Archive for September, 2016

Building support for carbon emissions mitigation: can we use an ocean acidification frame to promote support?

Increasing public support for carbon emissions mitigation is crucial for solving global issues like climate change and ocean acidification (OA). Yet carbon emissions mitigation policies are typically discussed in the context of climate change and hardly ever in the context of OA. In this paper, we present carbon emissions in five different contexts (climate change, global warming, carbon pollution, air pollution, and ocean acidification) and use an online survey tool—with a politically diverse sample of the US population—to measure support for mitigation policies. Though air pollution mitigation receives the highest amount of policy support overall, OA mitigation receives higher levels of support than carbon pollution, climate change, and global warming from conservatives who have heard of ocean acidification. This finding, coupled with other trends in OA perceptions has interesting potential for future risk communication and carbon emissions mitigation policies; OA may offer a new way to engage conservatives in carbon mitigation policy.

Continue reading ‘Building support for carbon emissions mitigation: can we use an ocean acidification frame to promote support?’

Metabolic responses to high pCO2 conditions at a CO2 vent site in juveniles of a marine isopod species assemblage

We are starting to understand the relationship between metabolic rate responses and species’ ability to respond to exposure to high pCO2. However, most of our knowledge has come from investigations of single species. The examination of metabolic responses of closely related species with differing distributions around natural elevated CO2 areas may be useful to inform our understanding of their adaptive significance. Furthermore, little is known about the physiological responses of marine invertebrate juveniles to high pCO2, despite the fact they are known to be sensitive to other stressors, often acting as bottlenecks for future species success. We conducted an in situ transplant experiment using juveniles of isopods found living inside and around a high pCO2 vent (Ischia, Italy): the CO2 ‘tolerant’ Dynamene bifida and ‘sensitive’ Cymodoce truncata and Dynamene torelliae. This allowed us to test for any generality of the hypothesis that pCO2 sensitive marine invertebrates may be those that experience trade-offs between energy metabolism and cellular homoeostasis under high pCO2 conditions. Both sensitive species were able to maintain their energy metabolism under high pCO2 conditions, but in C. truncata this may occur at the expense of [carbonic anhydrase], confirming our hypothesis. By comparison, the tolerant D. bifida appeared metabolically well adapted to high pCO2, being able to upregulate ATP production without recourse to anaerobiosis. These isopods are important keystone species; however, given they differ in their metabolic responses to future pCO2, shifts in the structure of the marine ecosystems they inhabit may be expected under future ocean acidification conditions.

Continue reading ‘Metabolic responses to high pCO2 conditions at a CO2 vent site in juveniles of a marine isopod species assemblage’

Intraspecific variability in the response to ocean warming and acidification in the scleractinian coral Acropora pulchra

Studies of coral colonies show that ocean acidification and temperature can affect calcification; however, less is known about the consequences for their populations. Understanding intraspecific variation in the response of corals to these conditions will be important for evaluating population-level consequences of environmental change. We examined intraspecific variability in the effects of elevated temperature and carbon dioxide levels on net calcification (Gn) in the coral Acropora pulchra in Moorea, French Polynesia. A common garden experiment showed that Gn in four colonies was affected negatively by high partial pressure of CO2 (pCO2) (~1000 μatm cf. ~400 μatm ambient conditions), whereas elevated temperature (30 °C cf. 27 °C) had a negative effect on one colony. Together, these results reveal intraspecific variation in the response of Gn to temperature but not to pCO2. The fastest growing colonies under ambient temperature and ambient pCO2 showed the greatest decline in Gn at high temperature and elevated pCO2. For reef corals, effects of temperature and pCO2 on calcification that depend on the intrinsic growth rate have potentially important consequences, because they imply that coral colonies contributing the most to population-level calcification will be disproportionately affected by changing environmental conditions.

Continue reading ‘Intraspecific variability in the response to ocean warming and acidification in the scleractinian coral Acropora pulchra’

Sea sponges likely to weather climate change: New Zealand study

WELLINGTON, Sept. 29 (Xinhua) — Some species of sea sponge could be “winners” in global climate change and ocean acidification, New Zealand scientists said Thursday.

Researchers from Victoria University of Wellington examined the physiological responses of four Great Barrier Reef sponge species in response to rising acidification and seawater temperature.

They found that while all four species were sensitive to predicted ocean warming, their sensitivity reduced under ocean acidification for sponges that received their nutrition from symbiotic organisms which get their energy from the sun.

“Our results show that some sponges may be able to deal with future predicted ocean conditions, making them future ‘winners’ under global climate change,” researcher Holly Bennett said in a statement.

The study also found that early-life stages of sponges exhibited greater tolerance to ocean warming than their adult counterparts, which was likely to be crucial to the survival and adaptive capacity of some sponges.

Continue reading ‘Sea sponges likely to weather climate change: New Zealand study’

Disparate acidification and calcium carbonate desaturation of deep and shallow waters of the Arctic Ocean

The Arctic Ocean is acidifying from absorption of man-made CO2. Current predictive models of that acidification focus on surface waters, and their results argue that deep waters will acidify by downward penetration from the surface. Here we show, with an alternative model, the rapid, near simultaneous, acidification of both surface and deep waters, a prediction supported by current, but limited, saturation data. Whereas Arctic surface water responds directly by atmospheric CO2 uptake, deeper waters will be influenced strongly by intrusion of mid-depth, pre-acidified, Atlantic Ocean water. With unabated CO2 emissions, surface waters will become undersaturated with respect to aragonite by 2105 AD and could remain so for ∼600 years. In deep waters, the aragonite saturation horizon will rise, reaching the base of the surface mixed layer by 2140 AD and likely remaining there for over a millennium. The survival of aragonite-secreting organisms is consequently threatened on long timescales.

Continue reading ‘Disparate acidification and calcium carbonate desaturation of deep and shallow waters of the Arctic Ocean’

Combined effects of elevated pCO2 and temperature on biomass and carbon fixation of phytoplankton assemblages in the northern South China Sea

The individual influences of ocean warming and acidification on marine organisms have been investigated intensively, but studies regarding the combined effects of both global change variables on natural marine phytoplankton assemblages are still scarce. Even fewer studies have addressed possible differences in the responses of phytoplankton communities in pelagic and coastal zones to ocean warming and acidification. We conducted shipboard microcosm experiments at both off-shore (SEATS) and near-shore (D001) stations in the northern South China Sea (NSCS) under three treatments, low temperature (30.5 °C at SEATS and 28.5 °C at D001) and low pCO2 (390.0 µatm at SEATS and 420.0 µatm at D001) (LTLC), high temperature (33.5 °C at SEATS and 31.5 °C at D001) and low pCO2 (390 µatm at SEATS and 420 µatm at D001) (HTLC), and high temperature (33.5 °C at SEATS and 31.5 °C at D001) and high pCO2 (1000 µatm at SEATS and 1030 µatm at D001) (HTHC). Biomass of phytoplankton at both stations were enhanced by HT. HTHC did not affect phytoplankton biomass at station D001 but decreased it at station SEATS. At this offshore station HT alone increased daily primary productivity (DPP, µgC (µg chl a)−1 d−1) by ~ 64 %, and by ~ 117 % when higher pCO2 was added. In contrast, HT alone did not affect DPP and HTHC reduced it by ~ 15 % at station D001. HT enhanced the dark respiration rate (µg C (µg chl a)-1 d−1) by 64 % at station SEATS, but had no significant effect at station D001, and did not change the ratio of respiration to photosynthesis at either station. HTHC did not affect dark respiration rate (µg C (µg chl a)−1 d−1) at either station compared to LTLC. HTHC reduced the respiration to photosynthesis ratio by ~ 41 % at station SEATS but increased it ~ 42 % at station D001. Overall, our findings indicate that responses of coastal and offshore phytoplankton assemblages in NSCS to ocean warming and acidification are contrasting, with the pelagic phytoplankton communities being more sensitive to these two global change factors.

Continue reading ‘Combined effects of elevated pCO2 and temperature on biomass and carbon fixation of phytoplankton assemblages in the northern South China Sea’

Effects of elevated carbon dioxide and temperature on survival and morphology of Japanese whiting Sillago japonica

The objective of the present study was to examine the effect of elevated CO2 and temperature on survival and morphology of Sillago japonica yolk sac larvae under the Institute for East China Sea Research(ECSER) Nagasaki, Japan. In this study, we examined hatching success, survival and morphology of the larvae of Sillago japonica under four conditions: control (C), seawater pCO2 382µatm, temperature 27 °C; high CO2 (HC), 915µatm, 27 °C; high temperature (HT), 385 µatm, 31 oC; and high CO2+high temperature (HCT), 932µatm, 31 oC. Fertilized eggs were obtained from broodstock reared in natural seawater, and transferred to experimental containers in each treatment. Hatched larvae were observed until the completion of yolk sac absorptions on 3 days post hatching (dph). The experiment was repeated four times with 4 replicates for each treatment in each experiment. Also, the temperature appeared to have exerted a stronger influence on hatching success (Hs) and larval survival (Sv): Hs and Sv at 3 dph were both significantly (p>0.05) depressed in HT (Hs 52.5±1.25%, Sv 23.8±4.38%) and HCT (Hs 51.3±3.13%, Sv 20.0±0.63%) treatments than in C (Hs 98.1±0.94%, Sv 74.4±2.03%) and HC (Hs 95.0±2.5%, Sv 49.7±3.44%) treatments. In contrast, CO2 was the predominant factor responsible for morphological abnormality: percentage morphological abnormality was significantly (p>0.05) higher in HC (15.8±2.72%) and HCT (41.0±10.86%) treatments than in C (0.4±0.65%) and HT (2.4±2.40%) treatments. Most individuals in HC and HCT treatments had body axis either curved or bent, with aberrant swimming behavior. These results indicate that projected future ocean environments will have significant negative impacts on hatching success, and larval survival and morphology of S. japonica, which might have serious ramifications for recruitment of the species. Comparative studies on other teleost and elasmobranch species are critically needed.

Continue reading ‘Effects of elevated carbon dioxide and temperature on survival and morphology of Japanese whiting Sillago japonica’

Missions CARIOCA – Papouasie-Nouvelle-Guinée – Acclimatation des coraux à l’acidification des océans (in French)

Une équipe internationale pilotée par l’IRD embarque à bord de l’Alis pour étudier en Papouasie-Nouvelle-Guinée des espèces de coraux capables de se développer dans des sites naturellement plus acides. Objectif : en savoir plus sur leur capacité d’acclimatation et d’adaptation aux conditions prévues d’ici la fin du siècle dans le cadre du changement climatique.
En péril… Plus de la moitié des récifs coralliens dans le monde sont menacés de disparition par le changement climatique. Outre l’élévation de la température,  l’augmentation dans l’atmosphère du dioxyde de carbone CO2, engendre une plus grande absorption de ce gaz par l’océan. Environ 800 kg de CO2 sont ainsi dissous dans les mers et océans de la planète par seconde. Sans ce puits de carbone, l’effet de serre sur la Terre serait encore plus important. Mais l’augmentation de ce phénomène provoque une acidification de l’océan et perturbe la biologie des organismes marins. Pour les coraux bâtisseurs de récifs, ceci se traduit par une plus grande difficulté à construire leur squelette calcaire et par une  augmentation de sa dissolution. Or les récifs coralliens hébergent un tiers de la biodiversité marine et fournissent des biens et des services écosystémiques à plus de 500 millions de personnes dans le monde.

Continue reading ‘Missions CARIOCA – Papouasie-Nouvelle-Guinée – Acclimatation des coraux à l’acidification des océans (in French)’

A direct CO2 control system for ocean acidification experiments: testing effects on the coralline red algae Phymatolithon lusitanicum

Most ocean acidification (OA) experimental systems rely on pH as an indirect way to control CO2. However, accurate pH measurements are difficult to obtain and shifts in temperature and/or salinity alter the relationship between pH and pCO2. Here we describe a system in which the target pCO2 is controlled via direct analysis of pCO2 in seawater. This direct type of control accommodates potential temperature and salinity shifts, as the target variable is directly measured instead of being estimated. Water in a header tank is permanently re-circulated through an air-water equilibrator. The equilibrated air is then routed to an infrared gas analyzer (IRGA) that measures pCO2 and conveys this value to a Proportional-Integral-Derivative (PID) controller. The controller commands a solenoid valve that opens and closes the CO2 flush that is bubbled into the header tank. This low-cost control system allows the maintenance of stabilized levels of pCO2 for extended periods of time ensuring accurate experimental conditions. This system was used to study the long term effect of OA on the coralline red algae Phymatolithon lusitanicum. We found that after 11 months of high CO2 exposure, photosynthesis increased with CO2 as opposed to respiration, which was positively affected by temperature. Results showed that this system is adequate to run long-term OA experiments and can be easily adapted to test other relevant variables simultaneously with CO2, such as temperature, irradiance and nutrients.

Continue reading ‘A direct CO2 control system for ocean acidification experiments: testing effects on the coralline red algae Phymatolithon lusitanicum’

Ocean Acidification “State of the Science” Workshop, 30 November – 1 December 2016, Anchorage, Alaska

Date and time: November 30, 2016 9:00 AM – December 1, 2016 6:00 PM (AKST)

Location: Anchorage Downtown Marriott

Registration: This workshop is free and open to the public. Please register by November 7.

The Alaska Ocean Acidification Network is hosting a TWO-day workshop in Anchorage, inviting a broad audience across the state interested in ocean acidification issues.

There will be opportunities for remote participation at satellite viewing sites and via personal computer.

Workshop goals include educating the broader Alaska community on the processes and consequences of OA, creating connections between researchers and stakeholders, and developing new ideas and partnerships to enhance monitoring and community engagement. A report on the state of the science in Alaska will be produced after the workshop, as well as a set of recommendations to help guide the Alaska OA Network.

Continue reading ‘Ocean Acidification “State of the Science” Workshop, 30 November – 1 December 2016, Anchorage, Alaska’


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OA-ICC HIGHLIGHTS

Ocean acidification in the IPCC AR5 WG II

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