Archive for October, 2014



Escape performance of temperate king scallop, Pecten maximus under ocean warming and acidification

Among bivalves, scallops are exceptional due to their capacity to escape from predators by swimming which is provided by rapid and strong claps that are produced by the phasic muscle interspersed with tonic muscle contractions. Based on the concept of oxygen and capacity-limited thermal tolerance, the following hypothesis was tested: ocean warming and acidification (OWA) would induce disturbances in aerobic metabolic scope and extracellular acid-case status and impair swimming performance in temperate scallops. Following long-term incubation under near-future OWA scenarios [20 vs. 10 °C (control) and 0.112 kPa CO2 (hypercapnia) vs. 0.040 kPa CO2 (normocapnic control)], the clapping performance and metabolic rates (MR) were measured in resting (RMR) and fatigued (maximum MR) king scallops, Pecten maximus, from Roscoff, France. Exposure to OA, either alone or combined with warming, left MR and swimming parameters such as the total number of claps and clapping forces virtually unchanged. Only the duration of the escape response was affected by OA which caused earlier exhaustion in hyper- than in normocapnic scallops at 10 °C. While maximum MR was unaffected, warm exposure increased RMR in both normocapnic and hypercapnic P. maximus resulting in similar Q 10 values of ~2.2. The increased costs of maintenance and the observation of strongly reduced haemolymph PO2 levels indicate that at 20 °C scallops have reached the upper thermal pejus range with unbalanced capacities for aerobic energy metabolism. As a consequence, warming to 20 °C decreased mean phasic force during escape performance until fatigue. The observed prolonged recovery time in warm incubated scallops might be a consequence of elevated metabolic costs at reduced oxygen availability in the warmth.

Continue reading ‘Escape performance of temperate king scallop, Pecten maximus under ocean warming and acidification’

Ocean acidification does not impact shell growth or repair of the Antarctic brachiopod Liothyrella uva (Broderip, 1833)

Marine calcifiers are amongst the most vulnerable organisms to ocean acidification due to reduction in the availability of carbonate ions for skeletal/shell deposition. However, there are limited long-term studies on the possible impacts of increased pCO2 on these taxa. A 7 month CO2 perturbation experiment was performed on one of the most calcium carbonate dependent species, the Antarctic brachiopod Liothyrella uva, which inhabits the Southern Ocean where carbonate ion saturation levels are amongst the lowest on Earth. The effects of the predicted environmental conditions in 2050 and 2100 on the growth rate and ability to repair shell in L. uva were tested with four treatments; a low temperature control (0 °C, pH 7.98), a pH control (2 °C, pH 8.05), mid-century scenario (2 °C, pH 7.75) and end-century scenario (2 °C, pH 7.54). Environmental change impacts on shell repair are rarely studied, but here repair was not affected by either acidified conditions or temperature. Growth rate was also not impacted by low pH. Elevated temperature did, however, increase growth rates. The ability of L. uva to continue, and even increase shell production in warmer and acidified seawater suggests that this species can acclimate to these combined stressors and generate suitable conditions for shell growth at the site of calcification.

Continue reading ‘Ocean acidification does not impact shell growth or repair of the Antarctic brachiopod Liothyrella uva (Broderip, 1833)’

Australian scientists studying the effects of ocean acidification on marine life

Chambers are being set up by Australian scientists under Antarctic sea ice to test the impact of ocean acidification on marine life.

The big acrylic boxes will be fed with seawater enriched with carbon dioxide to show the disruption by acidification that this sea life should expect over the century, according to the Australian Antarctic Division.

Ocean acidification is being caused by the uptake of human-produced excess carbon dioxide into the global seas.

Acidification will cost the world economy more than $US1 trillion annually by 2100 if not curbed, according to a report to the UN Convention on Biological Diversity, released this month.

Widespread effects of acidification, mostly bad, were “nearly inevitable”, the report said.

Continue reading ‘Australian scientists studying the effects of ocean acidification on marine life’

La biodiversité: Sous l’océan, les espèces en danger (audio, in French)

Dernier temps de notre semaine consacrée à la biodiversité.

Ce matin: Cap sur l’océan

Avec nous pour en parler:

Jean-Pierre Gattuso, en duplex depuis Nice, qui est directeur de recherche CNRS au laboratoire d’océanographie de Villefranche. Il a reçu la médaille Blaise Pascal 2013 de l’European Academy of Sciences (EURASC). Il a par ailleurs été élu membre de l’institution.

Philippe Cury, directeur de recherche à l’Institut de recherche pour le développement (IRD) et dirige le Centre de recherche méditerranéenne et tropicale à Sète.

Nell Bennett & Boyan Slat.

Une émission préparée par Tiphaine de Rocquigny

Continue reading ‘La biodiversité: Sous l’océan, les espèces en danger (audio, in French)’

Acidification effects in the behavioural responses of temperate reef fish larvae

Due to anthropogenic activity, atmospheric CO2 levels have been increasing since the last century. Consequently, the average levels of surface pH in the ocean is drastically dropping, affecting marine life, including changes in fish behaviour. In many coastal marine fish the selection of the adult habitat occurs in the pelagic larval phase, relying on hearing and olfaction for orientation as well as for predator avoidance and communication. In the present study, the effects of ocean acidification in the ability of fish larvae to detect olfactory cues from potential predators and auditory cues from adult habitats (reefs) were tested. Larvae of sand-smelt (Atherina presbyter) and painted goby (Pomatoschistus pictus) were reared in a control CO2 treatment (pH~8.10) and in a high CO2 treatment (pH~7.6). Later, fishes were subjected to odour experiments in a two channel choice flume and to sound experiments in an auditory choice chamber. Sand-smelt larvae reared in both control and acidified treatment did not show any response to olfactory cue and to reef sounds. Larval painted goby reared in high CO2 treatment and exposed to olfactory cue, strongly avoided the cue, what did not occur in larvae reared in control CO2 treatment. Regarding to sound tests, painted goby larvae from control treatment discriminated reef noises, as expected, however this behavior was absent in larvae reared in an acidified treatment. This study provid evidence that ocean acidification might affect the sensorial responses (olfactory and auditory) of larvae in some temperate reef fish, with potentially injurious impacts on their survival.

Continue reading ‘Acidification effects in the behavioural responses of temperate reef fish larvae’

Ocean Acidification Forum and Winter Networking Event, 16 December 2014, Portland

Tuesday, Dec. 16, 2014 4:30 p.m. to 7:30 p.m.
Location: Gulf of Maine Research Institute, 350 Commercial St, Portland, Maine

Ocean acidification is changing the chemistry of the ocean and is caused primarily by the buildup of carbon dioxide and reductions in pH and calcium carbonate in its waters. Runoff and river discharges, as well as changes in the climate are contributing to the problem. The Gulf of Maine is particularly susceptible and its bounty of shell-producing resources like lobster, clams, mussels and oysters are at risk. Maine is taking the lead to find solutions and a new state commission is studying ocean acidification and its environmental impact on shellfish and its economic impact on coastal economies. Speakers may include representatives from the Friends of Casco Bay, Gulf of Maine Research Institute, and Maine Ocean Acidification Commission.

The Ocean Acidification Forum runs from 4:30-6:00pm and the E2Tech Winter Networking event will run from 6:00-7:00pm.

Limited space for the forum so register now!

Cost: Forum only: members $15; non-members $30. Forum and networking event: members $25; non-members $40.

Continue reading ‘Ocean Acidification Forum and Winter Networking Event, 16 December 2014, Portland’

Ocean Acidification Workshop in Anchorage, 2 December 2014,

This workshop aims to bring concerned and/or interested individuals together to hear the latest research, policy implications, community perspectives, and potential impacts along Alaska’s coast and oceans.

Location: Anchorage Marriott, 820 W 7th Ave

Time: 9am-4pm; reception to follow from 4-6pm

We know that Alaska is experiencing a rapid and severe onset of OA relative to many other coastal regions. Studies also show that Alaskan coastal communities have varying degrees of vulnerability to OA, ranging from moderate to severe, with the most vulnerable located in regions where fisheries are primary economic drivers of local economies. Partners across the state have taken great strides to implement the current monitoring system in place, but state funding is set to expire in 2015. Now is the pivotal time to engage with a growing number of Alaskans interested in how we can make informed decisions about OA.  We hope that you will be able to join us.

Continue reading ‘Ocean Acidification Workshop in Anchorage, 2 December 2014,’

The Biggest Loser: Shark Edition

Photo by D. Dixson

Photo by D. Dixson

Ocean acidification could be the ultimate weight-loss plan for fish. And that’s not a good thing.

Are you an overweight shark having trouble saying no to second, third, and fourth helpings? Do you stay up late at night slamming squid juice after squid juice? Are you consumed by the constant desire to find, hunt, and devour prey in a way that has haters calling you an “eating machine” behind your back?

Well, do I have the thing for you—it’s called the Ocean Acidification Diet!

This amazing diet has already been proven to work on oysters, clams, coral, and mollusks, as they feel the burn (the burning of their calcium shells away in more acidic seas, that is.) Now new research has found that sharks who used our “secret cleanse formula” for just four days appeared to totally lose their drive to sense and attack prey! (Fine print: Active ingredients are just carbon pollution and seawater. Patent pending.)

Continue reading ‘The Biggest Loser: Shark Edition’

Les océans brûlés (text & audio, in French)

Tempêtes, sécheresses, fonte des glaciers, on pense à tort que les changements climatiques ont des effets essentiellement atmosphériques, mais une catastrophe plus discrète est en cours, préviennent les experts : l’acidification des océans. Un reportage de Chantal Srivastava.

Invités :

Jean-Pierre Gattuso, océanographe au Laboratoire d’océanographie de Villefranche-sur-Mer, en France
Alfonso Mucci, géochimiste et directeur du Département des sciences de la Terre et des planètes de l’Université McGill

Continue reading ‘Les océans brûlés (text & audio, in French)’

Responses of coccolithophores to ocean acidification: a meta-analysis

Concerning their sensitivity to ocean acidification, coccolithophores, a group of calcifying single-celled phytoplankton, are one of the best-studied groups of marine organisms. However, in spite of the large number of studies investigating coccolithophore physiological responses to ocean acidification, uncertainties still remain due to variable and partly contradictory results. In the present study we have used all existing data in a meta-analysis to estimate the effect size of future pCO2 changes on the rates of calcification and photosynthesis and the ratio of particulate inorganic to organic carbon (PIC/POC) in different coccolithophore species. Our results indicate that ocean acidification has a negative effect on calcification and the cellular PIC/POC ratio in the most abundant coccolithophore species Emiliania huxleyi and Gephyrocapsa oceanica. In contrast the more heavily calcified species Coccolithus braarudii did not show a distinct response when exposed to elevated pCO2/reduced pH. Photosynthesis in Gephyrocapsa oceanica was positively affected by high CO2, while no effect was observed for the other coccolithophore species. There was no indication that the method of carbonate chemistry manipulation was responsible for the inconsistent results regarding observed responses in calcification and the PIC/POC ratio. The perturbation method, however, appears to affect photosynthesis, as responses varied significantly between total alkalinity (TA) and dissolved inorganic carbon (DIC) manipulations. These results emphasize that coccolithophore species respond differently to ocean acidification, both in terms of calcification and photosynthesis. Where negative effects occur, they become evident at CO2 levels in the range projected for this century in case of unabated CO2 emissions. As the data sets used in this meta-analysis do not account for adaptive responses and ecological fitness, the questions remains how these physiological responses play out in the natural environment.

Continue reading ‘Responses of coccolithophores to ocean acidification: a meta-analysis’


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Ocean acidification in the IPCC AR5 WG II

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