scholarly journals Impacts of food availability and <i>p</i>CO<sub>2</sub> on planulation, juvenile survival, and calcification of the azooxanthellate scleractinian coral <i>Balanophyllia elegans</i>

2013 ◽  
Vol 10 (11) ◽  
pp. 7599-7608 ◽  
Author(s):  
E. D. Crook ◽  
H. Cooper ◽  
D. C. Potts ◽  
T. Lambert ◽  
A. Paytan
Keyword(s):  
Ocean Acidification ◽  
Feeding Rate ◽  
High Pco2 ◽  
Food Level ◽  
Saturation State ◽  
Skeletal Density ◽  
Juvenile Mortality ◽  
Algal Symbionts ◽  
Aragonite Crystal ◽  
Tropical Reef

Abstract. Ocean acidification, the assimilation of atmospheric CO2 by the oceans that decreases the pH and CaCO3 saturation state (Ω) of seawater, is projected to have severe adverse consequences for calcifying organisms. While strong evidence suggests calcification by tropical reef-building corals containing algal symbionts (zooxanthellae) will decline over the next century, likely responses of azooxanthellate corals to ocean acidification are less well understood. Because azooxanthellate corals do not obtain photosynthetic energy from symbionts, they provide a system for studying the direct effects of acidification on energy available for calcification. The solitary azooxanthellate orange cup coral Balanophyllia elegans often lives in low-pH, upwelled waters along the California coast. In an 8-month factorial experiment, we measured the effects of three pCO2 treatments (410, 770, and 1220 μatm) and two feeding frequencies (3-day and 21-day intervals) on "planulation" (larval release) by adult B. elegans, and on the survival, skeletal growth, and calcification of newly settled juveniles. Planulation rates were affected by food level but not pCO2. Juvenile mortality was highest under high pCO2 (1220 μatm) and low food (21-day intervals). Feeding rate had a greater impact on calcification of B. elegans than pCO2. While net calcification was positive even at 1220 μatm (~3 times current atmospheric pCO2), overall calcification declined by ~25–45%, and skeletal density declined by ~35–45% as pCO2 increased from 410 to 1220 μatm. Aragonite crystal morphology changed at high pCO2, becoming significantly shorter but not wider at 1220 μatm. We conclude that food abundance is critical for azooxanthellate coral calcification, and that B. elegans may be partially protected from adverse consequences of ocean acidification in habitats with abundant heterotrophic food.

scholarly journals Food availability and <i>p</i>CO<sub>2</sub> impacts on planulation, juvenile survival, and calcification of the azooxanthellate scleractinian coral, <i>Balanophyllia elegans</i>

2013 ◽  
Vol 10 (5) ◽  
pp. 7761-7783 ◽  
Author(s):  
E. D. Crook ◽  
H. Cooper ◽  
D. C. Potts ◽  
T. Lambert ◽  
A. Paytan
Keyword(s):  
Ocean Acidification ◽  
Coastal Upwelling ◽  
Food Level ◽  
Juvenile Survival ◽  
High Food ◽  
Saturation State ◽  
Skeletal Density ◽  
Algal Symbionts ◽  
Aragonite Crystal ◽  
Food Conditions

Abstract. Ocean acidification, the assimilation of atmospheric CO2 by the oceans that decreases the pH and CaCO3 saturation state (Ω) of seawater, is projected to have severe consequences for calcifying organisms. Strong evidence suggests that tropical reef-building corals containing algal symbionts (zooxanthellae) will experience dramatic declines in calcification over the next century. The responses of azooxanthellate corals to ocean acidification are less well understood, and because they cannot obtain extra photosynthetic energy from symbionts, they provide a system for studying the direct effects of acidification on the energy available for calcification. The orange cup coral Balanophyllia elegans is a solitary, azooxanthellate scleractinian species common on the California coast where it thrives in the low pH waters of an upwelling regime. During an 8 month study, we addressed the effects of three pCO2 treatments (410, 770, and 1230 μatm) and two feeding frequencies (High Food and Low Food) on adult Balanophyllia elegans planulation (larval release) rates, and on the survival, growth, and calcification of their juvenile offspring. Planulation rates were affected by food level but not pCO2, while juvenile survival was highest under 410 μatm and High Food conditions. Our results suggest that feeding rate has a greater impact on calcification of B. elegans than pCO2. Net calcification was positive even at 1230 μatm (~ 3 times current atmospheric pCO2), although the increase from 410 to 1230 μatm reduced overall calcification by ~ 25–45%, and reduced skeletal density by ~ 35–45%. Higher pCO2 also altered aragonite crystal morphology significantly. We discuss how feeding frequency affects azooxanthellate coral calcification, and how B. elegans may respond to ocean acidification in coastal upwelling waters.

scholarly journals Implications of observed inconsistencies in carbonate chemistry measurements for ocean acidification studies

2012 ◽  
Vol 9 (2) ◽  
pp. 1781-1792 ◽  
Author(s):  
C. J. M. Hoppe ◽  
G. Langer ◽  
S. D. Rokitta ◽  
D. A. Wolf-Gladrow ◽  
B. Rost
Keyword(s):  
Ocean Acidification ◽  
High Pco2 ◽  
Small Scale ◽  
Ecological Data ◽  
Carbonate Chemistry ◽  
Carbonate System ◽  
Saturation State ◽  
Severe Problem ◽  
Important Approach ◽  
Calcite Saturation

Abstract. The growing field of ocean acidification research is concerned with the investigation of organisms' responses to increasing pCO2 values. One important approach in this context is culture work using seawater with adjusted CO2 levels. As aqueous pCO2 is difficult to measure directly in small scale experiments, it is generally calculated from two other measured parameters of the carbonate system (often AT, CT or pH). Unfortunately, the overall uncertainties of measured and subsequently calculated values are often unknown. Especially under high pCO2, this can become a severe problem with respect to the interpretation of physiological and ecological data. In the few datasets from ocean acidification research where all three of these parameters were measured, pCO2 values calculated from AT and CT are typically about 30 % lower (i.e. ~300 μatm at a target pCO2 of 1000 μatm) than those calculated from AT and pH or CT and pH. This study presents and discusses these discrepancies as well as likely consequences for the ocean acidification community. Until this problem is solved, one has to consider that calculated parameters of the carbonate system (e.g. pCO2, calcite saturation state) may not be comparable between studies, and that this may have important implications for the interpretation of CO2 perturbation experiments.

scholarly journals Implications of observed inconsistencies in carbonate chemistry measurements for ocean acidification studies

2012 ◽  
Vol 9 (7) ◽  
pp. 2401-2405 ◽  
Author(s):  
C. J. M. Hoppe ◽  
G. Langer ◽  
S. D. Rokitta ◽  
D. A. Wolf-Gladrow ◽  
B. Rost
Keyword(s):  
Ocean Acidification ◽  
High Pco2 ◽  
Small Scale ◽  
Ecological Data ◽  
Carbonate Chemistry ◽  
Carbonate System ◽  
Saturation State ◽  
Severe Problem ◽  
Important Approach ◽  
Calcite Saturation

Abstract. The growing field of ocean acidification research is concerned with the investigation of organism responses to increasing pCO2 values. One important approach in this context is culture work using seawater with adjusted CO2 levels. As aqueous pCO2 is difficult to measure directly in small-scale experiments, it is generally calculated from two other measured parameters of the carbonate system (often AT, CT or pH). Unfortunately, the overall uncertainties of measured and subsequently calculated values are often unknown. Especially under high pCO2, this can become a severe problem with respect to the interpretation of physiological and ecological data. In the few datasets from ocean acidification research where all three of these parameters were measured, pCO2 values calculated from AT and CT are typically about 30% lower (i.e. ~300 μatm at a target pCO2 of 1000 μatm) than those calculated from AT and pH or CT and pH. This study presents and discusses these discrepancies as well as likely consequences for the ocean acidification community. Until this problem is solved, one has to consider that calculated parameters of the carbonate system (e.g. pCO2, calcite saturation state) may not be comparable between studies, and that this may have important implications for the interpretation of CO2 perturbation experiments.

scholarly journals Response of benthic foraminifera to ocean acidification in their natural sediment environment: a long-term culturing experiment

2014 ◽  
Vol 11 (6) ◽  
pp. 1581-1597 ◽  
Author(s):  
K. Haynert ◽  
J. Schönfeld ◽  
R. Schiebel ◽  
B. Wilson ◽  
J. Thomsen
Keyword(s):  
Ocean Acidification ◽  
Experimental Period ◽  
Organic Content ◽  
High Pco2 ◽  
Natural Sediment ◽  
Size Frequency Distribution ◽  
Saturation State ◽  
Carbonate Production ◽  
Subdominant Species

Abstract. Calcifying foraminifera are expected to be endangered by ocean acidification; however, the response of a complete community kept in natural sediment and over multiple generations under controlled laboratory conditions has not been constrained to date. During 6 months of incubation, foraminiferal assemblages were kept and treated in natural sediment with pCO2-enriched seawater of 430, 907, 1865 and 3247 μatm pCO2. The fauna was dominated by Ammonia aomoriensis and Elphidium species, whereas agglutinated species were rare. After 6 months of incubation, pore water alkalinity was much higher in comparison to the overlying seawater. Consequently, the saturation state of Ωcalc was much higher in the sediment than in the water column in nearly all pCO2 treatments and remained close to saturation. As a result, the life cycle (population density, growth and reproduction) of living assemblages varied markedly during the experimental period, but was largely unaffected by the pCO2 treatments applied. According to the size–frequency distribution, we conclude that foraminifera start reproduction at a diameter of 250 μm. Mortality of living Ammonia aomoriensis was unaffected, whereas size of large and dead tests decreased with elevated pCO2 from 285 μm (pCO2 from 430 to 1865 μatm) to 258 μm (pCO2 3247 μatm). The total organic content of living Ammonia aomoriensis has been determined to be 4.3% of CaCO3 weight. Living individuals had a calcium carbonate production rate of 0.47 g m−2 a−1, whereas dead empty tests accumulated a rate of 0.27 g m−2 a−1. Although Ωcalc was close to 1, approximately 30% of the empty tests of Ammonia aomoriensis showed dissolution features at high pCO2 of 3247 μatm during the last 2 months of incubation. In contrast, tests of the subdominant species, Elphidium incertum, stayed intact. Our results emphasize that the sensitivity to ocean acidification of the endobenthic foraminifera Ammonia aomoriensis in their natural sediment habitat is much lower compared to the experimental response of specimens isolated from the sediment.

scholarly journals Ocean acidification affects productivity but not the severity of thermal bleaching in some tropical corals

2015 ◽  
Vol 73 (3) ◽  
pp. 715-726 ◽  
Author(s):  
Sam H. C. Noonan ◽  
Katharina E. Fabricius
Keyword(s):  
Ocean Acidification ◽  
Coral Bleaching ◽  
Dissolved Inorganic Carbon ◽  
Laboratory Data ◽  
Elevated Pco2 ◽  
High Pco2 ◽  
Quantum Yields ◽  
Saturation State ◽  
Thermal Bleaching ◽  
Tank Experiment

Abstract Increasing carbon dioxide (CO2) emissions are raising sea surface temperature (SST) and causing ocean acidification (OA). While higher SST increases the frequency of mass coral bleaching events, it is unclear how OA will interact to affect this process. In this study, we combine in situ bleaching surveys around three tropical CO2 seeps with a 2-month two-factor (CO2 and temperature) tank experiment to investigate how OA and SST in combination will affect the bleaching susceptibility of tropical reef corals. Surveys at CO2 seep and control sites during a minor regional bleaching event gave little indication that elevated pCO2 influenced the bleaching susceptibility of the wider coral community, the four most common coral families (Acroporidae, Faviidae, Pocilloporidae, or Poritidae), or the thermally sensitive coral species Seriatopora hystrix. In the tank experiment, sublethal bleaching was observed at 31°C after 5 d in S. hystrix and 12 d in Acropora millepora, whereas controls (28°C) did not bleach. None of the measured proxies for coral bleaching was negatively affected by elevated pCO2 at pHT 7.79 (vs. 7.95 pHT in controls), equivalent to ∼780 µatm pCO2 and an aragonite saturation state of 2.5. On the contrary, high pCO2 benefitted some photophysiological measures (although temperature effects were much stronger than CO2 effects): maximum photosystem II quantum yields and light-limited electron transport rates increased in both species at high pCO2, whereas gross photosynthesis and pigment concentrations increased in S. hystrix at high pCO2. The field and laboratory data in combination suggest that OA levels up to a pHT of 7.8 will have little effect on the sensitivity of tropical corals to thermal bleaching. Indeed, some species appear to be able to utilize the more abundant dissolved inorganic carbon to increase productivity; however, these gains offset only a small proportion of the massive bleaching-related energy losses during thermal stress.

scholarly journals Effect of ocean acidification on otolith development in larvae of a tropical marine fish

2011 ◽  
Vol 8 (2) ◽  
pp. 2329-2356 ◽  
Author(s):  
P. L. Munday ◽  
V. Hernaman ◽  
D. L. Dixson ◽  
S. R. Thorrold
Keyword(s):  
Ocean Acidification ◽  
Larval Fish ◽  
Ph Regulation ◽  
Elevated Pco2 ◽  
High Pco2 ◽  
Saturation State ◽  
Amphiprion Percula ◽  
Carbonate Ions ◽  
Left And Right ◽  
Extreme Treatment

Abstract. Calcification in many invertebrate species is predicted to decline due to ocean acidification. The potential effects of elevated pCO2 and reduced carbonate saturation state on other species, such as fish, are less well understood. Fish otoliths (earbones) are composed of aragonite, and thus, might be susceptible to either the reduced availability of carbonate ions in seawater at low pH, or to changes in extracellular concentrations of bicarbonate and carbonate ions caused by acid-base regulation in fish exposed to high pCO2. We reared larvae of the clownfish Amphiprion percula from hatching to settlement at three pHNBS and pCO2 levels (control: pH 8.15 and 404 μatm CO2; intermediate: pH 7.8 and 1050 μatm CO2; extreme: pH 7.6 and 1721 μatm CO2) to test the possible effects of ocean acidification on otolith development. There was no effect of the intermediate treatment (pH 7.8 and 1050 μatm CO2) on otolith size, shape, symmetry between left and right otoliths, or otolith elemental chemistry, compared with controls. However, in the more extreme treatment (pH 7.6 and 1721 μatm CO2) otolith area and maximum length were larger than controls, although no other traits were affected. Our results support the hypothesis that pH regulation in the otolith endolymph of fish exposed to elevated pCO2 can lead to increased precipitation of CaCO3 in otoliths of larval fish, as proposed by an earlier study, however, our results also show that sensitivity varies considerably among species. Importantly, our results suggest that otolith development in clownfishes is robust to even the more pessimistic changes in ocean chemistry predicted to occur by 2100.

scholarly journals Effect of ocean acidification on otolith development in larvae of a tropical marine fish

2011 ◽  
Vol 8 (6) ◽  
pp. 1631-1641 ◽  
Author(s):  
P. L. Munday ◽  
V. Hernaman ◽  
D. L. Dixson ◽  
S. R. Thorrold
Keyword(s):  
Ocean Acidification ◽  
Elevated Co2 ◽  
Larval Fish ◽  
Ph Regulation ◽  
High Pco2 ◽  
Saturation State ◽  
Amphiprion Percula ◽  
Carbonate Ions ◽  
Left And Right ◽  
Extreme Treatment

Abstract. Calcification in many invertebrate species is predicted to decline due to ocean acidification. The potential effects of elevated CO2 and reduced carbonate saturation state on other species, such as fish, are less well understood. Fish otoliths (earbones) are composed of aragonite, and thus, might be susceptible to either the reduced availability of carbonate ions in seawater at low pH, or to changes in extracellular concentrations of bicarbonate and carbonate ions caused by acid-base regulation in fish exposed to high pCO2. We reared larvae of the clownfish Amphiprion percula from hatching to settlement at three pHNBS and pCO2 levels (control: ~pH 8.15 and 404 μatm CO2; intermediate: pH 7.8 and 1050 μatm CO2; extreme: pH 7.6 and 1721 μatm CO2) to test the possible effects of ocean acidification on otolith development. There was no effect of the intermediate treatment (pH 7.8 and 1050 μatm CO2) on otolith size, shape, symmetry between left and right otoliths, or otolith elemental chemistry, compared with controls. However, in the more extreme treatment (pH 7.6 and 1721 μatm CO2) otolith area and maximum length were larger than controls, although no other traits were significantly affected. Our results support the hypothesis that pH regulation in the otolith endolymph can lead to increased precipitation of CaCO3 in otoliths of larval fish exposed to elevated CO2, as proposed by an earlier study, however, our results also show that sensitivity varies considerably among species. Importantly, our results suggest that otolith development in clownfishes is robust to even the more pessimistic changes in ocean chemistry predicted to occur by 2100.

scholarly journals Effects of ocean acidification on calcification of symbiont-bearing reef foraminifers

2011 ◽  
Vol 8 (8) ◽  
pp. 2089-2098 ◽  
Author(s):  
K. Fujita ◽  
M. Hikami ◽  
A. Suzuki ◽  
A. Kuroyanagi ◽  
K. Sakai ◽  
...  
Keyword(s):  
Coral Reefs ◽  
Ocean Acidification ◽  
Elevated Pco2 ◽  
Ion Concentration ◽  
Saturation State ◽  
Carbonate Concentration ◽  
Algal Symbionts ◽  
Algal Symbiont ◽  
Coral Reef Ecosystems ◽  
Fertilization Effects

Abstract. Ocean acidification (decreases in carbonate ion concentration and pH) in response to rising atmospheric pCO2 is generally expected to reduce rates of calcification by reef calcifying organisms, with potentially severe implications for coral reef ecosystems. Large, algal symbiont-bearing benthic foraminifers, which are important primary and carbonate producers in coral reefs, produce high-Mg calcite shells, whose solubility can exceed that of aragonite produced by corals, making them the "first responder" in coral reefs to the decreasing carbonate saturation state of seawater. Here we report results of culture experiments performed to assess the effects of ongoing ocean acidification on the calcification of symbiont-bearing reef foraminifers using a high-precision pCO2 control system. Living clone individuals of three foraminiferal species (Baculogypsina sphaerulata, Calcarina gaudichaudii, and Amphisorus hemprichii) were subjected to seawater at five pCO2 levels from 260 to 970 μatm. Cultured individuals were maintained for about 12 weeks in an indoor flow-through system under constant water temperature, light intensity, and photoperiod. After the experiments, the shell diameter and weight of each cultured specimen were measured. Net calcification of B. sphaerulata and C. gaudichaudii, which secrete a hyaline shell and host diatom symbionts, increased under intermediate levels of pCO2 (580 and/or 770 μatm) and decreased at a higher pCO2 level (970 μatm). Net calcification of A. hemprichii, which secretes a porcelaneous shell and hosts dinoflagellate symbionts, tended to decrease at elevated pCO2. Observed different responses between hyaline and porcelaneous species are possibly caused by the relative importance of elevated pCO2, which induces CO2 fertilization effects by algal symbionts, versus associated changes in seawater carbonate chemistry, which decreases a carbonate concentration. Our findings suggest that ongoing ocean acidification might favor symbiont-bearing reef foraminifers with hyaline shells at intermediate pCO2 levels (580 to 770 μatm) but be unfavorable to those with either hyaline or porcelaneous shells at higher pCO2 levels (near 1000 μatm).

scholarly journals Thermal stress reduces pocilloporid coral resilience to ocean acidification by impairing control over calcifying fluid chemistry

2021 ◽  
Vol 7 (2) ◽  
pp. eaba9958
Author(s):  
Maxence Guillermic ◽  
Louise P. Cameron ◽  
Ilian De Corte ◽  
Sambuddha Misra ◽  
Jelle Bijma ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Ocean Acidification ◽  
Pocillopora Damicornis ◽  
Carbonate Chemistry ◽  
Negative Interaction ◽  
Saturation State ◽  
Stylophora Pistillata ◽  
Coral Calcification ◽  
Influence Of Temperature On ◽  
Different Time Scales

The combination of thermal stress and ocean acidification (OA) can more negatively affect coral calcification than an individual stressors, but the mechanism behind this interaction is unknown. We used two independent methods (microelectrode and boron geochemistry) to measure calcifying fluid pH (pHcf) and carbonate chemistry of the corals Pocillopora damicornis and Stylophora pistillata grown under various temperature and pCO2 conditions. Although these approaches demonstrate that they record pHcf over different time scales, they reveal that both species can cope with OA under optimal temperatures (28°C) by elevating pHcf and aragonite saturation state (Ωcf) in support of calcification. At 31°C, neither species elevated these parameters as they did at 28°C and, likewise, could not maintain substantially positive calcification rates under any pH treatment. These results reveal a previously uncharacterized influence of temperature on coral pHcf regulation—the apparent mechanism behind the negative interaction between thermal stress and OA on coral calcification.

scholarly journals Metabolic cost of calcification in bivalve larvae under experimental ocean acidification

2016 ◽  
Vol 74 (4) ◽  
pp. 941-954 ◽  
Author(s):  
Christina A. Frieder ◽  
Scott L. Applebaum ◽  
T.-C. Francis Pan ◽  
Dennis Hedgecock ◽  
Donal T. Manahan
Keyword(s):  
Ocean Acidification ◽  
Climate Change Impacts ◽  
Metabolic Cost ◽  
Shell Formation ◽  
Metabolic Demand ◽  
Shell Size ◽  
Saturation State ◽  
Shell Mass ◽  
Energy Limitation ◽  
Endogenous Reserves

Abstract Physiological increases in energy expenditure frequently occur in response to environmental stress. Although energy limitation is often invoked as a basis for decreased calcification under ocean acidification, energy-relevant measurements related to this process are scant. In this study we focus on first-shell (prodissoconch I) formation in larvae of the Pacific oyster, Crassostrea gigas. The energy cost of calcification was empirically derived to be ≤ 1.1 µJ (ng CaCO3)−1. Regardless of the saturation state of aragonite (2.77 vs. 0.77), larvae utilize the same amount of total energy to complete first-shell formation. Even though there was a 56% reduction of shell mass and an increase in dissolution at aragonite undersaturation, first-shell formation is not energy limited because sufficient endogenous reserves are available to meet metabolic demand. Further studies were undertaken on larvae from genetic crosses of pedigreed lines to test for variance in response to aragonite undersaturation. Larval families show variation in response to ocean acidification, with loss of shell size ranging from no effect to 28%. These differences show that resilience to ocean acidification may exist among genotypes. Combined studies of bioenergetics and genetics are promising approaches for understanding climate change impacts on marine organisms that undergo calcification.

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