scholarly journals Variation in sensitivity of large benthic Foraminifera to the combined effects of ocean warming and local impacts

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Martina Prazeres ◽  
T. Edward Roberts ◽  
John M. Pandolfi
Keyword(s):  
Benthic Foraminifera ◽  
Ocean Warming ◽  
Combined Effects ◽  
Large Benthic Foraminifera ◽  
Local Impacts

scholarly journals Vegetative Reproduction Is More Advantageous Than Sexual Reproduction in a Canopy-Forming Clonal Macroalga under Ocean Warming Accompanied by Oligotrophication and Intensive Herbivory

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1522
Author(s):  
Hikaru Endo ◽  
Toru Sugie ◽  
Yukiko Yonemori ◽  
Yuki Nishikido ◽  
Hikari Moriyama ◽  
...  
Keyword(s):  
Growth Rate ◽  
High Temperature ◽  
Nutrient Availability ◽  
Vegetative Reproduction ◽  
Ocean Warming ◽  
Regeneration Ability ◽  
Combined Effects ◽  
Regeneration Rate ◽  
Fish Herbivory ◽  
C 30

Ocean warming and the associated changes in fish herbivory have caused polarward distributional shifts in the majority of canopy-forming macroalgae that are dominant in temperate Japan, but have little effect on the alga Sargassum fusiforme. The regeneration ability of new shoots from holdfasts in this species may be advantageous in highly grazed environments. However, little is known about the factors regulating this in Sargassum species. Moreover, holdfast tolerance to high-temperature and nutrient-poor conditions during summer has rarely been evaluated. In the present study, S. fusiforme holdfast responses to the combined effects of temperature and nutrient availability were compared to those of sexually reproduced propagules. The combined effects of holdfast fragmentation and irradiance on regeneration were also evaluated. Propagule growth rate values changed from positive to negative under the combination of elevated temperature (20 °C–30 °C) and reduced nutrient availability, whereas holdfasts exhibited a positive growth rate even at 32 °C in nutrient-poor conditions. The regeneration rate increased with holdfast fragmentation (1 mm segments), but was unaffected by decreased irradiance. These results suggest that S. fusiforme holdfasts have a higher tolerance to high-temperature and nutrient-poor conditions during summer than propagules, and regenerate new shoots even if 1-mm segments remain in shaded refuges for fish herbivory avoidance.

scholarly journals Response of large benthic foraminifera to climate and local changes: Implications for future carbonate production

Sedimentology ◽  
2021 ◽  
Author(s):  
Gita R. Narayan ◽  
Claire E. Reymond ◽  
Marleen Stuhr ◽  
Steve Doo ◽  
Christiane Schmidt ◽  
...  
Keyword(s):  
Benthic Foraminifera ◽  
Carbonate Production ◽  
Large Benthic Foraminifera

scholarly journals Ocean acidification induces biochemical and morphological changes in the calcification process of large benthic foraminifera

2015 ◽  
Vol 282 (1803) ◽  
pp. 20142782 ◽  
Author(s):  
Martina Prazeres ◽  
Sven Uthicke ◽  
John M. Pandolfi
Keyword(s):  
Ocean Acidification ◽  
Benthic Foraminifera ◽  
Morphological Changes ◽  
Ambient Conditions ◽  
Skeletal Density ◽  
Buoyant Weight ◽  
Large Benthic Foraminifera ◽  
Sediment Formation ◽  
Ph Conditions ◽  
Main Factor

Large benthic foraminifera are significant contributors to sediment formation on coral reefs, yet they are vulnerable to ocean acidification. Here, we assessed the biochemical and morphological impacts of acidification on the calcification of Amphistegina lessonii and Marginopora vertebralis exposed to different pH conditions. We measured growth rates (surface area and buoyant weight) and Ca-ATPase and Mg-ATPase activities and calculated shell density using micro-computer tomography images. In A. lessonii , we detected a significant decrease in buoyant weight, a reduction in the density of inner skeletal chambers, and an increase of Ca-ATPase and Mg-ATPase activities at pH 7.6 when compared with ambient conditions of pH 8.1. By contrast, M. vertebralis showed an inhibition in Mg-ATPase activity under lowered pH, with growth rate and skeletal density remaining constant. While M. vertebralis is considered to be more sensitive than A. lessonii owing to its high-Mg-calcite skeleton, it appears to be less affected by changes in pH, based on the parameters assessed in this study. We suggest difference in biochemical pathways of calcification as the main factor influencing response to changes in pH levels, and that A. lessonii and M. vertebralis have the ability to regulate biochemical functions to cope with short-term increases in acidity.

scholarly journals Only as strong as the weakest link: structural analysis of the combined effects of elevated temperature and pCO2 on mussel attachment

2019 ◽  
Vol 7 (1) ◽  
Author(s):  
Laura A Newcomb ◽  
Matthew N George ◽  
Michael J O’Donnell ◽  
Emily Carrington
Keyword(s):  
Elevated Temperature ◽  
Structural Analysis ◽  
Structural Integrity ◽  
Proximal Region ◽  
Ocean Warming ◽  
Mode Analysis ◽  
Effect Of Temperature ◽  
High Pco2 ◽  
Combined Effects ◽  
Thread Strength

AbstractPredicting how combinations of stressors will affect failure risk is a key challenge for the field of ecomechanics and, more generally, ecophysiology. Environmental conditions often influence the manufacture and durability of biomaterials, inducing structural failure that potentially compromises organismal reproduction, growth, and survival. Species known for tight linkages between structural integrity and survival include bivalve mussels, which produce numerous byssal threads to attach to hard substrate. Among the current environmental threats to marine organisms are ocean warming and acidification. Elevated pCO2 exposure is known to weaken byssal threads by compromising the strength of the adhesive plaque. This study uses structural analysis to evaluate how an additional stressor, elevated temperature, influences byssal thread quality and production. Mussels (Mytilus trossulus) were placed in controlled temperature and pCO2 treatments, and then, newly produced threads were counted and pulled to failure to determine byssus strength. The effects of elevated temperature on mussel attachment were dramatic; mussels produced 60% weaker and 65% fewer threads at 25°C in comparison to 10°C. These effects combine to weaken overall attachment by 64–88% at 25°C. The magnitude of the effect of pCO2 on thread strength was substantially lower than that of temperature and, contrary to our expectations, positive at high pCO2 exposure. Failure mode analysis localized the effect of temperature to the proximal region of the thread, whereas pCO2 affected only the adhesive plaques. The two stressors therefore act independently, and because their respective target regions are interconnected (resisting tension in series), their combined effects on thread strength are exactly equal to the effect of the strongest stressor. Altogether, these results show that mussels, and the coastal communities they support, may be more vulnerable to the negative effects of ocean warming than ocean acidification.

scholarly journals Decrease in volume and density of foraminiferal shells with progressing ocean acidification

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Azumi Kuroyanagi ◽  
Takahiro Irie ◽  
Shunichi Kinoshita ◽  
Hodaka Kawahata ◽  
Atsushi Suzuki ◽  
...  
Keyword(s):  
Partial Pressure ◽  
Ocean Acidification ◽  
Benthic Foraminifera ◽  
Growth Parameters ◽  
Carbonate Production ◽  
Large Benthic Foraminifera ◽  
Seawater Ph ◽  
Ph Conditions ◽  
Calcification Process ◽  
The Tropics

AbstractRapid increases in anthropogenic atmospheric CO2 partial pressure have led to a decrease in the pH of seawater. Calcifying organisms generally respond negatively to ocean acidification. Foraminifera are one of the major carbonate producers in the ocean; however, whether calcification reduction by ocean acidification affects either foraminiferal shell volume or density, or both, has yet to be investigated. In this study, we cultured asexually reproducing specimens of Amphisorus kudakajimensis, a dinoflagellate endosymbiont-bearing large benthic foraminifera (LBF), under different pH conditions (pH 7.7–8.3, NBS scale). The results suggest that changes in seawater pH would affect not only the quantity (i.e., shell volume) but also the quality (i.e., shell density) of foraminiferal calcification. We proposed that pH and temperature affect these growth parameters differently because (1) they have differences in the contribution to the calcification process (e.g., Ca2+-ATPase and Ω) and (2) pH mainly affects calcification and temperature mainly affects photosynthesis. Our findings also suggest that, under the IPCC RCP8.5 scenario, both ocean acidification and warming will have a significant impact on reef foraminiferal carbonate production by the end of this century, even in the tropics.

scholarly journals Biodiversity of coral reef cryptobiota shuffles but does not decline under the combined stressors of ocean warming and acidification

2021 ◽  
Vol 118 (39) ◽  
pp. e2103275118
Author(s):  
Molly A. Timmers ◽  
Christopher P. Jury ◽  
Jan Vicente ◽  
Keisha D. Bahr ◽  
Maryann K. Webb ◽  
...  
Keyword(s):  
Species Richness ◽  
Community Structure ◽  
Coral Reef ◽  
Amplicon Sequencing ◽  
Ocean Warming ◽  
Control Treatment ◽  
Combined Effects ◽  
Community Interactions ◽  
Climate Conditions ◽  
Reef Communities

Ocean-warming and acidification are predicted to reduce coral reef biodiversity, but the combined effects of these stressors on overall biodiversity are largely unmeasured. Here, we examined the individual and combined effects of elevated temperature (+2 °C) and reduced pH (−0.2 units) on the biodiversity of coral reef communities that developed on standardized sampling units over a 2-y mesocosm experiment. Biodiversity and species composition were measured using amplicon sequencing libraries targeting the cytochrome oxidase I (COI) barcoding gene. Ocean-warming significantly increased species richness relative to present-day control conditions, whereas acidification significantly reduced richness. Contrary to expectations, species richness in the combined future ocean treatment with both warming and acidification was not significantly different from the present-day control treatment. Rather than the predicted collapse of biodiversity under the dual stressors, we find significant changes in the relative abundance but not in the occurrence of species, resulting in a shuffling of coral reef community structure among the highly species-rich cryptobenthic community. The ultimate outcome of altered community structure for coral reef ecosystems will depend on species-specific ecological functions and community interactions. Given that most species on coral reefs are members of the understudied cryptobenthos, holistic research on reef communities is needed to accurately predict diversity–function relationships and ecosystem responses to future climate conditions.

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