scholarly journals Tissue- and cellular-level allocation of autotrophic and heterotrophic nutrients in the coral symbiosis – A NanoSIMS study

2018 ◽  
Author(s):  
Thomas Krueger ◽  
Julia Bodin ◽  
Noa Horwitz ◽  
Céline Loussert-Fonta ◽  
Adrian Sakr ◽  
...  
Keyword(s):  
Elevated Temperature ◽  
Cellular Level ◽  
Nutrient Fluxes ◽  
Stylophora Pistillata ◽  
Feeding Modes ◽  
Brine Shrimps ◽  
Nutrient Partitioning ◽  
Tight Connection ◽  
C And N ◽  
Lipid Stores

AbstractCorals access inorganic seawater nutrients through their autotrophic endosymbiotic dinoflagellates, but also capture planktonic prey through heterotrophic feeding. Correlating NanoSIMS and TEM imaging, we visualize and quantify the subcellular fate of autotrophic and heterotrophic C and N in the coral Stylophora pistillata using stable isotopes. Six scenarios were compared after 6h: autotrophic pulse (13C-bicarbonate, 15N-nitrate) in either unfed or regularly fed corals, and heterotrophic pulse (13C-, 15N-labelled brine shrimps) in regularly fed corals; each at ambient and elevated temperature. Host assimilation of photosynthates was similar under fed and unfed conditions, but symbionts assimilated 10% more C in fed corals. Photoautotrophic C was primarily channelled into host lipid bodies, whereas heterotrophic C and N were generally co-allocated to the tissue. Food-derived label was detected in some subcellular structures associated with the remobilisation of host lipid stores. While heterotrophic input generally exceeded autotrophic input, it was more negatively affected by elevated temperature. The reduced input from both feeding modes at elevated temperature was accompanied by a shift in the partitioning of C and N, benefiting epidermis and symbiont. This study provides a unique view on the nutrient partitioning in corals and highlights the tight connection of nutrient fluxes in symbiotic partners.

Study on Interface Reactions between Nb-Si System In Situ Composite and Ceramics

2007 ◽  
Vol 546-549 ◽  
pp. 1495-1500
Author(s):  
Jing Jing Yu ◽  
Shu Suo Li ◽  
Ya Fang Han
Keyword(s):  
Elevated Temperature ◽  
Interface Reaction ◽  
Vacuum Arc ◽  
In Situ Composite ◽  
Interface Reactions ◽  
Arc Melting ◽  
Reaction Zones ◽  
C And N ◽  
Face Coat

A Nb-Si system in-situ composite Nb-16Si-24Ti-6Cr-6Al-2Hf(at%) was fabricated using vacuum arc melting method, and then was metallurgically reacted with four kinds of ceramics ZrO2, Y2O3 stabilized ZrO2, Y2O3, SiC+Si3N4 at elevated temperature. The microstructures in the interface reaction zones were investigated by SEM and EDS. The results showed that different extent chemical reactions between the composite and these four kinds of ceramics took place. It has been found that HfO2 riched layer formed near the interfaces between the Nb-Si in-situ composite and three ceramics of ZrO2, Y2O3 stabilized ZrO2 and Y2O3, and thickness of the reaction zones were about 100μm, 10μm, 1μm respectively. C and N elements in SiC+Si3N4 ceramic diffused to the composite at elevated temperature, and a new phase that rich of Ti, C and N elements appeared nearby the interface and accumulated inhomogenously. It may be concluded that the interface reactions of both ZrO2 and SiC+Si3N4 with Nb-Si composite were very violent, therefore they are not suitable as face-coat materials of shell molds for investment casting; the interface reaction of Y2O3 stabilized ZrO2 and Nb-Si composite was slighter than ZrO2 and SiC+Si3N4, and it can be used as face-coat material of shell molds, the interface reaction of Y2O3 and Nb-Si composite was very slight, and is recommended as an ideal face-coat materials of shell molds.

scholarly journals Aeolian nutrient fluxes following wildfire in sagebrush steppe: implications for soil carbon storage

2011 ◽  
Vol 8 (4) ◽  
pp. 8323-8349 ◽  
Author(s):  
N. J. Hasselquist ◽  
M. J. Germino ◽  
J. B. Sankey ◽  
L. J. Ingram ◽  
N. F. Glenn
Keyword(s):  
Biogeochemical Cycling ◽  
Total Carbon ◽  
Sagebrush Steppe ◽  
Nutrient Fluxes ◽  
Aeolian Transport ◽  
Organic C ◽  
Soil C ◽  
N Fluxes ◽  
C And N ◽  
Semi Arid

Abstract. Pulses of aeolian transport following fire can profoundly affect the biogeochemical cycling of nutrients in semi-arid and arid ecosystems. Our objective was to determine horizontal nutrient fluxes during an episodic pulse of aeolian transport that occurred following a wildfire in a semi-arid sagebrush steppe ecosystem in southern Idaho, USA. We also examined how temporal trends in nutrient fluxes were affected by changes in particle sizes of eroded mass as well as nutrient concentrations associated with different particle size classes. In the burned area, total carbon (C) and nitrogen (N) fluxes were as high as 235 g C m−1 d−1 and 19 g N m−1 d−1 during the first few months following fire, whereas C and N fluxes were negligible in an adjacent unburned area throughout the study. Temporal variation in C and N fluxes following fire was largely attributable to the redistribution of saltation-sized particles. Total N and organic C concentrations in the soil surface were significantly lower in the burned relative to the unburned area one year after fire. Our results show how an episodic pulse of aeolian transport following fire can affect the spatial distribution of soil C and N, which, in turn, can have important implications for soil C storage. These findings demonstrate how an ecological disturbance can exacerbate a geomorphic process and highlight the need for further research to better understand the role aeolian transport plays in the biogeochemical cycling of C and N in recently burned landscapes.

scholarly journals Single-Cell Measurements of Fixation and Intercellular Exchange of C and N in the Filaments of the Heterocyst-Forming Cyanobacterium Anabaena sp. Strain PCC 7120

mBio ◽  
2021 ◽  
Author(s):  
Mercedes Nieves-Morión ◽  
Enrique Flores ◽  
Martin J. Whitehouse ◽  
Aurélien Thomen ◽  
Rachel A. Foster
Keyword(s):  
Single Cell ◽  
Cellular Level ◽  
Model Organisms ◽  
Cyanobacterium Anabaena ◽  
Anabaena Sp ◽  
C And N ◽  
Physiological Studies ◽  
Metabolic Activities ◽  
Intercellular Exchange ◽  
Pcc 7120

Filamentous, heterocyst-forming cyanobacteria represent a paradigm of multicellularity in the prokaryotic world. Physiological studies at the cellular level in model organisms are crucial to understand metabolic activities and qualify specific aspects related to multicellularity.

scholarly journals Broad scale proteomic analysis of heat-destabilised symbiosis in the hard coral Acropora millepora

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
K. Petrou ◽  
B. L. Nunn ◽  
M. P. Padula ◽  
D. J. Miller ◽  
D. A. Nielsen
Keyword(s):  
Oxidative Stress ◽  
Elevated Temperature ◽  
Energy Production ◽  
Hard Coral ◽  
Host Proteins ◽  
Acropora Millepora ◽  
Cytoskeletal Regulation ◽  
Lipid Stores ◽  
Broad Scale ◽  
Incremental Increase

AbstractCoral reefs across the globe are threatened by warming oceans. The last few years have seen the worst mass coral bleaching events recorded, with more than one quarter of all reefs irreversibly impacted. Considering the widespread devastation, we need to increase our efforts to understanding the physiological and metabolic shifts underlying the breakdown of this important symbiotic ecosystem. Here, we investigated the proteome (PRIDE accession # PXD011668) of both host and symbionts of the reef-building coral Acropora millepora exposed to ambient (~ 28 °C) and elevated temperature (~ 32 °C for 2 days, following a five-day incremental increase) and explored associated biomolecular changes in the symbiont, with the aim of gaining new insights into the mechanisms underpinning the collapse of the coral symbiosis. We identified 1,230 unique proteins (774 host and 456 symbiont) in the control and thermally stressed corals, of which 107 significantly increased and 125 decreased in abundance under elevated temperature relative to the control. Proteins involved in oxidative stress and proteolysis constituted 29% of the host proteins that increased in abundance, with evidence of impairment to endoplasmic reticulum and cytoskeletal regulation proteins. In the symbiont, we detected a decrease in proteins responsible for photosynthesis and energy production (33% of proteins decreased in abundance), yet minimal signs of oxidative stress or proteolysis. Lipid stores increased > twofold despite reduction in photosynthesis, suggesting reduced translocation of carbon to the host. There were significant changes in proteins related to symbiotic state, including proteins linked to nitrogen metabolism in the host and the V-ATPase (-0.6 fold change) known to control symbiosome acidity. These results highlight key differences in host and symbiont proteomic adjustments under elevated temperature and identify two key proteins directly involved in bilateral nutrient exchange as potential indicators of symbiosis breakdown.

scholarly journals Manganese Benefits Heat-Stressed Corals at the Cellular Level

2021 ◽  
Vol 8 ◽  
Author(s):  
Enrico Montalbetti ◽  
Tom Biscéré ◽  
Christine Ferrier-Pagès ◽  
Fanny Houlbrèque ◽  
Ivan Orlandi ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Coral Bleaching ◽  
Cellular Level ◽  
Stylophora Pistillata ◽  
Cellular Effects ◽  
Previous Hypothesis ◽  
Parallel Pattern ◽  
Prolonged Heat ◽  
The Individual ◽  
Shock Proteins

The intensity and frequency of coral bleaching events have increased worldwide especially due to thermal stress and seawater pollution. Although it has been observed that metal concentration in seawater can affect the coral’s ability to adopt cellular defensive mechanisms to counteract bleaching, more investigations are needed to better understand the role of metals in coral physiology. In this study, we analyzed the individual and combined effects of prolonged heat stress and manganese (Mn) and iron (Fe) enrichments at the cellular level on the coral Stylophora pistillata. Thermal stress caused an up-regulation in the expression of the host Heat shock proteins (Hsps) 60 and 70, which showed a parallel pattern of modulation in all treatments, as well as an increase of lipid peroxidation (LPO) in the holobiont. Fe enrichment did not induce any change in Hsp expression or in the oxidative status of the corals both at the ambient temperature of 26°C or at increased temperature, suggesting that Fe didn’t seem to play a role in mitigating the cellular damages and the coral bleaching. Mn or MnFe enrichment at 26°C seemed to increase the oxidative stress in zooxanthellae, since high LPO and glutathione reductase (GR) levels were recorded, but it did not cause any effect on polyp Hsp expression, probably due to the antioxidant action of GR. With the temperature increase, Mn enrichments prevented any increase in Hsp levels and caused a significant decrease of LPO and GR activity, strengthening a previous hypothesis suggesting that Mn could mitigate the negative cellular effects produced by the thermal stress.

scholarly journals The Effects of Temperature, Light, and Feeding on the Physiology of Pocillopora damicornis, Stylophora pistillata, and Turbinaria reniformis Corals

Water ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2048
Author(s):  
Kerri Dobson ◽  
Christine Ferrier-Pagès ◽  
Casey Saup ◽  
Andréa Grottoli
Keyword(s):  
Elevated Temperature ◽  
Food Sources ◽  
Pocillopora Damicornis ◽  
Metabolic Demand ◽  
Negative Effects ◽  
Low Light ◽  
Stylophora Pistillata ◽  
Light Levels ◽  
Negative Effect ◽  
Species Specific

Evidence has shown that individually feeding or reduced light can mitigate the negative effects of elevated temperature on coral physiology. We aimed to evaluate if simultaneous low light and feeding would mitigate, minimize, or exacerbate negative effects of elevated temperature on coral physiology and carbon budgets. Pocillopora damicornis, Stylophora pistillata, and Turbinaria reniformis were grown for 28 days under a fully factorial experiment including two seawater temperatures (ambient temperature of 25 °C, elevated temperature of 30 °C), two light levels (high light of 300 μmol photons m−2 s−1, low light of 150 μmol photons m−2 s−1), and either fed (Artemia nauplii) or unfed. Coral physiology was significantly affected by temperature in all species, but the way in which low light and feeding altered their physiological responses was species-specific. All three species photo-acclimated to low light by increasing chlorophyll a. Pocillopora damicornis required feeding to meet metabolic demand irrespective of temperature but was unable to maintain calcification under low light when fed. In T. reniformis, low light mitigated the negative effect of elevated temperature on total lipids, while feeding mitigated the negative effects of elevated temperature on metabolic demand. In S. pistillata, low light compounded the negative effects of elevated temperature on metabolic demand, while feeding minimized this negative effect but was not sufficient to provide 100% metabolic demand. Overall, low light and feeding did not act synergistically, nor additively, to mitigate the negative effects of elevated temperature on P. damicornis, S. pistillata, or T. reniformis. However, feeding alone was critical to the maintenance of metabolic demand at elevated temperature, suggesting that sufficient supply of heterotrophic food sources is likely essential for corals during thermal stress (bleaching) events.

scholarly journals Unexpected Diversity of Feeding Modes among Chisel-Mouthed Ethiopian Labeobarbus (Cyprinidae)

Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2345
Author(s):  
Boris A. Levin ◽  
Aleksandra S. Komarova ◽  
Oksana L. Rozanova ◽  
Alexander S. Golubtsov
Keyword(s):  
Adaptive Radiation ◽  
Resource Partitioning ◽  
Piscivorous Fish ◽  
Evolutionary Diversification ◽  
Feeding Modes ◽  
Significant Difference ◽  
Trophic Resource ◽  
C And N ◽  
Using Data ◽  
Protein Rich

Trophic resource partitioning is one of the main drivers of adaptive radiation. The evolutionary diversification of large African barbs, the genus Labeobarbus, seems to be related to mouth polymorphism. The chisel-mouthed or scraping phenotype has repeatedly evolved within Labeobarbus. At least five ecomorphs with a scraping mouth morphology were detected in the waters of the Ethiopian Highlands and can be provisionally classified into two groups: (i) “Varicorhinus”-like, and (ii) “Smiling”-like. Previously, all Labeobarbus with a scraping-mouth morphology were considered to be periphyton feeders. Using data on morphology, diet and stable isotope ratios (C and N), we addressed the question: does a scraping-mouth morphology predict feeding on periphyton? Our study revealed that five scraper ecomorphs exhibited three main feeding modes: (i) periphyton-eating, (ii) herbivory–detritivory, and (iii) insectivory. Two cases of the parallel divergence of sympatric ecomorphs with distinct feeding modes (herbivory–detritivory vs. insectivory) were revealed in two geographically isolated basins. A significant difference in δ15N values was detected among sympatric scraper ecomorphs. A periphytonophagous scraper was rich in δ15N values that are comparable with those in sympatric piscivorous fish. This data sheds light on the possibility of the utilization of periphyton as a protein-rich food by fishes.

scholarly journals Adding insult to injury: Effects of chronic oxybenzone exposure and elevated temperature on two reef-building corals

2019 ◽  
Author(s):  
Tim Wijgerde ◽  
Mike van Ballegooijen ◽  
Reindert Nijland ◽  
Luna van der Loos ◽  
Christiaan Kwadijk ◽  
...  
Keyword(s):  
Global Warming ◽  
Elevated Temperature ◽  
Heat Wave ◽  
Effect Study ◽  
List Type ◽  
Stylophora Pistillata ◽  
Coral Microbiome ◽  
The Face ◽  
Acropora Tenuis ◽  
Coral Health

AbstractWe studied the effect of chronic oxybenzone exposure and elevated temperature on coral health. Microcolonies of Stylophora pistillata and Acropora tenuis were cultured in 20 flow-through aquaria, of which 10 were exposed to oxybenzone at a field-relevant concentration of ~0.06 μg L−1 at 26 °C. After two weeks, half of the corals experienced a heat wave culminating at 33 °C. All S. pistillata colonies survived the heat wave, although heat reduced growth and zooxanthellae density, irrespective of oxybenzone. A. tenuis survival was reduced to 0% at 32 °C, and oxybenzone accelerated mortality. Oxybenzone and heat significantly reduced photosynthetic yield in both species, causing a 5% and 22−33% decrease, respectively. In addition, combined oxybenzone and temperature stress altered the abundance of five bacterial families in the microbiome of S. pistillata. Our results suggest that oxybenzone adds insult to injury by further weakening corals in the face of global warming.Highlights➢Chronic effect study on corals combining oxybenzone and elevated temperature➢Oxybenzone affected photosystem II of coral photosymbionts and altered coral microbiome➢Temperature effects were stronger than oxybenzone effects➢Sensitivities were species-dependent➢Oxybenzone adds insult to injury by weakening corals in the face of global warming

scholarly journals Common reef-building coral in the Northern Red Sea resistant to elevated temperature and acidification

2017 ◽  
Vol 4 (5) ◽  
pp. 170038 ◽  
Author(s):  
Thomas Krueger ◽  
Noa Horwitz ◽  
Julia Bodin ◽  
Maria-Evangelia Giovani ◽  
Stéphane Escrig ◽  
...  
Keyword(s):  
Red Sea ◽  
Elevated Temperatures ◽  
Secondary Ion Mass Spectrometry ◽  
Cellular Level ◽  
Environmental Conservation ◽  
Ice Age ◽  
Gulf Of Aqaba ◽  
Stylophora Pistillata ◽  
Living Well ◽  
National Boundaries

Coral reefs are currently experiencing substantial ecological impoverishment as a result of anthropogenic stressors, and the majority of reefs are facing immediate risk. Increasing ocean surface temperatures induce frequent coral mass bleaching events—the breakdown of the nutritional photo-symbiosis with intracellular algae (genus: Symbiodinium ). Here, we report that Stylophora pistillata from a highly diverse reef in the Gulf of Aqaba showed no signs of bleaching despite spending 1.5 months at 1–2°C above their long-term summer maximum (amounting to 11 degree heating weeks) and a seawater pH of 7.8. Instead, their symbiotic dinoflagellates exhibited improved photochemistry, higher pigmentation and a doubling in net oxygen production, leading to a 51% increase in primary productivity. Nanoscale secondary ion mass spectrometry imaging revealed subtle cellular-level shifts in carbon and nitrogen metabolism under elevated temperatures, but overall host and symbiont biomass proxies were not significantly affected. Now living well below their thermal threshold in the Gulf of Aqaba, these corals have been evolutionarily selected for heat tolerance during their migration through the warm Southern Red Sea after the last ice age. This may allow them to withstand future warming for a longer period of time, provided that successful environmental conservation measures are enacted across national boundaries in the region.

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