Ocean acidification is expected to have dramatic impacts on oceanic ecosystems, yet surprisingly ... more Ocean acidification is expected to have dramatic impacts on oceanic ecosystems, yet surprisingly few studies currently examine long-term adaptive and plastic responses of marine invertebrates to pCO 2 stress. Here, we exposed populations of the common copepod Pseudocalanus acuspes to three pCO 2 regimes (400, 900, and 1550 latm) for two generations, after which we conducted a reciprocal transplant experiment. A de novo transcriptome was assembled, annotated, and gene expression data revealed that genes involved in RNA transcription were strongly down-regulated in populations with long-term exposure to a high pCO 2 environment, even after transplantation back to control levels. In addition, 747 000 SNPs were identified, out of which 1513 showed consistent changes in nucleotide frequency between replicates of control and high pCO 2 populations. Functions involving RNA transcription and ribosomal function, as well as ion transport and oxidative phosphorylation, were highly overrepresented. We thus conclude that pCO 2 stress appears to impose selection in copepods on RNA synthesis and translation, possibly modulated by helicase expression. Using a physiological hypothesis-testing strategy to mine gene expression data, we herein increase the power to detect cellular targets of ocean acidification. This novel approach seems promising for future studies of effects of environmental changes in ecologically important nonmodel organisms.
This file provides the excel sheet for the calculations of normal distributions and their fits to... more This file provides the excel sheet for the calculations of normal distributions and their fits to particle counter outputs. Ready to use!
In the present study, six laboratory populations of the calanoid copepod Pseudocalanus acuspes we... more In the present study, six laboratory populations of the calanoid copepod Pseudocalanus acuspes were established at three different CO2 partial pressures (pCO2 of 400, 900 and 1550 µatm) and grown for two generations at these conditions. Our results show evidence of buffering of OA effects as a result of transgenerational transmission. Second generation adults showed a 29% decrease in fecundity at 900 µatm CO2 compared to 400 µatm CO2 accompanied by a 10% increase in metabolic rate indicative of metabolic stress. Reciprocal transplant tests demonstrated that this effect was reversible and the expression of phenotypic plasticity. Furthermore, these tests showed that at a pCO2 exceeding the natural range experienced by P. acuspes (1550 µatm), fecundity would have decreased by as much as 67% compared to at 400 µatm CO2 as a result of this plasticity. However, transgenerational buffering partly reduced OA effects so that the loss of fecundity remained at a level comparable to that at 900...
Våra utsläpp av koldioxid ökar i en oroväckande takt. Vi vet att en konsekvens är global uppvärmn... more Våra utsläpp av koldioxid ökar i en oroväckande takt. Vi vet att en konsekvens är global uppvärmning, men det som an-tagligen är mindre känt är vad marina kemister kallar " det andra koldioxidproblemet " . En tredjedel av den koldioxid som släpps ut absorberas av världens hav. I havet reagerar den med kalcium och vatten och bildar kolsyra. Detta gör att pH i oceanerna sjunker, och vi får en försurning. En två millimeter lång hona av hoppkräftan Pseudocalanus acuspes med ägg. Våra studier visar att både ämnesomsättningen och äggproduktionen minskade hos hopp-kräftor som utsattes för försurade miljöer. u nder de senaste trehundra miljoner åren har pH-värdet i havets ytvatten varit någor-lunda stabilt, med ett genom-snitt på cirka 8,2. Idag är det runt 8,1, en minskning som motsvarar en ökning i surhet med 25 procent under de senas-te två århundradena. oceanerna absorbe-rar för närvarande cirka 22 miljoner ton koldioxid per dag. Prognoser baserade på dessa siffror visar att i...
We measured ingestion rate (IR), egg production rate (EPR) and egg hatching success (EHS) at incr... more We measured ingestion rate (IR), egg production rate (EPR) and egg hatching success (EHS) at increasing prey concentrations and calculated egg production efficiency (EPE) and maintenance rate (MR) in the estuarine copepod Acartia tonsafed three different algal diets. EPR and EHS were relatively more affected by prey species than by prey concentration. EPEs were constant among carbon concentrations (C) on a diet of Rhodomonas baltica(0.202 ± 0.055, mean ± SD) and Dunaliella tertiolecta(0.034 ± 0.015), but decreased significantly from 0.371 ± 0.062 (mean of two lowest prey concentrations) to 0.200 ± 0.019 at the highest concentration of Thalassiosira weissflogii. In general it seems that other requirements than C demand limit EPE and EHS in A. tonsa. The MR (IR when EPR = 0) was significantly higher on D. tertiolecta, which also yielded the lowest EPEs, and it seems that variations in maintenance requirements may have been instrumental in evoking EPE variations as well.
Measurements of algal cell concentrations on particle counters have long been limited to monoalga... more Measurements of algal cell concentrations on particle counters have long been limited to monoalgal samples due to the difficulty of discrimination of cells with overlapping sizes. Here I suggest a simple method for enumeration of algal cells in mixes of monocultures of algae with overlapping size distributions using computer spreadsheets. The method is based on correlations of the sum of two or more normal or lognormal distributions to the outputs from a particle counter. The correlations exhibit only one local optimum and by iterating the procedure several times an optimal value for cell concentrations is reached. Tests showed that the optimal values are reached from a wide range of starting values of peak sizes, medians, and standard deviations of the fitted distributions. Often no more than 3 iterations are needed to reach the optimal values. The method was tested against direct particle counts of mixed algal samples. The values obtained by the fits were always better than those ...
Search: onr:"swepub:oai:services.scigloo.org:112460" > Effects of salinity... ... Th... more Search: onr:"swepub:oai:services.scigloo.org:112460" > Effects of salinity... ... Thor, Peter, 1965-(author) Göteborgs universitet, Institutionen för marin ekologi Calliari, Danilo, 1969-(author) Göteborgs universitet, Institutionen för marin ekologi Andersen Borg, M (author) ...
Ocean acidification is expected to have dramatic impacts on oceanic ecosystems, yet surprisingly ... more Ocean acidification is expected to have dramatic impacts on oceanic ecosystems, yet surprisingly few studies currently examine long-term adaptive and plastic responses of marine invertebrates to pCO 2 stress. Here, we exposed populations of the common copepod Pseudocalanus acuspes to three pCO 2 regimes (400, 900, and 1550 latm) for two generations, after which we conducted a reciprocal transplant experiment. A de novo transcriptome was assembled, annotated, and gene expression data revealed that genes involved in RNA transcription were strongly down-regulated in populations with long-term exposure to a high pCO 2 environment, even after transplantation back to control levels. In addition, 747 000 SNPs were identified, out of which 1513 showed consistent changes in nucleotide frequency between replicates of control and high pCO 2 populations. Functions involving RNA transcription and ribosomal function, as well as ion transport and oxidative phosphorylation, were highly overrepresented. We thus conclude that pCO 2 stress appears to impose selection in copepods on RNA synthesis and translation, possibly modulated by helicase expression. Using a physiological hypothesis-testing strategy to mine gene expression data, we herein increase the power to detect cellular targets of ocean acidification. This novel approach seems promising for future studies of effects of environmental changes in ecologically important nonmodel organisms.
This file provides the excel sheet for the calculations of normal distributions and their fits to... more This file provides the excel sheet for the calculations of normal distributions and their fits to particle counter outputs. Ready to use!
In the present study, six laboratory populations of the calanoid copepod Pseudocalanus acuspes we... more In the present study, six laboratory populations of the calanoid copepod Pseudocalanus acuspes were established at three different CO2 partial pressures (pCO2 of 400, 900 and 1550 µatm) and grown for two generations at these conditions. Our results show evidence of buffering of OA effects as a result of transgenerational transmission. Second generation adults showed a 29% decrease in fecundity at 900 µatm CO2 compared to 400 µatm CO2 accompanied by a 10% increase in metabolic rate indicative of metabolic stress. Reciprocal transplant tests demonstrated that this effect was reversible and the expression of phenotypic plasticity. Furthermore, these tests showed that at a pCO2 exceeding the natural range experienced by P. acuspes (1550 µatm), fecundity would have decreased by as much as 67% compared to at 400 µatm CO2 as a result of this plasticity. However, transgenerational buffering partly reduced OA effects so that the loss of fecundity remained at a level comparable to that at 900...
Våra utsläpp av koldioxid ökar i en oroväckande takt. Vi vet att en konsekvens är global uppvärmn... more Våra utsläpp av koldioxid ökar i en oroväckande takt. Vi vet att en konsekvens är global uppvärmning, men det som an-tagligen är mindre känt är vad marina kemister kallar " det andra koldioxidproblemet " . En tredjedel av den koldioxid som släpps ut absorberas av världens hav. I havet reagerar den med kalcium och vatten och bildar kolsyra. Detta gör att pH i oceanerna sjunker, och vi får en försurning. En två millimeter lång hona av hoppkräftan Pseudocalanus acuspes med ägg. Våra studier visar att både ämnesomsättningen och äggproduktionen minskade hos hopp-kräftor som utsattes för försurade miljöer. u nder de senaste trehundra miljoner åren har pH-värdet i havets ytvatten varit någor-lunda stabilt, med ett genom-snitt på cirka 8,2. Idag är det runt 8,1, en minskning som motsvarar en ökning i surhet med 25 procent under de senas-te två århundradena. oceanerna absorbe-rar för närvarande cirka 22 miljoner ton koldioxid per dag. Prognoser baserade på dessa siffror visar att i...
We measured ingestion rate (IR), egg production rate (EPR) and egg hatching success (EHS) at incr... more We measured ingestion rate (IR), egg production rate (EPR) and egg hatching success (EHS) at increasing prey concentrations and calculated egg production efficiency (EPE) and maintenance rate (MR) in the estuarine copepod Acartia tonsafed three different algal diets. EPR and EHS were relatively more affected by prey species than by prey concentration. EPEs were constant among carbon concentrations (C) on a diet of Rhodomonas baltica(0.202 ± 0.055, mean ± SD) and Dunaliella tertiolecta(0.034 ± 0.015), but decreased significantly from 0.371 ± 0.062 (mean of two lowest prey concentrations) to 0.200 ± 0.019 at the highest concentration of Thalassiosira weissflogii. In general it seems that other requirements than C demand limit EPE and EHS in A. tonsa. The MR (IR when EPR = 0) was significantly higher on D. tertiolecta, which also yielded the lowest EPEs, and it seems that variations in maintenance requirements may have been instrumental in evoking EPE variations as well.
Measurements of algal cell concentrations on particle counters have long been limited to monoalga... more Measurements of algal cell concentrations on particle counters have long been limited to monoalgal samples due to the difficulty of discrimination of cells with overlapping sizes. Here I suggest a simple method for enumeration of algal cells in mixes of monocultures of algae with overlapping size distributions using computer spreadsheets. The method is based on correlations of the sum of two or more normal or lognormal distributions to the outputs from a particle counter. The correlations exhibit only one local optimum and by iterating the procedure several times an optimal value for cell concentrations is reached. Tests showed that the optimal values are reached from a wide range of starting values of peak sizes, medians, and standard deviations of the fitted distributions. Often no more than 3 iterations are needed to reach the optimal values. The method was tested against direct particle counts of mixed algal samples. The values obtained by the fits were always better than those ...
Search: onr:"swepub:oai:services.scigloo.org:112460" > Effects of salinity... ... Th... more Search: onr:"swepub:oai:services.scigloo.org:112460" > Effects of salinity... ... Thor, Peter, 1965-(author) Göteborgs universitet, Institutionen för marin ekologi Calliari, Danilo, 1969-(author) Göteborgs universitet, Institutionen för marin ekologi Andersen Borg, M (author) ...
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