scholarly journals Key Arctic pelagic mollusc (<i>Limacina helicina</i>) threatened by ocean acidification

2009 ◽  
Vol 6 (1) ◽  
pp. 2523-2537 ◽  
Author(s):  
S. Comeau ◽  
G. Gorsky ◽  
R. Jeffree ◽  
J.-L. Teyssié ◽  
J.-P. Gattuso
Keyword(s):  
Ocean Acidification ◽  
Ph Value ◽  
Food Resource ◽  
Arctic Ecosystems ◽  
Carbonate Chemistry ◽  
High Co2 ◽  
Key Species ◽  
Limacina Helicina ◽  
Ph Conditions ◽  
The Impact

Abstract. Thecosome pteropods (shelled pelagic molluscs) can play an important role in the food web of various ecosystems and play a key role in the cycling of carbon and carbonate. Since they harbor an aragonitic shell, they could be very sensitive to ocean acidification driven by the increase of anthropogenic CO2 emissions. The impact of changes in the carbonate chemistry was investigated on Limacina helicina, a key species of Arctic ecosystems. Pteropods were kept in culture under controlled pH conditions corresponding to pCO2 levels of 350 and 760 μatm. Calcification was estimated using a fluorochrome and the radioisotope 45Ca. It exhibits a 28% decrease at the pH value expected for 2100 compared to the present pH value. This result supports the concern for the future of pteropods in a high-CO2 world, as well as of those species dependent upon them as a food resource. A decline of their populations would likely cause dramatic changes to the structure, function and services of polar ecosystems.

scholarly journals Impact of ocean acidification on a key Arctic pelagic mollusc (<i>Limacina helicina</i>)

2009 ◽  
Vol 6 (9) ◽  
pp. 1877-1882 ◽  
Author(s):  
S. Comeau ◽  
G. Gorsky ◽  
R. Jeffree ◽  
J.-L. Teyssié ◽  
J.-P. Gattuso
Keyword(s):  
Ocean Acidification ◽  
Ph Value ◽  
Food Resource ◽  
Arctic Ecosystems ◽  
Carbonate Chemistry ◽  
High Co2 ◽  
Key Species ◽  
Limacina Helicina ◽  
Ph Conditions ◽  
The Impact

Abstract. Thecosome pteropods (shelled pelagic molluscs) can play an important role in the food web of various ecosystems and play a key role in the cycling of carbon and carbonate. Since they harbor an aragonitic shell, they could be very sensitive to ocean acidification driven by the increase of anthropogenic CO2 emissions. The impact of changes in the carbonate chemistry was investigated on Limacina helicina, a key species of Arctic ecosystems. Pteropods were kept in culture under controlled pH conditions corresponding to pCO2 levels of 350 and 760 μatm. Calcification was estimated using a fluorochrome and the radioisotope 45Ca. It exhibits a 28% decrease at the pH value expected for 2100 compared to the present pH value. This result supports the concern for the future of pteropods in a high-CO2 world, as well as of those species dependent upon them as a food resource. A decline of their populations would likely cause dramatic changes to the structure, function and services of polar ecosystems.

scholarly journals Variation in brachiopod microstructure and isotope geochemistry under low pH–ocean acidification–conditions

2018 ◽  
Author(s):  
Facheng Ye ◽  
Hana Jurikova ◽  
Lucia Angiolini ◽  
Uwe Brand ◽  
Gaia Crippa ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Ocean Acidification ◽  
Isotope Geochemistry ◽  
Shell Growth ◽  
Low Ph ◽  
Secondary Layer ◽  
Ph Conditions ◽  
One Year ◽  
The Impact ◽  
Δ13c And Δ18o

Abstract. Throughout the last few decades and in the near future CO2–induced ocean acidification is potentially a big threat to marine calcite-shelled animals (e.g., brachiopods, bivalves, corals and gastropods). Despite the great number of studies focusing on the effects of acidification on shell growth, metabolism, shell dissolution and shell repair, the consequences on biomineral formation remain poorly understood, and only few studies addressed contemporarily the impact of acidification on shell microstructure and geochemistry. In this study, a detailed microstructure and stable isotope geochemistry investigation was performed on nine adult brachiopod specimens of Magellania venosa (Dixon, 1789), grown in the natural environment as well as in controlled culturing experiments at different pH conditions (ranging 7.35 to 8.15 ± 0.05) over different time intervals (214 to 335 days). Details of shell microstructural features, such as thickness of the primary layer, density and size of endopunctae and morphology of the basic structural unit of the secondary layer were analysed using scanning electron microscopy (SEM). Stable isotope compositions (δ13C and δ18O) were tested from the secondary shell layer along shell ontogenetic increments in both dorsal and ventral valves. Based on our comprehensive dataset, we observed that, under low pH conditions, M. venosa produced a more organic-rich shell with higher density of and larger endopunctae, and smaller secondary layer fibres, when subjected to about one year of culturing. Also, increasingly negative δ13C and δ18O values are recorded by the shell produced during culturing and are related to the CO2–source in the culture setup. Both the microstructural changes and the stable isotope results are similar to observations on brachiopods from the fossil record and strongly support the value of brachiopods as robust archives of proxies for studying ocean acidification events in the geologic past.

scholarly journals Perturbation experiments to investigate the impact of ocean acidification: approaches and software tools

2009 ◽  
Vol 6 (2) ◽  
pp. 4413-4439 ◽  
Author(s):  
J.-P. Gattuso ◽  
H. Lavigne
Keyword(s):  
Ocean Acidification ◽  
Software Package ◽  
Biological Response ◽  
Experimental Manipulation ◽  
Carbonate Chemistry ◽  
R Software ◽  
Seawater Chemistry ◽  
Seawater Carbonate Chemistry ◽  
Gas Bubbling ◽  
The Impact

Abstract. Although future changes in the seawater carbonate chemistry are well constrained, their impact on marine organisms and ecosystems remains poorly known. The biological response to ocean acidification is a recent field of research as most purposeful experiments have only been carried out in the late 1990s. The potentially dire consequences of ocean acidification attract scientists and students with a limited knowledge of the carbonate chemistry and its experimental manipulation. Hence, some guidelines on carbonate chemistry manipulations may be helpful for the growing ocean acidification community to maintain comparability. Perturbation experiments are one of the key approaches used to investigate the biological response to elevated pCO2. They are based on measurements of physiological or metabolic processes in organisms and communities exposed to seawater with normal or altered carbonate chemistry. Seawater chemistry can be manipulated in different ways depending on the facilities available and on the question being addressed. The goal of this paper is (1) to examine the benefits and drawbacks of various manipulation techniques and (2) to describe a new version of the R software package seacarb which includes new functions aimed at assisting the design of ocean acidification perturbation experiments. Three approaches closely mimic the on-going and future changes in the seawater carbonate chemistry: gas bubbling, addition of high-CO2 seawater as well as combined additions of acid and bicarbonate and/or carbonate.

scholarly journals Shell dissolution observed in <i>Limacina helicina antarctica</i> from the Ross Sea, Antarctica: paired shell characteristics and in situ seawater chemistry

2016 ◽  
Author(s):  
Kevin M. Johnson ◽  
Umihiko Hoshijima ◽  
Cailan S. Sugano ◽  
Alice T. Nguyen ◽  
Gretchen E. Hofmann
Keyword(s):  
Southern Ocean ◽  
Ocean Acidification ◽  
Field Study ◽  
Ross Sea ◽  
Carbonate Chemistry ◽  
Active Dissolution ◽  
In Situ Conditions ◽  
Single Station ◽  
Limacina Helicina

Abstract. The euthecosome (shelled) Antarctic pteropod, Limacina helicina antarctica, is a dominant member of the Southern Ocean macrozooplankton community, and due to its aragonitic shell, is thought to be particularly vulnerable to ocean acidification and under-saturation conditions that are predicted in the future. Notably, pteropods in surface waters and near the continental shelf in the Ross Sea are highly vulnerable as these regions are predicted to be seasonally under-saturated within 2–3 decades. Carbonate chemistry data are rare for this region and here we present the results of a 6-week field study and report patterns of dissolution of juvenile pteropods along with carbonate chemistry of seawater at the time of collection. Conducted in McMurdo Sound in the south Ross Sea in the Pacific sector of the Southern Ocean, L. h. antarctica was successfully collected in plankton tows through the fast sea ice at a single station at 50 m. During the 6-week field study, ocean pH was relatively stable, ranging from 7.988 in October to 8.029 by early December. Calculated saturation states for aragonite (Ωarag) over the 6-week study period ranged from 1.16 to 1.24. Pteropods collected at each sampling time point were prepared for SEM and analysis revealed that roughly 63 % of the shells displayed some degree of shell irregularities suggesting that active dissolution of the aragonitic shell was ongoing under in situ conditions. These results add to the accumulating evidence that shelled pteropods of the Southern Ocean are experiencing aragonite under-saturation events in the present-day that lead to a majority of individuals displaying shell dissolution. Predicted changes to the carbonate system in the Southern Ocean from ocean acidification will likely expand the intensity and duration of these under-saturation events, increasing the need to better understand how pteropods will fare in response to ocean acidification.

scholarly journals Ambient pH regulates secretion of lipases in Malassezia furfur

Microbiology ◽  
2020 ◽  
Vol 166 (3) ◽  
pp. 288-295 ◽  
Author(s):  
Weerapong Juntachai ◽  
Athipat Chaichompoo ◽  
Sittinan Chanarat
Keyword(s):  
Ph Value ◽  
The Body ◽  
Morphological Alteration ◽  
Human Gut ◽  
Dynamic Changes ◽  
Ph Conditions ◽  
Intravascular Catheters ◽  
Major Factors ◽  
The Impact ◽  
External Ph

Malassezia is a lipophilic cutaneous commensal yeast and associated with various skin disorders. The yeast also causes bloodstream infection via intravascular catheters and can be detected even in human gut microbiota. Ambient pH is one of the major factors that affect the physiology and metabolism of several pathogenic microorganisms. Although dynamic changes of pH environment in different parts of the body is a great challenge for Malassezia to confront, the role that ambient pH plays in Malassezia is largely unknown. In this study, we investigated the impact of ambient pH on physiology and expression of lipases in M. furfur grown under different pH conditions. The yeast was able to grow in media ranging from pH 4 to 10 without morphological alteration. Elevation in pH value enhanced the extracellular lipase activity but decreased that of intracellular lipase. The qPCR results revealed that a set of functional lipase genes, LIP3-6, were constitutively expressed regardless of pH conditions or exposure time. Based on the data, we conclude that the external pH plays a promotional role in the secretion of lipases but exerts less effect on transcription of the genes and morphology in M. furfur.

scholarly journals Seagrass beds as ocean acidification refuges for mussels? High resolution measurements of <i>p</i>CO<sub>2</sub> and O<sub>2</sub> in a <i>Zostera marina</i> and <i>Mytilus edulis</i> mosaic habitat

2015 ◽  
Vol 12 (14) ◽  
pp. 11423-11461 ◽  
Author(s):  
V. Saderne ◽  
P. Fietzek ◽  
S. Aßmann ◽  
A. Körtzinger ◽  
C. Hiebenthal
Keyword(s):  
High Resolution ◽  
Ocean Acidification ◽  
High Pco2 ◽  
Seagrass Beds ◽  
Carbonate Chemistry ◽  
Calcium Carbonates ◽  
Positive Side ◽  
Chemical Conditions ◽  
Technological Limitations ◽  
The Impact

Abstract. It has been speculated that macrophytes beds might act as a refuge for calcifiers from ocean acidification. In the shallow nearshores of the western Kiel Bay (Baltic Sea), mussel and seagrass beds are interlacing, forming a mosaic habitat. Naturally, the diverse physiological activities of seagrasses and mussels are affected by seawater carbonate chemistry and they locally modify it in return. Calcification by shellfishes is sensitive to seawater acidity; therefore the photosynthetic activity of seagrasses in confined shallow waters creates favorable chemical conditions to calcification at daytime but turn the habitat less favorable or even corrosive to shells at night. In contrast, mussel respiration releases CO2, turning the environment more favorable for photosynthesis by adjacent seagrasses. At the end of summer, these dynamics are altered by the invasion of high pCO2/low O2 coming from the deep water of the Bay. However, it is in summer that mussel spats settle on the leaves of seagrasses until migrating to the permanent habitat where they will grow adult. These early life phases (larvae/spats) are considered as most sensitive with regard to seawater acidity. So far, the dynamics of CO2 have never been continuously measured during this key period of the year, mostly due to the technological limitations. In this project we used a combination of state-of-the-art technologies and discrete sampling to obtain high-resolution time-series of pCO2 and O2 at the interface between a seagrass and a mussel patch in Kiel Bay in August and September 2013. From these, we derive the entire carbonate chemistry using statistical models. We found the monthly average pCO2 more than 50 % (approx. 640 μatm for August and September) above atmospheric equilibrium right above the mussel patch together with large diel variations of pCO2 within 24 h: 887 ± 331 μatm in August and 742 ± 281 μatm in September (mean ± SD). We observed important daily corrosiveness for calcium carbonates (Ωarag and Ωcalc < 1) centered on sunrise. On the positive side, the investigated habitat never suffered from hypoxia during the study period. We emphasize the need for more experiments on the impact of these acidic conditions on (juvenile) mussels with a focus on the distinct day-night variations observed.

scholarly journals Variation in brachiopod microstructure and isotope geochemistry under low-pH–ocean acidification conditions

2019 ◽  
Vol 16 (2) ◽  
pp. 617-642 ◽  
Author(s):  
Facheng Ye ◽  
Hana Jurikova ◽  
Lucia Angiolini ◽  
Uwe Brand ◽  
Gaia Crippa ◽  
...  
Keyword(s):  
Stable Isotope ◽  
Ocean Acidification ◽  
Isotope Geochemistry ◽  
Shell Growth ◽  
Low Ph ◽  
Secondary Layer ◽  
Ph Conditions ◽  
Set Up ◽  
The Impact ◽  
Δ13c And Δ18o

Abstract. In the last few decades and in the near future CO2-induced ocean acidification is potentially a big threat to marine calcite-shelled animals (e.g. brachiopods, bivalves, corals and gastropods). Despite the great number of studies focusing on the effects of acidification on shell growth, metabolism, shell dissolution and shell repair, the consequences for biomineral formation remain poorly understood. Only a few studies have addressed the impact of ocean acidification on shell microstructure and geochemistry. In this study, a detailed microstructure and stable isotope geochemistry investigation was performed on nine adult brachiopod specimens of Magellania venosa (Dixon, 1789). These were grown in the natural environment as well as in controlled culturing experiments under different pH conditions (ranging from 7.35 to 8.15±0.05) over different time intervals (214 to 335 days). Details of shell microstructural features, such as thickness of the primary layer, density and size of endopunctae and morphology of the basic structural unit of the secondary layer were analysed using scanning electron microscopy. Stable isotope compositions (δ13C and δ18O) were tested from the secondary shell layer along shell ontogenetic increments in both dorsal and ventral valves. Based on our comprehensive dataset, we observed that, under low-pH conditions, M. venosa produced a more organic-rich shell with higher density of and larger endopunctae, and smaller secondary layer fibres. Also, increasingly negative δ13C and δ18O values are recorded by the shell produced during culturing and are related to the CO2 source in the culture set-up. Both the microstructural changes and the stable isotope results are similar to observations on brachiopods from the fossil record and strongly support the value of brachiopods as robust archives of proxies for studying ocean acidification events in the geologic past.

scholarly journals Technical Note: Approaches and software tools to investigate the impact of ocean acidification

2009 ◽  
Vol 6 (10) ◽  
pp. 2121-2133 ◽  
Author(s):  
J.-P. Gattuso ◽  
H. Lavigne
Keyword(s):  
Ocean Acidification ◽  
Biological Response ◽  
Experimental Manipulation ◽  
Technical Note ◽  
Carbonate Chemistry ◽  
R Software ◽  
Seawater Chemistry ◽  
Seawater Carbonate Chemistry ◽  
Gas Bubbling ◽  
The Impact

Abstract. Although future changes in the seawater carbonate chemistry are well constrained, their impact on marine organisms and ecosystems remains poorly known. The biological response to ocean acidification is a recent field of research as most purposeful experiments have only been carried out in the late 1990s. The potentially dire consequences of ocean acidification attract scientists and students with a limited knowledge of the carbonate chemistry and its experimental manipulation. Hence, some guidelines on carbonate chemistry manipulations may be helpful for the growing ocean acidification community to maintain comparability. Perturbation experiments are one of the key approaches used to investigate the biological response to elevated pCO2. They are based on measurements of physiological or metabolic processes in organisms and communities exposed to seawater with normal or altered carbonate chemistry. Seawater chemistry can be manipulated in different ways depending on the facilities available and on the question being addressed. The goal of this paper is (1) to examine the benefits and drawbacks of various manipulation techniques and (2) to describe a new version of the R software package seacarb which includes new functions aimed at assisting the design of ocean acidification perturbation experiments. Three approaches closely mimic the on-going and future changes in the seawater carbonate chemistry: gas bubbling, addition of high-CO2 seawater as well as combined additions of acid and bicarbonate and/or carbonate.

scholarly journals Measuring gross and net calcification of a reef coral under ocean acidification conditions: methodological considerations

2012 ◽  
Vol 9 (7) ◽  
pp. 8241-8272 ◽  
Author(s):  
S. Cohen ◽  
M. Fine
Keyword(s):  
Ocean Acidification ◽  
Reef Coral ◽  
Total Alkalinity ◽  
Carbonate Chemistry ◽  
Stylophora Pistillata ◽  
Realistic Assessment ◽  
Ph Conditions ◽  
Low Sensitivity ◽  
Methodological Considerations ◽  
Projected Changes

Abstract. Ongoing ocean acidification (OA) is rapidly altering carbonate chemistry in the oceans. The projected changes will likely have deleterious consequences for coral reefs by negatively affecting their growth. Nonetheless, diverse responses of reef-building corals calcification to OA hinder our ability to decipher reef susceptibility to elevated pCO2. Some of the inconsistencies between studies originate in measuring net calcification (NC), which does not always consider the proportions of the "real" (gross) calcification (GC) and gross dissolution in the observed response. Here we show that microcolonies of Stylophora pistillata (entirely covered by tissue), incubated under normal (8.2) and reduced (7.6) pH conditions for 16 months, survived and added new skeletal CaCO3, despite low (1.25) Ωarg conditions. Moreover, corals maintained their NC and GC rates under reduced (7.6) pH conditions and displayed positive NC rates at the low-end (7.3) pH treatment while bare coral skeleton underwent marked dissolution. Our findings suggest that S. pistillata may fall into the "low sensitivity" group with respect to OA and that their overlying tissue may be a key determinant in setting their tolerance to reduced pH by limiting dissolution and allowing them to calcify. This study is the first to measure GC and NC rates for a tropical scleractinian corals under OA conditions. We provide a detailed, realistic assessment of the problematic nature of previously accepted methods for measuring calcification (total alkalinity and 45Ca).

scholarly journals Ocean pH fluctuations affect mussel larvae at key developmental transitions

2018 ◽  
Vol 285 (1893) ◽  
pp. 20182381 ◽  
Author(s):  
L. Kapsenberg ◽  
A. Miglioli ◽  
M. C. Bitter ◽  
E. Tambutté ◽  
R. Dumollard ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Larval Development ◽  
Shell Growth ◽  
Larval Shell ◽  
Abnormal Development ◽  
Life History Stage ◽  
Carbonate Chemistry ◽  
Developmental Processes ◽  
Seawater Chemistry ◽  
The Impact

Coastal marine ecosystems experience dynamic fluctuations in seawater carbonate chemistry. The importance of this variation in the context of ocean acidification requires knowing what aspect of variability biological processes respond to. We conducted four experiments (ranging from 3 to 22 days) with different variability regimes (pH T 7.4–8.1) assessing the impact of diel fluctuations in carbonate chemistry on the early development of the mussel Mytilus galloprovincialis . Larval shell growth was consistently correlated to mean exposures, regardless of variability regimes, indicating that calcification responds instantaneously to seawater chemistry. Larval development was impacted by timing of exposure, revealing sensitivity of two developmental processes: development of the shell field, and transition from the first to the second larval shell. Fluorescent staining revealed developmental delay of the shell field at low pH, and abnormal development thereof was correlated with hinge defects in D-veligers. This study shows, for the first time, that ocean acidification affects larval soft-tissue development, independent from calcification. Multiple developmental processes additively underpin the teratogenic effect of ocean acidification on bivalve larvae. These results explain why trochophores are the most sensitive life-history stage in marine bivalves and suggest that short-term variability in carbonate chemistry can impact early larval development.

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