scholarly journals Alkalinity cycling and carbonate chemistry decoupling in seagrass mystify processes of acidification mitigation

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Cale A. Miller ◽  
Amanda L. Kelley
Keyword(s):  
Tidal Mixing ◽  
Limited Capacity ◽  
Freshwater Input ◽  
Carbonate Chemistry ◽  
Carbonate System ◽  
Saturation State ◽  
Adverse Conditions ◽  
Pool Result ◽  
In Situ Observations

AbstractThe adverse conditions of acidification on sensitive marine organisms have led to the investigation of bioremediation methods as a way to abate local acidification. This phytoremediation, by macrophytes, is expected to reduce the severity of acidification in nearshore habitats on short timescales. Characterizing the efficacy of phytoremediation can be challenging as residence time, tidal mixing, freshwater input, and a limited capacity to fully constrain the carbonate system can lead to erroneous conclusions. Here, we present in situ observations of carbonate chemistry relationships to seagrass habitats by comparing dense (DG), patchy (PG), and no grass (NG) Zostera marina pools in the high intertidal experiencing intermittent flooding. High-frequency measurements of pH, alkalinity (TA), and total-CO2 elucidate extreme diel cyclicity in all parameters. The DG pool displayed frequent decoupling between pH and aragonite saturation state (Ωarg) suggesting pH-based inferences of acidification remediation by seagrass can be misinterpreted as pH and Ωarg can be independent stressors for some bivalves. Estimates show the DG pool had an integrated ΔTA of 550 μmol kg−1 over a 12 h period, which is ~ 60% > the PG and NG pools. We conclude habitats with mixed photosynthesizers (i.e., PG pool) result in less decoupling between pH and Ωarg.

scholarly journals Alkalinity Cycling And Carbonate Chemistry Decoupling in Seagrass Mystify Processes of Acidification Mitigation

2021 ◽  
Author(s):  
Cale A. Miller ◽  
Amanda L. Kelley
Keyword(s):  
High Frequency ◽  
Tidal Mixing ◽  
Limited Capacity ◽  
Freshwater Input ◽  
Carbonate Chemistry ◽  
Carbonate System ◽  
Saturation State ◽  
Adverse Conditions ◽  
Pool Result

Abstract The adverse conditions of acidification on sensitive marine organisms has led to the investigation of bioremediation methods as a way to abate local acidification. This phytoremediation, by macrophytes, is expected to reduce the severity of acidification in nearshore habitats on short timescales. Characterizing the efficacy of phytoremediation can be challenging as residence time, tidal mixing, freshwater input, and a limited capacity to fully constrain the carbonate system can lead to erroneous conclusions. Here, we present in situ observations of carbonate chemistry relationships to seagrass habitats by comparing dense (DG), patchy (PG), and no grass (NG) Zostera marina pools in the high intertidal experiencing intermittent flooding. High-frequency measurements of pH, alkalinity (TA), and total-CO2 elucidate extreme diel cyclicity in all parameters. The DG pool displayed frequent decoupling between pH and aragonite saturation state (Ωarg) suggesting pH-based inferences of acidification remediation by seagrass can be misinterpreted as pH and Ωarg can be independent stressors for some bivalves. Estimates show the DG pool had an integrated ΔTA of 550 μmol kg-1 over a 12 h period, which is ~60 % > the PG and NG pools. We conclude habitats with mixed photosynthesizes (i.e., PG pool) result in less decoupling between pH and Ωarg.

scholarly journals Natural ocean acidification at Papagayo upwelling system (North Pacific Costa Rica): implications for reef development

2017 ◽  
Author(s):  
Celeste Sánchez-Noguera ◽  
Ines Stuhldreier ◽  
Jorge Cortés ◽  
Carlos Jiménez ◽  
Álvaro Morales ◽  
...  
Keyword(s):  
Costa Rica ◽  
Ocean Acidification ◽  
Cold Water ◽  
Coral Growth ◽  
Published Data ◽  
High Temporal Resolution ◽  
Carbonate System ◽  
Saturation State ◽  
Aragonite Saturation

Abstract. Numerous experiments have shown that ocean acidification impedes coral calcification, but knowledge about in situ reef ecosystem response to ocean acidification is still scarce. Bahía Culebra, situated at the northern Pacific coast of Costa Rica, is a location naturally exposed to acidic conditions due to the Papagayo seasonal upwelling. We measured pH and pCO2 in situ during two non-upwelling seasons (June 2012, May–June 2013), with a high temporal resolution of every 15 and 30 min, respectively, using two Submersible Autonomous Moored Instruments (SAMI-pH, SAMI-CO2). These results were compared with published data from the upwelling season 2009. Findings revealed that the carbonate system in Bahía Culebra shows a high temporal variability. Incoming offshore waters drive inter- and intra-seasonal changes. Lowest pH (7.8) and highest pCO2 (658.3 µatm) values measured during a cold-water intrusion event in the non-upwelling season were similar to those minimum values reported from upwelling season (pH = 7.8, pCO2 = 643.5 µatm), unveiling that natural acidification occurs sporadically also in non-upwelling season. This affects the interaction of photosynthesis, respiration, calcification, and carbonate dissolution and the resulting diel cycle of pH and pCO2 in the reefs of Bahía Culebra. During non-upwelling season, the aragonite saturation state (Ωa) rises to values of > 3.3 and enhances calcification. Aragonite saturation state values during upwelling season falls below 2.5, hampering calcification and coral growth. Low reef accretion in Bahía Culebra indicates high erosion rates and that these reefs grow on the verge of their ecological tolerance. The Ωa threshold values for coral growth, derived from the correlation between Ωa and coral linear extension rates, suggest that future ocean acidification will threaten reefs in Bahía Culebra. These data contribute to build a better understanding of the carbonate system dynamics and coral reefs key response (e.g. coral growth) to natural low-pH conditions, in upwelling areas in the Eastern Tropical Pacific and beyond.

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 CO<sub>2</sub> perturbation experiments: similarities and differences between dissolved inorganic carbon and total alkalinity manipulations

2009 ◽  
Vol 6 (10) ◽  
pp. 2145-2153 ◽  
Author(s):  
K. G. Schulz ◽  
J. Barcelos e Ramos ◽  
R. E. Zeebe ◽  
U. Riebesell
Keyword(s):  
Ocean Acidification ◽  
Inorganic Carbon ◽  
Dissolved Inorganic Carbon ◽  
Total Alkalinity ◽  
Calcium Carbonate Precipitation ◽  
Carbonate Chemistry ◽  
Carbonate System ◽  
Experimental Conditions ◽  
Saturation State ◽  
Basic Approaches

Abstract. Increasing atmospheric carbon dioxide (CO2) through human activities and invasion of anthropogenic CO2 into the surface ocean alters the seawater carbonate chemistry, increasing CO2 and bicarbonate (HCO3−) at the expense of carbonate ion (CO32−) concentrations. This redistribution in the dissolved inorganic carbon (DIC) pool decreases pH and carbonate saturation state (Ω). Several components of the carbonate system are considered potential key variables influencing for instance calcium carbonate precipitation in marine calcifiers such as coccolithophores, foraminifera, corals, mollusks and echinoderms. Unravelling the sensitivities of marine organisms and ecosystems to CO2 induced ocean acidification (OA) requires well-controlled experimental setups and accurate carbonate system manipulations. Here we describe and analyse the chemical changes involved in the two basic approaches for carbonate chemistry manipulation, i.e. changing DIC at constant total alkalinity (TA) and changing TA at constant DIC. Furthermore, we briefly introduce several methods to experimentally manipulate DIC and TA. Finally, we examine responses obtained with both approaches using published results for the coccolithophore Emiliania huxleyi. We conclude that under most experimental conditions in the context of ocean acidification DIC and TA manipulations yield similar changes in all parameters of the carbonate system, which implies direct comparability of data obtained with the two basic approaches for CO2 perturbation.

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 Natural ocean acidification at Papagayo upwelling system (north Pacific Costa Rica): implications for reef development

2018 ◽  
Vol 15 (8) ◽  
pp. 2349-2360 ◽  
Author(s):  
Celeste Sánchez-Noguera ◽  
Ines Stuhldreier ◽  
Jorge Cortés ◽  
Carlos Jiménez ◽  
Álvaro Morales ◽  
...  
Keyword(s):  
Costa Rica ◽  
Ocean Acidification ◽  
Cold Water ◽  
Coral Growth ◽  
Published Data ◽  
High Temporal Resolution ◽  
Carbonate System ◽  
Saturation State ◽  
Northern Pacific

Abstract. Numerous experiments have shown that ocean acidification impedes coral calcification, but knowledge about in situ reef ecosystem response to ocean acidification is still scarce. Bahía Culebra, situated at the northern Pacific coast of Costa Rica, is a location naturally exposed to acidic conditions due to the Papagayo seasonal upwelling. We measured pH and pCO2 in situ during two non-upwelling seasons (June 2012, May–June 2013), with a high temporal resolution of every 15 and 30 min, respectively, using two Submersible Autonomous Moored Instruments (SAMI-pH, SAMI-CO2). These results were compared with published data from the 2009 upwelling season. Findings revealed that the carbonate system in Bahía Culebra shows a high temporal variability. Incoming offshore waters drive intra- and interseasonal changes. Lowest pH (7.8) and highest pCO2 (658.3 µatm) values measured during a cold-water intrusion event in the non-upwelling season were similar to those minimum values reported from upwelling season (pH  =  7.8, pCO2  =  643.5 µatm), unveiling that natural acidification also occurs sporadically in the non-upwelling season. This affects the interaction of photosynthesis, respiration, calcification and carbonate dissolution and the resulting diel cycle of pH and pCO2 in the reefs of Bahía Culebra. During the non-upwelling season, the aragonite saturation state (Ωa) rises to values of  >  3.3 and during the upwelling season falls below 2.5. The Ωa threshold values for coral growth were derived from the correlation between measured Ωa and coral linear extension rates which were obtained from the literature and suggest that future ocean acidification will threaten the continued growth of reefs in Bahía Culebra. These data contribute to building a better understanding of the carbonate system dynamics and coral reefs' key response (e.g., coral growth) to natural low-pH conditions, in upwelling areas in the eastern tropical Pacific and beyond.

scholarly journals Effect of carbonate chemistry manipulations on calcification, respiration, and excretion of a Mediterranean pteropod

2012 ◽  
Vol 9 (5) ◽  
pp. 6169-6189 ◽  
Author(s):  
S. Comeau ◽  
J.-P. Gattuso ◽  
R. Jeffree ◽  
F. Gazeau
Keyword(s):  
Ocean Acidification ◽  
Total Alkalinity ◽  
Mediterranean Species ◽  
Carbonate Chemistry ◽  
Carbonate System ◽  
Saturation State ◽  
Polar Species ◽  
Mechanistic Understanding

Abstract. Although shelled pteropods are expected to be particularly sensitive to ocean acidification, the few available studies have mostly focused on polar species and have not allowed determining which parameter of the carbonate system controls their calcification. Specimens of the temperate Mediterranean species Creseis acicula were maintained under seven different conditions of the carbonate chemistry, obtained by manipulating pH and total alkalinity, with the goal to disentangle the effects of the pH and the saturation state with respect to aragonite (Ωa). Our results tend to show that respiration, excretion as well as rates of net and gross calcification were not directly affected by a decrease in pH but decreased significantly with a decrease in Ωa. Due to the difficulties in maintaining pteropods in the laboratory and the important variability in their abundances in our study site, long-term acclimation as well as replication of the experiment was not possible. However, we strongly believe that these results represent an important step in the mechanistic understanding of the effect of ocean acidification on pteropods physiology.

scholarly journals On CO<sub>2</sub> pertubation experiments: over-determination of carbonate chemistry reveals inconsistencies

2010 ◽  
Vol 7 (2) ◽  
pp. 1707-1726 ◽  
Author(s):  
C. J. M. Hoppe ◽  
G. Langer ◽  
S. D. Rokitta ◽  
D. A. Wolf-Gladrow ◽  
B. Rost
Keyword(s):  
Perturbation Methods ◽  
Input Parameter ◽  
Ion Concentration ◽  
Carbonate Chemistry ◽  
Carbonate System ◽  
Saturation State ◽  
Carbonate Ion ◽  
Input Parameters ◽  
Seawater Carbonate Chemistry

Abstract. Seawater carbonate chemistry is typically calculated from two measured parameters. Depending on the choice of these input parameters, discrepancies in calculated pCO2 have been recognized by marine chemists, but the significance of this phenomenon for CO2 perturbation experiments has so far not been determined. To mimic different pCO2 scenarios, two common perturbation methods for seawater carbonate chemistry (changing either DIC or TA) were applied using state-of-the-art protocols and equipment. The carbonate system was over-constrained by measuring DIC, TA, pH, and pCO2. Calculated pCO2 matched measured pCO2 if pH and TA or pH and DIC were chosen as input parameters, whereas pCO2 calculated from TA and DIC was considerably lower than measured values. This has important implications for CO2 perturbation experiments. First, calculated pCO2 values may not be comparable if different input parameters were used. Second, responses of organisms to acidification may be overestimated when using TA and DIC for calculations. This is especially troublesome for experiments with calcifiers, as carbonate ion concentration and thus calcite or aragonite saturation state are overestimated. We suggest refraining from measuring TA and DIC only and rather include pH as input parameter for carbonate chemistry calculations.

In situ observations of electromigration induced void behavior

1995 ◽  
Vol 53 ◽  
pp. 244-245
Author(s):  
T. Marieb ◽  
J. C. Bravman ◽  
P. Flinn ◽  
D. Gardner ◽  
M. Madden
Keyword(s):  
Electron Microscopy ◽  
Void Nucleation ◽  
Plan View ◽  
Transmission Electron ◽  
Nucleation Sites ◽  
Microelectronics Industry ◽  
In Situ Observations ◽  
Backscatter Electron Detector ◽  
Voltage Scanning

Electromigration and stress voiding have been active areas of research in the microelectronics industry for many years. While accelerated testing of these phenomena has been performed for the last 25 years[1-2], only recently has the introduction of high voltage scanning electron microscopy (HVSEM) made possible in situ testing of realistic, passivated, full thickness samples at high resolution.With a combination of in situ HVSEM and post-testing transmission electron microscopy (TEM) , electromigration void nucleation sites in both normal polycrystalline and near-bamboo pure Al were investigated. The effect of the microstructure of the lines on the void motion was also studied.The HVSEM used was a slightly modified JEOL 1200 EX II scanning TEM with a backscatter electron detector placed above the sample[3]. To observe electromigration in situ the sample was heated and the line had current supplied to it to accelerate the voiding process. After testing lines were prepared for TEM by employing the plan-view wedge technique [6].

scholarly journals In situ observations of coral spawning and spawn slick at Lankayan Island, Sabah, Malaysia

2021 ◽  
Vol 51 (1) ◽  
Author(s):  
Sze Hoon Gan ◽  
Zarinah Waheed ◽  
Fung Chen Chung ◽  
Davies Austin Spiji ◽  
Leony Sikim ◽  
...  
Keyword(s):  
Coral Spawning ◽  
In Situ Observations
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