Archive for March, 2016



Scientists call for new strategy to study climate change impacts on coral reefs

MIAMI—An international research team calls for a targeted research strategy to better understand the impact multiple stressors will have on coral reef in the future due to global climate change. The scientists published their new approach to coral reef research in the journal Frontiers in Marine Science.

The researchers conducted a literature review to evaluate recent research on the ecological health impacts of corals when exposed to more than one stressor, such as increased ocean temperature and increased ocean acidification.

More than just bleaching and a loss of calcium shells, changes in temperature and ocean acidification – driven by increased CO2 in the atmosphere – can cause corals to grow more slowly and can inhibit reproduction, according to the researchers. The researchers suggest that when stresses occur simultaneously, they have dangerous effects on corals that are not anticipated by studies that only evaluate a single stressor to corals.

Continue reading ‘Scientists call for new strategy to study climate change impacts on coral reefs’

Invitation to survey: GOA-ON biology observations and map updates

The Global Ocean Acidification Observing Network (GOA-ON) seeks community input guiding its development and, specifically, to inform the 3rd GOA-ON workshop in Hobart during May (www.goa-on.org).

We value your feedback via a short survey on two topics: 1) biological observations that can be used to monitor the impact from OA and 2) updates to the GOA-ON map (www.goa-on.org/Map/), an interactive representation of OA platforms and observing activities.

The survey link is: http://goo.gl/forms/qAu5bYBSsJ

Your reply by 4 April 2016 would be most appreciated.

———————–

Jan Newton and Bronte Tilbrook, GOA-ON3 Co-chairs, on behalf of the GOA-ON Executive Committee and GOA-ON Biology Working Group

Protecting coral reefs with bubbles

Bubbles – yes, bubbles – could help protect coral reefs, oyster farms, and other coastal ecosystems from increasing ocean acidification, according to new research by Stanford scientists.

Blowing tiny bubbles through seawater could help protect coral reefs and oyster farms from oceans turned increasingly acidic through human activities by stripping carbon dioxide (CO2) from coastal marine environments and transferring it to the atmosphere, Stanford scientists say.

The technique, outlined in a study published online in the journal Environmental Science & Technology, could provide a relatively inexpensive solution to one of the biggest threats facing coral reefs today. An estimated 30 to 60 percent of all the coral reefs have died since the Industrial Revolution as the oceans absorbs more CO2 and become increasingly acidic. Ocean acidification harms a variety of marine organisms, but especially those that use calcium carbonate to assemble their skeletons and shells, such as coral, mussels, and oysters.

Continue reading ‘Protecting coral reefs with bubbles’

Ocean acidification roundtable held in Falmouth

FALMOUTH – Congressman Bill Keating and State Representative Tim Madden hosted a roundtable on ocean acidification this Monday at the Woods Hole Research Center in Falmouth.

Attending legislators, government officials, scientists, business leaders, and economic stakeholders from throughout Southeastern Massachusetts discussed the factors that had put the region at the center of the climate issue.

The roundtable also looked for solutions to be implemented on a local, state and federal level.

CapeCodDaily News. Further information.

Legislature to consider $3 million bond to study ocean acidification

In the coming weeks, the Maine Legislature will consider several bond proposals, including a bipartisan measure aimed at, tackling the monumental problem of ocean acidification (OA) in the Gulf of Maine. LD 998, sponsored by Rep. Wayne Parry (R-Arundel) and Rep. Mick Devin (D-Newcastle), would ask voters to approve a bond to borrow $3 million to be used to collect data, monitor waterways and test ocean acidity along the Maine coast and study its impact on wildlife and commercial shellfish species.

“Maine faces a tremendous, fast-evolving environmental challenge,” said Sebastian Belle, executive director of the Maine Aquaculture Association, in testimony last June. “The implications of ocean acidification are only beginning to be understood, but one thing is clear, unless we have the tools to accurately monitor ocean acidification trends, we will be unable to react in terms of management and policy decisions.”

Continue reading ‘Legislature to consider $3 million bond to study ocean acidification’

The influence of carbon dioxide-induced water acidification on the osmotic and metabolic responses of the Baltic amphipod Gammarus oceanicus

The aim of this study was to investigate the effect of CO2-induced water acidification (pH values: 8.1 − control, 7.5 and 7.0) on the hemolymph osmolality and total metabolic rate of amphipod Gammarus oceanicus under short-term exposure. The hemolymph osmolality was measured using a vapor pressure osmometer. The metabolic rate was determined based on the heat dissipation measurements using a Calvet-type isothermal twin calorimeter. The hemolymph osmolality remained unchanged after exposure to pH 7.5 and it increased in the lowest treatment. Acidification did not significantly affect the resting or active metabolic rate. The observed results indicate that high osmolality maintained during hypercapnia did not generate additional physiological costs. It may therefore be concluded that the studied species is preadapted for this factor. The long-term adaptation to hypoosmotic conditions in the brackish Baltic Sea might also have preadapted it to hypercapnia because similar physiological mechanisms are responsible for the resistance to both factors.

Continue reading ‘The influence of carbon dioxide-induced water acidification on the osmotic and metabolic responses of the Baltic amphipod Gammarus oceanicus’

The role of in hospite zooxanthellae photophysiology and reef chemistry on elevated pCO2 effects in two branching Caribbean corals: Acropora cervicornis and Porites divaricata

Previous studies suggest uniform reductions in coral calcification under ocean acidification (OA); however, greater tolerance has been observed under natural diel metabolic signals present on reefs. In addition, few studies have examined the role of in hospite zooxanthellae energetics on coral OA tolerance. In this study, we examined zooxanthellae photosynthesis and coral calcification responses using seawater with natural metabolic dissolved inorganic carbon (DIC) dynamics from a fringing back reef on Little Cayman Island, Caribbean. The experimental design included Acropora cervicornis and Porites divaricata microcolonies grown in continuously flowing seawater with (∼1000 μatm) and without (∼500 μatm) CO2 enrichment to year 2100 predicted levels. Calcification rates were measured weekly, while linear extension and zooxanthellae photosynthesis were determined at the termination of the 28 d experiment. Results showed A. cervicornis microcolonies maintained both photosynthesis and calcification under elevated CO2 partial pressure (pCO2) relative to controls. However, photosynthesis and calcification rates of P. divaricata microcolonies were reduced by ∼80 and 20%, respectively, under relatively high [DIC]:[H+] ratios and aragonite saturation states (Ωarag). Porites divaricata calcification response to elevated pCO2 was linked to photophysiological dysfunction of the algal symbiont, an indicator that this species was metabolically depressed under elevated pCO2. In contrast to calcification, linear extension rates were unaffected by pCO2 in both species. Future studies should investigate how elevated pCO2 may compromise zooxanthellae–coral interactions with an emphasis on DIC uptake pathways.

Continue reading ‘The role of in hospite zooxanthellae photophysiology and reef chemistry on elevated pCO2 effects in two branching Caribbean corals: Acropora cervicornis and Porites divaricata’

Assessing approaches to determine the effect of ocean acidification on bacterial processes

Bacterial extracellular enzymes play a significant role in the degradation of labile organic matter and nutrient availability in the open ocean. Although bacterial production and extracellular enzymes may be affected by ocean acidification, few studies to date have considered the methodology used to measure enzyme activity and bacterial processes. This study investigated the potential artefacts in determining the response of bacterial extracellular glucosidase and aminopeptidase to ocean acidification, and the relative effects of three different acidification techniques. Tests confirmed that the fluorescence of the artificial fluorophores was affected by pH, and that addition of MCA fluorescent substrate alters seawater pH. In experiments testing different acidification methods, bubbling with CO2 gas mixtures resulted in higher β-glucosidase activity relative to acidification by their introduction via gas-permeable silicon tubing, or by acid addition (HCl). In addition, bacterial numbers were 15–40 % higher with bubbling relative to seawater acidified with gas-permeable silicon tubing and HCl. Bubbling may lead to overestimation of carbohydrate degradation and bacterial abundance, and consequently incorrect interpretation of the impacts of ocean acidification on organic matter cycling.

Continue reading ‘Assessing approaches to determine the effect of ocean acidification on bacterial processes’

Impact of pCO2 on the energy, reproduction and growth of the shell of the pearl oyster Pinctada margaritifera

The possible consequences of acidification on pearl farming are disruption of oyster metabolism and change in growth. In the laboratory, we studied the impact of pCO2 (3540, 1338 and 541μatm) on the physiology of pearl oysters exposed for 100 days. This experiment was repeated after an interval of one year. Several physiological compartments were examined in pearl oysters: the scope for growth by measuring ingestion, assimilation and oxygen consumption, gametogenesis by means of histological observations, shell growth by measurement and observation by optical and electronic microscopy, and at molecular level by measuring the expression of nine genes of mantle cells implied in the biomineralisation process. Results from both experiments showed that high pCO2 had no effect on scope for growth and gametogenesis. High pCO2 (3540 μatm) significantly slowed down the shell deposit rate at the ventral side and SEM observations of the inside of the shell found signs of chemical dissolution. Of the nine examined genes high pCO2significantly decreased the expression level of one gene (Pmarg-PUSP 6). This study showed that shell growth of the pearl oyster would be slowed down without threatening the species since the management of energy and reproduction functions appeared to be preserved. Further investigations should be conducted on the response of offspring to acidification.

Continue reading ‘Impact of pCO2 on the energy, reproduction and growth of the shell of the pearl oyster Pinctada margaritifera’

Marine projections of warming and ocean acidification in the Australasian region

In response to increasing carbon dioxide emissions the oceans have become warmer and more acidic. In this paper, the ability of Earth System Models to simulate observed temperature and ocean acidification around Australia is as-sessed. The model results are also compared with observations collected at sta-tions around Australia over recent years to assess how representative the model results are of the coastal domain; and are found to adequately simulate the mean state at most sites.

Simulations from the Coupled Model Intercomparison Project 5 (CMIP5) under low, medium and high emissions scenarios (RCPs 2.6, 4.5 and 8.5 respectively) are then used to project how ocean acidification and sea surface temperature will change. Under each of these emissions scenarios the oceans around Austral-ia exhibit warming and continued acidification. However, these changes are quite heterogeneous, with increases of up to +6 K (under RCP 8.5) above the pre-industrial value, projected in areas such as the Tasman Sea. We conclude that the projected changes in SST, aragonite saturation state and pH are likely to profoundly impact marine ecosystems, and the ecosystem services that they provide in the Australasian region.

Continue reading ‘Marine projections of warming and ocean acidification in the Australasian region’


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Ocean acidification in the IPCC AR5 WG II

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