Heat activated bleaching

Thermal priming of reef corals can enhance their heat tolerance, however, the legacy effects of heat stress during parental brooding on larval resilience remain understudied. This study investigated whether preconditioning adult coral Pocillopora damicornis to high temperatures (29°C and 32°C) could better prepare their larvae for heat stress. Results showed that heat-acclimated adults brooded larvae with reduced symbiont density and shifted thermal performance curves. Reciprocal transplant experiments demonstrated higher bleaching resistance and better photosynthetic and autotrophic performance in heat-exposed larvae from acclimated adults compared to unacclimated adults...

Marine heatwaves (MHW) are threatening tropical coral reef ecosystems, leading to mass bleaching events worldwide. The combination of heat stress with high irradiance is known to shape the health and redox status of corals, but research is biased toward scleractinian corals, while much less is known on tropical symbiotic soft corals. Here, we evaluated the cellular stress response and the photophysiological performance of the soft coral Sarcophyton cf. glaucum, popularly termed as leather coral, under different global change scenarios...

Exposure to deoxygenation from climate warming and pollution is emerging as a contributing factor of coral bleaching and mortality. However, the combined effects of heating and deoxygenation on bleaching susceptibility remain unknown. Here, we employed short-term thermal stress assays to show that deoxygenated seawater can lower the thermal limit of an Acropora coral by as much as 1 °C or 0.4 °C based on bleaching index scores or dark-acclimated photosynthetic efficiencies, respectively. Using RNA-Seq, we show similar stress responses to heat with and without deoxygenated seawater, both activating putative key genes of the hypoxia-inducible factor response system indicative of cellular hypoxia...

Understanding the distribution and abundance of heat tolerant corals across seascapes is imperative for predicting responses to climate change and to support novel management actions. Thermal tolerance is variable in corals and intrinsic and extrinsic drivers of tolerance are not well understood. Traditional experimental evaluations of coral heat and bleaching tolerance typically involve ramp-and-hold experiments run across days to weeks within aquarium facilities with limits to colony replication. Field-based acute heat stress assays have emerged as an alternative experimental approach to rapidly quantify heat tolerance in many samples yet the role of key methodological considerations on the stress response measured remains unresolved...

The energy consumption in building ventilation, air, and heating conditioning systems, accounts for about 25% of the overall energy consumption in modern society. Therefore, cutting carbon emissions and reducing energy consumption is a growing priority in building construction. Electrochromic devices (ECDs) are considered to be a highly promising energy-saving technology, due to their simple structure, active control, and low energy input characteristics. At present, H+ , OH- and Li+ are the main electrolyte ions used for ECDs...

Xylanases have the potential to be used as bio-deinking and bio-bleaching materials and their application will decrease the consumption of the chlorine-based chemicals currently used for this purpose. However, xylanases with specific properties could act effectively, such as having significant thermostability and alkali resistance, etc. In this study, we found that Tf Xyl10A, a xylanase from Thermobifida fusca , was greatly induced to transcript by microcrystalline cellulose (MCC) substrate. Biochemical characterization showed that Tf Xyl10A is optimally effective at temperature of 80 °C and pH of 9...

Antioxidant aqueous rice straw (RS) extract was obtained by a combined ultrasound-reflux heating process and cellulose fibres (CF) were purified by bleaching the extraction residue. Both fractions were incorporated into corn starch to obtain films by melt blending and compression moulding. CF (at 3 % wt.) greatly increased the elastic modulus (by 200 %) and tensile strength at break (by 100 %) while reducing film stretchability. Films with CF exhibited the greatest barrier capacity to water vapour and oxygen...

Rising ocean temperatures are increasing the rate and intensity of coral mass bleaching events, leading to the collapse of coral reef ecosystems. To better understand the dynamics of coral-algae symbioses, it is critical to decipher the role each partner plays in the holobiont's thermotolerance. Here, we investigated the role of the symbiont by comparing transcriptional heat stress responses of anemones from two thermally distinct locations, Florida (CC7) and Hawaii (H2) as well as a heterologous host-symbiont combination composed of CC7 host anemones inoculated with the symbiont Breviolum minutum (SSB01) from H2 anemones (CC7-B01)...

Fruits from Buglossoides purpurocaerulea (L.) I. M. Johnst. were extracted with methanol through maceration. The phytochemical composition of obtained raw extract was investigated with gas chromatography-mass spectrometry (GC-MS) and high-performance thin layer chromatography (HPTLC) analyses. The total phenolic and flavonoid contents were also quantified and in vitro antioxidant activity was assessed using the DPPH assay and the β-carotene bleaching test. In order to verify the anti-arthritic potential, the raw extract was evaluated for its anti-denaturation effect on heat-treated bovine serum albumin (BSA), chosen as a protein model...

The successful dispersal of coral larvae is vital to the population replenishment and reef recovery and resilience. Despite that this critical early stage is susceptible to ocean warming and acidification, little is known about the responses of coral larvae to warming and acidification across different biological scales. This study explored the influences of elevated temperature (29 °C versus 33 °C) and pCO2 (500 μatm versus 1000 μatm) on brooded larvae of Pocillopora damicornis at the organismal, cellular and gene expression levels...

Spent bleaching clay (SBC) is a problematic waste from the palm oil industry with worldwide availability. In this study, geopolymer was synthesized from SBC, a kind of aluminosilicate material with an alkaline activator solution that is made up of sodium hydroxide and sodium silicate. Calcium silicate (CS), which is a by-product of the silicates removal from wastewater, was also added to the formulation. The geopolymer mixture paste was cured in an oven at 80 °C for 24 h and at room temperature for 7 days...

Coral holobionts are multi-species assemblages, which adds significant complexity to genotype-phenotype connections underlying ecologically important traits like coral bleaching. Small scale heterogeneity in bleaching is ubiquitous in the absence of strong environmental gradients, which provides adaptive variance needed for the long-term persistence of coral reefs. We used RAD-seq, qPCR and LC-MS/MS metabolomics to characterize host genomic variation, symbiont community and biochemical correlates in two bleaching phenotypes of the vertically transmitting coral Montipora capitata...

Marine heatwaves (MHWs) are events of anomalously high sea surface temperatures lasting for five days or more and have recently been linked to widespread environmental stress on marine organisms, though there are few studies in the Beibu Gulf. This study characterizes MHWs near Weizhou Island (21°00'-21°10' N, 109°00'-109°15' E) using a recently developed detection algorithm on a high-resolution satellite sea surface temperature (SST) product and considers their potential influence on coral bleaching events...

In the current study, starch-based active nanocomposite films reinforced with cellulosic nanocrystals (CNCs) of Kudzu were developed as an alternative option to existing biodegradable plastic packaging. Firstly, Kudzu CNCs were prepared by subjecting Kudzu fibers to the processes such as depolymerization followed by bleaching, acid hydrolysis, and mechanical dispersion. Further, nanocomposite films were formulated by blending pearl millet starch (PMS) and glycerol (30%) with different Kudzu CNCs compositions (0-7 wt%) using the solution casting process...

Adsorbable organic halogens (AOX) are often introduced or produced in textile and dyeing processes, such as the chlorination shrink proof process of wool, the bleaching process by sodium hypochlorite and chlorite, the dry-cleaning process by chlorinated solvent, etc. However, part of AOX is difficult to biodegrade and is a persistent bioaccumulative toxic substance with high fat solubility. To promote clean production of textiles and to protect the health of consumers, a conventional method for the detection of AOX in textiles must be established urgently...

Mollusc shells represent excellent systems for the preservation and retrieval of genuine biomolecules from archaeological or palaeontological samples. As a consequence, the post-mortem breakdown of intracrystalline mollusc shell proteins has been extensively investigated, particularly with regard to its potential use as a "molecular clock" for geochronological applications. But despite seventy years of ancient protein research, the fundamental aspects of diagenesis-induced changes to protein structures and sequences remain elusive...

Over the past few decades, extreme events-such as ocean warming, typhoons, and coral bleaching-have been increasing in intensity and frequency, threatening coral reefs from the physiological to ecosystem level. In the present study, the impacts of rising seawater temperatures, typhoons, and coral bleaching events on benthic communities were seasonally assessed over a 21 month-period, using photo-transects at 11 sites in Kenting National Park (KNP), Taiwan. Between August 2015 and April 2017, seven typhoon events were recorded and in situ seawater temperatures in KNP reached a maximum of 31...

This study explored the physiological responses of the coral Pocillopora damicornis to high nitrate concentrations and thermal stresses. The expression of heat shock proteins Hsp60 and Hsp32, Symbiodiniaceae density, Chl a concentration, Fv/Fm, H2 O2 scavenging, and caspase 3 activity varied during 60 h incubations at 28 °C or 32 °C, ambient or high nitrate (~10 μM) concentrations, and their combinations. In combined stresses, corals showed a rapid and high oxidation level negatively affecting the Symbiodiniaceae density and Chl a concentration at 12 h, followed by caspase 3 and Hsps upregulations that induced apoptosis, bleaching and tissue detachment...

Coral reefs face multiple threats, including climate change, agricultural runoff, shipping activities, coastal development, and chemical pollutants. Irgarol 1051, a PSII herbicide, has been used as an antifouling booster since the previously used antibiofouling agent tributyltin (TBT) was banned worldwide. Although the mechanisms through which elevated temperatures cause coral bleaching have been reported, it remains unclear how PSII herbicides cause bleaching. Thus, in this study, we investigated the transcriptomes of Acropora tenuis and its symbiotic dinoflagellates by RNA-sequencing (RNA-Seq) to elucidate the molecular mechanisms underlying Irgarol-induced bleaching...

Reef-building corals rely on intracellular algal symbionts to meet energetic demands. Increasing extreme weather driven by climate change often leads to disruption of this symbiosis and to coral death. Corals can better withstand stress after previous exposure to sublethal conditions, but the mechanisms for this resilience remain unclear. Here, we show that a three-day thermal preconditioning increases tolerance of acute heat stress through modulations in cell death pathways in the stony coral Pocillopora acuta...