High resolution pH measurements using a lab-on-chip sensor in surface waters of northwest european shelf seas

Increasing atmospheric CO2 concentrations are resulting in a reduction in seawater pH, with potential detrimental consequences for marine organisms. Improved efforts are required to monitor the anthropogenically driven pH decrease in the context of natural pH variations. We present here a high resolution surface water pH data set obtained in summer 2011 in North West European Shelf Seas. The aim of our paper is to demonstrate the successful deployment of the pH sensor, and discuss the carbonate chemistry dynamics of surface waters of Northwest European Shelf Seas using pH and ancillary data. The pH measurements were undertaken using spectrophotometry with a Lab-on-Chip pH sensor connected to the underway seawater supply of the ship. The main processes controlling the pH distribution along the ship’s transect, and their relative importance, were determined using a statistical approach. The pH sensor allowed 10 measurements h−1 with a precision of 0.001 pH units and a good agreement with pH calculated from a pair of discretely sampled carbonate variables dissolved inorganic carbon (DIC), total alkalinity (TA) and partial pressure of CO2 (pCO2) (e.g., pHDICpCO2). For this summer cruise, the biological activity formed the main control on the pH distribution along the cruise transect. This study highlights the importance of high quality and high resolution pH measurements for the assessment of carbonate chemistry dynamics in marine waters.

Continue reading ‘High resolution pH measurements using a lab-on-chip sensor in surface waters of northwest european shelf seas’

Ocean acidification: falling between the legal cracks of UNCLOS and the UNFCCC ?

Oceans have played a critical role in shielding Earth from some of the more serious impacts of climate change by absorbing approximately 30 percent of emitted anthropogenic carbon dioxide. However, this has resulted in an approximate 26 percent increase in acidity of oceans since the industrial period. This not only presents the scientific challenge of addressing the problem of ocean acidification and its impacts on ocean marine life, but also presents many legal challenges. This Article will assess if the existing international legal framework provides the necessary foundation to address these legal challenges. Specifically, this Article will analyze whether two key global regimes, the United Nations Framework Convention on Climate Change and United Nations Convention on the Law of the Sea, provide the necessary legal foundation to address ocean acidification. It concludes that while UNCLOS establishes the legal obligation of States to address ocean acidification, it does not by itself provide for the framework for taking the collective action needed for a significant reduction in carbon dioxide emissions. By contrast, the United Nations Framework Convention on Climate Change regime appears to provide a better vehicle for the collective action necessary to mitigate emissions of carbon dioxide causing ocean acidification.

Continue reading ‘Ocean acidification: falling between the legal cracks of UNCLOS and the UNFCCC ?’

Bioeconomic analysis of the impact of ocean acidification associated with low recruitment of Isostichopus badionotus and implications for adaptive fishery management in the north of the Yucatan Peninsula, Mexico

The impact that ocean acidification (OA) could generate in the fisheries of Isostichopus badionotus at the north of the Yucatan Peninsulta, Mexico, was analysed by reducing the value of a parameter of the Beverton-Holt recruitment function, in accordance with the acidification scenarios of the Intergovermental Panel Panel on Climate Change (IPCC). The behaviour of the stock and the resulting fishery were analysed in a bioeconomic model structured by age, taking into account different market prices and fishing efforts. The results were compared in decision matrices that used the MiniMax and MaxMin criteria to determine the management strategy that best reduced the impact of  acidification. The largest stock reduction occurred during the first years of exploitation (B10>B15/BO) and all the variables that were considered did stabilize with time, reaching bioeconomic equilibrium. The worst scenario for not considering acidification occurred with low market prices, while the increase in price decreased the exploitation rate. The recruitment reduction determined the maximum effort that should have been applied; under such conditions it is recommended to operate an effort of 137 boats, considering the best market price.

Continue reading ‘Bioeconomic analysis of the impact of ocean acidification associated with low recruitment of Isostichopus badionotus and implications for adaptive fishery management in the north of the Yucatan Peninsula, Mexico’

Impact of ocean acidification on thermal tolerance and acid–base regulation of Mytilus edulis from the White Sea

Ocean warming and acidification are two important environmental drivers affecting marine organisms. Organisms living at high latitudes might be especially threatened in near future, as current environmental changes are larger and occur faster. Therefore, we investigated the effect of hypercapnia on thermal tolerance and physiological performance of sub-Arctic Mytilus edulis from the White Sea. Mussels were exposed (2 weeks) to 390 µatm (control) and 1120 µatm CO2 (year 2100) before respiration rate (MO2), anaerobic metabolite (succinate) level, haemolymph acid–base status and intracellular pH (pHi) were determined during acute warming (10–28 °C, 3 °C over night). In normocapnic mussels, warming induced MO2 to rise exponentially until it levelled off beyond a breakpoint temperature of 20.5 °C. Concurrently, haemolymph PCO2 rose significantly > 19 °C followed by a decrease in PO2 indicating the pejus temperature (TP, onset of thermal limitation). Succinate started to accumulate at 28 °C under normocapnia defining the critical temperature (TC). pHi was maintained during warming until it dropped at 28 °C, in line with the concomitant transition to anaerobiosis. At acclimation temperature, CO2 had only a minor impact. During warming, MO2 was stimulated by CO2 resulting in an elevated breakpoint of 25.8 °C. Nevertheless, alterations in haemolymph gases (> 16 °C) and the concomitant changes of pHi and succinate level (25 °C) occurred at lower temperature under hypercapnia versus normocapnia indicating a downward shift of both thermal limits TP and TC by CO2. Compared to temperate conspecifics, sub-Arctic mussels showed an enhanced thermal sensitivity, exacerbated further by hypercapnia, indicating their potential vulnerability to environmental changes projected for 2100.

Continue reading ‘Impact of ocean acidification on thermal tolerance and acid–base regulation of Mytilus edulis from the White Sea’

The absence of the pCO2 effect on dissolved 134Cs uptake in select marine organisms

Highlights

• Prawns and scallops were exposed to dissolved 134Cs at three increasing pCO2.
• Increasing pCO2 had no effect on the uptake kinetics parameters whatever the species.
• Prawn concentrated ca. 10-fold more efficiently 134Cs than scallop at equilibrium.

Abstract

Ocean acidification have been shown to not affect the capacity of bivalves to bioaccumulation 134Cs in their tissue; but as this was studied on only one species to date. There is therefore a need to verify if this holds true for other bivalve species or other marine invertebrates. The present short communication confirms that in the scallop Mimachlamys varia and the prawn Penaeus japonicus, two species that supposedly have a record to preferentially concentrates this radionuclide, that bioconcentration of 134Cs was shown not to be influenced by a decreasing pH (and thereby increasing seawater pCO2). Although the dissolved 134Cs was taken up in a similar manner under different pH values (8.1, 7.8, and 7.5) in both species, being described by a saturation state equilibrium model, the species displayed different bioconcentration capacities of 134Cs: CFss in the prawns was approximately 10-fold higher than in scallops. Such results suggest that the Cs bioconcentration capacity are mainly dependent of the taxa and that uptake processes are independent the physiological ones involved in the biological responses of prawns and scallops to ocean acidification.

Continue reading ‘The absence of the pCO2 effect on dissolved 134Cs uptake in select marine organisms’

Effects of ocean acidification on 109Cd, 57Co, and 134Cs bioconcentration by the European oyster (Ostrea edulis): Biokinetics and tissue-to-subcellular partitioning

Highlights

• A decrease in pH does not affect the uptake kinetics of 109Cd and 57Co, nor the depuration of 109Cd and 134Cs.
• Depuration kinetics of 57Co is modified as pC02 conditions change.
• No variation in the subcellular sequestration of these three trace elements under low pH conditions.
• A systematic bleaching of the oyster shells was observed with a drop in pH over 40 days.

Abstract

The uptake and depuration kinetics of dissolved 109Cd, 57Co and 134Cs were determined experimentally in the European flat oyster Ostrea edulis (Linnaeus, 1758) under different pH conditions (i.e., 8.1, 7.8 and 7.5) for 59 days. Uptake and depuration rates were variable within these elements; no effects were observed under different pH conditions for the uptake biokinetics of 109Cd and 57Co and depuration of 109Cd and 134Cs in oyster. The uptake and depuration rate constants of 134Cs differed during the exposure phase between treatments, while the steady state concentration factors (CFss) were similar. The resulting Cs activity that was purged during short- and long-term depuration phases differed, while the remaining activities after thirty-nine days depuration phase (RA39d) were similar. Co-57 depuration was affected by pCO2 conditions: RA39d were found to be significantly higher in oysters reared in normocapnia (pCO2 = 350 μatm) compared to high pCO2 conditions. Co-57 tissue distribution did not differ among the variable pCO2 conditions, while 109Cd and 134Cs accumulated in soft tissue of oysters were found to be higher under the highest pCO2. Additionally, Cd, Co and Cs were stored differently in various compartments of the oyster cells, i.e. cellular debris, metal-rich granules (MRG) and metallothionein-like proteins (MTLP), respectively. The subcellular sequestration of the elements at the end of the depuration phase did not differ among pH treatments. These results suggest that bioconcentration and tissue/subcellular distribution are element-specific in the oyster, and the effects of higher pCO2 driven acidification and/or coastal acidification variably influence these processes.

Continue reading ‘Effects of ocean acidification on 109Cd, 57Co, and 134Cs bioconcentration by the European oyster (Ostrea edulis): Biokinetics and tissue-to-subcellular partitioning’

Commission on ocean acidification is now law

Rep. Dylan Fernandes and State Senator Julian Cyr talk about the new Ocean Acidification Commission (Courtesy of Senator Cyr)

Senator Julian Cyr (D-Truro) and Representative Dylan Fernandes (D-Falmouth) held a press conference today to discuss the formation of legislation, which is now law, that calls for a special commission to determine the extent to which coastal and ocean acidification impacts commercially valuable marine species along the Massachusetts coastline. The establishment of this commission aims to address critical scientific and general knowledge “gaps” that may hinder the Commonwealth’s ability to craft policy and other responses to coastal and ocean acidification.

The press conference was held at the Cape Cod Oyster Company in Marstons Mills, with local leaders from Barnstable County, the Woods Hole Oceanographic Institute, the Marine Biological Laboratory, local aquaculture and shellfish business owners, the Cape Cod Commercial Fishermen’s Alliance, among others.

Senator Cyr and Rep. Fernandes both filed legislation relative to studying the acidification of our oceans in January 2017. Senator Cyr then successfully proposed the text of the bill as an amendment to the Environmental Bond Bill in June 2018, which was signed by the Governor in August 2018.

Continue reading ‘Commission on ocean acidification is now law’


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OA-ICC HIGHLIGHTS

Ocean acidification in the IPCC AR5 WG II

OUP book