October | 2012 | Ocean acidification

Archive for October, 2012

Second International Workshop Bridging the Gap between Ocean Acidification Impacts and Economic Valuation – Ocean acidification impacts on fisheries and aquaculture (in French)

Published 31 October 2012 Meetings , Science Leave a Comment

11-13 novembre 2012, Musée Océanographique de Monaco

Un premier workshop sur les impacts socio-économiques de l’acidification des océans a été organisé à Monaco en novembre 2010 avec l’aide de la Fondation Prince Albert II de Monaco, du Gouvernement Princier, du Ministère Français de l’Écologie, du Musée océanographique – Fondation Prince Albert Ier et du département d’État américain. Ce workshop a regroupé des économistes, des biologistes et des représentants des organisations internationales. Des personnalités emblématiques de la recherche multidisciplinaire étaient présentes, permettant de faciliter les discussions entre ces communautés. Cet événement fut une pleine réussite, ouvrant les débats et les perspectives vers de nouveaux horizons non encore explorés. Des recommandations politiques sont déjà ressorties des discussions, notamment en matière de politique d’atténuation au niveau global et d’adaptation au niveau local.

En 2012, la seconde édition de ce workshop se déroulera du 11 au 13 novembre au Musée Océanographique de Monaco. Cette seconde édition se focalisera sur la pêche et l’aquaculture incluant les aspects régionaux de la vulnérabilité des espèces et l’adaptation socio-économique.

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Second international workshop bridging the gap between ocean acidification impacts and economic valuation – ocean acidification impacts on fisheries and aquaculture

Published 31 October 2012 Meetings , Science Leave a Comment

11-13 November 2012, Oceanographic Museum Monaco

The 1^st International Workshop was organised by the International Atomic Energy Agency and Centre Scientifique de Monaco in association with the Principality of Monaco and the Fondation Prince Albert II de Monaco. It provided an opening venue for natural scientists and economists to introduce their perspectives on the topic of ocean acidification and to build solid linkages between these two communities. The outputs of the meeting were a baseline of scientific and economic information, integration of the language and concepts of dissimilar research methodologies, and publication of conclusions and recommendations concerning the anticipated impacts to ecosystems and ecosystem services from ocean acidification.

The 2^nd International Workshop of the Monaco Environment and Economic Group (MEEG) aims to provide policymakers with recommendations to prepare for social and economic impacts from ocean acidification on livelihoods, trade and food supply from ocean resources.

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Communicating ocean acidification in Bodega Bay

Published 31 October 2012 Science , Web sites and blogs Leave a Comment

What happens to all of the carbon dioxide that is released into the air from our cars and factories?

This is a question that concerns many people these days, particularly scientists like myself that are interested in studying the effects of increased CO₂ on our marine animals. The anthropogenic (caused by humans) input of CO₂ into the atmosphere is causing a series of changes to our environment, including the ocean.

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Occurrences of dissolved trace metals (Cu, Cd, and Mn) in the Pearl River Estuary (China), a large river-groundwater-estuary system

Published 31 October 2012 Science Leave a Comment
Tags: chemistry, field, North Pacific

This study for the first time examined dissolved metals (Cu, Cd, and Mn) together with dissolved oxygen and carbonate system in the whole Pearl River Estuary system, from the upper rivers to the groundwater discharges until the estuarine zone, and explored their potential impacts in the adjacent northern South China Sea (SCS) during May-August 2009. This river-groundwater-estuary system was generally characterized by low dissolved metal levels as a whole, whilst subject to severe perturbations locally. In particular, higher dissolved Cu and Cd occurred in the North River (as high as 60 nmol/L of Cu and 0.99 nmol/L of Cd), as a result of an anthropogenic source from mining activities there. Dissolved Cu levels were elevated in the upper estuary near the city of Guangzhou (Cu: ~40 nmol/L), which could be attributable to sewage and industrial effluent discharges there. Elevated dissolved metal levels (Cu: ‘~20–40 nmol/L; Cd: ~0.2–0.8 nmol/L) also occurred in the groundwaters and parts of the middle and lower estuaries, which could be attributable to a series of geochemical reactions, e.g., chloride-induced desorption from the suspended sediments, oxidation of metal sulfides, and the partial dissolution of minerals. The high river discharge during our sampling period (May-August 2009) significantly diluted anthropogenic signals in the estuarine mixing zone. Of particular note was the high river discharge (which may reach 18.5 times as high as in the dry season) that transported anthropogenic signals (as indicated by dissolved Cu and Cd) into the adjacent shelf waters of the northern SCS, and might have led to the usually high phytoplankton productivity there (chlorophyll a value >10 µg/L).

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Consequences of increased temperature and acidification on bacterioplankton community composition during a mesocosm spring bloom in the Baltic Sea

Published 31 October 2012 Science Leave a Comment
Tags: Baltic Sea, biological response, community composition, field, laboratory, mesocosms, molecular biology, multiple factors, prokaryotes, temperature

Despite the paramount importance of bacteria for biogeochemical cycling of carbon and nutrients, little is known about the potential effects of climate change on these key organisms. The consequences of the projected climate change on bacterioplankton community dynamics were investigated in a Baltic Sea spring phytoplankton bloom mesocosm experiment by increasing temperature with 3°C and decreasing pH by approximately 0.4 units via CO₂ addition in a factorial design. Temperature was the major driver of differences in community composition during the experiment, as shown by denaturing gradient gel electrophoresis (DGGE) of amplified 16S rRNA gene fragments. Several bacterial phylotypes belonging to Betaproteobacteria were predominant at 3°C but were replaced by members of the Bacteriodetes in the 6°C mesocosms. Acidification alone had a limited impact on phylogenetic composition, but when combined with increased temperature, resulted in the proliferation of specific microbial phylotypes. Our results suggest that although temperature is an important driver in structuring bacterioplankton composition, evaluation of the combined effects of temperature and acidification is necessary to fully understand consequences of climate change for marine bacterioplankton, their implications for future spring bloom dynamics, and their role in ecosystem functioning.

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Influence of CO2 and nitrogen limitation on the coccolith volume of Emiliania huxleyi (Haptophyta) (update)

Published 31 October 2012 Science Leave a Comment
Tags: abundance, biogeochemistry, biological response, calcification, growth, laboratory, morphology, multiple factors, nitrogen, ocean acidification, phytoplankton, primary production

Coccolithophores, a key phytoplankton group, are one of the most studied organisms regarding their physiological response to ocean acidification/carbonation. The biogenic production of calcareous coccoliths has made coccolithophores a promising group for paleoceanographic research aiming to reconstruct past environmental conditions. Recently, geochemical and morphological analyses of fossil coccoliths have gained increased interest in regard to changes in seawater carbonate chemistry. The cosmopolitan coccolithophore Emiliania huxleyi (Lohm.) Hay and Mohler was cultured over a range of pCO₂ levels in controlled laboratory experiments under nutrient replete and nitrogen limited conditions. Measurements of photosynthesis and calcification revealed, as previously published, an increase in particulate organic carbon production and a moderate decrease in calcification from ambient to elevated pCO₂. The enhancement in particulate organic carbon production was accompanied by an increase in cell diameter. Changes in coccolith volume were best correlated with the coccosphere/cell diameter and no significant correlation was found between the coccolith volume and the particulate inorganic carbon production. The conducted experiments revealed that the coccolith volume of E. huxleyi is variable with aquatic CO₂ concentration but its sensitivity is rather small in comparison with its sensitivity to nitrogen limitation. Comparing coccolith morphological and geometrical parameters like volume, mass and size to physiological parameters under controlled laboratory conditions is an important step to understand variations in fossil coccolith geometry.

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L’océan tourne à l’aigre (audio; in French)

Published 30 October 2012 Media coverage Leave a Comment

Les océans absorbent chaque année un quart de nos émissions de gaz à effet de serre. Mais depuis le début de la révolution industrielle au 19^e siècle, la production de CO2 s’accélère et les Océans sont au bord de l’indigestion ! Présents sur les trois océans, Indien, Pacifique et Atlantique, les outre-mer sont en première ligne.

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“El exceso de CO2 hará que el mar en el Artico sea corrosivo en 2050” (in Spanish)

Published 30 October 2012 Media coverage Leave a Comment

Jean Pierre Gattusso, uno de los mayores expertos en cambio climático, visitará Chile este lunes para hablar sobre acidificación del mar, un proceso que la era industrial aceleró en los últimos 200 años y que ya está poniendo en peligro a millones de especies, incluido el hombre.

La contaminación generalmente se asocia a las cosas que podemos ver: el esmog, el derretimiento de los hielos, la muerte masiva de especies. Pero también tiene efectos que no siempre se observan a simple vista.

Tal es el caso de la acidificación de los océanos, un proceso que si bien se ha producido naturalmente hace millones de años, hoy vuelve a acecharnos de manera más violenta.

En los últimos 200 años, el nivel de acidificación ha aumentado 30%, el alza más veloz que se ha registrado de manera histórica. Un hecho que preocupa a Jean Pierre Gattusso, oceanógrafo francés que viene a Chile, al seminario “Un desafío frente al cambio climático global”, en la U. Santo Tomás. El experto habló con La Tercera sobre la importancia de estudiar el fenómeno y sobre cómo la contaminación por CO2 no sólo afecta el aire, sino que podría volver al océano un lugar inhóspito y hasta peligroso para las futuras generaciones.

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Age we made (video)

Published 30 October 2012 Media coverage Leave a Comment

Humanity’s impact on the atmosphere with fossil fuel burning is so profound that we’re creating a new geological time period, say geologists. They’ve named it, the Anthropocene.

In this part of her journey into the Anthropocene, Gaia Vince explores how fossil fuel burning will leave enduring marks in geological record forming on the Earth in current times.

Climate change and ocean acidification are in the process of transforming the planet on such a scale that humanity has shifted Earth history into a new geological epoch. Millions of years from now, scientists will be able to read the rocks forming now and see that something profound and unprecedently rapid – from sea level rise to dissolving coral reefs.

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Metabolically active microbial communities in marine sediment under high-CO2 and low-pH extremes

Published 30 October 2012 Science Leave a Comment
Tags: abundance, biological response, diversity, laboratory, molecular biology, North Pacific, physiology, prokaryotes

Sediment-hosting hydrothermal systems in the Okinawa Trough maintain a large amount of liquid, supercritical and hydrate phases of CO₂ in the seabed. The emission of CO₂ may critically impact the geochemical, geophysical and ecological characteristics of the deep-sea sedimentary environment. So far it remains unclear whether microbial communities that have been detected in such high-CO₂ and low-pH habitats are metabolically active, and if so, what the biogeochemical and ecological consequences for the environment are. In this study, RNA-based molecular approaches and radioactive tracer-based respiration rate assays were combined to study the density, diversity and metabolic activity of microbial communities in CO₂-seep sediment at the Yonaguni Knoll IV hydrothermal field of the southern Okinawa Trough. In general, the number of microbes decreased sharply with increasing sediment depth and CO₂ concentration. Phylogenetic analyses of community structure using reverse-transcribed 16S ribosomal RNA showed that the active microbial community became less diverse with increasing sediment depth and CO₂ concentration, indicating that microbial activity and community structure are sensitive to CO₂ venting. Analyses of RNA-based pyrosequences and catalyzed reporter deposition-fluorescence in situ hybridization data revealed that members of the SEEP-SRB2 group within the Deltaproteobacteria and anaerobic methanotrophic archaea (ANME-2a and -2c) were confined to the top seafloor, and active archaea were not detected in deeper sediments (13–30 cm in depth) characterized by high CO₂. Measurement of the potential sulfate reduction rate at pH conditions of 3–9 with and without methane in the headspace indicated that acidophilic sulfate reduction possibly occurs in the presence of methane, even at very low pH of 3. These results suggest that some members of the anaerobic methanotrophs and sulfate reducers can adapt to the CO₂-seep sedimentary environment; however, CO₂ and pH in the deep-sea sediment were found to severely impact the activity and structure of the microbial community.

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