Assessment of the theory and hypotheses of the acidification of watersheds

Energy Technology Data Exchange (ETDEWEB)

Krug, E.C.

1989-04-01

This report documents and critically assesses the evolution and status of the scientific understanding of the effects of acidic deposition on surface waters. The main conclusion is that the dominant theory of surface-water acidification fails to adequately incorporate many important factors and processes that influence surface water acidity. Some of these factors and processes are not well researched or recognized as being important by most scientists in the aquatic effects research area. 258 refs., 14 figs., 23 tabs.

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

Science.gov (United States)

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.

Food supply confers calcifiers resistance to ocean acidification

KAUST Repository

Ramajo, Laura; Pé rez-Leó n, Elia; Hendriks, Iris E.; Marbà , Nú ria; 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

KAUST Repository

Ramajo, Laura

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.

Planning of an Integrated Acidification Study and Survey on Acid Rain Impacts in China. Final Report

Energy Technology Data Exchange (ETDEWEB)

Lydersen, Espen; Angell, Valter; Eilertsen, Odd; Muniz, Ivar P. [Norsk Inst. for Naturforskning, Trondheim (Norway); Larssen, Thorbjoern; Seip, Hans Martin; Aagaard, Per; Vogt, Rolf D. [Oslo Univ. (Norway); Mulder, Jan

1997-12-31

This is the final report from the PIAC project, which was a multidisciplinary survey on acid rain in China. One goal was to document effects of airborne acidifying compounds on vegetation, soil, soil- and surface-water and aquatic biota. Other goals were to exchange knowledge between Chinese and Norwegian scientists, and to visit research sites in highly polluted areas in China and evaluate their need of support in a future collaborative monitoring and research programme. Samples have been collected from over 20 sites in three areas. Negative effects of air pollution are found on all ecosystem levels investigated. The concentration of sulfur in the air in urban and near-urban areas is very high. The concentration of volatile organic compounds is generally high, which means that increased NOx emissions in coming years may increase the ozone problems. Reduced photosynthesis activities were found in some plants and acidification observed in soil and surface water. Aquatic biota also reflect the acidification status of the surface waters investigated. However, it is difficult to assess the degree of damage in these regions because the survey includes too few sites. Surface water acidification is currently not a major environmental problem in China and is unlikely to be one during the next decades. The report includes a status report on acidification in China and a proposed framework for a monitoring programme based on Norwegian experiences. 139 refs., 16 figs., 45 tabs.

Assessing recovery from acidification of European surface waters in the year 2010: Evaluation of projections made with the MAGIC model in 1995

Czech Academy of Sciences Publication Activity Database

Helliwell, R. C.; Wright, R. F.; Jackson-Blake, L.A.; Ferrier, R. C.; Aherne, J.; Cosby, B. J.; Evans, C. D.; Forsius, M.; Hruška, J.; Jenkins, A.; Krám, P.; Kopáček, Jiří; Majer, V.; Moldan, F.; Posch, M.; Potts, J. M.; Rogora, M.; Schöpp, W.

2014-01-01

Roč. 48, č. 22 (2014), s. 13280-13288 ISSN 0013-936X Grant - others:EC(XE) RECOVER:2010 EVK1-CT-1999-00018 Institutional support: RVO:60077344 Keywords : atmospheric acidification * sulphur * nitrogen * Tatra Mountains Subject RIV: DJ - Water Pollution ; Quality Impact factor: 5.330, year : 2014

Extreme Weather Years Drive Episodic Acidification and Brownification in Lakes in the Northeast US: Implications for Long-term Shifts in Dissolved Organic Carbon, Water Clarity, and Thermal Structure

Science.gov (United States)

Strock, K.; Saros, J. E.

2017-12-01

Interannual climate variability is expected to increase over the next century, but the extent to which hydroclimatic variability influences biogeochemical processes is unclear. To determine the effects of extreme weather on surface water chemistry, a 30-year record of surface water geochemistry for 84 lakes in the northeastern U.S. was combined with landscape data and watershed-specific weather data. With these data, responses in sulfate and dissolved organic carbon (DOC) concentrations were characterized during extreme wet and extreme dry conditions. Episodic acidification during drought and episodic brownification (increased DOC) during wet years were detected broadly across the northeastern U.S. Episodic chemical response was linearly related to wetland coverage in lake watersheds only during extreme wet years. The results of a redundancy analysis suggest that topographic features also need to be considered and that the interplay between wetlands and their degree of connectivity to surface waters could be driving episodic acidification in this region. A subset of lakes located in Acadia National Park, Maine U.S.A. were studied to better understand the implications of regional increases of DOC in lakes. Water transparency declined across six study sites since 1995 as DOC increased. As clarity declined, some lakes experienced reduced epilimnion thickness. The degree to which transparency changed across the lakes was dependent on DOC concentration, with a larger decline in transparency occurring in clear water lakes than brown water lakes. The results presented here help to clarify the variability observed in long-term recovery from acidification and regional increases in DOC. Specifically, an increased frequency of extreme wet years may be contributing to a recent acceleration in the recovery of lake ecosystems from acidification; however, increased frequency of wet years may also lead to reduced water clarity and altered physical lake habitat. Clarifying the

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

Science.gov (United States)

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.

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

Science.gov (United States)

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 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.

Deterioration of atlantic soft water macrophyte communities by acidification, eutrophication and alkalinisation

NARCIS (Netherlands)

Arts, G.H.P.

2002-01-01

This review presents an overview of the most important succession patterns and underlying processes associated with the deterioration of soft water macrophyte communities in atlantic and boreo-atlantic regions. As acidification, eutrophication and alkalinisation are the dominant processes, this

Gases (CH4, CO2 and N2 and pore water chemistry in the surface sediments of Lake Orta, Italy: acidification effects on C and N gas cycling

Directory of Open Access Journals (Sweden)

Donald D. ADAMS

2001-02-01

Full Text Available Lake Orta, a subalpine, warm monomictic lake in northwestern Italy was heavily polluted from rayon factory discharges of ammonium and copper since 1926. In the 1950s accumulations of contaminants resulted in whole lake pHs of 3.8-4.0 from ammonium oxidation. Partial remediation started in the 1950s, but by 1985-89 the water remained acidified at pHs of 4.0. Artificial liming (14,500 t in 1989-90 resulted in improved water quality and substantial recovery of the biological community. Sediment gases, sampled in 1989 before liming, from the lake's four basins showed severe inhibition of methanogenesis (CH4 = 0.0-0.15 mM in the surface sediments (0.5-5 cm of the southern basin, location of the plant effluent, as compared to the deep central and northern basins (0.9-1.4 mM. Four years after liming, cores collected in 1994 near the 1989 southern basin sites showed a slight change in surface sediment methane (0.07-0.82 mM, yet suggested continual sediment toxicity, at least to carbon cycling through methanogenesis. Calculations of diffuse flux of CH4 at the sediment-water interface (SWI in 1989 were 6.6-7.4 mM m-2 day-1 for the central and northern basins and 0.13 for the southern basin. CH4 fluxes increased 16x to 2 mM m-2 day-1 in 1994 in the southern basin, possibly from remediation of near surface sediments. The impact of pollution on denitrification (formation of sediment N2 gas was not so obvious since two processes could counteract each other (high NO3 - stimulating denitrification versus possible negative effects from acidity and metals. The calculated flux of N2 from the southern basin sediments increased 5x four years after liming compared to the period of acidification, suggesting possible toxicity towards denitrifiers during the earlier period. Core overlying water (0.68 mM exhibited N2 concentrations close to saturation, while most surface sediments were twice as much (1.5 mM. Surface (0-6 cm sediment N2 was similar at most sites, with the

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

NARCIS (Netherlands)

Gazeau, F.; van Rijswijk, P.; Pozzato, L.; Middelburg, J.J.

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

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

NARCIS (Netherlands)

Gazeau, F.; van Rijswijk, P.; Pozzato, L.; Middelburg, J.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

Long-term records and modelling of acidification, recovery and liming at Lake Hovvatn, Norway

Energy Technology Data Exchange (ETDEWEB)

Hindar, A. [Norwegian Inst. for Water Research, Grimstad (Norway); Wright, R.F. [Norwegian Inst. for Water Research, Oslo (Norway)

2005-11-01

Scenarios for acidification in Europe have shown that large parts of southern Norway will be negatively impacted by sulfur (S) and nitrogen (N) emissions in the future. Long-term data of acidification and recovery as well as the effects of a liming program at Lake Store Hovvatn were presented in this paper, along with data collected from Lake Lille Hovvatn as unlimed reference. Water samples from the lakes were collected 5 times annually from varying depths. Total organic carbon was measured after wet chemical oxidation by infrared detection. Acidification hindcasts and forecasts for the period 1870-2050 were conducted with the dynamic model MAGIC, which simulated soil solution and surface water chemistry to predict average concentrations of the major ions. The model showed good agreement with major changes in water chemistry observed over the past 30 years, as well simulating pH and concentrations of inorganic aluminium (Al). The data were evaluated in terms of the prospects for the re-establishment of a self-sustaining brown trout population. All liming efforts at Lake Store Hovvatn resulted in improvements in water quality. However, the stocked fish showed excellent survival and growth rates after liming but no natural recruitment, which suggested that fish eggs at shallow depths under ice cover are a sensitive biological indicator. Continuous records of pH revealed serious difficulties in maintaining adequate water quality at shallow depths in winter. While various liming techniques were discussed, it was concluded that the problem of surface water acidification in southern Norway is not solved, and a long-term strategy is called for. 45 refs., 5 tabs., 6 figs.

Ocean acidification impacts bacteria – phytoplankton coupling at low-nutrient conditions

NARCIS (Netherlands)

Hornick, T.; Bach, L.T.; Crawfurd, K.J.; Spilling, K.; Achterberg, E.P.; Woodhouse, J.N.; Schulz, K.G.; Brussaard, C.P.D.; Riebesell, U.; Grossart, H.-P.

2017-01-01

The oceans absorb about a quarter of the annuallyproduced anthropogenic atmospheric carbon dioxide(CO2/, resulting in a decrease in surface water pH, aprocess termed ocean acidification (OA). Surprisingly littleis known about how OA affects the physiology of heterotrophicbacteria or the coupling of

Impacts of Ocean Acidification

Energy Technology Data Exchange (ETDEWEB)

Bijma, Jelle (Alfred Wegener Inst., D-27570 Bremerhaven (Germany)) (and others)

2009-08-15

There is growing scientific evidence that, as a result of increasing anthropogenic carbon dioxide (CO{sub 2}) emissions, absorption of CO{sub 2} by the oceans has already noticeably increased the average oceanic acidity from pre-industrial levels. This global threat requires a global response. According to the Intergovernmental Panel on Climate Change (IPCC), continuing CO{sub 2} emissions in line with current trends could make the oceans up to 150% more acidic by 2100 than they were at the beginning of the Anthropocene. Acidification decreases the ability of the ocean to absorb additional atmospheric CO{sub 2}, which implies that future CO{sub 2} emissions are likely to lead to more rapid global warming. Ocean acidification is also problematic because of its negative effects on marine ecosystems, especially marine calcifying organisms, and marine resources and services upon which human societies largely depend such as energy, water, and fisheries. For example, it is predicted that by 2100 around 70% of all cold-water corals, especially those in the higher latitudes, will live in waters undersaturated in carbonate due to ocean acidification. Recent research indicates that ocean acidification might also result in increasing levels of jellyfish in some marine ecosystems. Aside from direct effects, ocean acidification together with other global change-induced impacts such as marine and coastal pollution and the introduction of invasive alien species are likely to result in more fragile marine ecosystems, making them more vulnerable to other environmental impacts resulting from, for example, coastal deforestation and widescale fisheries. The Marine Board-ESF Position Paper on the Impacts of Climate Change on the European Marine and Coastal Environment - Ecosystems indicated that presenting ocean acidification issues to policy makers is a key issue and challenge. Indeed, as the consequences of ocean acidification are expected to emerge rapidly and drastically, but are

Predicting watershed acidification under alternate rainfall conditions

International Nuclear Information System (INIS)

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, USA 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 soilwater 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 distributions of rainfall, or evapotranspiration will change net soil water flux and, consequently, will affect the dynamics of the acidification response to continued sulfate loading. 29 refs., 7 figs., 4 tabs

Coastal Acidification as Nutrients Over Enrichment Impact: A Case Study in Ambon Bay, Indonesia

Directory of Open Access Journals (Sweden)

Idha Yulia Ikhsani

2017-05-01

Full Text Available Ambon Bay is a silled bay on Ambon Island consisting of two regions, Inner Ambon Bay (IAB and Outer Ambon Bay (OAB that are separated by shallow sill. Ambon bay and its surrounding have economically important ecosystem since the utilization for many activities. The bay is affected by anthropogenic impacts associated with urbanization, climate change, and nutrients over enrichment. The “deep water-rich nutrients” from Banda Sea that enter the bay during Southeast monsoon also contribute to this enrichment as well as the nutrients transport from the land. The high concentration of nutrients increases carbon dioxide level and promotes acidifications. There are literatures about nutrients over enrichment in Ambon Bay, however, little is known about coastal acidification as nutrients over enrichment impact. In order to study the effect of nutrients distribution on the acidity of Ambon Bay, the researchers measured pH and concentrations of nutrients {nitrate + nitrite (N+N and Soluble Reactive Phosphate (SRP} from water samples collected in 7 stations on both IAB and OAB during Southeast monsoon. The results showed that in surface water, nutrients concentrations is increased from May to June due to the “deep water flushing” occurrence on May and increased precipitations from May to June. From July to August, the nutrients concentrations on surface layer decreased, due to the decreased precipitations. In column and bottom water, the nutrients concentrations were increased from May to August. While the acidity have reverse pattern from the nutrients, when nutrient concentrations increased the acidity was decreased. From correlation test, pH was not significantly correlated with the concentrations of nutrients on surface water, but showed significantly correlated on column and bottom water. The results indicated that the distribution of nutrients on column and bottom water might be an important environmental factor affecting the acidification of

Decreased abundance of crustose coralline algae due to ocean acidification

Science.gov (United States)

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.

Summertime calcium carbonate undersaturation in shelf waters of the western Arctic Ocean – how biological processes exacerbate the impact of ocean acidification

Directory of Open Access Journals (Sweden)

N. R. Bates

2013-08-01

Full Text Available The Arctic Ocean accounts for only 4% of the global ocean area, but it contributes significantly to the global carbon cycle. Recent observations of seawater CO2-carbonate chemistry in shelf waters of the western Arctic Ocean, primarily in the Chukchi Sea, from 2009 to 2011 indicate that bottom waters are seasonally undersaturated with respect to calcium carbonate (CaCO3 minerals, particularly aragonite. Nearly 40% of sampled bottom waters on the shelf have saturation states less than one for aragonite (i.e., Ωaragonite 3-secreting organisms, while 80% of bottom waters present had Ωaragonite values less than 1.5. Our observations indicate seasonal reduction of saturation states (Ω for calcite (Ωcalcite and aragonite (Ωaragonite in the subsurface in the western Arctic by as much as 0.8 and 0.5, respectively. Such data indicate that bottom waters of the western Arctic shelves were already potentially corrosive for biogenic and sedimentary CaCO3 for several months each year. Seasonal changes in Ω are imparted by a variety of factors such as phytoplankton photosynthesis, respiration/remineralization of organic matter and air–sea gas exchange of CO2. Combined, these processes either increase or enhance in surface and subsurface waters, respectively. These seasonal physical and biological processes also act to mitigate or enhance the impact of Anthropocene ocean acidification (OA on Ω in surface and subsurface waters, respectively. Future monitoring of the western Arctic shelves is warranted to assess the present and future impact of ocean acidification and seasonal physico-biogeochemical processes on Ω values and Arctic marine ecosystems.

Forest blowdown and lake acidification

International Nuclear Information System (INIS)

Dobson, J.E.; Rush, R.M.; Peplies, R.W.

1990-01-01

The authors examine the role of forest blowdown in lake acidification. The approach combines geographic information systems (GIS) and digital remote sensing with traditional field methods. The methods of analysis consist of direct observation, interpretation of satellite imagery and aerial photographs, and statistical comparison of two geographical distributions-one representing forest blow-down and another representing lake chemistry. Spatial and temporal associations between surface water pH and landscape disturbance are strong and consistent in the Adirondack Mountains of New York. In 43 Adirondack Mountain watersheds, lake pH is associated with the percentage of the watershed area blown down and with hydrogen ion deposition (Spearman rank correlation coefficients of -0.67 and -0.73, respectively). Evidence of a temporal association is found at Big Moose Lake and Jerseyfield Lake in New York and the Lygners Vider Plateau of Sweden. They conclude that forest blowdown facilities the acidification of some lakes by altering hydrologic pathways so that waters (previously acidified by acid deposition and/or other sources) do not experience the neutralization normally available through contact with subsurface soils and bedrock. Increased pipeflow is suggested as a mechanism that may link the biogeochemical impacts of forest blowdown to lake chemistry

Long-Term Patterns in C-Q Relations in an Adirondack Stream Reveal Decreasing Severity of Episodic Acidification

Science.gov (United States)

Burns, D. A.; Lawrence, G. B.; Driscoll, C. T.; Sullivan, T. J.; Shao, S.; McDonnell, T. C.

2017-12-01

Episodic acidification occurs when surface water pH and ANC decrease temporarily during rain events and snowmelt. The principal drivers of episodic acidification are increases in sulfuric acid, nitric acid, organic acids, and dilution of base cations. In regions where surface waters are sensitive to acid deposition, ANC values may approach or decline below 0 µeq/L during high flows, which may result in deleterious effects to sensitive aquatic biota. The Adirondack Mountains of New York have abundant streams and lakes, many of which are highly sensitive to the effects of acid deposition. Long-term monitoring data indicate that pH and ANC in regional surface waters are increasing in response to decreases in the acidity of atmospheric deposition that result from decreasing SO2 and NOx emissions as the Clean Air Act and its ancillary rules and amendments have been implemented. Most surface-water monitoring focuses on low-flow and broad seasonal patterns, and less is known about how episodic acidification has responded to emissions decreases. Here, we report on spatial and temporal patterns in episodic acidification through analysis of C-Q relations from surveys that target varying flow conditions as well as data from a few long-term intensively sampled stream monitoring sites. Each stream sample was assigned a Q percentile value based on a resident or nearby gage, and a statistical relation between ANC values and Q percentile was developed. The magnitude of episodic decreases in ANC increases as low-flow ANC increases, a pattern that likely results from an increasing influence of dilution, especially evident when low-flow ANC values exceed 100 µeq/L. Chronically acidic streams with low-flow ANC near 0 µeq/L show little episodic acidification, whereas streams with low-flow ANC values of about 50 µeq/L generally show ANC decreases to less than 0 µeq/L at high flow. Preliminary analysis of a 24-yr data set (1991-2014) at Buck Creek indicates that increases in high

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

Science.gov (United States)

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.

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

Science.gov (United States)

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

Influence of Acidification on the Partitioning of Steroid Hormones among Filtrate, Filter Media, and Retained Particulate Matter.

Science.gov (United States)

Havens, Sonya M; Hedman, Curtis J; Hemming, Jocelyn D C; Mieritz, Mark G; Shafer, Martin M; Schauer, James J

2016-09-01

Hormone contamination of aquatic systems has been shown to have deleterious effects on aquatic biota. However, the assessment of hormone contamination of aquatic environments requires a quantitative evaluation of the potential effects of sample preservation on hormone concentrations. This study investigated the influence of acidification (pH 2) of surface water samples on the partitioning of hormones among filtrate, filter media, and filter-retained particulate matter. Hormones were spiked into unpreserved and sulfuric acid-preserved ultrapure water and surface water runoff samples. The samples were filtered, and hormones were extracted from the filter and filtrate and analyzed by high-performance liquid chromatography. Acidification did not influence the partitioning of hormones onto the filter media. For the majority of the hormones investigated in this study, the partitioning of hormones to the filter-retained particulate matter was not influenced by acidification. Acidification increased the partitioning of progesterone and melengestrol acetate onto the retained particulate matter (about 25% for both analytes). Incorporation of an isotopically labeled internal standard (ISTD) for progesterone accounted for the loss of progesterone to the filter-retained particulates and resulted in accurate concentrations of progesterone in the filtrate. The incorporation of an ISTD for melengestrol acetate, however, was unable to account for the loss of melengestrol acetate to the retained particulates and resulted in underestimations of melengestrol acetate in the filtrate. Our results indicate that the analysis of melengestrol acetate in acid preserved surface runoff samples should be conducted on the filter-retained particulates as well as the filtrate. Copyright © by the American Society of Agronomy, Crop Science Society of America, and Soil Science Society of America, Inc.

Biological responses to acidification reversal in Cumbrian streamwaters - stream water chemistry

Energy Technology Data Exchange (ETDEWEB)

Tipping, E.; Hardie, D.J.; Lawlor, A.J.; Lofts, S.; Simon, B.M.; Vincent, C.D. [Institute of Freshwater Ecology, Ambleside (United Kingdom)

1999-07-01

This reports summarises the findings of a study sampling the streams for invertebrates and comparing the results with those made in the 1960s and 1970s, The distribution of the bacterium Cytophaga was examined, and the results of the chemical analysis of the stream waters were compared with the results from previous years. The background to the study is traced, and details of the sampling and chemical analysis are given. Evidence of the reversal of acidification in the streams is considered.

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

Science.gov (United States)

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 (...

Land use influences on acidification and recovery of freshwaters in Galloway, south-west Scotland

Directory of Open Access Journals (Sweden)

R. C. Helliwell

2001-01-01

Full Text Available The long term response of surface waters to changes in sulphur deposition and afforestation is investigated for three upland river systems in the Galloway region of south-west Scotland. From 1984-1999, these rivers exhibited a statistically significant decline in non-marine sulphate concentrations in response to reduced acid deposition. This reduction in non-marine sulphate was, however, insufficient to induce a pH recovery over the period. A statistically significant increase in river pH was observed between 1956-1970 (0.05 yr-1 when subsidised agricultural lime payments were at a maximum. In 1976, this subsidy ceased and surface waters have progressively acidified. In addition, climatic change is found to influence long-term trends in pH. Mean annual pH was greatest during a dry period between 1969-1973 when total annual discharge was low. Thereafter, pH declined gradually in response to higher rainfall and increased total annual discharge. Overall, surface waters draining the afforested catchments of the Rivers Cree and Bladnoch are more acid than those draining the moorland catchment of the Luce. These results indicate that in afforested catchments, current reductions in sulphur emissions have not led to an observed improvement in the acid status of surface waters. Forestry, therefore, represents a confounding factor with regard to chemical recovery from acidification in this region. Keywords: acidification, afforestation, deposition, rivers, lochs, non-marine sulphate, pH

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

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Lisa L Robbins

Full Text Available 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.

The subtle effects of sea water acidification on the amphipod Gammarus locusta

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J. Williams

2009-08-01

Full Text Available We report an investigation of the effects of increases in pCO2 on the survival, growth and molecular physiology of the neritic amphipod Gammarus locusta which has a cosmopolitan distribution in estuaries. Amphipods were reared from juvenile to mature adult in laboratory microcosms at three different levels of pH in nominal range 8.1–7.6. Growth rate was estimated from weekly measures of body length. At sexual maturity the amphipods were sacrificed and assayed for changes in the expression of genes coding for a heat shock protein (hsp70 gene and the metabolic enzyme glyceraldehyde-3-phosphate dehydrogenase (gapdh gene. The data show that the growth and survival of this species is not significantly impacted by a decrease in sea water pH of up to 0.5 units. Quantitative real-time PCR analysis indicated that there was no significant effect of growth in acidified sea water on the sustained expression of the hsp70 gene. There was a consistent and significant increase in the expression of the gapdh gene at a pH of ~7.5 which, when combined with observations from other workers, suggests that metabolic changes may occur in response to acidification. It is concluded that sensitive assays of tissue physiology and molecular biology should be routinely employed in future studies of the impacts of sea water acidification as subtle effects on the physiology and metabolism of coastal marine species may be overlooked in conventional gross "end-point" studies of organism growth or mortality.

Ocean acidification and calcium carbonate saturation states in the coastal zone of the West Antarctic Peninsula

NARCIS (Netherlands)

Jones, Elizabeth M.; Fenton, Mairi; Meredith, Michael P.; Clargo, Nicola M.; Ossebaar, Sharyn; Ducklow, Hugh W.; Venables, Hugh J.; de Baar, Henricus

The polar oceans are particularly vulnerable to ocean acidification; the lowering of seawater pH and carbonate mineral saturation states due to uptake of atmospheric carbon dioxide (CO2). High spatial variability in surface water pH and saturation states (Omega) for two biologically-important

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

Science.gov (United States)

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.

Ocean acidification and calcium carbonate saturation states in the coastal zone of the West Antarctic Peninsula

NARCIS (Netherlands)

Jones, E.M.; Fenton, M.; Meredith, M.P.; Clargo, N.M.; Ossebaar, S.; Ducklow, H.W.; Venables, H.J.; De Baar, H.J.W.

2017-01-01

The polar oceans are particularly vulnerable to ocean acidification; the lowering of seawater pH and carbonate mineral saturation states due to uptake of atmospheric carbon dioxide (CO2). High spatial variability in surface water pH and saturation states (Ω) for two biologically-important calcium

Building a new regulatory paradigm for coastal and estuarine acidification

Science.gov (United States)

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.

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

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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 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.

Long-term response in episodic acidification to declining SO42– deposition in two streams in Nova Scotia

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H. Laudon

2002-01-01

Full Text Available Trends in anthropogenically driven episodic acidification associated with extended winter snow melt/rain episodes between 1983 and 1998 were investigated for two streams in Nova Scotia, Canada. The anthropogenic contribution to Acid Neutralization Capacity (ANC was analysed using the Boreal Dilution Model (Bishop et al., 2000 modified by applying a sea-salt correction to all input hydrochemistry. The anthropogenic contribution to episodic ANC decline was statistically significant and strongly correlated with the decline in acid deposition, which decreased by approximately 50% during the period of record. Sensitivity analysis demonstrated that the BDM can be applied to surface waters with sea-salt contributions although the correction increases model uncertainty. Results of this study demonstrate the effectiveness of reduced emissions in North America in the last decades in decreasing the severity of episodic acidification in the Atlantic region of Canada. Keywords: episodic acidification, acidification recovery, Nova Scotia, snowmelt, winter

Ocean Acidification Refugia of the Florida Reef Tract

Science.gov (United States)

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.

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Derek P Manzello

Full Text Available 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.

Sampling depth confounds soil acidification outcomes

Science.gov (United States)

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...

Ocean acidification alters temperature and salinity preferences in larval fish.

Science.gov (United States)

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.

Atmospheric acidification of mineral aerosols: a source of bioavailable phosphorus for the oceans

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A. Nenes

2011-07-01

Full Text Available Primary productivity of continental and marine ecosystems is often limited or co-limited by phosphorus. Deposition of atmospheric aerosols provides the major external source of phosphorus to marine surface waters. However, only a fraction of deposited aerosol phosphorus is water soluble and available for uptake by phytoplankton. We propose that atmospheric acidification of aerosols is a prime mechanism producing soluble phosphorus from soil-derived minerals. Acid mobilization is expected to be pronounced where polluted and dust-laden air masses mix. Our hypothesis is supported by the soluble compositions and reconstructed pH values for atmospheric particulate matter samples collected over a 5-yr period at Finokalia, Crete. In addition, at least tenfold increase in soluble phosphorus was observed when Saharan soil and dust were acidified in laboratory experiments which simulate atmospheric conditions. Aerosol acidification links bioavailable phosphorus supply to anthropogenic and natural acidic gas emissions, and may be a key regulator of ocean biogeochemistry.

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Biogeochemical processes and buffering capacity concurrently affect acidification in a seasonally hypoxic coastal marine basin

Science.gov (United States)

Hagens, M.; Slomp, C. P.; Meysman, F. J. R.; Seitaj, D.; Harlay, J.; Borges, A. V.; Middelburg, J. J.

2015-03-01

Coastal areas are impacted by multiple natural and anthropogenic processes and experience stronger pH fluctuations than the open ocean. These variations can weaken or intensify the ocean acidification signal induced by increasing atmospheric pCO2. The development of eutrophication-induced hypoxia intensifies coastal acidification, since the CO2 produced during respiration decreases the buffering capacity in any hypoxic bottom water. To assess the combined ecosystem impacts of acidification and hypoxia, we quantified the seasonal variation in pH and oxygen dynamics in the water column of a seasonally stratified coastal basin (Lake Grevelingen, the Netherlands). Monthly water-column chemistry measurements were complemented with estimates of primary production and respiration using O2 light-dark incubations, in addition to sediment-water fluxes of dissolved inorganic carbon (DIC) and total alkalinity (TA). The resulting data set was used to set up a proton budget on a seasonal scale. Temperature-induced seasonal stratification combined with a high community respiration was responsible for the depletion of oxygen in the bottom water in summer. The surface water showed strong seasonal variation in process rates (primary production, CO2 air-sea exchange), but relatively small seasonal pH fluctuations (0.46 units on the total hydrogen ion scale). In contrast, the bottom water showed less seasonality in biogeochemical rates (respiration, sediment-water exchange), but stronger pH fluctuations (0.60 units). This marked difference in pH dynamics could be attributed to a substantial reduction in the acid-base buffering capacity of the hypoxic bottom water in the summer period. Our results highlight the importance of acid-base buffering in the pH dynamics of coastal systems and illustrate the increasing vulnerability of hypoxic, CO2-rich waters to any acidifying process.

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

Science.gov (United States)

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.

Ocean acidification postcards

Science.gov (United States)

Schreppel, Heather A.; Cimitile, Matthew J.

2011-01-01

The U.S. Geological Survey (USGS) is conducting research on ocean acidification in polar, temperate, subtropical, and tropical regions including the Arctic, West Florida Shelf, and the Caribbean. Project activities include field assessment, experimental laboratory studies, and evaluation of existing data. The USGS is participating in international and interagency working groups to develop research strategies to increase understanding of the global implications of ocean acidification. Research strategies include new approaches for seawater chemistry observation and modeling, assessment of physiological effects on organisms, changes in marine ecosystem structure, new technologies, and information resources. These postcards highlight ongoing USGS research efforts in ocean acidification and carbon cycling in marine and coastal ecosystems in three different regions: polar, temperate, and tropical. To learn more about ocean acidification visit: http://coastal.er.usgs.gov/ocean-acidification/.

Sea Water Acidification Affects Osmotic Swelling, Regulatory Volume Decrease and Discharge in Nematocytes of the Jellyfish Pelagia noctiluca

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Rossana Morabito

2013-12-01

Full Text Available Background: 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. Methods: 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. Results: 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. Conclusion: 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.

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

Science.gov (United States)

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.

Coral and mollusc resistance to ocean acidification adversely affected by warming

Science.gov (United States)

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.

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

NARCIS (Netherlands)

Webb, A.L.; Leedham-Elvidge, E.; Hughes, C.; Hopkins, F.E.; Malin, G.; Bach, L.T.; Schulz, K.; Crawfurd, K.; Brussaard, C.P.D.; Stuhr, A.; Riebesell, U.; Liss, P.S.

2016-01-01

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

Differential response of two Mediterranean cold-water coral species to ocean acidification

Science.gov (United States)

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.

Time of Emergence of Ocean Interior Acidification and De-oxygenation in a Water Mass Framework

Science.gov (United States)

Coronado, M.; Frenger, I.; Froelicher, T. L.; Rodgers, K. B.; Schlunegger, S.; Sasano, D.; Ishii, M.

2016-02-01

Potential marine ecosystem stressors, such as acidification and de-oxygenation, are expected to impact biology over the course of the 21st century. Detection of these changes in ocean biogeochemistry is made complicated by the background natural variability of the climate system (Frölicher et al., 2007 and Rodgers et al., 2015). Here we present a novel method for the interpretation of ocean interior measurement for environmental change. We use a water mass framework to compare a high-frequency repeat hydrographic section at 165E in the Pacific (Sasano et al., 2015) with initial condition ensemble experiments ran with GFDL's Earth System Model (ESM2M). In this study, "emergence" for a trend occurs when an anthropogenic signal (either modeled or observed) exceeds the noise (envelope of spread amongst ensemble members, generated by internal variability). By using a water mass as opposed to the standard depth framework, we remove the effects of anthropogenic trends and internal variability of deepening isopycnals, allowing for greater emergence of bio-geochemical signals. We find that emergence of anthropogenic trends in acidification and omega aragonite emerge sooner and with greater confidence than do trends in ocean interior oxygen concentrations. More broadly, this study demonstrates the utility of applying initial condition ensembles to interpret ocean interior variability and trends, rather than the traditional practice of using observations to validate models.

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

Science.gov (United States)

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.

Pilot scale anaerobic acidification of waste water containing sucrose and lactate

Energy Technology Data Exchange (ETDEWEB)

Zoetemeyer, R J; Borgerding, P H; Van den Heuvel, J C; Cohen, A; Boelhouwer, C

1982-07-01

The waste water from a sugar refinery, containing principally sucrose, lactate and ethanol as organic impurities, was anaerobically acidified at a pH of approximately 5.8 and an average temperature of 29 degrees C in a 1 meter cubed upflow reactor. The residence time was decreased, in steps, from 7.2 to 1.7 h. Sucrose was effectively metabolized in all cases, whereas lactate was only decomposed at longer residence times. Ethanol was not converted. The volume activity, and the sludge activity, could be increased to 250 kg/ cubic meters/d, and 14 kg/kg/d, respectively. Results indicated that in order to operate an acidification reactor at its maximum efficiency attention should be paid to the mixing system and to maintaining a constant pH. (Refs. 18).

Ocean acidification causes structural deformities in juvenile coral skeletons.

Science.gov (United States)

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.

Effect of soil acidification on root growth, nutrient and water uptake

International Nuclear Information System (INIS)

Marschner, H.

1989-01-01

Soil acidification poses various types of stress to plants, especially Al and H + toxicity in roots and Mg and Ca deficiency in roots and shoots. The importance of the various types of stress varies with plant species, location and time. Average data of the chemical composition of the bulk soil or of the molar Ca/Al or Mg/Al ratios in the soil solution without consideration of the Al species are of limited value for precise conclusions of the actual, or for predictions of the potential risk of soil-acidity-induced inhibition of root growth and of nutritional imbalances. The root-induced changes in the rhizosphere and the consequences for Al toxicity and nutrient acquisition by plants deserve more attention. Further it should be considered that roots are not only required for anchoring higher plants in the soil and for nutrient and water uptake. Roots are also important sites for synthesis of phytohormones, cytokinins and abscisic acid in particular, which are transported into the shoots and act either as signals for the water status at the soil-root interface (ABA) or as compounds required for growth and development. Inhibition in root growth may therefore affect shoot growth by means other than water and nutrient supply. (orig./vhe)

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

Science.gov (United States)

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.

Ocean and Coastal Acidification off New England and Nova Scotia

Science.gov (United States)

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...

Base cation depletion and potential long-term acidification of Norwegian catchments

International Nuclear Information System (INIS)

Kirchner, J.W.; Lydersen, E.

1995-01-01

Long-term monitoring data from Norwegian catchments show that since the late 1970s, sulfate deposition and runoff sulfate concentrations have declined significantly. However, water quality has not significantly improved, because reductions in runoff sulfate have been matched by equal declines in calcium and magnesium concentrations. Long-term declines in runoff Ca and Mg are most pronounced at catchments subject to highly acidic deposition; the observed rates of decline are quantitatively consistent with depletion of exchangeable bases by accelerated leaching under high acid loading. Even though water quality has not recovered, reductions in acid deposition have been valuable because they have prevented significant acidification that would otherwise have occurred under constant acid deposition. Ongoing depletion of exchangeable bases from these catchments implies that continued deposition reductions will be needed to avoid further acidification and that recovery from acidification will be slow. 31 refs., 2 figs., 4 tabs

Acidification in fog and cloud water. Die Saeurebildung in Nebel- und Wolkenwasser

Energy Technology Data Exchange (ETDEWEB)

Lammel, G.; Metzig, G. (Kernforschungszentrum Karlsruhe GmbH (Germany, F.R.))

1989-01-01

The understanding of processes leading to acidification of cloud and fogwater is reviewed. The acid content is the result of homogeneous and heterogeneous reactions in the multiphase system as well as of the chemical composition of the aerosol particles. The relevant chemical reactions are evaluated in terms of their acidification potential. Aerosol particles may be incorporated into droplets through acting as condensation nucleus or through scavenging. Methods and results are presented of on-going experimental acivities with the objective of an almost complete characterization of certain fog events. (orig.).

Limacina retroversa's response to combined effects of ocean acidification and sea water freshening

Science.gov (United States)

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

Separating natural acidity from anthropogenic acidification in the spring flood of northern Sweden

International Nuclear Information System (INIS)

Laudon, Hjalmar

2000-01-01

Spring flood is an occasion for transient hydrochemical changes that profoundly effect the biodiversity of the aquatic ecosystem. Spring flood is also very susceptible to anthropogenic acidification. Belief that acid deposition is primarily responsible for pH decline during spring flood has been an important factor in the decision to spend close to one billion Swedish crowns to lime surface waters in northern Sweden during the last decade. The objective of this work is to present an operational tool, the Boreal Dilution Model (BDM), for separating and quantifying the anthropogenic and natural contributions to episodic acidification during spring flood episodes in northern Sweden. The limited data requirements of 10-15 stream water samples before and during spring flood make the BDM suitable for widespread use in environmental monitoring programs. This creates a possibility for distinguishing trends and spatial patterns in the human impact as well as natural pH decline. The results from applying the BDM, and a one point 'pBDM' version of the model, in northern Sweden demonstrate that the anthropogenic component associated with spring flood episodes is now generally limited. Instead it is the combination of natural organic acidity and dilution of the buffering capacity that is the major driving mechanism of episodic acidity during spring flood events in the region. While the anthropogenic component of episodic acidification generally contributes 0.1 to 0.3 pH units to the natural pH decline of up to 2.5 pH units, the current regional extent of areas that are severely affected by anthropogenically driven episodes is approximately 6%. Prior to the initiation of the Swedish Environmental Protection Agency's 'Episode Project' the limited spring flood data together with lack of a systematic methodology for determining liming candidates forced the liming authorities to base the remediation strategy in northern Sweden on biological indications. But, since there are more

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

Science.gov (United States)

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.

Soil Acidification due to Acid Deposition in Southern China

Energy Technology Data Exchange (ETDEWEB)

Liao, Bohan

1999-12-31

Anthropogenic emission of SO{sub 2} and NO{sub x} to the atmosphere has made acid deposition one of the most serious environmental problems. In China, acid deposition research started in the late 1970s. The present thesis is part of a joint Chinese-Norwegian research project. The main goal of the thesis was to investigate the mechanism of soil acidification, to estimate soil responses to acid deposition, and to compare relative soil sensitivity to acidification in southern China. Laboratory experiments and modelling simulations were included. Specifically, the thesis (1) studies the characteristics of anion adsorption and cation release of the soils from southern China, (2) examines the effects of increased ionic strength in the precipitation and the effects of anion adsorption on cation release from the soils, (3) compares the relative sensitivity of these soils to acidification and the potentially harmful effects of acid deposition, (4) estimates likely soil responses to different deposition scenarios, including changes in soil waters and soil properties, and (5) investigates long-term changes in soils and soil waters in the Guiyang catchment due to acid deposition. 218 refs., 31 figs., 23 tabs.

Soil Acidification due to Acid Deposition in Southern China

Energy Technology Data Exchange (ETDEWEB)

Liao, Bohan

1998-12-31

Anthropogenic emission of SO{sub 2} and NO{sub x} to the atmosphere has made acid deposition one of the most serious environmental problems. In China, acid deposition research started in the late 1970s. The present thesis is part of a joint Chinese-Norwegian research project. The main goal of the thesis was to investigate the mechanism of soil acidification, to estimate soil responses to acid deposition, and to compare relative soil sensitivity to acidification in southern China. Laboratory experiments and modelling simulations were included. Specifically, the thesis (1) studies the characteristics of anion adsorption and cation release of the soils from southern China, (2) examines the effects of increased ionic strength in the precipitation and the effects of anion adsorption on cation release from the soils, (3) compares the relative sensitivity of these soils to acidification and the potentially harmful effects of acid deposition, (4) estimates likely soil responses to different deposition scenarios, including changes in soil waters and soil properties, and (5) investigates long-term changes in soils and soil waters in the Guiyang catchment due to acid deposition. 218 refs., 31 figs., 23 tabs.

Recovery of soil water, groundwater, and streamwater from acidification at the Swedish integrated monitoring catchments.

Science.gov (United States)

Löfgren, Stefan; Aastrup, Mats; Bringmark, Lage; Hultberg, Hans; Lewin-Pihlblad, Lotta; Lundin, Lars; Karlsson, Gunilla Pihl; Thunholm, Bo

2011-12-01

Recovery from anthropogenic acidification in streams and lakes is well documented across the northern hemisphere. In this study, we use 1996-2009 data from the four Swedish Integrated Monitoring catchments to evaluate how the declining sulfur deposition has affected sulfate, pH, acid neutralizing capacity, ionic strength, aluminum, and dissolved organic carbon in soil water, groundwater and runoff. Differences in recovery rates between catchments, between recharge and discharge areas and between soil water and groundwater are assessed. At the IM sites, atmospheric deposition is the main human impact. The chemical trends were weakly correlated to the sulfur deposition decline. Other factors, such as marine influence and catchment features, seem to be as important. Except for pH and DOC, soil water and groundwater showed similar trends. Discharge areas acted as buffers, dampening the trends in streamwater. Further monitoring and modeling of these hydraulically active sites should be encouraged.

Coral and mollusc resistance to ocean acidification adversely affected by warming

OpenAIRE

Rodolfo-Metalpa, R; Houlbrèque, F; Tambutté, E; Boisson, F; Baggini, C; Patti, FP; Jeffree, R; Fine, M; Foggo, A; Gattuso, JP; Hall-Spencer, JM

2011-01-01

Increasing atmospheric carbon dioxide (CO 2) 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 CO 2 levels has already been shown for corals, molluscs and many other marine organisms. The impact of acidification on the ability of individual species to cal...

Ocean Acidification and the End-Permian Mass Extinction: To What Extent does Evidence Support Hypothesis?

Directory of Open Access Journals (Sweden)

Marie-Béatrice Forel

2012-09-01

Full Text Available Ocean acidification in modern oceans is linked to rapid increase in atmospheric CO2, raising concern about marine diversity, food security and ecosystem services. Proxy evidence for acidification during past crises may help predict future change, but three issues limit confidence of comparisons between modern and ancient ocean acidification, illustrated from the end-Permian extinction, 252 million years ago: (1 problems with evidence for ocean acidification preserved in sedimentary rocks, where proposed marine dissolution surfaces may be subaerial. Sedimentary evidence that the extinction was partly due to ocean acidification is therefore inconclusive; (2 Fossils of marine animals potentially affected by ocean acidification are imperfect records of past conditions; selective extinction of hypercalcifying organisms is uncertain evidence for acidification; (3 The current high rates of acidification may not reflect past rates, which cannot be measured directly, and whose temporal resolution decreases in older rocks. Thus large increases in CO2 in the past may have occurred over a long enough time to have allowed assimilation into the oceans, and acidification may not have stressed ocean biota to the present extent. Although we acknowledge the very likely occurrence of past ocean acidification, obtaining support presents a continuing challenge for the Earth science community.

Short-term metabolic and growth responses of the cold-water coral Lophelia pertusa to ocean acidification

Science.gov (United States)

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.

The potential of 230Th for detection of ocean acidification impacts on pelagic carbonate production

Directory of Open Access Journals (Sweden)

C. Heinze

2018-06-01

Full Text Available Concentrations of dissolved 230Th in the ocean water column increase with depth due to scavenging and downward particle flux. Due to the 230Th scavenging process, any change in the calcium carbonate (CaCO3 fraction of the marine particle flux due to changes in biological CaCO3 hard-shell production as a consequence of progressing ocean acidification would be reflected in the dissolved 230Th activity. Our prognostic simulations with a biogeochemical ocean general circulation model using different scenarios for the reduction of CaCO3 production under ocean acidification and different greenhouse gas emission scenarios – the Representative Concentration Pathways (RCPs 8.5 to 2.6 – reveal the potential for deep 230Th measurements to detect reduced CaCO3 production at the sea surface. The time of emergence of an acidification-induced signal on dissolved 230Th is of the same order of magnitude as for alkalinity measurements. Interannual and decadal variability in factors other than a reduction in CaCO3 hard-shell production may mask the ocean-acidification-induced signal in dissolved 230Th and make detection of the pure CaCO3-induced signal more difficult so that only really strong changes in marine CaCO3 export would be unambiguously identifiable soon. Nevertheless, the impacts of changes in CaCO3 export production on marine 230Th are stronger than those for changes in POC (particulate organic carbon or clay fluxes.

Effects of seawater acidification on a coral reef meiofauna community

Science.gov (United States)

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.

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

Science.gov (United States)

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 (CaTOC>2 mg/l); very calcium-poor, clear rivers (CaTOC4 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.

Impact of acidification and eutrophication on macrophyte communities in soft waters in The Netherlands

Energy Technology Data Exchange (ETDEWEB)

Roelofs, J G.M.

1983-01-01

During the last decades a strong decline has been noticed in the number of waters dominated by Littorellion species, mostly isoetids such as Lobelia dortmanna L., Isoetes lacustris L. and Littorella uniflora (L.) Aschers. Sixty-eight waters, which were known to be dominated by L. uniflora after 1950 were investigated. In 1980, L. uniflora appeared to be absent or to have strongly decreased in 53 (78%) of the waters. In 41 of them, Littorella had been replaced by submerged Juncus bulbosus L. and/or Sphagnum spp. These changes seem to have been caused by changed inorganic carbon budgets as a consequence of acidification. In the remaining 12 waters, eutrophication of the water and/or sediment seems to be responsible for the changes in the plant communities. Enrichment with phosphate of the mineral sediment alone, leads to luxurious growth of submerged, rooted macrophyte species such as Myriophyllum alterniflorum DC and Ranunculus peltatus Schrank, whereas phosphate-enrichment of both sediment and water leads to luxurious growth of pleustophytes such as Riccia fluitans L. and Lemna minor L. in small, shallow waters, and to plankton bloom and luxurious growth of epiphytes in larger, deeper waters. In these cases light limitation seems to be responsible for the disappearance or decline of the Littorellion species. 41 references, 1 figure, 4 tables.

Ocean Acidification from space: recent advances

Science.gov (United States)

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

Acidification of Earth: An assessment across mechanisms and scales

Science.gov (United States)

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.

Climate change feedbacks on future oceanic acidification

International Nuclear Information System (INIS)

McNeil, Ben I.; Matear, Richard J.

2007-01-01

Oceanic anthropogenic CO 2 uptake will decrease both the pH and the aragonite saturation state (Oarag) of seawater leading to an oceanic acidification. However, the factors controlling future changes in pH and Oarag are independent and will respond differently to oceanic climate change feedbacks such as ocean warming, circulation and biological changes. We examine the sensitivity of these two CO 2 -related parameters to climate change feedbacks within a coupled atmosphere-ocean model. The ocean warming feedback was found to dominate the climate change responses in the surface ocean. Although surface pH is projected to decrease relatively uniformly by about 0.3 by the year 2100, we find pH to be insensitive to climate change feedbacks, whereas Oarag is buffered by ∼15%. Ocean carbonate chemistry creates a situation whereby the direct pH changes due to ocean warming are almost cancelled by the pH changes associated with dissolved inorganic carbon concentrations changes via a reduction in CO 2 solubility from ocean warming. We show that the small climate change feedback on future surface ocean pH is independent to the amount of ocean warming. Our analysis therefore implies that future projections of surface ocean acidification only need to consider future atmospheric CO 2 levels, not climate change induced modifications in the ocean

Ocean acidification impairs crab foraging behaviour.

Science.gov (United States)

Dodd, Luke F; Grabowski, Jonathan H; Piehler, Michael F; Westfield, Isaac; Ries, Justin B

2015-07-07

Anthropogenic elevation of atmospheric CO2 is driving global-scale ocean acidification, which consequently influences calcification rates of many marine invertebrates and potentially alters their susceptibility to predation. Ocean acidification may also impair an organism's ability to process environmental and biological cues. These counteracting impacts make it challenging to predict how acidification will alter species interactions and community structure. To examine effects of acidification on consumptive and behavioural interactions between mud crabs (Panopeus herbstii) and oysters (Crassostrea virginica), oysters were reared with and without caged crabs for 71 days at three pCO2 levels. During subsequent predation trials, acidification reduced prey consumption, handling time and duration of unsuccessful predation attempt. These negative effects of ocean acidification on crab foraging behaviour more than offset any benefit to crabs resulting from a reduction in the net rate of oyster calcification. These findings reveal that efforts to evaluate how acidification will alter marine food webs should include quantifying impacts on both calcification rates and animal behaviour. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

The geochemistry during management of lake acidification caused by the rewetting of sulfuric (pH < 4) acid sulfate soils

International Nuclear Information System (INIS)

Mosley, Luke M.; Shand, Paul; Self, Peter; Fitzpatrick, Rob

2014-01-01

Highlights: • The dynamic geochemistry of a lake acidification event and its management was assessed. • Sulfate complexes dominated the aqueous metal speciation at low pH. • Iron oxydroxysulfate minerals (schwertmannite, jarosite) were identified. • Aerial additions of limestone to the acidic water slowly returned the pH to near neutral. • Coating of the limestone with gypsum and metal precipitates limited its neutralisation efficiency. - Abstract: Understanding the geochemistry and kinetics of acidification events arising from acid sulfate soils is important to enable effective management and risk assessment. Large-scale exposure and oxidation of acid sulfate soils occurred during a drought in the Lower Lakes (Murray–Darling Basin) of South Australia. We examined the geochemical changes that occurred in one region (Boggy Lake) that experienced surface water acidification and was subsequently neutralised via aerial limestone (CaCO 3 ) dosing and dilution via natural lake refill. Very low pH (< 3) and high concentrations (≈10–1000 mg/L Fe, Al, Mn) of dissolved metals were initially found in surface water. The water chemistry exhibited pH-dependent enhancement of constituents typically associated with acid sulfate soils (SO 4 , Al and Fe). Geochemical speciation calculations indicated that most (60–80%) of the acidity was present as dissolved metal-sulfate complexes at low pH. X-ray diffraction (XRD) analyses showed that the orange-brown precipitates present after an initial limestone dosing were secondary oxyhydroxysulfate minerals (schwertmannite, jarosite). Further limestone dosing resulted in neutralisation of the pH, reduction in dissolved metal concentrations, dissolution of jarosite and schwertmannite precipitates, and formation of other metal oxyhydroxide phases. The results were consistent with a pE-pH diagram constructed for metal-sulfur geochemistry. Assessment of the measured and simulated (using PHREEQC) pH and Ca/Cl ratio during

Ocean Acidification and Coral Reefs: An Emerging Big Picture

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John E. N. Veron

2011-05-01

Full Text Available This article summarises the sometimes controversial contributions made by the different sciences to predict the path of ocean acidification impacts on the diversity of coral reefs during the present century. Although the seawater carbonate system has been known for a long time, the understanding of acidification impacts on marine biota is in its infancy. Most publications about ocean acidification are less than a decade old and over half are about coral reefs. Contributions from physiological studies, particularly of coral calcification, have covered such a wide spectrum of variables that no cohesive picture of the mechanisms involved has yet emerged. To date, these studies show that coral calcification varies with carbonate ion availability which, in turn controls aragonite saturation. They also reveal synergies between acidification and the better understood role of elevated temperature. Ecological studies are unlikely to reveal much detail except for the observations of the effects of carbon dioxide springs in reefs. Although ocean acidification events are not well constrained in the geological record, recent studies show that they are clearly linked to extinction events including four of the five greatest crises in the history of coral reefs. However, as ocean acidification is now occurring faster than at any know time in the past, future predictions based on past events are in unchartered waters. Pooled evidence to date indicates that ocean acidification will be severely affecting reefs by mid century and will have reduced them to ecologically collapsed carbonate platforms by the century’s end. This review concludes that most impacts will be synergistic and that the primary outcome will be a progressive reduction of species diversity correlated with habitat loss and widespread extinctions in most metazoan phyla.

Effect of ocean acidification on the benthic foraminifera

NARCIS (Netherlands)

Keul, N.; Langer, G.; de Nooijer, L.J.; Bijma, J.

2013-01-01

About 30% of the anthropogenically released CO2 is taken up by the oceans; such uptake causes surface ocean pH to decrease and is commonly referred to as ocean acidification (OA). Foraminifera are one of the most abundant groups of marine calcifiers, estimated to precipitate ca. 50 % of biogenic

Intra-Specific Variation Reveals Potential for Adaptation to Ocean Acidification in a Cold-Water Coral from the Gulf of Mexico

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Melissa D. Kurman

2017-05-01

Full Text Available Ocean acidification, the decrease in seawater pH due to the absorption of atmospheric CO2, profoundly threatens the survival of a large number of marine species. Cold-water corals are considered to be among the most vulnerable organisms to ocean acidification because they are already exposed to relatively low pH and corresponding low calcium carbonate saturation states (Ω. Lophelia pertusa is a globally distributed cold-water scleractinian coral that provides critical three-dimensional habitat for many ecologically and economically significant species. In this study, four different genotypes of L. pertusa were exposed to three pH treatments (pH = 7.60, 7.75, and 7.90 over a short (2-week experimental period, and six genotypes were exposed to two pH treatments (pH = 7.60 and 7.90 over a long (6-month experimental period. Their physiological response was measured as net calcification rate and the activity of carbonic anhydrase, a key enzyme in the calcification pathway. In the short-term experiment, net calcification rates did not significantly change with pH, although they were highly variable in the low pH treatment, including some genotypes that maintained positive net calcification in undersaturated conditions. In the 6-month experiment, average net calcification was significantly reduced at low pH, with corals exhibiting net dissolution of skeleton. However, one of the same genotypes that maintained positive net calcification (+0.04% day−1 under the low pH treatment in the short-term experiment also maintained positive net calcification longer than the other genotypes in the long-term experiment, although none of the corals maintained positive calcification for the entire 6 months. Average carbonic anhydrase activity was not affected by pH, although some genotypes exhibited small, insignificant, increases in activity after the sixth month. Our results suggest that while net calcification in L. pertusa is adversely affected by ocean

Recovery from acidification of lochs in Galloway, south-west Scotland, UK: 1979-1998

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R. C. Ferrier

2001-01-01

Full Text Available The Galloway region of south-west Scotland has historically been subject to long-term deposition of acidic precipitation which has resulted in acidification of soils and surface waters and subsequent damage to aquatic ecology. Since the end of the 1970s, however, acidic deposition has decreased substantially. The general pattern is for a rapid decline in non-marine sulphate in rainwater over the period 1978-1988 followed by stable concentrations to the mid-1990s. Concentrations of nitrate and ammonium in deposition have remained constant between 1980 and 1998. Seven water quality surveys of 48 lochs in the Galloway region have been conducted between 1979 and 1998. During the first 10 years, from 1979, there was a major decline in regional sulphate concentrations in the lochs, which was expected to have produced a decline in base cations and an increase in the acid neutralising capacity. But sea-salt levels (as indicated by chloride concentrations were approximately 25% higher in 1988 than in 1979 and thus short-term acidification due to sea-salts offset much of the long-term recovery trend expected in the lochs. During the next 10 years, however, the chloride concentrations returned to 1979 levels and the lochs showed large increases in acid neutralising capacity despite little change in sulphate concentrations. From the observed decline in sulphate deposition and concentrations of sulphate in the lochs, it appears that approximately 75% of the possible improvement in acid neutralising capacity has already occurred over the 20-year period (1979-1998. The role of acid deposition as a driving factor for change in water chemistry in the Galloway lochs is confounded by concurrent changes in other driving variables, most notably, factors related to episodic and year-to-year variations in climate. In addition to inputs of sea-salts, climate probably also influences other chemical signals such as peaks in regional nitrate concentrations and the sharp

Revisiting four scientific debates in ocean acidification research

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A. J. Andersson

2012-03-01

Full Text Available In recent years, ocean acidification has gained continuously increasing attention from scientists and a number of stakeholders and has raised serious concerns about its effects on marine organisms and ecosystems. With the increase in interest, funding resources, and the number of scientific investigations focusing on this environmental problem, increasing amounts of data and results have been produced, and a progressively growing and more rigorous understanding of this problem has begun to develop. Nevertheless, there are still a number of scientific debates, and in some cases misconceptions, that keep reoccurring at a number of forums in various contexts. In this article, we revisit four of these topics that we think require further thoughtful consideration including: (1 surface seawater CO₂ chemistry in shallow water coastal areas, (2 experimental manipulation of marine systems using CO₂ gas or by acid addition, (3 net versus gross calcification and dissolution, and (4 CaCO₃ mineral dissolution and seawater buffering. As a summation of these topics, we emphasize that: (1 many coastal environments experience seawater pCO₂ that is significantly higher than expected from equilibrium with the atmosphere and is strongly linked to biological processes; (2 addition of acid, base or CO₂ gas to seawater can all be useful techniques to manipulate seawater chemistry in ocean acidification experiments; (3 estimates of calcification or CaCO₃ dissolution based on present techniques are measuring the net of gross calcification and dissolution; and (4 dissolution of metastable carbonate mineral phases will not produce sufficient alkalinity to buffer the pH and carbonate saturation state of shallow water environments on timescales of decades to hundreds of years to the extent that any potential negative effects on marine calcifiers will be avoided.

Marine oxygen holes as a consequence of oceanic acidification

Science.gov (United States)

Hofmann, M.; Schellnhuber, H.-J.

2009-04-01

An increase of atmospheric CO2 levels will not only drive future global mean temperatures towards values unprecedented during the whole Quaternary, but will also lead to an acidification of sea water which could harm the marine biota. Here we assess possible impacts of elevated atmospheric CO2 concentrations on the marine biological carbon pump by utilizing a business-as-usual emission scenario of anthropogenic CO2. A corresponding release of 4075 Petagrams of Carbon in total has been applied to simulate the current millennium by employing an Earth System Model of Intermediate Complexity (EMIC). This work is focused on studying the implications of reduced biogenic calcification caused by an increasing degree of oceanic acidification on the marine biological carbon pump. The attenuation of biogenic calcification imposes a small negative feedback on rising atmospheric pCO2 levels, tending to stabilize the Earth's climate. Since mineral ballast, notably particulate CaCO3, plays 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 dramatic effect discovered in our model world with severe consequences: since organic matter is oxidized in shallow waters when mineral-ballast fluxes weaken, oxygen holes (hypoxic zones) start to expand considerably in the oceans with potentially harmful impacts on a variety of marine ecosystems. Our study indicates that unbridled ocean acidification would exacerbate the observed hypoxia trends due to various environmental factors as reported in recent empirical studies.

Reversal of ocean acidification enhances net coral reef calcification.

Science.gov (United States)

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.

Is acidification still a major air pollution concern? The analysis from the French Agriculture and Fishing Department; Le probleme de l`acidification d`origine atmospherique est-il toujours d`actualite? l`analyse du Ministere de l`agriculture et de la peche

Energy Technology Data Exchange (ETDEWEB)

Landmann, G. [Ministere de l`Agriculture et de la Peche, 75 - Paris (France). Direction de l`espace rural et de la foret

1997-12-31

The acidification issues related to agriculture and their effects on ecosystems are analyzed: through ammonium emissions, agriculture is largely contributing to acidification and eutrophication of ecosystems; enhancements of cultivation and fertilization techniques have been achieved in order to decrease these emissions; natural soils and waters, and more especially forests, are still affected by acid and nitrogenous pollution, leading to modifications with soil degradation and eutrophication of forest soils and waters

Uranium and coexisting element behaviour in surface waters and associated sediments with varied sampling techniques used for uranium exploration

International Nuclear Information System (INIS)

Wenrich-Verbeek, K.J.

1977-01-01

Optimum sampling methods in surface water and associated sediments for use in uranium exploration are being studied at thirty sites in Colorado, New Mexico, Arizona and Utah. For water samples, filtering is recommended to increase sample homogeneity and reproducibility because for most elements studied water samples which were allowed to remain unfiltered until time of analysis contained higher concentrations than field-filtered samples of the same waters. Acidification of unfiltered samples resulted in still higher concentrations. This is predominantly because of leaching of the elements from the suspended fraction. U in water correslates directly with Ca, Mg, Na, K, Ba, B, Li and As. In stream sediments, U and other trace elements are concentrated in the finer size fractions. Accordingly, in prospecting, grain size fractions less than 90 μm (170 mesh) should be analyzed for U. A greater number of elements (21) show a significant positive correlation with U in stream sediments than in water. Results have revealed that anomalous concentrations of U found in water may not be detected in associated sediments and vice versa. Hence, sampling of both surface water and coexisting sediment is strongly recommended

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

Science.gov (United States)

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.

Estimating total alkalinity for coastal ocean acidification monitoring at regional to continental scales in Australian coastal waters

KAUST Repository

Baldry, Kimberlee; Hardman-Mountford, Nick; Greenwood, Jim

2017-01-01

Owing to a lack of resources, tools, and knowledge, the natural variability and distribution of Total Alkalinity (TA) has been poorly characterised in coastal waters globally, yet variability is known to be high in coastal regions due to the complex interactions of oceanographic, biotic, and terrestrially-influenced processes. This is a particularly challenging task for the vast Australian coastline, however, it is also this vastness that demands attention in the face of ocean acidification (OA). Australian coastal waters have high biodiversity and endemism, and are home to large areas of coral reef, including the Great Barrier Reef, the largest coral reef system in the world. Ocean acidification threatens calcifying marine organisms by hindering calcification rates, threatening the structural integrity of coral reefs and other ecosystems. Tracking the progression of OA in different coastal regions requires accurate knowledge of the variability in TA. Thus, estimation methods that can capture this variability at synoptic scales are needed. Multiple linear regression is a promising approach in this regard. Here, we compare a range of both simple and multiple linear regression models to the estimation of coastal TA from a range of variables, including salinity, temperature, chlorophyll-a concentration and nitrate concentration. We find that regionally parameterised models capture local variability better than more general coastal or open ocean parameterised models. The strongest contribution to model improvement came through incorporating temperature as an input variable as well as salinity. Further improvements were achieved through the incorporation of either nitrate or chlorophyll-a, with the combination of temperature, salinity, and nitrate constituting the minimum model in most cases. These results provide an approach that can be applied to satellite Earth observation and autonomous in situ platforms to improve synoptic scale estimation of TA in coastal waters.

Estimating total alkalinity for coastal ocean acidification monitoring at regional to continental scales in Australian coastal waters

KAUST Repository

Baldry, Kimberlee

2017-06-01

Owing to a lack of resources, tools, and knowledge, the natural variability and distribution of Total Alkalinity (TA) has been poorly characterised in coastal waters globally, yet variability is known to be high in coastal regions due to the complex interactions of oceanographic, biotic, and terrestrially-influenced processes. This is a particularly challenging task for the vast Australian coastline, however, it is also this vastness that demands attention in the face of ocean acidification (OA). Australian coastal waters have high biodiversity and endemism, and are home to large areas of coral reef, including the Great Barrier Reef, the largest coral reef system in the world. Ocean acidification threatens calcifying marine organisms by hindering calcification rates, threatening the structural integrity of coral reefs and other ecosystems. Tracking the progression of OA in different coastal regions requires accurate knowledge of the variability in TA. Thus, estimation methods that can capture this variability at synoptic scales are needed. Multiple linear regression is a promising approach in this regard. Here, we compare a range of both simple and multiple linear regression models to the estimation of coastal TA from a range of variables, including salinity, temperature, chlorophyll-a concentration and nitrate concentration. We find that regionally parameterised models capture local variability better than more general coastal or open ocean parameterised models. The strongest contribution to model improvement came through incorporating temperature as an input variable as well as salinity. Further improvements were achieved through the incorporation of either nitrate or chlorophyll-a, with the combination of temperature, salinity, and nitrate constituting the minimum model in most cases. These results provide an approach that can be applied to satellite Earth observation and autonomous in situ platforms to improve synoptic scale estimation of TA in coastal waters.

The Impact of Ocean Acidification on the Functional Morphology of Foraminifera

Science.gov (United States)

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

Influence of ocean acidification on the complexation of iron and copper by organic ligands in estuarine waters

NARCIS (Netherlands)

Gledhill, M.; Achterberg, E.P.; Li, K.; Mohamed, K.N.; Rijkenberg, M.J.

2015-01-01

The uptake of anthropogenic atmospheric CO2 by the oceans causes a shift in the carbonate chemistry system which includes a lowering of pH; this process has been termed ocean acidification. Our understanding of the specific effects of ocean acidification on chemical speciation of trace metals, in

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

Science.gov (United States)

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

New perspectives in ocean acidification research: editor's introduction to the special feature on ocean acidification.

Science.gov (United States)

Munday, Philip L

2017-09-01

Ocean acidification, caused by the uptake of additional carbon dioxide (CO 2 ) from the atmosphere, will have far-reaching impacts on marine ecosystems (Gattuso & Hansson 2011 Ocean acidification Oxford University Press). The predicted changes in ocean chemistry will affect whole biological communities and will occur within the context of global warming and other anthropogenic stressors; yet much of the biological research conducted to date has tested the short-term responses of single species to ocean acidification conditions alone. While an important starting point, these studies may have limited predictive power because they do not account for possible interactive effects of multiple climate change drivers or for ecological interactions with other species. Furthermore, few studies have considered variation in responses among populations or the evolutionary potential within populations. Therefore, our knowledge about the potential for marine organisms to adapt to ocean acidification is extremely limited. In 2015, two of the pioneers in the field, Ulf Riebesell and Jean-Pierre Gattuso, noted that to move forward as a field of study, future research needed to address critical knowledge gaps in three major areas: (i) multiple environmental drivers, (ii) ecological interactions and (iii) acclimation and adaptation (Riebesell and Gattuso 2015 Nat. Clim. Change 5 , 12-14 (doi:10.1038/nclimate2456)). In May 2016, more than 350 researchers, students and stakeholders met at the 4th International Symposium on the Ocean in a High-CO 2 World in Hobart, Tasmania, to discuss the latest advances in understanding ocean acidification and its biological consequences. Many of the papers presented at the symposium reflected this shift in focus from short-term, single species and single stressor experiments towards multi-stressor and multispecies experiments that address knowledge gaps about the ecological impacts of ocean acidification on marine communities. The nine papers in this

The Phenomenom of Ocean Acidification

Science.gov (United States)

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.

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

Science.gov (United States)

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...

Thermodynamic Forecasts of the Mediterranean Sea Acidification

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C. GOYET

2016-07-01

Full Text Available Anthropogenic CO2 is a major driver of the present ocean acidification. This latter is threatening the marine ecosystems and has been identified as a major environmental and economic menace. This study aims to forecast from the thermodynamic equations, the acidification variation (ΔpH of the Mediterranean waters over the next few decades and beyond this century. In order to do so, we calculated and fitted the theoretical values based upon the initial conditions from data of the 2013 MedSeA cruise. These estimates have been performed both for the Western and for the Eastern basins based upon their respective physical (temperature and salinity and chemical (total alkalinity and total inorganic carbon properties. The results allow us to point out four tipping points, including one when the Mediterranean Sea waters would become acid (pH<7. In order to provide an associated time scale to the theoretical results, we used two of the IPCC (2007 atmospheric CO2 scenarios. Under the most optimistic scenario of the “Special Report: Emissions Scenarios” (SRES of the IPCC (2007, the results indicate that in 2100, pH may decrease down to 0.245 in the Western basin and down to 0.242 in the Eastern basin (compared to the pre-industrial pH. Whereas for the most pessimistic SRES scenario of the IPCC (2007, the results for the year 2100, forecast a pH decrease down to 0.462 and 0.457, for the Western and for the Eastern basins, respectively. Acidification, which increased unprecedentedly in recent years, will rise almost similarly in both Mediterranean basins only well after the end of this century. These results further confirm that both basins may become undersaturated (< 1 with respect to calcite and aragonite (at the base of the mixed layer depth, only in the far future (in a few centuries.

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

KAUST Repository

Klein, Shannon G.

2017-04-08

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.

The positive relationship between ocean acidification and pollution.

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Ocean acidification

International Nuclear Information System (INIS)

Soubelet, Helene; Veyre, Philippe; Monnoyer-Smith, Laurence

2017-09-01

This brief publication first recalls and outlines that ocean acidification is expected to increase, and will result in severe ecological impacts (more fragile coral reefs, migration of species, and so on), and therefore social and economic impacts. This issue is particularly important for France who possesses the second exclusive maritime area in the world. The various impacts of ocean acidification on living species is described, notably for phytoplankton, coral reefs, algae, molluscs, and fishes. Social and economic impacts are also briefly presented: tourism, protection against risks (notably by coral reefs), shellfish aquaculture and fishing. Issues to be addressed by scientific research are evoked: interaction between elements of an ecosystem and between different ecosystems, multi-stress effects all along organism lifetime, vulnerability and adaptability of human societies

Ocean acidification challenges copepod phenotypic plasticity

Science.gov (United States)

Vehmaa, Anu; Almén, Anna-Karin; Brutemark, Andreas; Paul, Allanah; Riebesell, Ulf; Furuhagen, Sara; Engström-Öst, Jonna

2016-11-01

Ocean acidification is challenging phenotypic plasticity of individuals and populations. Calanoid copepods (zooplankton) are shown to be fairly plastic against altered pH conditions, and laboratory studies indicate that transgenerational effects are one mechanism behind this plasticity. We studied phenotypic plasticity of the copepod Acartia sp. in the course of a pelagic, large-volume mesocosm study that was conducted to investigate ecosystem and biogeochemical responses to ocean acidification. We measured copepod egg production rate, egg-hatching success, adult female size and adult female antioxidant capacity (ORAC) as a function of acidification (fCO2 ˜ 365-1231 µatm) and as a function of quantity and quality of their diet. We used an egg transplant experiment to reveal whether transgenerational effects can alleviate the possible negative effects of ocean acidification on offspring development. We found significant negative effects of ocean acidification on adult female size. In addition, we found signs of a possible threshold at high fCO2, above which adaptive maternal effects cannot alleviate the negative effects of acidification on egg-hatching and nauplii development. We did not find support for the hypothesis that insufficient food quantity (total particulate carbon < 55 µm) or quality (C : N) weakens the transgenerational effects. However, females with high-ORAC-produced eggs with high hatching success. Overall, these results indicate that Acartia sp. could be affected by projected near-future CO2 levels.

Different ecophysiological responses of freshwater fish to warming and acidification.

Science.gov (United States)

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.

Simulating the long-term chemistry of an upland UK catchment: Major solutes and acidification

Energy Technology Data Exchange (ETDEWEB)

Tipping, E. [Centre for Ecology and Hydrology (Lancaster), Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom)]. E-mail: et@ceh.ac.uk; Lawlor, A.J. [Centre for Ecology and Hydrology (Lancaster), Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom); Lofts, S. [Centre for Ecology and Hydrology (Lancaster), Library Avenue, Bailrigg, Lancaster LA1 4AP (United Kingdom)

2006-05-15

CHUM-AM was used to investigate changes in soil and water chemical variables in four moorland sub-catchments in Cumbria UK, to which non-marine S deposition has declined by 65% since the 1970s. The principal processes represented in the model comprise N and S uptake and release, water movements, the binding of cations by soil organic matter, chemical interactions in solution, and chemical weathering. CHUM-AM reproduced reasonably well the current soil pH and pools of N and S, and changes in streamwater chemistry over the period 1970-2000, notably decreases in the concentrations of alkaline earth cations and sulphate, and increases in pH. The model also predicts streamwater pH-Al relationships in agreement with observations. Predictive calculations suggest that constant atmospheric deposition of N at present rates will lead to N saturation and re-acidification, whereas a 50% reduction in N would stabilise soil and streamwater pH at about the present levels. - CHUM-AM accounts for recovery from acidification due to sulphur deposition, but predicts re-acidification if nitrogen deposition is not reduced.

Ocean acidification buffering effects of seagrass in Tampa Bay

Science.gov (United States)

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 (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.

Investigation of landscape and lake acidification relationships

Energy Technology Data Exchange (ETDEWEB)

Rush, R.M.; Honea, R.B.; Krug, E.C.; Peplies, R.W.; Dobson, J.E.; Baxter, F.P.

1985-10-01

This interim report presents the rationale and initial results for a program designed to gather and analyze information essential to a better understanding of lake acidification in the northeastern United States. The literature pertinent to a study of landscape and lake acidification relationships is reviewed and presented as the rationale for a landscape/lake acidification study. The results of a study of Emmons Pond in northwestern Connecticut are described and lead to the conclusion that a landscape change was a contributor to the acidification of this pond. A regional study of sixteen lakes in southern New England using Landsat imagery is described, and preliminary observations from a similar study in the Adirondack Mountains are given. These results indicate that satellite imagery can be useful in identifying types of ground cover important to landscape/lake acidification relationships.

Nitrate leaching as a confounding factor in chemical recovery from acidification in UK upland waters

International Nuclear Information System (INIS)

Curtis, C.J.; Evans, C.D.; Helliwell, R.C.; Monteith, D.T.

2005-01-01

Over the period 1988-2002, data from 18 of the 22 lakes and streams in the UK Acid Waters Monitoring Network (AWMN) show clear trends of declining excess sulphate concentrations in response to reductions in sulphur deposition, but fewer trends in increasing pH or alkalinity. There has been no significant decline in the deposition of total nitrogen over the same period, and no sites show a trend in nitrate concentration. Peak nitrate concentrations have already surpassed excess sulphate on occasion in half of the AWMN sites. Furthermore, current understanding of terrestrial N saturation processes suggests that nitrate leaching from soils may increase, even under a constant N deposition load. Best-case projections indicate that nitrate will overtake sulphate as the major excess acid anion in many sites within 10 years, while worst-case predictions with steady-state models suggest that in the longer-term, nitrate could become the dominant excess acid anion in most of the UK. - With declining excess sulphate, nitrate will become the dominant agent of continued anthropogenic acidification in many UK upland waters within a decade

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

Science.gov (United States)

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.

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.

Science.gov (United States)

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.

Ocean acidification challenges copepod phenotypic plasticity

Directory of Open Access Journals (Sweden)

A. Vehmaa

2016-11-01

Full Text Available Ocean acidification is challenging phenotypic plasticity of individuals and populations. Calanoid copepods (zooplankton are shown to be fairly plastic against altered pH conditions, and laboratory studies indicate that transgenerational effects are one mechanism behind this plasticity. We studied phenotypic plasticity of the copepod Acartia sp. in the course of a pelagic, large-volume mesocosm study that was conducted to investigate ecosystem and biogeochemical responses to ocean acidification. We measured copepod egg production rate, egg-hatching success, adult female size and adult female antioxidant capacity (ORAC as a function of acidification (fCO2  ∼  365–1231 µatm and as a function of quantity and quality of their diet. We used an egg transplant experiment to reveal whether transgenerational effects can alleviate the possible negative effects of ocean acidification on offspring development. We found significant negative effects of ocean acidification on adult female size. In addition, we found signs of a possible threshold at high fCO2, above which adaptive maternal effects cannot alleviate the negative effects of acidification on egg-hatching and nauplii development. We did not find support for the hypothesis that insufficient food quantity (total particulate carbon < 55 µm or quality (C : N weakens the transgenerational effects. However, females with high-ORAC-produced eggs with high hatching success. Overall, these results indicate that Acartia sp. could be affected by projected near-future CO2 levels.

Ocean acidification challenges copepod reproductive plasticity

Science.gov (United States)

Vehmaa, A.; Almén, A.-K.; Brutemark, A.; Paul, A.; Riebesell, U.; Furuhagen, S.; Engström-Öst, J.

2015-11-01

Ocean acidification is challenging phenotypic plasticity of individuals and populations. Calanoid copepods (zooplankton) are shown to be fairly plastic against altered pH conditions, and laboratory studies indicate that transgenerational effects are one mechanism behind this plasticity. We studied phenotypic plasticity of the copepod Acartia bifilosa in the course of a pelagic, large-volume mesocosm study that was conducted to investigate ecosystem and biogeochemical responses to ocean acidification. We measured copepod egg production rate, egg hatching success, adult female size and adult female antioxidant capacity (ORAC) as a function of acidification (fCO2 ~ 365-1231 μatm), and as a function of quantity and quality of their diet. We used an egg transplant experiment to reveal if transgenerational effects can alleviate the possible negative effects of ocean acidification on offspring development. We found significant negative effects of ocean acidification on adult female copepod size and egg hatching success. In addition, we found a threshold of fCO2 concentration (~ 1000 μatm), above which adaptive maternal effects cannot alleviate the negative effects of acidification on egg hatching and nauplii development. We did not find support for the hypothesis that insufficient food quantity (total particulate carbon ~ 55 μm) or quality (C : N) weakens the transgenerational effects. However, females with high ORAC produced eggs with high hatching success. Overall, these results indicate that A. bifilosa could be affected by projected near future CO2 levels.

Zooplankton community response to experimental acidification in boreal shield lakes with different ecological histories

Energy Technology Data Exchange (ETDEWEB)

Derry, A.M.; Arnott, S.E. [Queen' s Univ., Kingston, ON (Canada). Dept. of Biology

2007-06-15

This study investigated the adaptive response of crustacean zooplankton to widespread regional acidification at the Killarney Provincial Park in Ontario. Mesocosm experiments were conducted in 2 circumneutral lakes with different acidification histories. A reciprocal transplant field enclosure experiment was conducted to assess whether the zooplankton community within the acid-recovering boreal shield lake showed evidence of increased acid tolerance to historical acidification following a 6 year period in which the lake's pH was 6.0. The enclosures were filled with epilimnetic water from the lake. Zooplankton from other lakes in the area were used. Zooplankton and water samples were collected from the enclosures once a week. Shannon-Wiener indices, species richness, and total abundance of the zooplankton were calculated for each sample day. Repeated measures analyses of variance (RM-ANOVAs) were used to test for the effects of the incubation lake, the zooplankton source, and the pH. Species abundance data were log{sub 10} transformed to improve homogeneity of variances and normality. Principle components analysis was conducted on species abundances to infer the influence of treatments on zooplankton community composition. Zooplankton were also transferred from 1 lake to the other in order to determine if subtle differences in local water chemistry and food conditions were limiting the recovery of species in acid-recovering lakes. The study showed that 2 key species, H. gibberum and L. minutus, contributed to community-level differences to acid tolerance of zooplankton with different acidification histories. It was concluded that zooplankton with adaptable acid tolerances may monopolize resources in acidified and acid-recovering lakes, and may contribute to the delayed recolonization of other taxa. 62 refs., 3 tabs., 6 figs.

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

Transformation of organic matter and the emissions of methane and ammonia during storage of liquid manure as affected by acidification

DEFF Research Database (Denmark)

Sommer, Sven G.; Clough, Timothy J.; Balaine, Nimlesh

2017-01-01

), suggesting that DOC may be a predictor for CH4 emission from dilute slurries. volatile fatty acid and total ammoniacal nitrogen concentrations in surface layers were substantially higher than at the center of stored liquid manure, perhaps resulting from microbial activity at the surface. This pattern......Acidification of livestock manure can reduce emission of the greenhouse gases methane (CH4) and nitrous oxide (N2O), as well as ammonia (NH3). We examined the relation between emission of these gases and transformation of organic matter as affected by acidification. Liquid cattle manure......, probably due to the absence of a surface crust. Reductions in NH3 and CH4 emission were highest at the start but declined over time concomitantly with a gradual increase in the stored liquid manure pH. Acidification did not significantly affect CO2 emissions. Emission of CO2 was high, fiveto ten-fold of CH...

Chemical composition of the Tatra Mountain lakes: Response to acidification

Czech Academy of Sciences Publication Activity Database

Stuchlík, E.; Kopáček, Jiří; Fott, J.; Hořická, Z.

2006-01-01

Roč. 61, Suppl. 18 (2006), S11-S20 ISSN 0006-3088 Grant - others:EC(XE) GOCE-CT-2003-505540; EC(XE) EV5V-CT92-0205 Institutional research plan: CEZ:AV0Z60170517 Keywords : acidification * long-term trends * nutrients Subject RIV: DJ - Water Pollution ; Quality Impact factor: 0.213, year: 2006

Ocean Acidification

Science.gov (United States)

Ocean and coastal acidification is an emerging issue caused by increasing amounts of carbon dioxide being absorbed by seawater. Changing seawater chemistry impacts marine life, ecosystem services, and humans. Learn what EPA is doing and what you can do.

How ocean acidification can benefit calcifiers.

Science.gov (United States)

Connell, Sean D; Doubleday, Zoë A; Hamlyn, Sarah B; Foster, Nicole R; Harley, Christopher D G; Helmuth, Brian; Kelaher, Brendan P; Nagelkerken, Ivan; Sarà, Gianluca; Russell, Bayden D

2017-02-06

Reduction in seawater pH due to rising levels of anthropogenic carbon dioxide (CO 2 ) in the world's oceans is a major force set to shape the future of marine ecosystems and the ecological services they provide [1,2]. In particular, ocean acidification is predicted to have a detrimental effect on the physiology of calcifying organisms [3]. Yet, the indirect effects of ocean acidification on calcifying organisms, which may counter or exacerbate direct effects, is uncertain. Using volcanic CO 2 vents, we tested the indirect effects of ocean acidification on a calcifying herbivore (gastropod) within the natural complexity of an ecological system. Contrary to predictions, the abundance of this calcifier was greater at vent sites (with near-future CO 2 levels). Furthermore, translocation experiments demonstrated that ocean acidification did not drive increases in gastropod abundance directly, but indirectly as a function of increased habitat and food (algal biomass). We conclude that the effect of ocean acidification on algae (primary producers) can have a strong, indirect positive influence on the abundance of some calcifying herbivores, which can overwhelm any direct negative effects. This finding points to the need to understand ecological processes that buffer the negative effects of environmental change. Copyright © 2017 Elsevier Ltd. All rights reserved.

Indicators: Acidification

Science.gov (United States)

Acidification is a broad term that refers to the process by which aquatic ecosystems become more acidic. Acid rain and acid mine drainage are major sources of acidifying compounds, lowering the pH below the range where most living organisms function.

Calcifying invertebrates succeed in a naturally CO2-rich coastal habitat but are threatened by high levels of future acidification

Directory of Open Access Journals (Sweden)

M. Wahl

2010-11-01

Full Text Available CO2 emissions are leading to an acidification of the oceans. Predicting marine community vulnerability towards acidification is difficult, as adaptation processes cannot be accounted for in most experimental studies. Naturally CO2 enriched sites thus can serve as valuable proxies for future changes in community structure. Here we describe a natural analogue site in the Western Baltic Sea. Seawater pCO2 in Kiel Fjord is elevated for large parts of the year due to upwelling of CO2 rich waters. Peak pCO2 values of >230 Pa (>2300 μatm and pHNBS values of pCO2 values are ~70 Pa (~700 μatm. In contrast to previously described naturally CO2 enriched sites that have suggested a progressive displacement of calcifying auto- and heterotrophic species, the macrobenthic community in Kiel Fjord is dominated by calcifying invertebrates. We show that blue mussels from Kiel Fjord can maintain control rates of somatic and shell growth at a pCO2 of 142 Pa (1400 μatm, pHNBS = 7.7. Juvenile mussel recruitment peaks during the summer months, when high water pCO2 values of ~100 Pa (~1000 μatm prevail. Our findings indicate that calcifying keystone species may be able to cope with surface ocean pHNBS values projected for the end of this century when food supply is sufficient. However, owing to non-linear synergistic effects of future acidification and upwelling of corrosive water, peak seawater pCO2 in Kiel Fjord and many other productive estuarine habitats could increase to values >400 Pa (>4000 μatm. These changes will most likely affect calcification and recruitment, and increase external shell dissolution.

Surface Water & Surface Drainage

Data.gov (United States)

Earth Data Analysis Center, University of New Mexico — This data set contains boundaries for all surface water and surface drainage for the state of New Mexico. It is in a vector digital data structure digitized from a...

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

Science.gov (United States)

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

Vegetation and acidification, Chapter 5

Science.gov (United States)

David R. DeWalle; James N. Kochenderfer; Mary Beth Adams; Gary W. Miller

2006-01-01

In this chapter, the impact of watershed acidification treatments on WS3 at the Fernow Experimental Forest (FEF) and at WS9 on vegetation is presented and summarized in a comprehensive way for the first time. WS7 is used as a vegetative reference basin for WS3, while untreated plots within WS9 are used as a vegetative reference for WS9. Bioindicators of acidification...

Metal concentrations in aquatic macrophytes as influenced by soil and acidification

Science.gov (United States)

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.

Vulnerability of a semienclosed estuarine sea to ocean acidification in contrast with hypoxia

Science.gov (United States)

Ianson, Debby; Allen, Susan E.; Moore-Maley, Benjamin L.; Johannessen, Sophia C.; Macdonald, Robie W.

2016-06-01

The Strait of Georgia (SoG) is a large semienclosed estuary that spatially dominates the Salish Sea on the North American Pacific coast. The region is well populated, harbors significant aquaculture, and is vulnerable to climate change. We present the first inorganic carbon data collected in the SoG covering all seasons (2003 and 2010-2012) and put them into the context of local circulation and oxygen cycles. Results show that the SoG has a higher carbon content and lower pH than surrounding waters. Aragonite saturation horizons in the SoG do not become deeper than 20-30 m and shoal to the surface for extended periods. Furthermore, incoming upwelled "acidified" water from the outer coast actually increases local pH. Finally, intense mixing in the physically restricted channels connecting the SoG to the outer coast allows significant oxygen uptake but minimal CO2 out gassing, protecting the SoG from hypoxia but not from ocean acidification.

Persistent natural acidification drives major distribution shifts in marine benthic ecosystems

Science.gov (United States)

Linares, C.; Vidal, M.; Canals, M.; Kersting, D. K.; Amblas, D.; Aspillaga, E.; Cebrián, E.; Delgado-Huertas, A.; Díaz, D.; Garrabou, J.; Hereu, B.; Navarro, L.; Teixidó, N.; Ballesteros, E.

2015-01-01

Ocean acidification is receiving increasing attention because of its potential to affect marine ecosystems. Rare CO2 vents offer a unique opportunity to investigate the response of benthic ecosystems to acidification. However, the benthic habitats investigated so far are mainly found at very shallow water (less than or equal to 5 m depth) and therefore are not representative of the broad range of continental shelf habitats. Here, we show that a decrease from pH 8.1 to 7.9 observed in a CO2 vent system at 40 m depth leads to a dramatic shift in highly diverse and structurally complex habitats. Forests of the kelp Laminaria rodriguezii usually found at larger depths (greater than 65 m) replace the otherwise dominant habitats (i.e. coralligenous outcrops and rhodolith beds), which are mainly characterized by calcifying organisms. Only the aragonite-calcifying algae are able to survive in acidified waters, while high-magnesium-calcite organisms are almost completely absent. Although a long-term survey of the venting area would be necessary to fully understand the effects of the variability of pH and other carbonate parameters over the structure and functioning of the investigated mesophotic habitats, our results suggest that in addition of significant changes at species level, moderate ocean acidification may entail major shifts in the distribution and dominance of key benthic ecosystems at regional scale, which could have broad ecological and socio-economic implications. PMID:26511045

Coral Carbonic Anhydrases: Regulation by Ocean Acidification.

Science.gov (United States)

Zoccola, Didier; Innocenti, Alessio; Bertucci, Anthony; Tambutté, Eric; Supuran, Claudiu T; Tambutté, Sylvie

2016-06-03

Global change is a major threat to the oceans, as it implies temperature increase and acidification. Ocean acidification (OA) involving decreasing pH and changes in seawater carbonate chemistry challenges the capacity of corals to form their skeletons. Despite the large number of studies that have investigated how rates of calcification respond to ocean acidification scenarios, comparatively few studies tackle how ocean acidification impacts the physiological mechanisms that drive calcification itself. The aim of our paper was to determine how the carbonic anhydrases, which play a major role in calcification, are potentially regulated by ocean acidification. For this we measured the effect of pH on enzyme activity of two carbonic anhydrase isoforms that have been previously characterized in the scleractinian coral Stylophora pistillata. In addition we looked at gene expression of these enzymes in vivo. For both isoforms, our results show (1) a change in gene expression under OA (2) an effect of OA and temperature on carbonic anhydrase activity. We suggest that temperature increase could counterbalance the effect of OA on enzyme activity. Finally we point out that caution must, thus, be taken when interpreting transcriptomic data on carbonic anhydrases in ocean acidification and temperature stress experiments, as the effect of these stressors on the physiological function of CA will depend both on gene expression and enzyme activity.

Coral Carbonic Anhydrases: Regulation by Ocean Acidification

Directory of Open Access Journals (Sweden)

Didier Zoccola

2016-06-01

Full Text Available Global change is a major threat to the oceans, as it implies temperature increase and acidification. Ocean acidification (OA involving decreasing pH and changes in seawater carbonate chemistry challenges the capacity of corals to form their skeletons. Despite the large number of studies that have investigated how rates of calcification respond to ocean acidification scenarios, comparatively few studies tackle how ocean acidification impacts the physiological mechanisms that drive calcification itself. The aim of our paper was to determine how the carbonic anhydrases, which play a major role in calcification, are potentially regulated by ocean acidification. For this we measured the effect of pH on enzyme activity of two carbonic anhydrase isoforms that have been previously characterized in the scleractinian coral Stylophora pistillata. In addition we looked at gene expression of these enzymes in vivo. For both isoforms, our results show (1 a change in gene expression under OA (2 an effect of OA and temperature on carbonic anhydrase activity. We suggest that temperature increase could counterbalance the effect of OA on enzyme activity. Finally we point out that caution must, thus, be taken when interpreting transcriptomic data on carbonic anhydrases in ocean acidification and temperature stress experiments, as the effect of these stressors on the physiological function of CA will depend both on gene expression and enzyme activity.

Contrasting chemical response to artificial acidification of three acid-sensitive streams in Maine, USA

International Nuclear Information System (INIS)

Goss, Heather V.; Norton, Stephen A.

2008-01-01

We experimentally acidified three low alkalinity first-order streams in forested catchments in Maine, USA. We evaluated water samples from a reference site above the point of hydrochloric acid addition and from two or three sites located 16 to 94 m downstream. Neutralization included protonation of weak acids, adsorption of sulfate, and ion exchange of base cations and aluminum (Al) for protons (H + ). Protonation of bicarbonate was significant in the relatively high pH Hadlock Brook. Protonation of weak organic acids dominated in the high dissolved organic carbon (DOC) Mud Pond Inlet. The response in low DOC, low pH East Bear Brook was dominated by stream substrate release of cations. East Bear Brook had the strongest acid neutralization response per unit catchment area. In all streams, exchangeable calcium (Ca) and magnesium (Mg) were mobilized, with Ca > Mg. Al was also mobilized. During initial stages of acidification, Ca desorbed preferentially, whereas Al mobilization dominated later. Early in the recovery, adsorption of Ca to the streambed sediments was kinetically favored over adsorption of Al. Though pH increased downstream of acid addition, the streams remained undersaturated with respect to amorphous Al(OH) 3 , so Al did not precipitate. In East Bear Brook, however, Al left solution further downstream through adsorption. This process was likely kinetically controlled, because it occurred in East Bear Brook (3-4 L/s) but did not occur in Hadlock Brook (ca. 40 L/s) or Mud Pond Inlet (ca. 60 L/s). During experimental acidification, the initial Al:Ca ratio of a stream's response may indicate the acidification status of the catchment. Short-term stream acidification experiments illuminate processes characteristic of episodic stream acidification and of long-term catchment acidification. East Bear Brook and Hadlock Brook catchments are in early to intermediate stages of acidification. The Mud Pond Inlet catchment (high Al:Ca ratio) is in a later stage of

Geobiological Responses to Ocean Acidification

Science.gov (United States)

Potts, D. C.

2008-12-01

During 240Ma of evolution, scleractinian corals survived major changes in ocean chemistry, yet recent concerns with rapid acidification after ca. 40Ma of almost constant oceanic pH have tended to distract attention from natural pH variation in coastal waters, where most corals and reefs occur. Unaltered skeletal environmental proxies reflect conditions experienced by individual organisms, with any variation on micro- habitat and micro-time scales appropriate for that individual's ecology, behavior and physiology, but proxy interpretation usually extrapolates to larger spatial (habitat, region to global) and temporal (seasonal, annual, interannual) scales. Therefore, predicting consequences of acidification for both corals and reefs requires greater understanding of: 1. Many potential indirect consequences of pH change that may affect calcification and/or carbonate accretion: e.g. an individual's developmental rates, growth, final size, general physiology and reproductive success; its population's distribution and abundance, symbionts, food availability, predators and pathogens; and its community and ecosystem services. 2. Potentially diverse responses to declining pH, ranging from non-evolutionary, rapid physiological changes (acclimation) or long term (seasonal to interannual) plasticity (acclimatization) of individuals, through genetic adaptation in local populations, and up to directional changes in species" characteristics and/or radiations/extinctions. 3. The evolutionary and environmental history of an organism's lineage, its ecological (own lifetime) exposure to environmental variation, and "pre-adaptation" via other factors acting on correlated characters.

Optogenetic acidification of synaptic vesicles and lysosomes.

Science.gov (United States)

Rost, Benjamin R; Schneider, Franziska; Grauel, M Katharina; Wozny, Christian; Bentz, Claudia; Blessing, Anja; Rosenmund, Tanja; Jentsch, Thomas J; Schmitz, Dietmar; Hegemann, Peter; Rosenmund, Christian

2015-12-01

Acidification is required for the function of many intracellular organelles, but methods to acutely manipulate their intraluminal pH have not been available. Here we present a targeting strategy to selectively express the light-driven proton pump Arch3 on synaptic vesicles. Our new tool, pHoenix, can functionally replace endogenous proton pumps, enabling optogenetic control of vesicular acidification and neurotransmitter accumulation. Under physiological conditions, glutamatergic vesicles are nearly full, as additional vesicle acidification with pHoenix only slightly increased the quantal size. By contrast, we found that incompletely filled vesicles exhibited a lower release probability than full vesicles, suggesting preferential exocytosis of vesicles with high transmitter content. Our subcellular targeting approach can be transferred to other organelles, as demonstrated for a pHoenix variant that allows light-activated acidification of lysosomes.

Next-century ocean acidification and warming both reduce calcification rate, but only acidification alters skeletal morphology of reef-building coral Siderastrea siderea.

Science.gov (United States)

Horvath, Kimmaree M; Castillo, Karl D; Armstrong, Pualani; Westfield, Isaac T; Courtney, Travis; Ries, Justin B

2016-07-29

Atmospheric pCO2 is predicted to rise from 400 to 900 ppm by year 2100, causing seawater temperature to increase by 1-4 °C and pH to decrease by 0.1-0.3. Sixty-day experiments were conducted to investigate the independent and combined impacts of acidification (pCO2 = 424-426, 888-940 ppm-v) and warming (T = 28, 32 °C) on calcification rate and skeletal morphology of the abundant and widespread Caribbean reef-building scleractinian coral Siderastrea siderea. Hierarchical linear mixed-effects modelling reveals that coral calcification rate was negatively impacted by both warming and acidification, with their combined effects yielding the most deleterious impact. Negative effects of warming (32 °C/424 ppm-v) and high-temperature acidification (32 °C/940 ppm-v) on calcification rate were apparent across both 30-day intervals of the experiment, while effects of low-temperature acidification (28 °C/888 ppm-v) were not apparent until the second 30-day interval-indicating delayed onset of acidification effects at lower temperatures. Notably, two measures of coral skeletal morphology-corallite height and corallite infilling-were negatively impacted by next-century acidification, but not by next-century warming. Therefore, while next-century ocean acidification and warming will reduce the rate at which corals build their skeletons, next-century acidification will also modify the morphology and, potentially, function of coral skeletons.

Surface-water surveillance

Energy Technology Data Exchange (ETDEWEB)

Saldi, K.A.; Dirkes, R.L.; Blanton, M.L.

1995-06-01

This section of the 1994 Hanford Site Environmental Report summarizes the Surface water on and near the Hanford Site is monitored to determine the potential effects of Hanford operations. Surface water at Hanford includes the Columbia River, riverbank springs, ponds located on the Hanford Site, and offsite water systems directly east and across the Columbia River from the Hanford Site, and offsite water systems directly east and across the Columbia River from the Hanford Site. Columbia River sediments are also included in this discussion. Tables 5.3.1 and 5.3.2 summarize the sampling locations, sample types, sampling frequencies, and sample analyses included in surface-water surveillance activities during 1994. Sample locations are also identified in Figure 5.3.1. This section describes the surveillance effort and summarizes the results for these aquatic environments. Detailed analytical results are reported by Bisping (1995).

Surface-water surveillance

International Nuclear Information System (INIS)

Saldi, K.A.; Dirkes, R.L.; Blanton, M.L.

1995-01-01

This section of the 1994 Hanford Site Environmental Report summarizes the Surface water on and near the Hanford Site is monitored to determine the potential effects of Hanford operations. Surface water at Hanford includes the Columbia River, riverbank springs, ponds located on the Hanford Site, and offsite water systems directly east and across the Columbia River from the Hanford Site, and offsite water systems directly east and across the Columbia River from the Hanford Site. Columbia River sediments are also included in this discussion. Tables 5.3.1 and 5.3.2 summarize the sampling locations, sample types, sampling frequencies, and sample analyses included in surface-water surveillance activities during 1994. Sample locations are also identified in Figure 5.3.1. This section describes the surveillance effort and summarizes the results for these aquatic environments. Detailed analytical results are reported by Bisping (1995)

Spatial aspects affecting acidification factors in European acidification modelling

NARCIS (Netherlands)

Bellekom, S.; Hettelingh, J. -P.; Aben, J.

Plain linear models have recently been used in methodologies to model fate and transport for assessing acidification in life cycle impact assessment (LCIA), or in support of air pollution abatement policies. These models originate from a statistical analysis of the relationship between inputs and

Water at surfaces with tunable surface chemistries

Science.gov (United States)

Sanders, Stephanie E.; Vanselous, Heather; Petersen, Poul B.

2018-03-01

Aqueous interfaces are ubiquitous in natural environments, spanning atmospheric, geological, oceanographic, and biological systems, as well as in technical applications, such as fuel cells and membrane filtration. Where liquid water terminates at a surface, an interfacial region is formed, which exhibits distinct properties from the bulk aqueous phase. The unique properties of water are governed by the hydrogen-bonded network. The chemical and physical properties of the surface dictate the boundary conditions of the bulk hydrogen-bonded network and thus the interfacial properties of the water and any molecules in that region. Understanding the properties of interfacial water requires systematically characterizing the structure and dynamics of interfacial water as a function of the surface chemistry. In this review, we focus on the use of experimental surface-specific spectroscopic methods to understand the properties of interfacial water as a function of surface chemistry. Investigations of the air-water interface, as well as efforts in tuning the properties of the air-water interface by adding solutes or surfactants, are briefly discussed. Buried aqueous interfaces can be accessed with careful selection of spectroscopic technique and sample configuration, further expanding the range of chemical environments that can be probed, including solid inorganic materials, polymers, and water immiscible liquids. Solid substrates can be finely tuned by functionalization with self-assembled monolayers, polymers, or biomolecules. These variables provide a platform for systematically tuning the chemical nature of the interface and examining the resulting water structure. Finally, time-resolved methods to probe the dynamics of interfacial water are briefly summarized before discussing the current status and future directions in studying the structure and dynamics of interfacial water.

Soil acidification: its extent, development during the last decades, and causes

International Nuclear Information System (INIS)

Hildebrand, E.E.

1989-01-01

During the last decades there has been substantially increasing, extended forest soil acidity in central Europe. The higher the previous saturation in bases had been, the more pronounced was the loss in neutralization capacity. In many northern and central European sites, the rate of protons carried in by wet deposition already exceeds the rate of bases from the soil's buffer activity and from silicate degradation. The resulting, lower pH is buffered by protolysis of Al and Fe oxides. This makes Al the dominant cation in many sites, whose toxicity for forest ecosystems is critically discussed. A part from atmospheric acid deposition, high production and exports of biomass are also liable to cause heavy surface soil acidification locally, but the two types of deposition are basically different. Whereas acidification by organic acids from biomass is restricted to the area between the organic cover layer and the Bh layer, acidification from the deposition of permanently loaded mineral acid anions penetrates beyond the rhizosphere into the C layer and aquifers, endangering the hydrosphere as well. Therefore, the buffering properties of the lithosphere acquire increasing importance. (orig./vhe) [de

Surface freezing of water

OpenAIRE

P?rez-D?az, J. L.; ?lvarez-Valenzuela, M. A.; Rodr?guez-Celis, F.

2016-01-01

Freezing, melting, evaporation and condensation of water are essential ingredients for climate and eventually life on Earth. In the present work, we show how surface freezing of supercooled water in an open container is conditioned and triggered?exclusively?by humidity in air. Additionally, a change of phase is demonstrated to be triggered on the water surface forming surface ice crystals prior to freezing of bulk. The symmetry of the surface crystal, as well as the freezing point, depend on ...

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

Science.gov (United States)

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 (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

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.

Science.gov (United States)

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.

Individual and population-level responses to ocean acidification.

Science.gov (United States)

Harvey, Ben P; McKeown, Niall J; Rastrick, Samuel P S; Bertolini, Camilla; Foggo, Andy; Graham, Helen; Hall-Spencer, Jason M; Milazzo, Marco; Shaw, Paul W; Small, Daniel P; Moore, Pippa J

2016-01-29

Ocean acidification is predicted to have detrimental effects on many marine organisms and ecological processes. Despite growing evidence for direct impacts on specific species, few studies have simultaneously considered the effects of ocean acidification on individuals (e.g. consequences for energy budgets and resource partitioning) and population level demographic processes. Here we show that ocean acidification increases energetic demands on gastropods resulting in altered energy allocation, i.e. reduced shell size but increased body mass. When scaled up to the population level, long-term exposure to ocean acidification altered population demography, with evidence of a reduction in the proportion of females in the population and genetic signatures of increased variance in reproductive success among individuals. Such increased variance enhances levels of short-term genetic drift which is predicted to inhibit adaptation. Our study indicates that even against a background of high gene flow, ocean acidification is driving individual- and population-level changes that will impact eco-evolutionary trajectories.

Evaluation of different approaches to quantify strong organic acidity and acid-base buffering of organic-rich surface waters in Sweden.

Science.gov (United States)

Köhler, Stephan; Hruska, Jakub; Jönsson, Jörgen; Lövgren, Lars; Lofts, Stephen

2002-11-01

The role of organic acids in buffering pH in surface waters has been studied using a small brownwater stream (26mg L(-1) TOC) draining a forested catchment in Northern Sweden. Under the conditions of elevated pressure of CO2 stream field pH was changed between 3.5 and 6.1 during the acidification and alkalinization experiment. Acid-base characteristics of the natural organic matter were also determined using a high precision potentiometric method for a concentrated sample from the same stream. We compared the predictions from the Windermere Humic Aqueous Model (WHAM Model V), a model derived from the potentiometric titration (diprotic/monoprotic acid model) and a previously derived triprotic acid model which only uses alkalinity and TOC as input variables. The predicted buffering characteristics of all three models are very similar in the pH range 4.5-7 which suggests that during routine analysis alkalinity and TOC are sufficient to give a good estimate of organic acid anion charge contribution in a large range of surface waters. A slightly adjusted version of WHAM V successfully describes the organic charge contribution in a large number of sampled surface water lakes, which were previously used to calibrate the triprotic model.

Coral calcifying fluid pH dictates response to ocean acidification.

Science.gov (United States)

Holcomb, M; Venn, A A; Tambutté, E; Tambutté, S; Allemand, D; Trotter, J; McCulloch, M

2014-06-06

Ocean acidification driven by rising levels of CO2 impairs calcification, threatening coral reef growth. Predicting how corals respond to CO2 requires a better understanding of how calcification is controlled. Here we show how spatial variations in the pH of the internal calcifying fluid (pHcf) in coral (Stylophora pistillata) colonies correlates with differential sensitivity of calcification to acidification. Coral apexes had the highest pHcf and experienced the smallest changes in pHcf in response to acidification. Lateral growth was associated with lower pHcf and greater changes with acidification. Calcification showed a pattern similar to pHcf, with lateral growth being more strongly affected by acidification than apical. Regulation of pHcf is therefore spatially variable within a coral and critical to determining the sensitivity of calcification to ocean acidification.

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

Directory of Open Access Journals (Sweden)

Sue-Ann Watson

Full Text Available 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.

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

Science.gov (United States)

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.

Surface freezing of water.

Science.gov (United States)

Pérez-Díaz, J L; Álvarez-Valenzuela, M A; Rodríguez-Celis, F

2016-01-01

Freezing, melting, evaporation and condensation of water are essential ingredients for climate and eventually life on Earth. In the present work, we show how surface freezing of supercooled water in an open container is conditioned and triggered-exclusively-by humidity in air. Additionally, a change of phase is demonstrated to be triggered on the water surface forming surface ice crystals prior to freezing of bulk. The symmetry of the surface crystal, as well as the freezing point, depend on humidity, presenting at least three different types of surface crystals. Humidity triggers surface freezing as soon as it overpasses a defined value for a given temperature, generating a plurality of nucleation nodes. An evidence of simultaneous nucleation of surface ice crystals is also provided.

Ocean acidification genetics - Genetics and genomics of response to ocean acidification

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — We are applying a variety of genetic tools to assess the response of our ocean resources to ocean acidification, including gene expression techniques, identification...

Climate change impact on future ocean acidification

International Nuclear Information System (INIS)

McNeil, Ben

2007-01-01

Full text: Elevated atmospheric C02 levels and associated uptake by the ocean is changing its carbon chemistry, leading to an acidification. The implications of future ocean acidification on the marine ecosystem are unclear but seemingly detrimental particularly to those organisms and phytoplankton that secrete calcium carbonate (like corals). Here we present new results from the Australian CSIRO General Circulation Model that predicts the changing nature of oceanic carbon chemistry in response to future climate change feedbacks (circulation, temperature and biological). We will discuss the implications of future ocean acidification and the potential implications on Australia's marine ecosystems

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

Science.gov (United States)

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).

Will PM control undermine China's efforts to reduce soil acidification?

International Nuclear Information System (INIS)

Zhao Yu; Duan Lei; Lei Yu; Xing Jia; Nielsen, Chris P.; Hao Jiming

2011-01-01

China's strategies to control acidifying pollutants and particulate matter (PM) may be in conflict for soil acidification abatement. Acidifying pollutant emissions are estimated for 2005 and 2020 with anticipated control policies. PM emissions including base cations (BCs) are evaluated with two scenarios, a base case applying existing policy to 2020, and a control case including anticipated tightened measures. Depositions of sulfur (S), nitrogen (N) and BCs are simulated and their acidification risks are evaluated with critical load (CL). In 2005, the area exceeding CL covered 15.6% of mainland China, with total exceedance of 2.2 Mt S. These values decrease in the base scenario 2020, implying partial recovery from acidification. Under more realistic PM control, the respective estimates are 17.9% and 2.4 Mt S, indicating increased acidification risks due to abatement of acid-neutralizing BCs. China's anthropogenic PM abatement will have potentially stronger chemical implications for acidification than developed countries. - Highlights: → We model the emission and deposition of base cations and acid precursors in China. → Soil acidification in China is analyzed with exceedance of critical load. → China's PM control increases the acidification risk even with reduced SO 2 emission. → The impact of PM for acidification is stronger than that in developed countries. - The control of anthropogenic PM emission in China will increase the risk of soil acidification even with reduced SO 2 emission. Such implication is stronger than that in developed countries.

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

Science.gov (United States)

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

Influence of ocean acidification and deep water upwelling on oligotrophic plankton communities in the subtropical North Atlantic

DEFF Research Database (Denmark)

Taucher, Jan; Bach, Lennart T.; Boxhammer, Tim

2017-01-01

Oceanic uptake of anthropogenic carbon dioxide (CO2) causes pronounced shifts in marine carbonate chemistry and a decrease in seawater pH. Increasing evidence indicates that these changes-summarized by the term ocean acidification (OA)-can significantly affect marine food webs and biogeochemical...... cycles. However, current scientific knowledge is largely based on laboratory experiments with single species and artificial boundary conditions, whereas studies of natural plankton communities are still relatively rare. Moreover, the few existing community-level studies were mostly conducted in rather...... and successfully simulated a deep water upwelling event that induced a pronounced plankton bloom. Our study revealed significant effects of OA on the entire food web, leading to a restructuring of plankton communities that emerged during the oligotrophic phase, and was further amplified during the bloom...

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

Science.gov (United States)

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

Integrating microbial fuel cells with anaerobic acidification and forward osmosis membrane for enhancing bio-electricity and water recovery from low-strength wastewater.

Science.gov (United States)

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.

A novel marine mesocosm facility to study global warming, water quality, and ocean acidification.

Science.gov (United States)

Duarte, Gustavo; Calderon, Emiliano N; Pereira, Cristiano M; Marangoni, Laura F B; Santos, Henrique F; Peixoto, Raquel S; Bianchini, Adalto; Castro, Clovis B

2015-10-01

We describe a completely randomizable flow-through outdoor mesocosm for climate change and ecotoxicology studies that was built with inexpensive materials. The 16 raceway tanks allow up to 6× water renewal per hour, avoiding changes in natural abiotic seawater conditions. We use an open-source hardware board (Arduino) that was adapted to control heaters and an innovative CO 2 injection system. This system reduced seawater pH up to -0.9 units and increased temperature up to +6°C in three treatments and a control. Treatments can be continuously compared with the control and vary according to diel fluctuations, thus following the diel range observed in the sea. The mesocosm facility also includes an integrated secondary system of 48 aquaria for ecotoxicology studies. We validated the reproducibility and relevance of our experimental system by analyzing the variation of the total DNA of the microbial community extracted from corals in three elevated temperature scenarios during a 40-day experiment. We also present data from temperature, acidification, and copper contamination trials, which allowed continuous, reliable, and consistent treatment manipulations.

Investigating Undergraduate Science Students’ Conceptions and Misconceptions of Ocean Acidification

Science.gov (United States)

Danielson, Kathryn I.; Tanner, Kimberly D.

2015-01-01

Scientific research exploring ocean acidification has grown significantly in past decades. However, little science education research has investigated the extent to which undergraduate science students understand this topic. Of all undergraduate students, one might predict science students to be best able to understand ocean acidification. What conceptions and misconceptions of ocean acidification do these students hold? How does their awareness and knowledge compare across disciplines? Undergraduate biology, chemistry/biochemistry, and environmental studies students, and science faculty for comparison, were assessed on their awareness and understanding. Results revealed low awareness and understanding of ocean acidification among students compared with faculty. Compared with biology or chemistry/biochemistry students, more environmental studies students demonstrated awareness of ocean acidification and identified the key role of carbon dioxide. Novel misconceptions were also identified. These findings raise the question of whether undergraduate science students are prepared to navigate socioenvironmental issues such as ocean acidification. PMID:26163563

Decreased DOC concentrations in soil water in forested areas in southern Sweden during 1987-2008.

Science.gov (United States)

Löfgren, Stefan; Zetterberg, Therese

2011-04-15

During the last two decades, there is a common trend of increasing concentrations of dissolved organic carbon (DOC) in streams and lakes in Europe, Canada and the US. Different processes have been proposed to explain this trend and recently a unifying hypothesis was presented, concluding that declining sulphur deposition and recovery from acidification, is the single most important factor for the long-term DOC concentration trends in surface waters. If this recovery hypothesis is correct, the soil water DOC concentrations should increase as well. However, long-term soil water data from Sweden and Norway indicate that there are either decreasing or indifferent DOC concentrations, while positive DOC trends have been found in the Czech Republic. Based on the soil water data from two Swedish integrated monitoring sites and geochemical modelling, it has been shown that depending on changes in pH, ionic strength and soil Al pools, the DOC solubility might be positive, negative or indifferent. In this study, we test the acidification recovery hypothesis on long-term soil water data (25 and 50cm soil depth) from 68 forest covered sites in southern Sweden, showing clear signs of recovery from acidification. The main aim was to identify potential drivers for the DOC solubility in soil solution by comparing trends in DOC concentrations with observed changes in pH, ionic strength and concentrations of Al(n+). As in earlier Swedish and Norwegian studies, the DOC concentrations in soil water decreased or showed no trend. The generally small increases in pH (median <0.3 pH units) during the investigation period seem to be counterbalanced by the reduced ionic strength and diminished Al concentrations, increasing the organic matter coagulation. Hence, opposite to the conclusion for surface waters, the solubility of organic matter seems to decrease in uphill soils, as a result of the acidification recovery. Copyright © 2011 Elsevier B.V. All rights reserved.

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

Science.gov (United States)

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

Vulnerability and adaptation of US shellfisheries to ocean acidification

Science.gov (United States)

Ekstrom, Julia A.; Suatoni, Lisa; Cooley, Sarah R.; Pendleton, Linwood H.; Waldbusser, George G.; Cinner, Josh E.; Ritter, Jessica; Langdon, Chris; van Hooidonk, Ruben; Gledhill, Dwight; Wellman, Katharine; Beck, Michael W.; Brander, Luke M.; Rittschof, Dan; Doherty, Carolyn; Edwards, Peter E. T.; Portela, Rosimeiry

2015-03-01

Ocean acidification is a global, long-term problem whose ultimate solution requires carbon dioxide reduction at a scope and scale that will take decades to accomplish successfully. Until that is achieved, feasible and locally relevant adaptation and mitigation measures are needed. To help to prioritize societal responses to ocean acidification, we present a spatially explicit, multidisciplinary vulnerability analysis of coastal human communities in the United States. We focus our analysis on shelled mollusc harvests, which are likely to be harmed by ocean acidification. Our results highlight US regions most vulnerable to ocean acidification (and why), important knowledge and information gaps, and opportunities to adapt through local actions. The research illustrates the benefits of integrating natural and social sciences to identify actions and other opportunities while policy, stakeholders and scientists are still in relatively early stages of developing research plans and responses to ocean acidification.

Effects of ocean acidification on the dissolution rates of reef-coral skeletons

Directory of Open Access Journals (Sweden)

Robert van Woesik

2013-11-01

Full Text Available 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.

Ocean Acidification

Science.gov (United States)

Ludwig, Claudia; Orellana, Mónica V.; DeVault, Megan; Simon, Zac; Baliga, Nitin

2015-01-01

The curriculum module described in this article addresses the global issue of ocean acidification (OA) (Feely 2009; Figure 1). OA is a harmful consequence of excess carbon dioxide (CO[subscript 2]) in the atmosphere and poses a threat to marine life, both algae and animal. This module seeks to teach and help students master the cross-disciplinary…

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

Science.gov (United States)

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.

Sustaining dry surfaces under water

DEFF Research Database (Denmark)

Jones, Paul R.; Hao, Xiuqing; Cruz-Chu, Eduardo R.

2015-01-01

Rough surfaces immersed under water remain practically dry if the liquid-solid contact is on roughness peaks, while the roughness valleys are filled with gas. Mechanisms that prevent water from invading the valleys are well studied. However, to remain practically dry under water, additional...... mechanisms need consideration. This is because trapped gas (e.g. air) in the roughness valleys can dissolve into the water pool, leading to invasion. Additionally, water vapor can also occupy the roughness valleys of immersed surfaces. If water vapor condenses, that too leads to invasion. These effects have...... not been investigated, and are critically important to maintain surfaces dry under water.In this work, we identify the critical roughness scale, below which it is possible to sustain the vapor phase of water and/or trapped gases in roughness valleys – thus keeping the immersed surface dry. Theoretical...

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

International Nuclear Information System (INIS)

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 (2.5-8.0) 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 'bio-available' 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 to 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.

Future ocean acidification in the Canada Basin and surrounding Arctic Ocean from CMIP5 earth system models

Science.gov (United States)

Steiner, N. S.; Christian, J. R.; Six, K. D.; Yamamoto, A.; Yamamoto-Kawai, M.

2014-01-01

Six Earth system models that include an interactive carbon cycle and have contributed results to the 5th Coupled Model Intercomparison Project (CMIP5) are evaluated with respect to Arctic Ocean acidification. Projections under Representative Concentration Pathways (RCPs) 8.5 and 4.5 consistently show reductions in the bidecadal mean surface pH from about 8.1 in 1986-2005 to 7.7/7.9 by 2066-2085 in the Canada Basin, closely linked to reductions in the calcium carbonate saturation state ΩA,C from about 1.4 (2.0) to 0.7 (1.0) for aragonite (calcite) for RCP8.5. The large but opposite effects of dilution and biological drawdown of DIC and dilution of alkalinity lead to a small seasonal amplitude change in Ω, as well as intermodel differences in the timing and sign of the summer minimum. The Canada Basin shows a characteristic layering in Ω: affected by ice melt and inflowing Pacific water, shallow undersaturated layers form at the surface and subsurface, creating a shallow saturation horizon which expands from the surface downward. This is in addition to the globally observed deep saturation horizon which is continuously expanding upward with increasing CO2 uptake. The Eurasian Basin becomes undersaturated much later than the rest of the Arctic. These CMIP5 model results strengthen earlier findings, although large intermodel differences remain: Below 200 m ΩA varies by up to 1.0 in the Canada Basin and the deep saturation horizon varies from 2000 to 4000 m among the models. Differences of projected acidification changes are primarily related to sea ice retreat and responses of wind mixing and stratification.

Forest land cover continues to exacerbate freshwater acidification despite decline in sulphate emissions

International Nuclear Information System (INIS)

Dunford, Robert W.; Donoghue, Daniel N.M.; Burt, Tim P.

2012-01-01

Evidence from a multi-date regional-scale analysis of both high-flow and annual-average water quality data from Galloway, south-west Scotland, demonstrates that forest land cover continues to exacerbate freshwater acidification. This is in spite of significant reductions in airborne pollutants. The relationship between freshwater sulphate and forest cover has decreased from 1996 to 2006 indicating a decrease in pollutant scavenging. The relationship between forest cover and freshwater acidity (pH) is, however, still present over the same period, and does not show conclusive signs of having declined. Furthermore, evidence for forest cover contributing to a chlorine bias in marine ion capture suggests that forest scavenging of sea-salts may mean that the forest acidification effect may continue in the absence of anthropogenic pollutant inputs, particularly in coastal areas. - Highlights: ► Forest cover and water chemistry remain linked despite decreased sulphate emissions. ► Forest cover has significant relationships SO 4 2− , Cl − , Na + , pH, ANC and Na:Cl ratio. ► Forest cover: pH relationships shows some evidence of decline 1996–2006. ► Forest cover: freshwater sulphate relationships show evidence of decline 1996–2006. ► Natural forest-mechanisms may exacerbate acidification, particularly sea-salt scavenging. - Relationships between forest land cover and freshwater pH continue to be evident despite declines in anthropogenic pollutant sulphate deposition; sea-salt scavenging may play a role.

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

Science.gov (United States)

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.

Quantifying the influence of CO2 seasonality on future ocean acidification

Science.gov (United States)

Sasse, T. P.; McNeil, B. I.; Matear, R. J.; Lenton, A.

2015-04-01

Ocean acidification is a predictable consequence of rising atmospheric carbon dioxide (CO2), and is highly likely to impact the entire marine ecosystem - from plankton at the base to fish at the top. Factors which are expected to be impacted include reproductive health, organism growth and species composition and distribution. Predicting when critical threshold values will be reached is crucial for projecting the future health of marine ecosystems and for marine resources planning and management. The impacts of ocean acidification will be first felt at the seasonal scale, however our understanding how seasonal variability will influence rates of future ocean acidification remains poorly constrained due to current model and data limitations. To address this issue, we first quantified the seasonal cycle of aragonite saturation state utilizing new data-based estimates of global ocean surface dissolved inorganic carbon and alkalinity. This seasonality was then combined with earth system model projections under different emissions scenarios (RCPs 2.6, 4.5 and 8.5) to provide new insights into future aragonite under-saturation onset. Under a high emissions scenario (RCP 8.5), our results suggest accounting for seasonality will bring forward the initial onset of month-long under-saturation by 17 years compared to annual-mean estimates, with differences extending up to 35 ± 17 years in the North Pacific due to strong regional seasonality. Our results also show large-scale under-saturation once atmospheric CO2 reaches 486 ppm in the North Pacific and 511 ppm in the Southern Ocean independent of emission scenario. Our results suggest that accounting for seasonality is critical to projecting the future impacts of ocean acidification on the marine environment.

Coral bleaching under unconventional scenarios of climate warming and ocean acidification

Science.gov (United States)

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.

Interactive Effects of Ocean Acidification and Warming on Growth, Fitness and Survival of the Cold-Water Coral Lophelia pertusa under Different Food Availabilities

Directory of Open Access Journals (Sweden)

Janina V. Büscher

2017-04-01

Full Text Available Cold-water corals are important bioengineers that provide structural habitat for a diverse species community. About 70% of the presently known scleractinian cold-water corals are expected to be exposed to corrosive waters by the end of this century due to ocean acidification. At the same time, the corals will experience a steady warming of their environment. Studies on the sensitivity of cold-water corals to climate change mainly concentrated on single stressors in short-term incubation approaches, thus not accounting for possible long-term acclimatisation and the interactive effects of multiple stressors. Besides, preceding studies did not test for possible compensatory effects of a change in food availability. In this study a multifactorial long-term experiment (6 months was conducted with end-of-the-century scenarios of elevated pCO2 and temperature levels in order to examine the acclimatisation potential of the cosmopolitan cold-water coral Lophelia pertusa to future climate change related threats. For the first time multiple ocean change impacts including the role of the nutritional status were tested on L. pertusa with regard to growth, “fitness,” and survival. Our results show that while L. pertusa is capable of calcifying under elevated CO2 and temperature, its condition (fitness is more strongly influenced by food availability rather than changes in seawater chemistry. Whereas growth rates increased at elevated temperature (+4°C, they decreased under elevated CO2 concentrations (~800 μatm. No difference in net growth was detected when corals were exposed to the combination of increased CO2 and temperature compared to ambient conditions. A 10-fold higher food supply stimulated growth under elevated temperature, which was not observed in the combined treatment. This indicates that increased food supply does not compensate for adverse effects of ocean acidification and underlines the importance of considering the nutritional status

Surface Water in Hawaii

Science.gov (United States)

Oki, Delwyn S.

2003-01-01

Surface water in Hawaii is a valued resource as well as a potential threat to human lives and property. The surface-water resources of Hawaii are of significant economic, ecologic, cultural, and aesthetic importance. Streams supply more than 50 percent of the irrigation water in Hawaii, and although streams supply only a few percent of the drinking water statewide, surface water is the main source of drinking water in some places. Streams also are a source of hydroelectric power, provide important riparian and instream habitats for many unique native species, support traditional and customary Hawaiian gathering rights and the practice of taro cultivation, and possess valued aesthetic qualities. Streams affect the physical, chemical, and aesthetic quality of receiving waters, such as estuaries, bays, and nearshore waters, which are critical to the tourism-based economy of the islands. Streams in Hawaii pose a danger because of their flashy nature; a stream's stage, or water level, can rise several feet in less than an hour during periods of intense rainfall. Streams in Hawaii are flashy because rainfall is intense, drainage basins are small, basins and streams are steep, and channel storage is limited. Streamflow generated during periods of heavy rainfall has led to loss of property and human lives in Hawaii. Most Hawaiian streams originate in the mountainous interiors of the islands and terminate at the coast. Streams are significant sculptors of the Hawaiian landscape because of the erosive power of the water they convey. In geologically young areas, such as much of the southern part of the island of Hawaii, well-defined stream channels have not developed because the permeability of the surface rocks generally is so high that rainfall infiltrates before flowing for significant distances on the surface. In geologically older areas that have received significant rainfall, streams and mass wasting have carved out large valleys.

Sensitivity of the regional ocean acidification and carbonate system in Puget Sound to ocean and freshwater inputs

Directory of Open Access Journals (Sweden)

Laura Bianucci

2018-03-01

Full Text Available While ocean acidification was first investigated as a global phenomenon, coastal acidification has received significant attention in recent years, as its impacts have been felt by different socio-economic sectors (e.g., high mortality of shellfish larvae in aquaculture farms. As a region that connects land and ocean, the Salish Sea (consisting of Puget Sound and the Straits of Juan de Fuca and Georgia receives inputs from many different sources (rivers, wastewater treatment plants, industrial waste treatment facilities, etc., making these coastal waters vulnerable to acidification. Moreover, the lowering of pH in the Northeast Pacific Ocean also affects the Salish Sea, as more acidic waters get transported into the bottom waters of the straits and estuaries. Here, we use a numerical ocean model of the Salish Sea to improve our understanding of the carbonate system in Puget Sound; in particular, we studied the sensitivity of carbonate variables (e.g., dissolved inorganic carbon, total alkalinity, pH, saturation state of aragonite to ocean and freshwater inputs. The model is an updated version of our FVCOM-ICM framework, with new carbonate-system and sediment modules. Sensitivity experiments altering concentrations at the open boundaries and freshwater sources indicate that not only ocean conditions entering the Strait of Juan de Fuca, but also the dilution of carbonate variables by freshwater sources, are key drivers of the carbonate system in Puget Sound.

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

Science.gov (United States)

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

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

Directory of Open Access Journals (Sweden)

Elizabeth Derse Crook

Full Text Available 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.

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

Science.gov (United States)

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.

Low pH Springs - A Natural Laboratory for Ocean Acidification

Science.gov (United States)

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.

Ocean Acidification Product Suite

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — Scientists within the ACCRETE (Acidification, Climate, and Coral Reef Ecosystems Team) Lab of AOML_s Ocean Chemistry and Ecosystems Division (OCED) have constructed...

Influences of riverine and upwelling waters on the coastal carbonate system off Central Chile and their ocean acidification implications

Science.gov (United States)

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

Spring flood pH decline in northern Sweden: Towards an operational model separating natural acidity from anthropogenic acidification

Energy Technology Data Exchange (ETDEWEB)

Laudon, H.

1999-10-01

The spring flood is a defining feature of the ecosystem in northern Sweden. In this region, spring flood is an occasion for dramatic hydrochemical changes that profoundly effect the biodiversity of the aquatic ecosystem. Spring flood is also the period most susceptible to anthropogenic acidification. A belief in the anthropogenic component to pH decline during spring flood has been an important factor in spending over half a billion crowns to lime surface waters in Northern Sweden during the last decade. The natural component of episodic pH decline during spring flood, however, has received less attention. The main objective of this work is to present an operational model for separating and quantifying the anthropogenic and natural contributions of episodic acidification during high flow events in Northern Sweden. The key assumptions in this model are that baseflow ANC has not been affected by anthropogenic acidification, that DOC has not changed due to modern land-use practice and that natural dilution during hydrological episodes can be quantified. The limited data requirements of 10-15 stream water samples before and during spring flood make the model suitable for widespread use in environmental monitoring programs. This makes it possible to distinguish trends of human impact as well as natural pH decline in space and time. Modeling results from northern Sweden demonstrate that the natural driving mechanisms of dilution and organic acidity were the dominant factors in the episodic acidification of spring flood in the region. The anthropogenic contribution to spring pH decline was similar in size to the natural contribution in only two of the more than 30 events where this model was applied. Natural factors alone were found to cause pH values below 4.5 in some streams. Anthropogenic sources of acidity can be superimposed on this natural dynamics. In the sites studied, the magnitude of the anthropogenic ANC decline was correlated to the winter deposition of

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

Science.gov (United States)

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.

Evaluation of episodic acidification and amphibian declines in the Rocky Mountains

Science.gov (United States)

Frank A. Vertucci; Paul Stephen Corn

1996-01-01

We define criteria for documenting episodic acidification of amphibian breeding habitats and examine whether episodic acidification is responsible for observed declines of amphibian populations in the Rocky Mountains. Anthropogenic episodic acidification, caused by atmospheric deposition of sulfate and nitrate, occurs when the concentration of acid anions increases...

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

Directory of Open Access Journals (Sweden)

Jonathan C P Reum

Full Text Available 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

Impacts of ocean acidification on marine seafood.

Science.gov (United States)

Branch, Trevor A; DeJoseph, Bonnie M; Ray, Liza J; Wagner, Cherie A

2013-03-01

Ocean acidification is a series of chemical reactions due to increased CO(2) emissions. The resulting lower pH impairs the senses of reef fishes and reduces their survival, and might similarly impact commercially targeted fishes that produce most of the seafood eaten by humans. Shelled molluscs will also be negatively affected, whereas cephalopods and crustaceans will remain largely unscathed. Habitat changes will reduce seafood production from coral reefs, but increase production from seagrass and seaweed. Overall effects of ocean acidification on primary productivity and, hence, on food webs will result in hard-to-predict winners and losers. Although adaptation, parental effects, and evolution can mitigate some effects of ocean acidification, future seafood platters will look rather different unless CO(2) emissions are curbed. Copyright © 2012 Elsevier Ltd. All rights reserved.

Communicating Ocean Acidification

Science.gov (United States)

Pope, Aaron; Selna, Elizabeth

2013-01-01

Participation in a study circle through the National Network of Ocean and Climate Change Interpretation (NNOCCI) project enabled staff at the California Academy of Sciences to effectively engage visitors on climate change and ocean acidification topics. Strategic framing tactics were used as staff revised the scripted Coral Reef Dive program,…

Water on a Hydrophobic surface

Science.gov (United States)

Scruggs, Ryan; Zhu, Mengjue; Poynor, Adele

2012-02-01

Hydrophobicity, meaning literally fear of water, is exhibited on the surfaces of non-stick cooking pans and water resistant clothing, on the leaves of the lotus plan, or even during the protein folding process in our bodies. Hydrophobicity is directly measured by determining a contact angle between water and an objects surface. Associated with a hydrophobic surface is the depletion layer, a low density region approximately 0.2 nm thick. We study this region by comparing data found in lab using surface plasmon resonance techniques to theoretical calculations. Experiments use gold slides coated in ODT and Mercapto solutions to model both hydrophobic and hydrophilic surfaces respectively.

Predicting the Response of Molluscs to the Impact of Ocean Acidification

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John M. Wright

2013-04-01

Full Text Available 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.

Predicting the Response of Molluscs to the Impact of Ocean Acidification

Science.gov (United States)

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

An integrated approach to planning and rehabilitation for the future: proceedings of the 2. mining and the environment conference - Sudbury '99: volume two: ecosystems: health evaluation and restoration technologies, ground and surface water remediation

Energy Technology Data Exchange (ETDEWEB)

Goldsack, D. [ed.] [Laurentian Univ., Sudbury, ON (Canada). Centre in Mining and Mining Environment Research; Belzile, P. [ed.] [Laurentian Univ., Sudbury, ON (Canada). Dept.of Chemistry and Biochemistry; Yearwood, P. [ed.] [Inco Ltd., Copper Cliff, ON (Canada). Environmental Control and Occupational Health; Hall, G. [ed.] [Falconbridge Ltd., Falconbridge, ON (Canada). Technology Centre

1999-07-01

Volume two of the symposium featured 27 papers under the general headings of ecosystems - health evaluation and restoration technologies; and ground and surface water remediation. Five papers are abstracted separately on the use of catchment liming for the improvement of drainage water quality from smelter-impacted lands, the effects of emission reductions from the smelters in Sudbury on recovery of lakes within the metal deposition zone, the effects of regional reductions in sulphur deposition on the recovery of biodiversity in lakes, the influence of drought-induced acidification on biotic recovery and the use of catchment liming for the improvement of drainage water quality from smelter-impacted lands.

Studying ocean acidification in the Arctic Ocean

Science.gov (United States)

Robbins, Lisa

2012-01-01

The U.S. Geological Survey (USGS) partnership with the U.S. Coast Guard Ice Breaker Healey and its United Nations Convention Law of the Sea (UNCLOS) cruises has produced new synoptic data from samples collected in the Arctic Ocean and insights into the patterns and extent of ocean acidification. This framework of foundational geochemical information will help inform our understanding of potential risks to Arctic resources due to ocean acidification.

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

Science.gov (United States)

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?

Calcium carbonate production response to future ocean warming and acidification

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A. J. Pinsonneault

2012-06-01

Full Text Available Anthropogenic carbon dioxide (CO₂ emissions are acidifying the ocean, affecting calcification rates in pelagic organisms, and thereby modifying the oceanic carbon and alkalinity cycles. However, the responses of pelagic calcifying organisms to acidification vary widely between species, contributing uncertainty to predictions of atmospheric CO₂ and the resulting climate change. At the same time, ocean warming caused by rising CO₂ is expected to drive increased growth rates of all pelagic organisms, including calcifiers. It thus remains unclear whether anthropogenic CO₂ emissions will ultimately increase or decrease pelagic calcification rates. Here, we assess the importance of this uncertainty by introducing a dependence of calcium carbonate (CaCO₃ production on calcite saturation state (Ω_CaCO3 in an intermediate complexity coupled carbon-climate model. In a series of model simulations, we examine the impact of several variants of this dependence on global ocean carbon cycling between 1800 and 3500 under two different CO₂ emissions scenarios. Introducing a calcification-saturation state dependence has a significant effect on the vertical and surface horizontal alkalinity gradients, as well as on the removal of alkalinity from the ocean through CaCO₃ burial. These changes result in an additional oceanic uptake of carbon when calcification depends on Ω_CaCO3 (of up to 270 Pg C, compared to the case where calcification does not depend on acidification. In turn, this response causes a reduction of global surface air temperature of up to 0.4 °C in year 3500. Different versions of the model produced varying results, and narrowing this range of uncertainty will require better understanding of both temperature and acidification effects on pelagic calcifiers. Nevertheless, our results suggest that alkalinity observations can be used

Linking water and carbon cycles through salinity observed from space

Science.gov (United States)

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.

Ocean acidification: One potential driver of phosphorus eutrophication.

Science.gov (United States)

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 (pocean acidification was one potential facilitator of phosphorus eutrophication in oxic conditions. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effects of ocean acidification on juvenile red king crab (Paralithodes camtschaticus and Tanner crab (Chionoecetes bairdi growth, condition, calcification, and survival.

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William Christopher Long

Full Text Available 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.

Seasonal variation in aragonite saturation in surface waters of Puget Sound – a pilot study

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Gregory Pelletier

2018-01-01

Full Text Available A pilot study of sampling, using monthly marine flights over spatially distributed stations, was conducted with the aim to characterize the carbonate system in Puget Sound over a full year-long period. Surface waters of Puget Sound were found to be under-saturated with respect to aragonite during October–March, and super-saturated during April–September. Highest pCO2 and lowest pH occurred during the corrosive October–March period. Lowest pCO2 and highest pH occurred during the super-saturated April–September period. The monthly variations in pCO2 , pH, and aragonite saturation state closely followed the variations in monthly average chlorophyll a. Super-saturated conditions during April–September are likely strongly influenced by photosynthetic uptake of CO2 during the phytoplankton growing season. The relationship between phytoplankton production, the carbonate system, and aragonite saturation state suggests that long-term trends in eutrophication processes may contribute to trends in ocean acidification in Puget Sound

Economic Vulnerability Assessment of U.S. Fishery Revenues to Ocean Acidification

Science.gov (United States)

Cooley, S. R.; Doney, S. C.

2008-12-01

Ocean acidification, a predictable consequence of rising anthropogenic CO2 emissions, is poised to change marine ecosystems profoundly by decreasing average ocean pH and the carbonate mineral saturation state worldwide. These conditions slow or reverse marine plant and animal calcium carbonate shell growth, thereby harming economically valuable species. In 2006, shellfish and crustaceans provided 50% of the 4 billion U.S. domestic commercial harvest value; value added to commercial fishery products contributed 35 billion to the gross national product that year. Laboratory studies have shown that ocean acidification decreases shellfish calcification; ocean acidification--driven declines in commercial shellfish and crustacean harvests between now and 2060 could decrease nationwide time-integrated primary commercial revenues by 860 million to 14 billion (net present value, 2006 dollars), depending on CO2 emissions, discount rates, biological responses, and fishery structure. This estimate excludes losses from coral reef damage and possible fishery collapses if ocean acidification pushes ecosystems past ecological tipping points. Expanding job losses and indirect economic costs will follow harvest decreases as ocean acidification broadly damages marine habitats and alters marine resource availability. Losses will harm many regions already possessing little economic resilience. The only true solution to ocean acidification is reducing atmospheric CO2 emissions, but implementing regional adaptive responses now from an ecosystem-wide, fisheries perspective will help better preserve sustainable ecosystem function and economic yields. Comprehensive management strategies must include monitoring critical fisheries, explicitly accounting for ocean acidification in management models, reducing fishing pressure and environmental stresses, and supporting regional economies most sensitive to acidification's impacts.

Quantifying Organic Matter in Surface Waters of the United States and Delivery to the Coastal Zone

Science.gov (United States)

Boyer, E. W.; Alexander, R. B.; Smith, R. A.; Shih, J.

2012-12-01

. 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.

Towards improved socio-economic assessments of ocean acidification's impacts.

Science.gov (United States)

Hilmi, Nathalie; Allemand, Denis; Dupont, Sam; Safa, Alain; Haraldsson, Gunnar; Nunes, Paulo A L D; Moore, Chris; Hattam, Caroline; Reynaud, Stéphanie; Hall-Spencer, Jason M; Fine, Maoz; Turley, Carol; Jeffree, Ross; Orr, James; Munday, Philip L; Cooley, Sarah R

2013-01-01

Ocean acidification is increasingly recognized as a component of global change that could have a wide range of impacts on marine organisms, the ecosystems they live in, and the goods and services they provide humankind. Assessment of these potential socio-economic impacts requires integrated efforts between biologists, chemists, oceanographers, economists and social scientists. But because ocean acidification is a new research area, significant knowledge gaps are preventing economists from estimating its welfare impacts. For instance, economic data on the impact of ocean acidification on significant markets such as fisheries, aquaculture and tourism are very limited (if not non-existent), and non-market valuation studies on this topic are not yet available. Our paper summarizes the current understanding of future OA impacts and sets out what further information is required for economists to assess socio-economic impacts of ocean acidification. Our aim is to provide clear directions for multidisciplinary collaborative research.

Acidification research: evaluation and policy applications; a United Kingdom policy response

International Nuclear Information System (INIS)

Derwent, R.G.; Wilson, R.B.

1992-01-01

The United Kingdom environmental research into the mechanisms of the atmospheric transport and deposition of acidity, to understand the impacts of that acidity on soils, surface waters, forests, crops and the built environment and the consequences for fishery status, freshwater and soil ecosystems. The Critical Loads Approach opens the possibility of more subtle and sensitive ways of tackling the problems of environmental acidification on the European scale. The United Kingdom is contributing vigorously to the Critical Loads Approach through the mapping exercises, the environmental studies that underpin them and the understanding of the driving deposition mechanisms which lead both to pollutant removal and ecosystem contamination. Future progress with the UN ECE Convention on the Long Range Transport of Air Pollution and the revision of the NO x , SO 2 and VOC protocols will rest in very large measure on the shared confidence within Europe in the knowledge of the underpinning environmental science. The Critical Loads Approach should provide an important policy focus within the international scientific community to set environmentally-based targets for future co-ordinated emission control programmes

Effects of near-future ocean acidification, fishing, and marine protection on a temperate coastal ecosystem.

Science.gov (United States)

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.

Experimental ocean acidification alters the allocation of metabolic energy.

Science.gov (United States)

Pan, T-C Francis; Applebaum, Scott L; Manahan, Donal T

2015-04-14

Energy is required to maintain physiological homeostasis in response to environmental change. Although responses to environmental stressors frequently are assumed to involve high metabolic costs, the biochemical bases of actual energy demands are rarely quantified. We studied the impact of a near-future scenario of ocean acidification [800 µatm partial pressure of CO2 (pCO2)] during the development and growth of an important model organism in developmental and environmental biology, the sea urchin Strongylocentrotus purpuratus. Size, metabolic rate, biochemical content, and gene expression were not different in larvae growing under control and seawater acidification treatments. Measurements limited to those levels of biological analysis did not reveal the biochemical mechanisms of response to ocean acidification that occurred at the cellular level. In vivo rates of protein synthesis and ion transport increased ∼50% under acidification. Importantly, the in vivo physiological increases in ion transport were not predicted from total enzyme activity or gene expression. Under acidification, the increased rates of protein synthesis and ion transport that were sustained in growing larvae collectively accounted for the majority of available ATP (84%). In contrast, embryos and prefeeding and unfed larvae in control treatments allocated on average only 40% of ATP to these same two processes. Understanding the biochemical strategies for accommodating increases in metabolic energy demand and their biological limitations can serve as a quantitative basis for assessing sublethal effects of global change. Variation in the ability to allocate ATP differentially among essential functions may be a key basis of resilience to ocean acidification and other compounding environmental stressors.

Acidification of a white spruce ecosystem in eastern Cape Breton Island

International Nuclear Information System (INIS)

Bouman, O.T.

2005-01-01

A study was conducted in 2003 at an ecosystem monitoring plot near Sydney, Nova Scotia, in a mature white spruce stand on a Shulie soil. The objective was to examine how spruce forests filter atmospheric sulfur dioxide and become destabilized by the resulting soil acidification. The acid rain problem at the level of input, top soil, sub soil and run off was assessed following results from 4 monitoring stations equipped for bulk sampling of throughfall water and two lysimeters for soil water extraction at a depth of 15 cm and 45 cm, respectively. Rainwater was collected in 2 open areas outside the forest along with samples from a stream draining the forest and surrounding wetland. Water samples were collected 8 times between April 2003 and November 2004. Results show that the problem of acid rain is present in eastern Cape Breton Island. Canopy passage was found to lower the average rainwater pH from 4.7 to 4.2 with a related increase of sulfate from 2.2 ppm to 8.3 ppm. Top soil solution pH was 3.9 increasing to 4.5 in the sub soil. Aluminum was found to increase significantly in the soil solution when pH dropped below 4.2. This demonstrated that soil acidification due to acid rain frees the aluminum in the top soil. However, the concentration of metal was reduced at lower soil depth due to base cation exchange. High sodium concentrations in rainwater and throughfall were closely associated with sulfate values, indicating high inputs of saline oceanic spray with the potential to cause a salt effect in the top soil chemistry. Most water samples had very low nitrate concentrations. The water chemistry in the stream fluctuated with the pH, often dropping below 5 when sulfate contents increased during high run off events

IAEA To Launch Centre On Ocean Acidification

International Nuclear Information System (INIS)

2012-01-01

Full text: The International Atomic Energy Agency (IAEA) is to launch a new centre this summer to address the growing problem of ocean acidification. Operated by the Agency's Monaco Environmental Laboratories, the Ocean Acidification International Coordination Centre will serve the scientific community - as well as policymakers, universities, media and the general public - by facilitating, promoting and communicating global actions on ocean acidification. Growing amounts of carbon dioxide in the Earth's atmosphere are being absorbed in the planet's oceans which increases their acidity. According to the experts, ocean acidification may render most regions of the ocean inhospitable to coral reefs by 2050 if atmospheric carbon dioxide levels continue to increase. This could lead to substantial changes in commercial fish stocks, threatening food security for millions of people as well as the multi-billion dollar fishing industry. International scientists have been studying the effect and possible responses, and the new centre will help coordinate their efforts. ''During the past five years, numerous multinational and national research projects on ocean acidification have emerged and significant research advances have been made,'' said Daud bin Mohamad, IAEA Deputy Director General for Nuclear Sciences and Applications. ''The time is now ripe to provide international coordination to gain the greatest value from national efforts and research investments.'' The centre will be supported by several IAEA Member States and through the Peaceful Uses Initiative, and it will be overseen by an Advisory Board consisting of leading institutions, including the U.N. Intergovernmental Oceanographic Commission, the U.S. National Oceanic and Atmospheric Administration, the U.N. Food and Agriculture Organization, the Fondation Prince Albert II de Monaco, the OA-Reference User Group, as well as leading scientists and economists in the field. The new centre will focus on international

Acidification of forest soil in Russia: From 1893 to present

Science.gov (United States)

Lapenis, A.G.; Lawrence, G.B.; Andreev, A.A.; Bobrov, A.A.; Torn, M.S.; Harden, J.W.

2004-01-01

It is commonly believed that fine-textured soils developed on carbonate parent material are well buffered from possible acidification. There are no data, however, that document resistance of such soils to acidic deposition exposure on a timescale longer than 30-40 years. In this paper, we report on directly testing the long-term buffering capacity of nineteenth century forest soils developed on calcareous silt loam. In a chemical analysis comparing archived soils with modern soils collected from the same locations ???100 years later, we found varying degrees of forest-soil acidification in the taiga and forest steppe regions. Land-use history, increases in precipitation, and acidic deposition were contributing factors in acidification. The acidification of forest soil was documented through decreases in soil pH and changes in concentrations of exchangeable calcium and aluminum, which corresponded with changes in communities of soil microfauna. Although acidification was found at all three analyzed locations, the trends in soil chemistry were most pronounced where the highest loading of acidic deposition had taken place. Copyright 2004 by the American Geophysical Union.

Odor tracking in sharks is reduced under future ocean acidification conditions.

Science.gov (United States)

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.

Climate change and ocean acidification-interactions with aquatic toxicology.

Science.gov (United States)

Nikinmaa, Mikko

2013-01-15

The possibilities for interactions between toxicants and ocean acidification are reviewed from two angles. First, it is considered how toxicant responses may affect ocean acidification by influencing the carbon dioxide balance. Second, it is introduced, how the possible changes in environmental conditions (temperature, pH and oxygenation), expected to be associated with climate change and ocean acidification, may interact with the toxicant responses of organisms, especially fish. One significant weakness in available data is that toxicological research has seldom been connected with ecological and physiological/biochemical research evaluating the responses of organisms to temperature, pH or oxygenation changes occurring in the natural environment. As a result, although there are significant potential interactions between toxicants and natural environmental responses pertaining to climate change and ocean acidification, it is very poorly known if such interactions actually occur, and can be behind the observed disturbances in the function and distribution of organisms in our seas. Copyright © 2012 Elsevier B.V. All rights reserved.

Ocean acidification in the Mediterranean Sea: pelagic mesocosm experiments. A synthesis

OpenAIRE

Maugendre , L.; Guieu , C.; Gattuso , J.-P.; Gazeau , F.

2017-01-01

International audience; Planet Earth has entered a new geological era, the Anthropocene, in which geologically significant conditions and processes are profoundly altered by human activities (Waters et al., 2016). Among many impacts, human activities have released excessive amounts of carbon dioxide (CO2) in the atmosphere leading to warming and ocean acidification: a decrease in pH and CO32- concentration and an increase in CO2 and HCO3- concentrations (Gattuso and Hansson, 2011). On average...

Reviews and syntheses: Ice acidification, the effects of ocean acidification on sea ice microbial communities

Science.gov (United States)

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 (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

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

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

Science.gov (United States)

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.

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

Directory of Open Access Journals (Sweden)

Joy N Smith

Full Text Available 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.

The exposure of the Great Barrier Reef to ocean acidification

KAUST Repository

Mongin, Mathieu; Baird, Mark E.; Tilbrook, Bronte; Matear, Richard J.; Lenton, Andrew; Herzfeld, Mike; Wild-Allen, Karen; Skerratt, Jenny; Margvelashvili, Nugzar; Robson, Barbara J.; Duarte, Carlos M.; Gustafsson, Malin S. M.; Ralph, Peter J.; Steven, Andrew D. L.

2016-01-01

The Great Barrier Reef (GBR) is founded on reef-building corals. Corals build their exoskeleton with aragonite, but ocean acidification is lowering the aragonite saturation state of seawater (Ωa). The downscaling of ocean acidification projections

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

Science.gov (United States)

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 (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.

A quantitative assay for lysosomal acidification rates in human osteoclasts

DEFF Research Database (Denmark)

Jensen, Vicki Kaiser; Nosjean, Olivier; Dziegiel, Morten Hanefeld

2011-01-01

The osteoclast initiates resorption by creating a resorption lacuna. The ruffled border surrounding the lacunae arises from exocytosis of lysosomes. To dissolve the inorganic phase of the bone, the vacuolar adenosine triphosphatase, located in the ruffled border, pumps protons into the resorption...... assay with respect to lysosomal acidification and assess whether it is a reliable test of a compound's ability to inhibit acidification. Investigated were the expression levels of the lysosomal acidification machinery, the activation of the assay by adenosine triphosphate, H(+) and Cl(-) dependency...

Differential Effects of Ocean Acidification on Coral Calcification: Insights from Geochemistry.

Science.gov (United States)

Holcomb, M.; Decarlo, T. M.; Venn, A.; Tambutte, E.; Gaetani, G. A.; Tambutte, S.; Allemand, D.; McCulloch, M. T.

2014-12-01

Although ocean acidification is expected to negatively impact calcifying animals due to the formation of CaCO3 becoming less favorable, experimental evidence is mixed. Corals have received considerable attention in this regard; laboratory culture experiments show there to be a wide array of calcification responses to acidification. Here we will show how relationships for the incorporation of various trace elements and boron isotopes into synthetic aragonite can be used to reconstruct carbonate chemistry at the site of calcification. In turn the chemistry at the site of calcification can be determined under different ocean acidification scenarios and differences in the chemistry at the site of calcification linked to different calcification responses to acidification. Importantly we will show that the pH of the calcifying fluid alone is insufficient to estimate calcification responses, thus a multi-proxy approach using multiple trace elements and isotopes is required to understand how the site of calcification is affected by ocean acidification.

Our Changing Oceans: All about Ocean Acidification

International Nuclear Information System (INIS)

Rickwood, Peter

2013-01-01

The consequences of ocean acidification are global in scale. More research into ocean acidification and its consequences is needed. It is already known, for example, that there are regional differences in the vulnerability of fisheries to acidification. The combination of other factors, such as global warming, the destruction of habitats, overfishing and pollution, need to be taken into account when developing strategies to increase the marine environment’s resilience. Among steps that can be taken to reduce the impact is better protection of marine coastal ecosystems, such as mangrove swamps and seagrass meadows, which will help protect fisheries. This recommendation was one of the conclusions of a three-day workshop attended by economists and scientists and organized by the IAEA and the Centre Scientifique de Monaco in November 2012. In their recommendations the workshop also stressed that the impact of increasing ocean acidity must be taken into account in the management of fisheries, particularly where seafood is a main dietary source

Ethanol Induced Urine Acidification is Related with Early Acetaldehyde Concentration

Directory of Open Access Journals (Sweden)

Soon Kil Kwon

2014-06-01

Conclusion: In conclusion, urine acidification after ethanol ingestion is related with serum acetaldehyde concentration. Early elevation of acetaldhyde could induce urine acidification, but the urine pH was elevated after a few hours, that might make prolonged acidemia.

Turf algal epiphytes metabolically induce local pH increase, with implications for underlying coralline algae under ocean acidification

DEFF Research Database (Denmark)

Short, J.A.; Pedersen, Ole; Kendrick, G.A.

2015-01-01

The presence of epiphytic turf algae may modify the effects of ocean acidification on coralline algal calcification rates by altering seawater chemistry within the diffusive boundary layer (DBL) above coralline algal crusts. We used microelectrodes to measure the effects of turf algal epiphytes...... on seawater pH and the partial pressure of oxygen (pO2) within the DBL at the surface of Hydrolithoideae coralline algal crusts under ambient (36 Pa) CO2 and an ocean acidification scenario with elevated CO2 (200 Pa). Turf algae significantly increased the mean diel amplitude of pH and pO2, and this effect...... was more pronounced under elevated CO2. We suggest that increases in seawater CO2 under ocean acidification conditions may drive an increase in the abundance of epiphytic turf algae, consequently modifying the chemistry within the DBL. Thus, the effect of epiphytic turf algae on microscale pH is striking...

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

Science.gov (United States)

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.

Combined impact of ocean acidification and corrosive waters in a river-influenced coastal upwelling area off Central Chile

Science.gov (United States)

Vargas, C.; De La Hoz, M.; San Martin, V.; Contreras, P.; Navarro, J. M.; Lagos, N. A.; Lardies, M.; Manríquez, P. H.; Torres, R.

2012-12-01

Elevated CO2 in the atmosphere promotes a cascade of physical and chemical changes affecting all levels of biological organization, and the evidence from local to global scales has shown that such anthropogenic climate change has triggered significant responses in the Earth's biota. The increased concentration of CO2 is likely to cause a corresponding increase in ocean acidification (OA). In addition, economically valuable shellfish species predominantly inhabit coastal regions both in natural stocks and/or in managed stocks and farming areas. Many coastal ecosystems may experience seawater pCO2 levels significantly higher than expected from equilibrium with the atmosphere, which in this case are strongly linked to biological processes and/or the impact of two important processes; river plumes and coastal upwelling events, which indeed interplay in a very dynamic way on continental shelves, resulting in both source or sink of CO2 to the atmosphere. Coastal ecosystems receive persistent acid inputs as a result of freshwater discharges from river basins into the coastal domain. In this context, since shellfish resources and shellfish aquaculture activities predominantly occur in nearshore areas, it is expected that shellfish species inhabiting river-influenced benthic ecosystems will be exposed persistently to acidic conditions that are suboptimal for its development. In a wider ecological context, little is also known about the potential impacts of acid waters on the performance of larvae and juveniles of almost all the marine species inhabiting this benthic ecosystem in Eastern Southern Pacific Ocean. We present here the main results of a research study aimed to investigate the environmental conditions to which economically valuable calcifiers shellfish species are exposed in a river-influenced continental shelf off Central Chile. By using isotopic measurements in the dissolved inorganic carbon (DIC) pool (d13C-DIC) we showed the effect of the remineralization of

A Dynamic Economic Analysis of Nitrogen-Induced Soil Acidification in China

OpenAIRE

Yang, Ziyan

2015-01-01

This paper studies the environmental value of nitrogen fertilizer in a rapeseed-rice double-crop system in China to address the issue of nitrogen-induced soil acidification in China’s farmland. Previous literature always regarded the acid rain as the most important contributor to soil acidification. Thus, previous literature seldom linked soil quality with nitrogen leaching but studied acidification as a side product of air pollution. However, the latest scientific evidences show that China’s...

Natural ocean acidification at Papagayo upwelling system (north Pacific Costa Rica): implications for reef development

Science.gov (United States)

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.

Millennial-scale ocean acidification and late Quaternary

Energy Technology Data Exchange (ETDEWEB)

Riding, Dr Robert E [University of Tennessee (UT); Liang, Liyuan [ORNL; Braga, Dr Juan Carlos [Universidad de Granada, Departamento de Estratigrafıa y Paleontologıa, Granada, Spain

2014-01-01

Ocean acidification by atmospheric carbon dioxide has increased almost continuously since the last glacial maximum (LGM), 21 000 years ago. It is expected to impair tropical reef development, but effects on reefs at the present day and in the recent past have proved difficult to evaluate. We present evidence that acidification has already significantly reduced the formation of calcified bacterial crusts in tropical reefs. Unlike major reef builders such as coralline algae and corals that more closely control their calcification, bacterial calcification is very sensitive to ambient changes in carbonate chemistry. Bacterial crusts in reef cavities have declined in thickness over the past 14 000 years with largest reduction occurring 12 000 10 000 years ago. We interpret this as an early effect of deglacial ocean acidification on reef calcification and infer that similar crusts were likely to have been thicker when seawater carbonate saturation was increased during earlier glacial intervals, and thinner during interglacials. These changes in crust thickness could have substantially affected reef development over glacial cycles, as rigid crusts significantly strengthen framework and their reduction would have increased the susceptibility of reefs to biological and physical erosion. Bacterial crust decline reveals previously unrecognized millennial-scale acidification effects on tropical reefs. This directs attention to the role of crusts in reef formation and the ability of bioinduced calcification to reflect changes in seawater chemistry. It also provides a long-term context for assessing anticipated anthropogenic effects.

An evaluation and analysis of three dynamic watershed acidification codes (MAGIC, ETD, and ILWAS)

Energy Technology Data Exchange (ETDEWEB)

Jenne, E.A.; Eary, L.E.; Vail, L.W.; Girvin, D.C.; Liebetrau, A.M.; Hibler, L.F.; Miley, T.B.; Monsour, M.J.

1989-01-01

The US Environmental Protection Agency is currently using the dynamic watershed acidification codes MAGIC, ILWAS, and ETD to assess the potential future impact of the acidic deposition on surface water quality by simulating watershed acid neutralization processes. The reliability of forecasts made with these codes is of considerable concern. The present study evaluates the process formulations (i.e., conceptual and numerical representation of atmospheric, hydrologic geochemical and biogeochemical processes), compares their approaches to calculating acid neutralizing capacity (ANC), and estimates the relative effects (sensitivity) of perturbations in the input data on selected output variables for each code. Input data were drawn from three Adirondack (upstate New York) watersheds: Panther Lake, Clear Pond, and Woods Lake. Code calibration was performed by the developers of the codes. Conclusions focus on summarizing the adequacy of process formulations, differences in ANC simulation among codes and recommendations for further research to increase forecast reliability. 87 refs., 11 figs., 77 tabs.

The PIRLA project: paleoecological investigations of recent lake acidification

Energy Technology Data Exchange (ETDEWEB)

Charles, D F; Whitehead, D R

1986-12-19

The PIRLA project is a broadly interdisciplinary paleolimnological investigation of five to fifteen comparable watershed lake systems from each of four low-alkalinity regions in North America that are currently receiving acid deposition. The areas are the Adirondack Mountains (N.Y.), northern New England, northern Great Lakes states, and northern Florida. The primary objective of the study is to provide a detailed reconstruction of the recent acidification histories of a representative suite of lakes from each of the regions. The study will increase our understanding of the timing, rates, and magnitude of acidification (and other chemical changes), and the regional and inter-regional patterns of lake acidification. 3 figs., 2 tabs., 41 refs.

First mesocosm experiments to study the impacts of ocean acidification on plankton communities in the NW Mediterranean Sea (MedSeA project)

Science.gov (United States)

Gazeau, F.; Sallon, A.; Maugendre, L.; Louis, J.; Dellisanti, W.; Gaubert, M.; Lejeune, P.; Gobert, S.; Borges, A. V.; Harlay, J.; Champenois, W.; Alliouane, S.; Taillandier, V.; Louis, F.; Obolensky, G.; Grisoni, J.-M.; Guieu, C.

2017-02-01

There is a growing international interest in studying the effects of ocean acidification on plankton communities that play a major role in the global carbon cycle and in the consumption of atmospheric CO2 via the so-called biological pump. Recently, several mesocosm experiments reported on the effect of ocean acidification on marine plankton communities, although the majority were performed in eutrophic conditions or following nutrient addition. The objective of the present study was to perform two mesocosm experiments in the oligo- to meso-trophic Northwestern Mediterranean Sea during two seasons with contrasting environmental conditions: in summer 2012 in the Bay of Calvi (Corsica, France) and in winter 2013 in the Bay of Villefranche (France). This paper describes the objectives of these experiments, the study sites, the experimental set-up and the environmental and experimental conditions during the two experiments. The 20-day experiment in the Bay of Calvi was undoubtedly representative of summer conditions in the Northwestern Mediterranean Sea with low nutrient and chlorophyll a concentrations, warm waters and high surface solar irradiance. In contrast, the winter experiment, which was reduced to 12 days because of bad weather conditions, failed to reproduce the mesotrophic conditions typical of the wintertime in this area. Indeed, a rapid increase in phytoplankton biomass during the acidification phase led to a strong decrease in nitrate concentrations and an unrealistic N and P co-limitation at this period of the year. An overview of the 11 other papers related to this study and published in this special issue is provided.

77 FR 40860 - Strategic Plan for Federal Research and Monitoring of Ocean Acidification

Science.gov (United States)

2012-07-11

... Plan for Federal Research and Monitoring of Ocean Acidification AGENCY: National Marine Fisheries... Federal Research and Monitoring of Ocean Acidification is being made available for public review and... understanding of the process of ocean acidification, its effects on marine ecosystems, and the steps that could...

Future habitat suitability for coral reef ecosystems under global warming and ocean acidification

OpenAIRE

Couce, Elena M; Ridgwell, Andy J; Hendy, Erica

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...

Seagrass ecophysiological performance under ocean warming and acidification.

Science.gov (United States)

Repolho, Tiago; Duarte, Bernardo; Dionísio, Gisela; Paula, José Ricardo; Lopes, Ana R; Rosa, Inês C; Grilo, Tiago F; Caçador, Isabel; Calado, Ricardo; Rosa, Rui

2017-02-01

Seagrasses play an essential ecological role within coastal habitats and their worldwide population decline has been linked to different types of anthropogenic forces. We investigated, for the first time, the combined effects of future ocean warming and acidification on fundamental biological processes of Zostera noltii, including shoot density, leaf coloration, photophysiology (electron transport rate, ETR; maximum PSII quantum yield, F v /F m ) and photosynthetic pigments. Shoot density was severely affected under warming conditions, with a concomitant increase in the frequency of brownish colored leaves (seagrass die-off). Warming was responsible for a significant decrease in ETR and F v /F m (particularly under control pH conditions), while promoting the highest ETR variability (among experimental treatments). Warming also elicited a significant increase in pheophytin and carotenoid levels, alongside an increase in carotenoid/chlorophyll ratio and De-Epoxidation State (DES). Acidification significantly affected photosynthetic pigments content (antheraxanthin, β-carotene, violaxanthin and zeaxanthin), with a significant decrease being recorded under the warming scenario. No significant interaction between ocean acidification and warming was observed. Our findings suggest that future ocean warming will be a foremost determinant stressor influencing Z. noltii survival and physiological performance. Additionally, acidification conditions to occur in the future will be unable to counteract deleterious effects posed by ocean warming.

Future habitat suitability for coral reef ecosystems under global warming and ocean acidification.

Science.gov (United States)

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

Urbanization in China drives soil acidification of Pinus massoniana forests

Science.gov (United States)

Huang, Juan; Zhang, Wei; Mo, Jiangming; Wang, Shizhong; Liu, Juxiu; Chen, Hao

2015-09-01

Soil acidification instead of alkalization has become a new environmental issue caused by urbanization. However, it remains unclear the characters and main contributors of this acidification. We investigated the effects of an urbanization gradient on soil acidity of Pinus massoniana forests in Pearl River Delta, South China. The soil pH of pine forests at 20-cm depth had significantly positive linear correlations with the distance from the urban core of Guangzhou. Soil pH reduced by 0.44 unit at the 0-10 cm layer in urbanized areas compared to that in non-urbanized areas. Nitrogen deposition, mean annual temperature and mean annual precipitation were key factors influencing soil acidification based on a principal component analysis. Nitrogen deposition showed significant linear relationships with soil pH at the 0-10 cm (for ammonium N (-N), P greatly contributed to a significant soil acidification occurred in the urbanized environment.

Ocean acidification ameliorates harmful effects of warming in primary consumer.

Science.gov (United States)

Pedersen, Sindre Andre; Hanssen, Anja Elise

2018-01-01

Climate change-induced warming and ocean acidification are considered two imminent threats to marine biodiversity and current ecosystem structures. Here, we have for the first time examined an animal's response to a complete life cycle of exposure to co-occurring warming (+3°C) and ocean acidification (+1,600 μatm CO 2 ), using the key subarctic planktonic copepod, Calanus finmarchicus , as a model species. The animals were generally negatively affected by warming, which significantly reduced the females' energy status and reproductive parameters (respectively, 95% and 69%-87% vs. control). Unexpectedly, simultaneous acidification partially offset the negative effect of warming in an antagonistic manner, significantly improving reproductive parameters and hatching success (233%-340% improvement vs. single warming exposure). The results provide proof of concept that ocean acidification may partially offset negative effects caused by warming in some species. Possible explanations and ecological implications for the observed antagonistic effect are discussed.

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

OpenAIRE

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-...

Reconstructing pre-acidification pH for an acidified Scottish loch: A comparison of palaeolimnological and modelling approaches

International Nuclear Information System (INIS)

Battarbee, R.W.; Monteith, D.T.; Juggins, S.; Evans, C.D.; Jenkins, A.; Simpson, G.L.

2005-01-01

We reconstruct the pre-acidification pH of the Round Loch of Glenhead for 1800 AD using three diatom-pH transfer functions and a diatom-cladocera modern analogue technique (MAT), and compare these palaeo-data with hindcast data for the loch using the dynamic catchment acidification model MAGIC. We assess the accuracy of the transfer functions by comparing pH inferences from contemporary sediment and sediment trap diatom samples from the lake with measured pH from the UK Acid Waters Monitoring Network. The results from the transfer functions estimate the pH in 1800 to have been between 5.5. and 5.7, the MAT approach estimates pH at 5.8 and the MAGIC hindcast (for 1850) is pH 6.1. Whilst we have no independent method of assessing which of these values is most accurate, the disagreement between the two approaches indicates that further work is needed to resolve the discrepancies. - Methods of reconstructing pre-acidification pH for an acidified Scottish loch compared

Effect of acidification on an Arctic phytoplankton community from Disko Bay, West Greenland

DEFF Research Database (Denmark)

Thoisen, Christina; Riisgaard, Karen; Lundholm, Nina

2015-01-01

. Our findings show that coastal phytoplankton from Disko Bay is naturally exposed to pH fluctuations exceeding the experimental pH range used in most ocean acidification studies. We emphasize that studies on ocean acidification should include in situ pH before assumptions on the effect of acidification...... on marine organisms can be made. KEY WORDS: Ocean acidification · Coastal · Arctic phytoplankton · Growth rate · pH · CO2 · DIC......ABSTRACT: Long-term measurements (i.e. months) of in situ pH have not previously been reported from the Arctic; this study shows fluctuations between pH 7.5 and 8.3 during the spring bloom 2012 in a coastal area of Disko Bay, West Greenland. The effect of acidification on phytoplankton from...

Protein removal from waste brines generated during ham salting through acidification and centrifugation.

Science.gov (United States)

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®

Controllability of Surface Water Networks

Science.gov (United States)

Riasi, M. Sadegh; Yeghiazarian, Lilit

2017-12-01

To sustainably manage water resources, we must understand how to control complex networked systems. In this paper, we study surface water networks from the perspective of structural controllability, a concept that integrates classical control theory with graph-theoretic formalism. We present structural controllability theory and compute four metrics: full and target controllability, control centrality and control profile (FTCP) that collectively determine the structural boundaries of the system's control space. We use these metrics to answer the following questions: How does the structure of a surface water network affect its controllability? How to efficiently control a preselected subset of the network? Which nodes have the highest control power? What types of topological structures dominate controllability? Finally, we demonstrate the structural controllability theory in the analysis of a wide range of surface water networks, such as tributary, deltaic, and braided river systems.

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

OpenAIRE

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

2016-01-01

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 chemica...

Ecological distribution of pelagic copepods and species relationship to acidification, liming and natural recovery in a boreal area

Directory of Open Access Journals (Sweden)

Svein Birger WÆRVÅGEN

2003-02-01

Full Text Available Distribution and ecology of pelagic copepods were studied in a boreal area strongly affected by acidification in southern Norway. Differential regional composition of bedrock geology and Quaternary deposits combined with liming have produced aquatic sites with contrasting acidification and recovery histories. The omnivorous species Eudiaptomus gracilis showed a striking ability to tolerate both acidification and chemical recovery. The predominantly carnivorous species Heterocope saliens increased numerically during acidification, both because it is tolerant to acidic environments and because fish predation diminished or disappeared altogether. After chemical recovery, H. saliens, having an endogenous egg-bank, most readily produced viable populations with numerical abundance depending upon fish predation pressure. Thermocyclops oithonoides and Cyclops scutifer were negatively affected by strongly acidic environments, whereas Mesocyclops leuckarti tolerated acidic conditions better. All three cyclopoid species increased in abundance after chemical recovery, most probably from small residual populations. The hypolimnetic C. scutifer faced dispersal problems in re-establishing following liming. Deep lakes (>20 m harboured considerable residual populations of C. scutifer which recovered rapidly to pre-acidic conditions. Cyclops abyssorum inhabited the pelagial during early recovery of formerly chronically acidified lakes as a fugitive species, probably due to rapid dispersal capacities. Littoral cyclopoids, such as Acanthocyclops vernalis and Diacyclops nanus, were commonly distributed in the free waters of the most acidic lakes (pH = 4.5-4.8, but disappeared from the pelagial shortly after chemical recovery. The total community of pelagic copepods forms a promising tool to identify historical acidification and trajectories of recovery in the freshwater environment.

Ocean acidification: the other CO2 problem.

Science.gov (United States)

Doney, Scott C; Fabry, Victoria J; Feely, Richard A; Kleypas, Joan A

2009-01-01

Rising atmospheric carbon dioxide (CO2), primarily from human fossil fuel combustion, reduces ocean pH and causes wholesale shifts in seawater carbonate chemistry. The process of ocean acidification is well documented in field data, and the rate will accelerate over this century unless future CO2 emissions are curbed dramatically. Acidification alters seawater chemical speciation and biogeochemical cycles of many elements and compounds. One well-known effect is the lowering of calcium carbonate saturation states, which impacts shell-forming marine organisms from plankton to benthic molluscs, echinoderms, and corals. Many calcifying species exhibit reduced calcification and growth rates in laboratory experiments under high-CO2 conditions. Ocean acidification also causes an increase in carbon fixation rates in some photosynthetic organisms (both calcifying and noncalcifying). The potential for marine organisms to adapt to increasing CO2 and broader implications for ocean ecosystems are not well known; both are high priorities for future research. Although ocean pH has varied in the geological past, paleo-events may be only imperfect analogs to current conditions.

INTERACTIONS BETWEEN OCEAN ACIDIFICATION AND WARMING ON THE MORTALITY AND DISSOLUTION OF CORALLINE ALGAE(1).

Science.gov (United States)

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 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.

Investigating Undergraduate Science Students' Conceptions and Misconceptions of Ocean Acidification

Science.gov (United States)

Danielson, Kathryn I.; Tanner, Kimberly D.

2015-01-01

Scientific research exploring ocean acidification has grown significantly in past decades. However, little science education research has investigated the extent to which undergraduate science students understand this topic. Of all undergraduate students, one might predict science students to be best able to understand ocean acidification. What…

Groundwater–Surface Water Exchange

DEFF Research Database (Denmark)

Karan, Sachin

The exchange of groundwater-surface water has been invetigated in the western part of Denmark. Holtum AA provides the framework for all the performed investigations. Several methods are used, primarily eld based measurements ombined with numerical models to achieve insight to the governing...... processes of interaction between groundwater and surface water. By using heat as a tracer it has been possible to use temperature directly as calibrationtargets in a groundwater and heat transport model. Thus, it is possible to use heat investigate the change in groundwater discharge in dynamic conditions...... by using simple temperature devices along a stream to delineate the areas of interest in regard to GW{SW exchange. Thus, at several locations in a stream a temperature data logger was placed in the water column and right at the streambed-water interface. By looking at the correlation of streambed...

Responses of pink salmon to CO2-induced aquatic acidification

Science.gov (United States)

Ou, Michelle; Hamilton, Trevor J.; Eom, Junho; Lyall, Emily M.; Gallup, Joshua; Jiang, Amy; Lee, Jason; Close, David A.; Yun, Sang-Seon; Brauner, Colin J.

2015-10-01

Ocean acidification negatively affects many marine species and is predicted to cause widespread changes to marine ecosystems. Similarly, freshwater ecosystems may potentially be affected by climate-change-related acidification; however, this has received far less attention. Freshwater fish represent 40% of all fishes, and salmon, which rear and spawn in freshwater, are of immense ecosystem, economical and cultural importance. In this study, we investigate the impacts of CO2-induced acidification during the development of pink salmon, in freshwater and following early seawater entry. At this critical and sensitive life stage, we show dose-dependent reductions in growth, yolk-to-tissue conversion and maximal O2 uptake capacity; as well as significant alterations in olfactory responses, anti-predator behaviour and anxiety under projected future increases in CO2 levels. These data indicate that future populations of pink salmon may be at risk without mitigation and highlight the need for further studies on the impact of CO2-induced acidification on freshwater systems.

Digestion in sea urchin larvae impaired under ocean acidification

Science.gov (United States)

Stumpp, Meike; Hu, Marian; Casties, Isabel; Saborowski, Reinhard; Bleich, Markus; Melzner, Frank; Dupont, Sam

2013-12-01

Larval stages are considered as the weakest link when a species is exposed to challenging environmental changes. Reduced rates of growth and development in larval stages of calcifying invertebrates in response to ocean acidification might be caused by energetic limitations. So far no information exists on how ocean acidification affects digestive processes in marine larval stages. Here we reveal alkaline (~pH 9.5) conditions in the stomach of sea urchin larvae. Larvae exposed to decreased seawater pH suffer from a drop in gastric pH, which directly translates into decreased digestive efficiencies and triggers compensatory feeding. These results suggest that larval digestion represents a critical process in the context of ocean acidification, which has been overlooked so far.

Ocean acidification in a geoengineering context

Science.gov (United States)

Williamson, Phillip; Turley, Carol

2012-01-01

Fundamental changes to marine chemistry are occurring because of increasing carbon dioxide (CO2) in the atmosphere. Ocean acidity (H+ concentration) and bicarbonate ion concentrations are increasing, whereas carbonate ion concentrations are decreasing. There has already been an average pH decrease of 0.1 in the upper ocean, and continued unconstrained carbon emissions would further reduce average upper ocean pH by approximately 0.3 by 2100. Laboratory experiments, observations and projections indicate that such ocean acidification may have ecological and biogeochemical impacts that last for many thousands of years. The future magnitude of such effects will be very closely linked to atmospheric CO2; they will, therefore, depend on the success of emission reduction, and could also be constrained by geoengineering based on most carbon dioxide removal (CDR) techniques. However, some ocean-based CDR approaches would (if deployed on a climatically significant scale) re-locate acidification from the upper ocean to the seafloor or elsewhere in the ocean interior. If solar radiation management were to be the main policy response to counteract global warming, ocean acidification would continue to be driven by increases in atmospheric CO2, although with additional temperature-related effects on CO2 and CaCO3 solubility and terrestrial carbon sequestration. PMID:22869801

Effects of sulphuric acid and acidifying ammonium deposition on water quality and vegetation of simulated soft water ecosystem

Energy Technology Data Exchange (ETDEWEB)

Schuurkes, J.A.A.R.; Heck, I.C.C; Hesen, P.L.G.M.; Leuven, R.S.E.W.; Roelofs, J.G.M.

1986-11-01

In a greenhouse, seven identical mini-ecosystems, simulating soft water ponds, were exposed to different types of artificial rain water. The effects of rain water containing H/sub 2/SO/sub 4/ and nitrate, and rain water containing ammonium sulphate on water quality and vegetation were studied and compared. Causal relations were established between rain water quality, water chemistry and changes in floristic composition. Ammonium sulphate deposition, particularly, strongly affected water quality and vegetation development. Although ammonium sulphate deposition was only slightly acid, due to nitrification it acted as an important acid source, causing acidification to pH 3.8. Under acidified conditions, ammonium sulphate deposition led to a luxuriant growth of Juncus bulbosus and Agrostis canina. In the mini-ecosystems, H/sub 2/SO/sub 4/ deposition with a pH of 3.5 only decreased the pH of the water to 5.1 within 1 yr, the acidification of water appeared to be coupled with changes in alkalinity, sulphate, Al, Cd, Ca, Mg, K and inorganic-N. It is concluded that in NH/sub 3/-affected regions in The Netherlands, the high atmospheric deposition of ammonium sulphate probably contributes to a large extent in the acidification, eutrophication and floristic changes of oligotrophic soft waters. 10 references.

Effects of sulphuric acid and acidifying ammonium deposition on water quality and vegetation of simulated soft water ecosystems

Energy Technology Data Exchange (ETDEWEB)

Schuurkes, J.A.; Heck, I.C.; Hesen, P.L.; Leuven, R.S.; Roelofs, J.G.

1986-11-01

In a greenhouse, seven identical mini-ecosystems, simulating soft water ponds, were exposed to different types of artificial rain water. The effects of rain water containing H/sub 2/SO/sub 4/ and nitrate, and rain water containing ammonium sulfate on water quality and vegetation were studied and compared. Causal relations were established between rain water quality, water chemistry and changes in floristic composition. Ammonium sulfate deposition, particularly, strongly affected water quality and vegetation development. Although ammonium sulfate deposition was only slightly acid, due to nitrification it acted as an important acid source, causing acidification to pH = 3.8. Under acidified conditions, ammonium sulfate deposition lead to a luxuriant growth of Juncus bulbosus and Agrostis canina. In the mini-ecosystems, H/sub 2/SO/sub 4/ deposition with a pH of 3.5 only decreased the pH of the water to 5.1 within 1 yr. The acidification of water appeared to be coupled with changes in alkalinity, sulfate, Al, Cd, Ca, Mg, K and inorganic-N. It is concluded that in NH/sub 3/-affected regions in The Netherlands, the high atmospheric deposition of ammonium sulfate probably contributes to a large extent in the acidification, eutrophication and floristic changes of oligotrophic soft waters. 10 refs.

Impact of Water Withdrawals from Groundwater and Surface Water on Continental Water Storage Variations

Science.gov (United States)

Doell, Petra; Hoffmann-Dobrev, Heike; Portmann, Felix T.; Siebert, Stefan; Eicker, Annette; Rodell, Matthew; Strassberg, Gil

2011-01-01

Humans have strongly impacted the global water cycle, not only water flows but also water storage. We have performed a first global-scale analysis of the impact of water withdrawals on water storage variations, using the global water resources and use model WaterGAP. This required estimation of fractions of total water withdrawals from groundwater, considering five water use sectors. According to our assessment, the source of 35% of the water withdrawn worldwide (4300 cubic km/yr during 1998-2002) is groundwater. Groundwater contributes 42%, 36% and 27% of water used for irrigation, households and manufacturing, respectively, while we assume that only surface water is used for livestock and for cooling of thermal power plants. Consumptive water use was 1400 cubic km/yr during 1998-2002. It is the sum of the net abstraction of 250 cubic km/yr of groundwater (taking into account evapotranspiration and return flows of withdrawn surface water and groundwater) and the net abstraction of 1150 km3/yr of surface water. Computed net abstractions indicate, for the first time at the global scale, where and when human water withdrawals decrease or increase groundwater or surface water storage. In regions with extensive surface water irrigation, such as Southern China, net abstractions from groundwater are negative, i.e. groundwater is recharged by irrigation. The opposite is true for areas dominated by groundwater irrigation, such as in the High Plains aquifer of the central USA, where net abstraction of surface water is negative because return flow of withdrawn groundwater recharges the surface water compartments. In intensively irrigated areas, the amplitude of seasonal total water storage variations is generally increased due to human water use; however, in some areas, it is decreased. For the High Plains aquifer and the whole Mississippi basin, modeled groundwater and total water storage variations were compared with estimates of groundwater storage variations based on

Reef-scale modeling of coral calcification responses to ocean acidification and sea-level rise

Science.gov (United States)

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

Surface composition and surface properties of water hyacinth ...

African Journals Online (AJOL)

Surface composition and surface properties of water hyacinth ( Eichhornia ... (2/1, v/v) followed by ethanol, using Fourier Transform Infra-red (FT-IR) spectroscopy, ... polar organic solvents and non-polar n-alkane hydrocarbons is discussed.

Intraspecific variations in responses to ocean acidification in two branching coral species.

Science.gov (United States)

Sekizawa, Ayami; Uechi, Hikaru; Iguchi, Akira; Nakamura, Takashi; Kumagai, Naoki H; Suzuki, Atsushi; Sakai, Kazuhiko; Nojiri, Yukihiro

2017-09-15

Ocean acidification is widely recognised to have a negative impact on marine calcifying organisms by reducing calcifications, but controversy remains over whether such organisms could cope with ocean acidification within a range of phenotypic plasticity and/or adapt to future acidifying ocean. We performed a laboratory rearing experiment using clonal fragments of the common branching corals Montipora digitata and Porites cylindrica under control and acidified seawater (lower pH) conditions (approximately 400 and 900μatm pCO 2 , respectively) and evaluated the intraspecific variations in their responses to ocean acidification. Intra- and interspecific variations in calcification and photosynthetic efficiency were evident according to both pCO 2 conditions and colony, indicating that responses to acidification may be individually variable at the colony level. Our results suggest that some corals may cope with ocean acidification within their present genotypic composition by adaptation through phenotypic plasticity, while others may be placed under selective pressures resulting in population alteration. Copyright © 2017 Elsevier Ltd. All rights reserved.

Paradigm Lost: Ocean Acidification Will Overturn the Concept of Larval-Fish Biophysical Dispersal

Directory of Open Access Journals (Sweden)

Jeffrey M. Leis

2018-02-01

Full Text Available Most marine ecologists have in the past 25 years changed from supporting a passive-dispersal paradigm for larval marine fishes to supporting a biophysical-dispersal paradigm wherein the behaviour of larvae plays a central role. Research shows larvae of demersal perciform fishes have considerable swimming and orientation abilities over a major portion of their pelagic larval duration. These abilities depend on sensory function, and some recent research has indicated anthropogenic acidification of the oceans will by the end of the century result in sensory dysfunction. This could strongly alter the ability of fish larvae to orientate in the pelagic environment, to locate suitable settlement habitat, to bet-hedge, and to colonize new locations. This paper evaluates the available publications on the effects of acidification on senses and behaviours relevant to dispersal of fish early life-history stages. A large majority of studies tested CO2 values predicted for the middle to end of the century. Larvae of fourteen families—all but two perciform—were studied. However, half of studies used Damselfishes (Pomacentridae, and except for swimming, most studies used settlement-stage larvae or later stages. In spite of these taxonomic and ontogenetic restrictions, all but two studies on sensory function (chemosensation, hearing, vision, detection of estuarine cues found deleterious effects from acidification. The four studies on lateralization and settlement timing all found deleterious effects from acidification. No clear effect of acidification on swimming ability was found. If fish larvae cannot orientate due to sensory dysfunction, their dispersal will, in effect, conform to the passive dispersal paradigm. Modelling incorporating larval behaviour derived from empirical studies indicates that relative to active larvae, passive larvae will have less self-recruitment, higher median and mean dispersal distances, and lower settlement rates: further, bet

Ocean acidification alters fish populations indirectly through habitat modification

Science.gov (United States)

Nagelkerken, Ivan; Russell, Bayden D.; Gillanders, Bronwyn M.; Connell, Sean D.

2016-01-01

Ocean ecosystems are predicted to lose biodiversity and productivity from increasing ocean acidification. Although laboratory experiments reveal negative effects of acidification on the behaviour and performance of species, more comprehensive predictions have been hampered by a lack of in situ studies that incorporate the complexity of interactions between species and their environment. We studied CO2 vents from both Northern and Southern hemispheres, using such natural laboratories to investigate the effect of ocean acidification on plant-animal associations embedded within all their natural complexity. Although we substantiate simple direct effects of reduced predator-avoidance behaviour by fishes, as observed in laboratory experiments, we here show that this negative effect is naturally dampened when fish reside in shelter-rich habitats. Importantly, elevated CO2 drove strong increases in the abundance of some fish species through major habitat shifts, associated increases in resources such as habitat and prey availability, and reduced predator abundances. The indirect effects of acidification via resource and predator alterations may have far-reaching consequences for population abundances, and its study provides a framework for a more comprehensive understanding of increasing CO2 emissions as a driver of ecological change.

Infiltration of pesticides in surface water into nearby drinking water supply wells

DEFF Research Database (Denmark)

Malaguerra, Flavio; Albrechtsen, Hans-Jørgen; Binning, Philip John

Drinking water wells are often placed near streams because streams often overly permeable sediments and the water table is near the surface in valleys, and so pumping costs are reduced. The lowering of the water table by pumping wells can reverse the natural flow from the groundwater to the stream......, inducing infiltration of surface water to groundwater and consequently to the drinking water well. Many attenuation processes can take place in the riparian zone, mainly due to mixing, biodegradation and sorption. However, if the water travel time from the surface water to the pumping well is too short......, or if the compounds are poorly degradable, contaminants can reach the drinking water well at high concentrations, jeopardizing drinking water quality. Here we developed a reactive transport model to evaluate the risk of contamination of drinking water wells by surface water pollution. The model was validated using...

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

Science.gov (United States)

Bazova, Mariya; Moiseenko, Tatyana

2016-04-01

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»

Impact of ocean acidification and warming on the Mediterranean mussel (Mytilus galloprovincialis

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Frédéric eGazeau

2014-11-01

Full Text Available In order to assess the effects of ocean acidification and warming on the Mediterranean mussel (Mytilus galloprovincialis, specimens were reared in aquarium tanks and exposed to elevated conditions of temperature (+3 °C and acidity (-0.3 pH units for a period of 10 months. The whole system comprised a factorial experimental design with 4 treatments (3 aquaria per treatment: control, lowered pH, elevated temperature and lowered pH/elevated temperature. Mortality was estimated on a weekly basis and every 2 months, various biometrical parameters and physiological processes were measured: somatic and shell growth, metabolic rates and body fluid acid-base parameters. Mussels were highly sensitive to warming, with 100 % mortality observed under elevated temperature at the end of our experiment in October. Mortality rates increased drastically in summer, when water temperature exceeded 25 °C. In contrast, our results suggest that survival of this species will not be affected by a pH decrease of ~0.3 in the Mediterranean Sea. Somatic and shell growth did not appear very sensitive to ocean acidification and warming during most of the experiment, but were reduced, after summer, in the lowered pH treatment. This was consistent with measured shell net dissolution and observed loss of periostracum, as well as uncompensated extracellular acidosis in the lowered pH treatment indicating a progressive insufficiency in acid-base regulation capacity. However, based on the present dataset, we cannot elucidate if these decreases in growth and regulation capacities after summer are a consequence of lower pH levels during that period or a consequence of a combined effect of acidification and warming. To summarize, while ocean acidification will potentially contribute to lower growth rates, especially in summer when mussels are exposed to sub-optimal conditions, ocean warming will likely pose more serious threats to Mediterranean mussels in this region in the coming

U.S. ocean acidification researchers: First national meeting

Science.gov (United States)

Cooley, Sarah R.; Kleypas, Joan; Benway, Heather

2011-09-01

Ocean Carbon and Biogeochemistry Program Ocean Acidification Principal Investigators' Meeting; Woods Hole, Massachusetts, 22-24 March 2011 ; Ocean acidification (OA) is the progressive decrease in seawater pH and change in inorganic carbon chemistry caused by uptake of anthropogenic carbon dioxide (CO2). Marine species respond to OA in multiple ways that could profoundly alter ocean ecosystems and the goods and services they provide to human communities. With major support from the National Oceanic and Atmospheric Administration (NOAA) and the U.S. National Science Foundation (NSF) and additional support from the U.S. Environmental Protection Agency (EPA), the Naval Postgraduate School, and the U.S. Geological Survey (USGS), the Ocean Carbon and Biogeochemistry (OCB) Project Office and Ocean Acidification Subcommittee (http://www.us-ocb.org/about/subcommittees.html) held the first multidisciplinary workshop for U.S. OA researchers at the Woods Hole Oceanographic Institution. The 112 attendees included ecologists, paleoceanographers, instrumentation specialists, chemists, biologists, economists, ocean and ecosystem modelers, and communications specialists.

Waste water treatment in surface mines

Energy Technology Data Exchange (ETDEWEB)

Navasardyants, M A; Esipov, V Z; Ryzhkov, Yu A

1981-01-01

This paper evaluates problems associated with waste water from coal surface mines of the Kemerovougol' association in the Kuzbass. Waste water treatment in the Kuzbass is of major importance as the region is supplied with water from only one river, the Tom river. Water influx to Kemerovougol' surface mines in a year amounts to 136 million m/sup 3/. The water is used during technological processes, for fire fighting, and spraying to prevent dusting; the rest, about 82.1 million m/sup 3/, is discharged into surface waters. Of this amount, 25.1 million m/sup 3/ is heavily polluted water, 46.6 million m3 are polluted but within limits, and 10.4 million m/sup 3/ are characterized as relatively clean. Waste water is polluted with: suspended matters, oils and oil products, nitrates, nitrides and chlorides. Suspended matter content sometimes reaches 4,000 and 5,000 mg/l, and oil product content in water amounts to 2.17 mg/l. Water treatment in surface mines is two-staged: sumps and sedimentation tanks are used. Water with suspended matter content of 50 to 100 mg/l in winter and summer, and 200 to 250 mg/l in spring and autumn is reduced in sumps to 25 to 30 mg/l in summer and winter and to 40 to 50 mg/l in autumn and spring. During the first stage water treatment efficiency ranges from 50 to 80%. During the second stage water is collected in sedimentation tanks. It is noted that so-called secondary pollution is one of the causes of the relatively high level of suspended matter in discharged water. Water discharged from sedimentation tanks carries clay and loam particles from the bottom and walls of water tanks and channels.

Puget Sound ocean acidification model outputs - Modeling the impacts of ocean acidification on ecosystems and populations

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — The NWFSC OA team will model the effects of ocean acidification on regional marine species and ecosystems using food web models, life-cycle models, and bioenvelope...

Coral Reef Ecosystems under Climate Change and Ocean Acidification

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Ove Hoegh-Guldberg

2017-05-01

Full Text Available Coral reefs are found in a wide range of environments, where they provide food and habitat to a large range of organisms as well as providing many other ecological goods and services. Warm-water coral reefs, for example, occupy shallow sunlit, warm, and alkaline waters in order to grow and calcify at the high rates necessary to build and maintain their calcium carbonate structures. At deeper locations (40–150 m, “mesophotic” (low light coral reefs accumulate calcium carbonate at much lower rates (if at all in some cases yet remain important as habitat for a wide range of organisms, including those important for fisheries. Finally, even deeper, down to 2,000 m or more, the so-called “cold-water” coral reefs are found in the dark depths. Despite their importance, coral reefs are facing significant challenges from human activities including pollution, over-harvesting, physical destruction, and climate change. In the latter case, even lower greenhouse gas emission scenarios (such as Representative Concentration Pathway RCP 4.5 are likely drive the elimination of most warm-water coral reefs by 2040–2050. Cold-water corals are also threatened by warming temperatures and ocean acidification although evidence of the direct effect of climate change is less clear. Evidence that coral reefs can adapt at rates which are sufficient for them to keep up with rapid ocean warming and acidification is minimal, especially given that corals are long-lived and hence have slow rates of evolution. Conclusions that coral reefs will migrate to higher latitudes as they warm are equally unfounded, with the observations of tropical species appearing at high latitudes “necessary but not sufficient” evidence that entire coral reef ecosystems are shifting. On the contrary, coral reefs are likely to degrade rapidly over the next 20 years, presenting fundamental challenges for the 500 million people who derive food, income, coastal protection, and a range of

Indices of quality surface water bodies in the planning of water resources

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Rodríguez-Miranda, Juan Pablo

2016-12-01

Full Text Available This paper considers a review of the literature major and significant methods of quality indices of water applied in surface water bodies, used and proposed for assessing the significance of parameters of water quality in the assessment of surface water currents and they are usually used in making decisions for intervention and strategic prevention measures for those responsible for the conservation and preservation of watersheds where these water bodies belong. An exploratory methodology was applied to realize the conceptualization of each water quality index. As a result, it is observed that there are several important methods for determining the water quality index applied in surface water bodies.

Insight into Chemistry on Cloud/Aerosol Water Surfaces.

Science.gov (United States)

Zhong, Jie; Kumar, Manoj; Francisco, Joseph S; Zeng, Xiao Cheng

2018-05-15

Cloud/aerosol water surfaces exert significant influence over atmospheric chemical processes. Atmospheric processes at the water surface are observed to follow mechanisms that are quite different from those in the gas phase. This Account summarizes our recent findings of new reaction pathways on the water surface. We have studied these surface reactions using Born-Oppenheimer molecular dynamics simulations. These studies provide useful information on the reaction time scale, the underlying mechanism of surface reactions, and the dynamic behavior of the product formed on the aqueous surface. According to these studies, the aerosol water surfaces confine the atmospheric species into a specific orientation depending on the hydrophilicity of atmospheric species or the hydrogen-bonding interactions between atmospheric species and interfacial water. As a result, atmospheric species are activated toward a particular reaction on the aerosol water surface. For example, the simplest Criegee intermediate (CH 2 OO) exhibits high reactivity toward the interfacial water and hydrogen sulfide, with the reaction times being a few picoseconds, 2-3 orders of magnitude faster than that in the gas phase. The presence of interfacial water molecules induces proton-transfer-based stepwise pathways for these reactions, which are not possible in the gas phase. The strong hydrophobicity of methyl substituents in larger Criegee intermediates (>C1), such as CH 3 CHOO and (CH 3 ) 2 COO, blocks the formation of the necessary prereaction complexes for the Criegee-water reaction to occur at the water droplet surface, which lowers their proton-transfer ability and hampers the reaction. The aerosol water surface provides a solvent medium for acids (e.g., HNO 3 and HCOOH) to participate in reactions via mechanisms that are different from those in the gas and bulk aqueous phases. For example, the anti-CH 3 CHOO-HNO 3 reaction in the gas phase follows a direct reaction between anti-CH 3 CHOO and HNO 3

Acidification counteracts negative effects of warming on diatom silicification

KAUST Repository

Coello-Camba, Alexandra; Agusti, Susana

2016-01-01

Diatoms are a significant group contributing up to 40 % of annual primary production in the oceans. They have a special siliceous cell wall that, acting as a ballast, plays a key role in the sequestration of global carbon and silica. Diatoms dominate primary production in the Arctic Ocean, where global climate change is causing increases in water temperature and in the partial pressure of CO2 (pCO2). Here we show that as water temperature increases diatoms become stressed, grow to smaller sizes, and decrease their silicification rates. But at higher pCO2, as the pH of seawater decreases, silica incorporation rates are increased. In a future warmer Arctic ocean diatoms may have a competitive advantage under increased ocean acidification, as increased pCO2 counteracts the adverse effects of increasing temperature on silicification and buffers its consequences in the biogeochemical cycles of carbon and silica.

Acidification counteracts negative effects of warming on diatom silicification

KAUST Repository

Coello-Camba, Alexandra

2016-10-24

Diatoms are a significant group contributing up to 40 % of annual primary production in the oceans. They have a special siliceous cell wall that, acting as a ballast, plays a key role in the sequestration of global carbon and silica. Diatoms dominate primary production in the Arctic Ocean, where global climate change is causing increases in water temperature and in the partial pressure of CO2 (pCO2). Here we show that as water temperature increases diatoms become stressed, grow to smaller sizes, and decrease their silicification rates. But at higher pCO2, as the pH of seawater decreases, silica incorporation rates are increased. In a future warmer Arctic ocean diatoms may have a competitive advantage under increased ocean acidification, as increased pCO2 counteracts the adverse effects of increasing temperature on silicification and buffers its consequences in the biogeochemical cycles of carbon and silica.

The Arctic Ocean marine carbon cycle: evaluation of air-sea CO2 exchanges, ocean acidification impacts and potential feedbacks

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N. R. Bates

2009-11-01

Full Text Available At present, although seasonal sea-ice cover mitigates atmosphere-ocean gas exchange, the Arctic Ocean takes up carbon dioxide (CO2 on the order of −66 to −199 Tg C year−1 (1012 g C, contributing 5–14% to the global balance of CO2 sinks and sources. Because of this, the Arctic Ocean has an important influence on the global carbon cycle, with the marine carbon cycle and atmosphere-ocean CO2 exchanges sensitive to Arctic Ocean and global climate change feedbacks. In the near-term, further sea-ice loss and increases in phytoplankton growth rates are expected to increase the uptake of CO2 by Arctic Ocean surface waters, although mitigated somewhat by surface warming in the Arctic. Thus, the capacity of the Arctic Ocean to uptake CO2 is expected to alter in response to environmental changes driven largely by climate. These changes are likely to continue to modify the physics, biogeochemistry, and ecology of the Arctic Ocean in ways that are not yet fully understood. In surface waters, sea-ice melt, river runoff, cooling and uptake of CO2 through air-sea gas exchange combine to decrease the calcium carbonate (CaCO3 mineral saturation states (Ω of seawater while seasonal phytoplankton primary production (PP mitigates this effect. Biological amplification of ocean acidification effects in subsurface waters, due to the remineralization of organic matter, is likely to reduce the ability of many species to produce CaCO3 shells or tests with profound implications for Arctic marine ecosystems

Convergent surface water distributions in U.S. cities

Science.gov (United States)

M.K. Steele; J.B. Heffernan; N. Bettez; J. Cavender-Bares; P.M. Groffman; J.M. Grove; S. Hall; S.E. Hobbie; K. Larson; J.L. Morse; C. Neill; K.C. Nelson; J. O' Neil-Dunne; L. Ogden; D.E. Pataki; C. Polsky; R. Roy Chowdhury

2014-01-01

Earth's surface is rapidly urbanizing, resulting in dramatic changes in the abundance, distribution and character of surface water features in urban landscapes. However, the scope and consequences of surface water redistribution at broad spatial scales are not well understood. We hypothesized that urbanization would lead to convergent surface water abundance and...

Monitoring of Water and Contaminant Migration at the Groundwater-Surface Water Interface

Science.gov (United States)

2008-08-01

seepage is occurring in a freshwater lake environment and to map the lateral extent of any subsurface contamination at the groundwater –surface water ...and Contaminant Migration at the Groundwater -Surface Water Interface August 2008 Report Documentation Page Form ApprovedOMB No. 0704-0188 Public...4. TITLE AND SUBTITLE Monitoring of Water and Contaminant Migration at the Groundwater -Surface Water Interface 5a. CONTRACT NUMBER 5b. GRANT NUMBER

Acidification and warming affect both a calcifying predator and prey, but not their interaction

DEFF Research Database (Denmark)

Landes, Anja; Zimmer, Martin

2012-01-01

Both ocean warming and acidification have been demonstrated to affect the growth, performance and reproductive success of calcifying invertebrates. However, relatively little is known regarding how such environmental change may affect interspecific interactions. We separately treated green crabs...... to environmental change. Acidification negatively affected the closer-muscle length of the crusher chela and correspondingly the claw-strength increment in C. maenas. The effects of warming and/or acidification on L. littorea were less consistent but indicated weaker shells in response to acidification...... Carcinus maenas and periwinkles Littorina littorea under conditions that mimicked either ambient conditions (control) or warming and acidification, both separately and in combination, for 5 mo. After 5 mo, the predators, prey and predator-prey interactions were screened for changes in response...

Ocean Acidification and the End-Permian Mass Extinction: To What Extent does Evidence Support Hypothesis?

OpenAIRE

Kershaw, Stephen; Crasquin, Sylvie; Li, Yue; Collin, Pierre-Yves; Forel, Marie-Béatrice

2012-01-01

Ocean acidification in modern oceans is linked to rapid increase in atmospheric CO2, raising concern about marine diversity, food security and ecosystem services. Proxy evidence for acidification during past crises may help predict future change, but three issues limit confidence of comparisons between modern and ancient ocean acidification, illustrated from the end-Permian extinction, 252 million years ago: (1) problems with evidence for ocean acidification preserved in sedimentary rocks, wh...

Ocean Acidification and the End-Permian Mass Extinction: To What Extent does Evidence Support Hypothesis?

OpenAIRE

Kershaw , Stephen; Crasquin , Sylvie; Li , Yue; Collin , Pierre-Yves; Forel , Marie-Béatrice

2012-01-01

International audience; Ocean acidification in modern oceans is linked to rapid increase in atmospheric CO 2 , raising concern about marine diversity, food security and ecosystem services. Proxy evidence for acidification during past crises may help predict future change, but three issues limit confidence of comparisons between modern and ancient ocean acidification, illustrated from the end-Permian extinction, 252 million years ago: (1) problems with evidence for ocean acidification preserve...

Leaky vessels as a potential source of stromal acidification in tumours

KAUST Repository

Martin, Natasha K.

2010-12-01

Malignant tumours are characterised by higher rates of acid production and a lower extracellular pH than normal tissues. Previous mathematical modelling has indicated that the tumour-derived production of acid leads to a gradient of low pH in the interior of the tumour extending to a normal pH in the peritumoural tissue. This paper uses mathematical modelling to examine the potential of leaky vessels as an additional source of stromal acidification in tumours. We explore whether and to what extent increasing vascular permeability in vessels can lead to the breakdown of the acid gradient from the core of the tumour to the normal tissue, and a progressive acidification of the peritumoural stroma. We compare our mathematical simulations to experimental results found in vivo with a tumour implanted in the mammary fat pad of a mouse in a window chamber construct. We find that leaky vasculature can cause a net acidification of the normal tissue away from the tumour boundary, though not a progressive acidification over time as seen in the experiments. Only through progressively increasing the leakiness can the model qualitatively reproduce the experimental results. Furthermore, the extent of the acidification predicted by the mathematical model is less than as seen in the window chamber, indicating that although vessel leakiness might be acting as a source of acid, it is not the only factor contributing to this phenomenon. Nevertheless, tumour destruction of vasculature could result in enhanced stromal acidification and invasion, hence current therapies aimed at buffering tumour pH should also examine the possibility of preventing vessel disruption.

Reviews and syntheses: Ice acidification, the effects of ocean acidification on sea ice microbial communities

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A. McMinn

2017-09-01

Full Text Available 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

Taking Action Against Ocean Acidification: A Review of Management and Policy Options

Science.gov (United States)

Billé, Raphaël; Kelly, Ryan; Biastoch, Arne; Harrould-Kolieb, Ellycia; Herr, Dorothée; Joos, Fortunat; Kroeker, Kristy; Laffoley, Dan; Oschlies, Andreas; Gattuso, Jean-Pierre

2013-10-01

Ocean acidification has emerged over the last two decades as one of the largest threats to marine organisms and ecosystems. However, most research efforts on ocean acidification have so far neglected management and related policy issues to focus instead on understanding its ecological and biogeochemical implications. This shortfall is addressed here with a systematic, international and critical review of management and policy options. In particular, we investigate the assumption that fighting acidification is mainly, but not only, about reducing CO2 emissions, and explore the leeway that this emerging problem may open in old environmental issues. We review nine types of management responses, initially grouped under four categories: preventing ocean acidification; strengthening ecosystem resilience; adapting human activities; and repairing damages. Connecting and comparing options leads to classifying them, in a qualitative way, according to their potential and feasibility. While reducing CO2 emissions is confirmed as the key action that must be taken against acidification, some of the other options appear to have the potential to buy time, e.g. by relieving the pressure of other stressors, and help marine life face unavoidable acidification. Although the existing legal basis to take action shows few gaps, policy challenges are significant: tackling them will mean succeeding in various areas of environmental management where we failed to a large extent so far.

Taking action against ocean acidification: a review of management and policy options.

Science.gov (United States)

Billé, Raphaël; Kelly, Ryan; Biastoch, Arne; Harrould-Kolieb, Ellycia; Herr, Dorothée; Joos, Fortunat; Kroeker, Kristy; Laffoley, Dan; Oschlies, Andreas; Gattuso, Jean-Pierre

2013-10-01

Ocean acidification has emerged over the last two decades as one of the largest threats to marine organisms and ecosystems. However, most research efforts on ocean acidification have so far neglected management and related policy issues to focus instead on understanding its ecological and biogeochemical implications. This shortfall is addressed here with a systematic, international and critical review of management and policy options. In particular, we investigate the assumption that fighting acidification is mainly, but not only, about reducing CO2 emissions, and explore the leeway that this emerging problem may open in old environmental issues. We review nine types of management responses, initially grouped under four categories: preventing ocean acidification; strengthening ecosystem resilience; adapting human activities; and repairing damages. Connecting and comparing options leads to classifying them, in a qualitative way, according to their potential and feasibility. While reducing CO2 emissions is confirmed as the key action that must be taken against acidification, some of the other options appear to have the potential to buy time, e.g. by relieving the pressure of other stressors, and help marine life face unavoidable acidification. Although the existing legal basis to take action shows few gaps, policy challenges are significant: tackling them will mean succeeding in various areas of environmental management where we failed to a large extent so far.

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

Science.gov (United States)

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 (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.

Decoupling internalization, acidification and phagosomal-endosomal/lysosomal fusion during phagocytosis of InlA coated beads in epithelial cells.

Directory of Open Access Journals (Sweden)

Craig D Blanchette

Full Text Available BACKGROUND: Phagocytosis has been extensively examined in 'professional' phagocytic cells using pH sensitive dyes. However, in many of the previous studies, a separation between the end of internalization, beginning of acidification and completion of phagosomal-endosomal/lysosomal fusion was not clearly established. In addition, very little work has been done to systematically examine phagosomal maturation in 'non-professional' phagocytic cells. Therefore, in this study, we developed a simple method to measure and decouple particle internalization, phagosomal acidification and phagosomal-endosomal/lysosomal fusion in Madin-Darby Canine Kidney (MDCK and Caco-2 epithelial cells. METHODOLOGY/PRINCIPAL FINDINGS: Our method was developed using a pathogen mimetic system consisting of polystyrene beads coated with Internalin A (InlA, a membrane surface protein from Listeria monocytogenes known to trigger receptor-mediated phagocytosis. We were able to independently measure the rates of internalization, phagosomal acidification and phagosomal-endosomal/lysosomal fusion in epithelial cells by combining the InlA-coated beads (InlA-beads with antibody quenching, a pH sensitive dye and an endosomal/lysosomal dye. By performing these independent measurements under identical experimental conditions, we were able to decouple the three processes and establish time scales for each. In a separate set of experiments, we exploited the phagosomal acidification process to demonstrate an additional, real-time method for tracking bead binding, internalization and phagosomal acidification. CONCLUSIONS/SIGNIFICANCE: Using this method, we found that the time scales for internalization, phagosomal acidification and phagosomal-endosomal/lysosomal fusion ranged from 23-32 min, 3-4 min and 74-120 min, respectively, for MDCK and Caco-2 epithelial cells. Both the static and real-time methods developed here are expected to be readily and broadly applicable, as they simply

Food web changes under ocean acidification promote herring larvae survival.

Science.gov (United States)

Sswat, Michael; Stiasny, Martina H; Taucher, Jan; Algueró-Muñiz, Maria; Bach, Lennart T; Jutfelt, Fredrik; Riebesell, Ulf; Clemmesen, Catriona

2018-05-01

Ocean acidification-the decrease in seawater pH due to rising CO 2 concentrations-has been shown to lower survival in early life stages of fish and, as a consequence, the recruitment of populations including commercially important species. To date, ocean-acidification studies with fish larvae have focused on the direct physiological impacts of elevated CO 2 , but largely ignored the potential effects of ocean acidification on food web interactions. In an in situ mesocosm study on Atlantic herring (Clupea harengus) larvae as top predators in a pelagic food web, we account for indirect CO 2 effects on larval survival mediated by changes in food availability. The community was exposed to projected end-of-the-century CO 2 conditions (~760 µatm pCO 2 ) over a period of 113 days. In contrast with laboratory studies that reported a decrease in fish survival, the survival of the herring larvae in situ was significantly enhanced by 19 ± 2%. Analysis of the plankton community dynamics suggested that the herring larvae benefitted from a CO 2 -stimulated increase in primary production. Such indirect effects may counteract the possible direct negative effects of ocean acidification on the survival of fish early life stages. These findings emphasize the need to assess the food web effects of ocean acidification on fish larvae before we can predict even the sign of change in fish recruitment in a high-CO 2 ocean.

Natural ocean acidification at Papagayo upwelling system (north Pacific Costa Rica: implications for reef development

Directory of Open Access Journals (Sweden)

C. Sánchez-Noguera

2018-04-01

Full Text Available 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

Acidic deposition: State of science and technology. Report 10. Watershed and lake processes affecting surface-water acid-base chemistry. Final report

International Nuclear Information System (INIS)

Turner, R.S.; Cook, R.B.; Miegroet, H.V.; Johnson, D.W.; Elwood, J.W.

1990-09-01

The acid-base chemistry of surface waters is governed by the amount and chemistry of deposition and by the biogeochemical reactions that generate acidity or acid neutralizing capacity (ANC) along the hydrologic pathways that water follows through watersheds to streams and lakes. The amount of precipitation and it chemical loading depend on the area's climate and physiography, on it proximity to natural or industrial gaseous or particulate sources, and on local or regional air movements. Vegetation interacts with the atmosphere to enhance both wet and dry deposition of chemicals to a greater or lesser extent, depending on vegetation type. Vegetation naturally acidifies the environment in humid regions through processes of excess base cation uptake and generation of organic acids associated with many biological processes. Natural acid production and atmospheric deposition of acidic materials drive the acidification process. The lake or stream NAC represents a balance between the acidity-and ANC-generating processes that occur along different flow paths in the watershed and the relative importance of each flow path

Ocean acidification changes the structure of an Antarctic coastal protistan community

Science.gov (United States)

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.

The ecology of acidification and recovery: changes in herbivore-algal food web linkages across a stream pH gradient

International Nuclear Information System (INIS)

Ledger, M.E.; Hildrew, A.G.

2005-01-01

We examined the effects of acidification on herbivore-algal food web linkages in headwater streams. We determined the structure and abundance of consumer and benthic algal assemblages, and gauged herbivory, in 10 streams along a pH gradient (mean annual pH 4.6-6.4). Biofilm taxonomic composition changed with pH but total abundance did not vary systematically across the gradient. Mayflies and chironomids dominated under circumneutral conditions but declined with increasing acidity and their consumption of algae was strongly reduced. Contrary to expectations, several putative shredder species consumed algae, maintaining the herbivore-algal linkage where specialist grazers could not persist. These shifts in functioning could render the communities of acidified streams resistant to reinvasion when acidity ameliorates and water chemistry is restored to a pre-acidification condition. This hypothesis is discussed in the light of recent trends in the chemistry and biology of the UK Acid Waters Monitoring Network sites. - Generalist invertebrates maintain algae-herbivore interactions in acid streams

The ecology of acidification and recovery: changes in herbivore-algal food web linkages across a stream pH gradient

Energy Technology Data Exchange (ETDEWEB)

Ledger, M.E. [Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom)]. E-mail: m.e.ledger@bham.ac.uk; Hildrew, A.G. [Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom)

2005-09-15

We examined the effects of acidification on herbivore-algal food web linkages in headwater streams. We determined the structure and abundance of consumer and benthic algal assemblages, and gauged herbivory, in 10 streams along a pH gradient (mean annual pH 4.6-6.4). Biofilm taxonomic composition changed with pH but total abundance did not vary systematically across the gradient. Mayflies and chironomids dominated under circumneutral conditions but declined with increasing acidity and their consumption of algae was strongly reduced. Contrary to expectations, several putative shredder species consumed algae, maintaining the herbivore-algal linkage where specialist grazers could not persist. These shifts in functioning could render the communities of acidified streams resistant to reinvasion when acidity ameliorates and water chemistry is restored to a pre-acidification condition. This hypothesis is discussed in the light of recent trends in the chemistry and biology of the UK Acid Waters Monitoring Network sites. - Generalist invertebrates maintain algae-herbivore interactions in acid streams.

Underground coal mine subsidence impacts on surface water

International Nuclear Information System (INIS)

Stump, D.E. Jr.

1992-01-01

This paper reports that subsidence from underground coal mining alters surface water discharge and availability. The magnitude and areal extent of these impacts are dependent on many factors, including the amount of subsidence, topography, geology, climate, surface water - ground water interactions, and fractures in the overburden. There alterations may have positive and/or negative impacts. One of the most significant surface water impacts occurred in July 1957 near West Pittston, Pennsylvania. Subsidence in the Knox Mine under the Coxton Yards of the Lehigh Valley Railroad allowed part of the discharge in the Susquehanna River to flow into the mine and create a crater 200 feet in diameter and 300 feet deep. Fourteen railroad gondola cars fell into the hole which was eventually filled with rock, sand, and gravel. Other surface water impacts from subsidence may include the loss of water to the ground water system, the gaining of water from the ground water system, the creation of flooded subsidence troughs, the increasing of impoundment storage capacity, the relocation of water sources (springs), and the alteration of surface drainage patterns

Nighttime dissolution in a temperate coastal ocean ecosystem increases under acidification.

Science.gov (United States)

Kwiatkowski, Lester; Gaylord, Brian; Hill, Tessa; Hosfelt, Jessica; Kroeker, Kristy J; Nebuchina, Yana; Ninokawa, Aaron; Russell, Ann D; Rivest, Emily B; Sesboüé, Marine; Caldeira, Ken

2016-03-18

Anthropogenic emissions of carbon dioxide (CO2) are causing ocean acidification, lowering seawater aragonite (CaCO3) saturation state (Ω arag), with potentially substantial impacts on marine ecosystems over the 21(st) Century. Calcifying organisms have exhibited reduced calcification under lower saturation state conditions in aquaria. However, the in situ sensitivity of calcifying ecosystems to future ocean acidification remains unknown. Here we assess the community level sensitivity of calcification to local CO2-induced acidification caused by natural respiration in an unperturbed, biodiverse, temperate intertidal ecosystem. We find that on hourly timescales nighttime community calcification is strongly influenced by Ω arag, with greater net calcium carbonate dissolution under more acidic conditions. Daytime calcification however, is not detectably affected by Ω arag. If the short-term sensitivity of community calcification to Ω arag is representative of the long-term sensitivity to ocean acidification, nighttime dissolution in these intertidal ecosystems could more than double by 2050, with significant ecological and economic consequences.

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

Science.gov (United States)

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.

Oxide/water interfaces: how the surface chemistry modifies interfacial water properties

International Nuclear Information System (INIS)

Gaigeot, Marie-Pierre; Sprik, Michiel; Sulpizi, Marialore

2012-01-01

The organization of water at the interface with silica and alumina oxides is analysed using density functional theory-based molecular dynamics simulation (DFT-MD). The interfacial hydrogen bonding is investigated in detail and related to the chemistry of the oxide surfaces by computing the surface charge density and acidity. We find that water molecules hydrogen-bonded to the surface have different orientations depending on the strength of the hydrogen bonds and use this observation to explain the features in the surface vibrational spectra measured by sum frequency generation spectroscopy. In particular, ‘ice-like’ and ‘liquid-like’ features in these spectra are interpreted as the result of hydrogen bonds of different strengths between surface silanols/aluminols and water. (paper)

Ocean acidification and temperature increase impact mussel shell shape and thickness: problematic for protection?

Science.gov (United States)

Fitzer, Susan C; Vittert, Liberty; Bowman, Adrian; Kamenos, Nicholas A; Phoenix, Vernon R; Cusack, Maggie

2015-11-01

Ocean acidification threatens organisms that produce calcium carbonate shells by potentially generating an under-saturated carbonate environment. Resultant reduced calcification and growth, and subsequent dissolution of exoskeletons, would raise concerns over the ability of the shell to provide protection for the marine organism under ocean acidification and increased temperatures. We examined the impact of combined ocean acidification and temperature increase on shell formation of the economically important edible mussel Mytilus edulis. Shell growth and thickness along with a shell thickness index and shape analysis were determined. The ability of M. edulis to produce a functional protective shell after 9 months of experimental culture under ocean acidification and increasing temperatures (380, 550, 750, 1000 μatm pCO 2, and 750, 1000 μatm pCO 2 + 2°C) was assessed. Mussel shells grown under ocean acidification conditions displayed significant reductions in shell aragonite thickness, shell thickness index, and changes to shell shape (750, 1000 μatm pCO 2) compared to those shells grown under ambient conditions (380 μatm pCO 2). Ocean acidification resulted in rounder, flatter mussel shells with thinner aragonite layers likely to be more vulnerable to fracture under changing environments and predation. The changes in shape presented here could present a compensatory mechanism to enhance protection against predators and changing environments under ocean acidification when mussels are unable to grow thicker shells. Here, we present the first assessment of mussel shell shape to determine implications for functional protection under ocean acidification.

Ocean acidification: The little-known impact of CO2 emissions

International Nuclear Information System (INIS)

Madsen, Michael Amdi

2015-01-01

Ocean acidification, like global warming, is a serious consequence of rising carbon dioxide (CO 2 ) emissions and a growing threat to coastal communities. Scientists and economists alike are calling for ocean acidification mitigation and adaptation plans to be included in any future international climate change agreement, arguing that doing so would make any such agreement stronger and facilitate its implementation. The IAEA uses nuclear techniques to measure ocean acidification and has been providing objective information to scientists, economists, and policymakers to make informed decisions. “Recognizing that billions of people are dependent on a healthy ocean for their wellbeing and economic development is the first step,” said Alexandre Magnan of the Institute for Sustainable Development and International Relations in Paris at an IAEA workshop this year. Acknowledging in the legal text of a climate deal the threats facing the oceans could open the door for coastal communities affected by ocean acidification to benefit from financing available under a climate change agreement, he said. This would enable them to adapt to changing social and economic circumstances, improve understanding of the ecological and biophysical changes expected, and pressure further concrete actions by governments, he added.

Ocean acidification: The little-known impact of CO_2 emissions

International Nuclear Information System (INIS)

Madsen, Michael Amdi

2015-01-01

Ocean acidification, like global warming, is a serious consequence of rising carbon dioxide (CO_2) emissions and a growing threat to coastal communities. Scientists and economists alike are calling for ocean acidification mitigation and adaptation plans to be included in any future international climate change agreement, arguing that doing so would make any such agreement stronger and facilitate its implementation. The IAEA uses nuclear techniques to measure ocean acidification and has been providing objective information to scientists, economists, and policymakers to make informed decisions. “Recognizing that billions of people are dependent on a healthy ocean for their wellbeing and economic development is the first step,” said Alexandre Magnan of the Institute for Sustainable Development and International Relations in Paris at an IAEA workshop this year. Acknowledging in the legal text of a climate deal the threats facing the oceans could open the door for coastal communities affected by ocean acidification to benefit from financing available under a climate change agreement, he said. This would enable them to adapt to changing social and economic circumstances, improve understanding of the ecological and biophysical changes expected, and pressure further concrete actions by governments, he added.

Water's Interfacial Hydrogen Bonding Structure Reveals the Effective Strength of Surface-Water Interactions.

Science.gov (United States)

Shin, Sucheol; Willard, Adam P

2018-06-05

We combine all-atom molecular dynamics simulations with a mean field model of interfacial hydrogen bonding to analyze the effect of surface-water interactions on the structural and energetic properties of the liquid water interface. We show that the molecular structure of water at a weakly interacting ( i.e., hydrophobic) surface is resistant to change unless the strength of surface-water interactions are above a certain threshold. We find that below this threshold water's interfacial structure is homogeneous and insensitive to the details of the disordered surface, however, above this threshold water's interfacial structure is heterogeneous. Despite this heterogeneity, we demonstrate that the equilibrium distribution of molecular orientations can be used to quantify the energetic component of the surface-water interactions that contribute specifically to modifying the interfacial hydrogen bonding network. We identify this specific energetic component as a new measure of hydrophilicity, which we refer to as the intrinsic hydropathy.

Impact of ocean acidification on the early development and escape behavior of marine medaka (Oryzias melastigma).

Science.gov (United States)

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.

The geological record of ocean acidification

NARCIS (Netherlands)

Hönisch, B.; Ridgwell, A.; Schmidt, D.N.; Thomas, E.; Gibbs, S.J.; Sluijs, A.; Zeebe, R.; Kump, L.; Martindale, R.C.; Greene, S.E.; Kiessling, W.; Ries, J.; Zachos, J.C.; Royer, D.L.; Barker, S.; Marchitto Jr., T.M.; Moyer, R.; Pelejero, C.; Ziveri, P.; Foster, G.L.; Williams, B.

2012-01-01

Ocean acidification may have severe consequences for marine ecosystems; however, assessing its future impact is difficult because laboratory experiments and field observations are limited by their reduced ecologic complexity and sample period, respectively. In contrast, the geological record

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

Science.gov (United States)

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.

Nephrotoxicity of Bence-Jones proteins: interference in renal epithelial cell acidification

Directory of Open Access Journals (Sweden)

Nicastri A.L.

2002-01-01

Full Text Available The aim of the present study was to evaluate the acidification of the endosome-lysosome system of renal epithelial cells after endocytosis of two human immunoglobulin lambda light chains (Bence-Jones proteins, BJP obtained from patients with multiple myeloma. Renal epithelial cell handling of two BJP (neutral and acidic BJP was evaluated by rhodamine fluorescence. Renal cells (MDCK were maintained in culture and, when confluent, were incubated with rhodamine-labeled BJP for different periods of time. Photos were obtained with a fluorescence microscope (Axiolab-Zeiss. Labeling density was determined on slides with a densitometer (Shimadzu Dual-Wavelength Flying-Spot Scanner CS9000. Endocytosis of neutral and acidic BJP was correlated with acidic intracellular compartment distribution using acridine orange labeling. We compared the pattern of distribution after incubation of native neutral and acidic BJP and after complete deglycosylation of BJP by periodate oxidation. The subsequent alteration of pI converted neutral BJP to acidic BJP. There was a significant accumulation of neutral BJP in endocytic structures, reduced lysosomal acidification, and a diffuse pattern of acidification. This pattern was reversed after total deglycosylation and subsequent alteration of the pI to an acidic BJP. We conclude that the physicochemical characteristics of BJP interfere with intracellular acidification, possibly explaining the strong nephrotoxicity of neutral BJP. Lysosomal acidification is fundamental for adequate protein processing and catabolism.

Ocean acidification alters predator behaviour and reduces predation rate.

Science.gov (United States)

Watson, Sue-Ann; Fields, Jennifer B; Munday, Philip L

2017-02-01

Ocean acidification poses a range of threats to marine invertebrates; however, the emerging and likely widespread effects of rising carbon dioxide (CO 2 ) levels on marine invertebrate behaviour are still little understood. Here, we show that ocean acidification alters and impairs key ecological behaviours of the predatory cone snail Conus marmoreus Projected near-future seawater CO 2 levels (975 µatm) increased activity in this coral reef molluscivore more than threefold (from less than 4 to more than 12 mm min -1 ) and decreased the time spent buried to less than one-third when compared with the present-day control conditions (390 µatm). Despite increasing activity, elevated CO 2 reduced predation rate during predator-prey interactions with control-treated humpbacked conch, Gibberulus gibberulus gibbosus; 60% of control predators successfully captured and consumed their prey, compared with only 10% of elevated CO 2 predators. The alteration of key ecological behaviours of predatory invertebrates by near-future ocean acidification could have potentially far-reaching implications for predator-prey interactions and trophic dynamics in marine ecosystems. Combined evidence that the behaviours of both species in this predator-prey relationship are altered by elevated CO 2 suggests food web interactions and ecosystem structure will become increasingly difficult to predict as ocean acidification advances over coming decades. © 2017 The Author(s).

An ontology design pattern for surface water features

Science.gov (United States)

Sinha, Gaurav; Mark, David; Kolas, Dave; Varanka, Dalia; Romero, Boleslo E.; Feng, Chen-Chieh; Usery, E. Lynn; Liebermann, Joshua; Sorokine, Alexandre

2014-01-01

Surface water is a primary concept of human experience but concepts are captured in cultures and languages in many different ways. Still, many commonalities exist due to the physical basis of many of the properties and categories. An abstract ontology of surface water features based only on those physical properties of landscape features has the best potential for serving as a foundational domain ontology for other more context-dependent ontologies. The Surface Water ontology design pattern was developed both for domain knowledge distillation and to serve as a conceptual building-block for more complex or specialized surface water ontologies. A fundamental distinction is made in this ontology between landscape features that act as containers (e.g., stream channels, basins) and the bodies of water (e.g., rivers, lakes) that occupy those containers. Concave (container) landforms semantics are specified in a Dry module and the semantics of contained bodies of water in a Wet module. The pattern is implemented in OWL, but Description Logic axioms and a detailed explanation is provided in this paper. The OWL ontology will be an important contribution to Semantic Web vocabulary for annotating surface water feature datasets. Also provided is a discussion of why there is a need to complement the pattern with other ontologies, especially the previously developed Surface Network pattern. Finally, the practical value of the pattern in semantic querying of surface water datasets is illustrated through an annotated geospatial dataset and sample queries using the classes of the Surface Water pattern.

Ocean acidification alters early successional coral reef communities and their rates of community metabolism.

Directory of Open Access Journals (Sweden)

Sam H C Noonan

Full Text Available 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

How to repel hot water from a superhydrophobic surface?

KAUST Repository

Yu, Zhejun

2014-01-01

Superhydrophobic surfaces, with water contact angles greater than 150° and slide angles less than 10°, have attracted a great deal of attention due to their self-cleaning ability and excellent water-repellency. It is commonly accepted that a superhydrophobic surface loses its superhydrophobicity in contact with water hotter than 50 °C. Such a phenomenon was recently demonstrated by Liu et al. [J. Mater. Chem., 2009, 19, 5602], using both natural lotus leaf and artificial leaf-like surfaces. However, our work has shown that superhydrophobic surfaces maintained their superhydrophobicity, even in water at 80 °C, provided that the leaf temperature is greater than that of the water droplet. In this paper, we report on the wettability of water droplets on superhydrophobic thin films, as a function of both their temperatures. The results have shown that both the water contact and slide angles on the surfaces will remain unchanged when the temperature of the water droplet is greater than that of the surface. The water contact angle, or the slide angle, will decrease or increase, however, with droplet temperatures increasingly greater than that of the surfaces. We propose that, in such cases, the loss of superhydrophobicity of the surfaces is caused by evaporation of the hot water molecules and their condensation on the cooler surface. © 2014 the Partner Organisations.

Adsorption of surface functionalized silica nanoparticles onto mineral surfaces and decane/water interface

International Nuclear Information System (INIS)

Metin, Cigdem O.; Baran, Jimmie R.; Nguyen, Quoc P.

2012-01-01

The adsorption of silica nanoparticles onto representative mineral surfaces and at the decane/water interface was studied. The effects of particle size (the mean diameters from 5 to 75 nm), concentration and surface type on the adsorption were studied in detail. Silica nanoparticles with four different surfaces [unmodified, surface modified with anionic (sulfonate), cationic (quaternary ammonium (quat)) or nonionic (polyethylene glycol (PEG)) surfactant] were used. The zeta potential of these silica nanoparticles ranges from −79.8 to 15.3 mV. The shape of silica particles examined by a Hitachi-S5500 scanning transmission electron microscope (STEM) is quite spherical. The adsorption of all the nanoparticles (unmodified or surface modified) on quartz and calcite surfaces was found to be insignificant. We used interfacial tension (IFT) measurements to investigate the adsorption of silica nanoparticles at the decane/water interface. Unmodified nanoparticles or surface modified ones with sulfonate or quat do not significantly affect the IFT of the decane/water interface. It also does not appear that the particle size or concentration influences the IFT. However, the presence of PEG as a surface modifying material significantly reduces the IFT. The PEG surface modifier alone in an aqueous solution, without the nanoparticles, yields the same IFT reduction for an equivalent PEG concentration as that used for modifying the surface of nanoparticles. Contact angle measurements of a decane droplet on quartz or calcite plate immersed in water (or aqueous nanoparticle dispersion) showed a slight change in the contact angle in the presence of the studied nanoparticles. The results of contact angle measurements are in good agreement with experiments of adsorption of nanoparticles on mineral surfaces or decane/water interface. This study brings new insights into the understanding and modeling of the adsorption of surface-modified silica nanoparticles onto mineral surfaces and

Radioactivity in surface waters and its effects

International Nuclear Information System (INIS)

Stoeber, I.

1987-01-01

In consequence of the reactor accident in Chernobyl, the State Office for Water and Waste Disposal of North-Rhine Westphalia implemented immediate programmes for monitoring radioactivity in surface waters, including their sediments and organisms. Of the initially-measured radionuclides, only cesium-137, with its long half-life of 30 years, is of interest. Only trace amounts of the almost equally long-lived strontium 90 (half-life 28 years) were present in rainfall. Cs-137 is a non-natural-radionuclide, occurring solely as a by-product of nuclear installations and atomic bomb tests. Following the ban on surface testing of nuclear weapons, the Cs-137 content of surface waters had fallen significantly up to April 1986. The load due to the reactor disaster is of the same order of magnitude as that produced by atomic testing at the end of the nineteen-sixties. The paper surveys radioactive pollution of surface waters in North-Rhine Westphalia and its effects on water use, especially in regard to potable water supplies and the fish population. (orig./HSCH) [de

Soil Acidification Aggravates the Occurrence of Bacterial Wilt in South China

Directory of Open Access Journals (Sweden)

Chen Xu

2017-04-01

Full Text Available Soil acidification is a major problem in modern agricultural systems and is an important factor affecting the soil microbial community and soil health. However, little is known about the effect of soil acidification on soil-borne plant diseases. We performed a 4-year investigation in South China to evaluate the correlation between soil acidification and the occurrence of bacterial wilt. The results showed that the average soil pH in fields infected by bacterial wilt disease was much lower than that in non-disease fields. Moreover, the proportion of infected soils with pH lower than 5.5 was much higher than that of non-infected soils, and this phenomenon became more obvious as the area of bacterial wilt disease increased at soil pH lower than 5.5 from 2011 to 2014. Then, in a field pot experiment, bacterial wilt disease developed more quickly and severely in acidic conditions of pH 4.5, 5.0, and 5.5. These results indicate that soil acidification can cause the outbreak of bacterial wilt disease. Further experiments showed that acidic conditions (pH 4.5–5.5 favored the growth of the pathogen Ralstonia solanacearum but suppressed the growth and antagonistic activity of antagonistic bacteria of Pseudomonas fluorescens and Bacillus cereus. Moreover, acidic conditions of pH 5.5 were conducive to the expression of the virulence genes PopA, PrhA, and SolR but restrained resistance gene expression in tobacco. Finally, application of wood ash and lime as soil pH amendments improved soil pH and reduced the occurrence of bacterial wilt. Together, these findings improve our understanding of the correlation between soil acidification and soil-borne plant diseases and also suggest that regulation of soil acidification is the precondition and foundation of controlling bacterial wilt.

Surface-Water Data, Georgia, Water Year 1999

Science.gov (United States)

Alhadeff, S. Jack; Landers, Mark N.; McCallum, Brian E.

1999-01-01

Water resources data for the 1999 water year for Georgia consists of records of stage, discharge, and water quality of streams; and the stage and contents of lakes and reservoirs published in one volume in a digital format on a CD-ROM. This volume contains discharge records of 121 gaging stations; stage for 13 gaging stations; stage and contents for 18 lakes and reservoirs; continuous water quality records for 10 stations; and the annual peak stage and annual peak discharge for 75 crest-stage partial-record stations. These data represent that part of the National Water Data System collected by the U.S. Geological Survey and cooperating State and Federal agencies in Georgia. Records of discharge and stage of streams, and contents or stage of lakes and reservoirs were first published in a series of U.S. Geological water-supply papers entitled, 'Surface-Water Supply of the United States.' Through September 30, 1960, these water-supply papers were in an annual series and then in a 5-year series for 1961-65 and 1966-70. Records of chemical quality, water temperature, and suspended sediment were published from 1941 to 1970 in an annual series of water-supply papers entitled, 'Quality of Surface Waters of the United States.' Records of ground-water levels were published from 1935 to 1974 in a series of water-supply papers entitled, 'Ground-Water Levels in the United States.' Water-supply papers may be consulted in the libraries of the principal cities in the United States or may be purchased from the U.S. Geological Survey, Branch of Information Services, Federal Center, Box 25286, Denver, CO 80225. For water years 1961 through 1970, streamflow data were released by the U.S. Geological Survey in annual reports on a State-boundary basis prior to the two 5-year series water-supply papers, which cover this period. The data contained in the water-supply papers are considered the official record. Water-quality records for water years 1964 through 1970 were similarly released

Transgenerational acclimation of fishes to climate change and ocean acidification

OpenAIRE

Munday, Philip L.

2014-01-01

There is growing concern about the impacts of climate change and ocean acidification on marine organisms and ecosystems, yet the potential for acclimation and adaptation to these threats is poorly understood. Whereas many short-term experiments report negative biological effects of ocean warming and acidification, new studies show that some marine species have the capacity to acclimate to warmer and more acidic environments across generations. Consequently, transgenerational plasticity may be...

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

Science.gov (United States)

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.

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

Directory of Open Access Journals (Sweden)

Laura Fillinger

2013-10-01

Full Text Available 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.

Action plan to counteract soil acidification and to promote sustainable use of forest land

International Nuclear Information System (INIS)

2002-04-01

-year phase of research and method development is both essential and sufficient for obtaining robust criteria for selection of suitable or unsuitable areas, and tools for planning and coordination, e.g., with liming of surface waters. Further, the Board proposes that research and method development into adaptation of silviculture in areas suffering from acidification are initiated and that recommendations are elaborated during this 3-year preparatory phase. The subsequent operative part of the countermeasures, when most of the practical spreading will occur is estimated to take about 10 years. The cost of the 3-year preparatory phase is estimated to be 90 million SEK, plus the cost of the operative phase, which is between 430 and 750 million SEK for the entire 10-year period. The Board of Forestry proposes that the state is responsible for these costs. The lakes and waterways liming programme costs about 210 million SEK annually and today is financed to about 93% by the state and otherwise mainly by individual municipalities. The action plan also aims to improve the conditions for sustainable utilisation of forest land in connection with removal of forest biofuel. The National Board of Forestry is positive to the use of biofuel but considers that measures in the form of follow-ups and extension should be introduced in order to speed up and stimulate the development with regard to nutrient compensation for biomass removal, including whole tree harvest. The cost of the actual nutrient compensation is expected, as formerly, to be dealt with by the actors on the market without financial assistance from the state. On the other hand, the National Board of Forestry proposes that the follow-up and extension inputs are started within the framework of the action plan and thereby obtain state financing. The action plan contributes directly to fulfilment of the national environmental goals 'Only natural acidification', 'Living lakes and waterways' and 'Living forests'. The plan also

Transcriptomic response of the Antarctic pteropod Limacina helicina antarctica to ocean acidification.

Science.gov (United States)

Johnson, Kevin M; Hofmann, Gretchen E

2017-10-23

Ocean acidification (OA), a change in ocean chemistry due to the absorption of atmospheric CO 2 into surface oceans, challenges biogenic calcification in many marine organisms. Ocean acidification is expected to rapidly progress in polar seas, with regions of the Southern Ocean expected to experience severe OA within decades. Biologically, the consequences of OA challenge calcification processes and impose an energetic cost. In order to better characterize the response of a polar calcifier to conditions of OA, we assessed differential gene expression in the Antarctic pteropod, Limacina helicina antarctica. Experimental levels of pCO 2 were chosen to create both contemporary pH conditions, and to mimic future pH expected in OA scenarios. Significant changes in the transcriptome were observed when juvenile L. h. antarctica were acclimated for 21 days to low-pH (7.71), mid-pH (7.9) or high-pH (8.13) conditions. Differential gene expression analysis of individuals maintained in the low-pH treatment identified down-regulation of genes involved in cytoskeletal structure, lipid transport, and metabolism. High pH exposure led to increased expression and enrichment for genes involved in shell formation, calcium ion binding, and DNA binding. Significant differential gene expression was observed in four major cellular and physiological processes: shell formation, the cellular stress response, metabolism, and neural function. Across these functional groups, exposure to conditions that mimic ocean acidification led to rapid suppression of gene expression. Results of this study demonstrated that the transcriptome of the juvenile pteropod, L. h. antarctica, was dynamic and changed in response to different levels of pCO 2 . In a global change context, exposure of L. h. antarctica to the low pH, high pCO 2 OA conditions resulted in a suppression of transcripts for genes involved in key physiological processes: calcification, metabolism, and the cellular stress response. The

Arctic ocean acidification: pelagic ecosystem and biogeochemical responses during a mesocosm study

NARCIS (Netherlands)

Riebesell, U.; Gattuso, J.-P.; Thingstad, T.F.; Middelburg, J.J.

2013-01-01

The growing evidence of potential biological impacts of ocean acidification affirms that this global change phenomenon may pose a serious threat to marine organisms and ecosystems. Whilst ocean acidification will occur everywhere, it will happen more rapidly in some regions than in others. Due

Lithium content in potable water, surface water, ground water, and mineral water on the territory of Republic of Macedonia

OpenAIRE

Kostik, Vesna; Bauer, Biljana; Kavrakovski, Zoran

2014-01-01

The aim of this study was to determine lithium concentration in potable water, surface water, ground, and mineral water on the territory of the Republic of Macedonia. Water samples were collected from water bodies such as multiple public water supply systems located in 13 cities, wells boreholes located in 12 areas, lakes and rivers located in three different areas. Determination of lithium concentration in potable water, surface water was performed by the technique of inductively coupl...

Presence and risk assessment of pharmaceuticals in surface water and drinking water

DEFF Research Database (Denmark)

Sanderson, Hans

2011-01-01

Trace amounts of pharmaceuticals have been detected in surface waters in the nano- to microgram per liter range, and in drinking water in the nanogram/L range. The environmental risks of pharmaceuticals in surface waters have been evaluated and generally found to be low if the wastewater is treated...

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

Science.gov (United States)

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.

Anomalous water dynamics at surfaces and interfaces: synergistic effects of confinement and surface interactions

Science.gov (United States)

Biswas, Rajib; Bagchi, Biman

2018-01-01

In nature, water is often found in contact with surfaces that are extended on the scale of molecule size but small on a macroscopic scale. Examples include lipid bilayers and reverse micelles as well as biomolecules like proteins, DNA and zeolites, to name a few. While the presence of surfaces and interfaces interrupts the continuous hydrogen bond network of liquid water, confinement on a mesoscopic scale introduces new features. Even when extended on a molecular scale, natural and biological surfaces often have features (like charge, hydrophobicity) that vary on the scale of the molecular diameter of water. As a result, many new and exotic features, which are not seen in the bulk, appear in the dynamics of water close to the surface. These different behaviors bear the signature of both water-surface interactions and of confinement. In other words, the altered properties are the result of the synergistic effects of surface-water interactions and confinement. Ultrafast spectroscopy, theoretical modeling and computer simulations together form powerful synergistic approaches towards an understanding of the properties of confined water in such systems as nanocavities, reverse micelles (RMs), water inside and outside biomolecules like proteins and DNA, and also between two hydrophobic walls. We shall review the experimental results and place them in the context of theory and simulations. For water confined within RMs, we discuss the possible interference effects propagating from opposite surfaces. Similar interference is found to give rise to an effective attractive force between two hydrophobic surfaces immersed and kept fixed at a separation of d, with the force showing an exponential dependence on this distance. For protein and DNA hydration, we shall examine a multitude of timescales that arise from frustration effects due to the inherent heterogeneity of these surfaces. We pay particular attention to the role of orientational correlations and modification of the

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

International Nuclear Information System (INIS)

Cravotta, C.A. III

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 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

Monitoring structure development in milk acidification using diffuse reflectance profiles

DEFF Research Database (Denmark)

Skytte, Jacob Lercke; Andersen, Ulf; Møller, Flemming

2012-01-01

are needed so that the production can be carried out consistently, regardless of day-to-day variations in the raw materials. Casein micelles aggregate during milk acidification, which leads to formation of a gel network. This change of structure is important for the development of a range of dairy products......, protein, and temperature in the acidification process is conducted. The purpose of the experiment is to investigate how the change of these parameters affects the diffuse reflectance properties as well as to demonstrate the relation between the optical parameters and structure formation in milk......The structure of dairy products is important for the consumer, and milk acidification plays a central role for structural development. To ensure the best possible consumer experience, it is important that a product’s structural properties are stable. Therefore process and quality control tools...

40 CFR 257.3-3 - Surface water.

Science.gov (United States)

2010-07-01

... 40 Protection of Environment 24 2010-07-01 2010-07-01 false Surface water. 257.3-3 Section 257.3-3... and Practices § 257.3-3 Surface water. (a) For purposes of section 4004(a) of the Act, a facility... Water Act, as amended. (b) For purposes of section 4004(a) of the Act, a facility shall not cause a...

Oxidative stress in the hydrocoral Millepora alcicornis exposed to CO2-driven seawater acidification

Science.gov (United States)

Luz, Débora Camacho; Zebral, Yuri Dornelles; Klein, Roberta Daniele; Marques, Joseane Aparecida; Marangoni, Laura Fernandes de Barros; Pereira, Cristiano Macedo; Duarte, Gustavo Adolpho Santos; Pires, Débora de Oliveira; Castro, Clovis Barreira e.; Calderon, Emiliano Nicolas; Bianchini, Adalto

2018-06-01

Global impacts are affecting negatively coral reefs' health worldwide. Ocean acidification associated with the increasing CO2 partial pressure in the atmosphere can potentially induce oxidative stress with consequent cellular damage in corals and hydrocorals. In the present study, parameters related to oxidative status were evaluated in the hydrocoral Millepora alcicornis exposed to three different levels of seawater acidification using a mesocosm system. CO2-driven acidification of seawater was performed until reaching 0.3, 0.6 and 0.9 pH units below the current pH of seawater pumped from the coral reef adjacent to the mesocosm. Therefore, treatments corresponded to control (pH 8.1), mild (pH 7.8), intermediate (pH 7.5) and severe (pH 7.2) seawater acidification. After 0, 16 and 30 d of exposure, hydrocorals were collected and the following parameters were analyzed in the holobiont: antioxidant capacity against peroxyl radicals (ACAP), total glutathione (GSHt) concentration, reduced (GSH) and oxidized (GSSG) glutathione ratio (GSH/GSSG), lipid peroxidation (LPO) and protein carbonyl group (PC) levels. ACAP was increased in hydrocorals after 16 d of exposure to intermediate levels of seawater acidification. GSHt and GSH/GSSG did not change over the experimental period. LPO was increased at any level of seawater acidification, while PC content was increased in hydrocorals exposed to intermediate and severe seawater acidification for 30 d. These findings indicate that the antioxidant defense system of M. alcicornis is capable of coping with acidic conditions for a short period of time (16 d). Additionally, they clearly show that a long-term (30 d) exposure to seawater acidification induces oxidative stress with consequent oxidative damage to lipids and proteins, which could compromise hydrocoral health.

Is acidification still a major air pollution concern?; L`acidification est-elle encore un probleme majeur de pollution atmospherique?

Energy Technology Data Exchange (ETDEWEB)

NONE

1997-12-31

Although other forms of long-range air pollution are gaining attention, acidification remains an important issue in certain parts of Europe as well as in other continents. In spite of the European 88/609 directive limiting acid emissions from large fuel burning plants, a large part of Europe soils receives acid deposits superior to the tolerance threshold, known as critical loads. Thus, the European Union is considering several new measures, such as a more drastic 88/609 directive, the limitation of emissions country by country, the limitation of sulfur content in heavy fuels, etc. Emission inventories, evaluation tools, long range transfrontier pollution models, integrated assessment, etc. are presented, together with the positions of various French governmental departments, public authorities and industries concerning the european strategy against acidification

Atmospheric Water Harvesting: Role of Surface Wettability and Edge Effect

KAUST Repository

Jin, Yong

2017-06-23

Atmospheric water is emerging as an important potable water source. The present work experimentally and theoretically investigates water condensation and collection on flat surfaces with contrasting contact angles and contact angle hysteresis (CAH) to elucidate their roles on water mass collection efficiency. The experimental results indicate that a hydrophilic surface promotes nucleation and individual droplets growth, and a surface with a low CAH tends to let a smaller droplet to slide down, but the overall water mass collection efficiency is independent of both surface contact angle and CAH. The experimental results agree well with our theoretical calculations. During water condensation, a balance has to be struck between single droplet growth and droplet density on a surface so as to maintain a constant water droplet surface coverage ratio, which renders the role of both surface wettability and hysteresis insignificant to the ultimate water mass collection. Moreover, water droplets on the edges of a surface grow much faster than those on the non-edge areas and thus dominate the contribution to the water mass collection by the entire surface, directly pointing out the very important role of edge effect on water condensation and collection.

Reduced European emissions of S and N - Effects on air concentrations, deposition and soil water chemistry in Swedish forests

Energy Technology Data Exchange (ETDEWEB)

Pihl Karlsson, Gunilla, E-mail: gunilla.pihl.karlsson@ivl.se [IVL Swedish Environmental Research Institute, Box 5302, SE-400 14 Gothenburg (Sweden); Akselsson, Cecilia, E-mail: cecilia.akselsson@nateko.lu.se [Department of Earth and Ecosystem Sciences, Lund University, Soelvegatan 12, SE-223 62 Lund (Sweden); Hellsten, Sofie, E-mail: sofie.hellsten@ivl.se [IVL Swedish Environmental Research Institute, Box 5302, SE-400 14 Gothenburg (Sweden); Karlsson, Per Erik, E-mail: pererik.karlsson@ivl.se [IVL Swedish Environmental Research Institute, Box 5302, SE-400 14 Gothenburg (Sweden)

2011-12-15

Changes in sulphur and nitrogen pollution in Swedish forests have been assessed in relation to European emission reductions, based on measurements in the Swedish Throughfall Monitoring Network. Measurements were analysed over 20 years with a focus on the 12-year period 1996 to 2008. Air concentrations of SO{sub 2} and NO{sub 2}, have decreased. The SO{sub 4}-deposition has decreased in parallel with the European emission reductions. Soil water SO{sub 4}-concentrations have decreased at most sites but the pH, ANC and inorganic Al-concentrations indicated acidification recovery only at some of the sites. No changes in the bulk deposition of inorganic nitrogen could be demonstrated. Elevated NO{sub 3}-concentrations in the soil water occurred at irregular occasions at some southern sites. Despite considerable air pollution emission reductions in Europe, acidification recovery in Swedish forests soils is slow. Nitrogen deposition to Swedish forests continues at elevated levels that may lead to leaching of nitrate to surface waters. - Highlights: > S deposition to Swedish forests has decreased in parallel with European emissions. > Soil water pH, ANC and inorganic Al-concentrations indicated a slow recovery. > The bulk deposition of inorganic nitrogen over Sweden has not decreased. > Continued N deposition to Swedish forests may cause leaching of N to surface waters. - Reduced European emissions have led to decreased acidic deposition and a slow recovery of soil water but nitrogen deposition remains the same in Swedish forests.

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

Science.gov (United States)

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.

Modelling global fresh surface water temperature

NARCIS (Netherlands)

Beek, L.P.H. van; Eikelboom, T.; Vliet, M.T.H. van; Bierkens, M.F.P.

2011-01-01

Temperature directly determines a range of water physical properties including vapour pressure, surface tension, density and viscosity, and the solubility of oxygen and other gases. Indirectly water temperature acts as a strong control on fresh water biogeochemistry, influencing sediment

Smog nitrogen and the rapid acidification of forest soil, San Bernardino Mountains, southern California.

Science.gov (United States)

Wood, Yvonne A; Fenn, Mark; Meixner, Thomas; Shouse, Peter J; Breiner, Joan; Allen, Edith; Wu, Laosheng

2007-03-21

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 approximately 130 cm of soil where it accumulates and increases soil acidity.

Smog Nitrogen and the Rapid Acidification of Forest Soil, San Bernardino Mountains, Southern California

Directory of Open Access Journals (Sweden)

Yvonne A. Wood

2007-01-01

Full Text Available 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.

Determination of the acidification state of Canadian Pacific coastal waters using empirical relationships with hydrographic data

Science.gov (United States)

Lara Espinosa, Alejandra

to be insensitive to changes in spatial domain or interannual variability in the data. These results suggest that the model can be used to estimate the distribution of Oarag along the outer west coast of Canada when basic hydrographic data on temperature and O2 are available. Predictions of Oarag from historical observations (1980-2009) in this region reveal that the saturation horizon (Oarag=1) tended to be more stable in winter and spring and highly variable and occasionally shallow in summer and fall during and following the upwelling season. Undersaturation with respect to aragonite was more likely to occur at shallower depths over the shelf relative to adjacent offshore waters likely as a result of upwelling. The Oarag saturation horizon tended to be more variable in depth on the shelf compared to offshore waters. The saturation horizon tended to occur at deeper depths over the Queen Charlotte Sound (QCS) shelf and be more stable with respect to the west coast of Vancouver island (WCVI). Thus, the WCVI may experience adverse effects of ocean acidification more acutely than QCS. The use of this approach may provide insight into natural variability and the key controls of O arag in future studies at a low cost. However, this predictive model cannot hind-cast data to evaluate the presence of the anthropogenic signal.

An Ontology Design Pattern for Surface Water Features

Energy Technology Data Exchange (ETDEWEB)

Sinha, Gaurav [Ohio University; Mark, David [University at Buffalo (SUNY); Kolas, Dave [Raytheon BBN Technologies; Varanka, Dalia [U.S. Geological Survey, Rolla, MO; Romero, Boleslo E [University of California, Santa Barbara; Feng, Chen-Chieh [National University of Singapore; Usery, Lynn [U.S. Geological Survey, Rolla, MO; Liebermann, Joshua [Tumbling Walls, LLC; Sorokine, Alexandre [ORNL

2014-01-01

Surface water is a primary concept of human experience but concepts are captured in cultures and languages in many different ways. Still, many commonalities can be found due to the physical basis of many of the properties and categories. An abstract ontology of surface water features based only on those physical properties of landscape features has the best potential for serving as a foundational domain ontology. It can then be used to systematically incor-porate concepts that are specific to a culture, language, or scientific domain. The Surface Water ontology design pattern was developed both for domain knowledge distillation and to serve as a conceptual building-block for more complex surface water ontologies. A fundamental distinction is made in this on-tology between landscape features that act as containers (e.g., stream channels, basins) and the bodies of water (e.g., rivers, lakes) that occupy those containers. Concave (container) landforms semantics are specified in a Dry module and the semantics of contained bodies of water in a Wet module. The pattern is imple-mented in OWL, but Description Logic axioms and a detailed explanation is provided. The OWL ontology will be an important contribution to Semantic Web vocabulary for annotating surface water feature datasets. A discussion about why there is a need to complement the pattern with other ontologies, es-pecially the previously developed Surface Network pattern is also provided. Fi-nally, the practical value of the pattern in semantic querying of surface water datasets is illustrated through a few queries and annotated geospatial datasets.

Impacts of ocean acidification on marine organisms: quantifying sensitivities and interaction with warming

Science.gov (United States)

Kroeker, Kristy J; Kordas, Rebecca L; Crim, Ryan; Hendriks, Iris E; Ramajo, Laura; Singh, Gerald S; Duarte, Carlos M; Gattuso, Jean-Pierre

2013-01-01

Ocean acidification represents a threat to marine species worldwide, and forecasting the ecological impacts of acidification is a high priority for science, management, and policy. As research on the topic expands at an exponential rate, a comprehensive understanding of the variability in organisms' responses and corresponding levels of certainty is necessary to forecast the ecological effects. Here, we perform the most comprehensive meta-analysis to date by synthesizing the results of 228 studies examining biological responses to ocean acidification. The results reveal decreased survival, calcification, growth, development and abundance in response to acidification when the broad range of marine organisms is pooled together. However, the magnitude of these responses varies among taxonomic groups, suggesting there is some predictable trait-based variation in sensitivity, despite the investigation of approximately 100 new species in recent research. The results also reveal an enhanced sensitivity of mollusk larvae, but suggest that an enhanced sensitivity of early life history stages is not universal across all taxonomic groups. In addition, the variability in species' responses is enhanced when they are exposed to acidification in multi-species assemblages, suggesting that it is important to consider indirect effects and exercise caution when forecasting abundance patterns from single-species laboratory experiments. Furthermore, the results suggest that other factors, such as nutritional status or source population, could cause substantial variation in organisms' responses. Last, the results highlight a trend towards enhanced sensitivity to acidification when taxa are concurrently exposed to elevated seawater temperature. PMID:23505245

Effects of hypoxia and ocean acidification on the upper thermal niche boundaries of coral reef fishes.

Science.gov (United States)

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).

Surface-Water Conditions in Georgia, Water Year 2005

Science.gov (United States)

Painter, Jaime A.; Landers, Mark N.

2007-01-01

INTRODUCTION The U.S. Geological Survey (USGS) Georgia Water Science Center-in cooperation with Federal, State, and local agencies-collected surface-water streamflow, water-quality, and ecological data during the 2005 Water Year (October 1, 2004-September 30, 2005). These data were compiled into layers of an interactive ArcReaderTM published map document (pmf). ArcReaderTM is a product of Environmental Systems Research Institute, Inc (ESRI?). Datasets represented on the interactive map are * continuous daily mean streamflow * continuous daily mean water levels * continuous daily total precipitation * continuous daily water quality (water temperature, specific conductance dissolved oxygen, pH, and turbidity) * noncontinuous peak streamflow * miscellaneous streamflow measurements * lake or reservoir elevation * periodic surface-water quality * periodic ecological data * historical continuous daily mean streamflow discontinued prior to the 2005 water year The map interface provides the ability to identify a station in spatial reference to the political boundaries of the State of Georgia and other features-such as major streams, major roads, and other collection stations. Each station is hyperlinked to a station summary showing seasonal and annual stream characteristics for the current year and for the period of record. For continuous discharge stations, the station summary includes a one page graphical summary page containing five graphs, a station map, and a photograph of the station. The graphs provide a quick overview of the current and period-of-record hydrologic conditions of the station by providing a daily mean discharge graph for the water year, monthly statistics graph for the water year and period of record, an annual mean streamflow graph for the period of record, an annual minimum 7-day average streamflow graph for the period of record, and an annual peak streamflow graph for the period of record. Additionally, data can be accessed through the layer's link

Transport and transformation of surface water masses across the ...

African Journals Online (AJOL)

Transport and transformation of surface water masses across the Mascarene Plateau during the Northeast Monsoon season. ... Mixing occurs in the central gap between intermediate water masses (Red Sea Water [RSW] and Antarctic Intermediate Water [AAIW]) as well as in the upper waters (Subtropical Surface Water ...

Respiration of Mediterranean cold-water corals is not affected by ocean acidification as projected for the end of the century

Science.gov (United States)

Maier, C.; Bils, F.; Weinbauer, M. G.; Watremez, P.; Peck, M. A.; Gattuso, J.-P.

2013-08-01

The rise of CO2 has been identified as a major threat to life in the ocean. About one-third of the anthropogenic CO2 produced in the last 200 yr has been taken up by the ocean, leading to ocean acidification. Surface seawater pH is projected to decrease by about 0.4 units between the pre-industrial revolution and 2100. The branching cold-water corals Madrepora oculata and Lophelia pertusa are important, habitat-forming species in the deep Mediterranean Sea. Although previous research has investigated the abundance and distribution of these species, little is known regarding their ecophysiology and potential responses to global environmental change. A previous study indicated that the rate of calcification of these two species remained constant up to 1000 μatm CO2, a value that is at the upper end of changes projected to occur by 2100. We examined whether the ability to maintain calcification rates in the face of rising pCO2 affected the energetic requirements of these corals. Over the course of three months, rates of respiration were measured at a pCO2 ranging between 350 and 1100 μatm to distinguish between short-term response and longer-term acclimation. Respiration rates ranged from 0.074 to 0.266 μmol O2 (g skeletal dry weight)-1 h-1 and 0.095 to 0.725 μmol O2 (g skeletal dry weight)-1 h-1 for L. pertusa and M. oculata, respectively, and were independent of pCO2. Respiration increased with time likely due to regular feeding, which may have provided an increased energy supply to sustain coral metabolism. Future studies are needed to confirm whether the insensitivity of respiration to increasing pCO2 is a general feature of deep-sea corals in other regions.

Respiration of Mediterranean cold-water corals is not affected by ocean acidification as projected for the end of the century

Directory of Open Access Journals (Sweden)

C. Maier

2013-08-01

Full Text Available The rise of CO2 has been identified as a major threat to life in the ocean. About one-third of the anthropogenic CO2 produced in the last 200 yr has been taken up by the ocean, leading to ocean acidification. Surface seawater pH is projected to decrease by about 0.4 units between the pre-industrial revolution and 2100. The branching cold-water corals Madrepora oculata and Lophelia pertusa are important, habitat-forming species in the deep Mediterranean Sea. Although previous research has investigated the abundance and distribution of these species, little is known regarding their ecophysiology and potential responses to global environmental change. A previous study indicated that the rate of calcification of these two species remained constant up to 1000 μatm CO2, a value that is at the upper end of changes projected to occur by 2100. We examined whether the ability to maintain calcification rates in the face of rising pCO2 affected the energetic requirements of these corals. Over the course of three months, rates of respiration were measured at a pCO2 ranging between 350 and 1100 μatm to distinguish between short-term response and longer-term acclimation. Respiration rates ranged from 0.074 to 0.266 μmol O2 (g skeletal dry weight−1 h−1 and 0.095 to 0.725 μmol O2 (g skeletal dry weight−1 h−1 for L. pertusa and M. oculata, respectively, and were independent of pCO2. Respiration increased with time likely due to regular feeding, which may have provided an increased energy supply to sustain coral metabolism. Future studies are needed to confirm whether the insensitivity of respiration to increasing pCO2 is a general feature of deep-sea corals in other regions.

Surface water quality assessment using factor analysis

African Journals Online (AJOL)

2006-01-16

Jan 16, 2006 ... Surface water, groundwater quality assessment and environ- .... Urbanisation influences the water cycle through changes in flow and water ..... tion of aquatic life, CCME water quality Index 1, 0. User`s ... Water, Air Soil Pollut.

Treatment of black liquor from the papermaking industry by acidification and reuse.

Science.gov (United States)

Yang, Wen-Bo; Mu, Huan-Zhen; Huang, Yan-Chu

2003-09-01

Two different kinds of black liquor from the papermaking industry were treated by acidification and reuse. The experimental parameters and conditions were discussed in detail. The experimental results indicated that the treatment process mentioned in this article is an effective process for the treatment of black liquor from the papermaking industry. By the treatment, the solid materials in black liquor are transferred into two by-products and the other components are reused or evaporated. Thus, no wastewater except some condensation water would be discharged in pulping process and the problem of pollution of black liquor would be effectively solved.

Acidification of the osteoclastic resorption compartment provides insight into the coupling of bone formation to bone resorption

DEFF Research Database (Denmark)

Karsdal, M.A.; Henriksen, K.; Sorensen, M.G.

2005-01-01

Patients with defective osteoclastic acidification have increased numbers of osteoclasts, with decreased resorption, but bone formation that remains unchanged. We demonstrate that osteoclast survival is increased when acidification is impaired, and that impairment of acidification results in inhi...

Soil acidification in China: is controlling SO2 emissions enough?

Science.gov (United States)

Zhao, Yu; Duan, Lei; Xing, Jia; Larssen, Thorjorn; Nielsen, Chris P; Hao, Jiming

2009-11-01

Facing challenges of increased energy consumption and related regional air pollution, China has been aggressively implementing flue gas desulfurization (FGD) and phasing out small inefficient units in the power sector in order to achieve the national goal of 10% reduction in sulfur dioxide (SO(2)) emissions from 2005 to 2010. In this paper, the effect of these measures on soil acidification is explored. An integrated methodology is used, combining emission inventory data, emission forecasts, air quality modeling, and ecological sensitivities indicated by critical load. National emissions of SO(2), oxides of nitrogen (NO(X)), particulate matter (PM), and ammonia (NH(3)) in 2005 were estimated to be 30.7, 19.6, 31.3, and 16.6 Mt, respectively. Implementation of existing policy will lead to reductions in SO(2) and PM emissions, while those of NO(X) and NH(3) will continue to rise, even under tentatively proposed control measures. In 2005, the critical load for soil acidification caused by sulfur (S) deposition was exceeded in 28% of the country's territory, mainly in eastern and south-central China. The area in exceedance will decrease to 26% and 20% in 2010 and 2020, respectively, given implementation of current plans for emission reductions. However, the exceedance of the critical load for nitrogen (N, combining effects of eutrophication and acidification) will double from 2005 to 2020 due to increased NO(X) and NH(3) emissions. Combining the acidification effects of S and N, the benefits of SO(2) reductions during 2005-2010 will almost be negated by increased N emissions. Therefore abatement of N emissions (NO(X) and NH(3)) and deposition will be a major challenge to China, requiring policy development and technology investments. To mitigate acidification in the future, China needs a multipollutant control strategy that integrates measures to reduce S, N, and PM.

Institutional misfit and environmental change: A systems approach to address ocean acidification.

Science.gov (United States)

Ekstrom, Julia A; Crona, Beatrice I

2017-01-15

Emerging environmental threats often lack sufficient governance to address the full extent of the problem. An example is ocean acidification which is a growing concern in fishing and aquaculture economies worldwide, but has remained a footnote in environmental policy at all governance levels. However, existing legal jurisdictions do account for some aspects of the system relating to ocean acidification and these may be leveraged to support adapting to and mitigating ocean acidification. We refine and apply a methodological framework that helps objectively evaluate governance, from a social-ecological systems perspective. We assess how well a set of extant US institutions fits with the social-ecological interactions pertinent to ocean acidification. The assessment points to measured legal gaps, for which we evaluate the government authorities most appropriate to help fill these gaps. The analysis is conducted on United State federal statutes and regulations. Results show quantitative improvement of institutional fit over time (2006 to 2013), but a substantial number of measured legal gaps persist especially around acknowledging local sources of acidification and adaptation strategies to deal with or avoid impacts. We demonstrate the utility of this framework to evaluate the governance surrounding any emerging environmental threat as a first step to guiding the development of jurisdictionally realistic solutions. Copyright © 2016 Elsevier B.V. All rights reserved.

Combined Effect of Ocean Acidification and Seawater Freshening: Response of Pteropod Swimming Behavior

Science.gov (United States)

Manno, C.; Morata, N.; Primicerio, R.

2012-12-01

Increasing anthropogenic carbon dioxide emissions induce ocean acidification. 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 Limacina 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. Survival, shell degradation and swimming behavior were investigated. Mortality 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 where they decreasing the locomotory speed upwards and increasing the wing beats. Results suggest that, the extra energy cost due to maintaining of body fluids and to avoid sinking (in low salinity scenario) combined with the extra energy cost necessary to counteract the dissolution (in high pCO2 scenario), exceeds the available energy budget of this organism and then pteropods change in swimming behavior and begin to collapse. Since Limacina 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.

Rapid surface-water volume estimations in beaver ponds

Science.gov (United States)

Karran, Daniel J.; Westbrook, Cherie J.; Wheaton, Joseph M.; Johnston, Carol A.; Bedard-Haughn, Angela

2017-02-01

Beaver ponds are surface-water features that are transient through space and time. Such qualities complicate the inclusion of beaver ponds in local and regional water balances, and in hydrological models, as reliable estimates of surface-water storage are difficult to acquire without time- and labour-intensive topographic surveys. A simpler approach to overcome this challenge is needed, given the abundance of the beaver ponds in North America, Eurasia, and southern South America. We investigated whether simple morphometric characteristics derived from readily available aerial imagery or quickly measured field attributes of beaver ponds can be used to approximate surface-water storage among the range of environmental settings in which beaver ponds are found. Studied were a total of 40 beaver ponds from four different sites in North and South America. The simplified volume-area-depth (V-A-h) approach, originally developed for prairie potholes, was tested. With only two measurements of pond depth and corresponding surface area, this method estimated surface-water storage in beaver ponds within 5 % on average. Beaver pond morphometry was characterized by a median basin coefficient of 0.91, and dam length and pond surface area were strongly correlated with beaver pond storage capacity, regardless of geographic setting. These attributes provide a means for coarsely estimating surface-water storage capacity in beaver ponds. Overall, this research demonstrates that reliable estimates of surface-water storage in beaver ponds only requires simple measurements derived from aerial imagery and/or brief visits to the field. Future research efforts should be directed at incorporating these simple methods into both broader beaver-related tools and catchment-scale hydrological models.

Physiological responses to ocean acidification and warming synergistically reduce condition of the common cockle Cerastoderma edule.

Science.gov (United States)

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.

Long-term patterns in soil acidification due to pollution in forests of the Eastern Sudetes Mountains

International Nuclear Information System (INIS)

Hedl, Radim; Petrik, Petr; Boublik, Karel

2011-01-01

Soil acidification was assessed in the Eastern Sudetes Mountains (Czech Republic) between 1941 and 2003, i.e. before and after the period of major industrial pollution (1950s-1990s). The twenty sites included in our study were distributed along a gradient of altitude ranging 1000 m. Values of pH have decreased in 80-90% of the pairs of samples after the six decades, on average by 0.7 for pH-H 2 O and 0.6 for pH-KCl. Organic matter increased in the topsoil, probably reflecting a change in decomposition conditions. The most important finding is that the acidification varies along the joint gradient of altitude/tree layer composition, and displays a changing pattern in three soil horizons (A, B and C). Contrary to expectations, most acidified were soils in beech forests at lower elevations. - Highlights: → Soil acidification varies along the joint gradient of altitude/tree composition. → Soil acidification displays a changing pattern in topsoil and subsoil horizons. → Acidification rate is stronger in soils of beech forests at lower elevation. → Historical measurements provide a reliable evidence of long-term soil acidification. - Strong acidification decreasing with altitude was observed in forest soils resurveyed after more than half a century.

Global modelling of Cryptosporidium in surface water

Science.gov (United States)

Vermeulen, Lucie; Hofstra, Nynke

2016-04-01

Introduction Waterborne pathogens that cause diarrhoea, such as Cryptosporidium, pose a health risk all over the world. In many regions quantitative information on pathogens in surface water is unavailable. Our main objective is to model Cryptosporidium concentrations in surface waters worldwide. We present the GloWPa-Crypto model and use the model in a scenario analysis. A first exploration of global Cryptosporidium emissions to surface waters has been published by Hofstra et al. (2013). Further work has focused on modelling emissions of Cryptosporidium and Rotavirus to surface waters from human sources (Vermeulen et al 2015, Kiulia et al 2015). A global waterborne pathogen model can provide valuable insights by (1) providing quantitative information on pathogen levels in data-sparse regions, (2) identifying pathogen hotspots, (3) enabling future projections under global change scenarios and (4) supporting decision making. Material and Methods GloWPa-Crypto runs on a monthly time step and represents conditions for approximately the year 2010. The spatial resolution is a 0.5 x 0.5 degree latitude x longitude grid for the world. We use livestock maps (http://livestock.geo-wiki.org/) combined with literature estimates to calculate spatially explicit livestock Cryptosporidium emissions. For human Cryptosporidium emissions, we use UN population estimates, the WHO/UNICEF JMP sanitation country data and literature estimates of wastewater treatment. We combine our emissions model with a river routing model and data from the VIC hydrological model (http://vic.readthedocs.org/en/master/) to calculate concentrations in surface water. Cryptosporidium survival during transport depends on UV radiation and water temperature. We explore pathogen emissions and concentrations in 2050 with the new Shared Socio-economic Pathways (SSPs) 1 and 3. These scenarios describe plausible future trends in demographics, economic development and the degree of global integration. Results and

Anaerobic acidification of sugar-containing wastewater for biotechnological production of organic acids and ethanol.

Science.gov (United States)

Darwin; Charles, Wipa; Cord-Ruwisch, Ralf

2018-05-03

Anaerobic acidification of sugars can produce some useful end-products such as alcohol, volatile fatty acids (e.g. acetate, propionate, and butyrate) and lactic acid. The production of end-products is highly dependent on factors including pH, temperature, hydraulic retention time and the types of sugar being fermented. Results of this current study indicate that the pH and hydraulic retention time played significant roles in determining the end products from the anaerobic acidification of maltose and glucose. Under uncontrolled pH, the anaerobic acidification of maltose ceased when pH in the reactor dropped below 5 while anaerobic acidification of glucose continued and produced ethanol as the main end-product. Under controlled pH, lactic acid was found to be the dominant end-product produced from both maltose and glucose at pH 5. Acetate was the main end-product from both maltose and glucose fermented at neutral pH (6 and 7). Short hydraulic retention time (HRT) of 2 days could induce the production of ethanol from the anaerobic acidification of glucose. However, the anaerobic acidification of maltose could stop when short HRT of 2 days was applied in the reactor. This finding is significant for industrial fermentation and waste management systems, and selective production of different types of organic acids could be achieved by managing pH and HRT in the reactor.

Extreme ocean acidification reduces the susceptibility of eastern oyster shells to a polydorid parasite.

Science.gov (United States)

Clements, J C; Bourque, D; McLaughlin, J; Stephenson, M; Comeau, L A

2017-11-01

Ocean acidification poses a threat to marine organisms. While the physiological and behavioural effects of ocean acidification have received much attention, the effects of acidification on the susceptibility of farmed shellfish to parasitic infections are poorly understood. Here we describe the effects of moderate (pH 7.5) and extreme (pH 7.0) ocean acidification on the susceptibility of Crassostrea virginica shells to infection by a parasitic polydorid, Polydora websteri. Under laboratory conditions, shells were exposed to three pH treatments (7.0, 7.5 and 8.0) for 3- and 5-week periods. Treated shells were subsequently transferred to an oyster aquaculture site (which had recently reported an outbreak of P. websteri) for 50 days to test for effects of pH and exposure time on P. websteri recruitment to oyster shells. Results indicated that pH and exposure time did not affect the length, width or weight of the shells. Interestingly, P. websteri counts were significantly lower under extreme (pH 7.0; ~50% reduction), but not moderate (pH 7.5; ~20% reduction) acidification levels; exposure time had no effect. This study suggests that extreme levels - but not current and projected near-future levels - of acidification (∆pH ~1 unit) can reduce the susceptibility of eastern oyster shells to P. websteri infections. © 2017 John Wiley & Sons Ltd.

Ocean acidification changes the structure of an Antarctic coastal protistan community

Directory of Open Access Journals (Sweden)

A. M. Hancock

2018-04-01

Full Text Available 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.

Climate change and ocean acidification impacts on lower trophic levels and the export of organic carbon to the deep ocean

Directory of Open Access Journals (Sweden)

A. Yool

2013-09-01

Full Text Available Most future projections forecast significant and ongoing climate change during the 21st century, but with the severity of impacts dependent on efforts to restrain or reorganise human activity to limit carbon dioxide (CO2 emissions. A major sink for atmospheric CO2, and a key source of biological resources, the World Ocean is widely anticipated to undergo profound physical and – via ocean acidification – chemical changes as direct and indirect results of these emissions. Given strong biophysical coupling, the marine biota is also expected to experience strong changes in response to this anthropogenic forcing. Here we examine the large-scale response of ocean biogeochemistry to climate and acidification impacts during the 21st century for Representative Concentration Pathways (RCPs 2.6 and 8.5 using an intermediate complexity global ecosystem model, MEDUSA-2.0. The primary impact of future change lies in stratification-led declines in the availability of key nutrients in surface waters, which in turn leads to a global decrease (1990s vs. 2090s in ocean productivity (−6.3%. This impact has knock-on consequences for the abundance of the low trophic level biogeochemical actors modelled by MEDUSA-2.0 (−5.8%, and these would be expected to similarly impact higher trophic level elements such as fisheries. Related impacts are found in the flux of organic material to seafloor communities (−40.7% at 1000 m, and in the volume of ocean suboxic zones (+12.5%. A sensitivity analysis removing an acidification feedback on calcification finds that change in this process significantly impacts benthic communities, suggesting that a~better understanding of the OA-sensitivity of calcifying organisms, and their role in ballasting sinking organic carbon, may significantly improve forecasting of these ecosystems. For all processes, there is geographical variability in change – for instance, productivity declines −21% in the Atlantic and increases +59% in

Impacts of ocean acidification on marine organisms: quantifying sensitivities and interaction with warming.

Science.gov (United States)

Kroeker, Kristy J; Kordas, Rebecca L; Crim, Ryan; Hendriks, Iris E; Ramajo, Laura; Singh, Gerald S; Duarte, Carlos M; Gattuso, Jean-Pierre

2013-06-01

Ocean acidification represents a threat to marine species worldwide, and forecasting the ecological impacts of acidification is a high priority for science, management, and policy. As research on the topic expands at an exponential rate, a comprehensive understanding of the variability in organisms' responses and corresponding levels of certainty is necessary to forecast the ecological effects. Here, we perform the most comprehensive meta-analysis to date by synthesizing the results of 228 studies examining biological responses to ocean acidification. The results reveal decreased survival, calcification, growth, development and abundance in response to acidification when the broad range of marine organisms is pooled together. However, the magnitude of these responses varies among taxonomic groups, suggesting there is some predictable trait-based variation in sensitivity, despite the investigation of approximately 100 new species in recent research. The results also reveal an enhanced sensitivity of mollusk larvae, but suggest that an enhanced sensitivity of early life history stages is not universal across all taxonomic groups. In addition, the variability in species' responses is enhanced when they are exposed to acidification in multi-species assemblages, suggesting that it is important to consider indirect effects and exercise caution when forecasting abundance patterns from single-species laboratory experiments. Furthermore, the results suggest that other factors, such as nutritional status or source population, could cause substantial variation in organisms' responses. Last, the results highlight a trend towards enhanced sensitivity to acidification when taxa are concurrently exposed to elevated seawater temperature. © 2013 Blackwell Publishing Ltd.

Anticipating ocean acidification's economic consequences for commercial fisheries

International Nuclear Information System (INIS)

Cooley, Sarah R; Doney, Scott C

2009-01-01

Ocean acidification, a consequence of rising anthropogenic CO 2 emissions, is poised to change marine ecosystems profoundly by increasing dissolved CO 2 and decreasing ocean pH, carbonate ion concentration, and calcium carbonate mineral saturation state worldwide. These conditions hinder growth of calcium carbonate shells and skeletons by many marine plants and animals. The first direct impact on humans may be through declining harvests and fishery revenues from shellfish, their predators, and coral reef habitats. In a case study of US commercial fishery revenues, we begin to constrain the economic effects of ocean acidification over the next 50 years using atmospheric CO 2 trajectories and laboratory studies of its effects, focusing especially on mollusks. In 2007, the $3.8 billion US annual domestic ex-vessel commercial harvest ultimately contributed $34 billion to the US gross national product. Mollusks contributed 19%, or $748 million, of the ex-vessel revenues that year. Substantial revenue declines, job losses, and indirect economic costs may occur if ocean acidification broadly damages marine habitats, alters marine resource availability, and disrupts other ecosystem services. We review the implications for marine resource management and propose possible adaptation strategies designed to support fisheries and marine-resource-dependent communities, many of which already possess little economic resilience.

Ocean warming and acidification synergistically increase coral mortality

Science.gov (United States)

Prada, F.; Caroselli, E.; Mengoli, S.; Brizi, L.; Fantazzini, P.; Capaccioni, B.; Pasquini, L.; Fabricius, K. E.; Dubinsky, Z.; Falini, G.; Goffredo, S.

2017-01-01

Organisms that accumulate calcium carbonate structures are particularly vulnerable to ocean warming (OW) and ocean acidification (OA), potentially reducing the socioeconomic benefits of ecosystems reliant on these taxa. Since rising atmospheric CO2 is responsible for global warming and increasing ocean acidity, to correctly predict how OW and OA will affect marine organisms, their possible interactive effects must be assessed. Here we investigate, in the field, the combined temperature (range: 16-26 °C) and acidification (range: pHTS 8.1-7.4) effects on mortality and growth of Mediterranean coral species transplanted, in different seasonal periods, along a natural pH gradient generated by a CO2 vent. We show a synergistic adverse effect on mortality rates (up to 60%), for solitary and colonial, symbiotic and asymbiotic corals, suggesting that high seawater temperatures may have increased their metabolic rates which, in conjunction with decreasing pH, could have led to rapid deterioration of cellular processes and performance. The net calcification rate of the symbiotic species was not affected by decreasing pH, regardless of temperature, while in the two asymbiotic species it was negatively affected by increasing acidification and temperature, suggesting that symbiotic corals may be more tolerant to increasing warming and acidifying conditions compared to asymbiotic ones.

Juvenile Pen Shells (Pinna nobilis) Tolerate Acidification but Are Vulnerable to Warming

KAUST Repository

Basso, Lorena

2015-02-25

In the course of this century, rising anthropogenic CO2 emissions will likely cause a decrease in ocean pH, know as ocean acidification, together with an increase of water temperature. Only in the last years, studies have focused on synergetic effects of both stressors on marine invertebrates, particularly on early life stages considered more vulnerable. Disparate responses of their singular and combined effects were reported, highlighting the importance of extending the studies to different species and populations of marine invertebrates. Here, we observed the response of important parameters such as growth, mortality and oxygen consumption of juvenile pen shell Pinna nobilis at supplied pCO2 gas levels of 400 ppm (ambient) and 1000 ppm and at three temperatures (20, 23 and 26 °C) during 36 days. To our knowledge, this is the first study on ocean acidification and temperature effects on juveniles of this species. We show that the two stressors play roles at distinct levels, with pCO2 influencing growth and partially mortality, and temperature increasing mortality rates and oxygen consumption strongly. Therefore, juveniles of P. nobilis are more likely affected by increasing temperature than the pCO2 levels expected by the end of the twenty-first century.

Enhanced weathering strategies for stabilizing climate and averting ocean acidification

Science.gov (United States)

Taylor, Lyla L.; Quirk, Joe; Thorley, Rachel M. S.; Kharecha, Pushker A.; Hansen, James; Ridgwell, Andy; Lomas, Mark R.; Banwart, Steve A.; Beerling, David J.

2016-04-01

Chemical breakdown of rocks, weathering, is an important but very slow part of the carbon cycle that ultimately leads to CO2 being locked up in carbonates on the ocean floor. Artificial acceleration of this carbon sink via distribution of pulverized silicate rocks across terrestrial landscapes may help offset anthropogenic CO2 emissions. We show that idealized enhanced weathering scenarios over less than a third of tropical land could cause significant drawdown of atmospheric CO2 and ameliorate ocean acidification by 2100. Global carbon cycle modelling driven by ensemble Representative Concentration Pathway (RCP) projections of twenty-first-century climate change (RCP8.5, business-as-usual; RCP4.5, medium-level mitigation) indicates that enhanced weathering could lower atmospheric CO2 by 30-300 ppm by 2100, depending mainly on silicate rock application rate (1 kg or 5 kg m-2 yr-1) and composition. At the higher application rate, end-of-century ocean acidification is reversed under RCP4.5 and reduced by about two-thirds under RCP8.5. Additionally, surface ocean aragonite saturation state, a key control on coral calcification rates, is maintained above 3.5 throughout the low latitudes, thereby helping maintain the viability of tropical coral reef ecosystems. However, we highlight major issues of cost, social acceptability, and potential unanticipated consequences that will limit utilization and emphasize the need for urgent efforts to phase down fossil fuel emissions.

Enhanced Weathering Strategies for Stabilizing Climate and Averting Ocean Acidification

Science.gov (United States)

Taylor, Lyla L.; Quirk, Joe; Thorley, Rachel M. S.; Kharecha, Pushker A.; Hansen, James; Ridgwell, Andy; Lomas, Mark R.; Banwart, Steve A.; Beerling, David J.

2015-01-01

Chemical breakdown of rocks, weathering, is an important but very slow part of the carbon cycle that ultimately leads to CO2 being locked up in carbonates on the ocean floor. Artificial acceleration of this carbon sink via distribution of pulverized silicate rocks across terrestrial landscapes may help offset anthropogenic CO2 emissions. We show that idealized enhanced weathering scenarios over less than a third of tropical land could cause significant drawdown of atmospheric CO2 and ameliorate ocean acidification by 2100. Global carbon cycle modelling driven by ensemble Representative Concentration Pathway (RCP) projections of twenty-first-century climate change (RCP8.5, business-as-usual; RCP4.5, medium-level mitigation) indicates that enhanced weathering could lower atmospheric CO2 by 30-300 ppm by 2100, depending mainly on silicate rock application rate (1 kg or 5 kg m(exp -2) yr (exp -1)) and composition. At the higher application rate, end-of-century ocean acidification is reversed under RCP4.5 and reduced by about two-thirds under RCP8.5. Additionally, surface ocean aragonite saturation state, a key control on coral calcification rates, is maintained above 3.5 throughout the low latitudes, thereby helping maintain the viability of tropical coral reef ecosystems. However, we highlight major issues of cost, social acceptability, and potential unanticipated consequences that will limit utilization and emphasize the need for urgent efforts to phase down fossil fuel emissions.

How much acidification has occurred in Adirondack region lakes (New York, USA) since preindustrial times

International Nuclear Information System (INIS)

Cumming, B.F.; Smol, J.P.; Kingston, J.C.; Charles, D.F.; Birks, H.J.B.

1992-01-01

Preindustrial and present-day lake water pH, acid neutralizing capacity (ANC), total monomeric aluminum Al(sub m), and dissolved organic carbon (DOC) were inferred from the species composition of diatom and chrysophyte microfossils in the tops (present-day inferences) and bottoms (pre-1850 inferences) of sediment cores collected from a statistically selected set of Adirondack lakes. Results from the study lakes were extrapolated to a predefined target population of 675 low-alkalinity Adirondack region lakes. Estimates of preindustrial to present-day changes in lake water chemistry show that approximately 25-35% of the target population has acidified. The magnitude of acidification was greatest in the low-alkalinity lakes of the southwestern Adirondacks, an area with little geological ability to neutralize acidic deposition and receives the highest annual average rainfall in the region. The authors estimate that approximately 80% of the target population lakes with present-day measured pH = or < 5.2 and 30-45% of lakes with pH between 5.2 and 6.0 have undergone large declines in pH and ANC, and concomitant increases in Al(sub m). Estimated changes in (DOC) were small and show no consistent pattern in the acidified lakes. The study provides the first statistically based regional evaluation of the extent of lake acidification in the Adirondacks

Effect factors for terrestrial acidification in Brazil

DEFF Research Database (Denmark)

Crespo Mendes, Natalia; Laurent, Alexis; Hauschild, Michael Zwicky

conditions, which is an essential approach considering countries like Brazil, with high biodiversity. Previous studies have assessed the impacts of terrestrial acidification from the estimations of the potential losses of vascular plants species richness as a result of exposure to acidifying substances...... for 13 biomes, with 2409 species addressed for whole world. In this context this work aims to provide spatially-differentiated effect factors (EF) for terrestrial acidification in Brazil and support the development of spatially-differentiated characterization factors for Brazil. In order to maintain...... in Brazil, represented by 33167 species, indicating that this is a comprehensive study. Maps of soil pH in Brazil were extracted at 1-km resolution and pH values were extracted for the depth range of 0-30cm. For each ecoregion, species richness was plotted against soil pH and the exposure-response curves...

Desert Beetle-Inspired Superwettable Patterned Surfaces for Water Harvesting.

Science.gov (United States)

Yu, Zhenwei; Yun, Frank F; Wang, Yanqin; Yao, Li; Dou, Shixue; Liu, Kesong; Jiang, Lei; Wang, Xiaolin

2017-09-01

With the impacts of climate change and impending crisis of clean drinking water, designing functional materials for water harvesting from fog with large water capacity has received much attention in recent years. Nature has evolved different strategies for surviving dry, arid, and xeric conditions. Nature is a school for human beings. In this contribution, inspired by the Stenocara beetle, superhydrophilic/superhydrophobic patterned surfaces are fabricated on the silica poly(dimethylsiloxane) (PDMS)-coated superhydrophobic surfaces using a pulsed laser deposition approach with masks. The resultant samples with patterned wettability demonstrate water-harvesting efficiency in comparison with the silica PDMS-coated superhydrophobic surface and the Pt nanoparticles-coated superhydrophilic surface. The maximum water-harvesting efficiency can reach about 5.3 g cm -2 h -1 . Both the size and the percentage of the Pt-coated superhydrophilic square regions on the patterned surface affect the condensation and coalescence of the water droplet, as well as the final water-harvesting efficiency. The present water-harvesting strategy should provide an avenue to alleviate the water crisis facing mankind in certain arid regions of the world. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Ocean Acidification: a review of the current status of research and institutional developments

NARCIS (Netherlands)

Beek, van I.J.M.; Dedert, M.

2012-01-01

Ocean acidification is defined as the change in ocean chemistry driven by the oceanic uptake of chemical inputs to the atmosphere, including carbon, nitrogen and sulphur compounds. Ocean acidification is also referred to as ‘the other CO2 problem’ of anthropogenic carbon dioxide (CO2) emissions

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

Science.gov (United States)

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 (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.

Study on combined effects of acidification and sonication on selected quality attributes of carrot juice during storage

International Nuclear Information System (INIS)

Jabbar, S.; Hu, B.; Ali, S.

2014-01-01

This study evaluated the combined effects of acid blanching and sonication treatments on selected quality parameters of carrot juice stored at 4 degree C for 18 days. Carrots were blanched in acidified water (40g/L citric acid) at 100 degree C for 4 min and the juice was then extracted. Sonication of the juice was done at an amplitude level of 70% and a frequency of 20 kHz for 2 min at 15 degree C, keeping the pulse duration of 5 Sec on and 5 Sec off. As results, the combined treatment of acidification and sonication of carrot juice showed a significant decrease in pH and increase (P < 0.05) in acidity which remained stable during storage period. No significant changes were observed in Brix. Color values (L, a, b) and non enzymatic browning (NEB) influenced significantly in acidified and sonicated carrot juice during storage period. Maximum stability of total phenol, total antioxidant capacity, cloud value and ascorbic acid were also observed in the combined treatment of acidification and sonication. The findings of this study indicated that the combined treatments of acidification and sonication may successfully be utilized for the production of high quality carrot juice with improved stability of total phenol, total antioxidant capacity, cloud value and ascorbic acid during 18 days of storage. (author)

chemical and microbiological assessment of surface water samples

African Journals Online (AJOL)

PROF EKWUEME

concentrations and bacteriological content. Evaluation of the results ... and Aninri local government areas of Enugu state. Surface water ... surface water bodies are prone to impacts from ... Coal Measures (Akamigbo, 1987). The geologic map ...

Effects of ocean acidification on calcification of symbiont-bearing reef foraminifers

Science.gov (United States)

Fujita, K.; Hikami, M.; Suzuki, A.; Kuroyanagi, A.; Sakai, K.; Kawahata, H.; Nojiri, Y.

2011-08-01

Ocean acidification (decreases in carbonate ion concentration and pH) in response to rising atmospheric pCO2 is generally expected to reduce rates of calcification by reef calcifying organisms, with potentially severe implications for coral reef ecosystems. Large, algal symbiont-bearing benthic foraminifers, which are important primary and carbonate producers in coral reefs, produce high-Mg calcite shells, whose solubility can exceed that of aragonite produced by corals, making them the "first responder" in coral reefs to the decreasing carbonate saturation state of seawater. Here we report results of culture experiments performed to assess the effects of ongoing ocean acidification on the calcification of symbiont-bearing reef foraminifers using a high-precision pCO2 control system. Living clone individuals of three foraminiferal species (Baculogypsina sphaerulata, Calcarina gaudichaudii, and Amphisorus hemprichii) were subjected to seawater at five pCO2 levels from 260 to 970 μatm. Cultured individuals were maintained for about 12 weeks in an indoor flow-through system under constant water temperature, light intensity, and photoperiod. After the experiments, the shell diameter and weight of each cultured specimen were measured. Net calcification of B. sphaerulata and C. gaudichaudii, which secrete a hyaline shell and host diatom symbionts, increased under intermediate levels of pCO2 (580 and/or 770 μatm) and decreased at a higher pCO2 level (970 μatm). Net calcification of A. hemprichii, which secretes a porcelaneous shell and hosts dinoflagellate symbionts, tended to decrease at elevated pCO2. Observed different responses between hyaline and porcelaneous species are possibly caused by the relative importance of elevated pCO2, which induces CO2 fertilization effects by algal symbionts, versus associated changes in seawater carbonate chemistry, which decreases a carbonate concentration. Our findings suggest that ongoing ocean acidification might favor symbiont

A deformable surface model for real-time water drop animation.

Science.gov (United States)

Zhang, Yizhong; Wang, Huamin; Wang, Shuai; Tong, Yiying; Zhou, Kun

2012-08-01

A water drop behaves differently from a large water body because of its strong viscosity and surface tension under the small scale. Surface tension causes the motion of a water drop to be largely determined by its boundary surface. Meanwhile, viscosity makes the interior of a water drop less relevant to its motion, as the smooth velocity field can be well approximated by an interpolation of the velocity on the boundary. Consequently, we propose a fast deformable surface model to realistically animate water drops and their flowing behaviors on solid surfaces. Our system efficiently simulates water drop motions in a Lagrangian fashion, by reducing 3D fluid dynamics over the whole liquid volume to a deformable surface model. In each time step, the model uses an implicit mean curvature flow operator to produce surface tension effects, a contact angle operator to change droplet shapes on solid surfaces, and a set of mesh connectivity updates to handle topological changes and improve mesh quality over time. Our numerical experiments demonstrate a variety of physically plausible water drop phenomena at a real-time rate, including capillary waves when water drops collide, pinch-off of water jets, and droplets flowing over solid materials. The whole system performs orders-of-magnitude faster than existing simulation approaches that generate comparable water drop effects.

Impact of ocean acidification and warming on the productivity of a rock pool community.

Science.gov (United States)

Legrand, Erwann; Riera, Pascal; Bohner, Olivier; Coudret, Jérôme; Schlicklin, Ferdinand; Derrien, Marie; Martin, Sophie

2018-05-01

This study examined experimentally the combined effect of ocean acidification and warming on the productivity of rock pool multi-specific assemblages, composed of coralline algae, fleshy algae, and grazers. Natural rock pool communities experience high environmental fluctuations. This may confer physiological advantage to rock pool communities when facing predicted acidification and warming. The effect of ocean acidification and warming have been assessed at both individual and assemblage level to examine the importance of species interactions in the response of assemblages. We hypothesized that rock pool assemblages have physiological advantage when facing predicted ocean acidification and warming. Species exhibited species-specific responses to increased temperature and pCO 2 . Increased temperature and pCO 2 have no effect on assemblage photosynthesis, which was mostly influenced by fleshy algal primary production. The response of coralline algae to ocean acidification and warming depended on the season, which evidenced the importance of physiological adaptations to their environment in their response to climate change. We suggest that rock pool assemblages are relatively robust to changes in temperature and pCO 2 , in terms of primary production. Copyright © 2018 Elsevier Ltd. All rights reserved.

Ocean acidification increases cadmium accumulation in marine bivalves: a potential threat to seafood safety.

Science.gov (United States)

Shi, Wei; Zhao, Xinguo; Han, Yu; Che, Zhumei; Chai, Xueliang; Liu, Guangxu

2016-01-21

To date, the effects of ocean acidification on toxic metals accumulation and the underlying molecular mechanism remains unknown in marine bivalve species. In the present study, the effects of the realistic future ocean pCO2 levels on the cadmium (Cd) accumulation in the gills, mantle and adductor muscles of three bivalve species, Mytilus edulis, Tegillarca granosa, and Meretrix meretrix, were investigated. The results obtained suggested that all species tested accumulated significantly higher Cd (p ocean acidification-induced increase in Cd accumulation may have occurred due to (i) the ocean acidification increased the concentration of Cd and the Cd(2+)/Ca(2+) in the seawater, which in turn increased the Cd influx through Ca channel; (ii) the acidified seawater may have brought about epithelia damage, resulting in easier Cd penetration; and (iii) ocean acidification hampered Cd exclusion.

25 years acidification monitoring in Bavaria. Trends and developments; 25 Jahre Versauerungsmonitoring in Bayern. Trends und Entwicklungen

Energy Technology Data Exchange (ETDEWEB)

Scheel, Thorsten

2015-07-15

In Bavaria, the development of the atmospheric caused acidification within all relevant environmental compartments (soil, water, air) is monitored by an intensive monitoring for more than 25 years. This report covers the trends and developments of chemical and biological indicators of flowing waters, groundwater and lakes are summarized evaluated and displayed. [German] In Bayern wird seit mehr als 25 Jahren die Entwicklung der atmosphaerisch bedingten Versauerung innerhalb aller betroffenen Umweltkompartimente (Boden, Wasser, Luft) durch ein intensives Monitoring ueberwacht. In diesem Bericht sind die Trends und Entwicklungen chemischer und biologischer Indikatoren der Fliessgewaesser, Grundwaesser und Seen zusammenfassend ausgewertet und dargestellt.

Wetlands inform how climate extremes influence surface water expansion and contraction

Science.gov (United States)

Vanderhoof, Melanie K.; Lane, Charles R.; McManus, Michael G.; Alexander, Laurie C.; Christensen, Jay R.

2018-03-01

Effective monitoring and prediction of flood and drought events requires an improved understanding of how and why surface water expansion and contraction in response to climate varies across space. This paper sought to (1) quantify how interannual patterns of surface water expansion and contraction vary spatially across the Prairie Pothole Region (PPR) and adjacent Northern Prairie (NP) in the United States, and (2) explore how landscape characteristics influence the relationship between climate inputs and surface water dynamics. Due to differences in glacial history, the PPR and NP show distinct patterns in regards to drainage development and wetland density, together providing a diversity of conditions to examine surface water dynamics. We used Landsat imagery to characterize variability in surface water extent across 11 Landsat path/rows representing the PPR and NP (images spanned 1985-2015). The PPR not only experienced a 2.6-fold greater surface water extent under median conditions relative to the NP, but also showed a 3.4-fold greater change in surface water extent between drought and deluge conditions. The relationship between surface water extent and accumulated water availability (precipitation minus potential evapotranspiration) was quantified per watershed and statistically related to variables representing hydrology-related landscape characteristics (e.g., infiltration capacity, surface storage capacity, stream density). To investigate the influence stream connectivity has on the rate at which surface water leaves a given location, we modeled stream-connected and stream-disconnected surface water separately. Stream-connected surface water showed a greater expansion with wetter climatic conditions in landscapes with greater total wetland area, but lower total wetland density. Disconnected surface water showed a greater expansion with wetter climatic conditions in landscapes with higher wetland density, lower infiltration and less anthropogenic drainage

Wetlands inform how climate extremes influence surface water expansion and contraction

Science.gov (United States)

Vanderhoof, Melanie; Lane, Charles R.; McManus, Michael L.; Alexander, Laurie C.; Christensen, Jay R.

2018-01-01

Effective monitoring and prediction of flood and drought events requires an improved understanding of how and why surface water expansion and contraction in response to climate varies across space. This paper sought to (1) quantify how interannual patterns of surface water expansion and contraction vary spatially across the Prairie Pothole Region (PPR) and adjacent Northern Prairie (NP) in the United States, and (2) explore how landscape characteristics influence the relationship between climate inputs and surface water dynamics. Due to differences in glacial history, the PPR and NP show distinct patterns in regards to drainage development and wetland density, together providing a diversity of conditions to examine surface water dynamics. We used Landsat imagery to characterize variability in surface water extent across 11 Landsat path/rows representing the PPR and NP (images spanned 1985–2015). The PPR not only experienced a 2.6-fold greater surface water extent under median conditions relative to the NP, but also showed a 3.4-fold greater change in surface water extent between drought and deluge conditions. The relationship between surface water extent and accumulated water availability (precipitation minus potential evapotranspiration) was quantified per watershed and statistically related to variables representing hydrology-related landscape characteristics (e.g., infiltration capacity, surface storage capacity, stream density). To investigate the influence stream connectivity has on the rate at which surface water leaves a given location, we modeled stream-connected and stream-disconnected surface water separately. Stream-connected surface water showed a greater expansion with wetter climatic conditions in landscapes with greater total wetland area, but lower total wetland density. Disconnected surface water showed a greater expansion with wetter climatic conditions in landscapes with higher wetland density, lower infiltration and less anthropogenic

Wetlands inform how climate extremes influence surface water expansion and contraction

Directory of Open Access Journals (Sweden)

M. K. Vanderhoof

2018-03-01

Full Text Available Effective monitoring and prediction of flood and drought events requires an improved understanding of how and why surface water expansion and contraction in response to climate varies across space. This paper sought to (1 quantify how interannual patterns of surface water expansion and contraction vary spatially across the Prairie Pothole Region (PPR and adjacent Northern Prairie (NP in the United States, and (2 explore how landscape characteristics influence the relationship between climate inputs and surface water dynamics. Due to differences in glacial history, the PPR and NP show distinct patterns in regards to drainage development and wetland density, together providing a diversity of conditions to examine surface water dynamics. We used Landsat imagery to characterize variability in surface water extent across 11 Landsat path/rows representing the PPR and NP (images spanned 1985–2015. The PPR not only experienced a 2.6-fold greater surface water extent under median conditions relative to the NP, but also showed a 3.4-fold greater change in surface water extent between drought and deluge conditions. The relationship between surface water extent and accumulated water availability (precipitation minus potential evapotranspiration was quantified per watershed and statistically related to variables representing hydrology-related landscape characteristics (e.g., infiltration capacity, surface storage capacity, stream density. To investigate the influence stream connectivity has on the rate at which surface water leaves a given location, we modeled stream-connected and stream-disconnected surface water separately. Stream-connected surface water showed a greater expansion with wetter climatic conditions in landscapes with greater total wetland area, but lower total wetland density. Disconnected surface water showed a greater expansion with wetter climatic conditions in landscapes with higher wetland density, lower infiltration and less

Potentially hazardous substances in surface waters. II. Cholinesterase inhibitors in Dutch surface waters

NARCIS (Netherlands)

Greve, P.A.; Freudenthal, J.; Wit, S.L.

1972-01-01

Several analytical methods were employed to determine the concentrations of cholinesterase inhibitors in several Dutch surface waters. An Auto-Analyzer method was used for screening purposes; thin-layer chromatography and gas-liquid chromatography-mass spectrometry were used for identification and

Experimental acidification of two biogeochemically-distinct neotropical streams: Buffering mechanisms and macroinvertebrate drift

International Nuclear Information System (INIS)

Ardón, Marcelo; Duff, John H.; Ramírez, Alonso; Small, Gaston E.; Jackman, Alan P.; Triska, Frank J.; Pringle, Catherine M.

2013-01-01

Research into the buffering mechanisms and ecological consequences of acidification in tropical streams is lacking. We have documented seasonal and episodic acidification events in streams draining La Selva Biological Station, Costa Rica. Across this forested landscape, the severity in seasonal and episodic acidification events varies due to interbasin groundwater flow (IGF). Streams that receive IGF have higher concentrations of solutes and more stable pH (∼ 6) than streams that do not receive IGF (pH ∼ 5). To examine the buffering capacity and vulnerability of macroinvertebrates to short-term acidification events, we added hydrochloric acid to acidify a low-solute, poorly buffered (without IGF) and a high-solute, well buffered stream (with IGF). We hypothesized that: 1) protonation of bicarbonate (HCO 3 − ) would neutralize most of the acid added in the high-solute stream, while base cation release from the sediments would be the most important buffering mechanism in the low-solute stream; 2) pH declines would mobilize inorganic aluminum (Ali) from sediments in both streams; and 3) pH declines would increase macroinvertebrate drift in both streams. We found that the high-solute stream neutralized 745 μeq/L (96% of the acid added), while the solute poor stream only neutralized 27.4 μeq/L (40%). Protonation of HCO 3 − was an important buffering mechanism in both streams. Base cation, Fe 2+ , and Ali release from sediments and protonation of organic acids also provided buffering in the low-solute stream. We measured low concentrations of Ali release in both streams (2-9 μeq/L) in response to acidification, but the low-solute stream released double the amount Ali per 100 μeq of acid added than the high solute stream. Macroinvertebrate drift increased in both streams in response to acidification and was dominated by Ephemeroptera and Chironomidae. Our results elucidate the different buffering mechanisms in tropical streams and suggest that low

Cooperativity in Surface Bonding and Hydrogen Bonding of Water and Hydroxyl at Metal Surfaces

DEFF Research Database (Denmark)

Schiros, T.; Ogasawara, H.; Naslund, L. A.

2010-01-01

of the mixed phase at metal surfaces. The surface bonding can be considered to be similar to accepting a hydrogen bond, and we can thereby apply general cooperativity rules developed for hydrogen-bonded systems. This provides a simple understanding of why water molecules become more strongly bonded...... to the surface upon hydrogen bonding to OH and why the OH surface bonding is instead weakened through hydrogen bonding to water. We extend the application of this simple model to other observed cooperativity effects for pure water adsorption systems and H3O+ on metal surfaces.......We examine the balance of surface bonding and hydrogen bonding in the mixed OH + H2O overlayer on Pt(111), Cu(111), and Cu(110) via density functional theory calculations. We find that there is a cooperativity effect between surface bonding and hydrogen bonding that underlies the stability...

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

Science.gov (United States)

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.

Surface wastewater in Samara and their impact on water basins as water supply sources

Science.gov (United States)

Strelkov, Alexander; Shuvalov, Mikhail; Gridneva, Marina

2017-10-01

The paper gives an overview of surface wastewater outlets in Samara through the rainwater sewer system into the Saratov water reservoir and the Samara river. The rainwater sewer system in Samara is designed and executed according to a separate scheme, except for the old part of the city, where surface run-off is dumped into the sewer system through siphoned drain. The rainwater system disposes of surface, drainage, industrial clean-contamined waters, emergency and technology discharges from the city’s heat supply and water supply systems. The effluent discharge is carried out by means of separate wastewater outlets into ravines or directly into the Samara river and the Saratov water reservoir without cleaning. The effluent discharge is carried out through the rainwater sewer system with 17 wastewater outlets into the Saratov water reservoir. In the Samara river, surface runoff drainage and clean-contamined water of industrial enterprises is carried out through 14 wastewater outlets. This study emphasizes the demand to arrange effluent discharge and construction of sewage treatment plants to prevent contamination of water objects by surface run-off from residential areas and industrial territories.

Escape jumping by three age-classes of water striders from smooth, wavy and bubbling water surfaces.

Science.gov (United States)

Ortega-Jimenez, Victor Manuel; von Rabenau, Lisa; Dudley, Robert

2017-08-01

Surface roughness is a ubiquitous phenomenon in both oceanic and terrestrial waters. For insects that live at the air-water interface, such as water striders, non-linear and multi-scale perturbations produce dynamic surface deformations which may impair locomotion. We studied escape jumps of adults, juveniles and first-instar larvae of the water strider Aquarius remigis on smooth, wave-dominated and bubble-dominated water surfaces. Effects of substrate on takeoff jumps were substantial, with significant reductions in takeoff angles, peak translational speeds, attained heights and power expenditure on more perturbed water surfaces. Age effects were similarly pronounced, with the first-instar larvae experiencing the greatest degradation in performance; age-by-treatment effects were also significant for many kinematic variables. Although commonplace in nature, perturbed water surfaces thus have significant and age-dependent effects on water strider locomotion, and on behavior more generally of surface-dwelling insects. © 2017. Published by The Company of Biologists Ltd.

Partitioning of water between surface and mantle on terrestrial exoplanets: effect of surface-mantle water exchange parameterizations on ocean depth

Science.gov (United States)

Komacek, T. D.; Abbot, D. S.

2016-12-01

Terrestrial exoplanets in the canonical habitable zone may have a variety of initial water fractions due to their volatile delivery rate via planetesimals. If the total planetary water complement is high, the entire surface may be covered in water, forming a "waterworld". The habitable zone for waterworlds is likely smaller than that for planets with partial land coverage because waterworlds lack the stabilizing silicate-weathering feedback. On a planet with active tectonics, competing mechanisms act to regulate the abundance of water on the surface by determining the partitioning of water between interior and surface. We have explored how the incorporation of different mechanisms for the outgassing and regassing of water changes the volatile evolution of a planet. Specifically, we have examined three models for volatile cycling: a model with degassing and regassing both determined by the seafloor pressure, one with mantle temperature-dependent degassing and regassing rates, and a hybrid model that has the degassing rate driven by seafloor pressure and the regassing rate determined by the mantle temperature. We find that the volatile cycling in all three of these scenarios reaches a steady-state after a few billion years. Using these steady-states, we can make predictions from each model for how much water is needed to flood the surface and make a waterworld. We find that if volatile cycling is either solely temperature-dependent or pressure-dependent, exoplanets require a high abundance (more than 0.3% by mass) of water to have fully inundated surfaces. This is because the waterworld boundary for these models is regulated by how much water can be stuffed into the mantle. However, if degassing is more dependent on the seafloor pressure and regassing mainly dependent on mantle temperature, super-Earth mass planets with a total water fraction similar to that of the Earth (approximately 0.05% by mass) can become waterworlds. As a result, further understanding of the

A GPU-based mipmapping method for water surface visualization

Science.gov (United States)

Li, Hua; Quan, Wei; Xu, Chao; Wu, Yan

2018-03-01

Visualization of water surface is a hot topic in computer graphics. In this paper, we presented a fast method to generate wide range of water surface with good image quality both near and far from the viewpoint. This method utilized uniform mesh and Fractal Perlin noise to model water surface. Mipmapping technology was enforced to the surface textures, which adjust the resolution with respect to the distance from the viewpoint and reduce the computing cost. Lighting effect was computed based on shadow mapping technology, Snell's law and Fresnel term. The render pipeline utilizes a CPU-GPU shared memory structure, which improves the rendering efficiency. Experiment results show that our approach visualizes water surface with good image quality at real-time frame rates performance.

Hypoxia and acidification in ocean ecosystems: coupled dynamics and effects on marine life.

Science.gov (United States)

Gobler, Christopher J; Baumann, Hannes

2016-05-01

There is increasing recognition that low dissolved oxygen (DO) and low pH conditions co-occur in many coastal and open ocean environments. Within temperate ecosystems, these conditions not only develop seasonally as temperatures rise and metabolic rates accelerate, but can also display strong diurnal variability, especially in shallow systems where photosynthetic rates ameliorate hypoxia and acidification by day. Despite the widespread, global co-occurrence of low pH and low DO and the likelihood that these conditions may negatively impact marine life, very few studies have actually assessed the extent to which the combination of both stressors elicits additive, synergistic or antagonistic effects in marine organisms. We review the evidence from published factorial experiments that used static and/or fluctuating pH and DO levels to examine different traits (e.g. survival, growth, metabolism), life stages and species across a broad taxonomic spectrum. Additive negative effects of combined low pH and low DO appear to be most common; however, synergistic negative effects have also been observed. Neither the occurrence nor the strength of these synergistic impacts is currently predictable, and therefore, the true threat of concurrent acidification and hypoxia to marine food webs and fisheries is still not fully understood. Addressing this knowledge gap will require an expansion of multi-stressor approaches in experimental and field studies, and the development of a predictive framework. In consideration of marine policy, we note that DO criteria in coastal waters have been developed without consideration of concurrent pH levels. Given the persistence of concurrent low pH-low DO conditions in estuaries and the increased mortality experienced by fish and bivalves under concurrent acidification and hypoxia compared with hypoxia alone, we conclude that such DO criteria may leave coastal fisheries more vulnerable to population reductions than previously anticipated. © 2016

Recovery from episodic acidification delayed by drought and high sea salt deposition

Directory of Open Access Journals (Sweden)

H. Laudon

2008-03-01

Full Text Available For the prediction of episodic acidification large uncertainties are connected to climatic variability and its effect on drought conditions and sea-salt episodes. In this study data on 342 hydrological episodes in 25 Swedish streams, sampled over 10 years, have been analyzed using a recently developed episode model. The results demonstrate that drought is the most important factor modulating the magnitude of the anthropogenic influence on pH and ANC during episodes. These modulating effects are especially pronounced in southern and central Sweden, where the historically high acid deposition has resulted in significant S pools in catchment soils. The results also suggest that the effects of episodic acidification are becoming less severe in many streams, but this amelioration is less clear in coastal streams subject to high levels of sea-salt deposition. Concurrently with the amelioration of the effects of episodic acidification, regional climate models predict that temperatures will increase in Sweden during the coming decades, accompanied by reductions in summer precipitation and more frequent storms during fall and winter in large areas of the country. If these predictions are realized delays in streams' recovery from episodic acidification events can be expected.

Ocean Acidification Scientific Data Stewardship: An approach for end-to-end data management and integration

Science.gov (United States)

Arzayus, K. M.; Garcia, H. E.; Jiang, L.; Michael, P.

2012-12-01

As the designated Federal permanent oceanographic data center in the United States, NOAA's National Oceanographic Data Center (NODC) has been providing scientific stewardship for national and international marine environmental and ecosystem data for over 50 years. NODC is supporting NOAA's Ocean Acidification Program and the science community by providing end-to-end scientific data management of ocean acidification (OA) data, dedicated online data discovery, and user-friendly access to a diverse range of historical and modern OA and other chemical, physical, and biological oceanographic data. This effort is being catalyzed by the NOAA Ocean Acidification Program, but the intended reach is for the broader scientific ocean acidification community. The first three years of the project will be focused on infrastructure building. A complete ocean acidification data content standard is being developed to ensure that a full spectrum of ocean acidification data and metadata can be stored and utilized for optimal data discovery and access in usable data formats. We plan to develop a data access interface capable of allowing users to constrain their search based on real-time and delayed mode measured variables, scientific data quality, their observation types, the temporal coverage, methods, instruments, standards, collecting institutions, and the spatial coverage. In addition, NODC seeks to utilize the existing suite of international standards (including ISO 19115-2 and CF-compliant netCDF) to help our data producers use those standards for their data, and help our data consumers make use of the well-standardized metadata-rich data sets. These tools will be available through our NODC Ocean Acidification Scientific Data Stewardship (OADS) web page at http://www.nodc.noaa.gov/oceanacidification. NODC also has a goal to provide each archived dataset with a unique ID, to ensure a means of providing credit to the data provider. Working with partner institutions, such as the

Water surface coverage effects on reactivity of plasma oxidized Ti films

International Nuclear Information System (INIS)

Pranevicius, L.; Pranevicius, L.L.; Vilkinis, P.; Baltaragis, S.; Gedvilas, K.

2014-01-01

Highlights: • The reactivity of Ti films immersed in water vapor plasma depends on the surface water coverage. • The adsorbed water monolayers are disintegrated into atomic constituents on the hydrophilic TiO 2 under plasma radiation. • The TiO 2 surface covered by water multilayer loses its ability to split adsorbed water molecules under plasma radiation. - Abstract: The behavior of the adsorbed water on the surface of thin sputter deposited Ti films maintained at room temperature was investigated in dependence on the thickness of the resulting adsorbed water layer, controllably injecting water vapor into plasma. The surface morphology and microstructure were used to characterize the surfaces of plasma treated titanium films. Presented experimental results showed that titanium films immersed in water vapor plasma at pressure of 10–100 Pa promoted the photocatalytic activity of overall water splitting. The surfaces of plasma oxidized titanium covered by an adsorbed hydroxyl-rich island structure water layer and activated by plasma radiation became highly chemically reactive. As water vapor pressure increased up to 300–500 Pa, the formed water multilayer diminished the water oxidation and, consequently, water splitting efficiency decreased. Analysis of the experimental results gave important insights into the role an adsorbed water layer on surface of titanium exposed to water vapor plasma on its chemical activity and plasma activated electrochemical processes, and elucidated the surface reactions that could lead to the split of water molecules

Surface-Water and Ground-Water Interactions in the Central Everglades, Florida

Science.gov (United States)

Harvey, Judson W.; Newlin, Jessica T.; Krest, James M.; Choi, Jungyill; Nemeth, Eric A.; Krupa, Steven L.

2004-01-01

Recharge and discharge are hydrological processes that cause Everglades surface water to be exchanged for subsurface water in the peat soil and the underlying sand and limestone aquifer. These interactions are thought to be important to water budgets, water quality, and ecology in the Everglades. Nonetheless, relatively few studies of surface water and ground water interactions have been conducted in the Everglades, especially in its vast interior areas. This report is a product of a cooperative investigation conducted by the USGS and the South Florida Water Management District (SFWMD) aimed at developing and testing techniques that would provide reliable estimates of recharge and discharge in interior areas of WCA-2A (Water Conservation Area 2A) and several other sites in the central Everglades. The new techniques quantified flow from surface water to the subsurface (recharge) and the opposite (discharge) using (1) Darcy-flux calculations based on measured vertical gradients in hydraulic head and hydraulic conductivity of peat; (2) modeling transport through peat and decay of the naturally occurring isotopes 224Ra and 223Ra (with half-lives of 4 and 11 days, respectively); and (3) modeling transport and decay of naturally occurring and 'bomb-pulse' tritium (half-life of 12.4 years) in ground water. Advantages and disadvantages of each method for quantifying recharge and discharge were compared. In addition, spatial and temporal variability of recharge and discharge were evaluated and controlling factors identified. A final goal was to develop appropriately simplified (that is, time averaged) expressions of the results that will be useful in addressing a broad range of hydrological and ecological problems in the Everglades. Results were compared with existing information about water budgets from the South Florida Water Management Model (SFWMM), a principal tool used by the South Florida Water Management District to plan many of the hydrological aspects of the

Water vapor retrieval over many surface types

Energy Technology Data Exchange (ETDEWEB)

Borel, C.C.; Clodius, W.C.; Johnson, J.

1996-04-01

In this paper we present a study of of the water vapor retrieval for many natural surface types which would be valuable for multi-spectral instruments using the existing Continuum Interpolated Band Ratio (CIBR) for the 940 nm water vapor absorption feature. An atmospheric code (6S) and 562 spectra were used to compute the top of the atmosphere radiance near the 940 nm water vapor absorption feature in steps of 2.5 nm as a function of precipitable water (PW). We derive a novel technique called ``Atmospheric Pre-corrected Differential Absorption`` (APDA) and show that APDA performs better than the CIBR over many surface types.

Thermodynamic properties of water solvating biomolecular surfaces

Science.gov (United States)

Heyden, Matthias

Changes in the potential energy and entropy of water molecules hydrating biomolecular interfaces play a significant role for biomolecular solubility and association. Free energy perturbation and thermodynamic integration methods allow calculations of free energy differences between two states from simulations. However, these methods are computationally demanding and do not provide insights into individual thermodynamic contributions, i.e. changes in the solvent energy or entropy. Here, we employ methods to spatially resolve distributions of hydration water thermodynamic properties in the vicinity of biomolecular surfaces. This allows direct insights into thermodynamic signatures of the hydration of hydrophobic and hydrophilic solvent accessible sites of proteins and small molecules and comparisons to ideal model surfaces. We correlate dynamic properties of hydration water molecules, i.e. translational and rotational mobility, to their thermodynamics. The latter can be used as a guide to extract thermodynamic information from experimental measurements of site-resolved water dynamics. Further, we study energy-entropy compensations of water at different hydration sites of biomolecular surfaces. This work is supported by the Cluster of Excellence RESOLV (EXC 1069) funded by the Deutsche Forschungsgemeinschaft.

Nanofiltration in Transforming Surface Water into Healthy Water: Comparison with Reverse Osmosis

Directory of Open Access Journals (Sweden)

L. D. Naidu

2015-01-01

Full Text Available The natural surface water, especially available through rivers, is the main source of healthy water for the living beings throughout the world from ancient days as it consists of all essential minerals. With the advent of industrialization, gradually even the most prominent rivers have been polluted in all parts of the world. Although there are lots of technologies, nanofiltration (NF has been chosen to transform river water into healthy water due to its unique advantages of retaining optimum TDS (with essential minerals required for human body, consuming of lower energy, and no usage of any chemicals. The prominent parameters of surface water and macro/microminerals of treated water have been analyzed. It is shown that NF is better in producing healthy water with high flux by consuming low energy.

Effects of Seawater Acidification on the Liffe Cycle and Fitness of Opossum Shrimp Population

Science.gov (United States)

Much of the current concern about ecological effects of ocean acidification focuses on molluscs and coccolithophores because of their importance in the global calcium cycle. However, many other marine organisms are likely to be affected by acidification because of their known se...

Effects of Seawater Acidification on the Life Cycle and fitness of Opossum Shrimp Populations

Science.gov (United States)

Much of the current concern about ecological effects of ocean acidification focuses on molluscs and coccolithophores because of their importance in the global calcium cycle. However, many other marine organisms are likely to be affected by acidification because of their known ph...

Natural acidification changes the timing and rate of succession, alters community structure, and increases homogeneity in marine biofouling communities.

Science.gov (United States)

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

Dynamics of ice nucleation on water repellent surfaces.

Science.gov (United States)

Alizadeh, Azar; Yamada, Masako; Li, Ri; Shang, Wen; Otta, Shourya; Zhong, Sheng; Ge, Liehui; Dhinojwala, Ali; Conway, Ken R; Bahadur, Vaibhav; Vinciquerra, A Joseph; Stephens, Brian; Blohm, Margaret L

2012-02-14

Prevention of ice accretion and adhesion on surfaces is relevant to many applications, leading to improved operation safety, increased energy efficiency, and cost reduction. Development of passive nonicing coatings is highly desirable, since current antiicing strategies are energy and cost intensive. Superhydrophobicity has been proposed as a lead passive nonicing strategy, yet the exact mechanism of delayed icing on these surfaces is not clearly understood. In this work, we present an in-depth analysis of ice formation dynamics upon water droplet impact on surfaces with different wettabilities. We experimentally demonstrate that ice nucleation under low-humidity conditions can be delayed through control of surface chemistry and texture. Combining infrared (IR) thermometry and high-speed photography, we observe that the reduction of water-surface contact area on superhydrophobic surfaces plays a dual role in delaying nucleation: first by reducing heat transfer and second by reducing the probability of heterogeneous nucleation at the water-substrate interface. This work also includes an analysis (based on classical nucleation theory) to estimate various homogeneous and heterogeneous nucleation rates in icing situations. The key finding is that ice nucleation delay on superhydrophobic surfaces is more prominent at moderate degrees of supercooling, while closer to the homogeneous nucleation temperature, bulk and air-water interface nucleation effects become equally important. The study presented here offers a comprehensive perspective on the efficacy of textured surfaces for nonicing applications.

Roles of surface water areas for water and solute cycle in Hanoi city, Viet Nam

Science.gov (United States)

Hayashi, Takeshi; Kuroda, Keisuke; Do Thuan, An; Tran Thi Viet, Nga; Takizawa, Satoshi

2013-04-01

Hanoi city, the capital of Viet Nam, has developed beside the Red river. Recent rapid urbanization of this city has reduced a large number of natural water areas such as lakes, ponds and canals not only in the central area but the suburban area. Contrary, the urbanization has increased artificial water areas such as pond for fish cultivation and landscaping. On the other hand, the urbanization has induced the inflow of waste water from households and various kinds of factories to these water areas because of delay of sewerage system development. Inflow of the waste water has induced eutrophication and pollution of these water areas. Also, there is a possibility of groundwater pollution by infiltration of polluted surface water. However, the role of these water areas for water cycle and solute transport is not clarified. Therefore, this study focuses on the interaction between surface water areas and groundwater in Hanoi city to evaluate appropriate land development and groundwater resource management. We are carrying out three approaches: a) understanding of geochemical characteristics of surface water and groundwater, b) monitoring of water levels of pond and groundwater, c) sampling of soil and pond sediment. Correlation between d18O and dD of precipitation (after GNIP), the Red River (after GNIR) and the water samples of this study showed that the groundwater is composed of precipitation, the Red River and surface water that has evaporation process. Contribution of the surface water with evaporation process was widely found in the study area. As for groundwater monitoring, the Holocene aquifers at two sites were in unconfined condition in dry season and the groundwater levels in the aquifer continued to increase through rainy season. The results of isotopic analysis and groundwater level monitoring showed that the surface water areas are one of the major groundwater sources. On the other hand, concentrations of dissolved Arsenic (filtered by 0.45um) in the pore

International Cooperative Programme for Assessment and Monitoring of Acidification of Rivers and Lakes. Programme Manual

Energy Technology Data Exchange (ETDEWEB)

Bowman, J.; Forsius, M.; Jeffries, D. [and others

1996-12-31

The International Cooperative Programme for Assessment of Acidification of Rivers and lakes (ICP Waters) was established in 1985 by the UN/ECE Executive Body for the Convention of Long-Range Transboundary Air Pollution. Achieving the programme objectives requires that both the temporally intensive and regionally extensive data are collected on a continuing basis. To guide the development and harmonization of the various national contributions, a manual was worked out. The present report is an expanded and consolidated revision of that manual. 33 refs., 3 tabs.

Quantifying spatially derived carrying capacity occupation: Framework for characterisation modelling and application to terrestrial acidification

DEFF Research Database (Denmark)

Bjørn, Anders; Margni, M.; Bulle, C.

*year. This metric resembles that of the ecological footprint method and may be compared to the availability of land or water. The framework was applied to the terrestrial acidification impact category. The geochemical steady-state model PROFILE was used to quantify carrying capacities as deposition levels......The popularity of the ecological footprint method and the planetary boundaries concept shows an increasing interest among decision makers in comparing environmental impacts to carrying capacities of natural systems. Recently carrying capacity-based normalisation references were developed for impact...

IPCC workshop on impacts of ocean acidification on marine biology and ecosystems. Workshop report

Energy Technology Data Exchange (ETDEWEB)

Field, C.B.; Barros, V.; Stocker, T.F.; Dahe, Q.; Mach, K.J.; Plattner, G.-K.; Mastrandrea, M.D.; Tignor, M.; Ebi, K.L.

2011-09-15

Understanding the effects of increasing atmospheric CO{sub 2} concentrations on ocean chemistry, commonly termed ocean acidification, as well as associated impacts on marine biology and ecosystems, is an important component of scientific knowledge about global change. The Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change (IPCC) will include comprehensive coverage of ocean acidification and its impacts, including potential feedbacks to the climate system. To support ongoing AR5 assessment efforts, Working Group II and Working Group I (WGII and WGI) of the IPCC held a joint Workshop on Impacts of Ocean Acidification on Marine Biology and Ecosystems in Okinawa, Japan, from 17 to 19 January 2011. The workshop convened experts from the scientific community, including WGII and WGI AR5 authors and review editors, to synthesise scientific understanding of changes in ocean chemistry due to increased CO{sub 2} and of impacts of this changing chemistry on marine organisms, ecosystems, and ecosystem services. This workshop report summarises the scientific content and perspectives presented and discussed during the workshop. It provides syntheses of these perspectives for the workshop's core topics: (i) the changing chemistry of the oceans, (ii) impacts of ocean acidification for individual organisms, and (iii) scaling up responses from individual organisms to ecosystems. It also presents summaries of workshop discussions of key cross-cutting themes, ranging from detection and attribution of ocean acidification and its impacts to understanding ocean acidification in the context of other stressors on marine systems. Additionally, the workshop report includes extended abstracts for keynote and poster presentations at the workshop. (Author)

Ocean Acidification Accelerates the Growth of Two Bloom-Forming Macroalgae.

Science.gov (United States)

Young, Craig S; Gobler, Christopher J

2016-01-01

While there is growing interest in understanding how marine life will respond to future ocean acidification, many coastal ecosystems currently experience intense acidification in response to upwelling, eutrophication, or riverine discharge. Such acidification can be inhibitory to calcifying animals, but less is known regarding how non-calcifying macroalgae may respond to elevated CO2. Here, we report on experiments performed during summer through fall with North Atlantic populations of Gracilaria and Ulva that were grown in situ within a mesotrophic estuary (Shinnecock Bay, NY, USA) or exposed to normal and elevated, but environmentally realistic, levels of pCO2 and/or nutrients (nitrogen and phosphorus). In nearly all experiments, the growth rates of Gracilaria were significantly increased by an average of 70% beyond in situ and control conditions when exposed to elevated levels of pCO2 (p0.05). The δ13C content of both Gracilaria and Ulva decreased two-to-three fold when grown under elevated pCO2 (pacidification, a process that will intensify in the coming decades.

AFSC/RACE/SAP/Foy: Effects of ocean acidification on larval Tanner crab: Kodiak Island, Alaska.

Data.gov (United States)

National Oceanic and Atmospheric Administration, Department of Commerce — To study the effects of ocean acidification we examined the effects of ocean acidification on the larval stages of the economically important southern Tanner crab,...

Electrochemical acidification of Kraft black liquor by electrodialysis with bipolar membrane: Ion exchange membrane fouling identification and mechanisms.

Science.gov (United States)

Haddad, Maryam; Mikhaylin, Sergey; Bazinet, Laurent; Savadogo, Oumarou; Paris, Jean

2017-02-15

Integrated forest biorefinery offers promising pathways to sustainably diversify the revenue of pulp and paper industry. In this context, lignin can be extracted from a residual stream of Kraft pulping process, called black liquor, and subsequently converted into a wide spectrum of bio-based products. Electrochemical acidification of Kraft black liquor by electrodialysis with bipolar membrane results in lignin extraction and caustic soda production. Even though the implementation of this method requires less chemicals than the chemical acidification process, fouling of the ion exchange membranes and especially bipolar membrane impairs its productivity. Membrane thickness and ash content measurements along with scanning electron microscopy (SEM), elemental analysis (EDX) and X-ray photoelectron spectrometry (XPS) analysis were performed to identify the nature and mechanisms of the membrane fouling. The results revealed that the fouling layer mostly consisted of organic components and particularly lignin. Based on our proposed fouling mechanisms, throughout the electrodialysis process the pH of the black liquor gradually decreased and as a result more proton ions were available to trigger protonation reaction of lignin phenolic groups and decrease the lignin solubility. Due to the abundance of the proton ions on the surface of the cation exchange layers of the bipolar membrane, destabilized lignin macro-molecules started to self-aggregate and formed lignin clusters on its surface. Over the time, these lignin clusters covered the entire surface of the bipolar membrane and the spaces between the membranes and, eventually, attached to the surface of the cation exchange membrane. Copyright © 2016 Elsevier Inc. All rights reserved.

Total Nitrogen in Surface Water

Data.gov (United States)

U.S. Environmental Protection Agency — Excess nitrogen in surface water can result in eutrophication. TOTALN is reported in kilograms/hectare/year. More information about these resources, including the...

Total Phosphorus in Surface Water

Data.gov (United States)

U.S. Environmental Protection Agency — Excess phosphorus in surface water can result in eutrophication. TOTALP is reported in kilograms/hectare/year. More information about these resources, including the...

Characteristics of pulse corona discharge over water surface

Science.gov (United States)

Fujii, Tomio; Arao, Yasushi; Rea, Massimo

2008-12-01

Production of ozone and OH radical is required to advance the plasma chemical reactions in the NOx removal processes for combustion gas treatment. The corona discharge to the water surface is expected to induce the good conditions for the proceeding of the NO oxidation and the NO2 dissolution removal into water. In order to get the fundamental data of the corona discharge over the water surface, the positive and negative V-I characteristics and the ozone production were measured with the multi needle and the saw-edge type of the discharge electrodes. The pulse corona characteristics were also measured with some different waveforms of the applied pulse voltage. The experiments were carried out under the atmospheric pressure and room temperature. Both the DC and the pulse corona to the water surface showed a stable and almost the same V-I characteristics as to plate electrodes though the surface of water was waved by corona wind. The positive streamer corona showed more ozone production than the negative one both in the DC and in the pulse corona.

Characteristics of pulse corona discharge over water surface

International Nuclear Information System (INIS)

Fujii, Tomio; Arao, Yasushi; Rea, Massimo

2008-01-01

Production of ozone and OH radical is required to advance the plasma chemical reactions in the NOx removal processes for combustion gas treatment. The corona discharge to the water surface is expected to induce the good conditions for the proceeding of the NO oxidation and the NO 2 dissolution removal into water. In order to get the fundamental data of the corona discharge over the water surface, the positive and negative V-I characteristics and the ozone production were measured with the multi needle and the saw-edge type of the discharge electrodes. The pulse corona characteristics were also measured with some different waveforms of the applied pulse voltage. The experiments were carried out under the atmospheric pressure and room temperature. Both the DC and the pulse corona to the water surface showed a stable and almost the same V-I characteristics as to plate electrodes though the surface of water was waved by corona wind. The positive streamer corona showed more ozone production than the negative one both in the DC and in the pulse corona.

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

Science.gov (United States)

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.

Directory of Open Access Journals (Sweden)

Paulina Kaniewska

Full Text Available 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.

Viral attack exacerbates the susceptibility of a bloom-forming alga to ocean acidification.

Science.gov (United States)

Chen, Shanwen; Gao, Kunshan; Beardall, John

2015-02-01

Both ocean acidification and viral infection bring about changes in marine phytoplankton physiological activities and community composition. However, little information is available on how the relationship between phytoplankton and viruses may be affected by ocean acidification and what impacts this might have on photosynthesis-driven marine biological CO2 pump. Here, we show that when the harmful bloom alga Phaeocystis globosa is infected with viruses under future ocean conditions, its photosynthetic performance further decreased and cells became more susceptible to stressful light levels, showing enhanced photoinhibition and reduced carbon fixation, up-regulation of mitochondrial respiration and decreased virus burst size. Our results indicate that ocean acidification exacerbates the impacts of viral attack on P. globosa, which implies that, while ocean acidification directly influences marine primary producers, it may also affect them indirectly by altering their relationship with viruses. Therefore, viruses as a biotic stressor need to be invoked when considering the overall impacts of climate change on marine productivity and carbon sequestration. © 2014 John Wiley & Sons Ltd.

Red coral extinction risk enhanced by ocean acidification.

Science.gov (United States)

Cerrano, Carlo; Cardini, Ulisse; Bianchelli, Silvia; Corinaldesi, Cinzia; Pusceddu, Antonio; Danovaro, Roberto

2013-01-01

The red coral Corallium rubrum is a habitat-forming species with a prominent and structural role in mesophotic habitats, which sustains biodiversity hotspots. This precious coral is threatened by both over-exploitation and temperature driven mass mortality events. We report here that biocalcification, growth rates and polyps' (feeding) activity of Corallium rubrum are significantly reduced at pCO2 scenarios predicted for the end of this century (0.2 pH decrease). Since C. rubrum is a long-living species (>200 years), our results suggest that ocean acidification predicted for 2100 will significantly increases the risk of extinction of present populations. Given the functional role of these corals in the mesophotic zone, we predict that ocean acidification might have cascading effects on the functioning of these habitats worldwide.

Thermophoretically driven water droplets on graphene and boron nitride surfaces

Science.gov (United States)

Rajegowda, Rakesh; Kannam, Sridhar Kumar; Hartkamp, Remco; Sathian, Sarith P.

2018-05-01

We investigate thermally driven water droplet transport on graphene and hexagonal boron nitride (h-BN) surfaces using molecular dynamics simulations. The two surfaces considered here have different wettabilities with a significant difference in the mode of droplet transport. The water droplet travels along a straighter path on the h-BN sheet than on graphene. The h-BN surface produced a higher driving force on the droplet than the graphene surface. The water droplet is found to move faster on h-BN surface compared to graphene surface. The instantaneous contact angle was monitored as a measure of droplet deformation during thermal transport. The characteristics of the droplet motion on both surfaces is determined through the moment scaling spectrum. The water droplet on h-BN surface showed the attributes of the super-diffusive process, whereas it was sub-diffusive on the graphene surface.