassium levels, and suffered mortalities. Gill Na+,K+-ATPase and citrate synthase activities were reduced by exposure to acid. For most parameters, the effect of episodic acid exposure was less than that of chronic acidification. Exposure to acidic conditions, even when short in duration and followed by a 30-h recovery period in suitable water (pH 6.5), led to a 35% mortality of smolts upon transfer to SW. This study highlights the importance of measuring and assessing sublethal stresses in FW and their ultimate effects in marine ecosystems.

Leakage of CO2 from sub-seafloor CO2 storage sites to the seabed; Impacts on sediment microorganisms and geochemical parameters during in situ and laboratory leakage experiments

NASA Astrophysics Data System (ADS)

Reigstad, L. J.; Hannisdal, B.; Hoffmann, F. U.; Sweetman, A. K.; Baumberger, T.; Eickmann, B.; Røy, H.; Thorseth, I. H.; Pedersen, R. B.

2013-12-01

Since 1996, 14 million tons of CO2 extracted from natural gas have been injected into the Utsira Formation, a saline aquifer at ~1000 m depth in the North Sea. The injected CO2 covers today an area of 4 x 2 km2. At present, there are three international treaties protecting the oceans, and all three allow CO2 storage in sub-seabed geological formations. One of these, the EU Directive 2009/31, states that monitoring must take place before, during and after CO2 storage in order to detect leakage of CO2 and significant adverse effects on the surrounding environment. However, few environmental studies have investigated the potential impacts of a CO2 leakage on the microbial life and geochemical conditions in seafloor sediment. To remedy this, we performed two experiments with abrupt CO2 acidification on the top 10 cm of the seafloor close to the North Sea storage site: 1) One laboratory CO2 acidification experiment on undisturbed sediment cores from the seafloor overlying the CO2 storage site (80 m water depth). The continuous flow of CO2 acidified seawater (pH 6.4) with 20 000 μatm pCO2 over the cores lasted for 1.5 months with sediment core terminations at regular intervals. 2) In situ CO2 acidification experiments carried out on the seafloor at 350 m water depth, with life span of 40 hours and exposure to 20 000 μatm pCO2. Both experiments showed increased O2 consumption in the water overlying the CO2 acidified sediment relative to the control sediment, indicating a rise in metabolic activity due to the treatment. After about 12 hours of acidification and throughout the laboratory experimental period, an increase in macrofauna burial activity could be seen, with dead/dying macrofauna appearing on the sediment surface. The pyrosequencing amplicon dataset obtained after bacterial and archaeal 16S rRNA amplification (RNA level) was subjected to multivariate analyses (PCA, NMDS), revealing changes in the active community on phylum, class and OTU levels. Changes were detected on all three levels in all depths investigated, but the response to acidification appeared among less-abundant prokaryotic groups in the sediment, rather than the numerically dominant groups. Quantification of the 16S rRNA genes (DNA level) indicated no increase in cell numbers in response to the treatment. However, an increase in the in situ microbial sulfate reduction rates and/or expression of marker genes for sulfate reduction (RNA level) was discovered. Analyses of marker gene expression for other prokaryotic metabolisms will be presented as well as correlations between specific organisms and geochemical parameters. Within the limitations of the experimental set up, our studies indicate that a leakage of CO2 from a sub-seafloor storage site may not dramatically change the composition of the active microbial community in the seabed sediment though we did register activity changes in some metabolisms.

Using present-day observations to detect when anthropogenic change forces surface ocean carbonate chemistry outside preindustrial bounds

NASA Astrophysics Data System (ADS)

Sutton, Adrienne J.; Sabine, Christopher L.; Feely, Richard A.; Cai, Wei-Jun; Cronin, Meghan F.; McPhaden, Michael J.; Morell, Julio M.; Newton, Jan A.; Noh, Jae-Hoon; Ólafsdóttir, Sólveig R.; Salisbury, Joseph E.; Send, Uwe; Vandemark, Douglas C.; Weller, Robert A.

2016-09-01

One of the major challenges to assessing the impact of ocean acidification on marine life is detecting and interpreting long-term change in the context of natural variability. This study addresses this need through a global synthesis of monthly pH and aragonite saturation state (Ωarag) climatologies for 12 open ocean, coastal, and coral reef locations using 3-hourly moored observations of surface seawater partial pressure of CO2 and pH collected together since as early as 2010. Mooring observations suggest open ocean subtropical and subarctic sites experience present-day surface pH and Ωarag conditions outside the bounds of preindustrial variability throughout most, if not all, of the year. In general, coastal mooring sites experience more natural variability and thus, more overlap with preindustrial conditions; however, present-day Ωarag conditions surpass biologically relevant thresholds associated with ocean acidification impacts on Mytilus californianus (Ωarag < 1.8) and Crassostrea gigas (Ωarag < 2.0) larvae in the California Current Ecosystem (CCE) and Mya arenaria larvae in the Gulf of Maine (Ωarag < 1.6). At the most variable mooring locations in coastal systems of the CCE, subseasonal conditions approached Ωarag = 1. Global and regional models and data syntheses of ship-based observations tended to underestimate seasonal variability compared to mooring observations. Efforts such as this to characterize all patterns of pH and Ωarag variability and change at key locations are fundamental to assessing present-day biological impacts of ocean acidification, further improving experimental design to interrogate organism response under real-world conditions, and improving predictive models and vulnerability assessments seeking to quantify the broader impacts of ocean acidification.

Deciphering the Boron Proxy Records of the Paleocene-Eocene Thermal Maximum

NASA Astrophysics Data System (ADS)

Hoenisch, B.; Haynes, L.; Harper, D. T.; Penman, D. E.; Holland, K.; Rosenthal, Y.; Zachos, J. C.

2016-12-01

Rapid surface ocean acidification at the PETM has been documented by pronounced decreases in the boron isotope and B/Ca proxies measured in surface dwelling planktic foraminifera (Babila et al., 2016; Penman et al., 2014). However, translating these geochemical signatures to past seawater carbonate chemistry is challenging due to the different-from-modern elemental and isotopic composition of seawater, in addition to the lack of constraints on vital effects in foraminifer species that are now extinct. While the pH decrease can be reasonably quantified from boron isotopes, the application of modern laboratory calibrations to translate the B/Ca signal yields unfeasible estimates, thus raising questions about how well we understand fundamental proxy systematics. Here we present a possible solution to this conundrum from laboratory culture experiments performed under simulated Paleocene seawater conditions, with lower [B] and [Mg], higher [Ca] and across a range of dissolved inorganic carbon and pH. These experiments suggest that raising DIC in addition to acidification amplifies the B/Ca decrease recorded in planktic foraminifera shells, thus providing an opportunity to deconvolve the B/Ca record into pH and DIC signals. Using the boron proxy records in ODP 1209 from Shatsky Rise in the Pacific Ocean as a case study, we will perform a series of sensitivity studies to better constrain the carbon perturbation at the PETM, and the long-term evolution of surface ocean chemistry from the Paleocene into the Eocene. Our results will be compared to LOSCAR model estimates of different carbon input scenarios at the PETM. Babila, T.L., Rosenthal, Y., Wright, J.D. and Miller, K.G. (2016) A continental shelf perspective of ocean acidification and temperature evolution during the Paleocene-Eocene Thermal Maximum. Geology 44, 275-278. Penman, D.E., Hönisch, B., Zeebe, R.E., Thomas, E. and Zachos, J.C. (2014) Rapid and sustained surface ocean acidification during the Paleocene-Eocene Thermal Maximum. Paleoceanography 29, 2014PA002621.

IOOS: Aiding Aquaculture Industries and Their Harvest with Near Real-Time Data

NASA Astrophysics Data System (ADS)

Kerkering, H.; Shandy Buckley; Jan Newton; Julie Thomas

2011-12-01

West Coast aquaculture accounts for over 3000 jobs and brings in over 117 million in revenue to mostly small coastal communities. Larvae recruitment and growth in these systems are very susceptible to harmful algal blooms (HABs) and acidic waters (low pH). Since 2005, aquaculturists have observed a significant reduction in shellfish larvae production and recruitment. In 2008 and 2009, the Taylor Shellfish Company (Dabob Bay, WA) observed a loss of 80% in their hatchery production. Likewise in 2008, Whiskey Creek Shellfish Company (Netarts Bay, OR) produced only 25% of their normal crop. These businesses and local scientists suspect low pH to be the culprit in the declines. In 2007, the Monterey Abalone Company suffered a 60K loss in their harvest. After contacting local scientists it was determined that the abalone crop died from a harmful algal bloom event. In response, the three West Coast Regional Associations under the U.S. Integrated Ocean Observing System (NANOOS, CeNCOOS and SCCOOS) are working in collaboration with the Ocean Science Trust, Ocean Protection Council, CA Sea Grant, NOAA National Estuarine Research Reserve Program, and the Southern California Coastal Water Research Project to develop an observing and near real-time data delivery network focused on harmful algal blooms, the Harmful Algal Bloom Monitoring Alert Program and on ocean acidification, the California Current Acidification Network. The above organizations have participated in a number of workshops with members of the aquaculture community helping to design the network. It is clear that a spatial and temporal disconnect between the data needs of both groups exists. Aquaculture experts require daily and hourly data streams in the near-shore environment with a high degree of reliability in the data but not necessarily a high degree of accuracy. Conversely, scientists collect highly accurate data in the continental shelf and oceanic environment and model predictions on decadal scales. The networks are being designed to address scientific understanding and uncertainty as well as the management needs of various stakeholder groups. Better communication and delivery of near real time data will assist aquaculture growers to predict when larvae will recruit in the natural system, when and if to relocate crops, and when to pump water in a tanks system. Though an integrated west coast observational network satellite sea surface temperature, HAB tracking systems, ocean acidification buoys, and biological monitoring programs can be pulled together into a cohesive program. A network of scientists and industry stakeholders providing and utilizing a near real time data network saves money and increases efficiency. It is not possible to prevent variability in temperature, nutrients, pH and algal blooms, but increasing understanding will lead to more accurate predictions, and ultimately, better human adaptation to the harmful economic impacts of HABs and ocean acidification.

Influences of terrestrial inorganic carbon on carbonate system in China Seas and the implication for China Seas' vulnerabilities to potentially negative effects of ocean acidification

NASA Astrophysics Data System (ADS)

Guo, X.; Zhai, W. D.; Guo, L. G.; Jiang, Z. P.; Qi, D.; Xu, Y.; Huang, X.

2017-12-01

We investigated sea surface carbonate system and ancillary parameters in the northern South China Sea (SCS), East China Sea (ECS), Yellow Sea, and Bohai Sea during a single cruise from late April to June 2011. In this transitional season between the dry/cold and wet/warm seasons, we observed ubiquitous terrestrial inorganic carbon signals in the Yellow Sea and Bohai Sea, as indicated by excess total alkalinity (TAlk) from 150 to 450 μmol kg-1 and excess Ca concentrations from 100 to 470 μmol kg-1, associated with relatively high DIC/TAlk ratios from 0.88 to 0.92. In contrast, these terrestrial inorganic carbon signals were limited to nearshore areas in the southern ECS and northern SCS. These results suggested that the Yellow Sea and Bohai Sea were dominated by terrestrial inputs all over the year, while the terrestrial signals in the southern ECS and northern SCS were highly diminished in dry seasons through water mixing with open ocean waters (likely introduced by Kuroshio). This study also showed that the terrestrial inorganic carbon inputs had diminished carbonate ion concentrations and CaCO3 saturation states in the Yellow Sea and Bohai Sea. This may contribute to recent findings that the North Yellow Sea represents one of the systems in the China seas most vulnerable to the potentially negative effects of ocean acidification.

Interactive effects of ambient acidity and salinity on thyroid function during acidic and post-acidic acclimation of air-breathing fish (Anabas testudineus Bloch).

PubMed

Peter, M C Subhash; Rejitha, V

2011-11-01

The interactive effects of ambient acidity and salinity on thyroid function are less understood in fish particularly in air-breathing fish. We, therefore, examined the thyroid function particularly the osmotic and metabolic competences of freshwater (FW) and salinity-adapted (SA; 20 ppt) air-breathing fish (Anabas testudineus) during acidic and post-acidic acclimation, i.e., during the exposure of fish to either acidified water (pH 4.2 and 5.2) for 48 h or clean water for 96 h after pre-exposure. A substantial rise in plasma T(4) occurred after acidic exposure of both FW and SA fish. Similarly, increased plasma T(3) and T(4) were found in FW fish kept for post-acidic acclimation and these suggest an involvement of THs in short-term acidic and post-acidic acclimation. Water acidification produced significant hyperglycaemia and hyperuremia in FW fish but not in SA fish. The SA fish when kept for post-acclimation, however, produced a significant hypouremia. In both FW and SA fish, gill Na(+), K(+)-ATPase activity decreased but kidney Na(+), K(+)-ATPase activity increased upon acidic acclimation. During post-acidic acclimation, gill Na(+), K(+)-ATPase activity of the FW fish showed a rise while decreasing its activity in the SA fish. Similarly, post-acidic acclimation reduced the Na(+), K(+)-ATPase activity of intestine but elevated its activity in the liver of SA fish. A higher tolerance of the SA fish to water acidification was evident in these fish as they showed tight plasma and tissue mineral status due to the ability of this fish to counteract the ion loss. In contrast, FW fish showed more sensitivity to water acidification as they loose more ions in that medium. The positive correlations of plasma THs with many tested metabolic and hydromineral indices of both FW and SA fish and also with water pH further confirm the involvement of THs in acidic and post-acidic acclimation in these fish. We conclude that thyroid function of this fish is more sensitive to environmental acidity than ambient salinity and salinity interference nullifies the toxic effect of water acidification. Copyright © 2011 Elsevier Inc. All rights reserved.

Rising trends of dissolved organic matter in drinking-water reservoirs as a result of recovery from acidification in the Ore Mts., Czech Republic.

PubMed

Oulehle, Filip; Hruska, Jakub

2009-12-01

The concentration of chemical oxygen demand (COD), a common proxy for dissolved organic matter (DOM), was measured at seven drinking-water reservoirs and four streams between 1969 and 2006. Nine of them showed significant DOM increases (median COD change +0.08 mg L(-1) yr(-1)). Several potential drivers of these trends were considered, including air temperature, rainfall, land-use and water sulfate concentration. Temperature and precipitation influenced inter-annual variations, but not long-term trends. The long-term DOM increase was significantly associated with declines of acidic deposition, especially sulfur deposition. Surface water sulfate concentrations decreased from a median of 62 mg L(-1)-27 mg L(-1) since 1980. The magnitude of DOM increase was positively correlated with average DOM concentration (R(2) = 0.79, p < 0.001). Simultaneously, DOM concentration was positively correlated with the proportion of Histosols within the catchments (R(2) = 0.79, p < 0.001). A focus on the direct removal of DOM by water treatment procedures rather than catchment remediation is needed.

Differential behavioural responses to venlafaxine exposure route, warming and acidification in juvenile fish (Argyrosomus regius).

PubMed

Maulvault, Ana Luísa; Santos, Lúcia H M L M; Paula, José Ricardo; Camacho, Carolina; Pissarra, Vasco; Fogaça, Fabiola; Barbosa, Vera; Alves, Ricardo; Ferreira, Pedro Pousão; Barceló, Damià; Rodriguez-Mozaz, Sara; Marques, António; Diniz, Mário; Rosa, Rui

2018-09-01

Antidepressants, such as venlafaxine (VFX), which are considered emerging environmental pollutants, are increasingly more present in the marine environment, and recent evidence suggest that they might have adverse effects on fish behaviour. Furthermore, altered environmental conditions associated to climate change (e.g. warming and acidification) can also have a determinant role on fish behaviour, fitness and survival. Yet, the underlying interactions between these environmental stressors (pharmaceuticals exposure and climate change) are still far from being fully understood. The aim of this study was to assess behavioural responses (in juvenile meagre (Argyrosomus regius) exposed to VFX via water ([VFX] ~20μgL -1 ) and via dietary sources ([VFX] ~160μgkg -1 dry weight), as well as to increased temperature (ΔT°C=+5°C) and high CO 2 levels (ΔpCO 2 ~1000μatm; equivalent to ΔpH=-0.4units). Overall, VFX bioaccumulation in fish plasma was enhanced under the combination of warming and acidification. VFX triggered fish exploration, whereas fish activity and shoal cohesion were reduced. Acidification alone decreased fish exploration and shoal cohesion, and reversed fish preference to turn leftwards compared to control conditions. Such alterations were further enhanced by VFX exposure. The combination of warming and acidification also reduced shoal cohesion and loss of lateralization, regardless of VFX exposure. The distinct behaviour observed when VFX contamination, acidification and warming acted alone or in combination highlighted the need to consider the likely interactive effects of seawater warming and acidification in future research regarding the toxicological aspects of chemical contaminants. Copyright © 2018. Published by Elsevier B.V.

Calcification is not the Achilles' heel of cold-water corals in an acidifying ocean.

PubMed

Rodolfo-Metalpa, Riccardo; Montagna, Paolo; Aliani, Stefano; Borghini, Mireno; Canese, Simonepietro; Hall-Spencer, Jason M; Foggo, Andy; Milazzo, Marco; Taviani, Marco; Houlbrèque, Fanny

2015-06-01

Ocean acidification is thought to be a major threat to coral reefs: laboratory evidence and CO2 seep research has shown adverse effects on many coral species, although a few are resilient. There are concerns that cold-water corals are even more vulnerable as they live in areas where aragonite saturation (Ωara ) is lower than in the tropics and is falling rapidly due to CO2 emissions. Here, we provide laboratory evidence that net (gross calcification minus dissolution) and gross calcification rates of three common cold-water corals, Caryophyllia smithii, Dendrophyllia cornigera, and Desmophyllum dianthus, are not affected by pCO2 levels expected for 2100 (pCO2  1058 μatm, Ωara 1.29), and nor are the rates of skeletal dissolution in D. dianthus. We transplanted D. dianthus to 350 m depth (pHT 8.02; pCO2  448 μatm, Ωara 2.58) and to a 3 m depth CO2 seep in oligotrophic waters (pHT 7.35; pCO2  2879 μatm, Ωara 0.76) and found that the transplants calcified at the same rates regardless of the pCO2 confirming their resilience to acidification, but at significantly lower rates than corals that were fed in aquaria. Our combination of field and laboratory evidence suggests that ocean acidification will not disrupt cold-water coral calcification although falling aragonite levels may affect other organismal physiological and/or reef community processes. © 2015 John Wiley & Sons Ltd.

Recruitment and Succession in a Tropical Benthic Community in Response to In-Situ Ocean Acidification.

PubMed

Crook, Elizabeth Derse; Kroeker, Kristy J; Potts, Donald C; Rebolledo-Vieyra, Mario; Hernandez-Terrones, Laura M; Paytan, Adina

2016-01-01

Ocean acidification is a pervasive threat to coral reef ecosystems, and our understanding of the ecological processes driving patterns in tropical benthic community development in conditions of acidification is limited. We deployed limestone recruitment tiles in low aragonite saturation (Ωarag) waters during an in-situ field experiment at Puerto Morelos, Mexico, and compared them to tiles placed in control zones over a 14-month investigation. The early stages of succession showed relatively little difference in coverage of calcifying organisms between the low Ωarag and control zones. However, after 14 months of development, tiles from the low Ωarag zones had up to 70% less cover of calcifying organisms coincident with 42% more fleshy algae than the controls. The percent cover of biofilm and turf algae was also significantly greater in the low Ωarag zones, while the number of key grazing taxa remained constant. We hypothesize that fleshy algae have a competitive edge over the primary calcified space holders, coralline algae, and that acidification leads to altered competitive dynamics between various taxa. We suggest that as acidification impacts reefs in the future, there will be a shift in community assemblages away from upright and crustose coralline algae toward more fleshy algae and turf, established in the early stages of succession.

Recruitment and Succession in a Tropical Benthic Community in Response to In-Situ Ocean Acidification

PubMed Central

Crook, Elizabeth Derse; Kroeker, Kristy J.; Potts, Donald C.; Rebolledo-Vieyra, Mario; Hernandez-Terrones, Laura M.; Paytan, Adina

2016-01-01

Ocean acidification is a pervasive threat to coral reef ecosystems, and our understanding of the ecological processes driving patterns in tropical benthic community development in conditions of acidification is limited. We deployed limestone recruitment tiles in low aragonite saturation (Ωarag) waters during an in-situ field experiment at Puerto Morelos, Mexico, and compared them to tiles placed in control zones over a 14-month investigation. The early stages of succession showed relatively little difference in coverage of calcifying organisms between the low Ωarag and control zones. However, after 14 months of development, tiles from the low Ωarag zones had up to 70% less cover of calcifying organisms coincident with 42% more fleshy algae than the controls. The percent cover of biofilm and turf algae was also significantly greater in the low Ωarag zones, while the number of key grazing taxa remained constant. We hypothesize that fleshy algae have a competitive edge over the primary calcified space holders, coralline algae, and that acidification leads to altered competitive dynamics between various taxa. We suggest that as acidification impacts reefs in the future, there will be a shift in community assemblages away from upright and crustose coralline algae toward more fleshy algae and turf, established in the early stages of succession. PMID:26784986

Effect of ocean acidification and elevated fCO2 on trace gas production by a Baltic Sea summer phytoplankton community

NASA Astrophysics Data System (ADS)

Webb, Alison L.; Leedham-Elvidge, Emma; Hughes, Claire; Hopkins, Frances E.; Malin, Gill; Bach, Lennart T.; Schulz, Kai; Crawfurd, Kate; Brussaard, Corina P. D.; Stuhr, Annegret; Riebesell, Ulf; Liss, Peter S.

2016-08-01

The Baltic Sea is a unique environment as the largest body of brackish water in the world. Acidification of the surface oceans due to absorption of anthropogenic CO2 emissions is an additional stressor facing the pelagic community of the already challenging Baltic Sea. To investigate its impact on trace gas biogeochemistry, a large-scale mesocosm experiment was performed off Tvärminne Research Station, Finland, in summer 2012. During the second half of the experiment, dimethylsulfide (DMS) concentrations in the highest-fCO2 mesocosms (1075-1333 µatm) were 34 % lower than at ambient CO2 (350 µatm). However, the net production (as measured by concentration change) of seven halocarbons analysed was not significantly affected by even the highest CO2 levels after 5 weeks' exposure. Methyl iodide (CH3I) and diiodomethane (CH2I2) showed 15 and 57 % increases in mean mesocosm concentration (3.8 ± 0.6 increasing to 4.3 ± 0.4 pmol L-1 and 87.4 ± 14.9 increasing to 134.4 ± 24.1 pmol L-1 respectively) during Phase II of the experiment, which were unrelated to CO2 and corresponded to 30 % lower Chl a concentrations compared to Phase I. No other iodocarbons increased or showed a peak, with mean chloroiodomethane (CH2ClI) concentrations measured at 5.3 (±0.9) pmol L-1 and iodoethane (C2H5I) at 0.5 (±0.1) pmol L-1. Of the concentrations of bromoform (CHBr3; mean 88.1 ± 13.2 pmol L-1), dibromomethane (CH2Br2; mean 5.3 ± 0.8 pmol L-1), and dibromochloromethane (CHBr2Cl, mean 3.0 ± 0.5 pmol L-1), only CH2Br2 showed a decrease of 17 % between Phases I and II, with CHBr3 and CHBr2Cl showing similar mean concentrations in both phases. Outside the mesocosms, an upwelling event was responsible for bringing colder, high-CO2, low-pH water to the surface starting on day t16 of the experiment; this variable CO2 system with frequent upwelling events implies that the community of the Baltic Sea is acclimated to regular significant declines in pH caused by up to 800 µatm fCO2. After this upwelling, DMS concentrations declined, but halocarbon concentrations remained similar or increased compared to measurements prior to the change in conditions. Based on our findings, with future acidification of Baltic Sea waters, biogenic halocarbon emissions are likely to remain at similar values to today; however, emissions of biogenic sulfur could significantly decrease in this region.

Pontellid copepods, Labidocera spp., affected by ocean acidification: A field study at natural CO2 seeps.

PubMed

Smith, Joy N; Richter, Claudio; Fabricius, Katharina E; Cornils, Astrid

2017-01-01

CO2 seeps in coral reefs were used as natural laboratories to study the impacts of ocean acidification on the pontellid copepod, Labidocera spp. Pontellid abundances were reduced by ∼70% under high-CO2 conditions. Biological parameters and substratum preferences of the copepods were explored to determine the underlying causes of such reduced abundances. Stage- and sex-specific copepod lengths, feeding ability, and egg development were unaffected by ocean acidification, thus changes in these physiological parameters were not the driving factor for reduced abundances under high-CO2 exposure. Labidocera spp. are demersal copepods, hence they live amongst reef substrata during the day and emerge into the water column at night. Deployments of emergence traps showed that their preferred reef substrata at control sites were coral rubble, macro algae, and turf algae. However, under high-CO2 conditions they no longer had an association with any specific substrata. Results from this study indicate that even though the biology of a copepod might be unaffected by high-CO2, Labidocera spp. are highly vulnerable to ocean acidification.

One year water chemistry monitoring of the flooding of the Meirama open pit (NW Spain)

NASA Astrophysics Data System (ADS)

Delgado, J.; Juncosa, R.; Vázquez, A.; Fernández-Bogo, S.

2009-04-01

In December, 2007, after 30 years of operations, the mine of Meirama finished the extraction of brown lignite. Starting in April 2008, the flooding of the open pit has started and this is leading to the formation of a large mining lake (~2 km2 surface and up to 180 m depth) in which surface (river and rain water) and ground waters are involved. Since the beginning of the flooding, lake waters are weekly sampled and analyzed for temperature, pH, redox, EC, TDS, TSS, DO,DIC, DOC, turbidity, alkalinity/acidity as well as nearly 40 inorganic chemical components. Stable water isotopes (deuterium and oxygen) are also being recorded. In order to better understand the dynamic chemical evolution of lake waters, the chemical characteristics of rain water as well as a series of lake tributaries and ground waters are also being measured. Since the beginning of the flooding process, the chemical quality of lake water has experienced an interesting evolution that obeys to a variety of circumstances. The silicic geologic substratum of the catchment determines that both ground and surface waters have a rather low alkalinity. Moreover, the presence of disseminated sulfides (mainly pyrite) within the schistous materials of the mine slopes and internal rock dumps provokes a significant acidic load. From April to October 2008, the lake waters had only the contribution of rain and ground waters. Since the beginning of October, a significant volume of surface waters has been derived to the mine hole. Taking pH as indicator, the first water body had a rather acidic pH (~3) which was progressively amended with the addition of a certain amount of lime to reach an upper value of ~8 by late August. The diminution in the addition of lime up to its elimination, in December, has conducted to the progressive acidification of the lake. At present, an instrumented floating deck is being deployed in the lake. This device will serve as a base point where it is planned to locate a series of instrumentation (complete weather monitoring station, multiparametric probe, sediment trap line) that will complement with depth profiles the surficial sampling performed so far.

Enhancement of the antimicrobial properties of orthorhombic molybdenum trioxide by thermal induced fracturing of the hydrates.

PubMed

Shafaei, Shahram; Van Opdenbosch, Daniel; Fey, Tobias; Koch, Marcus; Kraus, Tobias; Guggenbichler, Josef Peter; Zollfrank, Cordt

2016-01-01

The oxides of the transition metal molybdenum exhibit excellent antimicrobial properties. We present the preparation of molybdenum trioxide dihydrate (MoO3 × 2H2O) by an acidification method and demonstrate the thermal phase development and morphological evolution during and after calcination from 25 °C to 600 °C. The thermal dehydration of the material was found to proceed in two steps. Microbiological roll-on tests using Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were performed and exceptional antimicrobial activities were determined for anhydrous samples with orthorhombic lattice symmetry and a large specific surface area. The increase in the specific surface area is due to crack formation and to the loss of the hydrate water after calcination at 300 °C. The results support the proposed antimicrobial mechanism for transition metal oxides, which based on a local acidity increase as a consequence of the augmented specific surface area. Copyright © 2015 Elsevier B.V. All rights reserved.

Ocean circulation and biogeochemistry moderate interannual and decadal surface water pH changes in the Sargasso Sea

USGS Publications Warehouse

Nathalie F. Goodkin,; Bo-Shian Wang,; Chen-Feng You,; Konrad Hughen,; Prouty, Nancy G.; Bates, Nicholas; Scott Doney,

2015-01-01

The oceans absorb anthropogenic CO2 from the atmosphere, lowering surface ocean pH, a concern for calcifying marine organisms. The impact of ocean acidification is challenging to predict as each species appears to respond differently and because our knowledge of natural changes to ocean pH is limited in both time and space. Here we reconstruct 222 years of biennial seawater pH variability in the Sargasso Sea from a brain coral, Diploria labyrinthiformis. Using hydrographic data from the Bermuda Atlantic Time-series Study and the coral-derived pH record, we are able to differentiate pH changes due to surface temperature versus those from ocean circulation and biogeochemical changes. We find that ocean pH does not simply reflect atmospheric CO2 trends but rather that circulation/biogeochemical changes account for >90% of pH variability in the Sargasso Sea and more variability in the last century than would be predicted from anthropogenic uptake of CO2 alone.

Assessment of the environmental impacts of ocean acidification (OA) and carbon capture and storage (CCS) leaks using the amphipod Hyale youngi.

PubMed

Goulding, T A; De Orte, M R; Szalaj, D; Basallote, M D; DelValls, T A; Cesar, A

2017-05-01

This study aims to ascertain the effects of CO 2 induced water acidification and leaks from Carbon Capture and Storage activities on the South American amphipod Hyale youngi. A 10-day acute toxicity test was performed using sediments from two sites located inside the Santos Estuarine System. They were subjected to five pH treatments (8.1, 7.6, 7.0, 6.5, and 6.0). Metals (Cd, Cu, Cr, Pb, Ni and Zn) and the metalloid As were analyzed to determine the influence of their acidification-related mobility on the amphipods mortality. The results showed that mortality becomes significant when compared to control in pH 6.5 in the Canal de Piaçaguera sediment (contaminated) and at pH 6.0 in Ilha das Palmas sediment (reference).

Variation in the carbon cycle of the Sevastopol Bay (Black Sea)

NASA Astrophysics Data System (ADS)

Orekhova, N. A.; Konovalov, S. K.

2018-01-01

Continuous increase in CO2 inventory in the ocean results in dramatic changes in marine biogeochemistry, e.g. acidification. That is why temporal and spatial variabilities in atmospheric pCO2 and dissolved inorganic carbon, including CO2, pH and alkalinity in water, as well as organic and inorganic carbon in bottom sediments have to be studied together making possible to resolve the key features of the carbon cycle transformation. A 30% increase of pCO2 in the Sevastopol Bay for 2008 - 2016 evidences changes in the DIC components ratios and a significant decrease in the ability to absorb atmospheric CO2 by surface waters. High organic carbon content in the bottom sediments and predominance of organic carbon production in the biological pump at inner parts of the bay reveal ongoing transformation of the carbon cycle. This has negative consequences for recreation, social and economic potentials of the Sevastopol region.

Irrigation water acidification to neutralize alkalinity for nursery crop production: Substrate pH, electrical conductivity, nutrient concentrations, and plant nutrition and growth

USDA-ARS?s Scientific Manuscript database

Liming agents in irrigation water, typically associated with carbonates and bicarbonates of calcium and magnesium, contribute to water alkalinity. Repeated application of LA to container crops can cause media-solution pH to rise overtime, that uncorrected, can lead to a nutrient availability imbalan...

Degradation products from naturally aged paper leaves of a 16th-century-printed book: a spectrochemical study.

PubMed

Bronzato, Maddalena; Calvini, Paolo; Federici, Carlo; Bogialli, Sara; Favaro, Gabriella; Meneghetti, Moreno; Mba, Miriam; Brustolon, Marina; Zoleo, Alfonso

2013-07-15

In this work, we present a wide-range spectrochemical analysis of the degradation products from naturally aged paper. The samples obtained from wash waters used during the de-acidification treatment of leaves from a 16th-century-printed book were analysed through NMR, IR, Raman UV/Vis, EPR and X-ray fluorescence (XRF) spectroscopy and HPLC-MS and inductively coupled plasma (ICP) analysis. By these methods we also studied some of the previous samples treated by acidification (sample AP) and catalytic hydrogenation (sample HP). Crossing all the data, we obtained precise indications about the main functional groups occurring on the degraded, water-soluble cellulose oligomers. These results point out that the chromophores responsible for browning are conjugated carbonyl and carboxyl compounds. As a whole, we show that the analysis of wash waters, used in the usual conservation treatments of paper de-acidification, gives much valuable information about both the conservation state of the book and the degradation reactions occurring on the leaves, due to the huge amount of cellulose by-products contained in the samples. We propose therefore this procedure as a new very convenient general method to obtain precious and normally unavailable information on the cellulose degradation by-products from naturally aged paper. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Coupled heating/acidification pretreatment of chemical sludge for dewatering by using waste sulfuric acid at low temperature.

PubMed

Bian, Bo; Zhang, Limin; Zhang, Qin; Zhang, Shaopeng; Yang, Zhen; Yang, Weiben

2018-08-01

A cost-effective approach for pretreatment of chemical sludge for further dewatering, based on the idea of "using waste to treat waste", is provided. It is a coupled heating/acidification pretreatment method, where waste sulfuric acid is employed and relatively low temperatures (<100 °C) are applied. Effects of reaction time, temperature, and dosage of waste acid on dewatering performance (both dewatering speed and degree) are studied. Under the optimal conditions (reaction time: 30 min; temperature: 90 °C; waste acid dosage: 0.175 g/(g dried sludge)), the method of this work demonstrates three advantages compared to the conventional method using lime+polyacrylamide: lower moisture content of treated sludge; higher calorific value for incineration process; and lower cost. Detailed mechanism of the pretreatment for dewatering is investigated via characterizations and statistical analyses of various parameters, among which zeta potential, particle size, protein and polysaccharide contents, soluble chemical oxygen demand (SCOD), reduction of combined water and volatile suspended solid (VSS), are associated with dewatering performance. Both heating and acidification generate disintegration of cells in sludge, giving rise to two phenomena: more organic matters are released into solution and more bound water turns into free water. Meantime, the released organic polymers flocculate sludge particles, further accelerating the solid-liquid separation process. Copyright © 2018 Elsevier Ltd. All rights reserved.

Benthic infaunal community structuring in an acidified tropical estuarine system.

PubMed

Hossain, M Belal; Marshall, David J

2014-01-01

Recent studies suggest that increasing ocean acidification (OA) should have strong direct and indirect influences on marine invertebrates. While most theory and application for OA is based on relatively physically-stable oceanic ecological systems, less is known about the effects of acidification on nearshore and estuarine systems. Here, we investigated the structuring of a benthic infaunal community in a tropical estuarine system, along a steep salinity and pH gradient, arising largely from acid-sulphate groundwater inflows (Sungai Brunei Estuary, Borneo, July 2011- June 2012). Preliminary data indicate that sediment pore-water salinity (range: 8.07 - 29.6 psu) declined towards the mainland in correspondence with the above-sediment estuarine water salinity (range: 3.58 - 31.2 psu), whereas the pore-water pH (range: 6.47- 7.72) was generally lower and less variable than the estuarine water pH (range: 5.78- 8.3), along the estuary. Of the thirty six species (taxa) recorded, the polychaetes Neanthes sp., Onuphis conchylega, Nereididae sp. and the amphipod Corophiidae sp., were numerically dominant. Calcified microcrustaceans (e.g., Cyclopoida sp. and Corophiidae sp.) were abundant at all stations and there was no clear distinction in distribution pattern along the estuarine between calcified and non-calcified groups. Species richness increased seawards, though abundance (density) showed no distinct directional trend. Diversity indices were generally positively correlated (Spearman's rank correlation) with salinity and pH (p <0.05) and negatively with clay and organic matter, except for evenness values (p >0.05). Three faunistic assemblages were distinguished: (1) nereid-cyclopoid-sabellid, (2) corophiid-capitellid and (3) onuphid- nereid-capitellid. These respectively associated with lower salinity/pH and a muddy bottom, low salinity/pH and a sandy bottom, and high salinity/pH and a sandy bottom. However, CCA suggested that species distribution and community structuring is more strongly influenced by sediment particle characteristics than by the chemical properties of the water (pH and salinity). Infaunal estuarine communities, which are typically adapted to survive relatively acidic conditions, may be less exposed, less sensitive, and less vulnerable than epibenthic or pelagic communities to further acidification of above-sediment waters. These data question the extent to which all marine infaunal communities, including oceanic communities, are likely to be affected by future global CO2-driven acidification.

Economic and Environmental Analysis for Advancing Sustainable Management of Livestock Waste: A Wisconsin Case Study

EPA Science Inventory

Livestock waste may cause air quality degradation from ammonia and methane emissions, soil quality detriment from the in-excess nutrients and acidification, and water pollution issues from nutrient and pathogens runoff to the water bodies, leading to eutrophication, algal blooms,...

Influence of ambient water intrusion on coral reef acidification in the Chuuk lagoon, located in the coral-rich western Pacific Ocean

NASA Astrophysics Data System (ADS)

Ko, Young Ho; Lee, Kitack; Noh, Jae Hoon; Lee, Charity M.; Kleypas, Joan A.; Jeong, Hae Jin; Kim, Kwang Young

2016-04-01

Weekly carbonate chemistry condition data recorded between 2008 and 2014 in the Chuuk lagoon (7.3°N and 151.5°E) of the Federated States of Micronesia, located in the western Pacific Ocean, were analyzed. The results showed that, during periods of weak intrusion of ambient seawater from the surrounding open ocean, two internal biological processes (calcification and respiration) reinforced each other and together lowered the pH of the reef water for extended periods, ranging from a few to several months. The analysis indicated that reduced intrusion of ambient water is associated with periods of low wind speeds. Such conditions increase the residence time of reef water, thus promoting acidification by respiration and calcification. This phenomenon likely affects many other areas of the coral-rich western Pacific Ocean, which contains 50% of global coral reefs and in which the degree of ambient water intrusion into the atolls has been shown to be closely associated with the El Niño-Southern Oscillation-induced wind speed change.

Experimental acidification of Little Rock Lake (Wisconsin): fish research approach and early responses.

PubMed

Swenson, W A; McCormick, J H; Simonson, T D; Jensen, K M; Eaton, J G

1989-01-01

One goal of research at Little Rock Lake, Wisconsin, is to enhance understanding of lake acidification effects on warm- and cool-water fishery resources. The Little Rock Lake fish assemblage is characteristic of many acid sensitive waters in North America and is dominated by yellow perch (Percidae) and sunfishes (Centrarchidae). Analyses of reproduction, early survival and growth rates in the field were designed around the differing reproductive modes of these taxa. Complementary laboratory research on early life stages was conducted to assist in isolating direct effect mechanisms and to determine the reliability of laboratory results in predicting field response. Preliminary findings suggest that lake acidification to pH 5.6 has not influenced reproductive activity of the four most abundant fish species. However, the field results suggest that year-class failure of rock bass (Ambloplites rupestris) may be occurring due to reduced survival of early life stages. Reduced growth and food conversion efficiency of Age 0 largemouth bass (Micropterus salmoides) is also suggested. The laboratory bioassays indicate rock bass is the most acid-sensitive Little Rock Lake species tested. However, rock bass fry survival was not significantly affected until pH was reduced from 5.6 to 5.0.

Assessing anthropogenic impact on boreal lakes with historical fish species distribution data and hydrogeochemical modeling.

PubMed

Valinia, Salar; Englund, Göran; Moldan, Filip; Futter, Martyn N; Köhler, Stephan J; Bishop, Kevin; Fölster, Jens

2014-09-01

Quantifying the effects of human activity on the natural environment is dependent on credible estimates of reference conditions to define the state of the environment before the onset of adverse human impacts. In Europe, emission controls that aimed at restoring ecological status were based on hindcasts from process-based models or paleolimnological reconstructions. For instance, 1860 is used in Europe as the target for restoration from acidification concerning biological and chemical parameters. A more practical problem is that the historical states of ecosystems and their function cannot be observed directly. Therefore, we (i) compare estimates of acidification based on long-term observations of roach (Rutilus rutilus) populations with hindcast pH from the hydrogeochemical model MAGIC; (ii) discuss policy implications and possible scope for use of long-term archival data for assessing human impacts on the natural environment and (iii) present a novel conceptual model for interpreting the importance of physico-chemical and ecological deviations from reference conditions. Of the 85 lakes studied, 78 were coherently classified by both methods. In 1980, 28 lakes were classified as acidified with the MAGIC model, however, roach was present in 14 of these. In 2010, MAGIC predicted chemical recovery in 50% of the lakes, however roach only recolonized in five lakes after 1990, showing a lag between chemical and biological recovery. Our study is the first study of its kind to use long-term archival biological data in concert with hydrogeochemical modeling for regional assessments of anthropogenic acidification. Based on our results, we show how the conceptual model can be used to understand and prioritize management of physico-chemical and ecological effects of anthropogenic stressors on surface water quality. © 2014 The Authors Global Change Biology Published by John Wiley & Sons Ltd.

Executive summary - Assessing the response of Emerald Lake, an alpine watershed in Sequoia National Park, California, to acidification during snowmelt using a simple hydrochemical model

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hooper, R.P.; West, C.T.; Peters, N.E.

1990-01-01

A simple process-oriented model, called the Alpine Lake Forecaster (ALF), was constructed using data collected from the Integrated Watershed Study of Emerald Lake, Sequoia National Park, California. ALF is able to capture the basic solute patterns during snowmelt in this alpine catchment where groundwater is a minor contributor to streamflow. It includes an empirical representation of primary mineral weathering as the only alkalinity generating mechanism. During a heavy snow year, such as the one used for calibrating the model, the model accurately simulated the surface water chemical change in response to the initial ionic pulse from the snowpack and tomore » the dilution that occurs at peak snowmelt. Because the model does not consider cation exchange, it over-predicts the acidification during the initial period of snowmelt, and therefore is a conservative predictor. However, the minimum alkalinity observed in the main inflows to Emerald Lake and in the lake outflow is accurately simulated by the model. The representation of the lake as simply a missing volume with no additional chemical reactions is supported by the observation. The model predicts a change of 2 to 5 microequiv/L in the minimum alkalinity of the lake outflow during snowmelt if the deposition would have to increase between two and 18 times the current load-alkalinity of the lake; the precise increase depends on hydrologic conditions and on the pattern of solute release from the snowpack. An acidic rainstorm that exhausted the alkalinity of the lake was observed during summer 1984 after the lake had stratified, and is the likely cause of the acidification of Emerald Lake.« less

Towards predicting coral calcification responses to ocean acidification: A combined modeling and experimental approach

NASA Astrophysics Data System (ADS)

Mollica, N. R.; Guo, W.; Cohen, A. L.; Foster, G. L.; Barkley, H.

2016-02-01

Experiments show that ocean acidification is detrimental to coral calcification. Nevertheless, coral sensitivities to OA vary and the mechanism(s) underlying these variable responses are not fully understood. One hypothesis is that ocean acidification affects the ability of coral's to regulate the pH of fluid at the site of calcification. We developed a numerical model of coral calcification that simulates corals' pH regulation based on physiochemical principles and predicts the rate of calcification [1]. Here we apply this model to Palauan corals, and seek to test the model's efficacy by comparing the predicted coral calcification responses with experimental measurements. Four coral cores were collected from two sites of different pH (7.84 and 8.04 respectively). Their bulk annual calcification rates, quantified from average density and extension rate measurements, vary from .83 to 1.39 g cm-2 year-1 for the low pH site and from 0.75 to 1.21 g cm-2 year-1for the high pH site. The higher bulk calcification rates observed in corals from the low pH site contrasts the expected general decrease in calcification in low pH seawater, and differs from our model prediction. We suspect this apparent discrepancy arises because fast-calcifying corals in low pH water are able to modulate the pH of fluid at the site of calcification. We test this hypothesis using boron isotope measurements from each coral. In addition, a more accurate measurement of instantaneous calcification, considering the number of corallites per measured area and the exact surface area of each polyp's 3-dimensional calcification site is applied. [1] Guo, W. (2014). AGU Fall Meeting, Abstract B41B-0033.

Assessing anthropogenic impact on boreal lakes with historical fish species distribution data and hydrogeochemical modeling

PubMed Central

Valinia, Salar; Englund, Göran; Moldan, Filip; Futter, Martyn N; Köhler, Stephan J; Bishop, Kevin; Fölster, Jens

2014-01-01

Quantifying the effects of human activity on the natural environment is dependent on credible estimates of reference conditions to define the state of the environment before the onset of adverse human impacts. In Europe, emission controls that aimed at restoring ecological status were based on hindcasts from process-based models or paleolimnological reconstructions. For instance, 1860 is used in Europe as the target for restoration from acidification concerning biological and chemical parameters. A more practical problem is that the historical states of ecosystems and their function cannot be observed directly. Therefore, we (i) compare estimates of acidification based on long-term observations of roach (Rutilus rutilus) populations with hindcast pH from the hydrogeochemical model MAGIC; (ii) discuss policy implications and possible scope for use of long-term archival data for assessing human impacts on the natural environment and (iii) present a novel conceptual model for interpreting the importance of physico-chemical and ecological deviations from reference conditions. Of the 85 lakes studied, 78 were coherently classified by both methods. In 1980, 28 lakes were classified as acidified with the MAGIC model, however, roach was present in 14 of these. In 2010, MAGIC predicted chemical recovery in 50% of the lakes, however roach only recolonized in five lakes after 1990, showing a lag between chemical and biological recovery. Our study is the first study of its kind to use long-term archival biological data in concert with hydrogeochemical modeling for regional assessments of anthropogenic acidification. Based on our results, we show how the conceptual model can be used to understand and prioritize management of physico-chemical and ecological effects of anthropogenic stressors on surface water quality. PMID:24535943

Different ecophysiological responses of freshwater fish to warming and acidification.

PubMed

Jesus, Tiago F; Rosa, Inês C; Repolho, Tiago; Lopes, Ana R; Pimentel, Marta S; Almeida-Val, Vera M F; Coelho, Maria M; Rosa, Rui

2018-02-01

Future climate change scenarios predict threatening outcomes to biodiversity. Available empirical data concerning biological response of freshwater fish to climate change remains scarce. In this study, we investigated the physiological and biochemical responses of two Iberian freshwater fish species (Squalius carolitertii and the endangered S. torgalensis), inhabiting different climatic conditions, to projected future scenarios of warming (+3°C) and acidification (ΔpH=-0.4). Herein, metabolic enzyme activities of glycolytic (citrate synthase - CS, lactate dehydrogenase - LDH) and antioxidant (glutathione S-transferase, catalase and superoxide dismutase) pathways, as well as the heat shock response (HSR) and lipid peroxidation were determined. Our results show that, under current water pH, warming causes differential interspecific changes on LDH activity, increasing and decreasing its activity in S. carolitertii and in S. torgalensis, respectively. Furthermore, the synergistic effect of warming and acidification caused an increase in LDH activity of S. torgalensis, comparing with the warming condition. As for CS activity, acidification significantly decreased its activity in S. carolitertii whereas in S. torgalensis no significant effect was observed. These results suggest that S. carolitertii is more vulnerable to climate change, possibly as the result of its evolutionary acclimatization to milder climatic condition, while S. torgalensis evolved in the warmer Mediterranean climate. However, significant changes in HSR were observed under the combined warming and acidification (S. carolitertii) or under acidification (S. torgalensis). Our results underlie the importance of conducting experimental studies and address species endpoint responses under projected climate change scenarios to improve conservation strategies, and to safeguard endangered freshwater fish. Copyright © 2017 Elsevier Inc. All rights reserved.

Reversal of ocean acidification enhances net coral reef calcification.

PubMed

Albright, Rebecca; Caldeira, Lilian; Hosfelt, Jessica; Kwiatkowski, Lester; Maclaren, Jana K; Mason, Benjamin M; Nebuchina, Yana; Ninokawa, Aaron; Pongratz, Julia; Ricke, Katharine L; Rivlin, Tanya; Schneider, Kenneth; Sesboüé, Marine; Shamberger, Kathryn; Silverman, Jacob; Wolfe, Kennedy; Zhu, Kai; Caldeira, Ken

2016-03-17

Approximately one-quarter of the anthropogenic carbon dioxide released into the atmosphere each year is absorbed by the global oceans, causing measurable declines in surface ocean pH, carbonate ion concentration ([CO3(2-)]), and saturation state of carbonate minerals (Ω). This process, referred to as ocean acidification, represents a major threat to marine ecosystems, in particular marine calcifiers such as oysters, crabs, and corals. Laboratory and field studies have shown that calcification rates of many organisms decrease with declining pH, [CO3(2-)], and Ω. Coral reefs are widely regarded as one of the most vulnerable marine ecosystems to ocean acidification, in part because the very architecture of the ecosystem is reliant on carbonate-secreting organisms. Acidification-induced reductions in calcification are projected to shift coral reefs from a state of net accretion to one of net dissolution this century. While retrospective studies show large-scale declines in coral, and community, calcification over recent decades, determining the contribution of ocean acidification to these changes is difficult, if not impossible, owing to the confounding effects of other environmental factors such as temperature. Here we quantify the net calcification response of a coral reef flat to alkalinity enrichment, and show that, when ocean chemistry is restored closer to pre-industrial conditions, net community calcification increases. In providing results from the first seawater chemistry manipulation experiment of a natural coral reef community, we provide evidence that net community calcification is depressed compared with values expected for pre-industrial conditions, indicating that ocean acidification may already be impairing coral reef growth.

Reversal of ocean acidification enhances net coral reef calcification

NASA Astrophysics Data System (ADS)

Albright, Rebecca; Caldeira, Lilian; Hosfelt, Jessica; Kwiatkowski, Lester; MacLaren, Jana K.; Mason, Benjamin M.; Nebuchina, Yana; Ninokawa, Aaron; Pongratz, Julia; Ricke, Katharine L.; Rivlin, Tanya; Schneider, Kenneth; Sesboüé, Marine; Shamberger, Kathryn; Silverman, Jacob; Wolfe, Kennedy; Zhu, Kai; Caldeira, Ken

2016-03-01

Approximately one-quarter of the anthropogenic carbon dioxide released into the atmosphere each year is absorbed by the global oceans, causing measurable declines in surface ocean pH, carbonate ion concentration ([CO32-]), and saturation state of carbonate minerals (Ω). This process, referred to as ocean acidification, represents a major threat to marine ecosystems, in particular marine calcifiers such as oysters, crabs, and corals. Laboratory and field studies have shown that calcification rates of many organisms decrease with declining pH, [CO32-], and Ω. Coral reefs are widely regarded as one of the most vulnerable marine ecosystems to ocean acidification, in part because the very architecture of the ecosystem is reliant on carbonate-secreting organisms. Acidification-induced reductions in calcification are projected to shift coral reefs from a state of net accretion to one of net dissolution this century. While retrospective studies show large-scale declines in coral, and community, calcification over recent decades, determining the contribution of ocean acidification to these changes is difficult, if not impossible, owing to the confounding effects of other environmental factors such as temperature. Here we quantify the net calcification response of a coral reef flat to alkalinity enrichment, and show that, when ocean chemistry is restored closer to pre-industrial conditions, net community calcification increases. In providing results from the first seawater chemistry manipulation experiment of a natural coral reef community, we provide evidence that net community calcification is depressed compared with values expected for pre-industrial conditions, indicating that ocean acidification may already be impairing coral reef growth.

Analysis, fate studies and monitoring of the antifungal agent clotrimazole in the aquatic environment.

PubMed

Peschka, Manuela; Roberts, Paul H; Knepper, Thomas P

2007-10-01

The analysis and presence of clotrimazole, an antifungal agent with logK(OW) > 4, was thoroughly studied in the aquatic environment. For that reason analytical methods based on gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry were developed and validated to quantify clotrimazole with limits of quantification down to 5 and 1 ng/L, respectively. Both methods were compared in an intercalibration exercise. The complete mass-spectrometric fragmentation pattern could be elucidated with the aid of quadrupole time of flight mass spectrometry. Since clotrimazole tends to adsorb to laboratory glassware, studies on its adsorption behaviour were made to ensure the appropriate handling of water samples, e.g. pH, storage time, pretreatment of sampling vessels or material of the vials used for final extracts. The phenomena of adsorption to suspended matter were investigated while analysing different waste-water samples. Application of the methods in various investigated wastewater and surface water samples demonstrated that clotrimazole could only be detected in the low nanogram per litre range of anthropogenic influenced unfiltered water samples after acidification to pH 2.

Revegetation of Acid Rock Drainage (ARD) Producing Slope Surface Using Phosphate Microencapsulation and Artificial Soil

NASA Astrophysics Data System (ADS)

Kim, Jae Gon

2017-04-01

Oxidation of sulfides produces acid rock drainage (ARD) upon their exposure to oxidation environment by construction and mining activities. The ARD causes the acidification and metal contamination of soil, surface water and groundwater, the damage of plant, the deterioration of landscape and the reduction of slope stability. The revegetation of slope surface is one of commonly adopted strategies to reduce erosion and to increase slope stability. However, the revegetation of the ARD producing slope surface is frequently failed due to its high acidity and toxic metal content. We developed a revegetation method consisting of microencapsualtion and artificial soil in the laboratory. The revegetation method was applied on the ARD producing slope on which the revegetation using soil coverage and seeding was failed and monitored the plant growth for one year. The phosphate solution was applied on sulfide containing rock to form stable Fe-phosphate mineral on the surface of sulfide, which worked as a physical barrier to prevent contacting oxidants such as oxygen and Fe3+ ion to the sulfide surface. After the microencapsulation, two artificial soil layers were constructed. The first layer containing organic matter, dolomite powder and soil was constructed at 2 cm thickness to neutralize the rising acidic capillary water from the subsurface and to remove the dissolved oxygen from the percolating rain water. Finally, the second layer containing seeds, organic matter, nutrients and soil was constructed at 3 cm thickness on the top. After application of the method, the pH of the soil below the artificial soil layer increased and the ARD production from the rock fragments reduced. The plant growth showed an ordinary state while the plant died two month after germination for the previous revegetation trial. No soil erosion occurred from the slope during the one year field test.

Mechanochemical activation and gallium and indiaarsenides surface catalycity

NASA Astrophysics Data System (ADS)

Kirovskaya, I. A.; Mironova, E. V.; Umansky, I. V.; Brueva, O. Yu; Murashova, A. O.; Yureva, A. V.

2018-01-01

The present work has been carried out in terms of determining the possibilities for a clearer identification of the active sites nature, intermediate surface compounds nature, functional groups during adsorption and catalysis, activation of the diamond-like semiconductors surface (in particular, the AIIIBV type) based on mechanochemical studies of the “reaction medium (H2O, iso-C3H7OH) - dispersible semiconductor (GaAs, InAs)” systems. As a result, according to the read kinetic curves of dispersion in water, both acidification and alkalinization of the medium have been established and explained; increased activity of the newly formed surface has been noted; intermediate surface compounds, functional groups appearing on the real surface and under H2O adsorption conditions, adsorption and catalytic decomposition of iso-C3H7OH have been found (with explanation of the origin). The unconcealed role of coordinatively unsaturated atoms as active sites of these processes has been shown; the relative catalytic activity of the semiconductors studied has been evaluated. Practical recommendations on the preferred use of gallium arsenide in semiconductor gas analysis and semiconductor catalysis have been given in literature searches, great care should be taken in constructing both.

Downstream Warming and Headwater Acidity May Diminish Coldwater Habitat in Southern Appalachian Mountain Streams.

PubMed

McDonnell, T C; Sloat, M R; Sullivan, T J; Dolloff, C A; Hessburg, P F; Povak, N A; Jackson, W A; Sams, C

2015-01-01

Stream-dwelling species in the U.S. southern Appalachian Mountains region are particularly vulnerable to climate change and acidification. The objectives of this study were to quantify the spatial extent of contemporary suitable habitat for acid- and thermally sensitive aquatic species and to forecast future habitat loss resulting from expected temperature increases on national forest lands in the southern Appalachian Mountain region. The goal of this study was to help watershed managers identify and assess stream reaches that are potentially vulnerable to warming, acidification, or both. To our knowledge, these results represent the first regional assessment of aquatic habitat suitability with respect to the combined effects of stream water temperature and acid-base status in the United States. Statistical models were developed to predict July mean daily maximum water temperatures and air-water temperature relations to determine potential changes in future stream water temperatures. The length of stream considered suitable habitat for acid- and thermally sensitive species, based on temperature and acid neutralizing capacity thresholds of 20°C and 50 μeq/L, was variable throughout the national forests considered. Stream length displaying temperature above 20°C was generally more than five times greater than the length predicted to have acid neutralizing capacity below 50 μeq/L. It was uncommon for these two stressors to occur within the same stream segment. Results suggested that species' distributional shifts to colder, higher elevation habitats under a warming climate can be constrained by acidification of headwater streams. The approach used in this study can be applied to evaluate climate change impacts to stream water resources in other regions.

Downstream Warming and Headwater Acidity May Diminish Coldwater Habitat in Southern Appalachian Mountain Streams

PubMed Central

Jackson, W. A; Sams, C.

2015-01-01

Stream-dwelling species in the U.S. southern Appalachian Mountains region are particularly vulnerable to climate change and acidification. The objectives of this study were to quantify the spatial extent of contemporary suitable habitat for acid- and thermally sensitive aquatic species and to forecast future habitat loss resulting from expected temperature increases on national forest lands in the southern Appalachian Mountain region. The goal of this study was to help watershed managers identify and assess stream reaches that are potentially vulnerable to warming, acidification, or both. To our knowledge, these results represent the first regional assessment of aquatic habitat suitability with respect to the combined effects of stream water temperature and acid-base status in the United States. Statistical models were developed to predict July mean daily maximum water temperatures and air-water temperature relations to determine potential changes in future stream water temperatures. The length of stream considered suitable habitat for acid- and thermally sensitive species, based on temperature and acid neutralizing capacity thresholds of 20°C and 50 μeq/L, was variable throughout the national forests considered. Stream length displaying temperature above 20°C was generally more than five times greater than the length predicted to have acid neutralizing capacity below 50 μeq/L. It was uncommon for these two stressors to occur within the same stream segment. Results suggested that species’ distributional shifts to colder, higher elevation habitats under a warming climate can be constrained by acidification of headwater streams. The approach used in this study can be applied to evaluate climate change impacts to stream water resources in other regions. PMID:26247361

Ocean acidification impacts on sperm mitochondrial membrane potential bring sperm swimming behaviour near its tipping point.

PubMed

Schlegel, Peter; Binet, Monique T; Havenhand, Jonathan N; Doyle, Christopher J; Williamson, Jane E

2015-04-01

Broadcast spawning marine invertebrates are susceptible to environmental stressors such as climate change, as their reproduction depends on the successful meeting and fertilization of gametes in the water column. Under near-future scenarios of ocean acidification, the swimming behaviour of marine invertebrate sperm is altered. We tested whether this was due to changes in sperm mitochondrial activity by investigating the effects of ocean acidification on sperm metabolism and swimming behaviour in the sea urchin Centrostephanus rodgersii. We used a fluorescent molecular probe (JC-1) and flow cytometry to visualize mitochondrial activity (measured as change in mitochondrial membrane potential, MMP). Sperm MMP was significantly reduced in ΔpH -0.3 (35% reduction) and ΔpH -0.5 (48% reduction) treatments, whereas sperm swimming behaviour was less sensitive with only slight changes (up to 11% decrease) observed overall. There was significant inter-individual variability in responses of sperm swimming behaviour and MMP to acidified seawater. We suggest it is likely that sperm exposed to these changes in pH are close to their tipping point in terms of physiological tolerance to acidity. Importantly, substantial inter-individual variation in responses of sperm swimming to ocean acidification may increase the scope for selection of resilient phenotypes, which, if heritable, could provide a basis for adaptation to future ocean acidification. © 2015. Published by The Company of Biologists Ltd.

Ocean Acidification Effects on Atlantic Cod Larval Survival and Recruitment to the Fished Population

PubMed Central

Stiasny, Martina H.; Mittermayer, Felix H.; Sswat, Michael; Voss, Rüdiger; Jutfelt, Fredrik; Chierici, Melissa; Puvanendran, Velmurugu; Mortensen, Atle; Reusch, Thorsten B. H.; Clemmesen, Catriona

2016-01-01

How fisheries will be impacted by climate change is far from understood. While some fish populations may be able to escape global warming via range shifts, they cannot escape ocean acidification (OA), an inevitable consequence of the dissolution of anthropogenic carbon dioxide (CO2) emissions in marine waters. How ocean acidification affects population dynamics of commercially important fish species is critical for adapting management practices of exploited fish populations. Ocean acidification has been shown to impair fish larvae’s sensory abilities, affect the morphology of otoliths, cause tissue damage and cause behavioural changes. Here, we obtain first experimental mortality estimates for Atlantic cod larvae under OA and incorporate these effects into recruitment models. End-of-century levels of ocean acidification (~1100 μatm according to the IPCC RCP 8.5) resulted in a doubling of daily mortality rates compared to present-day CO2 concentrations during the first 25 days post hatching (dph), a critical phase for population recruitment. These results were consistent under different feeding regimes, stocking densities and in two cod populations (Western Baltic and Barents Sea stock). When mortality data were included into Ricker-type stock-recruitment models, recruitment was reduced to an average of 8 and 24% of current recruitment for the two populations, respectively. Our results highlight the importance of including vulnerable early life stages when addressing effects of climate change on fish stocks. PMID:27551924

Ocean Acidification Effects on Atlantic Cod Larval Survival and Recruitment to the Fished Population.

PubMed

Stiasny, Martina H; Mittermayer, Felix H; Sswat, Michael; Voss, Rüdiger; Jutfelt, Fredrik; Chierici, Melissa; Puvanendran, Velmurugu; Mortensen, Atle; Reusch, Thorsten B H; Clemmesen, Catriona

2016-01-01

How fisheries will be impacted by climate change is far from understood. While some fish populations may be able to escape global warming via range shifts, they cannot escape ocean acidification (OA), an inevitable consequence of the dissolution of anthropogenic carbon dioxide (CO2) emissions in marine waters. How ocean acidification affects population dynamics of commercially important fish species is critical for adapting management practices of exploited fish populations. Ocean acidification has been shown to impair fish larvae's sensory abilities, affect the morphology of otoliths, cause tissue damage and cause behavioural changes. Here, we obtain first experimental mortality estimates for Atlantic cod larvae under OA and incorporate these effects into recruitment models. End-of-century levels of ocean acidification (~1100 μatm according to the IPCC RCP 8.5) resulted in a doubling of daily mortality rates compared to present-day CO2 concentrations during the first 25 days post hatching (dph), a critical phase for population recruitment. These results were consistent under different feeding regimes, stocking densities and in two cod populations (Western Baltic and Barents Sea stock). When mortality data were included into Ricker-type stock-recruitment models, recruitment was reduced to an average of 8 and 24% of current recruitment for the two populations, respectively. Our results highlight the importance of including vulnerable early life stages when addressing effects of climate change on fish stocks.

Air-pollution emission control in China: impacts on soil acidification recovery and constraints due to drought.

PubMed

Duan, Lei; Liu, Jing; Xin, Yan; Larssen, Thorjørn

2013-10-01

The Chinese government has established compulsory targets to reduce sulfur dioxide (SO2) and nitrogen oxide (NOx) emissions by 8% and 10%, respectively, during 2010-2015. In this study, the effect of the policy was evaluated by predicting the recovery of acidified forest soil in Chongqing, an area severely impacted by acid rain in southwest China. Since precipitation has decreased significantly in this area in recent years, the impact of drought on soil acidification was also considered. A dynamic acidification model, MAGIC, was used to predict future trends in soil chemistry under different scenarios for deposition reduction as well as drought. We found that the current regulation of SO2 emission abatement did not significantly increase soil water pH values, the Ca2+ to Al3+ molar ratio (Ca/Al), or soil base saturation to the level of 2000 before 2050. NOx emission control would have less of an effect on acidification recovery, while emission reduction of particulate matter could offset the benefits of SO2 reduction by greatly decreasing the deposition of base cations, particularly Ca(2+). Continuous droughts in the future might also delay acidification recovery. Therefore, more stringent SO2 emission control should be implemented to facilitate the recovery of seriously acidified areas in China. © 2013 Elsevier B.V. All rights reserved.

Decontamination of radiological agents from drinking water infrastructure: a literature review and summary.

PubMed

Szabo, Jeff; Minamyer, Scott

2014-11-01

This report summarizes the current state of knowledge on the persistence of radiological agents on drinking water infrastructure (such as pipes) along with information on decontamination should persistence occur. Decontamination options for drinking water infrastructure have been explored for some important radiological agents (cesium, strontium and cobalt), but important data gaps remain. Although some targeted experiments have been published on cesium, strontium and cobalt persistence on drinking water infrastructure, most of the data comes from nuclear clean-up sites. Furthermore, the studies focused on drinking water systems use non-radioactive surrogates. Non-radioactive cobalt was shown to be persistent on iron due to oxidation with free chlorine in drinking water and precipitation on the iron surface. Decontamination with acidification was an effective removal method. Strontium persistence on iron was transient in tap water, but adherence to cement-mortar has been demonstrated and should be further explored. Cesium persistence on iron water infrastructure was observed when flow was stagnant, but not with water flow present. Future research suggestions focus on expanding the available cesium, strontium and cobalt persistence data to other common infrastructure materials, specifically cement-mortar. Further exploration chelating agents and low pH treatment is recommended for future decontamination studies. Published by Elsevier Ltd.

Light-stimulated cell expansion in bean (Phaseolus vulgaris L.) leaves. I. Growth can occur without photosynthesis

NASA Technical Reports Server (NTRS)

Van Volkenburgh, E.; Cleland, R. E.

1990-01-01

Cell expansion in dicotyledonous leaves is strongly stimulated by bright white light (WL), at least in part as a result of light-induced acidification of the cell walls. It has been proposed that photosynthetic reactions are required for light-stimulated transport processes across plasma membranes of leaf cells, including proton excretion. The involvement of photosynthesis in growth and wall acidification of primary leaves of bean has been tested by inhibiting photosynthesis in two ways: by reducing chlorophyll content of intact plants with tentoxin (TX) and by treating leaf discs with 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU). Exposure to bright WL stimulated growth of intact leaves of TX-treated plants. Discs excised from green as well as from TX-or DCMU-treated leaves also responded by growing faster in WL, as long as exogenous sucrose was supplied to the photosynthetically inhibited tissues. The WL caused acidification of the epidermal surface of intact TX-leaves, but acidification of the incubation medium by mesophyll cells only occurred when photosynthesis was not inhibited. It is concluded that light-stimulated cell enlargement of bean leaves, and the necessary acidification of epidermal cell walls, are mediated by a pigment other than chlorophyll. Light-induced proton excretion by mesophyll cells, on the other hand, may require both a photosynthetic product (or exogenous sugars) and a non-photosynthetic light effect.

Interactive Effects of Seawater Acidification and Elevated Temperature on the Transcriptome and Biomineralization in the Pearl Oyster Pinctada fucata.

PubMed

Li, Shiguo; Huang, Jingliang; Liu, Chuang; Liu, Yangjia; Zheng, Guilan; Xie, Liping; Zhang, Rongqing

2016-02-02

Interactive effects of ocean acidification and ocean warming on marine calcifiers vary among species, but little is known about the underlying mechanisms. The present study investigated the combined effects of seawater acidification and elevated temperature (ambient condition: pH 8.1 × 23 °C, stress conditions: pH 7.8 × 23 °C, pH 8.1 × 28 °C, and pH 7.8 × 28 °C, exposure time: two months) on the transcriptome and biomineralization of the pearl oyster Pinctada fucata, which is an important marine calcifier. Transcriptome analyses indicated that P. fucata implemented a compensatory acid-base mechanism, metabolic depression and positive physiological responses to mitigate the effects of seawater acidification alone. These responses were energy-expensive processes, leading to decreases in the net calcification rate, shell surface calcium and carbon content, and changes in the shell ultrastructure. Elevated temperature (28 °C) within the thermal window of P. fucata did not induce significant enrichment of the sequenced genes and conversely facilitated calcification, which was detected to alleviate the negative effects of seawater acidification on biomineralization and the shell ultrastructure. Overall, this study will help elucidate the mechanisms by which pearl oysters respond to changing seawater conditions and predict the effects of global climate change on pearl aquaculture.

Ocean acidification buffering effects of seagrass in Tampa Bay

USGS Publications Warehouse

Yates, Kimberly K.; Moyer, Ryan P.; Moore, Christopher; Tomasko, David A.; Smiley, Nathan A.; Torres-Garcia, Legna; Powell, Christina E.; Chappel, Amanda R.; Bociu, Ioana; Smiley, Nathan; Torres-Garcia, Legna M.; Powell, Christina E.; Chappel, Amanda R.; Bociu, Ioana

2016-01-01

The Intergovernmental Panel on Climate Change has identified ocean acidification as a critical threat to marine and estuarine species in ocean and coastal ecosystems around the world. However, seagrasses are projected to benefit from elevated atmospheric pCO2, are capable of increasing seawater pH and carbonate mineral saturation states through photosynthesis, and may help buffer against the chemical impacts of ocean acidification. Additionally, dissolution of carbonate sediments may also provide a mechanism for buffering seawater pH. Long-term water quality monitoring data from the Environmental Protection Commission of Hillsborough County indicates that seawater pH has risen since the 1980‘s as seagrass beds have continued to recover since that time. We examined the role of seagrass beds in maintaining and elevating pH and carbonate mineral saturation state in northern and southern Tampa Bay where the percent of carbonate sediments is low (<3%) and high (>40%), respectively. Basic water quality and carbonate system parameters (including pH, total alkalinity, dissolved inorganic carbon, partial pressure of CO2, and carbonate mineral saturation state) were measured over diurnal time periods along transects (50-100 m) including dense and sparse Thalassia testudinum. seagrass beds, deep edge seagrass, and adjacent bare sand bottom. Seagrass density and productivity, sediment composition and hydrodynamic parameters were also measured, concurrently. Results indicate that seagrass beds locally elevate pH by up to 0.5 pH unit and double carbonate mineral saturation states relative to bare sand habitats. Thus, seagrass beds in Tampa Bay may provide refuge for marine organisms from the impacts of ocean acidification.

Impacts of ocean acidification on coral calcification: experimental results from a field study around submarine springs

NASA Astrophysics Data System (ADS)

Paytan, A.; Martínez Fernández, A.; Varona, N.

2017-12-01

Reef building corals are facing the effects of ocean acidification on calcification. Atmospheric carbon dioxide dissolves into the oceans and decreases the pH and the availability of carbonate ions in seawater. Carbonate ions are used by calcifying corals to create their calcium carbonate exoskeletons in the form of aragonite. As carbon dioxide emissions increase, corals may have problems precipitating their aragonite skeleton in low carbonate saturation seawater. Natural submarine groundwater springs discharge low pH seawater into the Caribbean Sea, in the Yucatan Peninsula (Mexico). These submarine springs serve as a natural laboratory to study the effects of low aragonite saturation water on coral growth. Here we show the skeletal growth parameters of three coral species under an in situ ocean acidification experiment. Nubbins of Porites porites, Porites astreoides and Siderastrea radians were collected at low pH springs and control sites and reciprocally transplanted into a low pH discharge site and into a control site not impacted by discharge. After two years, the nubbins were collected and linear extension, density and calcification rates were analyzed. Preliminary results show that coral skeleton density is significantly lower in corals transplanted into the low pH than in corals transplanted in control sites. Infaunal bioerosion is present in corals deployed at low pH sites. In contrast, linear extension and hence calcification rates do not seem to show a significant difference among sites. However, the coral species show diverse calcification responses under ocean acidification conditions, suggesting some species may be more vulnerable than others to a change in water chemistry.

Irrigation water acidification to neutralize alkalinity for nursery crop production: Substrate pH, electrical conductivity, and nutrient concentrations; and plant nutrition and growth

USDA-ARS?s Scientific Manuscript database

Liming agents (LA) in irrigation water, typically associated with carbonates and bicarbonates of calcium (Ca) and magnesium (Mg), contribute to water alkalinity. Repeated application of LA to container crops can cause media-solution pH to rise overtime, that uncorrected, can lead to a nutrient avail...

Carbonic anhydrase inhibitors modify intracellular pH transients and contractions of rat middle cerebral arteries during CO2/HCO3- fluctuations.

PubMed

Rasmussen, Jacob K; Boedtkjer, Ebbe

2018-03-01

The CO 2 /HCO 3 - buffer minimizes pH changes in response to acid-base loads, HCO 3 - provides substrate for Na + ,HCO 3 - -cotransporters and Cl - /HCO 3 - -exchangers, and H + and HCO 3 - modify vasomotor responses during acid-base disturbances. We show here that rat middle cerebral arteries express cytosolic, mitochondrial, extracellular, and secreted carbonic anhydrase isoforms that catalyze equilibration of the CO 2 /HCO 3 - buffer. Switching from CO 2 /HCO 3 - -free to CO 2 /HCO 3 - -containing extracellular solution results in initial intracellular acidification due to hydration of CO 2 followed by gradual alkalinization due to cellular HCO 3 - uptake. Carbonic anhydrase inhibition decelerates the initial acidification and attenuates the associated transient vasoconstriction without affecting intracellular pH or artery tone at steady-state. Na + ,HCO 3 - -cotransport and Na + /H + -exchange activity after NH 4 + -prepulse-induced intracellular acidification are unaffected by carbonic anhydrase inhibition. Extracellular surface pH transients induced by transmembrane NH 3 flux are evident under CO 2 /HCO 3 - -free conditions but absent when the buffer capacity and apparent H + mobility increase in the presence of CO 2 /HCO 3 - even after the inhibition of carbonic anhydrases. We conclude that (a) intracellular carbonic anhydrase activity accentuates pH transients and vasoconstriction in response to acute elevations of pCO 2 , (b) CO 2 /HCO 3 - minimizes extracellular surface pH transients without requiring carbonic anhydrase activity, and (c) carbonic anhydrases are not rate limiting for acid-base transport across cell membranes during recovery from intracellular acidification.

Major cellular and physiological impacts of ocean acidification on a reef building coral.

PubMed

Kaniewska, Paulina; Campbell, Paul R; Kline, David I; Rodriguez-Lanetty, Mauricio; Miller, David J; Dove, Sophie; Hoegh-Guldberg, Ove

2012-01-01

As atmospheric levels of CO(2) increase, reef-building corals are under greater stress from both increased sea surface temperatures and declining sea water pH. To date, most studies have focused on either coral bleaching due to warming oceans or declining calcification due to decreasing oceanic carbonate ion concentrations. Here, through the use of physiology measurements and cDNA microarrays, we show that changes in pH and ocean chemistry consistent with two scenarios put forward by the Intergovernmental Panel on Climate Change (IPCC) drive major changes in gene expression, respiration, photosynthesis and symbiosis of the coral, Acropora millepora, before affects on biomineralisation are apparent at the phenotype level. Under high CO(2) conditions corals at the phenotype level lost over half their Symbiodinium populations, and had a decrease in both photosynthesis and respiration. Changes in gene expression were consistent with metabolic suppression, an increase in oxidative stress, apoptosis and symbiont loss. Other expression patterns demonstrate upregulation of membrane transporters, as well as the regulation of genes involved in membrane cytoskeletal interactions and cytoskeletal remodeling. These widespread changes in gene expression emphasize the need to expand future studies of ocean acidification to include a wider spectrum of cellular processes, many of which may occur before impacts on calcification.

Major Cellular and Physiological Impacts of Ocean Acidification on a Reef Building Coral

PubMed Central

Kaniewska, Paulina; Campbell, Paul R.; Kline, David I.; Rodriguez-Lanetty, Mauricio; Miller, David J.

2012-01-01

As atmospheric levels of CO2 increase, reef-building corals are under greater stress from both increased sea surface temperatures and declining sea water pH. To date, most studies have focused on either coral bleaching due to warming oceans or declining calcification due to decreasing oceanic carbonate ion concentrations. Here, through the use of physiology measurements and cDNA microarrays, we show that changes in pH and ocean chemistry consistent with two scenarios put forward by the Intergovernmental Panel on Climate Change (IPCC) drive major changes in gene expression, respiration, photosynthesis and symbiosis of the coral, Acropora millepora, before affects on biomineralisation are apparent at the phenotype level. Under high CO2 conditions corals at the phenotype level lost over half their Symbiodinium populations, and had a decrease in both photosynthesis and respiration. Changes in gene expression were consistent with metabolic suppression, an increase in oxidative stress, apoptosis and symbiont loss. Other expression patterns demonstrate upregulation of membrane transporters, as well as the regulation of genes involved in membrane cytoskeletal interactions and cytoskeletal remodeling. These widespread changes in gene expression emphasize the need to expand future studies of ocean acidification to include a wider spectrum of cellular processes, many of which may occur before impacts on calcification. PMID:22509341

Reef-scale modeling of coral calcification responses to ocean acidification and sea-level rise

NASA Astrophysics Data System (ADS)

Nakamura, Takashi; Nadaoka, Kazuo; Watanabe, Atsushi; Yamamoto, Takahiro; Miyajima, Toshihiro; Blanco, Ariel C.

2018-03-01

To predict coral responses to future environmental changes at the reef scale, the coral polyp model (Nakamura et al. in Coral Reefs 32:779-794, 2013), which reconstructs coral responses to ocean acidification, flow conditions and other factors, was incorporated into a reef-scale three-dimensional hydrodynamic-biogeochemical model. This coupled reef-scale model was compared to observations from the Shiraho fringing reef, Ishigaki Island, Japan, where the model accurately reconstructed spatiotemporal variation in reef hydrodynamic and geochemical parameters. The simulated coral calcification rate exhibited high spatial variation, with lower calcification rates in the nearshore and stagnant water areas due to isolation of the inner reef at low tide, and higher rates on the offshore side of the inner reef flat. When water is stagnant, bottom shear stress is low at night and thus oxygen diffusion rate from ambient water to the inside of the coral polyp limits respiration rate. Thus, calcification decreases because of the link between respiration and calcification. A scenario analysis was conducted using the reef-scale model with several pCO2 and sea-level conditions based on IPCC (Climate change 2013: the physical science basis. Contribution of working group I to the fifth assessment report of the intergovernmental panel on climate change, Cambridge University Press, Cambridge, 2013) scenarios. The simulation indicated that the coral calcification rate decreases with increasing pCO2. On the other hand, sea-level rise increases the calcification rate, particularly in the nearshore and the areas where water is stagnant at low tide under present conditions, as mass exchange, especially oxygen exchange at night, is enhanced between the corals and their ambient seawater due to the reduced stagnant period. When both pCO2 increase and sea-level rise occur concurrently, the calcification rate generally decreases due to the effects of ocean acidification. However, the calcification rate in some inner-reef areas will increase because the positive effects of sea-level rise offset the negative effects of ocean acidification, and total calcification rate will be positive only under the best-case scenario (RCP 2.6).

Understanding the nature of atmospheric acid processing of mineral dusts in supplying bioavailable phosphorus to the oceans.

PubMed

Stockdale, Anthony; Krom, Michael D; Mortimer, Robert J G; Benning, Liane G; Carslaw, Kenneth S; Herbert, Ross J; Shi, Zongbo; Myriokefalitakis, Stelios; Kanakidou, Maria; Nenes, Athanasios

2016-12-20

Acidification of airborne dust particles can dramatically increase the amount of bioavailable phosphorus (P) deposited on the surface ocean. Experiments were conducted to simulate atmospheric processes and determine the dissolution behavior of P compounds in dust and dust precursor soils. Acid dissolution occurs rapidly (seconds to minutes) and is controlled by the amount of H + ions present. For H + < 10 -4 mol/g of dust, 1-10% of the total P is dissolved, largely as a result of dissolution of surface-bound forms. At H + > 10 -4 mol/g of dust, the amount of P (and calcium) released has a direct proportionality to the amount of H + consumed until all inorganic P minerals are exhausted and the final pH remains acidic. Once dissolved, P will stay in solution due to slow precipitation kinetics. Dissolution of apatite-P (Ap-P), the major mineral phase in dust (79-96%), occurs whether calcium carbonate (calcite) is present or not, although the increase in dissolved P is greater if calcite is absent or if the particles are externally mixed. The system was modeled adequately as a simple mixture of Ap-P and calcite. P dissolves readily by acid processes in the atmosphere in contrast to iron, which dissolves more slowly and is subject to reprecipitation at cloud water pH. We show that acidification can increase bioavailable P deposition over large areas of the globe, and may explain much of the previously observed patterns of variability in leachable P in oceanic areas where primary productivity is limited by this nutrient (e.g., Mediterranean).

Exploring the distance between nitrogen and phosphorus limitation in mesotrophic surface waters using a sensitive bioassay

NASA Astrophysics Data System (ADS)

Hrustić, Enis; Lignell, Risto; Riebesell, Ulf; Frede Thingstad, Tron

2017-01-01

The balance in microbial net consumption of nitrogen and phosphorus was investigated in samples collected in two mesotrophic coastal environments: the Baltic Sea (Tvärminne field station) and the North Sea (Espegrend field station). For this, we have refined a bioassay based on the response in alkaline phosphatase activity (APA) over a matrix of combinations in nitrogen and phosphorus additions. This assay not only provides information on which element (N or P) is the primary limiting nutrient, but also gives a quantitative estimate for the excess of the secondary limiting element (P+ or N+, respectively), as well as the ratio of balanced net consumption of added N and P over short timescales (days). As expected for a Baltic Sea late spring-early summer situation, the Tvärminne assays (n = 5) indicated N limitation with an average P+ = 0.30 ± 0.10 µM-P, when incubated for 4 days. For short incubations (1-2 days), the Espegrend assays indicated P limitation, but the shape of the response surface changed with incubation time, resulting in a drift in parameter estimates toward N limitation. Extrapolating back to zero incubation time gave P limitation with N+ ≈ 0.9 µM-N. The N : P ratio (molar) of nutrient net consumption varied considerably between investigated locations: from 2.3 ± 0.4 in the Tvärminne samples to 13 ± 5 and 32 ± 3 in two samples from Espegrend. Our assays included samples from mesocosm acidification experiments, but statistically significant effects of ocean acidification were not found by this method.

Impacts of acidification on macroinvertebrate communities in streams of the western Adirondack Mountains, New York, USA

USGS Publications Warehouse

Baldigo, Barry P.; Lawrence, G.B.; Bode, R.W.; Simonin, H.A.; Roy, K.M.; Smith, A.J.

2009-01-01

Limited stream chemistry and macroinvertebrate data indicate that acidic deposition has adversely affected benthic macroinvertebrate assemblages in numerous headwater streams of the western Adirondack Mountains of New York. No studies, however, have quantified the effects that acidic deposition and acidification may have had on resident fish and macroinvertebrate communities in streams of the region. As part of the Western Adirondack Stream Survey, water chemistry from 200 streams was sampled five times and macroinvertebrate communities were surveyed once from a subset of 36 streams in the Oswegatchie and Black River Basins during 2003-2005 and evaluated to: (a) document the effects that chronic and episodic acidification have on macroinvertebrate communities across the region, (b) define the relations between acidification and the health of affected species assemblages, and (c) assess indicators and thresholds of biological effects. Concentrations of inorganic Al in 66% of the 200 streams periodically reached concentrations toxic to acid-tolerant biota. A new acid biological assessment profile (acidBAP) index for macroinvertebrates, derived from percent mayfly richness and percent acid-tolerant taxa, was strongly correlated (R2 values range from 0.58 to 0.76) with concentrations of inorganic Al, pH, ANC, and base cation surplus (BCS). The BCS and acidBAP index helped remove confounding influences of natural organic acidity and to redefine acidification-effect thresholds and biological-impact categories. AcidBAP scores indicated that macroinvertebrate communities were moderately or severely impacted by acidification in 44-56% of 36 study streams, however, additional data from randomly selected streams is needed to accurately estimate the true percentage of streams in which macroinvertebrate communities are adversely affected in this, or other, regions. As biologically relevant measures of impacts caused by acidification, both BCS and acidBAP may be useful indicators of ecosystem effects and potential recovery at the local and regional scale.

Impacts of temperature increase and acidification on thickness of the surface mucopolysaccharide layer of the Caribbean coral Diploria spp.

NASA Astrophysics Data System (ADS)

Pratte, Zoe A.; Richardson, Laurie L.

2014-06-01

Coral mechanisms of resilience and resistance to stressors such as increasing sea surface temperature and ocean acidification must first be understood in order to facilitate the survival of coral reefs as we know them. One such mechanism is production of the protective surface mucopolysaccharide layer (SML). In this study, we investigated changes in the thickness of the SML in response to increasing temperature and acidification for the three Caribbean scleractinian coral species of the genus Diploria, which have been shown to exhibit differential resilience to disease and bleaching. Among the three species, Diploria strigosa is known to have a higher susceptibility to disease, Diploria labyrinthiformis is known to bleach more quickly, and Diploria clivosa is relatively unstudied. When temperature was increased from 25 to 31 °C over a 1- or 6-week period, the overall thickness of the SML decreased from 33 to 55 % for all three species. Average SML thickness at 25 °C for all three species ranged from 106 to 156 μm, while average thickness at 31 °C ranged from 64 to 86 μm. SML thickness was significantly different among species at 25 °C, but not at 31 °C. D. labyrinthiformis demonstrated lower fragment mortality due to thermal stress when compared to the other Diploria species. Acidification from pH 8.2 to 7.7 over 5 weeks had no effect on SML thickness for any species. The observed decrease in SML thickness in response to increased temperature might be attributed to a decrease in the production of mucus or an increase in the viscosity of the SML. These findings may help to explain the increased prevalence of coral disease during the warmer months, since increased temperature compromises an important aspect of coral innate immunity, as well as differences in disease and bleaching susceptibilities between Diploria species.

Effects of ocean acidification on the dissolution rates of reef-coral skeletons.

PubMed

van Woesik, Robert; van Woesik, Kelly; van Woesik, Liana; van Woesik, Sandra

2013-01-01

Ocean acidification threatens the foundation of tropical coral reefs. This study investigated three aspects of ocean acidification: (i) the rates at which perforate and imperforate coral-colony skeletons passively dissolve when pH is 7.8, which is predicted to occur globally by 2100, (ii) the rates of passive dissolution of corals with respect to coral-colony surface areas, and (iii) the comparative rates of a vertical reef-growth model, incorporating passive dissolution rates, and predicted sea-level rise. By 2100, when the ocean pH is expected to be 7.8, perforate Montipora coral skeletons will lose on average 15 kg CaCO3 m(-2) y(-1), which is approximately -10.5 mm of vertical reduction of reef framework per year. This rate of passive dissolution is higher than the average rate of reef growth over the last several millennia and suggests that reefs composed of perforate Montipora coral skeletons will have trouble keeping up with sea-level rise under ocean acidification. Reefs composed of primarily imperforate coral skeletons will not likely dissolve as rapidly, but our model shows they will also have trouble keeping up with sea-level rise by 2050.

Effects of cattle-slurry treatment by acidification and separation on nitrogen dynamics and global warming potential after surface application to an acidic soil.

PubMed

Fangueiro, David; Pereira, José; Bichana, André; Surgy, Sónia; Cabral, Fernanda; Coutinho, João

2015-10-01

Cattle-slurry (liquid manure) application to soil is a common practice to provide nutrients and organic matter for crop growth but it also strongly impacts the environment. The objective of the present study was to assess the efficiency of cattle-slurry treatment by solid-liquid separation and/or acidification on nitrogen dynamics and global warming potential (GWP) following application to an acidic soil. An aerobic laboratory incubation was performed over 92 days with a Dystric Cambisol amended with raw cattle-slurry or separated liquid fraction (LF) treated or not by acidification to pH 5.5 by addition of sulphuric acid. Soil mineral N contents and NH3, N2O, CH4 and CO2 emissions were measured. Results obtained suggest that the acidification of raw cattle-slurry reduced significantly NH3 emissions (-88%) but also the GWP (-28%) while increased the N availability relative to raw cattle-slurry (15% of organic N applied mineralised against negative mineralisation in raw slurry). However, similar NH3 emissions and GWP were observed in acidified LF and non-acidified LF treatments. On the other hand, soil application of acidified cattle-slurry rather than non-acidified LF should be preferred attending the lower costs associated to acidification compared to solid-liquid separation. It can then be concluded that cattle-slurry acidification is a solution to minimise NH3 emissions from amended soil and an efficient strategy to decrease the GWP associated with slurry application to soil. Furthermore, the more intense N mineralisation observed with acidified slurry should lead to a higher amount of plant available N and consequently to higher crop yields. Copyright © 2015 Elsevier Ltd. All rights reserved.

Integrating microbial fuel cells with anaerobic acidification and forward osmosis membrane for enhancing bio-electricity and water recovery from low-strength wastewater.

PubMed

Liu, Jinmeng; Wang, Xinhua; Wang, Zhiwei; Lu, Yuqin; Li, Xiufen; Ren, Yueping

2017-03-01

Microbial fuel cells (MFCs) and forward osmosis (FO) are two emerging technologies with great potential for energy-efficient wastewater treatment. In this study, anaerobic acidification and FO membrane were simultaneously integrated into an air-cathode MFC (AAFO-MFC) for enhancing bio-electricity and water recovery from low-strength wastewater. During a long-term operation of approximately 40 days, the AAFO-MFC system achieved a continuous and relatively stable power generation, and the maximum power density reached 4.38 W/m 3 . The higher bio-electricity production in the AAFO-MFC system was mainly due to the accumulation of ethanol resulted from anaerobic acidification process and the rejection of FO membrane. In addition, a proper salinity environment in the system controlled by the addition of MF membrane enhanced the electricity production. Furthermore, the AAFO-MFC system produced a high quality effluent, with the removal rates of organic matters and total phosphorus of more than 97%. However, the nitrogen removal was limited for the lower rejection of FO membrane. The combined biofouling and inorganic fouling were responsible for the lower water flux of FO membrane, and the Desulfuromonas sp. utilized the ethanol for bio-electricity production was observed in the anode. These results substantially improve the prospects for simultaneous wastewater treatment and energy recovery, and further studies are needed to optimize the system integration and operating parameters. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of stream acidification and habitat on fish populations of a North American river

USGS Publications Warehouse

Baldigo, Barry P.; Lawrence, G.B.

2001-01-01

Water quality, physical habitat, and fisheries at sixteen reaches in the Neversink River Basin were studied during 1991-95 to identify the effects of acidic precipitation on stream-water chemistry and on selected fish-species populations, and to test the hypothesis that the degree of stream acidification affected the spatial distribution of each fish-species population. Most sites on the East Branch Neversink were strongly to severely acidified, whereas most sites on the West Branch were minimally to moderately acidified. Mean density of fish populations ranged from 0 to 2.15 fish/m2; biomass ranged from 0 to 17.5 g/m2. Where brook trout were present, their population density ranged from 0.04 to 1.09 fish/m2, biomass ranged from 0.76 to 12.2 g/m2, and condition (K) ranged from 0.94 to 1.07. Regression analyses revealed strong relations (r2 ?? 0.41 to 0.99; p ??? 0.05) between characteristics of the two most common species (brook trout and slimy sculpin) populations and mean concentrations of inorganic monomeric aluminum (Alim), pH, Si, K+, NO3/-, NH4/+, DOC, Ca2+, and Na+; acid neutralizing capacity (ANC); and water temperature. Stream acidification may have adversely affected fish populations at most East Branch sites, but in other parts of the Neversink River Basin these effects were masked or mitigated by other physical habitat, geochemical, and biological factors.

Diatom diversity in chronically versus episodically acidified adirondack streams

USGS Publications Warehouse

Passy, S.I.; Ciugulea, I.; Lawrence, G.B.

2006-01-01

The relationship between algal species richness and diversity, and pH is controversial. Furthermore, it is still unknown how episodic stream acidification following atmospheric deposition affects species richness and diversity. Here we analyzed water chemistry and diatom epiphyton dynamics and showed their contrasting behavior in chronically vs. episodically acidic streams in the Adirondack region. Species richness and diversity were significantly higher in the chronically acidic brown water stream, where organic acidity was significantly higher and the ratio of inorganic to organic monomeric aluminum significantly lower. Conversely, in the episodically acidic clear water stream, the inorganic acidity and pH were significantly higher and the diatom communities were very species-poor. This suggests that episodic acidification in the Adirondacks may be more stressful for stream biota than chronic acidity. Strong negative linear relationships between species diversity, Eunotia exigua, and dissolved organic carbon against pH were revealed after the influence of non-linear temporal trends was partialled out using a novel way of temporal modeling. ?? 2006 WILEY-VCH Verlag GmbH & Co. KGaA.

Leaching of Heavy Metals from Water Bottle Components into the Drinking Water of Rodents

PubMed Central

Nunamaker, Elizabeth A; Otto, Kevin J; Artwohl, James E; Fortman, Jeffrey D

2013-01-01

Providing high-quality, uncontaminated drinking water is an essential component of rodent husbandry. Acidification of drinking water is a common technique to control microbial growth but is not a benign treatment. In addition to its potential biologic effects, acidified water might interact with the water-delivery system, leading to the leaching of heavy metals into the drinking water. The goal of the current study was to evaluate the effects of water acidification and autoclaving on water-bottle assemblies. The individual components of the system (stainless-steel sipper tubes, rubber stoppers, neoprene stoppers, and polysulfone water bottles) were acid-digested and analyzed for cadmium, chromium, copper, iron, lead, magnesium, manganese, selenium, and zinc to quantify the metal composition of each material. In addition the amounts of these metals that leached into tap and acidified water with and without autoclaving were quantified after 1 wk of contact time. On a weight basis, sipper tubes contained the largest quantities of all metals except magnesium and zinc, which were greatest in the neoprene stoppers. Except for cadmium and selenium, all metals had leached into the water after 1 wk, especially under the acidified condition. The quantities of copper, lead, and zinc that leached into the drinking water were the most noteworthy, because the resulting concentrations had the potential to confound animal experiments. On the basis of these findings, we suggest that water-quality monitoring programs include heavy metal analysis at the level of water delivery to animals. PMID:23562029

Leaching of heavy metals from water bottle components into the drinking water of rodents.

PubMed

Nunamaker, Elizabeth A; Otto, Kevin J; Artwohl, James E; Fortman, Jeffrey D

2013-01-01

Providing high-quality, uncontaminated drinking water is an essential component of rodent husbandry. Acidification of drinking water is a common technique to control microbial growth but is not a benign treatment. In addition to its potential biologic effects, acidified water might interact with the water-delivery system, leading to the leaching of heavy metals into the drinking water. The goal of the current study was to evaluate the effects of water acidification and autoclaving on water-bottle assemblies. The individual components of the system (stainless-steel sipper tubes, rubber stoppers, neoprene stoppers, and polysulfone water bottles) were acid-digested and analyzed for cadmium, chromium, copper, iron, lead, magnesium, manganese, selenium, and zinc to quantify the metal composition of each material. In addition the amounts of these metals that leached into tap and acidified water with and without autoclaving were quantified after 1 wk of contact time. On a weight basis, sipper tubes contained the largest quantities of all metals except magnesium and zinc, which were greatest in the neoprene stoppers. Except for cadmium and selenium, all metals had leached into the water after 1 wk, especially under the acidified condition. The quantities of copper, lead, and zinc that leached into the drinking water were the most noteworthy, because the resulting concentrations had the potential to confound animal experiments. On the basis of these findings, we suggest that water-quality monitoring programs include heavy metal analysis at the level of water delivery to animals.

Liming of acidified waters: issues and research - a report of the International Liming Workshop

USGS Publications Warehouse

Schreiber, R. Kent

1982-01-01

Acidic deposition is a problem of significant national and international concern. It is strongly suspected that acidic deposition has adversely affected aquatic resources in Scandinavia and North America. While substantial resources are being devoted to understanding the causative factors associated with surface water acidification, much less research is being conducted on mitigative strategies. Mitigative techniques involving liming may be useful for short-term protection of specific component of aquatic communities or for renovation of seriously impacted aquatic ecosystems. The selection of effective liming strategies is based on an integrated understanding of the following key factors: biological systems, water chemistry, sediment chemistry, hydrology, and watershed characteristics, effectiveness of neutralizing materials, and application techniques. Research in Scandinavia, Canada, and the U.S. has led to a partial understanding of some of the key factors for successful neutralization of surface waters (Bengtsson, 1982; Fraser and Britt, 1982). However, conflicting results of liming operations and experiments have been reported. (Fraser et al., 1982; Fraser and Britt, 1982; Sverdrup and Bjerle, 1982). Additional research is required to improve the ability of scientists and resource managers to select effective liming strategies. An International Liming workshop was convened during 19-25 September 1982 at the University of Washington's Friday Harbor Laboratories. The major objective of this workshop were: - To identify the most critical deficiencies in the scientific understanding of liming techniques and their long-term consequences. - To develop and document a research strategy to address information deficiencies that are pertinent to the protection or renovation of acidic surface waters in the United States. The participants who contributed to this workshop are listed in Table 1.

Ocean Acidification from space: recent advances

NASA Astrophysics Data System (ADS)

Sabia, Roberto; Shutler, Jamie; Land, Peter; Fernandez-Prieto, Diego; Donlon, Craig; Reul, Nicolas

2017-04-01

The phenomenon referred to as Ocean Acidification (OA) is gathering increasing attention as one of the major foci of climate-related research, for its profound impact at scientific and socio-economic level. To date, the majority of the scientific studies into the potential impacts of OA have focused on in-situ measurements, laboratory-controlled experiments and models simulations. Satellite remote sensing technology have yet to be fully exploited, despite it has been stressed it could play a significant role by providing synoptic and frequent measurements for investigating globally OA processes, also extending in-situ carbonate chemistry measurements on different spatial/temporal scales [1,2]. Within this context, the purpose of the recently completed ESA "Pathfinders - Ocean Acidification" project was to quantitatively and routinely estimate OA-related parameters by means of a blending of satellite observations and model outputs in five case-study regions (global ocean, Amazon plume, Barents sea, Greater Caribbean and Bay of Bengal). Satellite Ocean Colour, Sea Surface Temperature (SST) and Sea Surface Salinity (SSS) have been exploited, with an emphasis on the latter being the latest addition to the portfolio of satellite measured parameters. A proper merging of these different satellites products allows computing at least two independent proxies among the seawater carbonate system parameters: the partial pressure of CO2 in surface seawater (pCO2); the total Dissolved Inorganic Carbon (DIC), the total alkalinity (TA) and the surface ocean pH. In the project, efforts have been devoted to a systematic characterization of TA and DIC from space in the mentioned case-study regions; in this paper, also through the knowledge of these parameters, the objective is to come up with the currently best educated guess of the surface ocean pH [3] and Aragonite saturation state. This will also include an estimation of the achievable accuracy by propagating the errors in the satellite data sources. The overarching long-term objectives are to develop new algorithms and data processing strategies to overcome the relative immaturity of OA satellite products currently available, and to produce a global, temporally evolving, quasi-operational suite of OA satellite-derived data. References: [1] Land, P., J. Shutler, H. Findlay, F. Girard-Ardhuin, R. Sabia, N. Reul, J.-F. Piolle, B. Chapron, Y. Quilfen, J. Salisbury, D. Vandemark, R. Bellerby, and P. Bhadury, "Salinity from space unlocks satellite-based assessment of ocean acidification", Environmental Science & Technology, DOI: 10.1021/es504849s, Publication Date (Web): January 8, 2015 [2] Salisbury, J., D. Vandemark, B. Jönsson, W. Balch, S. Chakraborty, S. Lohrenz, B. Chapron, B. Hales, A. Mannino, J.T. Mathis, N. Reul, S.R. Signorini, R. Wanninkhof, and K.K. Yates. 2015. How can present and future satellite missions support scientific studies that address ocean acidification? Oceanography 28(2):108-121, http://dx.doi.org/10.5670/oceanog.2015.35. [3] Sabia R., D. Fernández-Prieto, J. Shutler, C. Donlon, P. Land, N. Reul, Remote Sensing of Surface Ocean pH Exploiting Sea Surface Salinity Satellite Observations, IGARSS '15 (International Geoscience and Remote Sensing Symposium), Milano, Italy, July 27 -31, 2015.

Ecological and toxicological effects of inorganic nitrogen pollution in aquatic ecosystems: A global assessment.

PubMed

Camargo, Julio A; Alonso, Alvaro

2006-08-01

We provide a global assessment, with detailed multi-scale data, of the ecological and toxicological effects generated by inorganic nitrogen pollution in aquatic ecosystems. Our synthesis of the published scientific literature shows three major environmental problems: (1) it can increase the concentration of hydrogen ions in freshwater ecosystems without much acid-neutralizing capacity, resulting in acidification of those systems; (2) it can stimulate or enhance the development, maintenance and proliferation of primary producers, resulting in eutrophication of aquatic ecosystems; (3) it can reach toxic levels that impair the ability of aquatic animals to survive, grow and reproduce. Inorganic nitrogen pollution of ground and surface waters can also induce adverse effects on human health and economy. Because reductions in SO2 emissions have reduced the atmospheric deposition of H2SO4 across large portions of North America and Europe, while emissions of NOx have gone unchecked, HNO3 is now playing an increasing role in the acidification of freshwater ecosystems. This acidification process has caused several adverse effects on primary and secondary producers, with significant biotic impoverishments, particularly concerning invertebrates and fishes, in many atmospherically acidified lakes and streams. The cultural eutrophication of freshwater, estuarine, and coastal marine ecosystems can cause ecological and toxicological effects that are either directly or indirectly related to the proliferation of primary producers. Extensive kills of both invertebrates and fishes are probably the most dramatic manifestation of hypoxia (or anoxia) in eutrophic and hypereutrophic aquatic ecosystems with low water turnover rates. The decline in dissolved oxygen concentrations can also promote the formation of reduced compounds, such as hydrogen sulphide, resulting in higher adverse (toxic) effects on aquatic animals. Additionally, the occurrence of toxic algae can significantly contribute to the extensive kills of aquatic animals. Cyanobacteria, dinoflagellates and diatoms appear to be major responsible that may be stimulated by inorganic nitrogen pollution. Among the different inorganic nitrogenous compounds (NH4+, NH3, NO2-, HNO2NO3-) that aquatic animals can take up directly from the ambient water, unionized ammonia is the most toxic, while ammonium and nitrate ions are the least toxic. In general, seawater animals seem to be more tolerant to the toxicity of inorganic nitrogenous compounds than freshwater animals, probably because of the ameliorating effect of water salinity (sodium, chloride, calcium and other ions) on the tolerance of aquatic animals. Ingested nitrites and nitrates from polluted drinking waters can induce methemoglobinemia in humans, particularly in young infants, by blocking the oxygen-carrying capacity of hemoglobin. Ingested nitrites and nitrates also have a potential role in developing cancers of the digestive tract through their contribution to the formation of nitrosamines. In addition, some scientific evidences suggest that ingested nitrites and nitrates might result in mutagenicity, teratogenicity and birth defects, contribute to the risks of non-Hodgkin's lymphoma and bladder and ovarian cancers, play a role in the etiology of insulin-dependent diabetes mellitus and in the development of thyroid hypertrophy, or cause spontaneous abortions and respiratory tract infections. Indirect health hazards can occur as a consequence of algal toxins, causing nausea, vomiting, diarrhoea, pneumonia, gastroenteritis, hepatoenteritis, muscular cramps, and several poisoning syndromes (paralytic shellfish poisoning, neurotoxic shellfish poisoning, amnesic shellfish poisoning). Other indirect health hazards can also come from the potential relationship between inorganic nitrogen pollution and human infectious diseases (malaria, cholera). Human sickness and death, extensive kills of aquatic animals, and other negative effects, can have elevated costs on human economy, with the recreation and tourism industry suffering the most important economic impacts, at least locally. It is concluded that levels of total nitrogen lower than 0.5-1.0 mg TN/L could prevent aquatic ecosystems (excluding those ecosystems with naturally high N levels) from developing acidification and eutrophication, at least by inorganic nitrogen pollution. Those relatively low TN levels could also protect aquatic animals against the toxicity of inorganic nitrogenous compounds since, in the absence of eutrophication, surface waters usually present relatively high concentrations of dissolved oxygen, most inorganic reactive nitrogen being in the form of nitrate. Additionally, human health and economy would be safer from the adverse effects of inorganic nitrogen pollution.

Quantifying Organic Matter in Surface Waters of the United States and Delivery to the Coastal Zone

NASA Astrophysics Data System (ADS)

Boyer, E. W.; Alexander, R. B.; Smith, R. A.; Shih, J.

2012-12-01

Organic carbon (OC) is a critical water quality characteristic in surface waters. It is an important component of the energy balance and food chains in freshwater and estuarine aquatic ecosystems, is significant in the mobilization and transport of contaminants along flow paths, and is associated with the formation of known carcinogens in drinking water supplies. The importance of OC dynamics on water quality has been recognized, but challenges remain in quantitatively addressing processes controlling OC fluxes over broad spatial scales in a hydrological context, and considering upstream-downstream linkages along flow paths. Here, we: 1) quantified lateral OC fluxes in rivers, streams, and reservoirs across the nation from headwaters to the coasts; 2) partitioned how much organic carbon that is stored in lakes, rivers and streams comes from allochthonous sources (produced in the terrestrial landscape) versus autochthonous sources (produced in-stream by primary production); 3) estimated the delivery of dissolved and total forms of organic carbon to coastal estuaries and embayments; and 4) considered seasonal factors affecting the temporal variation in OC responses. To accomplish this, we developed national-scale models of organic carbon in U.S. surface waters using the spatially referenced regression on watersheds (SPARROW) technique. The modeling approach uses mechanistic formulations, imposes mass balance constraints, and provides a formal parameter estimation structure to statistically estimate sources and fate of OC in terrestrial and aquatic ecosystems. We calibrated and evaluated the model with statistical estimates of OC loads that were observed at a network of monitoring stations across the nation, and further explored factors controlling seasonal dynamics of OC based on these long term monitoring data. Our results illustrate spatial patterns and magnitudes OC loadings in rivers, highlighting hot spots and suggesting origins of the OC to each location. Further, our results yield quantitative estimates of aquatic OC fluxes for large water regions and for the nation, providing a refined estimate of the role of surface water fluxes of OC in relationship to regional and national carbon budgets. Finally, we are using our simulations to explore the role of OC in relation to other nutrients in contributing to acidification and eutrophication of coastal waters.

Calcification in Caribbean reef-building corals at high pCO2 levels in a recirculating ocean acidification exposure system.

PubMed

Enzor, Laura A; Hankins, Cheryl; Vivian, Deborah N; Fisher, William S; Barron, Mace G

2018-02-01

Projected increases in ocean p CO 2 levels are anticipated to affect calcifying organisms more rapidly and to a greater extent than other marine organisms. The effects of ocean acidification (OA) have been documented in numerous species of corals in laboratory studies, largely tested using flow-through exposure systems. We developed a recirculating ocean acidification exposure system that allows precise p CO 2 control using a combination of off-gassing measures including aeration, water retention devices, venturi injectors, and CO 2 scrubbing. We evaluated the recirculating system performance in off-gassing effectiveness and maintenance of target p CO 2 levels over an 84-day experiment. The system was used to identify changes in calcification and tissue growth in response to elevated p CO 2 (1000 μatm) in three reef-building corals of the Caribbean: Pseudodiploria clivosa , Montastraea cavernosa , and Orbicella faveolata . All three species displayed an overall increase in net calcification over the 84-day exposure period regardless of p CO 2 level (control +0.28- 1.12 g, elevated p CO 2 +0.18- 1.16 g), and the system was effective at both off-gassing acidified water to ambient p CO 2 levels, and maintaining target elevated p CO 2 levels over the 3-month experiment.

Carbonate system variability in the Gulf of Trieste (North Adriatic Sea)

NASA Astrophysics Data System (ADS)

Cantoni, Carolina; Luchetta, Anna; Celio, Massimo; Cozzi, Stefano; Raicich, Fabio; Catalano, Giulio

2012-12-01

The seasonal variability of the carbonate system in the waters of the Gulf of Trieste (GoT) was studied at PALOMA station from 2008 to 2009, in order to highlight the effects of biological processes, meteorological forcings and river loads on the dynamics of pHT, CO2 partial pressure (pCO2), dissolved inorganic carbon (DIC), carbonate ion concentration (CO3=), aragonite saturation state (ΩAr) and total alkalinity (AT). During winter, low seawater temperature (9.0 ± 0.4 °C) and a weak biological activity (-10.7 < AOU < 15.7 μmol O2 kg-1) in a homogeneous water column led to the lowest average values of pCO2 (328 ± 19 μatm) and ΩAr (2.91 ± 0.14). In summer, the water column in the area acted as a two-layer system, with production processes prevailing in the upper layer (average AOU = -29.3 μmol O2 kg-1) and respiration processes in the lower layer (average AOU = 26.8 μmol O2 kg-1). These conditions caused the decrease of DIC (50 μmol kg-1) and the increase of ΩAr (1.0) values in the upper layer, whereas opposite trends were observed in the bottom waters. In August 2008, during a hypoxic event (dissolved oxygen DO = 86.9 μmol O2 kg-1), the intense remineralisation of organic carbon caused the rise of pCO2 (1043 μatm) and the decreases of pHT and ΩAr values down to 7.732 and 1.79 respectively. On an annual basis, surface pCO2 was mainly regulated by the pronounced seasonal cycle of seawater temperature. In winter, surface waters in the GoT were under-saturated with respect to atmospheric CO2, thus acting as a sink of CO2, in particular when strong-wind events enhanced air-sea gas exchange (FCO2 up to -11.9 mmol m-2 d-1). During summer, the temperature-driven increase of pCO2 was dampened by biological CO2 uptake, as consequence a slight over-saturation (pCO2 = 409 μatm) turned out. River plumes were generally associated to higher AT and pCO2 values (up to 2859 μmol kg-1 and 606 μatm respectively), but their effect was highly variable in space and time. During winter, the ambient conditions that favour the formation of dense waters on this continental shelf, also favour a high absorption of CO2 in seawater and its consequent acidification (pHT decrease of -0.006 units during a 7-day Bora wind event). This finding indicates a high vulnerability of North Adriatic Dense Water to atmospheric CO2 increase and ocean acidification process.

40 CFR 141.86 - Monitoring requirements for lead and copper in tap water.

Code of Federal Regulations, 2011 CFR

2011-07-01

... procedures specified in this paragraph. To avoid problems of residents handling nitric acid, acidification of... no plastic pipes which contain lead plasticizers, or plastic service lines which contain lead...

40 CFR 141.86 - Monitoring requirements for lead and copper in tap water.

Code of Federal Regulations, 2010 CFR

2010-07-01

... procedures specified in this paragraph. To avoid problems of residents handling nitric acid, acidification of... no plastic pipes which contain lead plasticizers, or plastic service lines which contain lead...

Short-term metabolic and growth responses of the cold-water coral Lophelia pertusa to ocean acidification

NASA Astrophysics Data System (ADS)

Hennige, S. J.; Wicks, L. C.; Kamenos, N. A.; Bakker, D. C. E.; Findlay, H. S.; Dumousseaud, C.; Roberts, J. M.

2014-01-01

Cold-water corals are associated with high local biodiversity, but despite their importance as ecosystem engineers, little is known about how these organisms will respond to projected ocean acidification. Since preindustrial times, average ocean pH has decreased from 8.2 to ~8.1, and predicted CO2 emissions will decrease by up to another 0.3 pH units by the end of the century. This decrease in pH may have a wide range of impacts upon marine life, and in particular upon calcifiers such as cold-water corals. Lophelia pertusa is the most widespread cold-water coral (CWC) species, frequently found in the North Atlantic. Here, we present the first short-term (21 days) data on the effects of increased CO2 (750 ppm) upon the metabolism of freshly collected L. pertusa from Mingulay Reef Complex, Scotland, for comparison with net calcification. Over 21 days, corals exposed to increased CO2 conditions had significantly lower respiration rates (11.4±1.39 SE, μmol O2 g-1 tissue dry weight h-1) than corals in control conditions (28.6±7.30 SE μmol O2 g-1 tissue dry weight h-1). There was no corresponding change in calcification rates between treatments, measured using the alkalinity anomaly technique and 14C uptake. The decrease in respiration rate and maintenance of calcification rate indicates an energetic imbalance, likely facilitated by utilisation of lipid reserves. These data from freshly collected L. pertusa from the Mingulay Reef Complex will help define the impact of ocean acidification upon the growth, physiology and structural integrity of this key reef framework forming species.

Sources of Nutrients to Nearshore Areas of a Eutrophic Estuary: Implications for Nutrient-Enhanced Acidification in Puget Sound

NASA Astrophysics Data System (ADS)

Pacella, S. R.

2016-02-01

Ocean acidification has recently been highlighted as a major stressor for coastal organisms. Further work is needed to assess the role of anthropogenic nutrient additions in eutrophied systems on local biological processes, and how this interacts with CO2 emission-driven acidification. This study sought to distinguish changes in pH caused by natural versus anthropogenically affected processes. We quantified the variability in water column pH attributable to primary production and respiration fueled by anthropogenically derived nitrogen in a shallow nearshore area. Two study sites were located in shallow subtidal areas of the Snohomish River estuary, a eutrophic system located in central Puget Sound, Washington. These sites were chosen due to the presence of heavy agricultural activity, urbanized areas with associated waste water treatment, as well as influence from deep, high CO2 marine waters transported through the Strait of Juan de Fuca and upwelled into the area during spring and summer. Data was collected from July-December 2015 utilizing continuous moorings and discrete water column sampling. Analysis of stable isotopes, δ15N, δ18O-NO3, δ15N-NH4, was used to estimate the relative contributions of anthropogenic versus upwelled marine nitrogen sources. Continuous monitoring of pH, dissolved oxygen, temperature, and salinity was conducted at both study sites to link changes in nutrient source and availability with changes in pH. We predicted that isotope data would indicate greater contributions of nitrogen from agriculture and wastewater rather than upwelling in the shallow, nearshore study sites. This study seeks to distinguish the relative magnitude of pH change stimulated by anthropogenic versus natural sources of nitrogen to inform public policy decisions in critically important nearshore ecosystems.

Environmental mimics and the Lvh type IVA secretion system contribute to virulence-related phenotypes of Legionella pneumophila.

PubMed

Bandyopadhyay, Purnima; Liu, Shuqing; Gabbai, Carolina B; Venitelli, Zeah; Steinman, Howard M

2007-02-01

Legionella pneumophila, the causative organism of Legionnaires' disease, is a fresh-water bacterium and intracellular parasite of amoebae. This study examined the effects of incubation in water and amoeba encystment on L. pneumophila strain JR32 and null mutants in dot/icm genes encoding a type IVB secretion system required for entry, delayed acidification of L. pneumophila-containing phagosomes, and intracellular multiplication when stationary-phase bacteria infect amoebae and macrophages. Following incubation of stationary-phase cultures in water, mutants in dotA and dotB, essential for function of the type IVB secretion system, exhibited entry and delay of phagosome acidification comparable to that of strain JR32. Following encystment in Acanthamoeba castellanii and reversion of cysts to amoeba trophozoites, dotA and dotB mutants exhibited intracellular multiplication in amoebae. The L. pneumophila Lvh locus, encoding a type IVA secretion system homologous to that in Agrobacterium tumefaciens, was required for restoration of entry and intracellular multiplication in dot/icm mutants following incubation in water and amoeba encystment and was required for delay of phagosome acidification in strain JR32. These data support a model in which the Dot/Icm type IVB secretion system is conditionally rather than absolutely required for L. pneumophila virulence-related phenotypes. The data suggest that the Lvh type IVA secretion system, previously thought to be dispensable, is involved in virulence-related phenotypes under conditions mimicking the spread of Legionnaires' disease from environmental niches. Since environmental amoebae are implicated as reservoirs for an increasing number of environmental pathogens and for drug-resistant bacteria, the environmental mimics developed here may be useful in virulence studies of other pathogens.

Soil acidification as a confounding factor on metal phytotoxicity in soils spiked with copper-rich mine wastes.

PubMed

Ginocchio, Rosanna; De la Fuente, Luz María; Sánchez, Pablo; Bustamante, Elena; Silva, Yasna; Urrestarazu, Paola; Rodríguez, Patricio H

2009-10-01

Pollution of soil with mine wastes results in both Cu enrichment and soil acidification. This confounding effect may be very important in terms of phytotoxicity, because pH is a key parameter influencing Cu solubility in soil solution. Laboratory toxicity tests were used to assess the effect of acidification by acidic mine wastes on Cu solubility and on root elongation of barley (Hordeum vulgare L.). Three contrasting substrates (two soils and a commercial sand) and two acidic, Cu-rich mine wastes (oxidized tailings [OxT] and smelter dust [SmD]) were selected as experimental materials. Substrates were spiked with a fixed amount of either SmD or OxT, and the pH of experimental mixtures was then modified in the range of 4.0 to 6.0 and 7.0 using PIPES (piperazine-1,4-bis(2-ethanesulfonic acid)), MES (2-(N-morpholino)ethanesulfonic acid), and MOPS (3-(N-Morpholino)-propanesulfonic acid) buffers. Chemical (pore-water Cu and pH) and toxicological (root length of barley plants) parameters were determined for experimental mixtures. Addition of SmD and OxT to substrates resulted in acidification (0.11-1.16 pH units) and high levels of soluble Cu and Zn. Neutralization of experimental mixtures with MES (pH 6.0) and MOPS (pH 7.0) buffers resulted in a marked decrease in soluble Cu and Zn, but the intensity of the effect was substrate-dependent. Adjustment of soil pH above the range normally considered to be toxic to plants (pH in water extract, > 5.5) significantly reduced metal toxicity in barley, but phytotoxicity was not completely eliminated. The present results stress the importance of considering confounding effects on derivation of toxicity thresholds to plants when using laboratory phytotoxicity tests.

Behavioral Response of Hermit Crabs (Clibanarius digueti) to Dissolved Carbon Dioxide

NASA Astrophysics Data System (ADS)

Maier, H. J.

2016-02-01

CO2 induced ocean acidification is currently changing the population dynamics of marine organisms. This can involve increased stress in populations, and alteration in individual physiology, which can eventually be expressed through an organism's behavior. If sustained, CO2 induced ocean acidification has the potential to cause major impacts on marine food chains, including on services they provide. The purpose of this study was to understand whether and how ocean acidification affects the behavior of hermit crab Clibanarius digueti, a crustacean inhabiting the littoral zone. We hypothesized that an increase in dissolved carbonic acid would modify grazing and individual movement, because an increase in acidification alters the normal chemical composition of the water and potentially the physiology of C. digueti. A model tidal pool experiment consisting of two tanks (control and treatment) inhabited with seven living C. digueti was set up in the Ocean Biome of Biosphere-2. Each tank was also provided with uninhabited shells: two Turbo fluctuosa and four Cerithium sp. Gaseous CO2 was dissolved into the treatment tank and measured as dissolved CO2 by using a NaOH titration method. Additionally, water conditions were characterized for light and temperature. Two trials were run in this experiment with tanks and treatments interchanged in each trial. We found a marked treatment effect on C. digueti behavior. The population experiencing increased CO2 performed daily shell changes after first day of exposure for each of the 4-day trials, as compared to individuals unexposed to dissolved CO2, that experienced no shell changes. From this study we conclude that the behavior of C. Digueti can be a good indicator of changes in dissolved CO2. This would allow us to better interpret patterns in marine animal behavior in response to climate change.

Food availability and pCO2 impacts on planulation, juvenile survival, and calcification of the azooxanthellate scleractinian coral, Balanophyllia elegans

NASA Astrophysics Data System (ADS)

Crook, E. D.; Cooper, H.; Potts, D. C.; Lambert, T.; Paytan, A.

2013-05-01

Ocean acidification, the assimilation of atmospheric CO2 by the oceans that decreases the pH and CaCO3 saturation state (Ω) of seawater, is projected to have severe consequences for calcifying organisms. Strong evidence suggests that tropical reef-building corals containing algal symbionts (zooxanthellae) will experience dramatic declines in calcification over the next century. The responses of azooxanthellate corals to ocean acidification are less well understood, and because they cannot obtain extra photosynthetic energy from symbionts, they provide a system for studying the direct effects of acidification on the energy available for calcification. The orange cup coral Balanophyllia elegans is a solitary, azooxanthellate scleractinian species common on the California coast where it thrives in the low pH waters of an upwelling regime. During an 8 month study, we addressed the effects of three pCO2 treatments (410, 770, and 1230 μatm) and two feeding frequencies (High Food and Low Food) on adult Balanophyllia elegans planulation (larval release) rates, and on the survival, growth, and calcification of their juvenile offspring. Planulation rates were affected by food level but not pCO2, while juvenile survival was highest under 410 μatm and High Food conditions. Our results suggest that feeding rate has a greater impact on calcification of B. elegans than pCO2. Net calcification was positive even at 1230 μatm (~ 3 times current atmospheric pCO2), although the increase from 410 to 1230 μatm reduced overall calcification by ~ 25-45%, and reduced skeletal density by ~ 35-45%. Higher pCO2 also altered aragonite crystal morphology significantly. We discuss how feeding frequency affects azooxanthellate coral calcification, and how B. elegans may respond to ocean acidification in coastal upwelling waters.

75 FR 13537 - Clean Water Act Section 303(d): Notice of Call for Public Comment on 303(d) Program and Ocean...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-03-22

...), Joint Subcommittee on Ocean Science and Technology (JSOST), National Research Council report on Marine p... ideas for effective strategies for Federal, State, and local officials to use to address the potential... particularly suited to gathering information about acidification of ocean waters? ii. Are there new programs...

Effects of ocean acidification on single and mixed seagrass species meadows in estuarine waters of the Northern Gulf of Mexico

EPA Science Inventory

In an outdoor mesocosm, we tested the hypothesis that OA would benefit seagrasses in mesohaline waters of the Northern Gulf of Mexico in homo- and hetero- specific seagrass beds of Halodule wrightii and Ruppia maritima. In this estuarine environment, short-term increases in CO2 ...

Effects of acidification on bryophyte communities in West Virginia mountain streams

Treesearch

Steven L. Stephenson; Susan Moyle Studlar; Carolyn J. McQuattie; Pamela J. Edwards

1995-01-01

Bryophytes (mosses and liverworts) are often more responsive to water chemistry changes than are vascular plants. In this study, the relationships of bryophyte communities to stream pH and water chemistry were studied, using six streams on or near the Fernow Experimental Forest in Tucker County, West Virginia. Streams were surveyed with line transects using stratified...

Depth matters: Soil pH and dilution effects in the northern Great Plains

USDA-ARS?s Scientific Manuscript database

In the northern Great Plans (NGP), surface sampling depths of 0-15.2 cm or 0-20.3 cm are suggested for testing soil characteristics such as pH. However, acidification is often most pronounced near-surface (e.g., <10 cm). Thus, sampling deeper can potentially dilute (increase) pH measurements and the...

Prediction of episodic acidification in North-eastern USA: An empirical/mechanistic approach

USGS Publications Warehouse

Davies, T.D.; Tranter, M.; Wigington, P.J.; Eshleman, K.N.; Peters, N.E.; Van Sickle, J.; DeWalle, David R.; Murdoch, Peter S.

1999-01-01

Observations from the US Environmental Protection Agency's Episodic Response Project (ERP) in the North-eastern United States are used to develop an empirical/mechanistic scheme for prediction of the minimum values of acid neutralizing capacity (ANC) during episodes. An acidification episode is defined as a hydrological event during which ANC decreases. The pre-episode ANC is used to index the antecedent condition, and the stream flow increase reflects how much the relative contributions of sources of waters change during the episode. As much as 92% of the total variation in the minimum ANC in individual catchments can be explained (with levels of explanation >70% for nine of the 13 streams) by a multiple linear regression model that includes pre-episode ANC and change in discharge as independent variable. The predictive scheme is demonstrated to be regionally robust, with the regional variance explained ranging from 77 to 83%. The scheme is not successful for each ERP stream, and reasons are suggested for the individual failures. The potential for applying the predictive scheme to other watersheds is demonstrated by testing the model with data from the Panola Mountain Research Watershed in the South-eastern United States, where the variance explained by the model was 74%. The model can also be utilized to assess 'chemically new' and 'chemically old' water sources during acidification episodes.Observations from the US Environmental Protection Agency's Episodic Response Project (ERP) in the Northeastern United States are used to develop an empirical/mechanistic scheme for prediction of the minimum values of acid neutralizing capacity (ANC) during episodes. An acidification episode is defined as a hydrological event during which ANC decreases. The pre-episode ANC is used to index the antecedent condition, and the stream flow increase reflects how much the relative contributions of sources of waters change during the episode. As much as 92% of the total variation in the minimum ANC in individual catchments can be explained (with levels of explanation >70% for nine of the 13 streams) by a multiple linear regression model that includes pre-episode ANC and change in discharge as independent variables. The predictive scheme is demonstrated to be regionally robust, with the regional variance explained ranging from 77 to 83%. The scheme is not successful for each ERP stream, and reasons are suggested for the individual failures. The potential for applying the predictive scheme to other watersheds is demonstrated by testing the model with data from the Panola Mountain Research Watershed in the South-eastern United States, where the variance explained by the model was 74%. The model can also be utilized to assess `chemically new' and `chemically old' water sources during acidification episodes.

Recovery from chronic and snowmelt acidification: Long-term trends in stream and soil water chemistry at the Hubbard Brook Experimental Forest, New Hampshire, USA

Treesearch

Colin B. Fuss; Charles T. Driscoll; John L. Campbell

2015-01-01

Atmospheric acid deposition of sulfate and nitrate has declined markedly in the northeastern United States due to emissions controls. We investigated long-term trends in soil water (1984–2011) and stream water (1982–2011) chemistry along an elevation gradient of a forested watershed to evaluate the progress of recovery of drainage waters from acidic deposition at the...

Method development for the analysis of organophosphate and pyrethroid insecticides at low parts per trillion levels in water.

PubMed

Wang, Dongli; Weston, Donald P; Lydy, Michael J

2009-06-15

In the current study, organophosphate and pyrethroid insecticides including diazinon, chlorpyrifos, bifenthrin, fenpropathrin, permethrin, lambda-cyhalothrin, cyfluthrin, cypermethrin, esfenvalerate and deltamethrin were analyzed in laboratory and field-collected water samples. Water samples were extracted and analyzed by gas chromatography/electron capture detector (GC/ECD) and gas chromatography/nitrogen-phosphorous detector (GC/NPD). Comparison of results from liquid-liquid extraction and subsequent normal phase solid-phase extraction cleanup (LLE-NPSPE), and reversed phase solid-phase extraction (RPSPE) showed that LLE-NPSPE was the better choice to extract trace amounts of pesticides from water. Pesticide recoveries from four spiked water samples using LLE-NPSPE ranged from 63.2 to 148.8% at four spiking concentrations. Method detection limits were 0.72-1.69 ng/L using four different water sources. The stability of the target pesticides in lake water was investigated at 4 degrees C for 1h, 1d, 4d, and 7d under three conditions: (1) water samples only; (2) with 20 mL hexane used as a keeper solvent; and (3) with acidification to pH 2 with HCl. Results showed that water storage without treatment resulted in slow degradation of some pesticides with storage time, storage using water acidification led to significant degradation and loss of diazinon and chlorpyrifos, while water storage with hexane as a keeper solvent showed good stability for all of the target pesticides over the 7d storage period.

Climate conditions, and changes, affect microalgae communities… should we worry?

PubMed

Gimenez Papiol, Gemma

2018-03-01

Microalgae play a pivotal role in the regulation of Earth's climate and its cycles, but are also affected by climate change, mainly by changes in temperature, light, ocean acidification, water stratification, and precipitation-induced nutrient inputs. The changes and impacts on microalgae communities are difficult to study, predict, and manage, but there is no doubt that there will be changes. These changes will have impacts beyond microalgae communities, and many of them will be negative. Some actions are currently ongoing for the mitigation of some of the negative impacts, such as harmful algal blooms and water quality, but global efforts for reducing CO 2 emissions, temperature rises, and ocean acidification are paramount for reducing the impact of climate change on microalgae communities, and eventually, on human well-being. Integr Environ Assess Manag 2018;14:181-184. © 2018 SETAC. © 2018 SETAC.

Natural ocean acidification at Papagayo upwelling system (north Pacific Costa Rica): implications for reef development

NASA Astrophysics Data System (ADS)

Sánchez-Noguera, Celeste; Stuhldreier, Ines; Cortés, Jorge; Jiménez, Carlos; Morales, Álvaro; Wild, Christian; Rixen, Tim

2018-04-01

Numerous experiments have shown that ocean acidification impedes coral calcification, but knowledge about in situ reef ecosystem response to ocean acidification is still scarce. Bahía Culebra, situated at the northern Pacific coast of Costa Rica, is a location naturally exposed to acidic conditions due to the Papagayo seasonal upwelling. We measured pH and pCO2 in situ during two non-upwelling seasons (June 2012, May-June 2013), with a high temporal resolution of every 15 and 30 min, respectively, using two Submersible Autonomous Moored Instruments (SAMI-pH, SAMI-CO2). These results were compared with published data from the 2009 upwelling season. Findings revealed that the carbonate system in Bahía Culebra shows a high temporal variability. Incoming offshore waters drive intra- and interseasonal changes. Lowest pH (7.8) and highest pCO2 (658.3 µatm) values measured during a cold-water intrusion event in the non-upwelling season were similar to those minimum values reported from upwelling season (pH = 7.8, pCO2 = 643.5 µatm), unveiling that natural acidification also occurs sporadically in the non-upwelling season. This affects the interaction of photosynthesis, respiration, calcification and carbonate dissolution and the resulting diel cycle of pH and pCO2 in the reefs of Bahía Culebra. During the non-upwelling season, the aragonite saturation state (Ωa) rises to values of > 3.3 and during the upwelling season falls below 2.5. The Ωa threshold values for coral growth were derived from the correlation between measured Ωa and coral linear extension rates which were obtained from the literature and suggest that future ocean acidification will threaten the continued growth of reefs in Bahía Culebra. These data contribute to building a better understanding of the carbonate system dynamics and coral reefs' key response (e.g., coral growth) to natural low-pH conditions, in upwelling areas in the eastern tropical Pacific and beyond.

Trends in nutrients

USGS Publications Warehouse

Heathwaite, A.L.; Johnes, P.J.; Peters, N.E.

1996-01-01

The roles of nitrogen (N) and phosphorus (P) as key nutrients determining the trophic status of water bodies are examined, and evidence reviewed for trends in concentrations of N and P species which occur in freshwaters, primarily in northern temperate environments. Data are reported for water bodies undergoing eutrophication and acidification, especially water bodies receiving increased nitrogen inputs through the atmospheric deposition of nitrogen oxides (NOx). Nutrient loading on groundwaters and surface freshwaters is assessed with respect to causes and rates of (change, relative rates of change for N and P, and implications of change for the future management of lakes, rivers and groundwaters. In particular, the nature and emphasis of studies for N species and P fractions in lakes versus rivers and groundwaters are contrasted. This review paper primarily focuses on results from North America and Europe, particularly for the UK where a wide range of data sets exists. Few nutrient loading data have been published on water bodies in less developed countries; however, some of the available data are presented to provide a global perspective. In general, N and P concentrations have increased dramatically (>20 times background concentrations) in many areas and causes vary considerably, ranging from urbanization to changes in agricultural practices.

Red herring in acid rain research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Havas, M.; Hutchinson, T.C.; Likens, G.E.

1984-06-01

Five common misconceptions, red herrings, regarding the effects of acid deposition on aquatic ecosystems are described in an attempt to clarify some of the confusion they have created. These misconceptions are the following: Bog lakes have been acidic for thousands of years; thus the acidification of lakes is not a recent phenomenon. The early methods for measuring pH are in error; therfore, no statements can be made regarding historical trends. Acidification of lakes and streams results from changed land use practices (forestry, agriculture, animal husbandry) and not acid deposition. The decrease in fish populations is caused by overfishing, disease, andmore » water pollution, not acidification. Because lakes that receive identical rainfall can have considerable different pHs, regional lake acidification cannot be due to acid precipitation. It is easy to suggest a whole series of alternative, and often unlikely, explanations of the causes and consequences of acid deposition. These keep scientists busy for years assembling and examining data only to conclude that the explanation is not valid. These tactics cause, and perhaps are designed to cause, continuous delay in remedial action. They fail to take into account the large body of information that deals with the sources of the acid deposition and the seriousness of its effects.« less

Symbiosis increases coral tolerance to ocean acidification

NASA Astrophysics Data System (ADS)

Ohki, S.; Irie, T.; Inoue, M.; Shinmen, K.; Kawahata, H.; Nakamura, T.; Kato, A.; Nojiri, Y.; Suzuki, A.; Sakai, K.; van Woesik, R.

2013-04-01

Increasing the acidity of ocean waters will directly threaten calcifying marine organisms such as reef-building scleractinian corals, and the myriad of species that rely on corals for protection and sustenance. Ocean pH has already decreased by around 0.1 pH units since the beginning of the industrial revolution, and is expected to decrease by another 0.2-0.4 pH units by 2100. This study mimicked the pre-industrial, present, and near-future levels of pCO2 using a precise control system (±5% pCO2), to assess the impact of ocean acidification on the calcification of recently-settled primary polyps of Acropora digitifera, both with and without symbionts, and adult fragments with symbionts. The increase in pCO2 of 100 μatm between the pre-industrial period and the present had more effect on the calcification rate of adult A. digitifera than the anticipated future increases of several hundreds of micro-atmospheres of pCO2. The primary polyps with symbionts showed higher calcification rates than primary polyps without symbionts, suggesting that (i) primary polyps housing symbionts are more tolerant to near-future ocean acidification than organisms without symbionts, and (ii) corals acquiring symbionts from the environment (i.e. broadcasting species) will be more vulnerable to ocean acidification than corals that maternally acquire symbionts.

Citric-acid preacidification enhanced electrokinetic remediation for removal of chromium from chromium-residue-contaminated soil.

PubMed

Meng, Fansheng; Xue, Hao; Wang, Yeyao; Zheng, Binghui; Wang, Juling

2018-02-01

Electrokinetic experiments were conducted on chromium-residue-contaminated soils collected from a chemical plant in China. Acidification-electrokinetic remediation technology was proposed in order to solve the problem of removing inefficient with ordinary electrokinetic. The results showed that electrokinetic remediation removal efficiency of chromium from chromium-contaminated soil was significantly enhanced with acidizing pretreatment. The total chromium [Cr(T)] and hexavalent chromium [Cr(VI)] removal rate of the group acidized by citric acid (0.9 mol/L) for 5 days was increased from 6.23% and 19.01% in the acid-free experiments to 26.97% and 77.66% in the acidification-treated experiments, respectively. In addition, part of chromium with the state of carbonate-combined will be converted into water-soluble state through acidification to improve the removal efficiency. Within the appropriate concentration range, the higher concentration of acid was, the more chromium was released. So the removal efficiency of chromium depended on the acid concentration. The citric acid is also a kind of complexing agent, which produced complexation with Cr that was released by the electrokinetic treatment and then enhanced the removal efficiency. The major speciation of chromium that was removed from soils by acidification-electrokinetics remediation was acid-soluble speciation, revivification speciation and oxidation speciation, which reduced biological availability of chromium.

Effects of acidification on metal availability to aquatic biota, with special reference to filamentous algae.

PubMed

Stokes, P M; Bailey, R C; Groulx, G R

1985-11-01

A survey of 34 shield lakes in Ontario and Quebec, pH 4.4 to 7.1, was made to evaluate which metals should be considered of concern as a risk to aquatic biota or consumers when lakes are acid stressed. A set of predictions, concerning the mobilization by man, the mobility, the chemical speciation, and the toxicity or bioaccumulation of metals in acid-stressed waters, were used as a basis for designing the study and organizing the results. Attached algae were used as biomonitors to assess metal bioavailability. The study concluded that zinc, lead, aluminum, and mercury were of concern in acid-stressed lakes, while the situation for manganese was unresolved, and cadmium was not studied. Nickel and copper were of concern only when a point source was involved. The study also concluded that the attached algal community had some value as a biomonitor, for metals in acid-stressed as well as metal-polluted surface waters.

Effects of acidification on metal availability to aquatic biota, with special reference to filamentous algae.

PubMed Central

Stokes, P M; Bailey, R C; Groulx, G R

1985-01-01

A survey of 34 shield lakes in Ontario and Quebec, pH 4.4 to 7.1, was made to evaluate which metals should be considered of concern as a risk to aquatic biota or consumers when lakes are acid stressed. A set of predictions, concerning the mobilization by man, the mobility, the chemical speciation, and the toxicity or bioaccumulation of metals in acid-stressed waters, were used as a basis for designing the study and organizing the results. Attached algae were used as biomonitors to assess metal bioavailability. The study concluded that zinc, lead, aluminum, and mercury were of concern in acid-stressed lakes, while the situation for manganese was unresolved, and cadmium was not studied. Nickel and copper were of concern only when a point source was involved. The study also concluded that the attached algal community had some value as a biomonitor, for metals in acid-stressed as well as metal-polluted surface waters. PMID:4076097

Differing responses of the estuarine bivalve Limecola balthica to lowered water pH caused by potential CO2 leaks from a sub-seabed storage site in the Baltic Sea: An experimental study.

PubMed

Sokołowski, Adam; Brulińska, Dominika; Mirny, Zuzanna; Burska, Dorota; Pryputniewicz-Flis, Dorota

2018-02-01

Sub-Seabed CCS is regarded as a key technology for the reduction of CO 2 emissions, but little is known about the mechanisms through which leakages from storage sites impact benthic species. In this study, the biological responses of the infaunal bivalve Limecola balthica to CO 2 -induced seawater acidification (pH7.7, 7.0, and 6.3) were quantified in 56-day mesocosm experiments. Increased water acidity caused changes in behavioral and physiological traits, but even the most acidic conditions did not prove to be fatal. In response to hypercapnia, the bivalves approached the sediment surface and increased respiration rates. Lower seawater pH reduced shell weight and growth, while it simultaneously increased soft tissue weight; this places L. balthica in a somewhat unique position among marine invertebrates. Copyright © 2017 Elsevier Ltd. All rights reserved.

The Submarine Volcano Eruption off El Hierro Island: Effects on the Scattering Migrant Biota and the Evolution of the Pelagic Communities

PubMed Central

Ariza, Alejandro; Kaartvedt, Stein; Røstad, Anders; Garijo, Juan Carlos; Arístegui, Javier; Fraile-Nuez, Eugenio; Hernández-León, Santiago

2014-01-01

The submarine volcano eruption off El Hierro Island (Canary Islands) on 10 October 2011 promoted dramatic perturbation of the water column leading to changes in the distribution of pelagic fauna. To study the response of the scattering biota, we combined acoustic data with hydrographic profiles and concurrent sea surface turbidity indexes from satellite imagery. We also monitored changes in the plankton and nekton communities through the eruptive and post-eruptive phases. Decrease of oxygen, acidification, rising temperature and deposition of chemicals in shallow waters resulted in a reduction of epipelagic stocks and a disruption of diel vertical migration (nocturnal ascent) of mesopelagic organisms. Furthermore, decreased light levels at depth caused by extinction in the volcanic plume resulted in a significant shallowing of the deep acoustic scattering layer. Once the eruption ceased, the distribution and abundances of the pelagic biota returned to baseline levels. There was no evidence of a volcano-induced bloom in the plankton community. PMID:25047077

The submarine volcano eruption off El Hierro Island: effects on the scattering migrant biota and the evolution of the pelagic communities.

PubMed

Ariza, Alejandro; Kaartvedt, Stein; Røstad, Anders; Garijo, Juan Carlos; Arístegui, Javier; Fraile-Nuez, Eugenio; Hernández-León, Santiago

2014-01-01

The submarine volcano eruption off El Hierro Island (Canary Islands) on 10 October 2011 promoted dramatic perturbation of the water column leading to changes in the distribution of pelagic fauna. To study the response of the scattering biota, we combined acoustic data with hydrographic profiles and concurrent sea surface turbidity indexes from satellite imagery. We also monitored changes in the plankton and nekton communities through the eruptive and post-eruptive phases. Decrease of oxygen, acidification, rising temperature and deposition of chemicals in shallow waters resulted in a reduction of epipelagic stocks and a disruption of diel vertical migration (nocturnal ascent) of mesopelagic organisms. Furthermore, decreased light levels at depth caused by extinction in the volcanic plume resulted in a significant shallowing of the deep acoustic scattering layer. Once the eruption ceased, the distribution and abundances of the pelagic biota returned to baseline levels. There was no evidence of a volcano-induced bloom in the plankton community.

Physiological responses to ocean acidification and warming synergistically reduce condition of the common cockle Cerastoderma edule.

PubMed

Ong, E Z; Briffa, M; Moens, T; Van Colen, C

2017-09-01

The combined effect of ocean acidification and warming on the common cockle Cerastoderma edule was investigated in a fully crossed laboratory experiment. Survival of the examined adult organisms remained high and was not affected by elevated temperature (+3 °C) or lowered pH (-0.3 units). However, the morphometric condition index of the cockles incubated under high pCO 2 conditions (i.e. combined warming and acidification) was significantly reduced after six weeks of incubation. Respiration rates increased significantly under low pH, with highest rates measured under combined warm and low pH conditions. Calcification decreased significantly under low pH while clearance rates increased significantly under warm conditions and were generally lower in low pH treatments. The observed physiological responses suggest that the reduced food intake under hypercapnia is insufficient to support the higher energy requirements to compensate for the higher costs for basal maintenance and growth in future high pCO 2 waters. Copyright © 2017 Elsevier Ltd. All rights reserved.

Soil-solution partitioning of DOC in acid organic soils: Results from a UK field acidification and alkalization experiment

NASA Astrophysics Data System (ADS)

Oulehle, Filip; Jones, Timothy; Burden, Annette; Evans, Chris

2013-04-01

Dissolved organic carbon (DOC) is an important component of the global carbon (C) cycle and has profound impacts on water chemistry and metabolism in lakes and rivers. Reported increases of DOC concentration in surface waters across Europe and Northern America have been attributed to several drivers; from changing climate and land-use to eutrophication and declining acid deposition. The last of these suggests that acidic deposition suppressed the solubility of DOC, and that this historic suppression is now being reversed by reducing emissions of acidifying pollutants. We studied a set of four parallel acidification and alkalization experiments in organic rich soils which, after three years of manipulation, have shown clear soil solution DOC responses to acidity change. We tested whether these DOC concentration changes were related to changes in the acid/base properties of DOC. Based on laboratory determination of DOC site density (S.D. = amount of carboxylic groups per milligram DOC) and charge density (C.D. = organic acid anion concentration per milligram DOC) we found that the change in DOC soil-solution partitioning was tightly related to the change in degree of dissociation (α = C.D./S.D. ratio) of organic acids (R2=0.74, p<0.01). Carbon turnover in soil organic matter (SOM), determined by soil respiration and β-D-glucosidase enzyme activity measurements, also appears to have some impact on DOC leaching, via constraints on the actual supply of available DOC from SOM; when the turnover rate of C in SOM is low, the effect of α on DOC leaching is reduced. Thus, differences in the magnitude of DOC changes seen across different environments might be explained by interactions between physicochemical restrictions of DOC soil-solution partitioning, and SOM carbon turnover effects on DOC supply.

Multi-decadal Records of Ocean Acidification and Toxic Heavy Metal Pollution in Coral Cores from Oahu, Hawaii

NASA Astrophysics Data System (ADS)

Stewart, J.; Tolliver, R.; Field, D. B.; Young, C.; Stafford, G.; Day, R. D.

2016-12-01

Monitoring of the physiological/ecological response of marine calcifying organisms to the combination of lower pH and toxic metal pollutants (e.g. Cu and Sn from boat anti-fouling paints) into the oceans requires detailed knowledge of the rates and spatial distribution of ocean acidification (OA) and trace metal composition over time. Yet, measurement of metal concentrations and carbonate system parameters in the modern ocean from seawater bottle data is patchy (e.g. CDIAC/WOCE Carbon Data; http://cdiac.ornl.gov) and there remain few long-term surface water pH monitoring stations; the two longest continuous records of ocean pH extend back less than 30 years (Bermuda - BATS, 31°40'N, 64°10'W; Hawaii - HOTs, 22°45'N, 158°00'W). Much attention has therefore been focused on trace metal and ocean carbonate system proxy development to allow reconstruction of seawater metal content and pH in the past. Of particular promise is the boron isotope (δ11B) pH-proxy measured in marine calcifying organisms such as coral that can be cored enabling multi-decadal, annual-resolution, records of trace element incorporation and seawater pH to be generated. Here we present continuous Cu/Ca and Sn/Ca records in addition to δ11B data from three coral cores of Porites lutea. collected from waters proximal to Oahu, Hawaii. The diagenetic integrity of samples is verified using X-ray diffraction to assess the degree of calcite replacement. These cores reach a maximum depth of 80 cm and represent approximately 80 years of coral growth and seawater chemistry.

Numerical modelling of physiological and ecological impacts of ocean acidification on coccolithophores

NASA Astrophysics Data System (ADS)

Furukawa, Makoto; Sato, Toru; Suzuki, Yoshimi; Casareto, Beatriz E.; Hirabayashi, Shinichiro

2018-06-01

Ocean surface acidification due to increasing atmospheric CO2 concentration is currently attracting much attention. Coccolithophores distribute widely across the world's oceans and represent a carbon sink containing about 100 million tonnes of carbon. For this reason, there is concern about dissolution of their shells, which are made of calcium carbonate, due to decreasing pH. In this study, intracellular calcification, photosynthesis, and mass transport through biomembranes of Emiliania huxleyi were modelled numerically for understanding biological response in calcifying organisms. Unknown parameters were optimised by a generic algorithm to match existing experimental results. The model showed that the production of calcium carbonate rather than its dissolution is promoted under an acidified environment. Calcite remains at saturation levels in a coccolith even when it is below saturation levels in the external seawater. Furthermore, a coccolith can dissolve even in water where calcite saturation exceeds 1, because the saturation may be below the threshold level locally around the cell membrane. The present model also showed that the different calcification rates of E. huxleyi with respect to rising CO2 concentrations reported in the literature are due to differences in experimental conditions; in particular, how the CO2 concentration is matched. Lastly, the model was able to reproduce differences in calcification rates among coccolithophore species. The above biochemical-kinetic model was then incorporated into an ecosystem model, and the behaviour of coccolithophores in the ecosystem and the influence of increases in CO2 concentration on water quality were simulated and validated by comparison with existing experimental results. The model also suggests that increased CO2 concentration could lead to an increase in the biomass ratio of coccolithophores to diatoms at high CO2 concentrations, particularly in oligotrophic environments, and to a consequent decrease in pH due to calcium dissolution.

Coupled greenhouse warming and deep-sea acidification in the middle Eocene

NASA Astrophysics Data System (ADS)

Bohaty, Steven M.; Zachos, James C.; Florindo, Fabio; Delaney, Margaret L.

2009-06-01

The Middle Eocene Climatic Optimum (MECO) is an enigmatic warming event that represents an abrupt reversal in long-term cooling through the Eocene. In order to further assess the timing and nature of this event, we have assembled stable isotope and calcium carbonate concentration records from multiple Deep Sea Drilling Project and Ocean Drilling Program sites for the time interval between ˜43 and 38 Ma. Revised stratigraphy at several sites and compilation of δ18O records place peak warming during the MECO event at 40.0 Ma (Chron C18n.2n). The identification of the δ18O excursion at sites in different geographic regions indicates that the climatic effects of this event were globally extensive. The total duration of the MECO event is estimated at ˜500 ka, with peak warming lasting <100 ka. Assuming minimal glaciation in the late middle Eocene, ˜4°-6°C total warming of both surface and deep waters is estimated during the MECO at the study sites. The interval of peak warming at ˜40.0 Ma also coincided with a worldwide decline in carbonate accumulation at sites below 3000 m depth, reflecting a temporary shoaling of the calcite compensation depth. The synchroneity of deep-water acidification and globally extensive warming makes a persuasive argument that the MECO event was linked to a transient increase in atmospheric pCO2. The results of this study confirm previous reports of significant climatic instability during the middle Eocene. Furthermore, the direct link between warming and changes in the carbonate chemistry of the deep ocean provides strong evidence that changes in greenhouse gas concentrations exerted a primary control on short-term climate variability during this critical period of Eocene climate evolution.

Interactive effects of elevated temperature and CO2 levels on energy metabolism and biomineralization of marine bivalves Crassostrea virginica and Mercenaria mercenaria.

PubMed

Ivanina, Anna V; Dickinson, Gary H; Matoo, Omera B; Bagwe, Rita; Dickinson, Ashley; Beniash, Elia; Sokolova, Inna M

2013-09-01

The continuing increase of carbon dioxide (CO2) levels in the atmosphere leads to increases in global temperatures and partial pressure of CO2 (PCO2) in surface waters, causing ocean acidification. These changes are especially pronounced in shallow coastal and estuarine waters and are expected to significantly affect marine calcifiers including bivalves that are ecosystem engineers in estuarine and coastal communities. To elucidate potential effects of higher temperatures and PCO2 on physiology and biomineralization of marine bivalves, we exposed two bivalve species, the eastern oysters Crassostrea virginica and the hard clams Mercenaria mercenaria to different combinations of PCO2 (~400 and 800μatm) and temperatures (22 and 27°C) for 15weeks. Survival, bioenergetic traits (tissue levels of lipids, glycogen, glucose and high energy phosphates) and biomineralization parameters (mechanical properties of the shells and activity of carbonic anhydrase, CA) were determined in clams and oysters under different temperature and PCO2 regimes. Our analysis showed major inter-species differences in shell mechanical traits and bioenergetics parameters. Elevated temperature led to the depletion of tissue energy reserves indicating energy deficiency in both species and resulted in higher mortality in oysters. Interestingly, while elevated PCO2 had a small effect on the physiology and metabolism of both species, it improved survival in oysters. At the same time, a combination of high temperature and elevated PCO2 lead to a significant decrease in shell hardness in both species, suggesting major changes in their biomineralization processes. Overall, these studies show that global climate change and ocean acidification might have complex interactive effects on physiology, metabolism and biomineralization in coastal and estuarine marine bivalves. Copyright © 2013 Elsevier Inc. All rights reserved.

Acid rain recovery may help to mitigate the impacts of climate change on thermally sensitive fish in lakes across eastern North America.

PubMed

Warren, Dana R; Kraft, Clifford E; Josephson, Daniel C; Driscoll, Charles T

2017-06-01

From the 1970s to 1990s, more stringent air quality regulations were implemented across North America and Europe to reduce chemical emissions that contribute to acid rain. Surface water pH slowly increased during the following decades, but biological recovery lagged behind chemical recovery. Fortunately, this situation is changing. In the past few years, northeastern US fish populations have begun to recover in lakes that were historically incapable of sustaining wild fish due to acidic conditions. As lake ecosystems across the eastern United States recover from acid deposition, the stress to the most susceptible populations of native coldwater fish appears to be shifting from acidification effects to thermal impacts associated with changing climate. Extreme summer temperature events - which are expected to occur with increasing frequency in the coming century - can stress and ultimately kill native coldwater fish in lakes where thermal stratification is absent or highly limited. Based on data from northeastern North America, we argue that recovery from acid deposition has the potential to improve the resilience of coldwater fish populations in some lakes to impacts of climate change. This will occur as the amount of dissolved organic carbon (DOC) in the water increases with increasing lake pH. Increased DOC will reduce water clarity and lead to shallower and more persistent lake thermoclines that can provide larger areas of coldwater thermal refuge habitat. Recovery from acidification will not eliminate the threat of climate change to coldwater fish, but secondary effects of acid recovery may improve the resistance of coldwater fish populations in lakes to the effects of elevated summer temperatures in historically acidified ecosystems. This analysis highlights the importance of considering the legacy of past ecosystem impacts and how recovery or persistence of those effects may interact with climate change impacts on biota in the coming decades. © 2016 John Wiley & Sons Ltd.

Reversible and irreversible impacts of greenhouse gas emissions in multi-century projections with the NCAR global coupled carbon cycle-climate model

NASA Astrophysics Data System (ADS)

Froelicher, T. L.; Joos, F.

2010-12-01

The legacy of historical and the long-term impacts of 21st century greenhouse gas emissions on climate, ocean acidification, and carbon-climate feedbacks are investigated with a coupled carbon cycle-climate model. Emission commitment scenarios with zero emissions after year 2100 and 21st century emissions of 1,800, 900, and 0 gigatons of carbon are run up to year 2500. The reversibility and irreversibility of impacts is quantified by comparing anthropogenically-forced regional changes with internal, unforced climate variability. We show that the influence of historical emissions and of non-CO2 agents is largely reversible on the regional scale. Forced changes in surface temperature and precipitation become smaller than internal variability for most land and ocean grid cells in the absence of future carbon emissions. In contrast, continued carbon emissions over the 21st century cause irreversible climate change on centennial to millennial timescales in most regions and impacts related to ocean acidification and sea level rise continue to aggravate for centuries even if emissions are stopped in year 2100. Undersaturation of the Arctic surface ocean with respect to aragonite, a mineral form of calcium carbonate secreted by marine organisms, is imminent and remains widespread. The volume of supersaturated water providing habitat to calcifying organisms is reduced from preindustrial 40 to 25% in 2100 and to 10% in 2300 for the high emission case. We conclude that emission trading schemes, related to the Kyoto Process,should not permit trading between emissions of relatively short-lived agents and CO2 given the irreversible impacts of anthropogenic carbon emissions.

Reversible and irreversible impacts of greenhouse gas emissions in multi-century projections with the NCAR global coupled carbon cycle-climate model

NASA Astrophysics Data System (ADS)

Frölicher, Thomas L.; Joos, Fortunat

2010-12-01

The legacy of historical and the long-term impacts of 21st century greenhouse gas emissions on climate, ocean acidification, and carbon-climate feedbacks are investigated with a coupled carbon cycle-climate model. Emission commitment scenarios with zero emissions after year 2100 and 21st century emissions of 1,800, 900, and 0 gigatons of carbon are run up to year 2500. The reversibility and irreversibility of impacts is quantified by comparing anthropogenically-forced regional changes with internal, unforced climate variability. We show that the influence of historical emissions and of non-CO2 agents is largely reversible on the regional scale. Forced changes in surface temperature and precipitation become smaller than internal variability for most land and ocean grid cells in the absence of future carbon emissions. In contrast, continued carbon emissions over the 21st century cause irreversible climate change on centennial to millennial timescales in most regions and impacts related to ocean acidification and sea level rise continue to aggravate for centuries even if emissions are stopped in year 2100. Undersaturation of the Arctic surface ocean with respect to aragonite, a mineral form of calcium carbonate secreted by marine organisms, is imminent and remains widespread. The volume of supersaturated water providing habitat to calcifying organisms is reduced from preindustrial 40 to 25% in 2100 and to 10% in 2300 for the high emission case. We conclude that emission trading schemes, related to the Kyoto Process, should not permit trading between emissions of relatively short-lived agents and CO2 given the irreversible impacts of anthropogenic carbon emissions.

Significance of a Shelf-wide Dissolution Event during the Paleocene-Eocene Thermal Maximum, Maryland and New Jersey, USA

NASA Astrophysics Data System (ADS)

Bralower, T. J.; Kump, L. R.; Robinson, M. M.; Self-Trail, J. M.; Zachos, J. C.

2016-12-01

Continental-shelf sediments of the US Atlantic margin experienced a brief episode of carbonate dissolution during the onset of the Paleocene-Eocene Thermal Maximum (PETM). Dissolution is represented by reduced percentages of carbonate, and calcareous microfossil distribution and preservation trends, in cores from Maryland and New Jersey. The base and the top of the dissolution zone are abrupt compared to the gradual nature of the onset of the carbon isotope excursion (CIE). The thickness of the dissolution zone varies from 9 cm in the Bass River core (outer paleoshelf) to 1.6 m in the CamDor core (middle paleoshelf). The decrease in %CaCO3 suggests dissolution locally removed 83 to 100% of the initial biogenic carbonate. Shelf-wide dissolution during the onset of the PETM may be a regional event, associated, for example, with eutrophication. Samples from across the paleoshelf contain abundant fine-grained framboidal pyrite, which suggests photic-zone euxinia occurred before, during, and after the dissolution event. Dissolution may also be associated with oxidation of this pyrite during later exposure to oxidizing groundwaters, although the restricted duration of the dissolution interval argues against this. Alternatively, the dissolution event may have global significance related to surface ocean-water acidification or shoaling of the calcite compensation depth (CCD) to shelf depths. The event began near the onset of the CIE on the shelf, whereas dissolution in deep-sea sections began later. Earlier shelf dissolution is consistent with surface ocean acidification while later deep-sea dissolution is thought to be associated with shoaling of the CCD. In our presentation, we weigh evidence for each of these possibilities and test them using the global dataset.

Understanding the nature of atmospheric acid processing of mineral dusts in supplying bioavailable phosphorus to the oceans

PubMed Central

Krom, Michael D.; Mortimer, Robert J. G.; Benning, Liane G.; Herbert, Ross J.; Shi, Zongbo; Kanakidou, Maria; Nenes, Athanasios

2016-01-01

Acidification of airborne dust particles can dramatically increase the amount of bioavailable phosphorus (P) deposited on the surface ocean. Experiments were conducted to simulate atmospheric processes and determine the dissolution behavior of P compounds in dust and dust precursor soils. Acid dissolution occurs rapidly (seconds to minutes) and is controlled by the amount of H+ ions present. For H+ < 10−4 mol/g of dust, 1–10% of the total P is dissolved, largely as a result of dissolution of surface-bound forms. At H+ > 10−4 mol/g of dust, the amount of P (and calcium) released has a direct proportionality to the amount of H+ consumed until all inorganic P minerals are exhausted and the final pH remains acidic. Once dissolved, P will stay in solution due to slow precipitation kinetics. Dissolution of apatite-P (Ap-P), the major mineral phase in dust (79–96%), occurs whether calcium carbonate (calcite) is present or not, although the increase in dissolved P is greater if calcite is absent or if the particles are externally mixed. The system was modeled adequately as a simple mixture of Ap-P and calcite. P dissolves readily by acid processes in the atmosphere in contrast to iron, which dissolves more slowly and is subject to reprecipitation at cloud water pH. We show that acidification can increase bioavailable P deposition over large areas of the globe, and may explain much of the previously observed patterns of variability in leachable P in oceanic areas where primary productivity is limited by this nutrient (e.g., Mediterranean). PMID:27930294

Apparent increase in coccolithophore abundance in the subtropical North Atlantic from 1990 to 2014

NASA Astrophysics Data System (ADS)

Krumhardt, Kristen M.; Lovenduski, Nicole S.; Freeman, Natalie M.; Bates, Nicholas R.

2016-02-01

As environmental conditions evolve with rapidly increasing atmospheric CO2, biological communities will change as species reorient their distributions, adapt, or alter their abundance. In the surface ocean, dissolved inorganic carbon (DIC) has been increasing over the past several decades as anthropogenic CO2 dissolves into seawater, causing acidification (decreases in pH and carbonate ion concentration). Calcifying phytoplankton, such as coccolithophores, are thought to be especially vulnerable to ocean acidification. How coccolithophores will respond to increasing carbon input has been a subject of much speculation and inspired numerous laboratory and mesocosm experiments, but how they are currently responding in situ is less well documented. In this study, we use coccolithophore (haptophyte) pigment data collected at the Bermuda Atlantic Time-series Study (BATS) site together with satellite estimates (1998-2014) of surface chlorophyll and particulate inorganic carbon (PIC) as a proxy for coccolithophore abundance to show that coccolithophore populations in the North Atlantic subtropical gyre have been increasing significantly over the past 2 decades. Over 1990-2012, we observe a 37 % increase in euphotic zone-integrated coccolithophore pigment abundance at BATS, though we note that this is sensitive to the period being analyzed. We further demonstrate that variability in coccolithophore chlorophyll a here is positively correlated with variability in nitrate and DIC (and especially the bicarbonate ion) in the upper 30 m of the water column. Previous studies have suggested that coccolithophore photosynthesis may benefit from increasing CO2, but calcification may eventually be hindered by low pHT (< 7.7). Given that DIC has been increasing at BATS by ˜ 1.4 µmol kg-1 yr-1 over the period of 1991-2012, we speculate that coccolithophore photosynthesis and perhaps calcification may have increased in response to anthropogenic CO2 input.

Vulnerability of polar oceans to anthropogenic acidification: comparison of arctic and antarctic seasonal cycles.

PubMed

Shadwick, E H; Trull, T W; Thomas, H; Gibson, J A E

2013-01-01

Polar oceans are chemically sensitive to anthropogenic acidification due to their relatively low alkalinity and correspondingly weak carbonate buffering capacity. Here, we compare unique CO2 system observations covering complete annual cycles at an Arctic (Amundsen Gulf) and Antarctic site (Prydz Bay). The Arctic site experiences greater seasonal warming (10 vs 3°C), and freshening (3 vs 2), has lower alkalinity (2220 vs 2320 μmol/kg), and lower summer pH (8.15 vs 8.5), than the Antarctic site. Despite a larger uptake of inorganic carbon by summer photosynthesis, the Arctic carbon system exhibits smaller seasonal changes than the more alkaline Antarctic system. In addition, the excess surface nutrients in the Antarctic may allow mitigation of acidification, via CO2 removal by enhanced summer production driven by iron inputs from glacial and sea-ice melting. These differences suggest that the Arctic system is more vulnerable to anthropogenic change due to lower alkalinity, enhanced warming, and nutrient limitation.

Vulnerability of Polar Oceans to Anthropogenic Acidification: Comparison of Arctic and Antarctic Seasonal Cycles

PubMed Central

Shadwick, E. H.; Trull, T. W.; Thomas, H.; Gibson, J. A. E.

2013-01-01

Polar oceans are chemically sensitive to anthropogenic acidification due to their relatively low alkalinity and correspondingly weak carbonate buffering capacity. Here, we compare unique CO2 system observations covering complete annual cycles at an Arctic (Amundsen Gulf) and Antarctic site (Prydz Bay). The Arctic site experiences greater seasonal warming (10 vs 3°C), and freshening (3 vs 2), has lower alkalinity (2220 vs 2320 μmol/kg), and lower summer pH (8.15 vs 8.5), than the Antarctic site. Despite a larger uptake of inorganic carbon by summer photosynthesis, the Arctic carbon system exhibits smaller seasonal changes than the more alkaline Antarctic system. In addition, the excess surface nutrients in the Antarctic may allow mitigation of acidification, via CO2 removal by enhanced summer production driven by iron inputs from glacial and sea-ice melting. These differences suggest that the Arctic system is more vulnerable to anthropogenic change due to lower alkalinity, enhanced warming, and nutrient limitation. PMID:23903871

Effect of acidification conditions on the properties of carbon nanotube fibers

NASA Astrophysics Data System (ADS)

Wang, Kun; Li, Min; Liu, Ya-Nan; Gu, Yizhuo; Li, Qingwen; Zhang, Zuoguang

2014-02-01

Carbon nanotube (CNT) fibers prepared by dry-spun method were functionalized by mixture of nitric and sulfuric acids. The effects of acidification conditions on the electrical conductivity and tensile properties of CNT fibers were investigated. A strong, high conductive CNT fiber was obtained under the optimal mixture ratio and processing time, with a electrical conductivity and tensile strength up to 3.2 × 104 S/m and 1103 MPa, respectively. It showed that the acids densified the surface of the CNT fiber and introduced functional groups onto the tubes, both of which contributed to the conductivity improvement of the CNT fiber. The infrared spectroscopy, Raman and fracture analysis indicated that acidification process resulted in two competitive effects on the tensile properties of CNT fibers, one was the positive contribution by the enhancement of interactions between CNTs through the densification and functional groups, and the other was the negative effect due to the structural destruction of the tubes.

Electrochemically induced disintegration of layer-by-layer-assembled thin films composed of 2-iminobiotin-labeled poly(ethyleneimine) and avidin.

PubMed

Sato, Katsuhiko; Kodama, Daisuke; Naka, Yukihisa; Anzai, Jun-ichi

2006-12-01

A layer-by-layer assembly composed of avidin and 2-iminobiotin-labeled poly(ethyleneimine) (ib-PEI) was prepared on the surface of a platinum (Pt) film-coated quartz resonator, and an electrochemically induced disintegration of the avidin-ib-PEI assembly was studied using a quartz crystal microbalance. The resonance frequency of a five-bilayer (avidin-ib-PEI)5 film-coated quartz resonator was increased upon application of an electric potential to the Pt layer of the quartz resonator, suggesting that the mass on the quartz resonator was decreased as a result of disintegration of the (avidin-ib-PEI)5 film, due to a pH change in the vicinity of the surface of the Pt-coated quartz resonator. It may be that the (avidin-ib-PEI)5 film assembly was decomposed by acidification of the local pH on the surface of the Pt layer, which in turn was induced through electrolysis of water on Pt, because ib-PEI forms complexes with avidin only in basic media. In pH 9 solution, the (avidin-ib-PEI)5 film was decomposed under the influence of an applied potential of 0.6-1.0 V versus Ag/AgCl. The (avidin-ib-PEI)5 film was decomposed almost completely within a minute in a low concentration buffer (1 mM, pH 9), while the decomposition was slower in 10 and 100 mM buffer solutions at the same pH. The decomposition of the assembly was rapid when the electrode potential was applied in pH 9 solutions, while the response was relatively slow in pH 10 and 11 solutions. All the results are rationalized on the basis of an electrochemically induced acidification of the local environment around the (avidin-ib-PEI)5 film on the Pt layer.

Effects of Habitat Characteristics and Water Quality on Macroinvertebrate Communities along the Neversink Riverin Southeastern New York, 1991-2001

USGS Publications Warehouse

Ernst, Anne G.; Baldigo, Barry P.; Schuler, George E.; Apse, Colin D.; Carter, James L.; Lester, Gary T.

2008-01-01

The Neversink River, in the Catskill Mountains of southeastern New York State, feeds the Neversink Reservoir, which diverts 85 percent of the river?s flow to New York City. Acidification of several headwater reaches has affected macroinvertebrate assemblages throughout the river system above the reservoir, and the alteration of flow conditions below the reservoir dam has affected macroinvertebrate assemblages for at least 10 kilometers downstream from the reservoir. In 1999, the U.S. Geological Survey, in cooperation with The Nature Conservancy, compiled data from 30 stream reaches to quantify the effects of acidification and of the reservoir on the structure and function of macroinvertebrate assemblages throughout the Neversink River. Acidic headwater reaches supported greater numbers of acid-tolerant chironomid taxa and fewer numbers of acid-sensitive Ephemeroptera and Trichoptera than neutral reaches, and fewer scraper individuals and more shredder individuals. The 14 reaches below the reservoir, with sharply decreased flows and altered flow patterns compared to reaches above the reservoir, supported more Chironomidae and fewer Ephemeroptera and Trichoptera than the upper reaches; they also had greater numbers of shredder individuals and fewer scraper and filterer individuals than reaches above the reservoir. Water-quality variables such as pH and aluminum concentration appear to have affected macroinvertebrate assemblages more strongly in the headwaters than below the reservoir, whereas physical-habitat variables such as mean channel width and water temperature have affected these assemblages more strongly downstream from the reservoir than in the headwaters. The water-quality changes due to acidification, combined with the decreased flows and lowered water temperatures below the reservoir, have disrupted downstream continuum of macroinvertebrate communities that would normally be observed from the headwaters to the mouth. The information presented herein provides a basis for further evaluation of the Neversink and similar river systems, and for assessment of the effectiveness of future conservation efforts.

CO2-induced ocean acidification increases anxiety in Rockfish via alteration of GABAA receptor functioning

PubMed Central

Hamilton, Trevor James; Holcombe, Adam; Tresguerres, Martin

2014-01-01

The average surface pH of the ocean is dropping at a rapid rate due to the dissolution of anthropogenic CO2, raising concerns for marine life. Additionally, some coastal areas periodically experience upwelling of CO2-enriched water with reduced pH. Previous research has demonstrated ocean acidification (OA)-induced changes in behavioural and sensory systems including olfaction, which is due to altered function of neural gamma-aminobutyric acid type A (GABAA) receptors. Here, we used a camera-based tracking software system to examine whether OA-dependent changes in GABAA receptors affect anxiety in juvenile Californian rockfish (Sebastes diploproa). Anxiety was estimated using behavioural tests that measure light/dark preference (scototaxis) and proximity to an object. After one week in OA conditions projected for the next century in the California shore (1125 ± 100 µatm, pH 7.75), anxiety was significantly increased relative to controls (483 ± 40 µatm CO2, pH 8.1). The GABAA-receptor agonist muscimol, but not the antagonist gabazine, caused a significant increase in anxiety consistent with altered Cl− flux in OA-exposed fish. OA-exposed fish remained more anxious even after 7 days back in control seawater; however, they resumed their normal behaviour by day 12. These results show that OA could severely alter rockfish behaviour; however, this effect is reversible. PMID:24285203

CO2-induced ocean acidification increases anxiety in rockfish via alteration of GABAA receptor functioning.

PubMed

Hamilton, Trevor James; Holcombe, Adam; Tresguerres, Martin

2014-01-22

The average surface pH of the ocean is dropping at a rapid rate due to the dissolution of anthropogenic CO2, raising concerns for marine life. Additionally, some coastal areas periodically experience upwelling of CO2-enriched water with reduced pH. Previous research has demonstrated ocean acidification (OA)-induced changes in behavioural and sensory systems including olfaction, which is due to altered function of neural gamma-aminobutyric acid type A (GABAA) receptors. Here, we used a camera-based tracking software system to examine whether OA-dependent changes in GABAA receptors affect anxiety in juvenile Californian rockfish (Sebastes diploproa). Anxiety was estimated using behavioural tests that measure light/dark preference (scototaxis) and proximity to an object. After one week in OA conditions projected for the next century in the California shore (1125 ± 100 µatm, pH 7.75), anxiety was significantly increased relative to controls (483 ± 40 µatm CO2, pH 8.1). The GABAA-receptor agonist muscimol, but not the antagonist gabazine, caused a significant increase in anxiety consistent with altered Cl(-) flux in OA-exposed fish. OA-exposed fish remained more anxious even after 7 days back in control seawater; however, they resumed their normal behaviour by day 12. These results show that OA could severely alter rockfish behaviour; however, this effect is reversible.

Plastic responses of bryozoans to ocean acidification.

PubMed

Swezey, Daniel S; Bean, Jessica R; Hill, Tessa M; Gaylord, Brian; Ninokawa, Aaron T; Sanford, Eric

2017-12-01

Phenotypic plasticity has the potential to allow organisms to respond rapidly to global environmental change, but the range and effectiveness of these responses are poorly understood across taxa and growth strategies. Colonial organisms might be particularly resilient to environmental stressors, as organizational modularity and successive asexual generations can allow for distinctively flexible responses in the aggregate form. We performed laboratory experiments to examine the effects of increasing dissolved carbon dioxide (CO 2 ) (i.e. ocean acidification) on the colonial bryozoan Celleporella cornuta sampled from two source populations within a coastal upwelling region of the northern California coast. Bryozoan colonies were remarkably plastic under these CO 2 treatments. Colonies raised under high CO 2 grew more quickly, investing less in reproduction and producing lighter skeletons when compared with genetically identical clones raised under current surface atmosphere CO 2 values. Bryozoans held under high CO 2 conditions also changed the Mg/Ca ratio of skeletal calcite and increased the expression of organic coverings in new growth, which may serve as protection against acidified water. We also observed strong differences between source populations in reproductive investment and organic covering reaction norms, consistent with adaptive responses to persistent spatial variation in local oceanographic conditions. Our results demonstrate that phenotypic plasticity and energetic trade-offs can mediate biological responses to global environmental change, and highlight the broad range of strategies available to colonial organisms. © 2017. Published by The Company of Biologists Ltd.

Diurnal fluctuations in seawater pH influence the response of a calcifying macroalga to ocean acidification

PubMed Central

Cornwall, Christopher E.; Hepburn, Christopher D.; McGraw, Christina M.; Currie, Kim I.; Pilditch, Conrad A.; Hunter, Keith A.; Boyd, Philip W.; Hurd, Catriona L.

2013-01-01

Coastal ecosystems that are characterized by kelp forests encounter daily pH fluctuations, driven by photosynthesis and respiration, which are larger than pH changes owing to ocean acidification (OA) projected for surface ocean waters by 2100. We investigated whether mimicry of biologically mediated diurnal shifts in pH—based for the first time on pH time-series measurements within a kelp forest—would offset or amplify the negative effects of OA on calcifiers. In a 40-day laboratory experiment, the calcifying coralline macroalga, Arthrocardia corymbosa, was exposed to two mean pH treatments (8.05 or 7.65). For each mean, two experimental pH manipulations were applied. In one treatment, pH was held constant. In the second treatment, pH was manipulated around the mean (as a step-function), 0.4 pH units higher during daylight and 0.4 units lower during darkness to approximate diurnal fluctuations in a kelp forest. In all cases, growth rates were lower at a reduced mean pH, and fluctuations in pH acted additively to further reduce growth. Photosynthesis, recruitment and elemental composition did not change with pH, but δ13C increased at lower mean pH. Including environmental heterogeneity in experimental design will assist with a more accurate assessment of the responses of calcifiers to OA. PMID:24107535

The response of Antarctic sea ice algae to changes in pH and CO2.

PubMed

McMinn, Andrew; Müller, Marius N; Martin, Andrew; Ryan, Ken G

2014-01-01

Ocean acidification substantially alters ocean carbon chemistry and hence pH but the effects on sea ice formation and the CO2 concentration in the enclosed brine channels are unknown. Microbial communities inhabiting sea ice ecosystems currently contribute 10-50% of the annual primary production of polar seas, supporting overwintering zooplankton species, especially Antarctic krill, and seeding spring phytoplankton blooms. Ocean acidification is occurring in all surface waters but the strongest effects will be experienced in polar ecosystems with significant effects on all trophic levels. Brine algae collected from McMurdo Sound (Antarctica) sea ice was incubated in situ under various carbonate chemistry conditions. The carbon chemistry was manipulated with acid, bicarbonate and bases to produce a pCO2 and pH range from 238 to 6066 µatm and 7.19 to 8.66, respectively. Elevated pCO2 positively affected the growth rate of the brine algal community, dominated by the unique ice dinoflagellate, Polarella glacialis. Growth rates were significantly reduced when pH dropped below 7.6. However, when the pH was held constant and the pCO2 increased, growth rates of the brine algae increased by more than 20% and showed no decline at pCO2 values more than five times current ambient levels. We suggest that projected increases in seawater pCO2, associated with OA, will not adversely impact brine algal communities.

Slow acidification of the winter mixed layer in the subarctic western North Pacific

NASA Astrophysics Data System (ADS)

Wakita, Masahide; Nagano, Akira; Fujiki, Tetsuichi; Watanabe, Shuichi

2017-08-01

We used carbon dioxide (CO2) system data collected during 1999-2015 to investigate ocean acidification at time series sites in the western subarctic region of the North Pacific Ocean. The annual mean pH at station K2 decreased at a rate of 0.0025 ± 0.0010 year-1 mostly in response to oceanic uptake of anthropogenic CO2. The Revelle factor increased rapidly (0.046 ± 0.022 year-1), an indication that the buffering capacity of this region of the ocean has declined faster than at other time series sites. In the western subarctic region, the pH during the winter decline at a slower rate of 0.0008 ± 0.0004 year-1. This was attributed to a reduced rate of increase of dissolved inorganic carbon (DIC) and an increase of total alkalinity (TA). The reduction of DIC increase was caused by the decline of surface water density associated with the pycnocline depression and the reduction of vertical diffusion flux from the upper pycnocline. These physical changes were probably caused by northward shrinkage of the western subarctic gyre and global warming. Meanwhile, the contribution of the density decline to the TA increase is canceled out by that of the reduced vertical diffusive flux. We speculated that the winter TA increase is caused mainly by the accumulation of TA due to the weakened calcification by organisms during the winter.

Drivers and evolution of episodic acidification at the Bear Brook Watershed in Maine, USA.

PubMed

Laudon, Hjalmar; Norton, Stephen A

2010-12-01

Despite decades of research about episodic acidification in many regions of the world, the understanding of what controls the transient changes in stream water chemistry occurring during rain and snow melt events is still limited. Here, we use 20 years of hydrological and stream chemical data from the paired watershed study at Bear Brook Watershed in Maine (BBWM), USA to improve the understanding of the effects of acid deposition on the causes, drivers, and evolution of episodic acidification. The long-term experimental study at BBWM includes 18 years of chemical treatment of the West Bear Brook (WB) watershed with (NH(4))(2)SO(4). East Bear Brook (EB) serves as reference. The treatment started in 1989 following a 2-year pretreatment period. We analyzed 212 hydrological episodes using an episode model that can separate and quantify individual drivers of the transient change in acid-neutralizing capacity (ANC) during hydrological events. The results suggest that 18 years of N and S addition have not affected the natural drivers of episodic acidification of base-cation dilution, marine sea salt episodes, or organic acidity during rain and snow melt events. The contribution of SO4(2-) to the ANC decline in WB has been increasing linearly since the beginning of watershed treatment, while the role of NO3- has remained relatively constant after an initial increase. This is contradictory to many previous shorter-term studies and illustrates the need for a more mechanistic understanding of the causes and drivers of episodic acidification during rain- and snow melt-driven hydrological events.

Pteropods as indicators for Cumulative Ocean Acidification Exposure

NASA Astrophysics Data System (ADS)

Bednarsek, N.; Klinger, T.

2016-02-01

Pteropods are ubiquitously distributed pelagic marine zooplankton of importance in productive upwelling regimes, where they represent an important prey item for variety of economically, ecologically, and culturally important fish species. Because of their extreme sensitivity to ocean acidification conditions, pteropods can be used to establish cause and effect relationships between OA status and biological condition. Incorporating biological responses into a successful management framework requires laboratory studies that demonstrate sentinel organism responses to specific stressors, while also documenting population or community level effects in the field linked to that stressor. Here, we describe the state of the science and an approach that demonstrates the linkage necessary to use pteropods as a sentinel organism for resource management under conditions of ocean acidification. To demonstrate this utility, newly developed methods were used to determine and quantify pteropod responses in the natural environment. Responses such as shell dissolution, shell calcification, changes in vertical distribution, and survival success were assessed to establish pteropod condition under a variety of OA conditions. While no single species or set of species can adequately capture all aspects of ecosystem change, pteropods represent first quantifiable, specific indicators for ocean acidification's effects on marine systems. The approach can be used in water quality assessments and in living marine resource management as part of the rapid and cost-effective monitoring of biological responses to ocean acidification. The social challenges of changing ocean chemistry will continue to grow in coming decades, making the availability of such straightforward metrics of impact indispensable across scales of time and space of relevance to managers.

Cell-Based Sensor System Using L6 Cells for Broad Band Continuous Pollutant Monitoring in Aquatic Environments

PubMed Central

Kubisch, Rebekka; Bohrn, Ulrich; Fleischer, Maximilian; Stütz, Evamaria

2012-01-01

Pollution of drinking water sources represents a continuously emerging problem in global environmental protection. Novel techniques for real-time monitoring of water quality, capable of the detection of unanticipated toxic and bioactive substances, are urgently needed. In this study, the applicability of a cell-based sensor system using selected eukaryotic cell lines for the detection of aquatic pollutants is shown. Readout parameters of the cells were the acidification (metabolism), oxygen consumption (respiration) and impedance (morphology) of the cells. A variety of potential cytotoxic classes of substances (heavy metals, pharmaceuticals, neurotoxins, waste water) was tested with monolayers of L6 cells (rat myoblasts). The cytotoxicity or cellular effects induced by inorganic ions (Ni2+ and Cu2+) can be detected with the metabolic parameters acidification and respiration down to 0.5 mg/L, whereas the detection limit for other substances like nicotine and acetaminophen are rather high, in the range of 0.1 mg/L and 100 mg/L. In a close to application model a real waste water sample shows detectable signals, indicating the existence of cytotoxic substances. The results support the paradigm change from single substance detection to the monitoring of overall toxicity. PMID:22737014

Cell-based sensor system using L6 cells for broad band continuous pollutant monitoring in aquatic environments.

PubMed

Kubisch, Rebekka; Bohrn, Ulrich; Fleischer, Maximilian; Stütz, Evamaria

2012-01-01

Pollution of drinking water sources represents a continuously emerging problem in global environmental protection. Novel techniques for real-time monitoring of water quality, capable of the detection of unanticipated toxic and bioactive substances, are urgently needed. In this study, the applicability of a cell-based sensor system using selected eukaryotic cell lines for the detection of aquatic pollutants is shown. Readout parameters of the cells were the acidification (metabolism), oxygen consumption (respiration) and impedance (morphology) of the cells. A variety of potential cytotoxic classes of substances (heavy metals, pharmaceuticals, neurotoxins, waste water) was tested with monolayers of L6 cells (rat myoblasts). The cytotoxicity or cellular effects induced by inorganic ions (Ni(2+) and Cu(2+)) can be detected with the metabolic parameters acidification and respiration down to 0.5 mg/L, whereas the detection limit for other substances like nicotine and acetaminophen are rather high, in the range of 0.1 mg/L and 100 mg/L. In a close to application model a real waste water sample shows detectable signals, indicating the existence of cytotoxic substances. The results support the paradigm change from single substance detection to the monitoring of overall toxicity.

The Sulu Sea as Carbon Dioxide Sink

NASA Astrophysics Data System (ADS)

Ferrera, C. M.; Jacinto, G. S.; Chen, C. T. A.

2016-12-01

The Sulu Sea, one of the marginal seas in the West Pacific and the largest internal sea in the Philippines, is characterized by its unique deep water ventilation pattern and high sediment organic carbon and CaCO3 content. Studies on the dissolved CO2 system in the Sulu Sea have remarkably shown that anthropogenic CO2 has already penetrated to the bottom of this 5km-deep basin, albeit limited to a dataset from a single station in December 1996. To further understand the role of this tropical marginal sea as CO2 sink and to assess its behavior as a CO2 sink during the 11-year period, water samples for dissolved CO2 parameters from two deep stations of high productivity and low productivity were collected in December 2007/January 2008 and were compared with the 1996 data. Results suggest that the surface waters in the low productivity region might have been acidifying at a rate of -0.0012 pH unit yr-1. Atmospheric CO2 increased at +1.9 ppmv yr-1 and seawater fCO2 at +3.30 μatm yr-1. Through deep water ventilation, anthropogenic CO2 has penetrated the water column thereby making the deeper waters a sink of anthropogenic CO2. But then the presence and dissolution of CaCO3 deposits at the sea floor and along the Sulu Sea slopes as a result of the reaction with this anthropogenic CO2 probably neutralizes the acidification at depths as shown by the increase in total alkalinity (+0.57 μmol kg-1 yr-1), and facilitates further uptake of CO2 from the atmosphere. Therefore, productivity at Sulu Sea surface waters results to sequestration of CO2 from the atmosphere to the sediment sink through organic carbon and CaCO3 deposits. While high temperature and low productivity surface waters make the Sulu Sea a source of CO2 to the atmosphere, ventilation patterns make the deep waters of the Sulu Sea an efficient sink for anthropogenic CO2. Given the larger area occupied by the CO2 sink deep waters compared to the CO2 source surface waters including an upwelling area, the Sulu Sea could possibly be a "net" CO2 sink, an important contribution to the otherwise underestimated inventory of CO2 from marginal seas.

Limestone fluidized bed treatment of acid-impacted water at the Craig Brook National Fish Hatchery, Maine, USA

USGS Publications Warehouse

Sibrell, P.L.; Watten, B.J.; Haines, T.A.; Spaulding, B.W.

2006-01-01

Decades of atmospheric acid deposition have resulted in widespread lake and river acidification in the northeastern U.S. Biological effects of acidification include increased mortality of sensitive aquatic species such as the endangered Atlantic salmon (Salmo salar). The purpose of this paper is to describe the development of a limestone-based fluidized bed system for the treatment of acid-impacted waters. The treatment system was tested at the Craig Brook National Fish Hatchery in East Orland, Maine over a period of 3 years. The product water from the treatment system was diluted with hatchery water to prepare water supplies with three different levels of alkalinity for testing of fish health and survival. Based on positive results from a prototype system used in the first year of the study, a larger demonstration system was used in the second and third years with the objective of decreasing operating costs. Carbon dioxide was used to accelerate limestone dissolution, and was the major factor in system performance, as evidenced by the model result: Alk = 72.84 ?? P(CO2)1/2; R2 = 0.975. No significant acidic incursions were noted for the control water over the course of the study. Had these incursions occurred, survivability in the untreated water would likely have been much more severely impacted. Treated water consistently provided elevated alkalinity and pH above that of the hatchery source water. ?? 2005 Elsevier B.V. All rights reserved.

The effect of physiological conditions on the surface structure of proteins: Setting the scene for human digestion of emulsions

NASA Astrophysics Data System (ADS)

Maldonado-Valderrama, J.; Gunning, A. P.; Ridout, M. J.; Wilde, P. J.; Morris, V. J.

2009-10-01

Understanding and manipulating the interfacial mechanisms that control human digestion of food emulsions is a crucial step towards improved control of dietary intake. This article reports initial studies on the effects of the physiological conditions within the stomach on the properties of the film formed by the milk protein ( β -lactoglobulin) at the air-water interface. Atomic force microscopy (AFM), surface tension and surface rheology techniques were used to visualize and examine the effect of gastric conditions on the network structure. The effects of changes in temperature, pH and ionic strength on a pre-formed interfacial structure were characterized in order to simulate the actual digestion process. Changes in ionic strength had little effect on the surface properties. In isolation, acidification reduced both the dilatational and the surface shear modulus, mainly due to strong repulsive electrostatic interactions within the surface layer and raising the temperature to body temperature accelerated the rearrangements within the surface layer, resulting in a decrease of the dilatational response and an increase of surface pressure. Together pH and temperature display an unexpected synergism, independent of the ionic strength. Thus, exposure of a pre-formed interfacial β -lactoglobulin film to simulated gastric conditions reduced the surface dilatational modulus and surface shear moduli. This is attributed to a weakening of the surface network in which the surface rearrangements of the protein prior to exposure to gastric conditions might play a crucial role.

Responses of amphibian populations to water and soil factors in experimentally-treated aquatic macrocosms

USGS Publications Warehouse

Sparling, D.W.; Lowe, T.P.; Day, D.; Dolan, K.

1995-01-01

Survival of anuran embryos and tadpoles is reduced in acidic (pH < 5.0) waters under laboratory conditions. However, field data on the presence-absence of amphibian species and acidity are equivocal. This study attempts to reconcile some of this discrepancy by using macrocosms to examine the interaction of soil type and water acidification on free-ranging tadpole populations. Tadpoles were caught with activity traps in 24 aquatic macrocosms experimentally treated with H2SO4 and Al2(SO4)3 and lined with either comparatively high metal, Iow organic matter clay soils or lower metal, higher organic matter loams. Northern cricket frog (Acris crepitans) tadpole abundance was less in acidified macrocosms than in circumneutral ones (p < 0.05) and less in those with loam soils than in macrocosms with clay soils (p < 0.04). Gray treefrog (Hyla versicolor) abundance was affected by an interaction between soil and acidification (p < 0.07) in that treatment effects were only observed in macrocosms with clay soils (p < 0.01). No differences were observed among treatments for green frog (Rana clamitans) or southern leopard frog (R. utricularia) tadpoles. The study shows that soil type may interact with water conditions to affect amphibian populations in acidified waters

Limacina helicina shell dissolution as an indicator of declining habitat suitability owing to ocean acidification in the California Current Ecosystem

PubMed Central

Bednaršek, N.; Feely, R. A.; Reum, J. C. P.; Peterson, B.; Menkel, J.; Alin, S. R.; Hales, B.

2014-01-01

Few studies to date have demonstrated widespread biological impacts of ocean acidification (OA) under conditions currently found in the natural environment. From a combined survey of physical and chemical water properties and biological sampling along the Washington–Oregon–California coast in August 2011, we show that large portions of the shelf waters are corrosive to pteropods in the natural environment. We show a strong positive correlation between the proportion of pteropod individuals with severe shell dissolution damage and the percentage of undersaturated water in the top 100 m with respect to aragonite. We found 53% of onshore individuals and 24% of offshore individuals on average to have severe dissolution damage. Relative to pre-industrial CO2 concentrations, the extent of undersaturated waters in the top 100 m of the water column has increased over sixfold along the California Current Ecosystem (CCE). We estimate that the incidence of severe pteropod shell dissolution owing to anthropogenic OA has doubled in near shore habitats since pre-industrial conditions across this region and is on track to triple by 2050. These results demonstrate that habitat suitability for pteropods in the coastal CCE is declining. The observed impacts represent a baseline for future observations towards understanding broader scale OA effects. PMID:24789895

Limacina helicina shell dissolution as an indicator of declining habitat suitability owing to ocean acidification in the California Current Ecosystem.

PubMed

Bednaršek, N; Feely, R A; Reum, J C P; Peterson, B; Menkel, J; Alin, S R; Hales, B

2014-06-22

Few studies to date have demonstrated widespread biological impacts of ocean acidification (OA) under conditions currently found in the natural environment. From a combined survey of physical and chemical water properties and biological sampling along the Washington-Oregon-California coast in August 2011, we show that large portions of the shelf waters are corrosive to pteropods in the natural environment. We show a strong positive correlation between the proportion of pteropod individuals with severe shell dissolution damage and the percentage of undersaturated water in the top 100 m with respect to aragonite. We found 53% of onshore individuals and 24% of offshore individuals on average to have severe dissolution damage. Relative to pre-industrial CO2 concentrations, the extent of undersaturated waters in the top 100 m of the water column has increased over sixfold along the California Current Ecosystem (CCE). We estimate that the incidence of severe pteropod shell dissolution owing to anthropogenic OA has doubled in near shore habitats since pre-industrial conditions across this region and is on track to triple by 2050. These results demonstrate that habitat suitability for pteropods in the coastal CCE is declining. The observed impacts represent a baseline for future observations towards understanding broader scale OA effects.

Impact of ocean acidification on the early development and escape behavior of marine medaka (Oryzias melastigma).

PubMed

Wang, Xiaojie; Song, Lulu; Chen, Yi; Ran, Haoyu; Song, Jiakun

2017-10-01

Ocean acidification is predicted to affect a wide diversity of marine organisms. However, no studies have reported the effects of ocean acidification on Indian Ocean fish. We have used the Indian Ocean medaka (Oryzias melastigma) as a model species for a marine fish that lives in coastal waters. We investigated the impact of ocean acidification on the embryonic development and the stereotyped escape behavior (mediated by the Mauthner cell) in newly hatched larvae. Newly fertilized eggs of medaka were reared in seawater at three different partial pressures of carbon dioxide (pCO 2 ): control at 450 μatm, moderate at 1160 μatm, and high at 1783 μatm. Hatch rates, embryonic duration, and larval malformation rates were compared and were not significantly different between the treatments and the control. In the high pCO 2 group, however, the yolks of larvae were significantly smaller than in the control group, and the newly hatched larvae were significantly longer than the larvae in the control. In the moderate pCO 2 group, the eye distance decreased significantly. No significantly negative growth effects were observed in the larvae when exposed to pCO 2 levels that are predicted as a result of ocean acidification in the next 100-200 years. Larvae reared under control conditions readily produced C-start escape behavior to mechanosensory stimuli; however, in the moderate and high pCO 2 experimental groups, the probabilities of C-start were significantly lower than those of the control group. Therefore, the sensory integration needed for the C-start escape behavior appears to be vulnerable to ocean acidification. Altered behavior in marine larval fish, particularly behaviors involved in escape from predation, could have potentially negative implications to fish populations, and, further, to the marine ecosystems at the levels of CO 2 projected for the future. Copyright © 2017 Elsevier Ltd. All rights reserved.

Ocean acidification alters early successional coral reef communities and their rates of community metabolism.

PubMed

Noonan, Sam H C; Kluibenschedl, Anna; Fabricius, Katharina E

2018-01-01

Ocean acidification is expected to alter community composition on coral reefs, but its effects on reef community metabolism are poorly understood. Here we document how early successional benthic coral reef communities change in situ along gradients of carbon dioxide (CO2), and the consequences of these changes on rates of community photosynthesis, respiration, and light and dark calcification. Ninety standardised benthic communities were grown on PVC tiles deployed at two shallow-water volcanic CO2 seeps and two adjacent control sites in Papua New Guinea. Along the CO2 gradient, both the upward facing phototrophic and the downward facing cryptic communities changed in their composition. Under ambient CO2, both communities were dominated by calcifying algae, but with increasing CO2 they were gradually replaced by non-calcifying algae (predominantly green filamentous algae, cyanobacteria and macroalgae, which increased from ~30% to ~80% cover). Responses were weaker in the invertebrate communities, however ascidians and tube-forming polychaetes declined with increasing CO2. Differences in the carbonate chemistry explained a far greater amount of change in communities than differences between the two reefs and successional changes from five to 13 months, suggesting community successions are established early and are under strong chemical control. As pH declined from 8.0 to 7.8, rates of gross photosynthesis and dark respiration of the 13-month old reef communities (upper and cryptic surfaces combined) significantly increased by 10% and 20%, respectively, in response to altered community composition. As a consequence, net production remained constant. Light and dark calcification rates both gradually declined by 20%, and low or negative daily net calcification rates were observed at an aragonite saturation state of <2.3. The study demonstrates that ocean acidification as predicted for the end of this century will strongly alter reef communities, and will significantly change rates of community metabolism.

Ocean acidification alters early successional coral reef communities and their rates of community metabolism

PubMed Central

Kluibenschedl, Anna; Fabricius, Katharina E.

2018-01-01

Ocean acidification is expected to alter community composition on coral reefs, but its effects on reef community metabolism are poorly understood. Here we document how early successional benthic coral reef communities change in situ along gradients of carbon dioxide (CO2), and the consequences of these changes on rates of community photosynthesis, respiration, and light and dark calcification. Ninety standardised benthic communities were grown on PVC tiles deployed at two shallow-water volcanic CO2 seeps and two adjacent control sites in Papua New Guinea. Along the CO2 gradient, both the upward facing phototrophic and the downward facing cryptic communities changed in their composition. Under ambient CO2, both communities were dominated by calcifying algae, but with increasing CO2 they were gradually replaced by non-calcifying algae (predominantly green filamentous algae, cyanobacteria and macroalgae, which increased from ~30% to ~80% cover). Responses were weaker in the invertebrate communities, however ascidians and tube-forming polychaetes declined with increasing CO2. Differences in the carbonate chemistry explained a far greater amount of change in communities than differences between the two reefs and successional changes from five to 13 months, suggesting community successions are established early and are under strong chemical control. As pH declined from 8.0 to 7.8, rates of gross photosynthesis and dark respiration of the 13-month old reef communities (upper and cryptic surfaces combined) significantly increased by 10% and 20%, respectively, in response to altered community composition. As a consequence, net production remained constant. Light and dark calcification rates both gradually declined by 20%, and low or negative daily net calcification rates were observed at an aragonite saturation state of <2.3. The study demonstrates that ocean acidification as predicted for the end of this century will strongly alter reef communities, and will significantly change rates of community metabolism. PMID:29847575

Does encapsulation protect embryos from the effects of ocean acidification? The example of Crepidula fornicata.

PubMed

Noisette, Fanny; Comtet, Thierry; Legrand, Erwann; Bordeyne, François; Davoult, Dominique; Martin, Sophie

2014-01-01

Early life history stages of marine organisms are generally thought to be more sensitive to environmental stress than adults. Although most marine invertebrates are broadcast spawners, some species are brooders and/or protect their embryos in egg or capsules. Brooding and encapsulation strategies are typically assumed to confer greater safety and protection to embryos, although little is known about the physico-chemical conditions within egg capsules. In the context of ocean acidification, the protective role of encapsulation remains to be investigated. To address this issue, we conducted experiments on the gastropod Crepidula fornicata. This species broods its embryos within capsules located under the female and veliger larvae are released directly into the water column. C. fornicata adults were reared at the current level of CO2 partial pressure (pCO2) (390 μatm) and at elevated levels (750 and 1400 μatm) before and after fertilization and until larval release, such that larval development occurred entirely at a given pCO2. The pCO2 effects on shell morphology, the frequency of abnormalities and mineralization level were investigated on released larvae. Shell length decreased by 6% and shell surface area by 11% at elevated pCO2 (1400 μatm). The percentage of abnormalities was 1.5- to 4-fold higher at 750 μatm and 1400 μatm pCO2, respectively, than at 390 μatm. The intensity of birefringence, used as a proxy for the mineralization level of the larval shell, also decreased with increasing pCO2. These negative results are likely explained by increased intracapsular acidosis due to elevated pCO2 in extracapsular seawater. The encapsulation of C. fornicata embryos did not protect them against the deleterious effects of a predicted pCO2 increase. Nevertheless, C. fornicata larvae seemed less affected than other mollusk species. Further studies are needed to identify the critical points of the life cycle in this species in light of future ocean acidification.

Reviews and syntheses: Ice acidification, the effects of ocean acidification on sea ice microbial communities

NASA Astrophysics Data System (ADS)

McMinn, Andrew

2017-09-01

Sea ice algae, like some coastal and estuarine phytoplankton, are naturally exposed to a wider range of pH and CO2 concentrations than those in open marine seas. While climate change and ocean acidification (OA) will impact pelagic communities, their effects on sea ice microbial communities remain unclear. Sea ice contains several distinct microbial communities, which are exposed to differing environmental conditions depending on their depth within the ice. Bottom communities mostly experience relatively benign bulk ocean properties, while interior brine and surface (infiltration) communities experience much greater extremes. Most OA studies have examined the impacts on single sea ice algae species in culture. Although some studies examined the effects of OA alone, most examined the effects of OA and either light, nutrients or temperature. With few exceptions, increased CO2 concentration caused either no change or an increase in growth and/or photosynthesis. In situ studies on brine and surface algae also demonstrated a wide tolerance to increased and decreased pH and showed increased growth at higher CO2 concentrations. The short time period of most experiments (< 10 days), together with limited genetic diversity (i.e. use of only a single strain), however, has been identified as a limitation to a broader interpretation of the results. While there have been few studies on the effects of OA on the growth of marine bacterial communities in general, impacts appear to be minimal. In sea ice also, the few reports available suggest no negative impacts on bacterial growth or community richness. Sea ice ecosystems are ephemeral, melting and re-forming each year. Thus, for some part of each year organisms inhabiting the ice must also survive outside of the ice, either as part of the phytoplankton or as resting spores on the bottom. During these times, they will be exposed to the full range of co-stressors that pelagic organisms experience. Their ability to continue to make a major contribution to sea ice productivity will depend not only on their ability to survive in the ice but also on their ability to survive the increasing seawater temperatures, changing distribution of nutrients and declining pH forecast for the water column over the next centuries.

Ocean acidification state in western Antarctic surface waters: drivers and interannual variability

NASA Astrophysics Data System (ADS)

Mattsdotter Björk, M.; Fransson, A.; Chierici, M.

2013-05-01

Each December during four years from 2006 to 2010, the surface water carbonate system was measured and investigated in the Amundsen Sea and Ross Sea, western Antarctica as part of the Oden Southern Ocean expeditions (OSO). The I/B Oden started in Punta Arenas in Chile and sailed southwest, passing through different regimes such as, the marginal/seasonal ice zone, fronts, coastal shelves, and polynyas. Discrete surface water was sampled underway for analysis of total alkalinity (AT), total dissolved inorganic carbon (CT) and pH. Two of these parameters were used together with sea-surface temperature (SST), and salinity to obtain a full description of the surface water carbonate system, including pH in situ and calcium carbonate saturation state of aragonite (ΩAr) and calcite (ΩCa). Multivariate analysis was used to investigate interannual variability and the major controls (sea-ice concentration, SST, salinity and chlorophyll a) on the variability in the carbonate system and Ω. This analysis showed that SST and chlorophyll a were the major drivers of the Ω variability in both the Amundsen and Ross seas. In 2007, the sea-ice edge was located further south and the area of the open polynya was relatively small compared to 2010. We found the lowest pH in situ (7.932) and Ω = 1 values in the sea-ice zone and in the coastal Amundsen Sea, nearby marine out flowing glaciers. In 2010, the sea-ice coverage was the largest and the areas of the open polynyas were the largest for the whole period. This year we found the lowest salinity and AT, coinciding with highest chl a. This implies that the highest ΩAr in 2010 was likely an effect of biological CO2 drawdown, which out-competed the dilution of carbonate ion concentration due to large melt water volumes. We predict and discuss future Ω values, using our data and reported rates of oceanic uptake of anthropogenic CO2, suggesting that the Amundsen Sea will become undersaturated with regard to aragonite about 20 yr sooner than predicted by models.

Influences of riverine and upwelling waters on the coastal carbonate system off Central Chile and their ocean acidification implications

NASA Astrophysics Data System (ADS)

Vargas, Cristian A.; Contreras, Paulina Y.; Pérez, Claudia A.; Sobarzo, Marcus; Saldías, Gonzalo S.; Salisbury, Joe

2016-06-01

A combined data set, combining data from field campaigns and oceanographic cruises, was used to ascertain the influence of both river discharges and upwelling processes, covering spatial and temporal variation in dissolved inorganic carbon (DIC) and aragonite saturation state. This work was conducted in one of the most productive river-influenced upwelling areas in the South Pacific coasts (36°S). Additionally, further work was also conducted to ascertain the contribution of different DIC sources, influencing the dynamics of DIC along the land-ocean range. Six sampling campaigns were conducted across seven stations at the Biobío River basin, covering approximately 200 km. Three research cruises were undertaken simultaneously, covering the adjacent continental shelf, including 12 sampling stations for hydrographic measurements. Additionally, six stations were also sampled for chemical analyses, covering summer, winter, and spring conditions over 2010 and 2011. Our results evidenced that seaward extent of the river plume was more evident during the winter field campaign, when highest riverine DIC fluxes were observed. The carbonate system along the river-ocean continuum was very heterogeneous varying over spatial and temporal scales. High DIC and pCO2 were observed in river areas with larger anthropogenic effects. CO2 supersaturation at the river plume was observed during all campaigns due to the influence of low pH river waters in winter/spring and high-pCO2 upwelling waters in summer. δ13CDIC evidenced that main DIC sources along the river and river plume corresponded to the respiration of terrestrial organic matter. We have linked this natural process to the carbonate saturation on the adjacent river-influenced coastal area, suggesting that Ωaragonite undersaturation in surface/subsurface waters is largely modulated by the influence of both river discharge and coastal upwelling events in this productive coastal area. Conditions of low Ωaragonite might impact negatively physiological traits for marine organisms, such as bivalves, gastropods, and crustaceans. Therefore, local populations from river-influenced sites could be inherently more tolerant to ocean acidification than organisms living in regions with lower Ωaragonite variability.

Toxic diatoms and domoic acid in natural and iron enriched waters of the oceanic Pacific

PubMed Central

Silver, Mary W.; Bargu, Sibel; Coale, Susan L.; Benitez-Nelson, Claudia R.; Garcia, Ana C.; Roberts, Kathryn J.; Sekula-Wood, Emily; Bruland, Kenneth W.; Coale, Kenneth H.

2010-01-01

Near-surface waters ranging from the Pacific subarctic (58°N) to the Southern Ocean (66°S) contain the neurotoxin domoic acid (DA), associated with the diatom Pseudo-nitzschia. Of the 35 stations sampled, including ones from historic iron fertilization experiments (SOFeX, IronEx II), we found Pseudo-nitzschia at 34 stations and DA measurable at 14 of the 26 stations analyzed for DA. Toxin ranged from 0.3 fg·cell−1 to 2 pg·cell−1, comparable with levels found in similar-sized cells from coastal waters. In the western subarctic, descent of intact Pseudo-nitzschia likely delivered significant amounts of toxin (up to 4 μg of DA·m−2·d−1) to underlying mesopelagic waters (150–500 m). By reexamining phytoplankton samples from SOFeX and IronEx II, we found substantial amounts of DA associated with Pseudo-nitzschia. Indeed, at SOFeX in the Antarctic Pacific, DA reached 220 ng·L−1, levels at which animal mortalities have occurred on continental shelves. Iron ocean fertilization also occurs naturally and may have promoted blooms of these ubiquitous algae over previous glacial cycles during deposition of iron-rich aerosols. Thus, the neurotoxin DA occurs both in coastal and oceanic waters, and its concentration, associated with changes in Pseudo-nitzschia abundance, likely varies naturally with climate cycles, as well as with artificial iron fertilization. Given that iron fertilization in iron-depleted regions of the sea has been proposed to enhance phytoplankton growth and, thereby, both reduce atmospheric CO2 and moderate ocean acidification in surface waters, consideration of the potentially serious ecosystem impacts associated with DA is prudent. PMID:21068374

Review of the inorganic geochemistry of peats and peatland waters

NASA Astrophysics Data System (ADS)

Shotyk, William

1988-06-01

The major floristic and geochemical differences between bogs, fens, and swamps are summarized, and the most common peat types described. This is followed by a critical, historical review of the literature. The methods used to measure the pH of peatland (mire) waters are examined, and the pH range of various peatland types is reported. In addition, horizontal and vertical pH variations are illustrated, and factors affecting the pH of these waters reviewed. The cause of the low pH of surface waters of Sphagnum bogs (approximately pH 4) is critically investigated, and the relative importance of dissolved CO 2 and other inorganic acids, and organic acids to the low pH is assessed. Cation exchange on the surfaces of Sphagnum mosses is found to be a relatively unimportant acidification mechanism, but important to the chemical ecology of the plants. The redox chemistry of mire waters is described in terms of the geochemistry of such redox indicators as O 2, CO 2, CH 4, CO, H 2, H 2S, SO 42-, native Cu, and siderite (FeCO 3). Published studies of Eh in peatlands are cited, and the problems of Eh measurement and interpretation are explored. The chemical composition of mire waters (major and trace metals, and nonmetallic species) is examined, and factors affecting their composition reported. The abundance and distribution of mineral matter in peats is described, and the occurrence and formation of minerals of Fe (pyrite and other sulphides, siderite, vivianite), Cu (chalcopyrite, native Cu, covellite) and Zn (smithsonite and wurtzite) investigated. The abundance and distribution of major elements (Si, Al, Na, K, Mg, Ca) and trace metals (Ni, V, Cr, Fe, Mn, Cu, U, Zn, Pb) is described, and factors affecting their solubility examined.

Toxic diatoms and domoic acid in natural and iron enriched waters of the oceanic Pacific.

PubMed

Silver, Mary W; Bargu, Sibel; Coale, Susan L; Benitez-Nelson, Claudia R; Garcia, Ana C; Roberts, Kathryn J; Sekula-Wood, Emily; Bruland, Kenneth W; Coale, Kenneth H

2010-11-30

Near-surface waters ranging from the Pacific subarctic (58°N) to the Southern Ocean (66°S) contain the neurotoxin domoic acid (DA), associated with the diatom Pseudo-nitzschia. Of the 35 stations sampled, including ones from historic iron fertilization experiments (SOFeX, IronEx II), we found Pseudo-nitzschia at 34 stations and DA measurable at 14 of the 26 stations analyzed for DA. Toxin ranged from 0.3 fg·cell(-1) to 2 pg·cell(-1), comparable with levels found in similar-sized cells from coastal waters. In the western subarctic, descent of intact Pseudo-nitzschia likely delivered significant amounts of toxin (up to 4 μg of DA·m(-2)·d(-1)) to underlying mesopelagic waters (150-500 m). By reexamining phytoplankton samples from SOFeX and IronEx II, we found substantial amounts of DA associated with Pseudo-nitzschia. Indeed, at SOFeX in the Antarctic Pacific, DA reached 220 ng·L(-1), levels at which animal mortalities have occurred on continental shelves. Iron ocean fertilization also occurs naturally and may have promoted blooms of these ubiquitous algae over previous glacial cycles during deposition of iron-rich aerosols. Thus, the neurotoxin DA occurs both in coastal and oceanic waters, and its concentration, associated with changes in Pseudo-nitzschia abundance, likely varies naturally with climate cycles, as well as with artificial iron fertilization. Given that iron fertilization in iron-depleted regions of the sea has been proposed to enhance phytoplankton growth and, thereby, both reduce atmospheric CO(2) and moderate ocean acidification in surface waters, consideration of the potentially serious ecosystem impacts associated with DA is prudent.

Preparation of novel poly(vinyl alcohol)/SiO(2) composite nanofiber membranes with mesostructure and their application for removal of Cu(2+) from waste water.

PubMed

Wu, Shengju; Li, Fengting; Wu, Yinan; Xu, Ran; Li, Guangtao

2010-03-14

Novel mesoporous poly(vinyl alcohol)/SiO(2) composite nanofiber membranes functionalized with mercapto groups with diameters of 300-500 nm have been fabricated by a sol-gel electrospinning process; they were highly effective at absorbing Cu(ii) ions from waste water. These nanofiber membranes could be regenerated through acidification.

Do anaerobic digestates promote dispersion, acidification and water repellency in soils?

NASA Astrophysics Data System (ADS)

Voelkner, Amrei; Holthusen, Dörthe; Horn, Rainer

2014-05-01

Digestates are used as organic fertilizer on agricultural land due to their high amounts of nutrients (e.g. potassium, sodium). It is commonly expected that the application of sludge derived from anaerobic digestion can influence the soil structure and soil stability. Due to the fact that digestates contain large quantities of monovalent salts and long-chained fatty acids, the consequence of sludge amendment can be soil degradation caused by acidification, dispersion and increased water-repellency. Thus, water infiltration can be impeded which results in a preservation of stable soil aggregates. However, a diminished water infiltration can support water erosion and preferential flow of easy soluble nutrients into the groundwater. Our research was conducted with different digestates derived from maize, wheat and sugar beet to examine occurring processes in soils of two different textures after the application of anaerobic sludges. Particularly, we focused on the wetting properties of the soil. For this purpose, the wetting behavior was investigated by determining the sorptivity-based Repellency Index with moist samples and the contact angle with homogenized, air-dried soil material. Further surveys were carried out to assess the flow behavior of digestates application and the deformation of the particle-to-particle association by microscaled shearing. Additionally, the acidification process in the soil as a result of sludge application was investigated. To account for the dispersive impact of digestates, the turbidity of soil suspensions was ascertained. We summarize from the results that the digestates have a clear impact on the water repellency of the soil. We recognized a shift to more hydrophobic conditions. Partially, the pH remains on a high level due to the alkaline digestate, but several samples show a decline of pH, depending on the soil texture, respectively. However, soil structure was weakened as was shown by an increase of turbidity. As a conclusion, we point out the necessity to take into account the impact which anaerobic digestates might have on soil structure and stability in addition to their fertilizing effect to sustain the soil in a good state.

Water-quality data of soil water from three watersheds, Shenandoah National Park, Virginia, 1999-2000

USGS Publications Warehouse

Rice, Karen C.; Maben, Suzanne W.; Webb, James R.

2001-01-01

Data on the chemical composition of soil-water samples were collected quarterly from three watersheds in Shenandoah National Park, Virginia, from September 1999 through July 2000. The soil-water samples were analyzed for specific conductance and concentrations of sodium, potassium, calcium, magnesium, ammonium, chloride, nitrate, sulfate, acid-neutralizing capacity, silica, and total monomeric aluminum. The soil-water data presented in this report can be used to support water-quality modeling of the response of streams to episodic acidification. Laboratory analytical data as well as laboratory quality-assurance information also are presented.

Declining acidic deposition begins reversal of forest-soil acidification in the northeastern U.S. and eastern Canada

USGS Publications Warehouse

Lawrence, Gregory B.; Hazlett, Paul W.; Fernandez, Ivan J.; Ouimet, Rock; Bailey, Scott W.; Shortle, Walter C.; Smith, Kevin T.; Antidormi, Michael

2015-01-01

Decreasing trends in acidic deposition levels over the past several decades have led to partial chemical recovery of surface waters. However, depletion of soil Ca from acidic deposition has slowed surface water recovery and led to the impairment of both aquatic and terrestrial ecosystems. Nevertheless, documentation of acidic deposition effects on soils has been limited, and little is known regarding soil responses to ongoing acidic deposition decreases. In this study, resampling of soils in eastern Canada and the northeastern U.S. was done at 27 sites exposed to reductions in wet SO42– deposition of 5.7–76%, over intervals of 8–24 y. Decreases of exchangeable Al in the O horizon and increases in pH in the O and B horizons were seen at most sites. Among all sites, reductions in SO42– deposition were positively correlated with ratios (final sampling/initial sampling) of base saturation (P < 0.01) and negatively correlated with exchangeable Al ratios (P < 0.05) in the O horizon. However, base saturation in the B horizon decreased at one-third of the sites, with no increases. These results are unique in showing that the effects of acidic deposition on North American soils have begun to reverse.

Declining Acidic Deposition Begins Reversal of Forest-Soil Acidification in the Northeastern U.S. and Eastern Canada.

PubMed

Lawrence, Gregory B; Hazlett, Paul W; Fernandez, Ivan J; Ouimet, Rock; Bailey, Scott W; Shortle, Walter C; Smith, Kevin T; Antidormi, Michael R

2015-11-17

Decreasing trends in acidic deposition levels over the past several decades have led to partial chemical recovery of surface waters. However, depletion of soil Ca from acidic deposition has slowed surface water recovery and led to the impairment of both aquatic and terrestrial ecosystems. Nevertheless, documentation of acidic deposition effects on soils has been limited, and little is known regarding soil responses to ongoing acidic deposition decreases. In this study, resampling of soils in eastern Canada and the northeastern U.S. was done at 27 sites exposed to reductions in wet SO4(2-) deposition of 5.7-76%, over intervals of 8-24 y. Decreases of exchangeable Al in the O horizon and increases in pH in the O and B horizons were seen at most sites. Among all sites, reductions in SO4(2-) deposition were positively correlated with ratios (final sampling/initial sampling) of base saturation (P < 0.01) and negatively correlated with exchangeable Al ratios (P < 0.05) in the O horizon. However, base saturation in the B horizon decreased at one-third of the sites, with no increases. These results are unique in showing that the effects of acidic deposition on North American soils have begun to reverse.

Effects of near-future ocean acidification, fishing, and marine protection on a temperate coastal ecosystem.

PubMed

Cornwall, Christopher E; Eddy, Tyler D

2015-02-01

Understanding ecosystem responses to global and local anthropogenic impacts is paramount to predicting future ecosystem states. We used an ecosystem modeling approach to investigate the independent and cumulative effects of fishing, marine protection, and ocean acidification on a coastal ecosystem. To quantify the effects of ocean acidification at the ecosystem level, we used information from the peer-reviewed literature on the effects of ocean acidification. Using an Ecopath with Ecosim ecosystem model for the Wellington south coast, including the Taputeranga Marine Reserve (MR), New Zealand, we predicted ecosystem responses under 4 scenarios: ocean acidification + fishing; ocean acidification + MR (no fishing); no ocean acidification + fishing; no ocean acidification + MR for the year 2050. Fishing had a larger effect on trophic group biomasses and trophic structure than ocean acidification, whereas the effects of ocean acidification were only large in the absence of fishing. Mortality by fishing had large, negative effects on trophic group biomasses. These effects were similar regardless of the presence of ocean acidification. Ocean acidification was predicted to indirectly benefit certain species in the MR scenario. This was because lobster (Jasus edwardsii) only recovered to 58% of the MR biomass in the ocean acidification + MR scenario, a situation that benefited the trophic groups lobsters prey on. Most trophic groups responded antagonistically to the interactive effects of ocean acidification and marine protection (46%; reduced response); however, many groups responded synergistically (33%; amplified response). Conservation and fisheries management strategies need to account for the reduced recovery potential of some exploited species under ocean acidification, nonadditive interactions of multiple factors, and indirect responses of species to ocean acidification caused by declines in calcareous predators. © 2014 Society for Conservation Biology.

Carbon Dioxide Removal from Air using Seafloor Peridotite

NASA Astrophysics Data System (ADS)

Kelemen, P. B.; Brandt, A. R.; Benson, S. M.

2016-12-01

We describe a method for Carbon Dioxide Removal from Air (CDR) using CO2 uptake via mineral carbonation, about half the cost of that proposed by Kelemen & Matter [1,2]. Reaction of CO2-bearing fluids and gases with peridotite rapidly forms inert, non-toxic carbonate minerals. In proposed methods for combined capture and storage of ambient CO2 via reaction of seawater or ground water with peridotite [1-5], return of depleted water to the surface draws down CO2 from air. Because they use available chemical and thermal energy that drive spontaneous natural reactions, they may be the least expensive methods for capture of CO2 from air. We focus on subsurface CO2 uptake during flow of surface water through fractured peridotite. Previously [1-3], we envisioned a design similar to enhanced geothermal systems (EGS), involving two large diameter boreholes, subject to the challenges of achieving rapid, efficient return flow that limit the success of EGS. Recent discussions yielded a less expensive, more robust design: A single well produces ambient, CO2-depleted pore water from seafloor peridotite. Such water has low carbon and high pH [6,7,8]. Where such waters are delivered to the surface, observations reveal rapid CO2 uptake from air [1,3,8-10]. Delivery to the sea surface would also reduce local acidification. Thermal buoyancy and pumps powered by wave and tidal energy would bring warm formation water from wells to the surface through conduits surrounded by colder seawater. Recharge would be via flow in natural or enhanced fracture networks in unconfined submarine aquifers. This method could be tested and scaled-up in coastal, sub-seafloor peridotite with onshore drilling off Oman, New Caledonia and Papua New Guinea, Spain, Morocco, USA, etc. It is possible to achieve much larger scale. Giant volumes of peridotite are exposed on the seafloor along slow-spreading mid-ocean ridges [3]. Robotic drills could install wells that deliver CO2-depleted water through fabric tubes to the sea surface. Does anyone know James Cameron's phone number? [1] Kelemen & Matter PNAS 08 [2] Kelemen & Matter AGU Fall 14 [3] Kelemen et al AREPS 11 [4] Wilson et al IJGHGC 14 [5] Schuiling & Krijgsman Climate Change 06 [6] Barnes & O'Neil GSA Bull 69 [7] Kelley et al Science 01 [8] Paukert et al Chem Geol 12 [9] Mervine et al GCA 13 [10] Mervine et al Chem Geol 15

Calcification responses of symbiotic and aposymbiotic corals to near-future levels of ocean acidification

NASA Astrophysics Data System (ADS)

Ohki, S.; Irie, T.; Inoue, M.; Shinmen, K.; Kawahata, H.; Nakamura, T.; Kato, A.; Nojiri, Y.; Suzuki, A.; Sakai, K.; van Woesik, R.

2013-11-01

Increasing the acidity of ocean waters will directly threaten calcifying marine organisms such as reef-building scleractinian corals, and the myriad of species that rely on corals for protection and sustenance. Ocean pH has already decreased by around 0.1 pH units since the beginning of the industrial revolution, and is expected to decrease by another 0.2-0.4 pH units by 2100. This study mimicked the pre-industrial, present, and near-future levels of pCO2 using a precise control system (± 5% pCO2), to assess the impact of ocean acidification on the calcification of recently settled primary polyps of Acropora digitifera, both with and without symbionts, and adult fragments with symbionts. The increase in pCO2 of ~100 μatm between the pre-industrial period and the present had more effect on the calcification rate of adult A. digitifera than the anticipated future increases of several hundreds of micro-atmospheres of pCO2. The primary polyps with symbionts showed higher calcification rates than primary polyps without symbionts, suggesting that: (i) primary polyps housing symbionts are more tolerant to near-future ocean acidification than organisms without symbionts, and (ii) corals acquiring symbionts from the environment (i.e., broadcasting species) will be more vulnerable to ocean acidification than corals that maternally acquire symbionts.

Effects of hypoxia and ocean acidification on the upper thermal niche boundaries of coral reef fishes.

PubMed

Ern, Rasmus; Johansen, Jacob L; Rummer, Jodie L; Esbaugh, Andrew J

2017-07-01

Rising ocean temperatures are predicted to cause a poleward shift in the distribution of marine fishes occupying the extent of latitudes tolerable within their thermal range boundaries. A prevailing theory suggests that the upper thermal limits of fishes are constrained by hypoxia and ocean acidification. However, some eurythermal fish species do not conform to this theory, and maintain their upper thermal limits in hypoxia. Here we determine if the same is true for stenothermal species. In three coral reef fish species we tested the effect of hypoxia on upper thermal limits, measured as critical thermal maximum (CT max ). In one of these species we also quantified the effect of hypoxia on oxygen supply capacity, measured as aerobic scope (AS). In this species we also tested the effect of elevated CO 2 (simulated ocean acidification) on the hypoxia sensitivity of CT max We found that CT max was unaffected by progressive hypoxia down to approximately 35 mmHg, despite a substantial hypoxia-induced reduction in AS. Below approximately 35 mmHg, CT max declined sharply with water oxygen tension ( P w O 2 ). Furthermore, the hypoxia sensitivity of CT max was unaffected by elevated CO 2 Our findings show that moderate hypoxia and ocean acidification do not constrain the upper thermal limits of these tropical, stenothermal fishes. © 2017 The Author(s).

Differential response of two Mediterranean cold-water coral species to ocean acidification

NASA Astrophysics Data System (ADS)

Movilla, Juancho; Orejas, Covadonga; Calvo, Eva; Gori, Andrea; López-Sanz, Àngel; Grinyó, Jordi; Domínguez-Carrió, Carlos; Pelejero, Carles

2014-09-01

Cold-water coral (CWC) reefs constitute one of the most complex deep-sea habitats harboring a vast diversity of associated species. Like other tropical or temperate framework builders, these systems are facing an uncertain future due to several threats, such as global warming and ocean acidification. In the case of Mediterranean CWC communities, the effect may be exacerbated due to the greater capacity of these waters to absorb atmospheric CO2 compared to the global ocean. Calcification in these organisms is an energy-demanding process, and it is expected that energy requirements will be greater as seawater pH and the availability of carbonate ions decrease. Therefore, studies assessing the effect of a pH decrease in skeletal growth, and metabolic balance are critical to fully understand the potential responses of these organisms under a changing scenario. In this context, the present work aims to investigate the medium- to long-term effect of a low pH scenario on calcification and the biochemical composition of two CWCs from the Mediterranean, Dendrophyllia cornigera and Desmophyllum dianthus. After 314 d of exposure to acidified conditions, a significant decrease of 70 % was observed in Desmophyllum dianthus skeletal growth rate, while Dendrophyllia cornigera showed no differences between treatments. Instead, only subtle differences between treatments were observed in the organic matter amount, lipid content, skeletal microdensity, or porosity in both species, although due to the high variability of the results, these differences were not statistically significant. Our results also confirmed a heterogeneous effect of low pH on the skeletal growth rate of the organisms depending on their initial weight, suggesting that those specimens with high calcification rates may be the most susceptible to the negative effects of acidification.

Renal function in hepatosplenic schistosomiasis--an assessment of renal tubular disorders.

PubMed

Duarte, Daniella Bezerra; Vanderlei, Lucas Alexandre; Bispo, Raianne Kívia de Azevêdo; Pinheiro, Maria Eliete; da Silva, Geraldo Bezerra; Martins, Alice Maria Costa; Meneses, Gdayllon Cavalcante; Daher, Elizabeth De Francesco

2014-01-01

Renal involvement in Schistosoma mansoni infection is not well studied. The aim of this study is to investigate the occurrence of renal abnormalities in patients with hepatosplenic schistosomiasis (HSS), especially renal tubular disorders. This is a cross-sectional study with 20 consecutive patients with HSS followed in a medical center in Maceió, Alagoas, Brazil. Urinary acidification and concentration tests were performed using calcium chloride (CaCl2) after a 12-h period of water and food deprivation. The biomarker monocyte chemoattractant protein 1 (MCP-1) was quantified in urine. Fractional excretion of sodium (FENa+), transtubular potassium gradient (TTKG) and solute-free water reabsorption (TcH2O) were calculated. The HSS group was compared to a group of 17 healthy volunteers. Patients' mean age and gender were similar to controls. Urinary acidification deficit was found in 45% of HSS patients. Urinary osmolality was significantly lower in HSS patients (588 ± 112 vs. 764 ± 165 mOsm/kg, p = 0,001) after a 12-h period of water deprivation. TcH2O was lower in HSS patients (0.72 ± 0.5 vs. 1.1 ± 0.3, p = 0.04). Urinary concentration deficit was found in 85% of HSS patients. The values of MCP-1 were higher in HSS group than in control group (122 ± 134 vs. 40 ± 28 pg/mg-Cr, p = 0.01) and positively correlated with the values of microalbuminuria and proteinuria. HSS is associated with important kidney dysfunction. The main abnormalities found were urinary concentrating ability and incomplete distal acidification defect, demonstrating the occurrence of tubular dysfunction. There was also an increase in urinary MCP-1, which appears to be a more sensitive marker of renal damage than urinary albumin excretion rate.

Ocean acidification changes the structure of an Antarctic coastal protistan community

NASA Astrophysics Data System (ADS)

Hancock, Alyce M.; Davidson, Andrew T.; McKinlay, John; McMinn, Andrew; Schulz, Kai G.; van den Enden, Rick L.

2018-04-01

Antarctic near-shore waters are amongst the most sensitive in the world to ocean acidification. Microbes occupying these waters are critical drivers of ecosystem productivity, elemental cycling and ocean biogeochemistry, yet little is known about their sensitivity to ocean acidification. A six-level, dose-response experiment was conducted using 650 L incubation tanks (minicosms) adjusted to a gradient in fugacity of carbon dioxide (fCO2) from 343 to 1641 µatm. The six minicosms were filled with near-shore water from Prydz Bay, East Antarctica, and the protistan composition and abundance was determined by microscopy during 18 days of incubation. No CO2-related change in the protistan community composition was observed during the initial 8 day acclimation period under low light. Thereafter, the response of both autotrophic and heterotrophic protists to fCO2 was species-specific. The response of diatoms was mainly cell size related; microplanktonic diatoms ( > 20 µm) increased in abundance with low to moderate fCO2 (343-634 µatm) but decreased at fCO2 ≥ 953 µatm. Similarly, the abundance of Phaeocystis antarctica increased with increasing fCO2 peaking at 634 µatm. Above this threshold the abundance of micro-sized diatoms and P. antarctica fell dramatically, and nanoplanktonic diatoms ( ≤ 20 µm) dominated, therefore culminating in a significant change in the protistan community composition. Comparisons of these results with previous experiments conducted at this site show that the fCO2 thresholds are similar, despite seasonal and interannual differences in the physical and biotic environment. This suggests that near-shore microbial communities are likely to change significantly near the end of this century if anthropogenic CO2 release continues unabated, with profound ramifications for near-shore Antarctic ecosystem food webs and biogeochemical cycling.

Episodic acidification and changes in fish diversity in Pennsylvania headwater streams

USGS Publications Warehouse

Heard, R.M.; Sharpe, W.E.; Carline, R.F.; Kimmel, William G.

1997-01-01

Current water chemistry and fish communities in 70 Pennsylvania streams were compared with historical records to determine whether fish species richness had declined and, if so, the possible role of acidification. First-, second-, and third-order streams were selected, and stream sites sampled during the 1961-1971 survey were resampled during May and June 1994 in the Appalachian Plateaus province and during June 1995 in the Valley and Ridge province. Stream-flow was measured and a habitat assessment was completed at each site. Dominant bedrock types influencing the stream sampling site were determined for the Appalachian Plateaus streams. Episodic water chemistry was collected for 39 of the 50 Appalachian Plateaus streams and 14 of the 20 Valley and Ridge streams during the winter and spring of 1996. Thirty-eight (76%) streams of the Appalachian Plateaus province and 13 (65%) streams in the Valley and Ridge province had a loss of fish species since the 1961-1971 sampling period. Habitat scores were not related to losses of fish species. Of the 53 streams sampled during runoff episodes 22 (42%) increased in total dissolved aluminum by more than 50 ??g/L, and 31 (58%) streams decreased in pH by 0.5 units or more. Minnows (Cyprinidae) and darters (Percidae) are sensitive to acidity and were the species most often lost. Streams draining watersheds of the Appalachian Plateaus province dominated by Pottsville bedrock had more acidic water quality during base flow and storm flow sampling periods than streams dominated by Pocono bedrock. The results of this study indicate that many Pennsylvania streams have undergone an alarming reduction in fish diversity during the past 25-34 years. In many of these streams the loss in fish diversity may be attributed to episodic acidification.

Time series and recurrence interval models to predict the vulnerability of streams to episodic acidification in Shenandoah National Park, Virginia

USGS Publications Warehouse

Deviney, Frank A.; Rice, Karen C.; Hornberger, George M.

2006-01-01

Acid rain affects headwater streams by temporarily reducing the acid‐neutralizing capacity (ANC) of the water, a process termed episodic acidification. The increase in acidic components in stream water can have deleterious effects on the aquatic biota. Although acidic deposition is uniform across Shenandoah National Park (SNP) in north central Virginia, the stream water quality response during rain events varies substantially. This response is a function of the catchment's underlying geology and topography. Geologic and topographic data for SNP's 231 catchments are readily available; however, long‐term measurements (tens of years) of ANC and accompanying discharge are not and would be prohibitively expensive to collect. Transfer function time series models were developed to predict hourly ANC from discharge for five SNP catchments with long‐term water‐quality and discharge records. Hourly ANC predictions over short time periods (≤1 week) were averaged, and distributions of the recurrence intervals of annual water‐year minimum ANC values were model‐simulated for periods of 6, 24, 72, and 168 hours. The distributions were extrapolated to the rest of the SNP catchments on the basis of catchment geology and topography. On the basis of the models, large numbers of SNP streams have 6‐ to 168‐hour periods of low‐ANC values, which may stress resident fish populations. Smaller catchments are more vulnerable to episodic acidification than larger catchments underlain by the same bedrock. Catchments with similar topography and size are more vulnerable if underlain by less basaltic/carbonate bedrock. Many catchments are predicted to have successive years of low‐ANC values potentially sufficient to extirpate some species.

Environmental regulation of carbon isotope composition and crassulacean acid metabolism in three plant communities along a water availability gradient.

PubMed

Ricalde, M Fernanda; Andrade, José Luis; Durán, Rafael; Dupuy, Juan Manuel; Simá, J Luis; Us-Santamaría, Roberth; Santiago, Louis S

2010-12-01

Expression of crassulacean acid metabolism (CAM) is characterized by extreme variability within and between taxa and its sensitivity to environmental variation. In this study, we determined seasonal fluctuations in CAM photosynthesis with measurements of nocturnal tissue acidification and carbon isotopic composition (δ(13)C) of bulk tissue and extracted sugars in three plant communities along a precipitation gradient (500, 700, and 1,000 mm year(-1)) on the Yucatan Peninsula. We also related the degree of CAM to light habitat and relative abundance of species in the three sites. For all species, the greatest tissue acid accumulation occurred during the rainy season. In the 500 mm site, tissue acidification was greater for the species growing at 30% of daily total photon flux density (PFD) than species growing at 80% PFD. Whereas in the two wetter sites, the species growing at 80% total PFD had greater tissue acidification. All species had values of bulk tissue δ(13)C less negative than -20‰, indicating strong CAM activity. The bulk tissue δ(13)C values in plants from the 500 mm site were 2‰ less negative than in plants from the wetter sites, and the only species growing in the three communities, Acanthocereus tetragonus (Cactaceae), showed a significant negative relationship between both bulk tissue and sugar δ(13)C values and annual rainfall, consistent with greater CO(2) assimilation through the CAM pathway with decreasing water availability. Overall, variation in the use of CAM photosynthesis was related to water and light availability and CAM appeared to be more ecologically important in the tropical dry forests than in the coastal dune.

The effects of experimental lake acidification on the reproductive success of tree swallows

DOE Office of Scientific and Technical Information (OSTI.GOV)

St. Louis, V.L.

1992-01-01

The effects of lake acidification on reproductive success of tree swallows (Tachycineta bicolor) breeding near experimentally acidified and unmanipulated reference lakes at the Experimental Lake Area (ELA) were studied. Tree swallows are aerial insectivores that commonly breed near water and forage on emergent insects. Predictions suggest that avian food abundance and quality may be altered due to acidification. Breeding swallows foraged on chironomids emerging at their nest-site lakes before searching for food elsewhere. Among the calcium-rich items consumed by the swallows, fish bones were most numerous, followed by crayfish exoskeleton, clam shell, and bird eggshell. We found significantly fewer calcium-richmore » items in the stomachs of nestlings from acid lakes than in those from reference lakes. Chironomid species were significantly more abundant in acid lakes, while the Chironominae were less numerous. Biomass of emerging chironomids either increased significantly following acidification, or was not different from that of reference lakes. Concentrations of Al, Ca, Mn, and Zn were on average higher in chironomids from a number of the acid lakes than in chironomids from reference lakes. Calcium concentrations in chironomids from the most acid lake were significantly lower, suggesting that Ca may be difficult to sequester at low pH levels. Hepatic concentrations of metallothioneins in tree swallow nestlings were negatively correlated with pH of the nest-site lake. Additive concentrations of Cu and Zn in the liver were correlated with liver MT concentrations, but Cd was not. Near acidified lakes, eggs were smaller in certain dimensions, hatching success was lower, certain nestling body characters were smaller, nestling wing length was shorter, and growth functions were different than near unmanipulated reference lakes. Clearly even non-aquatic organisms are affected by acidification of freshwater ecosystems.« less

Optimising reef-scale CO2 removal by seaweed to buffer ocean acidification

NASA Astrophysics Data System (ADS)

Mongin, Mathieu; Baird, Mark E.; Hadley, Scott; Lenton, Andrew

2016-03-01

The equilibration of rising atmospheric {{CO}}2 with the ocean is lowering {pH} in tropical waters by about 0.01 every decade. Coral reefs and the ecosystems they support are regarded as one of the most vulnerable ecosystems to ocean acidification, threatening their long-term viability. In response to this threat, different strategies for buffering the impact of ocean acidification have been proposed. As the {pH} experienced by individual corals on a natural reef system depends on many processes over different time scales, the efficacy of these buffering strategies remains largely unknown. Here we assess the feasibility and potential efficacy of a reef-scale (a few kilometers) carbon removal strategy, through the addition of seaweed (fleshy multicellular algae) farms within the Great Barrier Reef at the Heron Island reef. First, using diagnostic time-dependent age tracers in a hydrodynamic model, we determine the optimal location and size of the seaweed farm. Secondly, we analytically calculate the optimal density of the seaweed and harvesting strategy, finding, for the seaweed growth parameters used, a biomass of 42 g N m-2 with a harvesting rate of up 3.2 g N m-2 d-1 maximises the carbon sequestration and removal. Numerical experiments show that an optimally located 1.9 km2 farm and optimally harvested seaweed (removing biomass above 42 g N m-2 every 7 d) increased aragonite saturation by 0.1 over 24 km2 of the Heron Island reef. Thus, the most effective seaweed farm can only delay the impacts of global ocean acidification at the reef scale by 7-21 years, depending on future global carbon emissions. Our results highlight that only a kilometer-scale farm can partially mitigate global ocean acidification for a particular reef.

Protein removal from waste brines generated during ham salting through acidification and centrifugation.

PubMed

Gutiérrez-Martínez, Maria del Rosario; Muñoz-Guerrero, Hernán; Alcaína-Miranda, Maria Isabel; Barat, José Manuel

2014-03-01

The salting step in food processes implies the production of large quantities of waste brines, having high organic load, high conductivity, and other pollutants with high oxygen demand. Direct disposal of the residual brine implies salinization of soil and eutrophication of water. Since most of the organic load of the waste brines comes from proteins leaked from the salted product, precipitation of dissolved proteins by acidification and removal by centrifugation is an operation to be used in waste brine cleaning. The aim of this study is optimizing the conditions for carrying out the separation of proteins from waste brines generated in the pork ham salting operation, by studying the influence of pH, centrifugal force, and centrifugation time. Models for determining the removal of proteins depending on the pH, centrifugal force, and time were obtained. The results showed a high efficacy of the proposed treatment for removing proteins, suggesting that this method could be used for waste brine protein removal. The best pH value to be used in an industrial process seems to be 3, while the obtained results indicate that almost 90% of the proteins from the brine can be removed by acidification followed by centrifugation. A further protein removal from the brine should have to be achieved using filtrating techniques, which efficiency could be highly improved as a consequence of the previous treatment through acidification and centrifugation. Waste brines from meat salting have high organic load and electrical conductivity. Proteins can be removed from the waste brine by acidification and centrifugation. The total protein removal can be up to 90% of the initial content of the waste brine. Protein removal is highly dependent on pH, centrifugation rate, and time. © 2014 Institute of Food Technologists®

A data-model synthesis to explain variability in calcification observed during a CO2 perturbation mesocosm experiment

NASA Astrophysics Data System (ADS)

Krishna, Shubham; Schartau, Markus

2017-04-01

The effect of ocean acidification on growth and calcification of the marine algae Emiliania huxleyi was investigated in a series of mesocosm experiments where enclosed water volumes that comprised a natural plankton community were exposed to different carbon dioxide (CO2) concentrations. Calcification rates observed during those experiments were found to be highly variable, even among replicate mesocosms that were subject to similar CO2 perturbations. Here, data from an ocean acidification mesocosm experiment are reanalysed with an optimality-based dynamical plankton model. According to our model approach, cellular calcite formation is sensitive to variations in CO2 at the organism level. We investigate the temporal changes and variability in observations, with a focus on resolving observed differences in total alkalinity and particulate inorganic carbon (PIC). We explore how much of the variability in the data can be explained by variations of the initial conditions and by the level of CO2 perturbation. Nine mesocosms of one experiment were sorted into three groups of high, medium, and low calcification rates and analysed separately. The spread of the three optimised ensemble model solutions captures most of the observed variability. Our results show that small variations in initial abundance of coccolithophores and the prevailing physiological acclimation states generate differences in calcification that are larger than those induced by ocean acidification. Accordingly, large deviations between optimal mass flux estimates of carbon and of nitrogen are identified even between mesocosms that were subject to similar ocean acidification conditions. With our model-based data analysis we document how an ocean acidification response signal in calcification can be disentangled from the observed variability in PIC.

Acidic deposition in the northeastern United States: Sources and inputs, ecosystem effects, and management strategies

USGS Publications Warehouse

Driscoll, C.T.; Lawrence, G.B.; Bulger, A.J.; Butler, T.J.; Cronan, C.S.; Eagar, C.; Lambert, K.F.; Likens, G.E.; Stoddard, J.L.; Weathers, K.C.

2001-01-01

North America and Europe are in the midst of a large-scale experiment. Sulfuric and nitric acids have acidified soils, lakes, and streams, thereby stressing or killing terrestrial and aquatic biota. It is therefore critical to measure and to understand the recovery of complex ecosystems in response to decreases in acidic deposition. Fortunately, the NADP, CASTNet, and AIRMoN-dry networks are in place to measure anticipated improvements in air quality and in atmospheric deposition. Unfortunately, networks to measure changes in water quality are sparse, and networks to monitor soil, vegetation, and fish responses are even more limited. There is an acute need to assess the response of these resources to decreases in acid loading. It would be particularly valuable to assess the recovery of aquatic biota - which respond directly to acid stress - to changes in surface water chemistry (Gunn and Mills 1998). We used long-term research from the HBEF and other sites across the northeastern United States to synthesize data on the effects of acidic deposition and to assess ecosystem responses to reductions in emissions. On the basis of existing data, it is clear that in the northeastern United States ??? reductions of SO2 emissions since 1970 have resulted in statistically significant decreases in SO42- in wet and bulk deposition and in surface waters ??? emissions of NOX and concentrations of NO3- in wet and bulk deposition and in surface waters have shown no increase or decrease since the 1980s ??? estimates of NH3 emissions are uncertain, although atmospheric deposition of NH4+ remains important for forest management and stream NO3- loss ??? acidic deposition has accelerated the leaching of base cations from soils, thus delaying the recovery of ANC in lakes and streams from decreased emissions of SO2 (at the HBEF the available soil Ca pool appears to have declined 50% over the past 50 years) ???sulfur and N from atmospheric deposition have accumulated in forest soils across the region, and the slow release of these stored elements from soil has delayed the recovery of lakes and streams after emissions have been reduced ??? acidic deposition has increased the concentration of toxic forms of Al in soil waters, lakes, and streams ??? acidic deposition has leached cellular Ca from red spruce foliage, which has made trees susceptible to freezing injury and led to more than 50% mortality of canopy trees in some areas of the Northeast ??? deficiencies of Ca2+ and Mg2+ have caused extensive mortality of sugar maple in Pennsylvania, and acidic deposition contributed to the depletion of these cations from soil ??? forty-one percent of lakes in the Adirondack Mountains and 15% of lakes in New England have exhibited chronic or episodic acidification or both; 83% of the affected lakes are acidic because of atmospheric deposition ??? the ANC of surface waters in New England has increased only modestly, and the Adirondack and Catskill regions have experienced no significant improvement, after decreases in atmospheric S deposition in recent decades ??? acidification of surface waters has resulted in a decrease in the survival, size, and density of fish and in the loss of fish and other aquatic biota from lakes and streams ??? emissions of air pollutants have important linkages to other large-scale environmental problems, including coastal eutrophication, mercury contamination, visibility impairment, climate change, and tropospheric ozone Moreover, we anticipate that recovery from acidic deposition will be a complex, two-phase process in which chemical recovery precedes biological recovery. The time for biological recovery is better defined for aquatic than for terrestrial ecosystems. For acid-affected aquatic ecosystems, we expect that stream populations of macroinvertebrates and lake populations of zooplankton will recover 3-10 years after favorable chemical conditions are reestablished; recovery of fish populations would follow. For terrestrial ecos

INTERACTIONS BETWEEN OCEAN ACIDIFICATION AND WARMING ON THE MORTALITY AND DISSOLUTION OF CORALLINE ALGAE(1).

PubMed

Diaz-Pulido, Guillermo; Anthony, Kenneth R N; Kline, David I; Dove, Sophie; Hoegh-Guldberg, Ove

2012-02-01

Coralline algae are among the most sensitive calcifying organisms to ocean acidification as a result of increased atmospheric carbon dioxide (pCO2 ). Little is known, however, about the combined impacts of increased pCO2 , ocean acidification, and sea surface temperature on tissue mortality and skeletal dissolution of coralline algae. To address this issue, we conducted factorial manipulative experiments of elevated CO2 and temperature and examined the consequences on tissue survival and skeletal dissolution of the crustose coralline alga (CCA) Porolithon (=Hydrolithon) onkodes (Heydr.) Foslie (Corallinaceae, Rhodophyta) on the southern Great Barrier Reef (GBR), Australia. We observed that warming amplified the negative effects of high pCO2 on the health of the algae: rates of advanced partial mortality of CCA increased from <1% to 9% under high CO2 (from 400 to 1,100 ppm) and exacerbated to 15% under warming conditions (from 26°C to 29°C). Furthermore, the effect of pCO2 on skeletal dissolution strongly depended on temperature. Dissolution of P. onkodes only occurred in the high-pCO2 treatment and was greater in the warm treatment. Enhanced skeletal dissolution was also associated with a significant increase in the abundance of endolithic algae. Our results demonstrate that P. onkodes is particularly sensitive to ocean acidification under warm conditions, suggesting that previous experiments focused on ocean acidification alone have underestimated the impact of future conditions on coralline algae. Given the central role that coralline algae play within coral reefs, these conclusions have serious ramifications for the integrity of coral-reef ecosystems. © 2011 Phycological Society of America.

Coral bleaching under unconventional scenarios of climate warming and ocean acidification

NASA Astrophysics Data System (ADS)

Kwiatkowski, Lester; Cox, Peter; Halloran, Paul R.; Mumby, Peter J.; Wiltshire, Andy J.

2015-08-01

Elevated sea surface temperatures have been shown to cause mass coral bleaching. Widespread bleaching, affecting >90% of global coral reefs and causing coral degradation, has been projected to occur by 2050 under all climate forcing pathways adopted by the IPCC for use within the Fifth Assessment Report. These pathways include an extremely ambitious pathway aimed to limit global mean temperature rise to 2 °C (ref. ; Representative Concentration Pathway 2.6--RCP2.6), which assumes full participation in emissions reductions by all countries, and even the possibility of negative emissions. The conclusions drawn from this body of work, which applied widely used algorithms to estimate coral bleaching, are that we must either accept that the loss of a large percentage of the world’s coral reefs is inevitable, or consider technological solutions to buy those reefs time until atmospheric CO2 concentrations can be reduced. Here we analyse the potential for geoengineering, through stratospheric aerosol-based solar radiation management (SRM), to reduce the extent of global coral bleaching relative to ambitious climate mitigation. Exploring the common criticism of geoengineering--that ocean acidification and its impacts will continue unabated--we focus on the sensitivity of results to the aragonite saturation state dependence of bleaching. We do not, however, address the additional detrimental impacts of ocean acidification on processes such as coral calcification that will further determine the benefit to corals of any SRM-based scenario. Despite the sensitivity of thermal bleaching thresholds to ocean acidification being uncertain, stabilizing radiative forcing at 2020 levels through SRM reduces the risk of global bleaching relative to RCP2.6 under all acidification-bleaching relationships analysed.

Impact of Ocean Acidification on Fluxes of non-CO2 Climate-Active Species: Report from the GESAMP WG38 workshop

NASA Astrophysics Data System (ADS)

Suntharalingam, Parvadha; Gehlen, Marion; Hopkins, Frances; Duce, Robert; Jickells, Tim; Gesamp WG38 Workshop, Participants

2017-04-01

Most investigations of the impact of ocean acidification (OA) have focused on changes in oceanic uptake of anthropogenic CO2, the resulting shifts in carbonate chemical equilibria, and the consequences for marine calcifying organisms. Little attention has been paid to the direct impacts of OA on the ocean sources of a range of other gaseous and aerosol species that are influential in regulating radiative forcing, atmospheric oxidising capacity and atmospheric chemistry. The oceanic processes governing emissions of these species are frequently sensitive to the changes in pH and ocean pCO2 accompanying ocean acidification. Such processes include, for example, metabolic rates of microbial activity, levels of surface primary production, ecosystem composition, and photo-chemical and microbially mediated production/loss pathways for individual species. The direct and indirect influences of these factors on oceanic fluxes of non-CO2 trace-gases and aerosols, and the subsequent feedbacks to climate remain highly uncertain. To address these issues UN/GESAMP Working Group 38, The Atmospheric Input of Chemicals to the Ocean, convened a workshop on this topic at the University of East Anglia in February, 2017. The goals of this workshop are to review and synthesize the current science on the direct impacts of ocean acidification on marine emissions to the atmosphere of key species important for climate, and atmospheric chemistry; and to identify the primary needs for new research to improve process understanding and to quantify the impact of ocean acidification on these marine fluxes (i.e., provide recommendations on the specific laboratory process studies, field measurements and model analyses needed to support targeted research activities on this topic). The results, conclusions, and recommendations of this workshop will be presented.

Inhibition of Na+−H+ exchange impairs receptor-mediated albumin endocytosis in renal proximal tubule-derived epithelial cells from opossum

PubMed Central

Gekle, Michael; Drumm, Karina; Mildenberger, Sigrid; Freudinger, Ruth; Gaßner, Birgit; Silbernagl, Stefan

1999-01-01

Receptor-mediated endocytosis is an important mechanism for transport of macromolecules and regulation of cell-surface receptor expression. In renal proximal tubules, receptor-mediated endocytosis mediates the reabsorption of filtered albumin. Acidification of the endocytic compartments is essential because it interferes with ligand-receptor dissociation, vesicle trafficking, fusion events and coat formation. Here we show that the activity of Na+−H+ exchanger isoform 3 (NHE3) is important for proper receptor-mediated endocytosis of albumin and endosomal pH homeostasis in a renal proximal tubular cell line (opossum kidney cells) which expresses NHE3 only. Depending on their inhibitory potency with respect to NHE3 and their lipophilicity, the NHE inhibitors EIPA, amiloride and HOE694 differentially reduced albumin endocytosis. The hydrophilic inhibitor HOE642 had no effect. Inhibition of NHE3 led to an alkalinization of early endosomes and to an acidification of the cytoplasm, indicating that Na+−H+ exchange contributes to the acidification of the early endosomal compartment due to the existence of a sufficient Na+ gradient across the endosomal membrane. Exclusive acidification of the cytoplasm with propionic acid or by removal of Na+ induced a significantly smaller reduction in endocytosis than that induced by inhibition of Na+−H+ exchange. Analysis of the inhibitory profiles indicates that in early endosomes and endocytic vesicles NHE3 is of major importance, whereas plasma membrane NHE3 plays a minor role. Thus, NHE3-mediated acidification along the first part of the endocytic pathway plays an important role in receptor-mediated endocytosis. Furthermore, the involvement of NHE3 offers new ways to explain the regulation of receptor-mediated endocytosis. PMID:10545138

Electrical characterization of single cells using polysilicon wire ion sensor in an isolation window.

PubMed

Wu, You-Lin; Hsu, Po-Yen; Hsu, Chung-Ping; Wang, Chih-Cheng; Lee, Li-Wen; Lin, Jing-Jenn

2011-10-01

A polysilicon wire (PSW) sensor can detect the H(+) ion density (pH value) of the medium coated on its surface, and different cells produce different extracellular acidification and hence different H(+) ion densities. Based on this, we used a PSW sensor in combination with a mold-cast polydimethylsiloxane (PDMS) isolation window to detect the adhesion, apoptosis and extracellular acidification of single normal cells and single cancer cells. Single living human normal cells WI38, MRC5, and BEAS-2B as well as non-small-cell lung cancer (NSCLC) cells A549, H1299, and CH27 were cultivated separately inside the isolation window. The current flowing through the PSW channel was measured. From the PSW channel current change as a function of time, we determined the cell adhesion time by observing the time required for the current change to saturate, since a stable extracellular ion density was established after the cells were completely adhered to the PSW surface. The apoptosis of cells can also be determined when the channel current change drops to zero. We found that all the NSCLC cells had a higher channel current change and hence a lower pH value than the normal cells anytime after they were seeded. The corresponding average pH values were 5.86 for A549, 6.00 for H1299, 6.20 for CH27, 6.90 for BEAS-2B, 6.96for MRC5, and 7.02 for WI38, respectively, after the cells were completely adhered to the PSW surface. Our results show that NSCLC cells have a stronger cell-substrate adhesion and a higher extracellular acidification rate than normal cells.

Early indications of soil recovery from acidic deposition in U.S. red spruce forests

USGS Publications Warehouse

Lawrence, Gregory B.; Shortle, Walter C.; David, Mark B.; Smith, Kevin T.; Warby, Richard A.F.; Lapenis, Andrei G.

2012-01-01

Forty to fifty percent decreases in acidic deposition through the 1980s and 1990s led to partial recovery of acidified surface waters in the northeastern United States; however, the limited number of studies that have assessed soil change found increased soil acidification during this period. From existing data, it's not clear whether soils continued to worsen in the 1990s or if recovery had begun. To evaluate possible changes in soils through the 1990s, soils in six red spruce (Picea rubens Sarg.) stands in New York, Vermont, New Hampshire, and Maine, first sampled in 1992 to 1993, were resampled in 2003 to 2004. The Oa-horizon pH increased (P 42−, which decreased the mobility of Al throughout the upper soil profile. Results indicate a nascent recovery driven largely by vegetation processes.

Drivers of Water Column Calcium Carbonate Fluxes and Dissolution in the Gulf of Maine: Impacts on the Carbon Cycle

NASA Astrophysics Data System (ADS)

Pilskaln, C. H.; Wang, A. Z.; Lawson, G. L.; Hayashi, K.; Salisbury, J.

2016-02-01

Recent studies indicate that the U.S. Northeast coastal region, particularly the Gulf of Maine (GoME), may be more susceptible to ocean acidification (OA) than previously thought due to the low buffer capacity, low pH, and low calcium carbonate saturation measured in the region. In particular, sub-surface waters of the GoME already experience under-saturation with respect to aragonite in spring and summer and recent data suggest that water-column aragonite dissolution may occur throughout the year, even when aragonite is slightly over-saturated. This dissolution process appears associated with organic carbon remineralization in the extensive benthic nepheloid layers and may thus represent a major control over the calcium carbonate (CaCO3) budget of deep, near-bottom waters of the GoME. These findings are surprising for shallow, non-upwelling shelf systems and have important implications for the CaCO3 cycle, shell-building organisms, and the GoME planktonic ecosystem. Additionally, freshening of the GoME over the past several decades due to an increase in low-salinity water input originating in the Labrador Sea may further decrease seawater pH and aragonite saturation in the gulf. We present a variety of biogeochemical data that suggest linkages between potential water column CaCO3 dissolution and their impacts on the GoME carbon cycle.

Limacina retroversa's response to combined effects of ocean acidification and sea water freshening

NASA Astrophysics Data System (ADS)

Manno, C.; Morata, N.; Primicerio, R.

2012-11-01

Anthropogenic carbon dioxide emissions induce ocean acidification, thereby reducing carbonate ion concentration, which may affect the ability of calcifying organisms to build shells. Pteropods, the main planktonic producers of aragonite in the worlds' oceans, may be particularly vulnerable to changes in sea water chemistry. The negative effects are expected to be most severe at high-latitudes, where natural carbonate ion concentrations are low. In this study we investigated the combined effects of ocean acidification and freshening on Limacina retroversa, the dominant pteropod in sub polar areas. Living L. retroversa, collected in Northern Norwegian Sea, were exposed to four different pH values ranging from the pre-industrial level to the forecasted end of century ocean acidification scenario. Since over the past half-century the Norwegian Sea has experienced a progressive freshening with time, each pH level was combined with a salinity gradient in two factorial, randomized experiments investigating shell degradation, swimming behavior and survival. In addition, to investigate shell degradation without any physiologic influence, one perturbation experiments using only shells of dead pteropods was performed. Lower pH reduced shell mass whereas shell dissolution increased with pCO2. Interestingly, shells of dead organisms had a higher degree of dissolution than shells of living individuals. Mortality of Limacina retroversa was strongly affected only when both pH and salinity reduced simultaneously. The combined effects of lower salinity and lower pH also affected negatively the ability of pteropods to swim upwards. Results suggest that the energy cost of maintaining ion balance and avoiding sinking (in low salinity scenario) combined with the extra energy cost necessary to counteract shell dissolution (in high pCO2 scenario), exceed the available energy budget of this organism causing the pteropods to change swimming behavior and begin to collapse. Since L. retroversa play an important role in the transport of carbonates to the deep oceans these findings have significant implications for the mechanisms influencing the inorganic carbon cycle in the sub-polar area.

Tillamook Estuary Case Study: Local Drivers Influencing Coastal Acidification

EPA Science Inventory

US EPA initiated a study in the Tillamook estuary and watershed focused on the impact of changes in watershed land use, ocean conditions, and weather on estuarine water quality and ecosystem goods and services production within the estuary. This project is a collaboration betwee...

Influence of predicted climage change elements on Z. japonica distribution in Washington State

EPA Science Inventory

Global climate change (GCC) is expected to have pronounced impacts on estuarine and marine habitats including sea level rise, increased storm intensity, increased air and water temperatures, changes in upwelling dynamics and ocean acidification. All of these elements are likely ...

Climate Change and the Department of Defense: An Introduction

DTIC Science & Technology

2016-10-24

decreasing Arctic ice cover, type, and thickness leads to increased tourism , greater resource extraction, and greater thawing permafrost. In turn, this great...level rise, ocean acidification, and water warming pose to fish stocks, coral, mangroves, recreation and tourism , and the control of disease

PRESERVATION OF SULFIDIC WATERS CONTAINING DISSOLVED AS (III)

EPA Science Inventory

Field samples for arsenic analyses are commonly preserved by acidification with hydrochloric or nitric acid. In some suboxic samples, appreciable concentrations of H2S and HS- are observed due to the microbial respiration of sulfate-reducing bacteria. If both As(III) and sulfid...

Robustness of larval development of intertidal sea urchin species to simulated ocean warming and acidification.

PubMed

García, Eliseba; Hernández, José Carlos; Clemente, Sabrina

2018-08-01

Ocean warming and acidification are the two most significant side effects of carbone dioxide emissions in the world's oceans. By changing water, temperature and pH are the main environmental factors controlling the distribution, physiology, morphology and behaviour of marine invertebrates. This study evaluated the combined effects of predicted high temperature levels, and predicted low pH values, on fertilization and early development stages of the sea urchins Arbacia lixula, Paracentrotus lividus, Sphaerechinus granularis and Diadema africanum. Twelve treatments, combining different temperatures (19, 21, 23 and 25 °C) and pH values (8.1, 7.7 and 7.4 units), were tested in laboratory experiments. All of the tested temperatures and pH values were within the open coast seawater range expected within the next century. We examined fertilization rate, cleavage rate, 3-day larvae survival, and development of the different sea urchin species at set time intervals after insemination. Our results highlight the susceptibility of subtidal species to environmental changes, and the robustness of intertidal species to ocean warming and acidification. Copyright © 2018 Elsevier Ltd. All rights reserved.

Mountain lakes of Russian subarctic as markers of air pollution: Acidification, metals and paleoecology

DOE Office of Scientific and Technical Information (OSTI.GOV)

Moiseenko, T.I.; Dauvalter, V.A.; Kagan, L.Y.

1996-12-31

The Kola Peninsula mountain lakes reflect a real situation not only of the local air pollution but also polluted transborder emissions from Europe to Arctic and they are of interest for early detection and monitoring for acidification and pollution by heavy metals. Two monitoring mountain lakes had a discrepancy by their resistance to acidification: the Chuna lake is vulnerable and the Chibiny one is not, respectively. Despite the Chuna and Chibiny lakes are close tone of the main heavy metal pollution sources of the Kola Peninsula - smelters of the Severonickel Company, local emissions very slightly affect the mountain lakes,more » because heavily polluted air masses do not rise in altitude. Sulfur deposition on the Chuna lake catchment is 0.4 gSm{sup -2}, Chibiny lake is 0.6 gSm{sup -2}. In comparison with area at the foot of the mountain (less than 200 m above the sea level) sulfur deposition is 1.0-1.5 gSm{sup -2}. Water quality, sediment chemistry, and diatoms in sediment cores were studied.« less

Future habitat suitability for coral reef ecosystems under global warming and ocean acidification

PubMed Central

Couce, Elena; Ridgwell, Andy; Hendy, Erica J

2013-01-01

Rising atmospheric CO2 concentrations are placing spatially divergent stresses on the world's tropical coral reefs through increasing ocean surface temperatures and ocean acidification. We show how these two stressors combine to alter the global habitat suitability for shallow coral reef ecosystems, using statistical Bioclimatic Envelope Models rather than basing projections on any a priori assumptions of physiological tolerances or fixed thresholds. We apply two different modeling approaches (Maximum Entropy and Boosted Regression Trees) with two levels of complexity (one a simplified and reduced environmental variable version of the other). Our models project a marked temperature-driven decline in habitat suitability for many of the most significant and bio-diverse tropical coral regions, particularly in the central Indo-Pacific. This is accompanied by a temperature-driven poleward range expansion of favorable conditions accelerating up to 40–70 km per decade by 2070. We find that ocean acidification is less influential for determining future habitat suitability than warming, and its deleterious effects are centered evenly in both hemispheres between 5° and 20° latitude. Contrary to expectations, the combined impact of ocean surface temperature rise and acidification leads to little, if any, degradation in future habitat suitability across much of the Atlantic and areas currently considered ‘marginal’ for tropical corals, such as the eastern Equatorial Pacific. These results are consistent with fossil evidence of range expansions during past warm periods. In addition, the simplified models are particularly sensitive to short-term temperature variations and their projections correlate well with reported locations of bleaching events. Our approach offers new insights into the relative impact of two global environmental pressures associated with rising atmospheric CO2 on potential future habitats, but greater understanding of past and current controls on coral reef ecosystems is essential to their conservation and management under a changing climate. PMID:23893550

Future habitat suitability for coral reef ecosystems under global warming and ocean acidification.

PubMed

Couce, Elena; Ridgwell, Andy; Hendy, Erica J

2013-12-01

Rising atmospheric CO2 concentrations are placing spatially divergent stresses on the world's tropical coral reefs through increasing ocean surface temperatures and ocean acidification. We show how these two stressors combine to alter the global habitat suitability for shallow coral reef ecosystems, using statistical Bioclimatic Envelope Models rather than basing projections on any a priori assumptions of physiological tolerances or fixed thresholds. We apply two different modeling approaches (Maximum Entropy and Boosted Regression Trees) with two levels of complexity (one a simplified and reduced environmental variable version of the other). Our models project a marked temperature-driven decline in habitat suitability for many of the most significant and bio-diverse tropical coral regions, particularly in the central Indo-Pacific. This is accompanied by a temperature-driven poleward range expansion of favorable conditions accelerating up to 40-70 km per decade by 2070. We find that ocean acidification is less influential for determining future habitat suitability than warming, and its deleterious effects are centered evenly in both hemispheres between 5° and 20° latitude. Contrary to expectations, the combined impact of ocean surface temperature rise and acidification leads to little, if any, degradation in future habitat suitability across much of the Atlantic and areas currently considered 'marginal' for tropical corals, such as the eastern Equatorial Pacific. These results are consistent with fossil evidence of range expansions during past warm periods. In addition, the simplified models are particularly sensitive to short-term temperature variations and their projections correlate well with reported locations of bleaching events. Our approach offers new insights into the relative impact of two global environmental pressures associated with rising atmospheric CO2 on potential future habitats, but greater understanding of past and current controls on coral reef ecosystems is essential to their conservation and management under a changing climate. © 2013 John Wiley & Sons Ltd.

V-ATPase-dependent luminal acidification is required for endocytic recycling of a yeast cell wall stress sensor, Wsc1p

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ueno, Kazuma; Saito, Mayu; Nagashima, Makiko

Highlights: •A targeted genome screen identified 5 gene groups affecting Wsc1p recycling. •V-ATPase-dependent luminal acidification is required for Wsc1p recycling. •Activity of V-ATPase might be required for cargo recognition by the retromer complex. -- Abstract: Wsc1p is a major cell wall sensor protein localized at the polarized cell surface. The localization of Wsc1p is maintained by endocytosis and recycling from endosomes back to the cell surface, but changes to the vacuole when cells are subjected to heat stress. Exploiting this unique property of Wsc1p, we screened for yeast single-gene deletion mutants exhibiting defects in Wsc1p trafficking. By expressing 3GFP-tagged Wsc1pmore » in mutants with deleted genes whose function is related to intracellular trafficking, we identified 5 gene groups affecting Wsc1p trafficking, impaired respectively in endocytic internalization, multivesicular body sorting, the GARP complex, endosomal maturation/vacuolar fusion, and V-ATPase. Interestingly, deletion of the VPH1 gene, encoding the V{sub o} subunit of vacuolar-type H{sup +}-ATPase (V-ATPase), led to mis-localization of Wsc1p from the plasma membrane to the vacuole. In addition, disruption of other V-ATPase subunits (vma mutants) also caused defects of Wsc1p trafficking and vacuolar acidification similar to those seen in the vph1Δ mutant. Moreover, we found that deletion of the VPS26 gene, encoding a subunit of the retromer complex, also caused a defect in Wsc1p recycling and mis-localization of Wsc1p to the vacuole. These findings clarified the previously unidentified Wsc1p recycling pathway and requirement of V-ATPase-dependent luminal acidification for Wsc1p recycling.« less

Reduced calcification and lack of acclimatization by coral colonies growing in areas of persistent natural acidification.

PubMed

Crook, Elizabeth D; Cohen, Anne L; Rebolledo-Vieyra, Mario; Hernandez, Laura; Paytan, Adina

2013-07-02

As the surface ocean equilibrates with rising atmospheric CO2, the pH of surface seawater is decreasing with potentially negative impacts on coral calcification. A critical question is whether corals will be able to adapt or acclimate to these changes in seawater chemistry. We use high precision CT scanning of skeletal cores of Porites astreoides, an important Caribbean reef-building coral, to show that calcification rates decrease significantly along a natural gradient in pH and aragonite saturation (Ωarag). This decrease is accompanied by an increase in skeletal erosion and predation by boring organisms. The degree of sensitivity to reduced Ωarag measured on our field corals is consistent with that exhibited by the same species in laboratory CO2 manipulation experiments. We conclude that the Porites corals at our field site were not able to acclimatize enough to prevent the impacts of local ocean acidification on their skeletal growth and development, despite spending their entire lifespan in low pH, low Ωarag seawater.

Smog Nitrogen and the Rapid Acidification of Forest Soil, San Bernardino Mountains, Southern California

PubMed Central

Wood, Yvonne A.; Fenn, Mark; Meixner, Thomas; Shouse, Peter J.; Breiner, Joan; Allen, Edith; Wu, Laosheng

2007-01-01

We report the rapid acidification of forest soils in the San Bernardino Mountains of southern California. After 30 years, soil to a depth of 25 cm has decreased from a pH (measured in 0.01 M CaCl2) of 4.8 to 3.1. At the 50-cm depth, it has changed from a pH of 4.8 to 4.2. We attribute this rapid change in soil reactivity to very high rates of anthropogenic atmospheric nitrogen (N) added to the soil surface (72 kg ha–1 year–1) from wet, dry, and fog deposition under a Mediterranean climate. Our research suggests that a soil textural discontinuity, related to a buried ancient landsurface, contributes to this rapid acidification by controlling the spatial and temporal movement of precipitation into the landsurface. As a result, the depth to which dissolved anthropogenic N as nitrate (NO3) is leached early in the winter wet season is limited to within the top ~130 cm of soil where it accumulates and increases soil acidity. PMID:17450295

Evaluation of h secretion relative to zeatin-induced growth of detached cucumber cotyledons.

PubMed

Ross, C W; Rayle, D L

1982-11-01

Cytokinins promote expansion of cotyledons detached from seedlings of more than a dozen species. The zeatin-enhanced expansion of cucumber (Cucumis sativus L. cv Marketer) cotyledons was investigated. In addition, whether acid secretion is involved in wall loosening accompanying such accelerated growth was evaluated. For cotyledons abraded with carborundum or cut into either eight or 18 pieces, we detected no zeatin-enhanced acidification of the growth medium during growth periods of 3 days. Measurements of pH values on each surface of zeatin-treated, abraded cotyledons after 3 days of growth also showed no detectable acidification caused by the hormone. Furthermore, with several buffers at pH values ranging from 5 to 8, growth of nonabraded, abraded, or cut cotyledons with or without zeatin was independent of external pH. However, experiments restricted to about 12 hours indicated that certain acidic buffers enhanced growth of cotyledons cut into 18 pieces. Lastly, concentrations of fusicoccin that caused growth promotion equal to that of zeatin initiated substantial acidification of the medium. Collectively, these data suggest that zeatin-induced expansion of detached cucumber cotyledons is independent of H(+) secretion.

Osmoregulation in Lilium Pollen Grains Occurs via Modulation of the Plasma Membrane H+ ATPase Activity by 14-3-3 Proteins1[C][W][OA

PubMed Central

Pertl, Heidi; Pöckl, Magdalena; Blaschke, Christian; Obermeyer, Gerhard

2010-01-01

To allow successful germination and growth of a pollen tube, mature and dehydrated pollen grains (PGs) take up water and have to adjust their turgor pressure according to the water potential of the surrounding stigma surface. The turgor pressure of PGs of lily (Lilium longiflorum) was measured with a modified pressure probe for simultaneous recordings of turgor pressure and membrane potential to investigate the relation between water and electrogenic ion transport in osmoregulation. Upon hyperosmolar shock, the turgor pressure decreased, and the plasma membrane (PM) hyperpolarizes in parallel, whereas depolarization of the PM was observed with hypoosmolar treatment. An acidification and alkalinization of the external medium was monitored after hyper- and hypoosmotic treatments, respectively, and pH changes were blocked by vanadate, indicating a putative role of the PM H+ ATPase. Indeed, an increase in PM-associated 14-3-3 proteins and an increase in PM H+ ATPase activity were detected in PGs challenged by hyperosmolar medium. We therefore suggest that in PGs the PM H+ ATPase via modulation of its activity by 14-3-3 proteins is involved in the regulation of turgor pressure. PMID:20974894

Environmental Protection: Federal Incentives Could Help Promote Land Use That Protects Air and Water Quality

DTIC Science & Technology

2001-10-01

can over stimulate algae and plant growth, which can degrade coral reefs and important fish spawning habitats. In 2001, the U.S. Geological Survey... Oceanic and Atmospheric Administration NPDES National Pollutant Discharge Elimination System PAH polycyclic aromatic hydrocarbons SIP state...as a significant cause of coastal water quality problems, the acidification of streams and lakes, and the toxic contamination of fish and the birds

Effects of ocean acidification on salinity tolerance and seawater growth of Atlantic salmon Salmo salar smolts.

PubMed

Mccormick, S D; Regish, A M

2018-06-23

Human activity has resulted in increasing atmospheric carbon dioxide (CO 2 ), which will result in reduced pH and higher levels of CO 2 in the ocean, a process known as ocean acidification. Understanding the effects of ocean acidification (OA) on fishes will be important to predicting and mitigating its consequences. Anadromous species such as salmonids may be especially at risk because of their rapid movements between fresh water and seawater, which could minimize their ability to acclimate. In the present study, we examine the effect of future OA on the salinity tolerance and early seawater growth of Atlantic salmon Salmo salar smolts. Exposure to 61.81 Pa and 102.34 Pa CO 2 did not alter salinity tolerance but did result in slightly lower plasma chloride levels in smolts exposed to seawater compared with controls (39.59 Pa). Gill Na + -K + -ATPase activity, plasma cortisol, glucose and haematocrit after seawater exposure were not altered by elevated CO 2 . Growth rate in the first 2 weeks of seawater exposure was greater at 102.34 Pa CO 2 than under control conditions. This study of the effects of OA on S. salar during the transition from fresh water to seawater indicates that elevated CO 2 is not likely to affect osmoregulation negatively and may improve early growth in seawater. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

LiveOcean: A Daily Forecast Model of Ocean Acidification for Shellfish Growers

NASA Astrophysics Data System (ADS)

MacCready, P.; Siedlecki, S. A.; McCabe, R. M.

2016-12-01

The coastal estuaries of the NE Pacific host a highly productive shellfish industry, but in the past decade they have suffered from many years in which no natural set of oysters occurred. It appears that coastal waters with low Aragonite saturation state may be the cause. This "acidified" water is the result of (i) upwelling of NE Pacific water from near the shelf break that is already low in pH, and (ii) further acidification of that water by productivity and remineralization on the shelf, and (iii) increasing atmospheric CO2. As part of a coordinated research response to this issue, we have developed the LiveOcean modeling system, which creates daily three-day forecasts of circulation and biogeochemical properties in Oregon-Washington-British Columbia coastal and estuarine waters. The system includes realistic tides, atmospheric forcing (from a regional WRF model), ocean boundary conditions (from HYCOM), and rivers (from USGS and Environment Canada). The model is also used for Harmful Algal Bloom prediction. There has been extensive validation of hindcast runs for currents and hydrography, and more limited validation of biogeochemical variables. Model results are pushed daily to the cloud, and made available to the public through the NANOOS Visualization System (NVS). NVS also includes automated model-data comparisons with real-time NDBC and OOI moorings. Future work will focus on optimizing the utility of this system for regional shellfish growers.

Simulation of future stream alkalinity under changing deposition and climate scenarios.

PubMed

Welsch, Daniel L; Cosby, B Jack; Hornberger, George M

2006-08-31

Models of soil and stream water acidification have typically been applied under scenarios of changing acidic deposition, however, climate change is usually ignored. Soil air CO2 concentrations have potential to increase as climate warms and becomes wetter, thus affecting soil and stream water chemistry by initially increasing stream alkalinity at the expense of reducing base saturation levels on soil exchange sites. We simulate this change by applying a series of physically based coupled models capable of predicting soil air CO2 and stream water chemistry. We predict daily stream water alkalinity for a small catchment in the Virginia Blue Ridge for 60 years into the future given stochastically generated daily climate values. This is done for nine different combinations of climate and deposition. The scenarios for both climate and deposition include a static scenario, a scenario of gradual change, and a scenario of abrupt change. We find that stream water alkalinity continues to decline for all scenarios (average decrease of 14.4 microeq L-1) except where climate is gradually warming and becoming more moist (average increase of 13 microeq L-1). In all other scenarios, base cation removal from catchment soils is responsible for limited alkalinity increase resulting from climate change. This has implications given the extent that acidification models are used to establish policy and legislation concerning deposition and emissions.

An On-Line Solid Phase Extraction-Liquid Chromatography-Tandem Mass Spectrometry Method for the Determination of Perfluoroalkyl Acids in Drinking and Surface Waters

PubMed Central

Mazzoni, Michela; Rusconi, Marianna; Valsecchi, Sara; Martins, Claudia P. B.; Polesello, Stefano

2015-01-01

An UHPLC-MS/MS multiresidue method based on an on-line solid phase extraction (SPE) procedure was developed for the simultaneous determination of 9 perfluorinated carboxylates (from 4 to 12 carbon atoms) and 3 perfluorinated sulphonates (from 4 to 8 carbon atoms). This work proposes using an on-line solid phase extraction before chromatographic separation and analysis to replace traditional methods of off-line SPE before direct injection to LC-MS/MS. Manual sample preparation was reduced to sample centrifugation and acidification, thus eliminating several procedural errors and significantly reducing time-consuming and costs. Ionization suppression between target perfluorinated analytes and their coeluting SIL-IS were detected for homologues with a number of carbon atoms less than 9, but the quantitation was not affected. Total matrix effect corrected by SIL-IS, inclusive of extraction efficacy, and of ionization efficiency, ranged between −34 and +39%. The percentage of recoveries, between 76 and 134%, calculated in different matrices (tap water and rivers impacted by different pollutions) was generally satisfactory. LODs and LOQs of this on-line SPE method, which also incorporate recovery losses, ranged from 0.2 to 5.0 ng/L and from 1 to 20 ng/L, respectively. Validated on-line SPE-LC/MS/MS method has been applied in a wide survey for the determination of perfluoroalkyl acids in Italian surface and ground waters. PMID:25834752

Natural Weathering Rates of Silicate Minerals

NASA Astrophysics Data System (ADS)

White, A. F.

2003-12-01

Silicates constitute more than 90% of the rocks exposed at Earth's land surface (Garrels and Mackenzie, 1971). Most primary minerals comprising these rocks are thermodynamically unstable at surface pressure/temperature conditions and are therefore susceptible to chemical weathering. Such weathering has long been of interest in the natural sciences. Hartt (1853) correctly attributed chemical weathering to "the efficacy of water containing carbonic acid in promoting the decomposition of igneous rocks." Antecedent to the recent interest in the role of vegetation on chemical weathering, Belt (1874) observed that the most intense weathering of rocks in tropical Nicaragua was confined to forested regions. He attributed this effect to "the percolation through rocks of rain water charged with a little acid from decomposing vegetation." Chamberlin (1899) proposed that the enhanced rates of chemical weathering associated with major mountain building episodes in Earth's history resulted in a drawdown of atmospheric CO2 that led to periods of global cooling. Many of the major characteristics of chemical weathering had been described when Merrill (1906) published the groundbreaking volume Rocks, Rock Weathering, and Soils.The major advances since that time, particularly during the last several decades, have centered on understanding the fundamental chemical, hydrologic, and biologic processes that control weathering and in establishing quantitative weathering rates. This research has been driven by the importance of chemical weathering to a number environmentally and economically important issues. Undoubtedly, the most significant aspect of chemical weathering is the breakdown of rocks to form soils, a process that makes life possible on the surface of the Earth. The availability of many soil macronutrients such as magnesium, calcium, potassium, and PO4 is directly related to the rate at which primary minerals weather. Often such nutrient balances are upset by anthropogenic activities. For example, Huntington et al. (2000) show that extensive timber harvesting in the southeastern forests of the United States, which are underlain by intensely weathered saprolites, produces net calcium exports that exceed inputs from weathering, thus creating a long-term regional problem in forest management.The role of chemical weathering has long been recognized in economic geology. Tropical bauxites, which account for most of world's aluminum ores, are typical examples of residual concentration of silicate rocks by chemical weathering over long time periods (Samma, 1986). Weathering of ultramafic silicates such as peridotites forms residual lateritic deposits that contain significant deposits of nickel and cobalt. Ores generated by chemical mobilization include uranium deposits that are produced by weathering of granitic rocks under oxic conditions and subsequent concentration by sorption and precipitation ( Misra, 2000).Over the last several decades, estimating rates of silicate weathering has become important in addressing new environmental issues. Acidification of soils, rivers, and lakes has become a major concern in many parts of North America and Europe. Areas at particular risk are uplands where silicate bedrock, resistant to chemical weathering, is overlain by thin organic-rich soils (Driscoll et al., 1989). Although atmospheric deposition is the most important factor in watershed acidification, land use practices, such as conifer reforestation, also create acidification problems ( Farley and Werritty, 1989). In such environments, silicate hydrolysis reactions are the principal buffer against acidification. As pointed out by Drever and Clow (1995), a reasonable environmental objective is to decrease the inputs of acidity such that they are equal to or less than the rate of neutralization by weathering in sensitive watersheds.The intensive interest in past and present global climate change has renewed efforts to understand quantitatively feedback mechanisms between climate and chemical weathering. On timescales longer than a million years, atmospheric CO2 levels have been primarily controlled by the balance between the rate of volcanic inputs from the Earth's interior and the rate of uptake through chemical weathering of silicates at the Earth's surface (Ruddiman, 1997). Weathering is proposed as the principal moderator in controlling large increases and decreases in global temperature and precipitation through the greenhouse effects of CO2 over geologic time (R. A. Berner and E. K. Berner, 1997). Weathering processes observed in paleosols, discussed elsewhere in this volume (see Chapter 5.18), have also been proposed as indicating changes in Archean atmospheric CO2 and O2 levels (Ohmoto, 1996; Rye and Holland, 1998).

USGS Field Activities 11CEV01 and 11CEV02 on the West Florida Shelf, Gulf of Mexico, in January and February 2011

USGS Publications Warehouse

Robbins, Lisa L.; Knorr, Paul O.; Daly, Kendra L.; Taylor, Carl A.

2014-01-01

During January and February 2011 the U.S. Geological Survey (USGS), in cooperation with the University of South Florida (USF), conducted geochemical surveys on the west Florida Shelf. Data collected will allow USGS and USF scientists to investigate the effects of climate change on ocean acidification within the northern Gulf of Mexico, specifically, the effect of ocean acidification on marine organisms and habitats. This work is part of a larger USGS study on Climate and Environmental Variability (CEV). The first cruise was conducted from January 3 – 7 (11CEV01) and the second from February 17 - 27 (11CEV02). To view each cruise's survey lines, please see the Trackline page. Both cruises took place aboard the R/V Weatherbird II, a ship of opportunity led by Dr. Kendra Daly (USF), which departed and returned from Saint Petersburg, Florida. Data collection included sampling of the surface and water column (referred to as station samples) with lab analysis of pH, dissolved inorganic carbon (DIC), and total alkalinity. Augmenting the lab analysis was a continuous flow-through system with a Conductivity-Temperature-Depth (CTD) sensor, which also recorded salinity, and pH. Corroborating the USGS data are the vertical CTD profiles collected by USF. The CTD casts measured continuous vertical profiles of oxygen, chlorophyll fluorescence, optical backscatter, and transmissometer. Discrete samples for nutrients, chlorophyll, and particulate organic carbon/nitrogen were also collected during the CTD casts.

Spatial characterization of acid rain stress in Canadian Shield Lakes

NASA Technical Reports Server (NTRS)

Tanis, F. J.; Marshall, E. M.

1989-01-01

The lake acidification in Northern Ontario was investigated using LANDSAT TM to sense lake volume reflectance and also to provide important vegetation and terrain characteristics. The purpose of this project was to determine the ability of LANDSAT to assess water quality characteristics associated with lake acidification. Results demonstrate that a remote sensor can discriminate lake clarity based upon reflection. The basic hypothesis is that seasonal and multi-year changes in lake optical transparency are indicative of sensitivity to acidic deposition. In many acid-sensitive lakes optical transparency is controlled by the amount of dissolved organic carbon present. Seasonal changes in the optical transparency of lakes can potentially provide an indication of the stress due to acid deposition and loading.

AFM imaging of milk casein micelles: evidence for structural rearrangement upon acidification.

PubMed

Ouanezar, Mustapha; Guyomarc'h, Fanny; Bouchoux, Antoine

2012-03-20

Milk casein micelles are natural association colloids that we all encounter in everyday life, yet we still lack an accurate description of their internal structure and the interactions that stabilize it. In this letter, we provide for the first time detailed images of intact casein micelles as obtained through atomic force microscopy under liquid conditions close to physiological. The micelles appear as heterogeneous raspberry-like particles, which is consistent with a hierarchical/spongelike structure made of connected 10-40 nm dense casein regions. Upon in situ acidification to pH 5, the micelles decrease in size and lose their surface heterogeneities, indicating that this structure is highly sensitive to variations in mineral content and caseins net charge.

Use of soil-streamwater relationships to assess regional patterns of acidic deposition effects in the northeastern USA

USGS Publications Warehouse

Siemion, Jason; Lawrence, Gregory B.; Murdoch, Peter S.

2013-01-01

Declines of acidic deposition levels by as much as 50% since 1990 have led to partial recovery of surface waters in the northeastern USA but continued depletion of soil calcium through this same period suggests a disconnection between soil and surface water chemistry. To investigate the role of soil-surface water interactions in recovery from acidification, the first regional survey to directly relate soil chemistry to stream chemistry during high flow was implemented in a 4144-km2 area of the Catskill region of New York, where acidic deposition levels are among the highest in the East.More than 40% of 95 streams sampled in the southern Catskill Mountains were determined to be acidified and had inorganic monomeric aluminum concentrations that exceeded a threshold that is toxic to aquatic biota. More than 80% likely exceeded this threshold during the highest flows, but less than 10% of more than 100 streams sampled were acidified in the northwestern portion of the region. Median Oa horizon soil base saturation ranged from 50% to 80% at 200 sites across the region, but median base saturation in the upper 10 cm of the B horizon was less than 20% across the region and was only 2% in the southern area. Aluminum is likely to be interfering with root uptake of calcium in the mineral horizon in approximately half the sampled watersheds. Stream chemistry was highly variable over the Catskill region and, therefore, did not always reflect the calcium depletion of the B horizon that our sampling suggested was nearly ubiquitous throughout the region. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Shell Condition and Survival of Puget Sound Pteropods Are Impaired by Ocean Acidification Conditions

PubMed Central

Busch, D. Shallin; Maher, Michael; Thibodeau, Patricia; McElhany, Paul

2014-01-01

We tested whether the thecosome pteropod Limacina helicina from Puget Sound, an urbanized estuary in the northwest continental US, experiences shell dissolution and altered mortality rates when exposed to the high CO2, low aragonite saturation state (Ωa) conditions that occur in Puget Sound and the northeast Pacific Ocean. Five, week-long experiments were conducted in which we incubated pteropods collected from Puget Sound in four carbon chemistry conditions: current summer surface (∼460–500 µatm CO2, Ωa≈1.59), current deep water or surface conditions during upwelling (∼760 and ∼1600–1700 µatm CO2, Ωa≈1.17 and 0.56), and future deep water or surface conditions during upwelling (∼2800–3400 µatm CO2, Ωa≈0.28). We measured shell condition using a scoring regime of five shell characteristics that capture different aspects of shell dissolution. We characterized carbon chemistry conditions in statistical analyses with Ωa, and conducted analyses considering Ωa both as a continuous dataset and as discrete treatments. Shell dissolution increased linearly as aragonite saturation state decreased. Discrete treatment comparisons indicate that shell dissolution was greater in undersaturated treatments compared to oversaturated treatments. Survival increased linearly with aragonite saturation state, though discrete treatment comparisons indicated that survival was similar in all but the lowest saturation state treatment. These results indicate that, under starvation conditions, pteropod survival may not be greatly affected by current and expected near-future aragonite saturation state in the NE Pacific, but shell dissolution may. Given that subsurface waters in Puget Sound’s main basin are undersaturated with respect to aragonite in the winter and can be undersaturated in the summer, the condition and persistence of the species in this estuary warrants further study. PMID:25162395

Shell condition and survival of Puget Sound pteropods are impaired by ocean acidification conditions.

PubMed

Busch, D Shallin; Maher, Michael; Thibodeau, Patricia; McElhany, Paul

2014-01-01

We tested whether the thecosome pteropod Limacina helicina from Puget Sound, an urbanized estuary in the northwest continental US, experiences shell dissolution and altered mortality rates when exposed to the high CO2, low aragonite saturation state (Ωa) conditions that occur in Puget Sound and the northeast Pacific Ocean. Five, week-long experiments were conducted in which we incubated pteropods collected from Puget Sound in four carbon chemistry conditions: current summer surface (∼460-500 µatm CO2, Ωa≈1.59), current deep water or surface conditions during upwelling (∼760 and ∼1600-1700 µatm CO2, Ωa≈1.17 and 0.56), and future deep water or surface conditions during upwelling (∼2800-3400 µatm CO2, Ωa≈0.28). We measured shell condition using a scoring regime of five shell characteristics that capture different aspects of shell dissolution. We characterized carbon chemistry conditions in statistical analyses with Ωa, and conducted analyses considering Ωa both as a continuous dataset and as discrete treatments. Shell dissolution increased linearly as aragonite saturation state decreased. Discrete treatment comparisons indicate that shell dissolution was greater in undersaturated treatments compared to oversaturated treatments. Survival increased linearly with aragonite saturation state, though discrete treatment comparisons indicated that survival was similar in all but the lowest saturation state treatment. These results indicate that, under starvation conditions, pteropod survival may not be greatly affected by current and expected near-future aragonite saturation state in the NE Pacific, but shell dissolution may. Given that subsurface waters in Puget Sound's main basin are undersaturated with respect to aragonite in the winter and can be undersaturated in the summer, the condition and persistence of the species in this estuary warrants further study.

Why Do Organisms in the Atlantic Ocean Produce So Much CaCO3?

NASA Astrophysics Data System (ADS)

Toggweiler, J. R.

2010-12-01

Sediments in the Atlantic are richer in CaCO3 than sediments in the other oceans. Sediment trap observations show that sinking particles in the Atlantic also tend to have more CaCO3 in relation to organic carbon than sinking particles elsewhere. The reason for the extra production of CaCO3 has never been very clear. The Atlantic is unusual because it receives much more than its share of the global input of river water. River water adds alkalinity to the surface ocean while the production of CaCO3 takes it away. In this presentation a new tracer, called Alk*, is derived from the surface alkalinity distribution to highlight the impact of river inputs and the production of CaCO3. If the production of CaCO3 were evenly distributed across the ocean one would expect the Atlantic to have a higher level of Alk* becaused of its river inputs. We find instead that Alk* is lower in the middle of the Atlantic than almost any place else. This, of course, is consistent with the fact that organisms in the Atlantic produce a lot of CaCO3. Comparison with other areas with especially low values of Alk* (Red Sea and northern Arabian Sea) shows that the production of CaCO3 is highly correlated across the ocean with the surface salinity. Hence, we argue that organisms in the Atlantic produce a lot of CaCO3 simply because the Atlantic is so salty. Salty waters, by definition, have more CO3= ions, which increase the supersaturation with respect to calcite and aragonite. This finding, while extremely simple, has major implifications for the impact of ocean acidification on calcifying organisms.

Solar Radiation Management and Olivine Dissolution Methods in Climate Engineering

NASA Astrophysics Data System (ADS)

Kone, S.

2014-12-01

An overview of solar radiation management and olivine dissolution methods allows to discuss, comparatively, the benefits and consequences of these two geoengineering techniques. The combination of those two techniques allows to concomitantly act on the two main agents intervening in global warming: solar radiation and carbon dioxide. The earth surface temperature increases due mainly to carbon dioxide (a greenhouse gas) that keeps the solar radiation and causes the global warming. Two complementary methods to mitigate climate change are overviewed: SRM method, which uses injected aerosols, aims to reduce the amount of the inbound solar radiation in atmosphere; and olivine dissolution in water, a key chemical reaction envisaged in climate engineering , aiming to reduce the amount of the carbon dioxide in extracting it from atmosphere. The SRM method works on scenarios of solar radiation decrease and the olivine dissolution method works as a carbon dioxide sequestration method. Olivine dissolution in water impacts negatively on the pH of rivers but positively in counteracting ocean acidification and in transporting the silica in ocean, which has benefits for diatom shell formation.

Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms.

PubMed

Orr, James C; Fabry, Victoria J; Aumont, Olivier; Bopp, Laurent; Doney, Scott C; Feely, Richard A; Gnanadesikan, Anand; Gruber, Nicolas; Ishida, Akio; Joos, Fortunat; Key, Robert M; Lindsay, Keith; Maier-Reimer, Ernst; Matear, Richard; Monfray, Patrick; Mouchet, Anne; Najjar, Raymond G; Plattner, Gian-Kasper; Rodgers, Keith B; Sabine, Christopher L; Sarmiento, Jorge L; Schlitzer, Reiner; Slater, Richard D; Totterdell, Ian J; Weirig, Marie-France; Yamanaka, Yasuhiro; Yool, Andrew

2005-09-29

Today's surface ocean is saturated with respect to calcium carbonate, but increasing atmospheric carbon dioxide concentrations are reducing ocean pH and carbonate ion concentrations, and thus the level of calcium carbonate saturation. Experimental evidence suggests that if these trends continue, key marine organisms--such as corals and some plankton--will have difficulty maintaining their external calcium carbonate skeletons. Here we use 13 models of the ocean-carbon cycle to assess calcium carbonate saturation under the IS92a 'business-as-usual' scenario for future emissions of anthropogenic carbon dioxide. In our projections, Southern Ocean surface waters will begin to become undersaturated with respect to aragonite, a metastable form of calcium carbonate, by the year 2050. By 2100, this undersaturation could extend throughout the entire Southern Ocean and into the subarctic Pacific Ocean. When live pteropods were exposed to our predicted level of undersaturation during a two-day shipboard experiment, their aragonite shells showed notable dissolution. Our findings indicate that conditions detrimental to high-latitude ecosystems could develop within decades, not centuries as suggested previously.

Pteropods are excellent recorders of surface temperature and carbonate ion concentration.

PubMed

Keul, N; Peijnenburg, K T C A; Andersen, N; Kitidis, V; Goetze, E; Schneider, R R

2017-10-03

Pteropods are among the first responders to ocean acidification and warming, but have not yet been widely explored as carriers of marine paleoenvironmental signals. In order to characterize the stable isotopic composition of aragonitic pteropod shells and their variation in response to climate change parameters, such as seawater temperature, pteropod shells (Heliconoides inflatus) were collected along a latitudinal transect in the Atlantic Ocean (31° N to 38° S). Comparison of shell oxygen isotopic composition to depth changes in the calculated aragonite equilibrium oxygen isotope values implies shallow calcification depths for H. inflatus (75 m). This species is therefore a good potential proxy carrier for past variations in surface ocean properties. Furthermore, we identified pteropod shells to be excellent recorders of climate change, as carbonate ion concentration and temperature in the upper water column have dominant influences on pteropod shell carbon and oxygen isotopic composition. These results, in combination with a broad distribution and high abundance, make the pteropod species studied here, H. inflatus, a promising new proxy carrier in paleoceanography.

Natural acidification changes the timing and rate of succession, alters community structure, and increases homogeneity in marine biofouling communities.

PubMed

Brown, Norah E M; Milazzo, Marco; Rastrick, Samuel P S; Hall-Spencer, Jason M; Therriault, Thomas W; Harley, Christopher D G

2018-01-01

Ocean acidification may have far-reaching consequences for marine community and ecosystem dynamics, but its full impacts remain poorly understood due to the difficulty of manipulating pCO 2 at the ecosystem level to mimic realistic fluctuations that occur on a number of different timescales. It is especially unclear how quickly communities at various stages of development respond to intermediate-scale pCO 2 change and, if high pCO 2 is relieved mid-succession, whether past acidification effects persist, are reversed by alleviation of pCO 2 stress, or are worsened by departures from prior high pCO 2 conditions to which organisms had acclimatized. Here, we used reciprocal transplant experiments along a shallow water volcanic pCO 2 gradient to assess the importance of the timing and duration of high pCO 2 exposure (i.e., discrete events at different stages of successional development vs. continuous exposure) on patterns of colonization and succession in a benthic fouling community. We show that succession at the acidified site was initially delayed (less community change by 8 weeks) but then caught up over the next 4 weeks. These changes in succession led to homogenization of communities maintained in or transplanted to acidified conditions, and altered community structure in ways that reflected both short- and longer-term acidification history. These community shifts are likely a result of interspecific variability in response to increased pCO 2 and changes in species interactions. High pCO 2 altered biofilm development, allowing serpulids to do best at the acidified site by the end of the experiment, although early (pretransplant) negative effects of pCO 2 on recruitment of these worms were still detectable. The ascidians Diplosoma sp. and Botryllus sp. settled later and were more tolerant to acidification. Overall, transient and persistent acidification-driven changes in the biofouling community, via both past and more recent exposure, could have important implications for ecosystem function and food web dynamics. © 2017 John Wiley & Sons Ltd.

Modeling the long-term deposition trends in US over 1990-2010 and impacts on the ecosystem assessment

EPA Science Inventory

Reactive nitrogen (Nr) is very important pollutant which at the same time plays a very important role on air and water quality, human health and biological diversity. The atmospheric nitrogen deposition can cause acidification and excess eutrophication, which brings damages to th...

Identifying Local Factors that May Exacerbate Coastal Acidification in Pacific Northwest Estuaries

EPA Science Inventory

US EPA initiated a study in the Tillamook estuary and watershed focused on the impact of changes in watershed land use, ocean conditions, and weather on estuarine water quality and ecosystem goods and services production within the estuary. This project is a collaboration betwee...

Climate Change, Adaptation and Security in Central America and the Caribbean (CSL Issue Paper, Volume 3-11)

DTIC Science & Technology

2011-03-01

associated disturbances, such as flooding, drought, wildfire, insects, and ocean acidification , and the global change drivers of land use change, pollution...coastlines, overfishing, water contamination due to pollution and destruction of coral reefs were also identified as concerns. A general attendee

Fate of Ammonia Emissions at the Local to Regional Scale as Simulated by the Community Multiscale Air Quality Model

EPA Science Inventory

Atmospheric deposition of nitrogen contributes to eutrophication of estuarine waters and acidification of lakes and streams. Ammonia also contributes to fine particle formation in the atmosphere and associated health effects. Model projections suggest that NH₃ depositi...

Prolonged acid rain facilitates soil organic carbon accumulation in a mature forest in Southern China.

PubMed

Wu, Jianping; Liang, Guohua; Hui, Dafeng; Deng, Qi; Xiong, Xin; Qiu, Qingyan; Liu, Juxiu; Chu, Guowei; Zhou, Guoyi; Zhang, Deqiang

2016-02-15

With the continuing increase in anthropogenic activities, acid rain remains a serious environmental threat, especially in the fast developing areas such as southern China. To detect how prolonged deposition of acid rain would influence soil organic carbon accumulation in mature subtropical forests, we conducted a field experiment with simulated acid rain (SAR) treatments in a monsoon evergreen broadleaf forest at Dinghushan National Nature Reserve in southern China. Four levels of SAR treatments were set by irrigating plants with water of different pH values: CK (the control, local lake water, pH ≈ 4.5), T1 (water pH=4.0), T2 (water pH=3.5), and T3 (water pH=3.0). Results showed reduced pH measurements in the topsoil exposed to simulated acid rains due to soil acidification. Soil respiration, soil microbial biomass and litter decomposition rates were significantly decreased by the SAR treatments. As a result, T3 treatment significantly increased the total organic carbon by 24.5% in the topsoil compared to the control. Furthermore, surface soil became more stable as more recalcitrant organic matter was generated under the SAR treatments. Our results suggest that prolonged acid rain exposure may have the potential to facilitate soil organic carbon accumulation in the subtropical forest in southern China. Copyright © 2015 Elsevier B.V. All rights reserved.

Odor tracking in sharks is reduced under future ocean acidification conditions.

PubMed

Dixson, Danielle L; Jennings, Ashley R; Atema, Jelle; Munday, Philip L

2015-04-01

Recent studies show that ocean acidification impairs sensory functions and alters the behavior of teleost fishes. If sharks and other elasmobranchs are similarly affected, this could have significant consequences for marine ecosystems globally. Here, we show that projected future CO2 levels impair odor tracking behavior of the smooth dogfish (Mustelus canis). Adult M. canis were held for 5 days in a current-day control (405 ± 26 μatm) and mid (741 ± 22 μatm) or high CO2 (1064 ± 17 μatm) treatments consistent with the projections for the year 2100 on a 'business as usual' scenario. Both control and mid CO2 -treated individuals maintained normal odor tracking behavior, whereas high CO2 -treated sharks significantly avoided the odor cues indicative of food. Control sharks spent >60% of their time in the water stream containing the food stimulus, but this value fell below 15% in high CO2 -treated sharks. In addition, sharks treated under mid and high CO2 conditions reduced attack behavior compared to the control individuals. Our findings show that shark feeding could be affected by changes in seawater chemistry projected for the end of this century. Understanding the effects of ocean acidification on critical behaviors, such as prey tracking in large predators, can help determine the potential impacts of future ocean acidification on ecosystem function. © 2014 John Wiley & Sons Ltd.

Long term soil pH change in rainfed cropping systems: is acidification systemic?

USDA-ARS?s Scientific Manuscript database

Many soils throughout the northern Great Plains developed from deep, moderately-weathered glacial and loess deposits under prairie vegetation. Soils of this type are typically neutral to slightly acidic in near-surface depths, and slightly to strongly alkaline in subsoil depths, with high buffer cap...

Novel nanodispersed coal liquefaction catalysts: Molecular design via microemulsion-based synthesis. Final technical report, October 1990--December 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Osseo-Asare, K.; Boakye, E.; Vittal, M.

1995-04-01

This report described the synthesis of Molybdenum Sulfides in microemulsions by acidification of ammonium tetrathiomolybdate. Molybdenum Sulfides have been shown to be potential coal liquefaction catalysts. The importance of particle size, temperature effects, and coal surface chemistry to impregnation are discussed.

Investigation on physicochemical properties of plasma-activated water for the application of medical device sterilization

NASA Astrophysics Data System (ADS)

Abuzairi, Tomy; Ramadhanty, Savira; Puspohadiningrum, Dini Fithriaty; Ratnasari, Anita; Poespawati, Nji Raden; Purnamaningsih, Retno Wigajatri

2018-02-01

Plasma activated water (PAW) is a new approach to bacterial inactivation while ensuring safety and maintaining the properties of the material sterilized. Reported research imply that PAW has been effective for inactivation of bacteria. In this paper, plasma treatment using atmospheric pressure plasma was demonstrated. Physicochemical properties such as pH, temperature, ORP, and nitrite concentration were assessed. The results suggest that plasma treatment causes acidification on water and generate reactive species, creating an environment suitable for killing bacteria. Therefore, plasma activated water is an assuring method for medical devices sterilization.

Mechanistic basis of adaptive maternal effects: egg jelly water balance mediates embryonic adaptation to acidity in Rana arvalis.

PubMed

Shu, Longfei; Suter, Marc J-F; Laurila, Anssi; Räsänen, Katja

2015-11-01

Environmental stress, such as acidification, can challenge persistence of natural populations and act as a powerful evolutionary force at ecological time scales. The ecological and evolutionary responses of natural populations to environmental stress at early life-stages are often mediated via maternal effects. During early life-stages, maternal effects commonly arise from egg coats (the extracellular structures surrounding the embryo), but the role of egg coats has rarely been studied in the context of adaptation to environmental stress. Previous studies on the moor frog Rana arvalis found that the egg coat mediated adaptive divergence along an acidification gradient in embryonic acid stress tolerance. However, the exact mechanisms underlying these adaptive maternal effects remain unknown. Here, we investigated the role of water balance and charge state (zeta potential) of egg jelly coats in embryonic adaptation to acid stress in three populations of R. arvalis. We found that acidic pH causes severe water loss in the egg jelly coat, but that jelly coats from an acid-adapted population retained more water than jelly coats from populations not adapted to acidity. Moreover, embryonic acid tolerance (survival at pH 4.0) correlated with both water loss and charge state of the jelly, indicating that negatively charged glycans influence jelly water balance and contribute to embryonic adaptation to acidity. These results indicate that egg coats can harbor extensive intra-specific variation, probably facilitated in part via strong selection on water balance and glycosylation status of egg jelly coats. These findings shed light on the molecular mechanisms of environmental stress tolerance and adaptive maternal effects.

From the Ground Up: Building an Earth Science Satellite (HyspIRI Hawaii, Part 5)

NASA Image and Video Library

2017-05-01

Scientists from NASA and University of Hawaii, in partnership the U.S. Naval Research Laboratory, teamed up in February 2017 to study the health of coral reefs located around the Hawaiian Islands for the Hyperspectral InfraRed Imager (HyspIRI) airborne preparatory mission. Research divers and an autonomous kayak monitored coral color signatures from the ocean floor and surface, while NASA’s high-altitude ER-2 collected images of the same areas from a height of 70,000 ft. The data from these sources are being combined to better understand how coral reef ecosystems are responding to stressful conditions like warming ocean temperatures and water acidification. Data from this mission will potentially help develop a NASA satellite to study natural hazards and ecosystems all over the world. Learn more about the HyspIRI airborne mission here: https://www.jpl.nasa.gov/news/news.php?feature=6793

Hg(2+) detection using a disposable and miniaturized screen-printed electrode modified with nanocomposite carbon black and gold nanoparticles.

PubMed

Cinti, Stefano; Santella, Francesco; Moscone, Danila; Arduini, Fabiana

2016-05-01

A miniaturized screen-printed electrode (SPE) modified with a carbon black-gold nanoparticle (CBNP-AuNP) nanocomposite has been developed as an electrochemical sensor for the detection of inorganic mercury ions (Hg(2+)). The working electrode surface has been modified with nanocomposite constituted of CBNPs and AuNPs by an easy drop casting procedure that makes this approach extendible to an automatable mass production of modified SPEs. Square wave anodic stripping voltammetry (SWASV) was adopted to perform Hg(2+) detection, revealing satisfactory sensitivity and detection limit, equal to 14 μA ppb(-1) cm(-2) and 3 ppb, respectively. The applicability of the CBNP-AuNP-SPE for the determination of inorganic mercury has been assessed in river water by a simple filtration and acidification of the sample as well as in soil by means of a facile acidic extraction procedure assisted by ultrasound.

Difference in physiological responses of growth, photosynthesis and calcification of the coccolithophore Emiliania huxleyi to acidification by acid and CO2 enrichment.

PubMed

Fukuda, Shin-Ya; Suzuki, Yurina; Shiraiwa, Yoshihiro

2014-09-01

Ocean acidification, one of the great global environmental issues at present, is expected to result in serious damage on marine calcareous organisms such as corals and calcifying algae, which potentially release huge amounts of CO2 from the ocean to the atmosphere. The coccolithophore, Emiliania huxleyi (Haptophyceae), which frequently produces blooms, has greatly contributed to the biological CO2 pump. This study was aimed at analyzing effects of how E. huxleyi responds to acidification. Acidification was performed by two methods, namely by just adding HCl under bubbling ordinary air at 8.2-8.4, 7.6-7.8 and 7.1-7.3 (acidification by HCl) and by bubbling with ordinary air or with increased CO2 concentration such as 406, 816 and 1,192 ppm that maintained pH of the medium at 8.0-8.3, 7.6-7.9 and 7.5-7.7 (acidification by CO2 enrichment). As a result, cell growth and cellular calcification of E. huxleyi were strongly damaged by acidification by HCl, but not by acidification by CO2 enrichment. The activities of photosystems such as F v/F m and ϕPSII were not affected by any acidification conditions while photosynthetic O2 evolution was slightly stimulated. A (45)Ca-radiotracer experiment revealed that Ca(2+)-uptake was strongly suppressed by acidification with HCl. This suppression recovered after increasing the dissolved inorganic carbon (DIC) concentration and further stimulated by an additional increase in DIC concentration. The production of storage and coccolith polysaccharides was increased by acidification by HCl and also highly stimulated by acidification with CO2 enrichment. The present study clearly showed that the coccolithophore, E. huxleyi, has an ability to respond positively to acidification with CO2 enrichment, but not just acidification.

Studies of acid-base homeostasis during simulated weightlessness: Application of the water immersion model to man

NASA Technical Reports Server (NTRS)

Epstein, M.

1975-01-01

The effects of water immersion on acid-base homeostasis were investigated under carefully controlled conditions. Studies of renal acidification were carried out on seven healthy male subjects, each consuming a diet containing 150 meq sodium and 100 meq potassium. Control and immersion studies were carried out on each subject on the fourth and sixth days, respectively, of dietary equilibration, by which time all subjects had achieved sodium balance. The experimental protocols on study days were similar (except for the amount of water administered).

The positive relationship between ocean acidification and pollution.

PubMed

Zeng, Xiangfeng; Chen, Xijuan; Zhuang, Jie

2015-02-15

Ocean acidification and pollution coexist to exert combined effects on the functions and services of marine ecosystems. Ocean acidification can increase the biotoxicity of heavy metals by altering their speciation and bioavailability. Marine pollutants, such as heavy metals and oils, could decrease the photosynthesis rate and increase the respiration rate of marine organisms as a result of biotoxicity and eutrophication, facilitating ocean acidification to varying degrees. Here we review the complex interactions between ocean acidification and pollution in the context of linkage of multiple stressors to marine ecosystems. The synthesized information shows that pollution-affected respiration acidifies coastal oceans more than the uptake of anthropogenic carbon dioxide. Coastal regions are more vulnerable to the negative impact of ocean acidification due to large influxes of pollutants from terrestrial ecosystems. Ocean acidification and pollution facilitate each other, and thus coastal environmental protection from pollution has a large potential for mitigating acidification risk. Copyright © 2014 Elsevier Ltd. All rights reserved.

Using Critical Loads to Look at Improvements in Acidic Surface Water Conditions since the 1990 Amendments to the Clear Air Act: Case Study Adirondack, NY

NASA Astrophysics Data System (ADS)

Lynch, J. A.; Kolian, M. J.; Haeuber, R.

2008-12-01

Acid deposition has affected hundreds of lakes and thousands of miles of headwater streams in the Adirondack region of New York State. The diversity of life in these acidic waters has been greatly reduced. The poor buffering capacity of the thin, acidic soils in the Adirondack Mountains makes the lakes and ponds particularly susceptible to acidification. Since the mid-1990's, lakes in the Adirondack region are finally showing signs of recovery. The good news is that emissions of sulfur dioxide and nitrogen oxides have been reduced and as a result acidic deposition of sulfate and nitrate has decreased in surface waters approximately 26 and 13%, respectively. This has led to improvement in the acid neutralizing capacity (ANC) of these water bodies. Although improvement in water quality is a good sign, it does not tell us if a particular lake or a group of lakes have recovered from decades of acidic deposition. However, the critical loads approach does allow for evaluation of whether a water body has reached recovery for acidic deposition. Critical loads and exceedances for lake surface water and acidity were calculated for 187 lakes in the Adirondack region. The Steady-State Water Chemistry (SSWC) model was used to calculate the critical load, relying on water chemistry data from the TIME/LTM network. An ANC threshold of 50 μeq/L was selected for this case study. Exceedances were calculated from deposition for the period before implementation of the Acid Rain program (ARP) (1989-1991) and for the period of 2004-2006 to judge improvements as a result of the ARP. On average, the critical load for lakes in the Adirondack region is 164 meq/m2/yr, while it is 48 meq/m2/yr for the most sensitive lakes (i.e. ANC less than 100 μeq/L). For the period from 2004 to 2006, 65% of the lakes within the TIME/LTM network continued to receive levels of acid deposition that exceeded the lake's critical load down from 72% of lakes before implementation of the Acid Rain Program. Despite improvement in water quality that has occurred over the past decades in the Adirondack region additional reduction in acidic deposition is needed in order for greater recovery of these sensitive aquatic systems.

Data-collection methods and quality-assurance/quality-control procedures used in the study of episodic stream acidification and its effect on fish and aquatic invertebrates in four Catskill Mountain streams, New York, 1988-90

USGS Publications Warehouse

Ranalli, Anthony J.; Baldigo, Barry P.; Horan-Ross, Debra; Allen, Ronald V.

1997-01-01

The U.S. Geological Survey, in cooperation with the U.S. Environmental Protection Agency, conducted a 20-month study during 1988-90 to evaluate the effects of episodic acidification on fish and aquatic invertebrates in pristine headwater streams in the Catskill Mountains of New York. The study was part of the Episodic Response Project, a regional survey of episodic acidification by the U.S. Environmental Protection Agency, and was carried out simultaneously with other studies in the Adirondack Mountains of New York by the Adirondack Lake Survey Corporation and in central Pennsylvania by Pennsylvania State University. This report summarizes the methods used, describes the sampling sites, and presents the data collected from October 1, 1988 through May 30, 1990 at four headwater watersheds (Biscuit Brook, East Branch Neversink River, Black Brook, and High Falls Brook). The study entailed (1) monitoring the quantity and chemical quality of atmospheric deposition and the quality of discharge of streams, and (2) experiments to determine the effect of stream-water-quality changes on fish and invertebrate populations.

Combined hydrolysis acidification and bio-contact oxidation system with air-lift tubes and activated carbon bioreactor for oilfield wastewater treatment.

PubMed

Guo, Chunmei; Chen, Yi; Chen, Jinfu; Wang, Xiaojun; Zhang, Guangqing; Wang, Jingxiu; Cui, Wenfeng; Zhang, Zhongzhi

2014-10-01

This paper investigated the enhancement of the COD reduction of an oilfield wastewater treatment process by installing air-lift tubes and adding an activated carbon bioreactor (ACB) to form a combined hydrolysis acidification and bio-contact oxidation system with air-lift tubes (HA/air-lift BCO) and an ACB. Three heat-resistant bacterial strains were cultivated and subsequently applied in above pilot plant test. Installing air-lift tubes in aerobic tanks reduced the necessary air to water ratio from 20 to 5. Continuous operation of the HA/air-lift BCO system for 2 months with a hydraulic retention time of 36 h, a volumetric load of 0.14 kg COD/(m(3)d) (hydrolysis-acidification or anaerobic tank), and 0.06 kg COD/(m(3)d) (aerobic tanks) achieved an average reduction of COD by 60%, oil and grease by 62%, total suspended solids by 75%, and sulfides by 77%. With a COD load of 0.56 kg/(m(3)d), the average COD in the ACB effluent was 58 mg/L. Copyright © 2014 Elsevier Ltd. All rights reserved.

Descriptive risk assessment of the effects of acidic deposition on Rocky Mountain amphibians

USGS Publications Warehouse

Corn, Paul Stephen; Vertucci, Frank A.

1992-01-01

We evaluated the risk of habitat acidification to the six species of amphibians that occur in the mountains of Colorado and Wyoming. Our evaluation included extrinsic environmental factors (habitat sensitivity and amount of acidic atmospheric deposition) and species-specific intrinsic factors (sensitivity to acid conditions, habitat preferences, and timing of breeding). Only one of 57 surveyed localities had both acid neutralizing capacity μeq/L and sulfate deposition >10 kg/ha/yr, extrinsic conditions with a possible risk of acidification. Amphibian breeding habitats in the Rocky Mountains do not appear to be sufficiently acidic to kill amphibian embryos. Some species breed in high-elevation vernal pools during snowmelt, and an acidic pulse during snowmelt may pose a risk to embryos of these species. However, the acidic pulse, if present, probably occurs before open water appears and before breeding begins. Although inherent variability of amphibian population size may make detection of declines from anthropogenic effects difficult, acidic deposition is unlikely to have caused the observed declines of Bufo boreas and Rana pipiens in Colorado and Wyoming. Amphibians in the Rocky Mountains are not likely to be at risk with acidification inputs at present levels.

Effect of ocean acidification on the structure and fatty acid composition of a natural plankton community in the Baltic Sea

NASA Astrophysics Data System (ADS)

Bermúdez, Rafael; Winder, Monika; Stuhr, Annegret; Almén, Anna-Karin; Engström-Öst, Jonna; Riebesell, Ulf

2016-12-01

Increasing atmospheric carbon dioxide (CO2) is changing seawater chemistry towards reduced pH, which affects various properties of marine organisms. Coastal and brackish water communities are expected to be less affected by ocean acidification (OA) as these communities are typically adapted to high fluctuations in CO2 and pH. Here we investigate the response of a coastal brackish water plankton community to increasing CO2 levels as projected for the coming decades and the end of this century in terms of community and biochemical fatty acid (FA) composition. A Baltic Sea plankton community was enclosed in a set of offshore mesocosms and subjected to a CO2 gradient ranging from natural concentrations ( ˜ 347 µatm fCO2) up to values projected for the year 2100 ( ˜ 1333 µatm fCO2). We show that the phytoplankton community composition was resilient to CO2 and did not diverge between the treatments. Seston FA composition was influenced by community composition, which in turn was driven by silicate and phosphate limitation in the mesocosms and showed no difference between the CO2 treatments. These results suggest that CO2 effects are dampened in coastal communities that already experience high natural fluctuations in pCO2. Although this coastal plankton community was tolerant of high pCO2 levels, hypoxia and CO2 uptake by the sea can aggravate acidification and may lead to pH changes outside the currently experienced range for coastal organisms.