scholarly journals Photosynthate translocation increases in response to low seawater pH in a coral–dinoflagellate symbiosis

2013 ◽  
Vol 10 (6) ◽  
pp. 3997-4007 ◽  
Author(s):  
P. Tremblay ◽  
M. Fine ◽  
J. F. Maguer ◽  
R. Grover ◽  
C. Ferrier-Pagès
Keyword(s):  
Scleractinian Coral ◽  
Carbon Budget ◽  
Coral Species ◽  
Environmental Changes ◽  
Low Ph ◽  
Total Carbon ◽  
Coral Host ◽  
Symbiotic Association ◽  
Stylophora Pistillata ◽  
Seawater Ph

Abstract. This study has examined the effect of low seawater pH values (induced by an increased CO2 partial pressure) on the rates of photosynthesis, as well as on the carbon budget and carbon translocation in the scleractinian coral species Stylophora pistillata, using a new model based on 13C labelling of the photosynthetic products. Symbiont photosynthesis contributes to a large part of the carbon acquisition in tropical coral species, and it is thus important to know how environmental changes affect this carbon acquisition and allocation. For this purpose, nubbins of S. pistillata were maintained for six months at two pHTs (8.1 and 7.2, by bubbling seawater with CO2). The lowest pH value was used to tackle how seawater pH impacts the carbon budget of a scleractinian coral. Rates of photosynthesis and respiration of the symbiotic association and of isolated symbionts were assessed at each pH. The fate of 13C photosynthates was then followed in the symbionts and the coral host for 48 h. Nubbins maintained at pHT 7.2 presented a lower areal symbiont concentration, and lower areal rates of gross photosynthesis and carbon incorporation compared to nubbins maintained at pHT 8.1. The total carbon acquisition was thus lower under low pH. However, the total percentage of carbon translocated to the host as well as the amount of carbon translocated per symbiont cell were significantly higher under pHT 7.2 than under pHT 8.1 (70% at pHT 7.2 vs. 60% at pHT 8.1), such that the total amount of photosynthetic carbon received by the coral host was equivalent under both pHs (5.5 to 6.1 μg C cm−2 h−1). Although the carbon budget of the host was unchanged, symbionts acquired less carbon for their own needs (0.6 compared to 1.8 μg C cm−2 h−1), explaining the overall decrease in symbiont concentration at low pH. In the long term, such decrease in symbiont concentration might severely affect the carbon budget of the symbiotic association.

scholarly journals Ocean acidification increases photosynthate translocation in a coral–dinoflagellates symbiosis

2013 ◽  
Vol 10 (1) ◽  
pp. 83-109 ◽  
Author(s):  
P. Tremblay ◽  
M. Fine ◽  
J. F. Maguer ◽  
R. Grover ◽  
C. Ferrier-Pagès
Keyword(s):  
Coral Species ◽  
Total Carbon ◽  
Coral Host ◽  
Climate Change Scenarios ◽  
Symbiotic Association ◽  
Stylophora Pistillata ◽  
Gross Photosynthesis ◽  
Total Percentage ◽  
Carbon Translocation ◽  
Tropical Coral

Abstract. This study has examined the effect of an increased seawater pCO2 on the rates of photosynthesis and carbon translocation in the scleractinian coral species Stylophora pistillata using a new model based on 13C-labelling of the photosynthetic products. Symbiont photosynthesis contributes for a large part of the carbon acquisition in tropical coral species and is therefore an important process that may determine their survival under climate change scenarios. Nubbins of S. pistillata were maintained for six months under two pHs (8.1 and 7.2). Rates of photosynthesis and respiration of the symbiotic association and of isolated symbionts were assessed at each pH. The fate of 13C-photosynthates was then followed in the symbionts and the coral host for 48 h. Nubbins maintained at pH 7.2 presented a lower areal symbiont concentration, lower areal rates of gross photosynthesis, and lower carbon incorporation rates compared to nubbins maintained at pH 8.1, therefore suggesting that the total carbon acquisition was lower in this first set of nubbins. However, the total percentage of carbon translocated to the host, as well as the amount of carbon translocated per symbiont cell was significantly higher under pH 7.2 than under pH 8.1 (70% at pH 7.2 versus 60% at pH 8.1), so that the total amount of photosynthetic carbon received by the coral host was equivalent under both pHs (5.5 to 6.1 μg C cm−2 h−1). Although the carbon budget of the host was unchanged, symbionts acquired less carbon for their own needs (0.6 against 1.8 μg C cm−2 h−1), explaining the overall decrease in symbiont concentration at low pH. In the long-term, this decrease might have important consequences for the survival of corals under an acidification stress.

scholarly journals Effect of feeding and thermal stress on photosynthesis, respiration and the carbon budget of the scleractinian coral Pocillopora damicornis

2018 ◽  
Author(s):  
Niclas Heidelberg Lyndby ◽  
Jacob Boiesen Holm ◽  
Daniel Wangpraseurt ◽  
Renaud Grover ◽  
Cécile Rottier ◽  
...  
Keyword(s):  
Thermal Stress ◽  
High Temperature ◽  
Carbon Budget ◽  
Limiting Factor ◽  
Coral Host ◽  
Symbiotic Association ◽  
Pocillopora Damicornis ◽  
Fixed Carbon ◽  
Heterogeneous Distribution ◽  
Macro Scale

AbstractStudying carbon dynamics in the coral holobiont provides essential knowledge of nutritional strategies and is thus central to understanding coral ecophysiology. In this study, the first aim was to investigate the effect of daily feeding and thermal stress on oxygen (O2) rates measured at polyp-scale with microsensors and at whole fragment scale using incubation methods. The second aim was to assess the carbon budget of the symbiotic association using H13CO3, under the different conditions. Micro- and macro-scale measurements revealed enhanced O2 evolution rates for fed compared to unfed corals. However, gross O2 production in fed corals was increased at high temperature on a macroscale but not on a microscale basis, likely due to a heterogeneous distribution of photosynthesis over the coral surface. Starved corals always exhibited reduced photosynthetic activity at high temperature, which suggests that the nutritional status of the coral host is a key limiting factor for coral productivity under thermal stress. Quantification of photosynthate translocation and carbon budgets showed very low incorporation rates, for both symbionts and host (0.03 - 0.6 μg C cm-2 h-1) equivalent to only 0.008 - 0.6 %, of the photosynthetically fixed carbon for P. damicornis, in all treatments. Carbon loss (via respiration and/or mucus release) was about 41 - 47 % and 52 - 76% of the fixed carbon for starved and fed corals, respectively. Such high loss of translocated carbon suggests that P. damicornis is nitrogen and/or phosphorus limited. Heterotrophy might thus cover a larger portion of the nutritional demand for P. damicornis than previously assumed. Our results suggest that active feeding plays a fundamental role in metabolic dynamics and bleaching susceptibility of corals.

scholarly journals Fatty Acid Profiles of Separated Host-Symbiont Fractions From Five Symbiotic Corals: Applications of Chemotaxonomic and Trophic Biomarkers

2021 ◽  
Author(s):  
TAIHUN KIM ◽  
David M. Baker ◽  
Se-Jong Ju ◽  
Jetty Chung-Yung Lee
Keyword(s):  
Trophic Level ◽  
Coral Species ◽  
Environmental Changes ◽  
Dry Weight ◽  
Data Interpretation ◽  
Host Tissue ◽  
Gas Chromatography Mass Spectrometry ◽  
Coral Host ◽  
Main Components ◽  
Species Specific

Abstract Fatty acids (FAs) are the main components of lipids in corals. We examined FA profiles from five symbiotic coral species belonging to five different genera (Acropora, Pavona, Turbinaria, Favites and Platygyra) and four different families (Acroporidae, Agariciidae, Dendrophyllidae, Faviidae). We separated symbionts from coral host tissue to investigate the interaction of FA between symbionts and host tissue. After separation, we used FA profiles, in particular specific FAs (e.g. 16:0, 18:0, 18:3n-3, 20:5n-3, 22:6n-3) and their ratios (EPA:DHA, PUFA:SFA) as biomarkers to examine chemotaxonomic indication and trophic level (autotrophy vs. heterotrophy) of each coral species. Gas chromatography-mass spectrometry (GC-MS) was performed to identify and quantify FA. For quantification, the dry weight of total lipids was used to normalize FA concentration (μg mg-1). We found that 1) FA profiles and their abundance in coral host tissue and symbionts are distinct (with the exception of autotrophic species) 2) our five different coral species are defined by species-specific FA profiles, 3) certain FAs are useful biomarkers to determine relative trophic strategies (i.e. autotrophy and/or heterotrophy, 4) the application of FA ratios to define trophic level requires caution in research application and data interpretation. Considering the limitations of FA ratios determined herein, we suggest it to be more appropriate if these FA ratios were only applied to examine response to environmental change within species. Going forward, our study provides important FA baseline data that builds the foundation to future investigations on impacts of environmental changes on nutrition and metabolism in symbiotic corals.

Transfer of photosynthetically fixed carbon between the prokaryotic green alga Prochloron and its ascidian host

1983 ◽  
Vol 34 (3) ◽  
pp. 431 ◽  
Author(s):  
DJ Griffiths ◽  
L Thinh
Keyword(s):  
Light Intensity ◽  
Green Alga ◽  
Host Tissue ◽  
Total Carbon ◽  
Symbiotic Association ◽  
Fixed Carbon ◽  
Low Light ◽  
Ascidian Species ◽  
Dark Fixation ◽  
Efficient Transfer

In the symbiotic association between the prokaryotic green alga Prochloron and three didemnid host species (Diplosoma similis, Lissoclinum bistratum, Trididemnum cyclops), between 6 and 51 % of the total carbon fixed during exposure for 1 h to H14CO3- in the light (150 �E m-2 s-1) becomes associated with the host tissue. Dark fixation of 14CO2 in these ascidian species and in Lissoclinum punctatum never exceeds 6% of photosynthetic fixation at saturating light intensity. The corresponding values for dark fixation of 14CO2 in isolated Prochloron cells fall within the same range. There is very little excretion of photosynthate from whole colonies of the above ascidian species nor from Didemnum molle, Lissoclinum voeltzkowi and Trididemnum miniatum (usually less than 1 % of total photosynthate at saturation light intensity), suggesting an efficient transfer mechanism from Prochloron to host. Evidence from pulse-chase experiments suggests that transfer probably involves the early products of photosynthesis. The extent of transfer of photosynthate between Prochloron and T. cyclops varies with the rate of photosynthetic 14CO2 fixation into the whole colony but there is some transfer even at low light intensities, which strongly limit photosynthesis.

Measuring Coral Skeletal Architecture Using Image Analysis v1

2021 ◽  
Author(s):  
Rowan Mclachlan ◽  
Ashruti Patel ◽  
Andrea G Grottoli
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Image Analysis ◽  
Scleractinian Coral ◽  
Coral Species ◽  
Energy Materials ◽  
Simple Method ◽  
Coral Skeletons ◽  
Skeletal Structures ◽  
Scanning Electron

Coral morphology is influenced by genetics, the environment, or the interaction of both, and thus is highly variable. This protocol outlines a non-destructive and relatively simple method for measuring Scleractinian coral sub-corallite skeletal structures (such as the septa length, theca thickness, and corallite diameter, etc.) using digital images produced as a result of digital microscopy or from scanning electron microscopy. This method uses X and Y coordinates of points placed onto photomicrographs to automatically calculate the length and/or diameter of a variety of sub-corallite skeletal structures in the Scleractinian coral Porites lobata. However, this protocol can be easily adapted for other coral species - the only difference may be the specific skeletal structures that are measured (for example, not all coral species have a pronounced columella or pali, or even circular corallites). This protocol is adapted from the methods described in Forsman et al. (2015) & Tisthammer et al. (2018). There are 4 steps to this protocol: 1) Removal of Organic Tissue from Coral Skeletons 2) Imaging of Coral Skeletons 3) Photomicrograph Image Analysis 4) Calculation of Corallite Microstructure Size This protocol was written by Dr. Rowan McLachlan and was reviewed by Ashruti Patel and Dr. Andréa Grottoli. Acknowledgments Leica DMS 1000 and Scanning Electron Microscopy photomicrographs used in this protocol were acquired at the Subsurface Energy Materials Characterization and Analysis Laboratory (SEMCAL), School of Earth Sciences at The Ohio State University, Ohio, USA. I would like to thank Dr. Julie Sheets, Dr. Sue Welch, and Dr. David Cole for training me on the use of these instruments.

scholarly journals The Australian terrestrial carbon budget

2012 ◽  
Vol 9 (9) ◽  
pp. 12259-12308 ◽  
Author(s):  
V. Haverd ◽  
M. R. Raupach ◽  
P. R. Briggs ◽  
J. G. Canadell ◽  
S. J. Davis ◽  
...  
Keyword(s):  
Fossil Fuels ◽  
Carbon Budget ◽  
Fossil Fuel ◽  
Net Primary Production ◽  
Total Carbon ◽  
Regional Studies ◽  
Australian Continent ◽  
The Mean ◽  
Riverine Export ◽  
Fossil Fuel Emissions

Abstract. This paper reports a study of the full carbon (C-CO2) budget of the Australian continent, focussing on 1990–2011 in the context of estimates over two centuries. The work is a contribution to the RECCAP (REgional Carbon Cycle Assessment and Processes) project, as one of numerous regional studies being synthesised in RECCAP. In constructing the budget, we estimate the following component carbon fluxes: Net Primary Production (NPP); Net Ecosystem Production (NEP); fire; Land Use Change (LUC); riverine export; dust export; harvest (wood, crop and livestock) and fossil fuel emissions (both territorial and non-territorial). The mean NEP reveals that climate variability and rising CO2 contributed 12 ± 29 (1σ error on mean) and 68 ± 35 Tg C yr−1 respectively. However these gains were partially offset by fire and LUC (along with other minor fluxes), which caused net losses of 31 ± 5 Tg C yr−1 and 18 ± 7 Tg C yr−1 respectively. The resultant Net Biome Production (NBP) of 31 ± 35 Tg C yr−1 offset fossil fuel emissions (95 ± 6 Tg C yr−1) by 32 ± 36%. The interannual variability (IAV) in the Australian carbon budget exceeds Australia's total carbon emissions by fossil fuel combustion and is dominated by IAV in NEP. Territorial fossil fuel emissions are significantly smaller than the rapidly growing fossil fuel exports: in 2009–2010, Australia exported 2.5 times more carbon in fossil fuels than it emitted by burning fossil fuels.

Organic matrix synthesis in the scleractinian coral stylophora pistillata: role in biomineralization and potential target of the organotin tributyltin

1998 ◽  
Vol 201 (13) ◽  
pp. 2001-2009 ◽  
Author(s):  
D Allemand ◽  
É Tambutté ◽  
JP Girard ◽  
J Jaubert
Keyword(s):  
Protein Synthesis ◽  
Aspartic Acid ◽  
Scleractinian Coral ◽  
Organic Matrix ◽  
Coral Skeleton ◽  
Matrix Proteins ◽  
Coral Tissue ◽  
Lag Phase ◽  
Acid Uptake ◽  
Stylophora Pistillata

The kinetics of organic matrix biosynthesis and incorporation into scleractinian coral skeleton was studied using microcolonies of Stylophora pistillata. [14C]Aspartic acid was used to label the organic matrix since this acidic amino acid can represent up to 50 mol % of organic matrix proteins. External aspartate was rapidly incorporated into tissue protein without any detectable lag phase, suggesting either a small intracellular pool of aspartic acid or a pool with a fast turn-over rate. The incorporation of 14C-labelled macromolecules into the skeleton was linear over time, after an initial delay of 20 min. Rates of calcification, measured by the incorporation of 45Ca into the skeleton, and of organic matrix biosynthesis and incorporation into the skeleton were constant. Inhibition of calcification by the Ca2+ channel inhibitor verapamil reduced the incorporation of organic matrix proteins into the skeleton. Similarly, organic matrix incorporation into the skeleton, but not protein synthesis for incorporation into the tissue compartment, was dependent on the state of polymerization of both actin and tubulin, as shown by the sensitivity of this process to cytochalasin B and colchicin. These drugs may inhibit exocytosis of organic matrix proteins into the subcalicoblastic space. Finally, inhibition of protein synthesis by emetin or cycloheximide and inhibition of N-glycosylation by tunicamycin reduced both the incorporation of macromolecules into the skeleton and the rate of calcification. This suggests that organic matrix biosynthesis and its migration towards the site of calcification may be a prerequisite step in the calcification process. On the basis of these results, we investigated the effects of tributyltin (TBT), a component of antifouling painting known to interfere with biomineralization processes. Our results have shown that this xenobiotic significantly inhibits protein synthesis and the subsequent incorporation of protein into coral skeleton. This effect was correlated with a reduction in the rate of calcification. Protein synthesis was shown to be the parameter most sensitive to TBT (IC50=0.2 micromol l-1), followed by aspartic acid uptake by coral tissue (IC50=0.6 micromol l-1), skeletogenesis (IC50=3 micromol l-1) and Ca2+ uptake by coral tissue (IC50=20 micromol l-1). These results suggest that the mode of action of TBT on calcification may be the inhibition of organic matrix biosynthesis.

scholarly journals Acid–base physiology over tidal periods in the mussel Mytilus edulis : size and temperature are more influential than seawater pH

2019 ◽  
Vol 286 (1897) ◽  
pp. 20182863 ◽  
Author(s):  
Stephanie Mangan ◽  
Rod W. Wilson ◽  
Helen S. Findlay ◽  
Ceri Lewis
Keyword(s):  
Mytilus Edulis ◽  
Environmental Changes ◽  
Interactive Effect ◽  
Marine Biota ◽  
Acid Base ◽  
Tidal Cycles ◽  
Seawater Ph ◽  
Seawater Carbonate Chemistry ◽  
Two Populations

Ocean acidification (OA) studies to date have typically used stable open-ocean pH and CO 2 values to predict the physiological responses of intertidal species to future climate scenarios, with few studies accounting for natural fluctuations of abiotic conditions or the alternating periods of emersion and immersion routinely experienced during tidal cycles. Here, we determine seawater carbonate chemistry and the corresponding in situ haemolymph acid–base responses over real time for two populations of mussel ( Mytilus edulis ) during tidal cycles, demonstrating that intertidal mussels experience daily acidosis during emersion. Using these field data to parameterize experimental work we demonstrate that air temperature and mussel size strongly influence this acidosis, with larger mussels at higher temperatures experiencing greater acidosis. There was a small interactive effect of prior immersion in OA conditions (pH NBS 7.7/pCO 2 930 µatm) such that the haemolymph pH measured at the start of emersion was lower in large mussels exposed to OA. Critically, the acidosis induced in mussels during emersion in situ was greater (ΔpH approximately 0.8 units) than that induced by experimental OA (ΔpH approximately 0.1 units). Understanding how environmental fluctuations influence physiology under current scenarios is critical to our ability to predict the responses of key marine biota to future environmental changes.

scholarly journals Electrophysiological evidence for light-activated cation transport in calcifying corals

2019 ◽  
Vol 286 (1896) ◽  
pp. 20182444 ◽  
Author(s):  
Isabelle Taubner ◽  
Marian Y. Hu ◽  
Anton Eisenhauer ◽  
Markus Bleich
Keyword(s):  
Ion Transport ◽  
Ussing Chamber ◽  
Light Response ◽  
Coral Host ◽  
Hermatypic Coral ◽  
Stylophora Pistillata ◽  
Hermatypic Corals ◽  
Net Flux ◽  
Endosymbiotic Algae ◽  
Microelectrode Measurements

Light has been demonstrated to enhance calcification rates in hermatypic coral species. To date, it remains unresolved whether calcifying epithelia change their ion transport activity during illumination, and whether such a process is mediated by the endosymbiotic algae or can be controlled by the coral host itself. Using a modified Ussing chamber in combination with H + sensitive microelectrode measurements, the present work demonstrates that light triggers the generation of a skeleton positive potential of up to 0.9 mV in the hermatypic coral Stylophora pistillata . This potential is generated by a net flux of cations towards the skeleton and reaches its maximum at blue (450 nm) light. The effects of pharmacological inhibitors targeting photosynthesis 3-(3,4-dichlorophenyl)-1,1-dimethylurea (DCMU) and anion transport 4,4'-diisothiocyano-2,2'-stilbenedisulfonic acid (DIDS) were investigated by pH microelectrode measurements in coral tissues demonstrating a rapid decrease in tissue pH under illumination. However, these inhibitors showed no effect on the electrophysiological light response of the coral host. By contrast, metabolic inhibition by cyanide and deoxyglucose reversibly inhibited the light-induced cation flux towards the skeleton. These results suggest that ion transport across coral epithelia is directly triggered by blue light, independent of photosynthetic activity of algal endosymbionts. Measurements of this very specific and quantifiable physiological response can provide parameters to identify photoreception mechanisms and will help to broaden our understanding of the mechanistic link between light stimulation and epithelial ion transport, potentially relevant for calcification in hermatypic corals.

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