Ocean acidification has been predicted to reduce the ability of marine organisms to produce carbonate skeletons, threatening their long-term viability and severely impacting marine ecosystems. Corals, as ecosystem engineers, have been identified as particularly vulnerable and important. To determine the sensitivity of corals and allied taxa to long-term exposure to very low carbonate concentrations, we examined the distribution and skeletal characteristics of coral taxa along a natural deep-sea concentration gradient on seamounts of SW Australia. Carbonate under-saturation had little evident effect on the depth distribution, growth or skeletal composition of live scleractinians or gorgonians, with corals growing, often abundantly, in waters as much as 20 to 30% under-saturated. Developmental anomalies in the deepest skeleton-forming anthozoan collected (an isidid gorgonian, at nearly 4 km depth) suggest an absolute low tolerance limit of about 40% under-saturation. Evidence for an effect of acidification on the accumulation of reef structure is ambiguous, with clear indications of dissolution of high-magnesium calcite (HMC) gorgonian skeletons at depths below 2300 m, but also abundant, old scleractinian skeletons well below the aragonite saturation horizon. The latter might be the result of ferromanganese deposition on exposed skeletons, which, however, may render them inhospitable for benthic organisms.
Archive for December, 2011
Effects of chronic low carbonate saturation levels on the distribution, growth and skeletal chemistry of deep-sea corals and other seamount megabenthos
Published 13 December 2011 Science ClosedTags: biological response, corals
Perceptions of climate change and adaptation responses in a local community: the Barwon Estuary Complex, Victoria
Published 13 December 2011 Science ClosedTags: biological response, chemistry
The climate change focus in Australia has shifted from mitigation to adaptation with an emphasis on place-specific case studies. The Barwon Estuary Complex (BEC) on the Bellarine Peninsula, central Victoria, was the focus of this place-specific study in which 37 local stakeholders were consulted through a series of semi-structured interviews on the impacts of climate change on their coastal community. Overall there was uniformity in stakeholder perceptions of the climate change impacts and vulnerabilities pertaining to the BEC. In contrast, discussion on adaptation drew a diversity of responses. While 53 per cent of stakeholders indicated a need to limit the use of hard structures, and rather plan around a changing estuarine environment, opinion amongst the community group was divided. Some believed ‘retreat is the only option’ whilst others felt ‘there won’t be much leaving’. The present level of confusion around adaptation highlights the imperative of commencing discussions now to allow sufficient time to develop strategies which are both environmentally and socially responsible. This is important as ultimately it will be the community that will determine whether adaptation strategies are adopted or met with resistance.
B/Ca in coccoliths and relationship to calcification vesicle pH and dissolved inorganic carbon concentrations
Published 13 December 2011 Science ClosedTags: biological response, phytoplankton
Coccolithophorid algae are microscopic but prolific calcifiers in modern and ancient oceans. When the pH of seawater is modified, as may occur in the future due to ocean acidification, different species and strains of coccolithophorids have exhibited diverse calcification responses in laboratory culture. Since their biomineralization is a completely intracellular process, it is unclear why their response should be affected by extracellular seawater pH. Variations in the B/Cain coccoliths are potential indicators of pH shifts in the intracellular coccolith vesicle where calcification occurs, because B/Ca in abiogenic calcites increases at higher pH due to the greater abundance of borate ions, the only B species incorporated into calcite. We used a SIMS ion probe to measure B/Ca of coccoliths from three different strains of Emiliania huxleyi and one strain of Coccolithus braarudiibraarudiicultured under different seawater pH conditions to ascertain if the B/Ca can be used to elucidate how coccolithophorids respond to changing ocean pH.These data are interpreted with the aid of a conceptual model of cellular boron acquisition by coccolithophorids. Based on uptake in other plants, we infer that boron uptake by coccolithophorid cells is dominated by passive uptake of boric acid across the lipid bilayer. Subsequently, in the alkaline coccolith vesicle (C.V.), boron speciates according to the C.V. pH, and borate is incorporated into the coccolith. At increasing seawater pH, the relative abundance of the neutral boric acid in seawater decreases, lowering the potential B flux into the cell. Homeostasis or constant pH of the coccolith vesicle results in a decrease of the B/Cain the coccolith with increasing seawater pH. In contrast, if coccolith vesicle pH increases with increasing seawater pH, then the B/Ca will increase as the fraction of borate in the coccolith vesicle increases. The coccolith B/Ca is also expected to depend inversely on the dissolved inorganic carbon (DIC) concentration in the coccolith vesicle. The B/Ca in cultured coccoliths is much lower than that of foraminifera or corals and limits precision in the analysis. Modest variations in DIC or pH of the coccolith vesicle can account for the observed trends in B/Ca in cultured coccoliths. The model shows that paired measurements of B/Ca and B isotopic composition of the calcite could distinguish between regulation of pH or DIC in the coccolith vesicle.
Interactive effects of salinity and elevated CO2 levels on juvenile eastern oysters, Crassostrea virginica
Published 13 December 2011 Science ClosedTags: biological response, mollusks
Rising levels of atmospheric CO2 lead to acidification of the ocean and alter seawater carbonate chemistry, which can negatively impact calcifying organisms, including mollusks. In estuaries, exposure to elevated CO2 levels often co-occurs with other stressors, such as reduced salinity, which enhances the acidification trend, affects ion and acid–base regulation of estuarine calcifiers and modifies their response to ocean acidification. We studied the interactive effects of salinity and partial pressure of CO2 (PCO2) on biomineralization and energy homeostasis in juveniles of the eastern oyster, Crassostrea virginica, a common estuarine bivalve. Juveniles were exposed for 11 weeks to one of two environmentally relevant salinities (30 or 15 PSU) either at current atmospheric PCO2 (∼400 μatm, normocapnia) or PCO2 projected by moderate IPCC scenarios for the year 2100 (∼700–800 μatm, hypercapnia). Exposure of the juvenile oysters to elevated PCO2 and/or low salinity led to a significant increase in mortality, reduction of tissue energy stores (glycogen and lipid) and negative soft tissue growth, indicating energy deficiency. Interestingly, tissue ATP levels were not affected by exposure to changing salinity and PCO2, suggesting that juvenile oysters maintain their cellular energy status at the expense of lipid and glycogen stores. At the same time, no compensatory upregulation of carbonic anhydrase activity was found under the conditions of low salinity and high PCO2. Metabolic profiling using magnetic resonance spectroscopy revealed altered metabolite status following low salinity exposure; specifically, acetate levels were lower in hypercapnic than in normocapnic individuals at low salinity. Combined exposure to hypercapnia and low salinity negatively affected mechanical properties of shells of the juveniles, resulting in reduced hardness and fracture resistance. Thus, our data suggest that the combined effects of elevated PCO2 and fluctuating salinity may jeopardize the survival of eastern oysters because of weakening of their shells and increased energy consumption.
Moderate acidification affects growth but not survival of 6-month-old oysters
Published 13 December 2011 Science ClosedTags: biological response, mollusks
Oyster populations periodically exposed to runoff from acid sulfate soils (ASS) are of depressed abundance and have fewer smaller individuals than unaffected populations, despite having similar recruitment levels to unaffected sites during dry periods. We examined how the timing and duration of exposure to ASS runoff influences the growth and survival of successfully settled oysters. We predicted that among 6-month-old oysters, growth and survival would be (1) lower among individuals continuously exposed to ASS-acidified waters than those that are episodically exposed, and (2) most negatively affected during rainfall events, which enhance transport of ASS runoff to estuaries. Six-month-old Sydney rock oysters, Saccostrea glomerata, were deployed at ASS-affected and unaffected sites within each of two south-east Australian estuaries. After 10 weeks, oysters were transplanted within and across sites in an estuary and maintained in situ for another 10 weeks. Oysters that remained for 20 weeks at ASS-affected sites grew at just over half the rate of oysters at reference sites. Oysters transplanted from acidified to reference sites grew more than oysters transplanted from reference to acidified sites or oysters that remained at reference sites. Unexpectedly, overall oyster mortality was low. Greater rainfall, and hence a lower pH, is likely to have accounted for the greater impact of acidification on growth during the second 10 weeks. Where oysters recruit to a 6-month age cohort, they may be able to tolerate subsequent, moderate, acidification events. Reduced growth during acidification periods may be offset by positive growth during intervening dry periods.
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Impacts of CO2-driven seawater acidification on survival, egg production rate and hatching success of four marine copepods
Published 13 December 2011 Science ClosedTags: biological response, zooplankton
Ecological experiments were conducted to examine the effects of seawater containing elevated partial pressure of carbon dioxide (pCO2 800×10−6, 2 000×10−6, 5 000×10−6 and 10 000×10−6) on the survival and reproduction of female Acartia pacifica, Acartia spinicauda, Calanus sinicus and Centropages tenuiremis, which are the dominant copepods in the southern coastal waters of China. The results show that the effects of elevated pCO2 on the survival rates of copepods were speciesspecific. C. sinicus, which was a macro-copepod, had a higher survival rate (62.01%–71.96%) than the other three species (5.00%–26.67%) during the eight day exposure. The egg production rates of C. sinicus, A. spinicauda and C. tenuiremis were significantly inhibited by the increased pCO2 and the exposure time duration. There were significantly negative impacts on the egg hatching success of A. spinicauda and C. tenuiremis in the pCO2 2 000×10−6 and 10 000×10−6 groups, and, in addition, the exposure time had noticeably impacts on these rates too. This study indicates that the reproductive performances of copepods were sensitive to elevated pCO2, and that the response of different copepod species to acidified seawater was different. Furthermore, the synergistic effects of seawater acidification and climate change or other pollutant stresses on organisms should be given more attention.
Effect of ocean acidification on coastal phytoplankton composition and accompanying organic nitrogen production
Published 13 December 2011 Science ClosedTags: biological response, chemistry, phytoplankton
The effect of ocean acidification, caused by the increase in pCO2 in seawater, on phytoplankton population and on related organic nitrogen production was experimentally examined by use of a natural coastal microbial population. pCO2 and pH were controlled by aeration with air in which pCO2 was at the current level (control), for which ambient air was used, and with air in which pCO2 was “800” and “1200” ppm, in 500-L culture vessels. The experiment was continued for 15 days after addition of the inorganic nutrients such as nitrate, phosphate, and silicate. During most of the experimental period, a minor increase in phytoplankton biomass was noted, probably because of low irradiance, an increase in phytoplankton biomass was observed at the end of the experiment. Flow cytometric and microscopic observations revealed that this increase was because of Chrysochromulina sp. (Haptophyceae). The growth of Chrysochromulina sp. was most obvious in the control vessel, and tended to be obscured by increasing pCO2 (decrease in pH), indicating the possibility that ocean acidification inhibits the growth of specific phytoplankton groups, for example Chrysochromulina sp. Production of particulate organic nitrogen (PON), determined by the 15N tracer method, also diminished under acidified conditions compared with that at the current level.
Changes in South Pacific anthropogenic carbon
Published 13 December 2011 Science ClosedTags: chemistry
The changes in anthropogenic CO2 are evaluated in the South Pacific, along the meridional line P18 (110°W) and the zonal line P06 (32°S), using the extended multiple linear regression (eMLR) method. The structure of the column inventory of anthropogenic CO2 on P18 is similar to the southern section of P16 in the central South Pacific (150°W), but the overall increase is greater by approximately 5–10 μmol kg−1. The value of the anthropogenic CO2 inventory on P18 is in agreement at the crossover point of an earlier evaluation of P06. Subsequent changes in pH due to the increase in anthropogenic CO2 are also evaluated. The change in pH is determined from the changes in anthropogenic CO2 and do not reflect variability in other decadal signals. For both cruise tracks, the average annual change in pH is −0.0016 mol kg−1 yr−1. This value is in good agreement with the average decrease in pH in the North Pacific, at the Hawaii Times Series and the subtropical North Atlantic. The uptake rates of anthropogenic CO2 are within reasonable agreement with similar studies in the South Pacific. There is evidence for greater uptake of anthropogenic CO2 in the western South Pacific and is attributed to the formation of subtropical Mode Water in the region.
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Rolling stones; fast weathering of olivine in shallow seas for cost-effective CO2 capture and mitigation of global warming and ocean acidification
Published 13 December 2011 Science ClosedTags: biogeochemistry
Human CO2 emissions may drive the Earth into a next greenhouse state. They can be mitigated by accelerating weathering of natural rock under the uptake of CO2. We disprove the paradigm that olivine weathering in nature would be a slow process, and show that it is not needed to mill olivine to very fine, 10 μm-size grains in order to arrive at a complete dissolution within 1–2 year. In high-energy shallow marine environments olivine grains and reaction products on the grain surfaces, that otherwise would greatly retard the reaction, are abraded so that the chemical reaction is much accelerated. When kept in motion even large olivine grains rubbing and bumping against each other quickly produce fine clay- and silt-sized olivine particles that show a fast chemical reaction. Spreading of olivine in the world’s 2% most energetic shelf seas can compensate a year’s global CO2 emissions and counteract ocean acidification against a price well below that of carbon credits.
Interactions between ocean acidification and warming on the mortality and dissolution of coralline algae
Published 13 December 2011 Science ClosedTags: algae
Coralline algae are among the most sensitive calcifying organisms to ocean acidification as a result of increased atmospheric carbon dioxide (pCO2). Little is known, however, about the combined impacts of increased pCO2, ocean acidification, and sea surface temperature on tissue mortality and skeletal dissolution of coralline algae. To address this issue, we conducted factorial manipulative experiments of elevated CO2 and temperature and examined the consequences on tissue survival and skeletal dissolution of the crustose coralline alga (CCA) Porolithon (=Hydrolithon) onkodes (Heydr.) Foslie (Corallinaceae, Rhodophyta) on the southern Great Barrier Reef (GBR), Australia. We observed that warming amplified the negative effects of high pCO2 on the health of the algae: rates of advanced partial mortality of CCA increased from <1% to 9% under high CO2 (from 400 to 1,100 ppm) and exacerbated to 15% under warming conditions (from 26°C to 29°C). Furthermore, the effect of pCO2 on skeletal dissolution strongly depended on temperature. Dissolution of P. onkodes only occurred in the high-pCO2 treatment and was greater in the warm treatment. Enhanced skeletal dissolution was also associated with a significant increase in the abundance of endolithic algae. Our results demonstrate that P. onkodes is particularly sensitive to ocean acidification under warm conditions, suggesting that previous experiments focused on ocean acidification alone have underestimated the impact of future conditions on coralline algae. Given the central role that coralline algae play within coral reefs, these conclusions have serious ramifications for the integrity of coral-reef ecosystems.
C-CAN blog: Collection of coastal ocean data by the Central Bight Cooperative Water Quality Survey (CBCWQS)
Published 13 December 2011 Web sites and blogs ClosedA consortium of Southern California POTWs coordinate coastal ocean monitoring efforts required by their individual NPDES permits for ocean discharge of treated wastewater. Coordinated monitoring is done quarterly on the 1st week of February, May, August and November at over 300 sites using multiple vessels and Sea-Bird CTDs equipped with pH, chlorophyll-a and CDOM fluorescence, light transmissometer and DO sensors.
The POTWs are required to meet all conditions in the California Ocean Plan (COP) immediately outside an initial dilution zone around their outfalls. For pH, the COP specifies “The pH shall not be changed at any time more than 0.2 units from that which occurs naturally”. Permits require continuous pH monitoring of effluent. Recent JWPCP effluent had an average pH of 7.15, alkalinity of 330-430 mg/l, and a predicted CO2 for typical effluent properties of 20 mg/l. Dilution tank tests in seawater observed pH change from 8.17 down to 8.15 as effluent was added to lower dilution from 2000:1 to 100:1. The resolution of the Sea-Bird, Inc pH sensor is 0.1 pH unit under optimal conditions.
Marine science researchers release study suggesting ocean acidification may directly harm fish
Published 13 December 2011 Media coverage ClosedFossil fuel combustion, and with it the release of heat-trapping carbon dioxide (CO2), is still growing globally.1 Beyond climate change, this is also causing the world’s “other CO2 problem,” ocean acidification, i.e., the formation of carbonic acid when CO2 from the atmosphere enters seawater. Studies have already demonstrated a multitude of negative effects of elevated CO2 conditions for many groups of marine organisms such as corals, plankton, shellfish and sea urchins. To date, scientists have assumed marine fish were immune to ocean acidification.
However, in a new article published in the December 11, 2011, online edition of the journal Nature Climate Change, researchers from Stony Brook University (NY, USA) demonstrate that “the fish are okay” belief ignores an important knowledge gap – the possible effects of CO2 during the early development of fish eggs and larvae. Co-authors of the study, Christopher Gobler and Hannes Baumann, are professors at the Stony Brook University School of Marine and Atmospheric Science (SoMAS) and represent one of several international teams working on closing this gap.
Reduced early life growth and survival in a fish in direct response to increased carbon dioxide
Published 13 December 2011 Science ClosedTags: biological response, fish
Absorption of anthropogenic carbon dioxide by the world’s oceans is causing mankind’s ‘other CO2 problem’, ocean acidification. Although this process will challenge marine organisms that synthesize calcareous exoskeletons or shells, it is unclear how it will affect internally calcifying organisms, such as marine fish. Adult fish tolerate short-term exposures to CO2 levels that exceed those predicted for the next 300 years (~2,000 ppm), but potential effects of increased CO2 on growth and survival during the early life stages of fish remain poorly understood. Here we show that the exposure of early life stages of a common estuarine fish (Menidia beryllina) to CO2 concentrations expected in the world’s oceans later this century caused severely reduced survival and growth rates. When compared with present-day CO2 levels (~400 ppm), exposure of M. beryllina embryos to ~1,000 ppm until one week post-hatch reduced average survival and length by 74% and 18%, respectively. The egg stage was significantly more vulnerable to high CO2-induced mortality than the post-hatch larval stage. These findings challenge the belief that ocean acidification will not affect fish populations, because even small changes in early life survival can generate large fluctuations in adult-fish abundance.
The Problem:
Anthropogenic carbon dioxide emissions are resulting in increased concentrations of CO2 in the world’s oceans leading to reductions in pH and carbonate saturation state with subsequent impacts to calcifying marine organisms. This so called “ocean acidification” is expected to alter the growth and calcification rates of numerous marine organisms-most notably those that have shells or skeletons. The more acidic conditions associated with the current and changing ocean chemistry are expected to alter the carbonate saturation states in seawater thereby making it more difficult for organisms to build carbonate structures or to secrete skeletons and shells. If CO2 emissions continue at present rates, OA could have profound impacts on marine ecosystems globally.
Ocean acidification affects larval and juvenile growth in the Olympia oyster, Ostrea lurida
Published 13 December 2011 Science ClosedTags: biological response, mollusks
Continue reading ‘Ocean acidification affects larval and juvenile growth in the Olympia oyster, Ostrea lurida’
Over a century after the Discovery Expedition (1901-04), our understanding of the environments and ecosystems in the Southern Ocean is still limited. Research efforts have focused on warming and ice melt as the environment changes. Now a new challange has emerged – ocean acidification – a concept that could not even have been comprehended 110 years ago as the ph was only defined in 1909.
Interannual variability of carbon fluxes in the North Sea from 1970 to 2006 – Competing effects of abiotic and biotic drivers on the gas-exchange of CO2
Published 12 December 2011 Science ClosedTags: chemistry
The three-dimensional biogeochemical model ECOHAM was applied to the Northwest European Continental Shelf (NECS) (47° 41′ – 63° 53′ N, 15° 5′ W – 13° 55′ E) for the years 1970–2006. The development of annual carbon fluxes was analysed for the North Sea as the inner shelf region. We divided the North Sea into several regions, the northern North Sea, the southern North Sea, the German Bight and the Southern Bight for a more detailed analysis. To separate the effect of physical and biological processes a second simulation without biology was performed. The results of our method for calculating the biological pCO2 were in good agreement with the biological pCO2 calculated after the method of Takahashi et al. (2002). While in the standard run the North Sea acted as sink for atmospheric CO2, in the run without biology the North Sea was a continuous source for atmospheric CO2.
The main drivers of the air-sea flux variability were identified as being temperature, net ecosystem production and pH. The eutrophication due to high riverine nutrient inputs during the 1980s had no significant effect on the air-sea flux of CO2 because in contrast to net primary production, net ecosystem production did not respond to the period of higher phosphate input. The increase of sea surface temperature of 0.027 °C yr−1 over the simulation period and the pH decline of 0.002 yr−1 led to a decline of the uptake of atmospheric CO2 by the North Sea of about 30% in the last decade of the simulation period. A special feature occurred in the year 1996, where a cold sea surface temperature anomaly led to an additional (physical) uptake of atmospheric CO2 and corresponded with a low primary and net ecosystem production, which on the other hand led to less biologically induced uptake of CO2.
Our results indicate an ongoing decline of the uptake capacity for atmospheric carbon dioxide of the North Sea for future scenarios.
The state’s shellfish industry, besieged by pollution problems and neighbors who don’t want new and expanded geoduck farms, received a fresh show of support Friday from top state and federal officials.
Gov. Chris Gregoire, NOAA administrator Jane Lubchenco and others gathered at Taylor Shellfish Farms’ headquarters in a pep rally-like atmosphere to announce a new shellfish initiative to restore and expand the state’s shellfish resources.
The initiative calls for a streamlined, faster-paced permitting process for new and expanded shellfish farms, stepped-up restoration projects for two native shellfish populations – the Olympia oyster and pinto abalone – and new water-quality projects in shellfish-growing areas of Puget Sound.
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Details of the initiative include:
- The governor will appoint a blue-ribbon panel of scientists and others to create a plan for monitoring and combatting ocean acidification. Rising ocean acidity associated with greenhouse gases can lead to increased mortality in shellfish.
- The U.S. Environmental Protection Agency will direct $4.5 million to local governments and health districts to reduce bacterial contamination from failing septic systems, farm animals, pets and boats. Thurston and Pierce are among the five counties offered funding.
- Helping to recover Olympia oysters by restoring 19 natural oyster beds in Puget Sound by 2022.
- Increasing public access to shellfish on public tidelands for recreational and tribal harvest through new signs, maps and land acquisition.
AGU Fall Meeting: the (pH) lowdown on ocean acidification
Published 12 December 2011 Web sites and blogs ClosedOcean acidification is often overlooked as a problem in favour of its more famous parent, climate change. But it’s receiving plenty of attention at the AGU Fall Meeting in San Francisco.
Whilst most information on the effects of acidification is based on modelling or lab experiments over limited time periods, Adina Paytan of the University of California Santa Cruz has been looking at whole ecosystems – the natural submarine springs, or “ojos”, that occur along Caribbean coastlines. Formed when rainwater travels through limestone caves under land and discharges into the sea via faultlines, these springs have a low pH, making them a natural laboratory for studying the effects of acidification on ocean-dwelling species over long timescales.
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Ocean Acidification – Research notes from the School of Aquatic and Fishery Sciences
Published 12 December 2011 Web sites and blogs ClosedThis website has been developed to serve as a portal for information on active research on ocean acidification within the School of Aquatic and Fishery Sciences at the University of Washington. Project highlights are provided below with occasional posts found in the adjacent column. In general most of our research focuses on how changing ocean conditions impact marine invertebrates.
