Archive for August, 2012

« Previous Entries
Next Entries »

Full report: ocean acidification (report and video)

Published 17 August 2012 Newsletters and reports , Science Closed

Increasing atmospheric CO2 concentration is causing increased absorption of CO2 by the world’s oceans, in turn driving a decline in seawater pH and changes in ocean carbonate chemistry that are collectively referred to as ocean acidification. Evidence is accumulating to suggest ocean acidification may directly or indirectly affect many marine organisms and ecosystems, some of which may also hold significant social and economic value to the Australian community.
This report card aims to provide a brief overview of the current state of scientific knowledge regarding the process of ocean acidification; current and future projected levels of ocean acidification; and, observed and projected impacts of current and future predicted levels of ocean acidification on marine organisms and ecosystems in the region. This Report Card also briefly discusses potential social and economic implications, policy challenges, and the key knowledge gaps needing to be addressed.

Continue reading ‘Full report: ocean acidification (report and video)’

Marine climate change in Australia – 2012 report card

Published 17 August 2012 Newsletters and reports , Science Closed

This 2012 Report Card demonstrates that climate change is having significant impacts on Australia’s oceans and marine ecosystems.

Many new changes have been documented since the 2009 Report Card. There is now striking evidence of extensive southward movements of tropical fish and plankton species in southeast Australia, declines in abundance of temperate species, and the first signs of the effect of ocean acidification on marine species with shells.

Continue reading ‘Marine climate change in Australia – 2012 report card’

Extinctions in ancient and modern seas

Published 16 August 2012 Science Closed
Tags: ,

In the coming century, life in the ocean will be confronted with a suite of environmental conditions that have no analog in human history. Thus, there is an urgent need to determine which marine species will adapt and which will go extinct. Here, we review the growing literature on marine extinctions and extinction risk in the fossil, historical, and modern records to compare the patterns, drivers, and biological correlates of marine extinctions at different times in the past. Characterized by markedly different environmental states, some past periods share common features with predicted future scenarios. We highlight how the different records can be integrated to better understand and predict the impact of current and projected future environmental changes on extinction risk in the ocean.

Continue reading ‘Extinctions in ancient and modern seas’

“Ocean conservation: pearls of wisdom” on ocean acidification (audio)

Published 16 August 2012 Media coverage Closed

Ocean pollution is something most of us are well aware of whether it be from seeing plastic bags washed ashore or images of marine life stuck in oil spills – but ocean acidification is a more latent phenomenon that scientists are still learning about. This week on Sea Change Radio, host Alex Wise speaks first with the editor of E: The Environmental magazine, Brita Belli, about her recent feature on ocean acidification and how oysters have been an unlikely source for better understanding the problem – and possible solutions. Then, the second part of our discussion with Seth Berry, an Assemblyman from Maine who’s not only actively involved in local environmental political issues, he also helps run a sustainable aquaculture business.

Continue reading ‘“Ocean conservation: pearls of wisdom” on ocean acidification (audio)’

First go the shellfish

Published 16 August 2012 Media coverage Closed

Clams are among the shellfish suffering thinning shells due to ocean acidification.

Ocean acidification continues to alarm scientists, as new evidence emerges about the impacts on shellfish, a vital part of the food chain for both marine animals and people.

A broad survey, spanning from the tropics to the poles, found thinning shells among a variety of shellfish including clams, sea snails and sea urchins. Researchers from British Antarctic Survey, the National Oceanography Centre, Australia’s James Cook and Melbourne Universities, and the National University of Singapore collaborated to investigate the impacts of ocean acidification in 12 regions. The results were published August 5 in the journal Global Change Biology.

Continue reading ‘First go the shellfish’

Natural Resources Defense Council (NRDC), science fellow job announcement

Published 16 August 2012 Jobs , Science Closed

The Natural Resources Defense Council (NRDC), a national nonprofit conservation organization, has an opening beginning in September 2012 for a two-year, full-time Science Fellow. The Fellow will be supported by NRDC’s Science Center, whose mission is to expand NRDC’s scientific capabilities and increase support for the role of science in public policy, and will work with NRDC’s Oceans Program and several academic scientists on a spatial analysis identifying ocean acidification ‘hotspots’ in the U.S. and globally.

Continue reading ‘Natural Resources Defense Council (NRDC), science fellow job announcement’

CO2-driven ocean acidification alters and weakens integrity of the calcareous tubes produced by the serpulid tubeworm, Hydroides elegans

Published 15 August 2012 Science Closed
Tags: , , , ,

As a consequence of anthropogenic CO2-driven ocean acidification (OA), coastal waters are becoming increasingly challenging for calcifiers due to reductions in saturation states of calcium carbonate (CaCO3) minerals. The response of calcification rate is one of the most frequently investigated symptoms of OA. However, OA may also result in poor quality calcareous products through impaired calcification processes despite there being no observed change in calcification rate. The mineralogy and ultrastructure of the calcareous products under OA conditions may be altered, resulting in changes to the mechanical properties of calcified structures. Here, the warm water biofouling tubeworm, Hydroides elegans, was reared from larva to early juvenile stage at the aragonite saturation state (ΩA) for the current pCO2 level (ambient) and those predicted for the years 2050, 2100 and 2300. Composition, ultrastructure and mechanical strength of the calcareous tubes produced by those early juvenile tubeworms were examined using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and nanoindentation. Juvenile tubes were composed primarily of the highly soluble CaCO3 mineral form, aragonite. Tubes produced in seawater with aragonite saturation states near or below one had significantly higher proportions of the crystalline precursor, amorphous calcium carbonate (ACC) and the calcite/aragonite ratio dramatically increased. These alterations in tube mineralogy resulted in a holistic deterioration of the tube hardness and elasticity. Thus, in conditions where ΩA is near or below one, the aragonite-producing juvenile tubeworms may no longer be able to maintain the integrity of their calcification products, and may result in reduced survivorship due to the weakened tube protection.

Continue reading ‘CO2-driven ocean acidification alters and weakens integrity of the calcareous tubes produced by the serpulid tubeworm, Hydroides elegans’

Oxygen and indicators of stress for marine life in multi-model global warming projections

Published 14 August 2012 Science Closed
Tags: , ,

Decadal-to-century scale trends for a range of marine environmental variables are investigated using results from seven Earth System Models forced by a high greenhouse gas emission scenario. The models as a class represent the observation-based distribution of the fugacity of oxygen (fO2) and carbon dioxide (fCO2), and the logarithm of their ratio, i.e. the Respiration Index (RI), albeit major mismatches between observation-based and simulated values remain for individual models. All models project an increase in SST between 2 °C and 3 °C by year 2100, a decrease in upper ocean pH and in the saturation state of water with respect to calcium carbonate minerals, and a decrease in the total ocean inventory of dissolved oxygen by 2% to 4%. Projected fO2 changes in the thermocline show a complex pattern with both increasing and decreasing trends reflecting the subtle balance of different competing factors such as circulation, production, remineralisation, and temperature changes. Projected changes in the total volume of hypoxic and suboxic waters remain relatively small in all models. A widespread increase of fCO2 in the thermocline is projected. The median of the thermocline fCO2 distribution shifts from 350 μatm in year 1990 to 700–800 μatm in year 2100, primarily as a result of the invasion of anthropogenic carbon from the atmosphere and is responsible for the widespread decrease in the RI outside low oxygen regions. The co-occurrence of changes in a range of environmental variables indicates the need to further investigate their synergistic impacts on marine ecosystems and Earth System feedbacks.

Continue reading ‘Oxygen and indicators of stress for marine life in multi-model global warming projections’

Limacina retroversa’s response to combined effects of ocean acidification and sea water freshening

Published 14 August 2012 Science Closed
Tags: , , , , , , , , , ,

Anthropogenic carbon dioxide emissions induce ocean acidification, thereby reducing carbonate ion concentration, which may affect the ability of calcifying organisms to build shells. Pteropods, the main planktonic producers of aragonite in the worlds’ oceans, may be particularly vulnerable to changes in sea water chemistry. The negative effects are expected to be most severe at high-latitudes, where natural carbonate ion concentrations are low. In this study we investigated the combined effects of ocean acidification and freshening on Limacina retroversa, the dominant pteropod in sub polar areas. Living L.retroversa, collected in Northern Norwegian Sea, were exposed to four different pH values ranging from the pre-industrial level to the forecasted end of century ocean acidification scenario. Since over the past half-century the Norwegian Sea has experienced a progressive freshening with time, each pH level was combined with a salinity gradient in two factorial, randomized experiments investigating shell degradation, swimming behavior and survival. In addition, to investigate shell degradation without any physiologic influence, one perturbation experiments using only shells of dead pteropods was performed.

Lower pH reduced shell mass whereas shell dissolution increased with pCO2. Interestingly, shells of dead organisms had a higher degree of dissolution than shells of living individuals. Mortality of Limacina retroversa was strongly affected only when both pH and salinity reduced simultaneously. The combined effects of lower salinity and lower pH also affected negatively the ability of pteropods to swim upwards. Results suggest that the energy cost of maintaining ion balance and avoiding sinking (in low salinity scenario) combined with the extra energy cost necessary to counteract shell dissolution (in high pCO2 scenario), exceed the available energy budget of this organism causing the pteropods to change swimming behavior and begin to collapse. Since L.retroversa play an important role in the transport of carbonates to the deep oceans these findings have significant implications for the mechanisms influencing the inorganic carbon cycle in the sub-polar area.

Continue reading ‘Limacina retroversa’s response to combined effects of ocean acidification and sea water freshening’

Short-term and seasonal pH, pCO2 and saturation state variability in a coral-reef ecosystem

Published 14 August 2012 Science Closed
Tags: , , ,

Coral reefs are predicted to be one of the ecosystems most sensitive to ocean acidification. To improve predictions of coral reef response to acidification, we need to better characterize the natural range of variability of pH, partial pressure of carbon dioxide (pCO2) and calcium carbonate saturation states (Ω). In this study, autonomous sensors for pH and pCO2 were deployed on Media Luna reef, Puerto Rico over three seasons from 2007 to 2008. High temporal resolution CaCO3 saturation states were calculated from the in situ data, giving a much more detailed characterization of reef saturation states than previously possible. Reef pH, pCO2 and aragonite saturation (ΩAr) ranged from 7.89 to 8.17 pH units, 176–613 μatm and 2.7–4.7, respectively, in the range characteristic of most other previously studied reef ecosystems. The diel pH, pCO2 and Ω cycles were also large, encompassing about half of the seasonal range of variability. Warming explained about 50% of the seasonal supersaturation in mean pCO2, with the remaining supersaturation primarily due to net heterotrophy and net CaCO3 production. Net heterotrophy was likely driven by remineralization of mangrove derived organic carbon which continued into the fall, sustaining high pCO2 levels until early winter when the pCO2 returned to offshore values. As a consequence, the reef was a source of CO2 to the atmosphere during the summer and fall and a sink during winter, resulting in a net annual source of 0.73 ± 1.7 mol m−2 year−1. These results show that reefs are exposed to a wide range of saturation states in their natural environment. Mean ΩAr levels will drop to 3.0 when atmospheric CO2 increases to 500 μatm and ΩAr will be less than 3.0 for greater than 70% of the time in the summer. Long duration exposure to these low ΩAr levels are expected to significantly decrease calcification rates on the reef.

Continue reading ‘Short-term and seasonal pH, pCO2 and saturation state variability in a coral-reef ecosystem’

Studying ocean acidification and its effects on marine ecosystems

Published 14 August 2012 Courses and training , Science Closed

Short Course: December 4- 6, 2012

Recent studies have demonstrated that increased concentrations of carbon dioxide (CO2) in the oceans pose significant risks to marine organisms. This short course will introduce participants to the basics of CO2-system chemistry in seawater and its measurement, as well as how to design experiments to measure the impacts of ocean acidification on marine organisms. Emphasis will be on providing participants with the resources and training to jump-start their own research on ocean acidification research while avoiding some common mistakes.

Continue reading ‘Studying ocean acidification and its effects on marine ecosystems’

Carbon cycling and its effect on oxygen concentrations and pH in a seasonally anoxic coastal marine system

Published 14 August 2012 Science Closed

Coastal systems are increasingly experiencing low-oxygen conditions, due to enhanced primary production from terrestrial nutrient input and increasing thermal stratification as a result of global warming. The second effect of increased atmospheric CO2 is an enhanced uptake by surface oceans, thereby lowering the pH. Organic carbon cycling is one of the key processes that links oxygen and pH in coastal systems, as oxygen is produced and protons are consumed by photosynthesis, while oxic remineralization in deeper water has the reverse effect. The question arises how extended periods of water-column hypoxia affect the pH of the system. Lake Grevelingen, in the southwestern part of the Netherlands, was used as a case study, as this lake has seasonal periods of hypoxia that vary in extent between consecutive years. On monthly cruises in 2012 water-column data were collected using CTD measurements and DOC and nutrient analyses on samples from discrete water depths. Suspended matter was filtered from water samples and analyzed for organic carbon and total nitrogen content. Field data were combined with a newly constructed 1D-reactive transport model of the carbon cycling, which used data from Rijkswaterstaat as forcing and calibration data. pH and oxygen concentration were calculated in the model as dependent variables. Measurements of pH in Lake Grevelingen show a decline over the past 30 years with ~0.005 unit per year, which coincided with ~0.07 μg L-1 yr-1 increase in chlorophyll a. The modeled gross primary production was within the range reported in the literature, but well below the preliminary estimate for 2012. Deep-water pH in the model is only dependent on oxic mineralization, which has led to lower values than those observed in the water column. In years of more extensive hypoxia, the drop in pH was larger than during the years of shorter hypoxic periods. Anaerobic processes may enhance the buffer factor of the system, thereby mitigating the respiratory decline in pH. An assessment of the buffer factor of Lake Grevelingen showed that the system is more vulnerable to changes in pH due to uptake of atmospheric CO2 than the Eastern China Sea and the Gulf of Mexico.

Continue reading ‘Carbon cycling and its effect on oxygen concentrations and pH in a seasonally anoxic coastal marine system’

BIOACID extended for a second 3-year funding period

Published 14 August 2012 Projects , Science Closed

BIOACID (Biological Impacts of Ocean Acidification), the German national project on ocean acidification, has been extended for a second 3-year phase starting on September 1st 2012. Building on the knowledge gained during phase 1, BIOACID II will aim at community level responses to ocean acidification, their ecosystem and biogeochemical consequences and socio-economic impacts.

Continue reading ‘BIOACID extended for a second 3-year funding period’

CO2 sous surveillance (video; in French)

Published 14 August 2012 Media coverage Closed

Les scientifiques travaillent sur la base de Stareso en Haute Corse pour comprendre les effets du CO2 sur le milieu marin.

Continue reading ‘CO2 sous surveillance (video; in French)’

Mission scientifique en mer au large de Calvi (video; in French)

Published 14 August 2012 Media coverage Closed

Sur la base de Stareso à Calvi des chercheurs français et étrangers étudient un phénomène qui touche toutes les mers du globe: Avec l’augmentation du gaz carbonique dans l’atmosphère, l’eau est en train de s’acidifier.

Continue reading ‘Mission scientifique en mer au large de Calvi (video; in French)’

Bigelow gets federal grants totaling more than $1M

Published 14 August 2012 Media coverage Closed

PORTLAND, Maine (AP) — Sens. Olympia Snowe and Susan Collins of Maine say federal grants totaling more than $1 million are being awarded to the Bigelow Laboratory for Ocean Sciences.

They say a grant of nearly $1 million will go toward construction of a new facility focusing on ocean acidification. A second grant of about $150,000 will help fund a study of the ecosystem within the earth’s crust underneath the ocean floor.

Continue reading ‘Bigelow gets federal grants totaling more than $1M’

Lowering pH levels killing Washington shellfish (text and audio)

Published 14 August 2012 Media coverage Closed

OLYMPIA, Wash.– Washington’s shellfish are dying and it has nothing to do with pollution.

The State Department of Ecology is discovering that increased deaths in juvenile shellfish larvae are due to growing acidity in the waters.

Hedia Adelsman, project manager with the Governor’s Blue Ribbon Panel on Ocean Acidification says this is a problem that hasn’t really been addressed in the past.

Continue reading ‘Lowering pH levels killing Washington shellfish (text and audio)’

Ocean acidification in a geoengineering context

Published 13 August 2012 Science Closed
Tags: ,

Fundamental changes to marine chemistry are occurring because of increasing carbon dioxide (CO2) in the atmosphere. Ocean acidity (H+ concentration) and bicarbonate ion concentrations are increasing, whereas carbonate ion concentrations are decreasing. There has already been an average pH decrease of 0.1 in the upper ocean, and continued unconstrained carbon emissions would further reduce average upper ocean pH by approximately 0.3 by 2100. Laboratory experiments, observations and projections indicate that such ocean acidification may have ecological and biogeochemical impacts that last for many thousands of years. The future magnitude of such effects will be very closely linked to atmospheric CO2; they will, therefore, depend on the success of emission reduction, and could also be constrained by geoengineering based on most carbon dioxide removal (CDR) techniques. However, some ocean-based CDR approaches would (if deployed on a climatically significant scale) re-locate acidification from the upper ocean to the seafloor or elsewhere in the ocean interior. If solar radiation management were to be the main policy response to counteract global warming, ocean acidification would continue to be driven by increases in atmospheric CO2, although with additional temperature-related effects on CO2 and CaCO3 solubility and terrestrial carbon sequestration.

Continue reading ‘Ocean acidification in a geoengineering context’

Effect of elevated CO2 on the dynamics of particle attached and free living bacterioplankton communities in an Arctic fjord

Published 13 August 2012 Science Closed
Tags: , , , , , ,

The increase in atmospheric carbon dioxide (CO2) results in acidification of the oceans, expected to lead to the fastest drop in ocean pH in the last 300 million years, if anthropogenic emissions are continued at present rate. Due to higher solubility of gases in cold waters and increased exposure to the atmosphere by decreasing ice cover, the Arctic Ocean will be among the areas most strongly affected by ocean acidification. Yet, the response of the plankton community of high latitudes to ocean acidification has not been studied so far. This work is part of the Arctic campaign of the European Project on Ocean Acidification (EPOCA) in 2010, employing 9 in situ mesocosms of about 45 000 l each to simulate ocean acidification in Kongsfjorden, Svalbard (78°56.2′ N 11°53.6′ E). In the present study, we investigated effects of elevated CO2 on the composition and richness of particle attached (PA;> 3 μm) and free living (FL; <3 μm> 0.2 μm) bacterial communities by Automated Ribosomal Intergenic Spacer Analysis (ARISA) in 6 of the mesocosms and the surrounding fjord, ranging from 185 to 1050 initial μatm pCO2. ARISA was able to resolve about 20–30 bacterial band-classes per sample and allowed for a detailed investigation of the explicit richness. Both, the PA and the FL bacterioplankton community exhibited a strong temporal development, which was driven mainly by temperature and phytoplankton development. In response to the breakdown of a picophytoplankton bloom (phase 3 of the experiment), number of ARISA-band classes in the PA-community were reduced at low and medium CO2(∼180–600 μatm) by about 25%, while it was more or less stable at high CO2 (∼ 650–800 μatm). We hypothesise that enhanced viral lysis and enhanced availability of organic substrates at high CO2 resulted in a more diverse PA-bacterial community in the post-bloom phase. Despite lower cell numbers and extracellular enzyme activities in the post-bloom phase, bacterial protein production was enhanced in high CO2-treatments, suggesting a positive effect of community richness on this function and on carbon cycling by bacteria.

Continue reading ‘Effect of elevated CO2 on the dynamics of particle attached and free living bacterioplankton communities in an Arctic fjord’

UN chief launches initiative to protect oceans

Published 13 August 2012 Media coverage Closed

YEOSU (Aug 12, 2012): The UN chief Sunday announced an initiative to protect oceans from pollution and over-fishing and to combat rising sea levels which threaten hundreds of millions of people.

United Nations Secretary General Ban Ki-moon said the initiative, called the Oceans Compact, sets out a strategic vision for the UN system to work more effectively to tackle the “precarious state” of the world’s seas.

Continue reading ‘UN chief launches initiative to protect oceans’

Subscribe

Search

  • Reset

OA-ICC Highlights

Resources