Blockchain now being utilized for reducing ocean acidification

The seafood industry now also relies on the disruptive technology.

According to Breaker, Blockchain could easily address the current bottlenecks in the seafood industry — overfishing, mislabeling, etc. Meanwhile, Kat Leigh, who leads a project dubbed FishcoinOA, wants to use Blockchain in order to tackle one of the biggest environmental disasters — ocean acidification.

Understanding ocean acidification  

As U.Today reported earlier, the global agribusiness is already diving deep in Blockchain with US tech behemoth IBM launching its own food-tracking product that is already being utilized by big names in the likes of Walmart and Carrefour. Now, Blockchain is poised to battle ocean acidification.

Ocean acidification is a large-scale environmental problem that is caused by CO2 emission that lowers the ocean’s pH level. Fish organisms are struggling with acidic conditions; although, it’s unlikely that the ocean will turn into actual acid, falling below a pH of 7.0. To put this into perspective, the global economy is expected to lose up to $1 trln due to ocean acidification.

Fishers and Fishcoin

During the interview, Leigh claimed that ocean acidification is also particularly cunning since it’s very hard to detect due to numerous factors influencing the ocean chemistry. The purpose of the FishCoinOA project is to collect all kinds of information related to the problem.

All the data is collected with small sensors that are connected to fishers’ phones. In order to pinpoint the location of the readings, it simply takes to enable GPS on a smartphone. Fishers who contribute valuable information — catch data, origin, etc. — to the network are rewarded with Fishcoin tokens. Since the detection of ocean acidification requires constant connectivity, these tokens can be redeemed for any GSMA data plan.

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Response of pelagic calcifiers (Foraminifera, Thecosomata) to ocean acidification during oligotrophic and simulated up-welling conditions in the subtropical North Atlantic off Gran Canaria

Planktonic Foraminifera and thecosome pteropods are major producers of calcite and aragonite in the ocean and play an important role for pelagic carbonate flux. The responses of planktonic foraminifers to ocean acidification (OA) are variable among the species tested and so far do not allow for reliable conclusion. Thecosome pteropods respond with reduced calcification and shell dissolution to OA and are considered at high risk especially at high latitudes. The present investigation was part of a large-scale in situ mesocosm experiment in the oligotrophic waters of the eastern subtropical North Atlantic. Over 62 days, we measured the abundance and vertical flux of pelagic foraminifers and thecosome pteropods as part of a natural plankton community over a range of OA scenarios. A bloom phase was initiated by the introduction of deep-water collected from approx. 650 m depth simulating a natural up-welling event. Foraminifers occurred throughout the entire experiment in both the water column and the sediment traps. Pteropods were present only in small numbers and disappeared after the first two weeks of the experiment. No significant CO2 related effects were observed for foraminifers, but cumulative sedimentary flux was reduced at the highest CO2 concentrations. This flux reduction was most likely accompanying an observed flux reduction of particulate organic matter (POM) so that less foraminifers were intercepted and transported downward.

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Drivers of carbon and oxygen dynamics in disparate marine ecosystems

Determining the change of sea surface CO2 fugacity (fCO2) is important as the fCO2 gradient between the atmosphere and the ocean dictates the direction of CO2 flux and the fate of this greenhouse gas. While substantial efforts have been dedicated to the study of fCO2 trends in the open ocean, little is known regarding how fCO2 levels change in ocean margins. Meanwhile, hypoxia (i.e., dissolved oxygen concentration, or DO, less than 2 mg L-1) is becoming an increasing global threat in coastal areas. Elucidating the carbon sources that consume DO is important because it helps to make proper mitigation plans. In Chapter II, I used a newly available, community-based global CO2 database (Surface Ocean CO2 Atlas version 3) to develop a new statistical approach based on Generalized Additive Mixed Modeling (GAMM) to interpret oceanic fCO2 changes in ocean margins. This method utilized Julian day of year, sea surface salinity, sea surface temperature, and sampling date as predictors. Using the GAMM method, I was able to derive multi-decadal fCO2 trends with both improved precision and greater robustness to data gaps compared to the existing method. In Chapter III, I used the GAMM method on global ocean margins (within 400 km from the shore and 30°S-70°N) and found that fCO2 trends closely followed the atmospheric fCO2 increase rate. Further analysis suggested that fCO2 trends in Western Boundary Current- and Eastern Boundary Current-influenced areas differed in response to thermal (temperature) and nonthermal (chemical and biological) effects. These differences were due to heterogonous physical, chemical, and biological responses under climate change forcing, leading to divergent trends in CO2 sinks and sources among different ocean margins. To address the hypoxia formation mechanism question, I adopted the stable carbon isotope (δ13C) of dissolved inorganic carbon (or DIC, the end product of organic carbon degradation) as a proxy to trace back the δ13C of remineralized organic carbon that was responsible for DO consumption in the northern Gulf of Mexico (Chapter IV) and two semi-arid coastal bays in south Texas (Baffin Bay and Oso Bay) (Chapter V), the two areas that both experience seasonal bottom water hypoxia. My findings suggested that terrestrial carbon contributed to oxygen consumption in limited extent and mostly focused in areas where river water influence was significant in the northern Gulf of Mexico, while for the vast shelf areas marine-produced organic carbon was the dominant contributor to hypoxia formation. In Baffin Bay and Oso Bay, however, phytoplankton, seagrass/marsh organic carbon, and refractory terrestrial organic carbon all contributed to the DO loss under different hydrological conditions. This study provided a comprehensive data-driven analysis on ocean margin fCO2 changes on a multi-decadal timescale and revealed different behaviors of the two types of boundary current-dominated systems. Regarding the hypoxia formation mechanism in the different coastal and estuarine environments, my study suggested that eutrophication remained the top stressor that could lead to hypoxia formation. Therefore, sustained efforts that focus on reducing nutrient pollution should still be carried out to mitigate the hypoxia stress for the both ecologically and economically important coastal and estuarine systems.

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Modeling impact of varying pH due to carbondioxide on the dynamics of prey–predator species system

In this paper, we have considered a nonlinear mathematical model to investigate the effect of pH on prey–predator dynamics with Holling type II functional response. In the model, capture rate, handling time, growth rate and death rate are considered to be pH dependent. From the analysis of the model, it has been observed that as pH level goes below the normal tolerance limit of prey species then the equilibrium density of prey population decreases due to increase in capture rate and decrease in handling time by predator. Further, we have shown that as the growth rate of prey population decreases due to lowering of pH then the density of predator population also decreases and both the populations may tend to extinction if growth rate of prey population becomes negative due to lowering of pH on account of elevated carbondioxide concentration in the aquatic body. Moreover, it is noticed from the simulation that if the mortality of predator population increases because of decrease in pH level then the prey population gets advantage and in-turn their population increases.

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The impact of ocean acidification on the byssal threads of the blue mussel (Mytilus edulis)

Blue mussel (Mytilus edulis) produce byssal threads to anchor themselves to the substrate. These threads are always exposed to the surrounding environmental conditions. Understanding how environmental pH affects these threads is crucial in understanding how climate change can affect mussels. This work examines three factors (load at failure, thread extensibility, and total thread counts) that indicate the performance of byssal threads as well as condition index to assess impacts on the physiological condition of mussels held in artificial seawater acidified by the addition of CO2. There was no significant variation between the control (~786 μatm CO2 / ~7.98 pH/ ~2805 μmol kg-1 total alkalinity) and acidified (~2555 μatm CO2 / ~7.47 pH/ ~2650 μmol kg-1 total alkalinity) treatment groups in any of these factors. The results of this study suggest that ocean acidification by CO2 addition has no significant effect on the quality and performance of threads produced by M. edulis.

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The ability of macroalgae to mitigate the negative effects of ocean acidification on four species of North Atlantic bivalve (updated)

Coastal ecosystems can experience acidification via upwelling, eutrophication, riverine discharge, and climate change. While the resulting increases in pCO2 can have deleterious effects on calcifying animals, this change in carbonate chemistry may benefit some marine autotrophs. Here, we report on experiments performed with North Atlantic populations of hard clams (Mercenaria mercenaria), eastern oysters (Crassostrea virginica), bay scallops (Argopecten irradians), and blue mussels (Mytilus edulis) grown with and without North Atlantic populations of the green macroalgae, Ulva. In six of seven experiments, exposure to elevated pCO2 levels ( ∼ 1700µatm) resulted in depressed shell- and/or tissue-based growth rates of bivalves compared to control conditions, whereas rates were significantly higher in the presence of Ulva in all experiments. In many cases, the co-exposure to elevated pCO2 levels and Ulva had an antagonistic effect on bivalve growth rates whereby the presence of Ulva under elevated pCO2 levels significantly improved their performance compared to the acidification-only treatment. Saturation states for calcium carbonate (Ω) were significantly higher in the presence of Ulva under both ambient and elevated CO2 delivery rates, and growth rates of bivalves were significantly correlated with Ω in six of seven experiments. Collectively, the results suggest that photosynthesis and/or nitrate assimilation by Ulva increased alkalinity, fostering a carbonate chemistry regime more suitable for optimal growth of calcifying bivalves. This suggests that large natural and/or aquacultured collections of macroalgae in acidified environments could serve as a refuge for calcifying animals that may otherwise be negatively impacted by elevated pCO2 levels and depressed Ω.

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The impacts of iron limitation and ocean acidification on the cellular stoichiometry, photophysiology, and transcriptome of Phaeocystis antarctica

Phaeocystis antarctica is an integral player of the phytoplankton community of the Southern Ocean (SO), the world’s largest high-nutrient low-chlorophyll region, and faces chronic iron (Fe) limitation. As the SO is responsible for 40% of anthropogenic CO2 uptake, P. antarctica must also deal with ocean acidification (OA). However, mechanistic studies investigating the effects of Fe limitation and OA on trace metal (TM) stoichiometry, transcriptomic, and photophysiological responses of this species, as well as on the Fe chemistry, are lacking. This study reveals that P. antarctica responded strongly to Fe limitation by reducing its growth rate and particulate organic carbon (POC) production. Cellular concentrations of all TMs, not just Fe, were greatly reduced, suggesting that Fe limitation may drive cells into secondary limitation by another TM. P. antarctica was able to adjust its photophysiology in response to Fe limitation, resulting in similar absolute electron transport rates across PSII. Even though OA-stimulated growth in Fe-limited and -replete treatments, the slight reduction in cellular POC resulted in no net effect on POC production. In addition, relatively few genes were differentially expressed due to OA. Finally, this study demonstrates that, under our culture conditions, OA did not affect inorganic Fe or humic-acid-like substances in seawater but triggered the production of humic-acid-like substances by P. antarctica. This species is well adapted to OA under all Fe conditions, giving it a competitive advantage over more sensitive species in a future ocean.

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A validation and comparison study of new, compact, versatile optodes for oxygen, pH and carbon dioxide in marine environments


• New optical sensors for oxygen, pH and carbon dioxide are deployed in various marine environments
• The data collected by the optical sensors are in very good agreement with the values obtained with commercially available reference systems
• Anti-biofouling strategy with copper guard is shown to be efficient for long term monitoring in highly active environments
• Compact and low cost device with autonomous logging and interchangeable sensing caps is proved to be promising for oceanographic applications


Continuous monitoring of dissolved oxygen, pH and carbon dioxide are of great importance in oceanography. Sensors are the optimal tools for in situ measurements from mobile platforms, like Autonomous Underwater Vehicles (AUVs) or Argo profiling floats, and for shipboard deployments. A validation study of small, versatile, easy-to-use, stand-alone optodes is presented. Each analyte can be read out with the identical optoelectronics which greatly minimizes the costs of the hardware needed. Several deployments were performed to evaluate the applicability of the sensors. The deployments varied in terms of duration (profiling, long-term monitoring 5 days to 8 weeks) and environmental conditions (salinity: 6–33 PSS; temperature: 9–25 °C). A set of sensors was successfully deployed at a mooring buoy, in an aquaculture facility and in the Monterey Bay Aquarium Open Sea Exhibition. They were also integrated in an AUV and a profiling float. The performance of the optodes was evaluated in comparison with commercially available sensors for dissolved oxygen (Aanderaa Data Instruments AS, Sea-Bird Scientific, OxyGuard®), pH (Hach, Satlantic) and carbon dioxide (Turner design). The data collected by our optodes and the commercially available sensors is generally in good agreement showing that the new, compact sensor device in combination with sensor foils (pO2, pH, pCO2) can be a valuable tool for many applications in oceanography. The data also revealed the importance of the calibration strategy since inappropriate calibration resulted in an offset in the measured parameter. The efficiency of simple biofouling protection strategy (copper guard) for prolong measurements in highly dynamic environments was also demonstrated.

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Modeling the variability, trends and future changes in ocean acidification in the Humboldt Current System

The largest buffer against climate change is the oceanic sink of anthropogenic CO2. However, this important ecosystem service to humanity leads to the reduction of pH and the saturation state of the biologically relevant calcium carbonate minerals aragonite and calcite  (Ωarag and Ωcalc). This process, known as anthropogenic ocean acidification, is a major marine ecosystem stressor and has negative impacts that range from reduced calcification to changes in population dynamics of important fisheries. Some of the most productive regions of the world, the Eastern Boundary Upwelling Systems (EBUS), are also among the most vulnerable to become undersaturated in the next decades due to the natural occurrence of low pH and Ω values at shallow depths and the projected further uptake of anthropogenic CO2. While extensive research on ocean acidification has been conducted in the California Current upwelling System, little is known about the dynamics of the marine carbonate chemistry in the much more productive Humboldt Current Upwelling System (HumCS), in the west coast of South America. To fill this gap, I used the high resolution Regional Ocean Modelling System (ROMS) and two different ecosystem models to study the progression of ocean acidification in the HumCS and the natural fluctuations superimposed to this anthropogenic perturbation. Results from a preindustrial simulation (year 1870) show that even then, pH and Ωarag values in the HumCS were respectively ⇠ 0.3 and 1 units lower than the preindustrial global average. The simulated evolution of ocean acidification to the end of the century showed that the continuous uptake of anthropogenic CO2 will push the nearshore off Peru to even lower values, from a present-day pH of 7.8 and Ωarag of 1.8 to year-round undersaturated conditions in year 2090 in at least 60 % of the top layer of the water column in the nearshore off Peru. Aragonite undersaturation in the following decades is already a committed change regardless of the amount of carbon emitted to the atmosphere in the future. However, a striking difference arises between following a “high CO2 emissions” scenario (RCP8.5, pCO2 values 840 μatm by year 2090) or a “low CO2 emissions” scenario (RCP2.6, pCO2 values of 428 μatm). In the former, water corrosive to calcite, a less soluble form of calcium carbonate than aragonite, will be found in the first 15 km off Peru and will potentially impact a larger range of calcifying organisms. On the other hand, this can be avoided the RCP2.6 scenario is followed, and strong CO2 mitigation measures are established and executed. In the high CO2 emissions scenario, an overall decrease of 0.9 ± 0.1 units in Ωarag from present day to the end of the century is projected in the nearshore off Peru, and a similar trend in the nearshore off Chile. On top of this long-term trend, natural climate variability off Peru can lead to strong year-to-year variations in the progression of ocean acidification. The largest contribution to Ωarag variability in the HumCS is on the interannual timescale, mainly forced by remotely forced tropical oscillations (e.g. El Ni˜no/Southern Oscillation) but also by local and regional phenomena (e.g., El Ni˜no costero). Analysis from a hindcast simulation for the period of 1979-2016 reveals that under present day conditions, the magnitude of such variability is comparable to the anthropogenic trend. Interannual changes in Ω are mainly driven by variations in the thermocline structure and wind patterns. Off Peru, the deepening of the thermocline associated with warm, El Ni˜no-like events, is translated into an increase in Ωarag in the surface layer of 0.4 units, while a shallower thermocline driven by cold interannual events (e.g., La Ni˜na) leads to a decrease in Ωarag values of 0.3 units. These natural interannual variations account for ⇠ 30 to and 40 % of the magnitude of the expected anthropogenic change, potentially bringing forward of delaying by some decades the pervasive appearance of aragonite undersaturated waters in the surface layer of the most productive EBUS of the Pacific: the Humboldt Current.

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Assessing the impacts of ocean acidification on adhesion and shell formation in the barnacle Amphibalanus amphitrite

Barnacles are dominant members of marine intertidal communities. Their success depends on firm attachment provided by their proteinaceous adhesive and protection imparted by their calcified shell plates. Little is known about how variations in the environment affect adhesion and shell formation processes in barnacles. Increased levels of atmospheric CO2 have led to a reduction in the pH of ocean waters (i.e., ocean acidification), a trend that is expected to continue into the future. Here, we assessed if a reduction in seawater pH, at levels predicted within the next 200 years, would alter physiology, adhesion, and shell formation in the cosmopolitan barnacle Amphibalanus (=Balanus) amphitrite. Juvenile barnacles, settled on silicone substrates, were exposed to one of three static levels of pHT, 8.01, 7.78, or 7.50, for 13 weeks. We found that barnacles were robust to reduced pH, with no effect of pH on physiological metrics (mortality, tissue mass, and presence of eggs). Likewise, adhesive properties (adhesion strength and adhesive plaque gross morphology) were not affected by reduced pH. Shell formation, however, was affected by seawater pH. Shell mass and base plate area were higher in barnacles exposed to reduced pH; barnacles grown at pHT 8.01 exhibited approximately 30% lower shell mass and 20% smaller base plate area as compared to those at pHT 7.50 or 7.78. Enhanced growth at reduced pH appears to be driven by the increased size of the calcite crystals that comprise the shell. Despite enhanced growth, mechanical properties of the base plate (but not the parietal plates) were compromised at the lowest pH level. Barnacle base plates at pHT 7.50 broke more easily and crack propagation, measured through microhardness testing, was significantly affected by seawater pH. Other shell metrics (plate thickness, relative crystallinity, and atomic disorder) were not affected by seawater pH. Hence, a reduction in pH resulted in larger barnacles but with base plates that would crack more readily. It is yet to be determined if such changes would alter the survival of A. amphitrite in the field, but changes in the abundance of this ecologically dominant species would undoubtedly affect the composition of biofouling communities.

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Boric acid and borate incorporation in inorganic calcite inferred from B/Ca, boron isotopes and surface kinetic modeling

The boron concentration (B/Ca ratio) and isotopic composition (δ11B) of biogenic calcite are widely applied to reconstruct past changes in seawater carbonate chemistry. Knowledge of B incorporation pathways into calcite is critical for these applications and for improving the theoretical basis of B proxies. While the canonical interpretation of δ11B holds that B in calcite predominantly derives from dissolved borate anion in seawater, recent studies of the B content, coordination, and isotopic composition in calcite suggest more complex B incorporation pathways. To provide new insights into these pathways, here we present δ11B of inorganic calcite precipitated from saline solutions of varying pH, calcium and dissolved inorganic carbon (DIC) concentration for which B/Ca data were previously reported by Uchikawa et al. (2015). Results show that calcite δ11B significantly increases with increasing pH and decreases with increasing [Ca2+] and [DIC]. In combination, these experiments show that the difference in δ11B between solid calcite and aqueous borate linearly decreases with increasing calcite precipitation rate. To interpret these data, we present the first application of surface kinetic modeling (SKM) to boron incorporation. The SKM can simultaneously explain rate-dependent B/Ca and δ11B patterns observed in our and previously published inorganic calcite precipitation experiments when both aqueous borate and boric acid contribute to boron in inorganic calcite. If the B incorporation mechanism shown here for inorganic calcite is applicable to biogenic calcite, precipitation rate variations could modify δ11B patterns by changing the contributions of aqueous boric acid and borate to boron in calcite. However, better knowledge of biogenic calcite precipitation mechanisms and rates is needed to assess the importance of this effect for applications of B proxies in biogenic carbonates.

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Henry’s law constant for CO2 in aqueous sodium chloride solutions at 1 atm and sub-zero (Celsius) temperatures


• Henry’s Law constant for CO2 was determined in NaCl solutions at temperatures from −1 to −10 °C.
• CO2 solubility in cold seawater and sea ice-brines is higher than previously estimated.
• Air-sea exchange of CO2 and climate modeling need to revisit the solubility of CO2 at sub-zero temperatures.


The solubility of CO2 in seawater is known to increase at colder temperatures, but few studies have examined the CO2 solubility in seawater and in sea-ice brines at sub-zero (Celsius) temperatures. The thermodynamic Henry’s Law constant (KH) for CO2 in concentrated NaCl solutions was determined for the first time at sub-zero temperatures and salinities resembling those of the cryospheric seawater and sea-ice brine environments in polar and sub-polar oceans. The temperature (T, in Kelvin) dependence of the KH within the temperature and salinity ranges of this study (263 ≤ T ≤ 272 K and 35 ≤ S ≤ 152) is described by the following best-fit equation: ln KH = −2.484 + 2.775 × 10−2(274 − T) − 9.854 × 10−2/(274 − T) − 1.009 × 10−1 ln (274–T). The results show that the general practice, in geochemical and coupled climate‑carbon cycling models, of extrapolating KH values from above-zero to sub-zero temperatures underestimates the solubility of CO2 by up to 19%.

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Environmental controls on pteropod biogeography along the Western Antarctic Peninsula

Pteropods are abundant zooplankton in the Western Antarctic Peninsula (WAP) and important grazers of phytoplankton and prey for higher trophic levels. We analyzed long‐term (1993–2017) trends in summer (January–February) abundance of WAP pteropods in relation to environmental controls (sea ice, sea surface temperature, climate indices, phytoplankton biomass and productivity, and carbonate chemistry) and interspecies dynamics using general linear models. There was no overall directional trend in abundance of thecosomes, Limacina helicina antarctica and Clio pyramidata, throughout the entire WAP, although L. antarctica abundance increased in the slope region and C. pyramidata abundance increased in the South. High L. antarctica abundance was strongly tied to a negative Multivariate El Niño Southern Oscillation Index the previous year. C. pyramidata abundance was best explained by early sea ice retreat 1‐yr prior. Abundance of the gymnosome species, Clione antarctica and Spongiobranchaea australis, increased over the time series, particularly in the slope region. Gymnosome abundance was positively influenced by abundance of their prey, L. antarctica, during the same season, and late sea ice advance 2‐yr prior. These trends indicate a shorter ice season promotes longer periods of open water in spring/summer favoring all pteropod species. Weak relationships were found between pteropod abundance and carbonate chemistry, and no long‐term trend in carbonate parameters was detected. These factors indicate ocean acidification is not presently influencing WAP pteropod abundance. Pteropods are responsive to the considerable environmental variability on both temporal and spatial scales—key for predicting future effects of climate change on regional carbon cycling and plankton trophic interactions.

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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.

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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.

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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.

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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.

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


• 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.


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.

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


• 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.


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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