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Rapid warming and salinity changes in the Gulf of Maine alter surface ocean carbonate parameters and hide ocean acidification

A profound warming event in the Gulf of Maine during the last decade has caused sea surface temperatures to rise to levels exceeding any earlier observations recorded in the region over the last 150 years. This event dramatically affected CO2 solubility and, in turn, the status of the sea surface carbonate system. When combined with the concomitant increase in sea surface salinity and assumed rapid equilibration of carbon dioxide across the air sea interface, thermodynamic forcing partially mitigated the effects of ocean acidification for pH, while raising the saturation index of aragonite (ΩARΩAR ) by an average of 0.14 U. Although the recent event is categorically extreme, we find that carbonate system parameters also respond to interannual and decadal variability in temperature and salinity, and that such phenomena can mask the expression of ocean acidification caused by increasing atmospheric carbon dioxide. An analysis of a 34-year salinity and SST time series (1981–2014) shows instances of 5–10 years anomalies in temperature and salinity that perturb the carbonate system to an extent greater than that expected from ocean acidification. Because such conditions are not uncommon in our time series, it is critical to understand processes controlling the carbonate system and how ecosystems with calcifying organisms respond to its rapidly changing conditions. It is also imperative that regional and global models used to estimate carbonate system trends carefully resolve variations in the physical processes that control CO2 concentrations in the surface ocean on timescales from episodic events to decades and longer.

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Meeting: NYS Ocean Acidification Task Force

Date: 1 November 2018 6:30 PM – 8:30 PM (US Eastern)

Location: 20 Endeavour Hall, South Campus, Stony Brook University, Stony Brook, NY 11794

Description:  The Ocean Acidification Task Force works to assess the impacts of ocean acidification on the ecological, economic, and social well-being of the State of New York in order to recommend actions to reduce these impacts. All are invited to observe and participate in this process.

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Time to take ocean acidification seriously

From 2007 to 2010, major shellfish hatcheries supplying the seed for West Coast oyster growers suffered persistent production failures. Hatchery scientists were witnessing baby larval oysters (just the size of the width of an eyelash) completely dissolving before their eyes. It wasn’t until 2012 that a group of researchers at Oregon State University confirmed that the collapse in oyster seed production was due to ocean acidification.

Due to various factors, the northern Pacific Ocean is more prone to ocean acidification than the northern Atlantic Ocean; however, we are now beginning to see the effects locally. Luckily, we can implement the West Coast hatchery solutions to overcome the short-term acidification problems, but more research is needed to learn how our fisheries will be impacted long-term.

The aquaculture industry is the fastest growing food sector in the U.S. (5 percent growth annually since 2010), and shellfish farming on the Island currently generates about $4 million annually into our local economy.

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PERSGA Member States trained on ocean acidification in Aqaba


Credit: PERSGA

A group of 26 participants representing 7 Member States (Djibouti, Egypt, Jordan, Kingdom of Saudi Arabia, Somalia, Sudan and Yemen) of the Regional Organization for the Conservation of the Environment of the Red Sea and Gulf of Aden (PERSGA), had the opportunity to attend a 5-day introductory course on ocean acidification in Aqaba, Jordan from 30 September to 4 October 2018. This regional workshop was organized by PERSGA in partnership with the IAEA Ocean Acidification International Coordination Centre (OA-ICC), The Aqaba Special Economic Zone Authority (ASEZA) and the Marine Science Station (MSS)/University of Jordan and Yarmouk University.

The workshop sought to give participants entering the field of ocean acidification a solid overview of the topic, from the underlying chemistry to its impacts on marine organisms and ecosystems. It introduced methods used to monitor ocean acidification in the field, as well as approaches to assess the risk to marine life using lab experiments. An international group of experts shared their expertise in ocean acidification research through lectures and practical demonstrations.

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Scallop fishery may be imperiled by acidic seas


Acidification poses a threat to the sea scallop industry, according to a recent report by WHOI. — Caroline Brehman

Increasingly acidic seas pose a serious threat to the sea scallop fishery, a recent collaborative study by the University of Virginia, the Ocean Conservancy, the NOAA Northeast Fisheries Science Center, and the Woods Hole Oceanographic Institution (WHOI) concluded.


“As levels of carbon dioxide increase in Earth’s atmosphere, the oceans become increasingly acidic — a condition that could reduce the sea scallop population by more than 50 percent in the next 100 years under a worst-case scenario,” the study states. Models from the study, which were published recently in the journal PLOS One, combine existing data with several factors that impact the fishery: “future climate change scenarios, ocean acidification impacts, fisheries management policies, and fuel costs for fishermen.” Those factors were modeled out into 256 different possibilities.

Oceans absorb vast quantities of carbon dioxide. Fossil fuel emissions exacerbate what the oceans take in, further acidifying the water. “That acidity can corrode the calcium carbonate shells that are made by shellfish like clams, oysters, and scallops, and even prevent their larvae from forming shells in the first place,” the study states.

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The importance of natural acidified systems in the study of ocean acidification: what have we learned?

Human activity is generating an excess of atmospheric CO2, resulting in what we know as ocean acidification, which produces changes in marine ecosystems. Until recently, most of the research in this area had been done under small-scale, laboratory conditions, using few variables, few species and few life cycle stages. These limitations raise questions about the reproducibility of the environment and about the importance of indirect effects and synergies in the final results of these experiments. One way to address these experimental problems is by conducting studies in situ, in natural areas where expected future pH conditions already occur, such as CO2 vent systems. In the present work, we compile and discuss the latest research carried out in these natural laboratories, with the objective to summarize their advantages and disadvantages for research to improve these investigations so they can better help us understand how the oceans of the future will change.

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Indications of future performance of native and non-native adult oysters under acidification and warming


• Acidification and warming negatively impacted the physiology of Magallana gigas.
Ostrea edulis appeared unaffected by the treatment conditions.
• Efforts to promote the restoration of native O. edulis beds should be pursued.
• Efforts to eradicate M. gigas populations may need to be reconsidered.


Globally, non-native species (NNS) have been introduced and now often entirely replace native species in captive aquaculture; in part, a result of a perceived greater resilience of NSS to climate change and disease. Here, the effects of ocean acidification and warming on metabolic rate, feeding rate, and somatic growth was assessed using two co-occurring species of oysters – the introduced Pacific oyster Magallana gigas (formerly Crassostrea gigas), and native flat oyster Ostrea edulis. Biological responses to increased temperature and pCO2 combinations were tested, the effects differing between species. Metabolic rates and energetic demands of both species were increased by warming but not by elevated pCO2. While acidification and warming did not affect the clearance rate of O. edulis, M. gigas displayed a 40% decrease at ∼750 ppm pCO2. Similarly, the condition index of O. edulis was unaffected, but that of M. gigas was negatively impacted by warming, likely due to increased energetic demands that were not compensated for by increased feeding. These findings suggest differing stress from anthropogenic CO2 emissions between species and contrary to expectations, this was higher in introduced M. gigas than in the native O. edulis. If these laboratory findings hold true for populations in the wild, then continued CO2 emissions can be expected to adversely affect the functioning and structure of M. gigas populations with significant ecological and economic repercussions, especially for aquaculture. Our findings strengthen arguments in favour of investment in O. edulis restoration in UK waters.

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Ocean acidification in the IPCC AR5 WG II

OUP book