scholarly journals Effect of temperature and feeding on carbon budgets and O2 dynamics in Pocillopora damicornis

2020 ◽  
Vol 652 ◽  
pp. 49-62 ◽  
Author(s):  
NH Lyndby ◽  
JB Holm ◽  
D Wangpraseurt ◽  
R Grover ◽  
C Rottier ◽  
...  
Keyword(s):  
Photosynthetic Activity ◽  
Coral Tissue ◽  
Effect Of Temperature ◽  
Pocillopora Damicornis ◽  
Fixed Carbon ◽  
High Loss ◽  
Coral Holobiont ◽  
Essential Knowledge ◽  
Nutritional Strategies ◽  
Photosynthate Translocation

Studying carbon dynamics in the coral holobiont provides essential knowledge of nutritional strategies and is thus central to understanding coral ecophysiology. In this study, we assessed the carbon budget in Pocillopora damicornis (using H13CO3) as a function of feeding status and temperature stress. We also compared dissolved oxygen (O2) fluxes measured at the colony scale and at the polyp scale. At both scales, O2 production rates were enhanced for fed vs. unfed corals, and unfed corals exhibited higher bleaching and reduced photosynthetic activity at high temperature. Unfed corals exclusively respired autotrophically acquired carbon, while fed corals mostly respired heterotrophically acquired carbon. As a consequence, fed corals excreted on average >5 times more organic carbon than unfed corals. Photosynthate translocation was higher under thermal stress, but most of the carbon was lost via respiration and/or mucus release (42-46% and 57-75% of the fixed carbon for unfed and fed corals, respectively). Such high loss of translocated carbon, coupled to low assimilation rates in the coral tissue and symbionts, suggests that P. damicornis was 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.

Predicting cold-water bleaching in corals: role of temperature, and potential integration of light exposure

2020 ◽  
Vol 642 ◽  
pp. 133-146
Author(s):  
PC González-Espinosa ◽  
SD Donner
Keyword(s):  
Coral Bleaching ◽  
Cold Water ◽  
Light Exposure ◽  
Light Attenuation ◽  
Florida Keys ◽  
Cold Temperature ◽  
Warm Water ◽  
Coral Tissue ◽  
Effect Of Temperature ◽  
Type I

Warm-water growth and survival of corals are constrained by a set of environmental conditions such as temperature, light, nutrient levels and salinity. Water temperatures of 1 to 2°C above the usual summer maximum can trigger a phenomenon known as coral bleaching, whereby disruption of the symbiosis between coral and dinoflagellate micro-algae, living within the coral tissue, reveals the white skeleton of coral. Anomalously cold water can also lead to coral bleaching but has been the subject of limited research. Although cold-water bleaching events are less common, they can produce similar impacts on coral reefs as warm-water events. In this study, we explored the effect of temperature and light on the likelihood of cold-water coral bleaching from 1998-2017 using available bleaching observations from the Eastern Tropical Pacific and the Florida Keys. Using satellite-derived sea surface temperature, photosynthetically available radiation and light attenuation data, cold temperature and light exposure metrics were developed and then tested against the bleaching observations using logistic regression. The results show that cold-water bleaching can be best predicted with an accumulated cold-temperature metric, i.e. ‘degree cooling weeks’, analogous to the heat stress metric ‘degree heating weeks’, with high accuracy (90%) and fewer Type I and Type II errors in comparison with other models. Although light, when also considered, improved prediction accuracy, we found that the most reliable framework for cold-water bleaching prediction may be based solely on cold-temperature exposure.

scholarly journals Quantitative Characterization of Geotrichum candidum Growth in Milk

2021 ◽  
Vol 11 (10) ◽  
pp. 4619
Author(s):  
Petra Šipošová ◽  
Martina Koňuchová ◽  
Ľubomír Valík ◽  
Monika Trebichavská ◽  
Alžbeta Medveďová
Keyword(s):  
Growth Parameters ◽  
Mechanistic Model ◽  
Geotrichum Candidum ◽  
Activity Level ◽  
Effect Of Temperature ◽  
Operational Parameters ◽  
Quantitative Characterization ◽  
Essential Knowledge ◽  
Cardinal Temperatures

The study of microbial growth in relation to food environments provides essential knowledge for food quality control. With respect to its significance in the dairy industry, the growth of Geotrichum candidum isolate J in milk without and with 1% NaCl was investigated under isothermal conditions ranging from 6 to 37 °C. The mechanistic model by Baranyi and Roberts was used to fit the fungal counts over time and to estimate the growth parameters of the isolate. The effect of temperature on the growth of G. candidum in milk was modelled with the cardinal models, and the cardinal temperatures were calculated as Tmin = −3.8–0.0 °C, Topt = 28.0–34.6 °C, and Tmax = 35.2–37.2 °C. The growth of G. candidum J was slightly faster in milk with 1% NaCl and in temperature regions under 21 °C. However, in a temperature range that was close to the optimum, its growth was slightly inhibited by the lowered water activity level. The present study provides useful cultivation data for understanding the behaviour of G. candidum in milk and can serve as an effective tool for assessing the risk of fungal spoilage, predicting the shelf life of dairy products, or assessing the optimal conditions for its growth in relation to the operational parameters in dairy practices.

scholarly journals Subcellular Investigation of Photosynthesis-Driven Carbon Assimilation in the Symbiotic Reef Coral Pocillopora damicornis

mBio ◽  
2015 ◽  
Vol 6 (1) ◽  
Author(s):  
Christophe Kopp ◽  
Isabelle Domart-Coulon ◽  
Stephane Escrig ◽  
Bruno M. Humbel ◽  
Michel Hignette ◽  
...  
Keyword(s):  
Lipid Droplets ◽  
Secondary Ion Mass Spectrometry ◽  
Reef Coral ◽  
Carbon Assimilation ◽  
Isotopic Labeling ◽  
Cellular Level ◽  
Coral Tissue ◽  
Pocillopora Damicornis ◽  
Carbon And Nitrogen ◽  
Transmission Electron

ABSTRACT  Reef-building corals form essential, mutualistic endosymbiotic associations with photosynthetic Symbiodinium dinoflagellates, providing their animal host partner with photosynthetically derived nutrients that allow the coral to thrive in oligotrophic waters. However, little is known about the dynamics of these nutritional interactions at the (sub)cellular level. Here, we visualize with submicrometer spatial resolution the carbon and nitrogen fluxes in the intact coral-dinoflagellate association from the reef coral Pocillopora damicornis by combining nanoscale secondary ion mass spectrometry (NanoSIMS) and transmission electron microscopy with pulse-chase isotopic labeling using [13C]bicarbonate and [15N]nitrate. This allows us to observe that (i) through light-driven photosynthesis, dinoflagellates rapidly assimilate inorganic bicarbonate and nitrate, temporarily storing carbon within lipid droplets and starch granules for remobilization in nighttime, along with carbon and nitrogen incorporation into other subcellular compartments for dinoflagellate growth and maintenance, (ii) carbon-containing photosynthates are translocated to all four coral tissue layers, where they accumulate after only 15 min in coral lipid droplets from the oral gastroderm and within 6 h in glycogen granules from the oral epiderm, and (iii) the translocation of nitrogen-containing photosynthates is delayed by 3 h. IMPORTANCE  Our results provide detailed in situ subcellular visualization of the fate of photosynthesis-derived carbon and nitrogen in the coral-dinoflagellate endosymbiosis. We directly demonstrate that lipid droplets and glycogen granules in the coral tissue are sinks for translocated carbon photosynthates by dinoflagellates and confirm their key role in the trophic interactions within the coral-dinoflagellate association.

scholarly journals Autotrophic carbon budget in coral tissue: a new 13C-based model of photosynthate translocation

2012 ◽  
Vol 215 (8) ◽  
pp. 1384-1393 ◽  
Author(s):  
P. Tremblay ◽  
R. Grover ◽  
J. F. Maguer ◽  
L. Legendre ◽  
C. Ferrier-Pages
Keyword(s):  
Carbon Budget ◽  
Coral Tissue ◽  
Photosynthate Translocation

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 Relative abundance of nitrogen cycling microbes in coral holobionts reflects environmental nitrate availability

2021 ◽  
Vol 8 (6) ◽  
pp. 201835
Author(s):  
Arjen Tilstra ◽  
Florian Roth ◽  
Yusuf C. El-Khaled ◽  
Claudia Pogoreutz ◽  
Nils Rädecker ◽  
...  
Keyword(s):  
Environmental Parameters ◽  
N Cycling ◽  
Coral Tissue ◽  
Gene Copy ◽  
Nitrate Availability ◽  
Copy Numbers ◽  
Coral Holobiont ◽  
Cell Densities ◽  
Gene Copy Numbers ◽  
Seasonal Shifts

Recent research suggests that nitrogen (N) cycling microbes are important for coral holobiont functioning. In particular, coral holobionts may acquire bioavailable N via prokaryotic dinitrogen (N 2 ) fixation or remove excess N via denitrification activity. However, our understanding of environmental drivers on these processes in hospite remains limited. Employing the strong seasonality of the central Red Sea, this study assessed the effects of environmental parameters on the proportional abundances of N cycling microbes associated with the hard corals Acropora hemprichii and Stylophora pistillata. Specifically, we quantified changes in the relative ratio between nirS and nifH gene copy numbers, as a proxy for seasonal shifts in denitrification and N 2 fixation potential in corals, respectively. In addition, we assessed coral tissue-associated Symbiodiniaceae cell densities and monitored environmental parameters to provide a holobiont and environmental context, respectively. While ratios of nirS to nifH gene copy numbers varied between seasons, they revealed similar seasonal patterns in both coral species, with ratios closely following patterns in environmental nitrate availability. Symbiodiniaceae cell densities aligned with environmental nitrate availability, suggesting that the seasonal shifts in nirS to nifH gene abundance ratios were probably driven by nitrate availability in the coral holobiont. Thereby, our results suggest that N cycling in coral holobionts probably adjusts to environmental conditions by increasing and/or decreasing denitrification and N 2 fixation potential according to environmental nitrate availability. Microbial N cycling may, thus, extenuate the effects of changes in environmental nitrate availability on coral holobionts to support the maintenance of the coral–Symbiodiniaceae symbiosis.

scholarly journals Highly Variable and Non-complex Diazotroph Communities in Corals From Ambient and High CO2 Environments

2021 ◽  
Vol 8 ◽  
Author(s):  
Laura Geissler ◽  
Valentine Meunier ◽  
Nils Rädecker ◽  
Gabriela Perna ◽  
Riccardo Rodolfo-Metalpa ◽  
...  
Keyword(s):  
Relative Abundance ◽  
Coral Species ◽  
Amplicon Sequencing ◽  
Pocillopora Damicornis ◽  
Bacterial Assemblage ◽  
Galaxea Fascicularis ◽  
Coral Holobiont ◽  
Community Assemblages ◽  
Community Variability ◽  
Family Rhodobacteraceae

The ecological success of corals depends on their association with microalgae and a diverse bacterial assemblage. Ocean acidification (OA), among other stressors, threatens to impair host-microbial metabolic interactions that underlie coral holobiont functioning. Volcanic CO2 seeps offer a unique opportunity to study the effects of OA in natural reef settings and provide insight into the long-term adaptations under a low pH environment. Here we compared nitrogen-fixing bacteria (diazotrophs) associated with four coral species (Pocillopora damicornis, Galaxea fascicularis, Acropora secale, and Porites rus) collected from CO2 seeps at Tutum Bay (Papua New Guinea) with those from a nearby ambient CO2 site using nifH amplicon sequencing to characterize the effects of seawater pH on bacterial communities and nitrogen cycling. Diazotroph communities were of generally low diversity across all coral species and for both sampling sites. Out of a total of 25 identified diazotroph taxa, 14 were associated with P. damicornis, of which 9 were shared across coral species. None of the diazotroph taxa, however, were consistently found across all coral species or across all samples within a species pointing to a high degree of diazotroph community variability. Rather, the majority of sampled colonies were dominated by one or two diazotroph taxa of high relative abundance. Pocillopora damicornis and Galaxea fascicularis that were sampled in both environments showed contrasting community assemblages between sites. In P. damicornis, Gammaproteobacteria and Cyanobacteria were prevalent under ambient pCO2, while a single member of the family Rhodobacteraceae was present at high relative abundance at the high pCO2 site. Conversely, in G. fascicularis diazotroph communities were indifferent between both sites. Diazotroph community changes in response to OA seem thus variable within as well as between host species, potentially arguing for haphazard diazotroph community assembly. This warrants further research into the underlying factors structuring diazotroph community assemblages and their functional role in the coral holobiont.

scholarly journals Rapid Recruitment of Symbiotic Algae into Developing Scleractinian Coral Tissues

2019 ◽  
Vol 7 (9) ◽  
pp. 306
Author(s):  
Bockel ◽  
Rinkevich
Keyword(s):  
Tissue Expansion ◽  
Outer Edge ◽  
Tissue Growth ◽  
Coral Tissue ◽  
Coral Host ◽  
Pocillopora Damicornis ◽  
Stylophora Pistillata ◽  
Symbiotic Algae ◽  
Glass Slides ◽  
Host Tissues

While the early acquisition of Symbiodiniaceae algae into coral host tissues has been extensively studied, the dynamics of the migration of algal cells into rapidly expanding coral tissues still lacks a systematic study. This work examined two Red Sea branching coral species, Pocillopora damicornis and Stylophora pistillata, as they were growing and expanding their tissue laterally on glass slides (January–June, 2014; 450 assays; five colonies/species). We measured lateral tissue expansion rates and intratissue dinoflagellate migration rates. Tissue growth rates significantly differed between the two species (with Stylophora faster than Pocillopora), but not between genotypes within a species. Using a “flow-through coral chamber” under the microscope, the migration of dinoflagellates towards the peripheral edges of the expanding coral tissue was quantified. On a five-day timescale, the density of the endosymbiotic dinoflagellate cells, presenting within a 90 µm region of expanding coral tissue (outer edge), increased by a factor of 23.6 for Pocillopora (from 1.2 × 104 cells cm‒² to 2.4 × 105 cells cm‒²) and by a factor of 6.8 for Stylophora (from 3.6 × 104 cells cm‒² to 2.4 × 105 cells cm‒²). The infection rates were fast (5.2 × 104 and 4.1 × 104 algal cells day-1 cm‒², respectively), further providing evidence of an as yet unknown pathway of algal movement within coral host tissues.

scholarly journals PEMBUATAN BRIKET DARI KULIT KAKAO MENGGUNAKAN PEREKAT KULIT UBI KAYU

2017 ◽  
Vol 6 (3) ◽  
pp. 21-27
Author(s):  
Rosta Natalia Sinaga ◽  
Rosdanelli Hasibuan
Keyword(s):  
Particle Size ◽  
Temperature Variation ◽  
Compaction Pressure ◽  
Strength Test ◽  
Raw Material ◽  
Effect Of Temperature ◽  
Fixed Carbon ◽  
Carbonization Process

This study aims to determine the effect of temperature variation carbonization, carbonization time and adhesive variation to charcoal characteristics of cocoa skin using cassava skin adhesive. Briquette is usually made using binder. Binder can embed charcoal each other to form strong and compact briquettes. Some other variables beside binder that influence the quality of briquettes include raw material, compacting presseure and carbonization process. This research used cocoa leather as raw material with cassava skin leaves as binder. All variables affect the content of fixed carbon of the briquettes that influence the caloricvalue of the briquettes. The caloricvalue is the most important factor for determining the quality of the briquettes. In this research, the highest caloricvalue of the briquettes was 4.375 cal/g. It was achieved when cocoa leather were carbonized by method 1 with compaction pressure of 85 kg/cm2 and binderconcentration of 15% where as raw material with  particle size of 100 mesh. The caloricvalue of the  briquettes was still very low and did not meet the qualification of Indonesian standard for briquettes. Based on the strength test, cassava skin leaves couldn’t be used as briquette’s binder. The produced briquettes that used cassava skin leaves as binder had soft structure and easily destroyed.

scholarly journals In vivoimaging of coral tissue and skeleton with optical coherence tomography

2016 ◽  
Author(s):  
Daniel Wangpraseurt ◽  
Camilla Wentzel ◽  
Steven L. Jacques ◽  
Michael Wagner ◽  
Michael Kuhl
Keyword(s):  
Optical Coherence Tomography ◽  
Surface Area ◽  
Fluorescent Protein ◽  
Coral Tissue ◽  
Optical Coherence ◽  
Pocillopora Damicornis ◽  
Dynamic Changes ◽  
Linear Contraction ◽  
Non Invasive

AbstractOptical coherence tomography (OCT) is a non-invasive three-dimensional imaging technique with micrometer resolution allowing microstructural characterization of tissuesin vivoand in real time. We present the first application of OCT forin vivoimaging of tissue and skeleton structure of intact living corals spanning a variety of morphologies and tissue thickness. OCT visualized different coral tissue layers (e.g. endoderm vs ectoderm), special structures such as mesenterial filaments and skeletal cavities, as well as mucus release from living corals. We also developed a new approach for non-invasive imaging and quantification of chromatophores containing green fluorescent protein (GFP)-like host pigment granules in coral tissue. The chromatophore system is hyper-reflective and can thus be imaged with good optical contrast in OCT, enabling quantification of chromatophore size, distribution and abundance. Because of its rapid imaging speed, OCT can also be used to quantify coral tissue movement showing that maximal linear contraction velocity was ~120 μm per second upon high light stimulation. Based on OCT imaging of tissue expansion and contraction, we made first estimates of dynamic changes in the coral tissue surface area, which varied by a factor of 2 between the contracted and expanded state of the coralPocillopora damicornis. We conclude that OCT is an excellent novel tool forin vivotomographic imaging of corals that can reveal tissue and skeleton organization as well as quantify dynamic changes in tissue structure and coral surface area non-invasively and at high spatio-temporal resolution.

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