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Israeli study: corals can live, breed in climate change

Bar-Ilan University’s Jessica Bellworthy monitoring coral health. Photo by M. Kahana

Parent corals from the Red Sea have the same reproductive output even when experiencing increased temperatures and ocean acidification stress.

The fact that climate change poses a threat to coral reefs is bad if somewhat old news. The good new news, however, is that an exception to that rule seems to be taking place in the Red Sea to Israel’s south.

Researchers have found that corals from the Gulf of Aqaba (where the southern Israeli city of Eilat is located) are not only surviving the effects of global warming, but are producing healthy offspring.

Continue reading ‘Israeli study: corals can live, breed in climate change’

Ecological and physiological constraints of deep-sea corals in a changing environment

Deep-water or cold-water corals are abundant and highly diverse, greatly increase habitat heterogeneity and species richness, thereby forming one of the most significant ecosystems in the deep sea. Despite this remote location, they are not removed from the different anthropogenic disturbances that commonly impact their shallow-water counterparts. The global decrease in seawater pH due to increases in atmospheric CO2 are changing the chemical properties of the seawater, decreasing the concentration of carbonate ions that are important elements for different physiological and ecological processes. Predictive models forecast a shoaling of the carbonate saturation in the water column due to OA, and suggest that cold-water corals are at high risk, since large areas of suitable habitat will experience suboptimal conditions by the end of the century. The main objective of this study was to explore the fate of the deep-water coral community in time of environmental change. To better understand the impact of climate change this study focused in two of the most important elements of dee-sea coral habitat, the reef forming coral Lophelia pertusa and the octocoral community, particularly the gorgonian Callogorgia delta. By means of controlled experiments, I examined the effects of long and short-term exposures to seawater simulating future scenarios of ocean acidification on calcification and feeding efficiency. Finally In order to understand how the environment influences the community assembly, and ultimately how species cope with particular ecological filters, I integrated different aspects of biology such functional diversity and ecology into a more evolutionary context in the face of changing environment. My results suggest that I) deep-water corals responds negatively to future OA by lowering the calcification rates, II) not all individuals respond in the same way to OA with high intra-specific variability providing a potential for adaptation in the longterm III) there is a disruption in the balance between accretion and dissolution that in the long term can shift from net accretion to net dissolution, and IV) there is an evolutionary implication for certain morphological features in the coral community that can give an advantage under stresfull conditions. Nevertheless, the suboptimal conditions that deepwater corals will experience by the end of the century could potentially threaten their persistence, with potentially negative consequences for the future stability of this already fragile ecosystem.

Continue reading ‘Ecological and physiological constraints of deep-sea corals in a changing environment’

Ocean acidification, climate change, and you: a Casco Bay matters event

Event organizer: Jeff Fetterer

Event Date & Time: March 25, 2019 5:30 pm until March 25, 2019 6:30 pm

Contact email: keeper@cascobay.org

For more information: https://www.cascobay.org/casco-bay-matters/

Location: Southern Maine Community College, Fort Road, South Portland, ME, USA

We are seeing the impacts of climate change in our coastal waters. Friends of Casco Bay invites you to “Ocean Acidification, Climate Change, and You,” three community events. Staff scientist Mike Doan will talk about the warning signs we see in our monitoring data. Casco Baykeeper Ivy Frignoca will inspire the audience to help us respond to these threats to Maine’s coastal environment and marine economy. Learn more. https://www.cascobay.org/casco-bay-matters/

This is such an important issue that we will offer this presentation at three locations around the Bay in the coming weeks. Come to the event nearest to you, or all three! Free and open to the public.

Continue reading ‘Ocean acidification, climate change, and you: a Casco Bay matters event’

Commonwealth ocean acidification action group meeting in Dunedin

New Zealand leading Commonwealth into fight against ocean acidification Major steps to harness the collective power of the Commonwealth in the fight against ocean acidification will take place at the University of Otago, Dunedin in mid-February.

The Commonwealth Ocean Acidification Action Group Workshop will bring approximately 45 international experts and Commonwealth marine policy and science officials together to share knowledge and experience to better understand and address the impacts of ocean acidification.

Dr Christina McGraw of Otago’s Department of Chemistry, and Chair of the NZOAC Council, says the drop in pH of our oceans (or ‘ocean acidification’) in a relatively short historical timeframe makes the issue one of the most significant influencers of ocean health today.

“Ocean Acidification is something that is happening now. We can’t stop it until we reduce carbon emissions, but we can start thinking about ways to plan and mitigate for it. The more people we have thinking about it now, the more ideas that can be generated towards the issue,” Dr McGraw says.

Continue reading ‘Commonwealth ocean acidification action group meeting in Dunedin’

Context-dependence of abiotic and biotic factors influencing performance of juvenile clams

Highlights

• We found site-level variability in performance of two sizes of juvenile Manila clams.

• Field experiments concurrently assessed the roles of biotic and abiotic variables.

• Performance was particularly impaired at one site with hot summer porewater temperatures.

• Under greater abiotic stress, smaller clams suffered more losses than large.

• Salinity, elevation, and pH were less important to survival than was predator density.

Abstract

Post-settlement survival and growth of bivalves can be limited by abiotic and biotic factors, both of which are spatially variable. Rarely has the importance of these factors been tested concurrently in the field. Our study spanned three spatial scales in estuarine waters of Washington state (Region: north vs. south; Within-region: fresher vs. saline; Within-site: mid- vs. low-tidal elevation). Predator access and sediment conditions were manipulated in a crossed experimental design, with juvenile (3-mm and 6-mm) Manila clams (Ruditapes philippinarum) outplanted in open- or closed-top mesh tubes. We found differences between treatments that appeared only at sites with cancrid crabs, suggesting that predators, rather than emigration, likely reduced numbers of clams in open tubes. We had hypothesized that clams at lower tidal elevations, which experience longer immersion times, would show improved growth but reduced survivorship because of greater exposure to marine predators. However, these patterns were evident at only one of three sites (lower-elevation treatments were lost at the fourth). The larger size class of clams was more tolerant of abiotic stressors at all sites, but the magnitude of difference in survival between size classes was sometimes dependent on other treatments. The maximum predator effect on survival was 74% (north, high salinity, low-intertidal site), whereas the maximum abiotic effect appeared as 62% lower survival and 59% slower growth for 3-mm clams at another site (north, fresher). In laboratory trials, high water temperatures (28–32 °C) and low salinity (5–15) acted synergistically to cause juvenile clam (6–12 mm) mortality, whereas clams tolerated each of these stressors alone. Context-dependence in the relative importance of predation and abiotic stressors was apparent in our results, but contrary to expectations, abiotic stressors did not characterize southern or fresher sites. Instead, extreme high temperatures occurred at the site with the wide tidal flat rather than in the south, and the within-region salinity differences appeared not to exceed tolerances of juvenile clams.

Continue reading ‘Context-dependence of abiotic and biotic factors influencing performance of juvenile clams’

The influence of simulated global ocean acidification on the toxic effects of carbon nanoparticles on polychaetes

Highlights

• Slighter aggregation and more suspended carbon nanomaterials in acidified seawater

• Under pH acidified both carbon nanomaterials generated greater oxidative stress in polychaetes.

• Functionalized carbon nanomaterials increased oxidative stress and neurotoxicity under both pHs.

• Ocean acidification may cause a higher risk of carbon nanomaterials to marine ecosystems.

Abstract

Ocean acidification events are recognized as important drivers of change in biological systems. Particularlly, the impacts of estuarine acidification are severe than surface ocean due to its shallowness, low buffering capacity, low salinity and high organic matter from land drainage. Moreover, because they are transitional areas, estuaries can be seriously impacted by any number of anthropogenic activities and in the last decades, carbon nanomaterials (CNMs) are considered as emerging contaminants in the estuarine ecosystem. Considering all these evidences, chronic experiment was carried out trying to understand the possible alteration on the chemical behaviour of two different CNMs (functionalized and pristine) in predicted climate change scenarios and consequently, how these alterations could modify the sensitivity of one the most common marine and estuarine organisms (the polychaeta Hediste diversicolor) assessing a set of biomarkers related to polychaetes oxidative status as well as the metabolic performance and neurotoxicity. Our results demonstrated that all enzymes worked together to counteract seawater acidification and CNMs, however oxidative stress in the exposed polychaetes to both CNMs, especially under ocean acidification conditions was enhanced. In fact, although the antioxidant enzymes tried to cope as compensatory response of cellular defense systems against oxidative stress, the synergistic interactive effects of pH and functionalized CNMs indicated that acidified pH significantly increased the oxidative damage (in terms of lipid peroxidation) in the cotaminated organisms. Different responses were observed in organisms submitted to pristine CNMs under pH control, where the lipid peroxidation did not increase along with the increasing exposure concentrations. The present results further demonstrated the neurotoxicity caused by both CNMs, especially noticeable at acidified conditions. The mechanism of enhanced toxicity could be attributed to slighter aggregation and more suspended NMs in acidified seawater (demonstrated in the DLS analysis). Therefore, ocean acidification may cause a higher risk of CNMs to marine ecosystems.

Continue reading ‘The influence of simulated global ocean acidification on the toxic effects of carbon nanoparticles on polychaetes’

‘Underwater forecast’ predicts temperature, acidity and more in Puget Sound

Most of us rely on the weather forecast to choose our outfit or make outdoor plans for the weekend. But conditions underwater can also be useful to know in advance, especially if you’re an oyster farmer, a fisher or even a recreational diver.

A new University of Washington computer model can predict conditions in Puget Sound and off the coast of Washington three days into the future. LiveOcean, completed this past summer, uses marine currents, river discharges and weather above the water to create the forecasts.

“It’s like a weather forecast of the ocean in our region,” said lead developer Parker MacCready, a UW professor of oceanography. The project is the culmination of about 15 years of work. “It started off small, modeling parts of Puget Sound, and went to modeling the Columbia River and the coastal ocean nearby, to modeling the whole region. We’re making the model bigger and more realistic all the time.”

Continue reading ‘‘Underwater forecast’ predicts temperature, acidity and more in Puget Sound’


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OA-ICC HIGHLIGHTS

Ocean acidification in the IPCC AR5 WG II

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