The Experts below are selected from a list of 1575 Experts worldwide ranked by ideXlab platform
Gisela Lannig - One of the best experts on this subject based on the ideXlab platform.
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escape performance of temperate king scallop pecten maximus under ocean warming and acidification
Marine Biology, 2014Co-Authors: Burgel Schalkhausser, Christian Bock, Hans-otto Pörtner, Gisela LannigAbstract:Among bivalves, scallops are exceptional due to their capacity to escape from predators by swim- ming which is provided by rapid and strong claps that are produced by the phasic muscle interspersed with tonic muscle contractions. Based on the concept of oxy- gen and capacity-limited thermal tolerance, the following hypothesis was tested: ocean warming and acidification (OWA) would induce disturbances in aerobic metabolic scope and extracellular acid-case status and impair swim- ming performance in temperate scallops. Following long- term incubation under near-future OWA scenarios (20 vs. 10 °C (control) and 0.112 kPa CO2 (hypercapnia) vs. 0.040 kPa CO 2 (normocapnic control)), the clapping per- formance and metabolic rates (MR) were measured in resting (RMR) and fatigued (maximum MR) king scal- lops, Pecten maximus, from Roscoff, France. Exposure to OA, either alone or combined with warming, left MR and swimming parameters such as the total number of claps and clapping forces virtually unchanged. Only the dura- tion of the escape response was affected by OA which caused earlier exhaustion in hyper- than in normocapnic scallops at 10 °C. While maximum MR was unaffected, warm exposure increased RMR in both normocapnic and hypercapnic P. maximus resulting in similar Q10 values of ~2.2. The increased costs of maintenance and the observa- tion of strongly reduced haemolymph PO2 levels indicate that at 20 °C scallops have reached the upper thermal pejus
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Impact of ocean acidification on escape performance of the king scallop, Pecten maximus, from Norway
Marine Biology, 2012Co-Authors: Burgel Schalkhausser, Kristina Stemmer, Christian Bock, Hans-otto Pörtner, Thomas Brey, Gisela LannigAbstract:The ongoing process of ocean acidification already affects marine life, and according to the concept of oxygen and capacity limitation of thermal tolerance, these effects may be intensified at the borders of the thermal tolerance window. We studied the effects of elevated CO2 concentrations on clapping performance and energy metabolism of the commercially important scallop Pecten maximus. Individuals were exposed for at least 30 days to 4 °C (winter) or to 10 °C (spring/summer) at either ambient (0.04 kPa, Normocapnia) or predicted future PCO2 levels (0.11 kPa, hypercapnia). Cold-exposed (4 °C) groups revealed thermal stress exacerbated by PCO2 indicated by a high mortality overall and its increase from 55 % under Normocapnia to 90 % under hypercapnia. We therefore excluded the 4 °C groups from further experimentation. Scallops at 10 °C showed impaired clapping performance following hypercapnic exposure. Force production was significantly reduced although the number of claps was unchanged between Normocapnia- and hypercapnia-exposed scallops. The difference between maximal and resting metabolic rate (aerobic scope) of the hypercapnic scallops was significantly reduced compared with normocapnic animals, indicating a reduction in net aerobic scope. Our data confirm that ocean acidification narrows the thermal tolerance range of scallops resulting in elevated vulnerability to temperature extremes and impairs the animal’s performance capacity with potentially detrimental consequences for its fitness and survival in the ocean of tomorrow.
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interactive effects of salinity and elevated co2 levels on juvenile eastern oysters crassostrea virginica
The Journal of Experimental Biology, 2012Co-Authors: Gary H Dickinson, Gisela Lannig, Christian Bock, Anna V Ivanina, Omera B Matoo, Hans O Portner, Elia Beniash, Inna M SokolovaAbstract:SUMMARY Rising levels of atmospheric CO 2 lead to acidification of the ocean and alter seawater carbonate chemistry, which can negatively impact calcifying organisms, including mollusks. In estuaries, exposure to elevated CO 2 levels often co-occurs with other stressors, such as reduced salinity, which enhances the acidification trend, affects ion and acid–base regulation of estuarine calcifiers and modifies their response to ocean acidification. We studied the interactive effects of salinity and partial pressure of CO 2 ( P CO2 ) on biomineralization and energy homeostasis in juveniles of the eastern oyster, Crassostrea virginica , a common estuarine bivalve. Juveniles were exposed for 11 weeks to one of two environmentally relevant salinities (30 or 15 PSU) either at current atmospheric P CO2 (∼400 μatm, Normocapnia) or P CO2 projected by moderate IPCC scenarios for the year 2100 (∼700–800 μatm, hypercapnia). Exposure of the juvenile oysters to elevated P CO2 and/or low salinity led to a significant increase in mortality, reduction of tissue energy stores (glycogen and lipid) and negative soft tissue growth, indicating energy deficiency. Interestingly, tissue ATP levels were not affected by exposure to changing salinity and P CO2 , suggesting that juvenile oysters maintain their cellular energy status at the expense of lipid and glycogen stores. At the same time, no compensatory upregulation of carbonic anhydrase activity was found under the conditions of low salinity and high P CO2 . Metabolic profiling using magnetic resonance spectroscopy revealed altered metabolite status following low salinity exposure; specifically, acetate levels were lower in hypercapnic than in normocapnic individuals at low salinity. Combined exposure to hypercapnia and low salinity negatively affected mechanical properties of shells of the juveniles, resulting in reduced hardness and fracture resistance. Thus, our data suggest that the combined effects of elevated P CO2 and fluctuating salinity may jeopardize the survival of eastern oysters because of weakening of their shells and increased energy consumption.
Chungming Chu - One of the best experts on this subject based on the ideXlab platform.
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differences in baseline factors and survival between Normocapnia compensated respiratory acidosis and decompensated respiratory acidosis in copd exacerbation a pilot study
Respirology, 2016Co-Authors: Chungtat Lun, Miranda Sn Tsui, Suetlai Cheng, Veronica L Chan, Wahshing Leung, Alice P S Cheung, Chungming ChuAbstract:Background and objective Patients with chronic obstructive pulmonary disease (COPD) experiencing acute exacerbation (AE-COPD) with decompensated respiratory acidosis are known to have poor outcomes in terms of recurrent respiratory failure and death. However, the outcomes of AE-COPD patients with compensated respiratory acidosis are not known. Methods We performed a 1-year prospective, single-centre, cohort study in patients surviving the index admission for AE-COPD to compare baseline factors between groups with Normocapnia, compensated respiratory acidosis and decompensated respiratory acidosis. Survival analysis was done to examine time to readmissions, life-threatening events and death. Results A total of 250 patients fulfilling the inclusion and exclusion criteria were recruited and 245 patients were analysed. Compared with Normocapnia, both compensated and decompensated respiratory acidosis are associated with lower FEV1 % (P < 0.001), higher GOLD stage (P = 0.003, <0.001) and higher BODE index (P = 0.038, 0.001) and a shorter time to life-threatening events (P < 0.001). Comparing compensated and decompensated respiratory acidosis, there was no difference in FEV1 (% predicted) (P = 0.15), GOLD stage (P = 0.091), BODE index (P = 0.158) or time to life-threatening events (P = 0.301). High PaCO2 level (P = 0.002) and previous use of non-invasive ventilation (NIV) in acute setting (P < 0.001) are predictive factors of future life-threatening events by multivariate analysis. Conclusions Compared with Normocapnia, both compensated and decompensated respiratory acidosis are associated with poorer lung function and higher risk of future life-threatening events. High PaCO2 level and past history of NIV use in acute settings were predictive factors for future life-threatening events. Compensated respiratory acidosis warrants special attention and optimization of medical therapy as it poses risk of life-threatening events.
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late breaking abstract baseline factors and survival difference between Normocapnia compensated respiratory acidosis and decompensated respiratory acidosis in copd exacerbation
European Respiratory Journal, 2014Co-Authors: Chungtat Lun, Miranda Sn Tsui, Suetlai Cheng, Pikshan Cheung, Veronica L Chan, Wahshing Leung, Chungming ChuAbstract:Background Patients experiencing acute exacerbation of chronic obstructive pulmonary disease (AE-COPD) with decompensated respiratory acidosis are known to have poor outcomes in terms of recurrent respiratory failure and death. The outcomes of AE-COPD patients with compensated respiratory acidosis are not known. Methods and Objective We performed a prospective, single-centre, cohort study in patients with AE-COPD for one year, to compare baseline factors between groups with Normocapnia, compensated respiratory acidosis and decompensated respiratory acidosis. Survival analysis was done to examine time to readmissions, life-threatening events and death. Results Compared with Normocapnia, both compensated and decompensated respiratory acidosis are associated with lower FEV1 % , higher GOLD stage and higher BODE index and they have shorter time to life-threatening events (fig1). Comparing compensated and decompensated respiratory acidosis, there was no difference in FEV1 (% predicted), GOLD stage, BODE index, and time to life-threatening events. PaCO2 and previous use of non-invasive ventilation (NIV) in acute setting are predictive factors of future life-threatening events by multivariate analysis. Conclusions Comparing with Normocapnia, both compensated and decompensated respiratory are associated with poorer lung function and at high risk of future life-threatening events. PaCO2 and past history of NIV use in acute settings were predictive factors for future life-threatening events. Compensated respiratory acidosis warrants special attention and optimisation of medical therapy as it poses risk of life-threatening events.
Chungtat Lun - One of the best experts on this subject based on the ideXlab platform.
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differences in baseline factors and survival between Normocapnia compensated respiratory acidosis and decompensated respiratory acidosis in copd exacerbation a pilot study
Respirology, 2016Co-Authors: Chungtat Lun, Miranda Sn Tsui, Suetlai Cheng, Veronica L Chan, Wahshing Leung, Alice P S Cheung, Chungming ChuAbstract:Background and objective Patients with chronic obstructive pulmonary disease (COPD) experiencing acute exacerbation (AE-COPD) with decompensated respiratory acidosis are known to have poor outcomes in terms of recurrent respiratory failure and death. However, the outcomes of AE-COPD patients with compensated respiratory acidosis are not known. Methods We performed a 1-year prospective, single-centre, cohort study in patients surviving the index admission for AE-COPD to compare baseline factors between groups with Normocapnia, compensated respiratory acidosis and decompensated respiratory acidosis. Survival analysis was done to examine time to readmissions, life-threatening events and death. Results A total of 250 patients fulfilling the inclusion and exclusion criteria were recruited and 245 patients were analysed. Compared with Normocapnia, both compensated and decompensated respiratory acidosis are associated with lower FEV1 % (P < 0.001), higher GOLD stage (P = 0.003, <0.001) and higher BODE index (P = 0.038, 0.001) and a shorter time to life-threatening events (P < 0.001). Comparing compensated and decompensated respiratory acidosis, there was no difference in FEV1 (% predicted) (P = 0.15), GOLD stage (P = 0.091), BODE index (P = 0.158) or time to life-threatening events (P = 0.301). High PaCO2 level (P = 0.002) and previous use of non-invasive ventilation (NIV) in acute setting (P < 0.001) are predictive factors of future life-threatening events by multivariate analysis. Conclusions Compared with Normocapnia, both compensated and decompensated respiratory acidosis are associated with poorer lung function and higher risk of future life-threatening events. High PaCO2 level and past history of NIV use in acute settings were predictive factors for future life-threatening events. Compensated respiratory acidosis warrants special attention and optimization of medical therapy as it poses risk of life-threatening events.
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late breaking abstract baseline factors and survival difference between Normocapnia compensated respiratory acidosis and decompensated respiratory acidosis in copd exacerbation
European Respiratory Journal, 2014Co-Authors: Chungtat Lun, Miranda Sn Tsui, Suetlai Cheng, Pikshan Cheung, Veronica L Chan, Wahshing Leung, Chungming ChuAbstract:Background Patients experiencing acute exacerbation of chronic obstructive pulmonary disease (AE-COPD) with decompensated respiratory acidosis are known to have poor outcomes in terms of recurrent respiratory failure and death. The outcomes of AE-COPD patients with compensated respiratory acidosis are not known. Methods and Objective We performed a prospective, single-centre, cohort study in patients with AE-COPD for one year, to compare baseline factors between groups with Normocapnia, compensated respiratory acidosis and decompensated respiratory acidosis. Survival analysis was done to examine time to readmissions, life-threatening events and death. Results Compared with Normocapnia, both compensated and decompensated respiratory acidosis are associated with lower FEV1 % , higher GOLD stage and higher BODE index and they have shorter time to life-threatening events (fig1). Comparing compensated and decompensated respiratory acidosis, there was no difference in FEV1 (% predicted), GOLD stage, BODE index, and time to life-threatening events. PaCO2 and previous use of non-invasive ventilation (NIV) in acute setting are predictive factors of future life-threatening events by multivariate analysis. Conclusions Comparing with Normocapnia, both compensated and decompensated respiratory are associated with poorer lung function and at high risk of future life-threatening events. PaCO2 and past history of NIV use in acute settings were predictive factors for future life-threatening events. Compensated respiratory acidosis warrants special attention and optimisation of medical therapy as it poses risk of life-threatening events.
Burgel Schalkhausser - One of the best experts on this subject based on the ideXlab platform.
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escape performance of temperate king scallop pecten maximus under ocean warming and acidification
Marine Biology, 2014Co-Authors: Burgel Schalkhausser, Christian Bock, Hans-otto Pörtner, Gisela LannigAbstract:Among bivalves, scallops are exceptional due to their capacity to escape from predators by swim- ming which is provided by rapid and strong claps that are produced by the phasic muscle interspersed with tonic muscle contractions. Based on the concept of oxy- gen and capacity-limited thermal tolerance, the following hypothesis was tested: ocean warming and acidification (OWA) would induce disturbances in aerobic metabolic scope and extracellular acid-case status and impair swim- ming performance in temperate scallops. Following long- term incubation under near-future OWA scenarios (20 vs. 10 °C (control) and 0.112 kPa CO2 (hypercapnia) vs. 0.040 kPa CO 2 (normocapnic control)), the clapping per- formance and metabolic rates (MR) were measured in resting (RMR) and fatigued (maximum MR) king scal- lops, Pecten maximus, from Roscoff, France. Exposure to OA, either alone or combined with warming, left MR and swimming parameters such as the total number of claps and clapping forces virtually unchanged. Only the dura- tion of the escape response was affected by OA which caused earlier exhaustion in hyper- than in normocapnic scallops at 10 °C. While maximum MR was unaffected, warm exposure increased RMR in both normocapnic and hypercapnic P. maximus resulting in similar Q10 values of ~2.2. The increased costs of maintenance and the observa- tion of strongly reduced haemolymph PO2 levels indicate that at 20 °C scallops have reached the upper thermal pejus
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Impact of ocean acidification on escape performance of the king scallop, Pecten maximus, from Norway
Marine Biology, 2012Co-Authors: Burgel Schalkhausser, Kristina Stemmer, Christian Bock, Hans-otto Pörtner, Thomas Brey, Gisela LannigAbstract:The ongoing process of ocean acidification already affects marine life, and according to the concept of oxygen and capacity limitation of thermal tolerance, these effects may be intensified at the borders of the thermal tolerance window. We studied the effects of elevated CO2 concentrations on clapping performance and energy metabolism of the commercially important scallop Pecten maximus. Individuals were exposed for at least 30 days to 4 °C (winter) or to 10 °C (spring/summer) at either ambient (0.04 kPa, Normocapnia) or predicted future PCO2 levels (0.11 kPa, hypercapnia). Cold-exposed (4 °C) groups revealed thermal stress exacerbated by PCO2 indicated by a high mortality overall and its increase from 55 % under Normocapnia to 90 % under hypercapnia. We therefore excluded the 4 °C groups from further experimentation. Scallops at 10 °C showed impaired clapping performance following hypercapnic exposure. Force production was significantly reduced although the number of claps was unchanged between Normocapnia- and hypercapnia-exposed scallops. The difference between maximal and resting metabolic rate (aerobic scope) of the hypercapnic scallops was significantly reduced compared with normocapnic animals, indicating a reduction in net aerobic scope. Our data confirm that ocean acidification narrows the thermal tolerance range of scallops resulting in elevated vulnerability to temperature extremes and impairs the animal’s performance capacity with potentially detrimental consequences for its fitness and survival in the ocean of tomorrow.
Christian Bock - One of the best experts on this subject based on the ideXlab platform.
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escape performance of temperate king scallop pecten maximus under ocean warming and acidification
Marine Biology, 2014Co-Authors: Burgel Schalkhausser, Christian Bock, Hans-otto Pörtner, Gisela LannigAbstract:Among bivalves, scallops are exceptional due to their capacity to escape from predators by swim- ming which is provided by rapid and strong claps that are produced by the phasic muscle interspersed with tonic muscle contractions. Based on the concept of oxy- gen and capacity-limited thermal tolerance, the following hypothesis was tested: ocean warming and acidification (OWA) would induce disturbances in aerobic metabolic scope and extracellular acid-case status and impair swim- ming performance in temperate scallops. Following long- term incubation under near-future OWA scenarios (20 vs. 10 °C (control) and 0.112 kPa CO2 (hypercapnia) vs. 0.040 kPa CO 2 (normocapnic control)), the clapping per- formance and metabolic rates (MR) were measured in resting (RMR) and fatigued (maximum MR) king scal- lops, Pecten maximus, from Roscoff, France. Exposure to OA, either alone or combined with warming, left MR and swimming parameters such as the total number of claps and clapping forces virtually unchanged. Only the dura- tion of the escape response was affected by OA which caused earlier exhaustion in hyper- than in normocapnic scallops at 10 °C. While maximum MR was unaffected, warm exposure increased RMR in both normocapnic and hypercapnic P. maximus resulting in similar Q10 values of ~2.2. The increased costs of maintenance and the observa- tion of strongly reduced haemolymph PO2 levels indicate that at 20 °C scallops have reached the upper thermal pejus
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Impact of ocean acidification on escape performance of the king scallop, Pecten maximus, from Norway
Marine Biology, 2012Co-Authors: Burgel Schalkhausser, Kristina Stemmer, Christian Bock, Hans-otto Pörtner, Thomas Brey, Gisela LannigAbstract:The ongoing process of ocean acidification already affects marine life, and according to the concept of oxygen and capacity limitation of thermal tolerance, these effects may be intensified at the borders of the thermal tolerance window. We studied the effects of elevated CO2 concentrations on clapping performance and energy metabolism of the commercially important scallop Pecten maximus. Individuals were exposed for at least 30 days to 4 °C (winter) or to 10 °C (spring/summer) at either ambient (0.04 kPa, Normocapnia) or predicted future PCO2 levels (0.11 kPa, hypercapnia). Cold-exposed (4 °C) groups revealed thermal stress exacerbated by PCO2 indicated by a high mortality overall and its increase from 55 % under Normocapnia to 90 % under hypercapnia. We therefore excluded the 4 °C groups from further experimentation. Scallops at 10 °C showed impaired clapping performance following hypercapnic exposure. Force production was significantly reduced although the number of claps was unchanged between Normocapnia- and hypercapnia-exposed scallops. The difference between maximal and resting metabolic rate (aerobic scope) of the hypercapnic scallops was significantly reduced compared with normocapnic animals, indicating a reduction in net aerobic scope. Our data confirm that ocean acidification narrows the thermal tolerance range of scallops resulting in elevated vulnerability to temperature extremes and impairs the animal’s performance capacity with potentially detrimental consequences for its fitness and survival in the ocean of tomorrow.
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interactive effects of salinity and elevated co2 levels on juvenile eastern oysters crassostrea virginica
The Journal of Experimental Biology, 2012Co-Authors: Gary H Dickinson, Gisela Lannig, Christian Bock, Anna V Ivanina, Omera B Matoo, Hans O Portner, Elia Beniash, Inna M SokolovaAbstract:SUMMARY Rising levels of atmospheric CO 2 lead to acidification of the ocean and alter seawater carbonate chemistry, which can negatively impact calcifying organisms, including mollusks. In estuaries, exposure to elevated CO 2 levels often co-occurs with other stressors, such as reduced salinity, which enhances the acidification trend, affects ion and acid–base regulation of estuarine calcifiers and modifies their response to ocean acidification. We studied the interactive effects of salinity and partial pressure of CO 2 ( P CO2 ) on biomineralization and energy homeostasis in juveniles of the eastern oyster, Crassostrea virginica , a common estuarine bivalve. Juveniles were exposed for 11 weeks to one of two environmentally relevant salinities (30 or 15 PSU) either at current atmospheric P CO2 (∼400 μatm, Normocapnia) or P CO2 projected by moderate IPCC scenarios for the year 2100 (∼700–800 μatm, hypercapnia). Exposure of the juvenile oysters to elevated P CO2 and/or low salinity led to a significant increase in mortality, reduction of tissue energy stores (glycogen and lipid) and negative soft tissue growth, indicating energy deficiency. Interestingly, tissue ATP levels were not affected by exposure to changing salinity and P CO2 , suggesting that juvenile oysters maintain their cellular energy status at the expense of lipid and glycogen stores. At the same time, no compensatory upregulation of carbonic anhydrase activity was found under the conditions of low salinity and high P CO2 . Metabolic profiling using magnetic resonance spectroscopy revealed altered metabolite status following low salinity exposure; specifically, acetate levels were lower in hypercapnic than in normocapnic individuals at low salinity. Combined exposure to hypercapnia and low salinity negatively affected mechanical properties of shells of the juveniles, resulting in reduced hardness and fracture resistance. Thus, our data suggest that the combined effects of elevated P CO2 and fluctuating salinity may jeopardize the survival of eastern oysters because of weakening of their shells and increased energy consumption.