Archive for April, 2016

How can education help mitigate ocean acidification?

This May, Hobart, Tasmania will attract more than 350 scientists to an international symposium about our changing climate and ocean, particularly focusing on ocean acidification. Together, NOAA’s Office of National Marine Sanctuaries and Ocean Acidification Program have organized a special outreach session and evening Share-a-Thon to help educators, communicators, and scientists share effective approaches to communicating ocean acidification.

Laura Francis, Channel Islands National Marine Sanctuary education coordinator and an organizer of this special session, explains that “ocean acidification is an emerging issue that could have far-reaching impacts on the health of our national marine sanctuaries and long-term sustainability of ecosystems that support human populations.” With that in mind, she says, “it is critical that educators have access to the latest science information and communication tools on this topic and are able to effectively share the science of ocean acidification, potential impacts, and positive actions with our communities.”

Continue reading ‘How can education help mitigate ocean acidification?’

Pulitzer Prize-winning journalist speaks about risks of ocean acidification

COLUMBIA — Craig Welch said he didn’t exactly know what he was getting himself into when he went fishing with two Papua New Guinea natives in an area that was notorious for sharks.

Trying to break the ice, he said to them: “So, we’re not going to see any sharks, right?” Welch said the two men looked at each other, and said: “Well, when we stab the fish, we’ll try very hard to put them on the boat because when we stab them, they bleed, and that’s what draws the sharks.”

Welch, a former journalist for The Seattle Times and current National Geographic staff writer, spoke to a group of about 70 students, faculty members and community members Wednesday night in Fisher Auditorium about his Pulitzer Prize-winning project about ocean acidification, “Sea Change: The Pacific’s Perilous Turn.” The talk was sponsored by the student group Science, Health & Environmental Journalism.

Welch primarily focused on the struggle of getting people to be interested in ocean acidification, a phenomenon not everyone experiences. Acidification occurs when carbon dioxide is absorbed by seawater, resulting in chemical reactions that cause alterations in seawater pH and other imbalances, according to Pacific Marine Environmental Laboratory.

Continue reading ‘Pulitzer Prize-winning journalist speaks about risks of ocean acidification’

Dinosaur die-off not a result of volcanoes in India: study

Volcanic eruptions in what is now India did not lead to the extinction of the dinosaurs about 65 million years ago, a new study suggests.

Scientists have long argued over the cause of the Cretaceous-Palaeogene extinction event, during which three-quarters of all plant and animal species, including the dinosaurs, went extinct.

Most researchers favour the idea that a catastrophic, sudden mechanism such as an asteroid hit triggered the mass die-off, while others say a gradual rise in carbon dioxide (CO2) emissions from volcanoes in what is now India may have been the cause.

The study demonstrates that Earth’s oceans are capable of absorbing large amounts of carbon dioxide – provided it is released gradually over an extremely long time.

“One way that has been suggested that volcanism could have caused extinction is by ocean acidification, where the ocean absorbs CO2 and becomes more acidic as a result, just as it is doing today with fossil fuel-derived CO2,” said Michael Henehan, a postdoctoral associate at Yale University in US.

Continue reading ‘Dinosaur die-off not a result of volcanoes in India: study’

Characterization model to assess ocean acidification within life cycle assessment

Purpose

Ocean acidification due to the absorption of increasing amounts of atmospheric carbon dioxide has become a severe problem in the recent years as more and more marine species are influenced by the decreasing pH value as well as by the reduced carbonate ion concentration. So far, no characterization model exists for ocean acidification. This paper aims to establish such a characterization model to allow for the necessary future inclusion of ocean acidification in life cycle assessment (LCA) case studies.

Methods

Based on a cause-effect chain for ocean acidification, the substances carbon monoxide, carbon dioxide, and methane were identified as relevant for this impact category. In a next step, the fate factor representing the substances’ share absorbed by the ocean due to conversion, distribution, and dissolution is determined. Then, the fate sensitivity factor is established reflecting the changes in the marine environment due to the amount of released hydrogen ions per gram of substance (category indicator). Finally, fate and fate sensitivity factors of each substance are multiplied and set in relation to the reference substance, carbon dioxide, thereby delivering the respective characterization factors (in kg CO2 eq) at midpoint level.

Results and discussion

Characterization factors are provided for carbon monoxide (0.87 kg CO2 eq), carbon dioxide (1 kg CO2 eq), and methane (0.84 kg CO2 eq), which allow conversion of inventory results of these substances into category indicator results for ocean acidification. Inventory data of these substances is available in common LCA databases and software. Hence, the developed method is directly applicable. In a subsequent contribution analysis, the relative contribution of the three selected substances, along with other known acidifying substances, to the ocean acidification potential of 100 different materials was studied. The contribution analysis confirmed carbon dioxide as the predominant substance responsible for more than 97 % of the total ocean acidification potential. However, the influence of other acidifying substances, e.g., sulfur dioxide, should not be neglected.

Conclusions

Evaluation of substances contributing to ocean acidification is of growing importance since the acidity of oceans has been increasing steadily over the last decades. The introduced approach can be applied to evaluate product system related impacts of ocean acidification and include those into current LCA practice.

Continue reading ‘Characterization model to assess ocean acidification within life cycle assessment’

Ocean acidification addressed at the Benguela Symposium 2016, Cape Town , South Africa, 15-18 November 2016

Session 1 – Upwelling systems as natural laboratories for global change: Environmental conditions

Upwelling systems could serve as natural laboratories for studies on the effects of these stressors. The current or natural environmental conditions in the Benguela system (and other coastal upwelling systems) with regard to ocean acidification, ocean deoxygenation (hypoxia), and eutrophication already now exceed most of the future scenarios predicted for other parts of the world ocean under global change. What we learn from events in the Benguela and how remotely-driven environmental changes affect organisms and interactions between them, can provide insight into links between biotic and abiotic elements.

Further information.

Microphytobenthic community composition and primary production at gas and thermal vents in the Aeolian Islands (Tyrrhenian Sea, Italy)

Sediment samplings were performed to investigate the microphytobenthic community and photosynthetic activity adaptations to gas emissions and higher temperature in the Aeolian Islands during a three-year period (2012–2014). Higher microphytobenthic densities were recorded at the vent stations and values were even more pronounced in relation with high temperature. The gross primary production estimates strongly depended on microphytobenthic abundance values reaching up to 45.79 ± 6.14 mgC m−2 h−1. High abundances were coupled with low community richness and diversity. Motile diatom living forms were predominant at all stations and the greatest differences among vent and reference stations were detected on the account of the tychopelagic forms. Morphological deformities and heavily silicified diatom frustules were also observed. A significant influence of the gas emission and high temperature on the phototrophic community was highlighted suggesting the Aeolian Islands as a good natural laboratory for studies on high CO2 and global warming effects.

Continue reading ‘Microphytobenthic community composition and primary production at gas and thermal vents in the Aeolian Islands (Tyrrhenian Sea, Italy)’

Changes in soft coral Sarcophyton sp. abundance and cytotoxicity at volcanic CO2 seeps in Indonesia

This study presents the relationship between benthic cover of Sarcophyton sp. living on coral reefs and their cytotoxicity (an assumption of soft coral allelochemical levels) along acidification gradients caused by shallow water volcanic vent systems. Stations with moderate acidification (pH 7.87 ± 0.04), low acidification (pH 8.01 ± 0.04), and reference conditions (pH 8.2 ± 0.02) were selected near an Indonesian CO2 seep (Minahasa, Gunung Api Island, and Mahengetang Island). Cover of the dominant soft coral species (Sarcophyton sp.) was assessed and tissue samples were collected at each site. The cytotoxicity tissue extracts were analyzed using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolinon bromide (MTT) method. Levels of cytotoxicity were strongly correlated with Sarcophyton sp. cover (p < 0.05; R2 = 0.60 at 30 ppm and 0.56 at 100 ppm), being highest at mean pH 8.01 where the soft corals were most abundant. This finding suggests that Sarcophyton sp. can be expected to survive ocean acidification near Indonesia in the coming decades. How the species might be adversely affected by further ocean acidification later in the century unless CO2 emissions are reduced remains a concern.

Continue reading ‘Changes in soft coral Sarcophyton sp. abundance and cytotoxicity at volcanic CO2 seeps in Indonesia’

Pacific islands ocean acidification vulnerability assessment

The Pacific island region covers an area of more than 27 million km2 and is dominated by ocean. The 22 Pacific island countries and territories are mostly small island states with significant geological, biological, and social diversity. Unsurprisingly, Pacific island people have a high dependence on their ocean resources for food security, livelihoods, and economic revenue, as well as cultural connections to marine environments and animals.

Throughout the tropical Pacific, fisheries and aquaculture make vital contributions to economic development, government revenue, food security, and livelihoods. Climate change, and ocean
acidification, are expected to have profound effects on the status and distribution of coastal and oceanic habitats, the fish and invertebrates they support and, as a result, the productivity of fisheries and aquaculture.

Continue reading ‘Pacific islands ocean acidification vulnerability assessment’

Dinosaur die-off not a result of volcanoes, study says

A new study suggests that volcanic eruptions did not lead to the extinction of the dinosaurs, and also demonstrates that Earth’s oceans are capable of absorbing large amounts of carbon dioxide — provided it is released gradually over an extremely long time.

Scientists have long argued over the cause of the Cretaceous-Palaeogene extinction event, during which three-quarters of all plant and animal species, including the dinosaurs, went extinct roughly 65 million years ago. Most researchers favor the idea that a catastrophic, sudden mechanism such as an asteroid hit triggered the mass die-off, while others say a gradual rise in CO2 emissions from volcanoes in what is now India may have been the cause.

Scientists at Yale and in the United Kingdom say they may have a more definitive answer.

“One way that has been suggested that volcanism could have caused extinction is by ocean acidification, where the ocean absorbs CO2 and becomes more acidic as a result, just as it is doing today with fossil fuel-derived CO2,” said Michael Henehan, a postdoctoral associate at Yale and lead author of a study appearing April 25 in the journal Philosophical Transactions of the Royal Society B.

Continue reading ‘Dinosaur die-off not a result of volcanoes, study says’

Biogeochemical significance of pelagic ecosystem function: an end-Cretaceous case study

Pelagic ecosystem function is integral to global biogeochemical cycling, and plays a major role in modulating atmospheric CO2 concentrations (pCO2). Uncertainty as to the effects of human activities on marine ecosystem function hinders projection of future atmospheric pCO2. To this end, events in the geological past can provide informative case studies in the response of ecosystem function to environmental and ecological changes. Around the Cretaceous–Palaeogene (K–Pg) boundary, two such events occurred: Deccan large igneous province (LIP) eruptions and massive bolide impact at the Yucatan Peninsula. Both perturbed the environment, but only the impact coincided with marine mass extinction. As such, we use these events to directly contrast the response of marine biogeochemical cycling to environmental perturbation with and without changes in global species richness. We measure this biogeochemical response using records of deep-sea carbonate preservation. We find that Late Cretaceous Deccan volcanism prompted transient deep-sea carbonate dissolution of a larger magnitude and timescale than predicted by geochemical models. Even so, the effect of volcanism on carbonate preservation was slight compared with bolide impact. Empirical records and geochemical models support a pronounced increase in carbonate saturation state for more than 500 000 years following the mass extinction of pelagic carbonate producers at the K–Pg boundary. These examples highlight the importance of pelagic ecosystems in moderating climate and ocean chemistry.

Continue reading ‘Biogeochemical significance of pelagic ecosystem function: an end-Cretaceous case study’


Subscribe to the RSS feed

Powered by FeedBurner

Follow AnneMarin on Twitter

Blog Stats

  • 1,400,684 hits

OA-ICC HIGHLIGHTS

Ocean acidification in the IPCC AR5 WG II

OUP book

Archives