Posts Tagged 'mitigation'

Climate change and aquaculture: considering adaptation potential

Increases in global population and seafood demand are occurring simultaneously with fisheries decline in an era of rapid climate change. Aquaculture is well positioned to help meet the world’s future seafood needs, but heavy reliance of most global aquaculture on the ambient environment and ecosystem services suggests inherent vulnerability to climate change effects. There are, however, opportunities for adaptation. Engineering and management solutions can reduce exposure to stressors or mitigate stressors through environmental control. Epigenetic adaptation may have the potential to improve stressor tolerance through parental or early life stage exposure. Stressor-resistant traits can be genetically selected for, and maintaining adequate population variability can improve resilience and overall fitness. Information at appropriate time scales is crucial for adaptive response, such as real-time data on stressor levels and/or species’ responses, early warning of deleterious events, or prediction of longer-term change. Diet quality and quantity have the potential to meet increasing energetic and nutritional demands associated with mitigating the effects of abiotic and biotic climate change stressors. Research advancements in understanding how climate change affects aquaculture will benefit most from a combination of empirical studies, modelling approaches, and observations at the farm level. Research to support aquaculture adaptation requires an increasing amount of environmental data to guide biological response studies for regional applications. Increased experimental complexity, resources, and duration will be necessary to better understand the effects of multiple stressors. Ultimately, in order for aquaculture sectors to move beyond short-term coping responses, governance initiatives incorporating the changing needs of stakeholders, users, and culture ecosystems as a whole are required to facilitate planned climate change adaptation and mitigation.

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The application of the seaweeds in neutralizing the “ocean acidification” as a long-term multifaceted challenge

The global effects of ocean acidification (OA) on coral reefs are of growing concern. Carbon dioxide released into the atmosphere as a result of burning fossil fuels, not only has an effect on “global warming”, but also on OA which is called the “other CO2 problem”. OA combined with high ocean temperatures has resulted in a massive bleaching of coral reefs in the Indian Ocean and throughout Southeast Asia over the past decade, which is ultimately lethal. Here we discuss the option if innovative seaweed bio-technology—the Ulva lactuca bioreactor option, with its H+ ion-absorbing capacity and its huge green biomass production of around 50 MT/ha/year—which can stabilize our “World Ocean” and our global coral reefs. From our calculations, we came to the conclusion that an area covered with “Ulva lactuca bioreactors” with a production capacity of 250 × 1016 ha of seaweed per year is needed to remove all H+ ions that cause OA in our “World Ocean” since the beginning of the “Industrial Revolution” ≈ 250 years ago. This is a daunting task and therefore we have opted for a multi-faceted approach including variability in seaweed species, avoidance of eutrophication & heavy-metal accumulation, prevention of global warming by more green-biomass production and a better estimation of the huge Kelp seaweed populations in temperate zones in order to protect our coral reefs for the short term.

Continue reading ‘The application of the seaweeds in neutralizing the “ocean acidification” as a long-term multifaceted challenge’

La terminologie de la géoingénierie marine. Une contribution au projet IATE-CvT (in French)

Pour la première fois mentionnée dans la politique en 1965 par le comité consultatif scientifique du président des États-Unis, la géoingénierie (ou : ingénierie climatique) est une préoccupation relativement nouvelle. Plus de cinquante ans plus tard, le sujet reste néanmoins une topique controversée. La question reste : jusqu’où peut-on intervenir dans le climat afin de contrebalancer le changement climatique d’origine anthropocène ? La géoingénierie fait référence aux techniques développées pour lutter contre le changement climatique en supprimant les gaz à effet de serre de l’atmosphère de l’un côté et de l’autre en augmentant la quantité de lumière solaire réfléchie vers l’espace à partir de la terre et des océans (Shepherd, J. G. 2009). C’est un domaine actuel qui peut éventuellement impliquer chacun sur terre. Le domaine se trouve au cœur de nombreux sommets internationaux (p. ex. le COP21 de 2015 à Paris) et suscite non seulement des questions au niveau de la technologie, mais également au niveau éthique (jusqu’où peut-on altérer la nature ?), politique (protocole de Kyoto, 1997), philosophique (« on est Dieu »), sociologique (les conséquences pour les habitants), biologique (les conséquences pour les espèces) et économique (qui paye ?). Comme la géoingénierie est une préoccupation relativement nouvelle, la terminologie internationale laisse encore à désirer. Le domaine étant en pleine voie de développement, les scientifiques du domaine ne se préoccupent guère avec les mots qu’ils appliquent. Reste la tâche aux terminologues de décrire, nommer et normer les termes. Dans ce travail sont traités dix termes venant de la géoingénierie marine. Les termes ont été rencontrés dans des publications scientifiques anglaises, puis décrits en anglais, français et néerlandais de manière à les intégrer dans les bases de données terminologiques IATE et la base terminologique du Centrum voor Terminologie (CvT ; Centre pour Terminologie).

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Algal communities: an answer to global climate change

Human activities and resultant changes in global climate have profound consequences for ecosystems and economic and social systems, including those that are dependent upon marine systems. The increasing concentration of atmospheric greenhouse gases (GHGs) has resulted in gradual modification of multiple aspects of marine ecosystem properties such as salinity, temperature, and pH. It is well known that temporal and spatial variations in environmental properties determine the composition and abundance of different algal populations in a region. Within the present study the evidence for algal compatibility to changing environmental conditions is surveyed. The unique ability of algal communities to play a role in promotion of CO2 sequestration technologies, biorefinery approaches, as well as transition to CO2‐neutral renewable energy has gained traction with environmentalists and economists in a view to mitigation of climate change using algae. The next step is to re‐evaluate the assumption of a steady‐state oceanic carbon cycle and the role of biological activities in response to future climate changes.

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Increasing seawater alkalinity using fly ash to restore the pH and the effect of temperature on seawater flue gas desulfurization

Wet type flue gas desulfurization (FGD) using lime or limestone is popular because of its operational simplicity and the availability of lime and limestone. Seawater FGD (SWFGD) utilizes the alkalinity of seawater, and its efficiency varies depending on the seawater alkalinity. This study examined the effects of temperature, gas/water ratio, and total alkalinity of the absorbing solution on the removal efficiency of SO2 from flue gas by seawater. In addition, this study showed the possibility of increasing the total alkalinity of seawater using fly ash from coal power plants. The experimental results showed a 8% increase in removal efficiency, while temperature decreased by 10 °C from 25 °C under the conditions of a gas/water ratio of 100 and a resultant pH of 3. The increase in removal efficiency with increasing alkalinity was measured as 0.27%/ppm of bicarbonate alkalinity. This study showed that fly ash has the ability to increase the total alkalinity of seawater. The pH restoration experiment was conducted using fly ash and limestone. The conceptual design processes of SWFGD using NaOH, fly ash, and limestone for a 400 MW coal power plant were developed, and the material balance was calculated using ASPEN Plus software.

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The potential environmental response to increasing ocean alkalinity for negative emissions

The negative emissions technology, artificial ocean alkalinization (AOA), aims to store atmospheric carbon dioxide (CO2) in the ocean by increasing total alkalinity (TA). Calcium carbonate saturation state (ΩCaCO3) and pH would also increase meaning that AOA could alleviate sensitive regions and ecosystems from ocean acidification. However, AOA could raise pH and ΩCaCO3 well above modern-day levels, and very little is known about the environmental and biological impact of this. After treating a red calcifying algae (Corallina spp.) to elevated TA seawater, carbonate production increased by 60% over a control. This has implication for carbon cycling in the past, but also constrains the environmental impact and efficiency of AOA. Carbonate production could reduce the efficiency of CO2 removal. Increasing TA, however, did not significantly influence Corallina spp. primary productivity, respiration, or photophysiology. These results show that AOA may not be intrinsically detrimental for Corallina spp. and that AOA has the potential to lessen the impacts of ocean acidification. However, the experiment tested a single species within a controlled environment to constrain a specific unknown, the rate change of calcification, and additional work is required to understand the impact of AOA on other organisms, whole ecosystems, and the global carbon cycle.

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The ability of macroalgae to mitigate the negative effects of ocean acidification on four species of North Atlantic bivalve (updated)

Coastal ecosystems can experience acidification via upwelling, eutrophication, riverine discharge, and climate change. While the resulting increases in pCO2 can have deleterious effects on calcifying animals, this change in carbonate chemistry may benefit some marine autotrophs. Here, we report on experiments performed with North Atlantic populations of hard clams (Mercenaria mercenaria), eastern oysters (Crassostrea virginica), bay scallops (Argopecten irradians), and blue mussels (Mytilus edulis) grown with and without North Atlantic populations of the green macroalgae, Ulva. In six of seven experiments, exposure to elevated pCO2 levels ( ∼ 1700µatm) resulted in depressed shell- and/or tissue-based growth rates of bivalves compared to control conditions, whereas rates were significantly higher in the presence of Ulva in all experiments. In many cases, the co-exposure to elevated pCO2 levels and Ulva had an antagonistic effect on bivalve growth rates whereby the presence of Ulva under elevated pCO2 levels significantly improved their performance compared to the acidification-only treatment. Saturation states for calcium carbonate (Ω) were significantly higher in the presence of Ulva under both ambient and elevated CO2 delivery rates, and growth rates of bivalves were significantly correlated with Ω in six of seven experiments. Collectively, the results suggest that photosynthesis and/or nitrate assimilation by Ulva increased alkalinity, fostering a carbonate chemistry regime more suitable for optimal growth of calcifying bivalves. This suggests that large natural and/or aquacultured collections of macroalgae in acidified environments could serve as a refuge for calcifying animals that may otherwise be negatively impacted by elevated pCO2 levels and depressed Ω.

Continue reading ‘The ability of macroalgae to mitigate the negative effects of ocean acidification on four species of North Atlantic bivalve (updated)’

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Ocean acidification in the IPCC AR5 WG II

OUP book