scholarly journals Repeat exposure to hypercapnic seawater modifies growth and oxidative status in a tolerant burrowing clam

2021 ◽  
Author(s):  
Samuel J. Gurr ◽  
Shelly A. Trigg ◽  
Brent Vadopalas ◽  
Steven B. Roberts ◽  
Hollie M. Putnam
Keyword(s):  
Stress Intensity ◽  
Marine Invertebrates ◽  
Life Stage ◽  
Life Time ◽  
Oxidative Status ◽  
Elevated Pco2 ◽  
Ambient Conditions ◽  
Shell Size ◽  
Beneficial Effects ◽  
Repeat Exposure

Whereas low levels of thermal stress, irradiance, and dietary restriction can have beneficial effects for many taxa, stress acclimation remains understudied in marine invertebrates, despite being threatened by climate change stressors such as ocean acidification. To test for life-stage and stress-intensity dependence in eliciting enhanced tolerance under subsequent stress encounters, we initially conditioned pediveliger Pacific geoduck (Panopea generosa) larvae to (i) ambient and moderately elevated pCO2 (920 µatm and 2800 µatm, respectively) for 110 days, (ii) secondarily applied a 7-day exposure to ambient, moderate, and severely elevated pCO2 (750 µatm, 2800 µatm, and 4900 µatm, respectively), followed by 7 days in ambient conditions, and (iii) implemented a 7-day third exposure to ambient (970 µatm) and moderate pCO2 (3000 µatm). Initial conditioning to moderate pCO2 stress followed by second and third exposure to severe and moderate pCO2 stress increased respiration rate, organic biomass, and shell size suggesting a stress-intensity-dependent effect on energetics. Additionally, stress-acclimated clams had lower antioxidant capacity compared to clams under ambient conditions, supporting the hypothesis that stress over postlarval-to-juvenile development affects oxidative status later in life. Time series and stress intensity-specific approaches can reveal life-stages and magnitudes of exposure, respectively, that may elicit beneficial phenotypic variation.

scholarly journals Repeat Exposure to Hypercapnic Seawater Modifies Performance and Oxidative Status in a Tolerant Burrowing Clam

2020 ◽  
Author(s):  
Samuel J. Gurr ◽  
Shelly A. Trigg ◽  
Brent Vadopalas ◽  
Steven B. Roberts ◽  
Hollie M. Putnam
Keyword(s):  
Stress Intensity ◽  
Marine Invertebrates ◽  
Life Stage ◽  
Oxidative Status ◽  
Ambient Conditions ◽  
Shell Size ◽  
Stress Acclimation ◽  
Show Evidence ◽  
Repeat Exposure ◽  
Summary Statement

AbstractModerate oxidative stress is a hypothesized driver of enhanced stress tolerance and lifespan. Whereas thermal stress, irradiance, and dietary restriction show evidence of dose-dependent benefits for many taxa, stress acclimation remains understudied in marine invertebrates, despite being threatened by climate change stressors such as ocean acidification. To test for life-stage and stress-intensity dependence in eliciting enhanced tolerance under subsequent stress encounters, we initially conditioned pediveliger Pacific geoduck (Panopea generosa) larvae to (i) ambient and moderately elevated pCO2 (920 μatm and 2800 μatm, respectively) for 110 days, (ii) secondarily applied a 7-day exposure to ambient, moderate, and severely elevated pCO2 (750 μatm, 2800 μatm, and 4900 μatm, respectively), followed by 7 days in ambient conditions, and (iii) implemented a modified-reciprocal 7-day tertiary exposure to ambient (970 μatm) and moderate pCO2 (3000 μatm). Initial conditioning to moderate pCO2 stress followed by secondary and tertiary exposure to severe and moderate pCO2 stress increased respiration rate, organic biomass, and shell size suggesting a stress-intensity-dependent effect on energetics. Additionally, stress-acclimated clams had lower antioxidant capacity compared to clams under initial ambient conditions, supporting the hypothesis that stress over postlarval-to-juvenile development affects oxidative status later in life. We posit two subcellular mechanisms underpinning stress-intensity-dependent effects on mitochondrial pathways and energy partitioning: i) stress-induced attenuation of mitochondrial function and ii) adaptive mitochondrial shift under moderate stress. Time series and stress intensity-specific approaches can reveal life-stages and magnitudes of exposure, respectively, that may elicit beneficial phenotypic variation.Summary statementHypercapnic conditions during postlarval development improves physiological performance and oxidative status. This novel investigation of adaptive stress acclimation highlights the plasticity of bioenergetic and subcellular responses in Panopea generosa.

scholarly journals Tolerant Larvae and Sensitive Juveniles: Integrating Metabolomics and Whole-Organism Responses to Define Life-Stage Specific Sensitivity to Ocean Acidification in the American Lobster

Metabolites ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 584
Author(s):  
Fanny Noisette ◽  
Piero Calosi ◽  
Diana Madeira ◽  
Mathilde Chemel ◽  
Kayla Menu-Courey ◽  
...  
Keyword(s):  
Ocean Acidification ◽  
Environmental Changes ◽  
Marine Invertebrates ◽  
Marine Invertebrate ◽  
Life Stage ◽  
Homarus Americanus ◽  
Life Cycles ◽  
Elevated Pco2 ◽  
High Pco2 ◽  
American Lobster

Bentho-pelagic life cycles are the dominant reproductive strategy in marine invertebrates, providing great dispersal ability, access to different resources, and the opportunity to settle in suitable habitats upon the trigger of environmental cues at key developmental moments. However, free-dispersing larvae can be highly sensitive to environmental changes. Among these, the magnitude and the occurrence of elevated carbon dioxide (CO2) concentrations in oceanic habitats is predicted to exacerbate over the next decades, particularly in coastal areas, reaching levels beyond those historically experienced by most marine organisms. Here, we aimed to determine the sensitivity to elevated pCO2 of successive life stages of a marine invertebrate species with a bentho-pelagic life cycle, exposed continuously during its early ontogeny, whilst providing in-depth insights on their metabolic responses. We selected, as an ideal study species, the American lobster Homarus americanus, and investigated life history traits, whole-organism physiology, and metabolomic fingerprints from larval stage I to juvenile stage V exposed to different pCO2 levels. Current and future ocean acidification scenarios were tested, as well as extreme high pCO2/low pH conditions that are predicted to occur in coastal benthic habitats and with leakages from underwater carbon capture storage (CCS) sites. Larvae demonstrated greater tolerance to elevated pCO2, showing no significant changes in survival, developmental time, morphology, and mineralisation, although they underwent intense metabolomic reprogramming. Conversely, juveniles showed the inverse pattern, with a reduction in survival and an increase in development time at the highest pCO2 levels tested, with no indication of metabolomic reprogramming. Metabolomic sensitivity to elevated pCO2 increased until metamorphosis (between larval and juvenile stages) and decreased afterward, suggesting this transition as a metabolic keystone for marine invertebrates with complex life cycles.

scholarly journals Analysis of a non-linear model of populations structured by size

2020 ◽  
Vol 101 (3) ◽  
pp. 734-750
Author(s):  
Anna Lo Grasso ◽  
Silvia Totaro
Keyword(s):  
Linear Model ◽  
Strong Solution ◽  
Mild Solution ◽  
Existence And Uniqueness ◽  
Marine Invertebrates ◽  
Life Stage ◽  
Pelagic Larvae ◽  
Non Linear ◽  
Local Habitat

AbstractThe model we study deals with a population of marine invertebrates structured by size whose life stage is composed of adults and pelagic larvae such as barnacles contained in a local habitat. We prove existence and uniqueness of a continuous positive global mild solution and we give an estimate of it. We prove also that this solution is the strong solution of the problem.

scholarly journals Late Pleistocene glacial–interglacial shell-size–isotope variability in planktonic foraminifera as a function of local hydrography

2015 ◽  
Vol 12 (15) ◽  
pp. 4781-4807 ◽  
Author(s):  
B. Metcalfe ◽  
W. Feldmeijer ◽  
M. de Vringer-Picon ◽  
G.-J. A. Brummer ◽  
F. J. C. Peeters ◽  
...  
Keyword(s):  
Size Range ◽  
North Atlantic Ocean ◽  
Life Stage ◽  
Planktonic Foraminifera ◽  
Isotope Analysis ◽  
Past Research ◽  
Individual Species ◽  
Shell Size ◽  
Size Fractions ◽  
Water Column Stratification

Abstract. So-called "vital effects" are a collective term for a suite of physiologically and metabolically induced variability in oxygen (δ18O) and carbon (δ13C) isotope ratios of planktonic foraminifer shells that hamper precise quantitative reconstruction of past ocean parameters. Correction for potential isotopic offsets from equilibrium or the expected value is paramount, as too is the ability to define a comparable life stage for each species that allows for direct comparison. Past research has focused upon finding a specific size range for individual species in lieu of other identifiable features, thus allowing ocean parameters from a particular constant (i.e. a specific depth or season) to be reconstructed. Single-shell isotope analysis of fossil shells from a mid-latitude North Atlantic Ocean piston core covering Termination III (200 to 250 ka) highlight the advantage of using a dynamic size range, i.e. utilising measurements from multiple narrow sieve size fractions spanning a large range of total body sizes, in studies of palaeoclimate. Using this methodology, we show that isotopic offsets between specimens in successive size fractions of Globorotalia inflata and Globorotalia truncatulinoides are not constant over time, contrary to previous findings. For δ18O in smaller-sized globorotalids (212–250 μm) it is suggested that the offset from other size fractions may reflect a shallower habitat in an early ontogenetic stage. A reduction in the difference between small and large specimens of G. inflata between insolation minima and maxima is interpreted to relate to a prolonged period of reduced water column stratification. For the shallow-dwelling species Globigerina bulloides, no size–isotope difference between size fractions is observed, and the variability in the oxygen isotopic values is shown to correlate well with the seasonal insolation patterns. As such, patterns in oxygen isotope variability of fossil populations may be used to reconstruct past seasonality changes.

Comparison Between API 579-1/ASME FFS-1 and ASME VIII Division 3 Stress Intensity Factor Solutions Used for Fracture Mechanics and Fatigue Analysis of Thick Walled Cylinders

2008 ◽  
Author(s):  
Jan G. M. Keltjens
Keyword(s):  
Stress Intensity Factor ◽  
Fatigue Crack ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Life Time ◽  
Time Study ◽  
Worked Example ◽  
Failure Assessment ◽  
Section Viii ◽  
Burst Analysis

The paper discusses the differences between API 579-1/ASME FFS-1-1/ASME FFS-1 [1] and ASME Section VIII Division 3 [2] stress intensity factor solutions. In addition to this, the use of the Failure Assessment Diagram (FAD) in leak before burst analysis is compared to the present Division 3 approach. The paper contains the background of both approaches and a worked example demonstrating the effect of both methods. Finally, a simplified fatigue crack growth based life time study is presented.

scholarly journals Late Pleistocene Glacial–Interglacial related shell size isotope variability in planktonic foraminifera as a function of local hydrology

2015 ◽  
Vol 12 (1) ◽  
pp. 135-189 ◽  
Author(s):  
B. Metcalfe ◽  
W. Feldmeijer ◽  
M. de Vringer-Picon ◽  
G.-J. A. Brummer ◽  
F. J. C. Peeters ◽  
...  
Keyword(s):  
Size Range ◽  
North Atlantic Ocean ◽  
Life Stage ◽  
Planktonic Foraminifera ◽  
Isotope Analysis ◽  
Past Research ◽  
Individual Species ◽  
Shell Size ◽  
Size Fractions ◽  
Water Column Stratification

Abstract. So called "vital effects", a collective noun for a suite of physiological and metabolic induced variability, in oxygen (δ18O) and carbon (δ13C) isotope ratios of planktonic foraminifer shells hamper precise quantitative reconstruction of past ocean parameters. Correction for potential isotopic offsets from the equilibrium or the expected value is paramount, as too is the ability to define a comparable life-stage for each species that allows for direct comparison. Past research has focused upon finding a specific size range for individual species in lieu of other identifiable features, that allow ocean parameters from a particular constant (i.e. a specific depth or season) to be reconstructed. Single shell isotope analysis of fossil shells from a mid-latitude North Atlantic Ocean piston-core covering Termination III (200 to 250 kyr) highlight the advantage of using a dynamic size range in studies of palaeoclimate. Using this methodology, we show that isotopic offsets between specimens in successive size fractions of G. inflata and G. truncatulinoides are not constant over time, contrary to previous findings. For δ18O in smaller sized globorotalids it is suggested that the offset from other size fractions may reflect a shallower habitat in an early ontogenetic stage. A reduction in the difference between small and large specimens of G. inflata between insolation minima and maxima is interpreted to relate to a prolonged period of reduced water column stratification. For the shallow dwelling species G. bulloides no size isotope difference between size fractions is observed, and the variability in the oxygen isotopic values are shown to correlate well with the seasonal insolation patterns. As such, patterns in oxygen isotope variability of fossil populations may be used successfully for reconstruction of past seasonality changes.

scholarly journals Soil microbes increase switchgrass germination but not seedling growth under drought

2021 ◽  
Author(s):  
Tayler Ulbrich ◽  
Lukas Bell-Dereske ◽  
Harry Ervin ◽  
Shanna Hilborn ◽  
Sarah E. Evans
Keyword(s):  
Plant Growth ◽  
Seedling Growth ◽  
Soil Microbes ◽  
Early Stage ◽  
Life Stage ◽  
Soil Microbial Communities ◽  
Bulk Soil ◽  
Plant Responses ◽  
Ambient Conditions ◽  
Precipitation Regimes

Abstract Purpose Soil microbial communities can mitigate the negative effects of drought on early-stage plant growth. However, the magnitude of this benefit may depend on both the microbial community’s previous host associations and the plant’s developmental stage.Methods We conducted a greenhouse experiment to investigate how microbial presence (autoclaved bulk vs. live bulk soils) and the microbial community’s association history (bulk soil vs. rhizosphere soil) affect germination and seedling growth during drought, as well as how drought and life-stage alter the assembly of the inoculated communities. Our focal plant was switchgrass (Panicum virgatum), a target bioenergy crop frequently used in native prairie restorations.Results We found that drought reduced growth by 59% and germination by 41% compared to ambient conditions, and that microbial presence altered drought responses. Seeds with microbes (live bulk soil) had 83% greater germination and 72% higher survival than seeds in autoclaved soils, and these effects were similar under both precipitation regimes. In contrast to microbial presence, the inoculated communities’ association history did not affect plant responses. We did find that plant growth-stage altered bacterial community assembly; bulk and rhizosphere bacterial communities were initially similar, and responded similarly to drought, but they diverged at the end of the experiment only with a germinating seed.Conclusion We show that soil microbes can increase germination and mitigate early-stage drought stress but that microbial association history may not strongly affect plant drought responses. Furthermore, interactions between soil community history and germination may be a critical, yet understudied, driver of microbiome assembly.

scholarly journals Effects of elevated CO<sub>2</sub> and temperature on phytoplankton community biomass, species composition and photosynthesis during an autumn bloom in the Western English Channel

2017 ◽  
Author(s):  
Matthew Keys ◽  
Gavin Tilstone ◽  
Helen S. Findlay ◽  
Claire E. Widdicombe ◽  
Tracy Lawson
Keyword(s):  
Elevated Temperature ◽  
Phytoplankton Community ◽  
Fold Increase ◽  
Elevated Pco2 ◽  
Total Biomass ◽  
Combined Effects ◽  
English Channel ◽  
Ambient Conditions ◽  
Phytoplankton Productivity ◽  
Community Biomass

Abstract. The combined effects of elevated pCO2 and temperature were investigated during an autumn phytoplankton bloom in the Western English Channel (WEC). A full factorial 36-day microcosm experiment was conducted under year 2100 predicted temperature (+4.5 °C) and pCO2 levels (800 μatm). The starting phytoplankton community biomass was 110.2 (±5.7 sd) mg carbon (C) m−3 and was dominated by dinoflagellates (~ 50 %) with smaller contributions from nanophytoplankton (~ 13 %), cryptophytes (~ 11 %)and diatoms (~ 9 %). Over the experimental period total biomass was significantly increased by elevated pCO2 (20-fold increase) and elevated temperature (15-fold increase). In contrast, the combined influence of these two factors had little effect on biomass relative to the ambient control. The phytoplankton community structure shifted from dinoflagellates to nanophytoplankton at the end of the experiment in all treatments. Under elevated pCO2 nanophytoplankton contributed 90% of community biomass and was dominated by Phaeocystis spp., while under elevated temperature nanophytoplankton contributed 85 % of the community biomass and was dominated by smaller nano-flagellates. Under ambient conditions larger nano-flagellates dominated while the smallest nanophytoplankton contribution was observed under combined elevated pCO2 and temperature (~ 40 %). Dinoflagellate biomass declined significantly under the individual influences of elevated pCO2, temperature and ambient conditions. Under the combined effects of elevated pCO2 and temperature, dinoflagellate biomass almost doubled from the starting biomass and there was a 30-fold increase in the harmful algal bloom (HAB) species, Prorocentrum cordatum. Chlorophyll a normalised maximum photosynthetic rates (PBm) increased > 6-fold under elevated pCO2 and > 3-fold under elevated temperature while no effect on PBm was observed when pCO2 and temperature were elevated simultaneously. The results suggest that future increases in temperature and pCO2 do not appear to influence coastal phytoplankton productivity during autumn in the WEC which would have a negative feedback on atmospheric CO2.

scholarly journals Metabolic recovery and compensatory shell growth of juvenile Pacific geoduck Panopea generosa following short-term exposure to acidified seawater

2020 ◽  
Vol 8 (1) ◽  
Author(s):  
Samuel J Gurr ◽  
Brent Vadopalas ◽  
Steven B Roberts ◽  
Hollie M Putnam
Keyword(s):  
Respiration Rate ◽  
Shell Length ◽  
Shell Growth ◽  
Common Garden ◽  
Elevated Pco2 ◽  
Ambient Conditions ◽  
Short Term ◽  
Metabolic Recovery ◽  
Short Term Exposure ◽  
Stress Conditioning

Abstract While acute stressors can be detrimental, environmental stress conditioning can improve performance. To test the hypothesis that physiological status is altered by stress conditioning, we subjected juvenile Pacific geoduck, Panopea generosa, to repeated exposures of elevated pCO2 in a commercial hatchery setting followed by a period in ambient common garden. Respiration rate and shell length were measured for juvenile geoduck periodically throughout short-term repeated reciprocal exposure periods in ambient (~550 μatm) or elevated (~2400 μatm) pCO2 treatments and in common, ambient conditions, 5 months after exposure. Short-term exposure periods comprised an initial 10-day exposure followed by 14 days in ambient before a secondary 6-day reciprocal exposure. The initial exposure to elevated pCO2 significantly reduced respiration rate by 25% relative to ambient conditions, but no effect on shell growth was detected. Following 14 days in common garden, ambient conditions, reciprocal exposure to elevated or ambient pCO2 did not alter juvenile respiration rates, indicating ability for metabolic recovery under subsequent conditions. Shell growth was negatively affected during the reciprocal treatment in both exposure histories; however, clams exposed to the initial elevated pCO2 showed compensatory growth with 5.8% greater shell length (on average between the two secondary exposures) after 5 months in ambient conditions. Additionally, clams exposed to the secondary elevated pCO2 showed 52.4% increase in respiration rate after 5 months in ambient conditions. Early exposure to low pH appears to trigger carryover effects suggesting bioenergetic re-allocation facilitates growth compensation. Life stage-specific exposures to stress can determine when it may be especially detrimental, or advantageous, to apply stress conditioning for commercial production of this long-lived burrowing clam.

Adult exposure to ocean acidification and warming remains beneficial for oyster larvae following starvation

2021 ◽  
Author(s):  
Mitchell C Gibbs ◽  
Laura M Parker ◽  
Elliot Scanes ◽  
Maria Byrne ◽  
Wayne A O’Connor ◽  
...  
Keyword(s):  
Climate Change ◽  
Lipid Content ◽  
Total Lipid Content ◽  
Marine Species ◽  
Elevated Pco2 ◽  
Transgenerational Plasticity ◽  
Beneficial Effects ◽  
Parental Exposure ◽  
Saccostrea Glomerata ◽  
Adult Exposure

Abstract Climate change is expected to warm and acidify oceans and alter the phenology of phytoplankton, creating a mismatch between larvae and their food. Transgenerational plasticity (TGP) may allow marine species to acclimate to climate change; however, it is expected that this may come with elevated energetic demands. This study used the oysters, Saccostrea glomerata and Crassostrea gigas, to test the effects of adult parental exposure to elevated pCO2 and temperature on larvae during starvation and recovery. It was anticipated that beneficial effects of TGP will be limited when larvae oyster are starved. Transgenerational responses and lipid reserves of larvae were measured for 2 weeks. Larvae of C. gigas and S. glomerata from parents exposed to elevated pCO2 had greater survival when exposed to elevated CO2, but this differed between species and temperature. For S. glomerata, survival of larvae was greatest when the conditions experienced by larvae matched the condition of their parents. For C. gigas, survival of larvae was greater when parents and larvae were exposed to elevated pCO2. Larvae of both species used lipids when starved. The total lipid content was dependent on parental exposure and temperature. Against expectations, the beneficial TGP responses of larvae remained, despite starvation.

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