scholarly journals Damselfishes alleviate the impacts of sediments on host corals

2020 ◽  
Vol 7 (4) ◽  
pp. 192074 ◽  
Author(s):  
T. J. Chase ◽  
M. S. Pratchett ◽  
M. J. McWilliam ◽  
M. Y. Hein ◽  
S. B. Tebbett ◽  
...  
Keyword(s):  
Critical Role ◽  
High Stress ◽  
Coral Tissue ◽  
Coral Host ◽  
Ecological Communities ◽  
Pocillopora Damicornis ◽  
Mutualistic Relationship ◽  
Aquarium Experiment ◽  
Pomacentrus Moluccensis ◽  
Facilitative Interactions

Mutualisms play a critical role in ecological communities; however, the importance and prevalence of mutualistic associations can be modified by external stressors. On coral reefs, elevated sediment deposition can be a major stressor reducing the health of corals and reef resilience. Here, we investigated the influence of severe sedimentation on the mutualistic relationship between small damselfishes ( Pomacentrus moluccensis and Dascyllus aruanus ) and their coral host ( Pocillopora damicornis ). In an aquarium experiment, corals were exposed to sedimentation rates of approximately 100 mg cm −2 d −1 , with and without fishes present, to test whether: (i) fishes influence the accumulation of sediments on coral hosts, and (ii) fishes moderate partial colony mortality and/or coral tissue condition. Colonies with fishes accumulated much less sediment compared with colonies without fishes, and this effect was strongest for colonies with D. aruanus (fivefold less sediment than controls) as opposed to P. moluccensis (twofold less sediment than controls). Colonies with symbiont fishes also had up to 10-fold less sediment-induced partial mortality, as well as higher chlorophyll and protein concentrations. These results demonstrate that fish mutualisms vary in the strength of their benefits, and indicate that some mutualistic or facilitative interactions might become more important for species health and resilience at high-stress levels.

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 Highly Dynamic Cellular-Level Response of Symbiotic Coral to a Sudden Increase in Environmental Nitrogen

mBio ◽  
2013 ◽  
Vol 4 (3) ◽  
Author(s):  
C. Kopp ◽  
M. Pernice ◽  
I. Domart-Coulon ◽  
C. Djediat ◽  
J. E. Spangenberg ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Nitrogen Availability ◽  
Secondary Ion Mass Spectrometry ◽  
Coral Tissue ◽  
Coral Host ◽  
Sudden Increase ◽  
Pocillopora Damicornis ◽  
Nitrogenous Compounds ◽  
Ion Mass Spectrometry ◽  
Secondary Ion

ABSTRACT Metabolic interactions with endosymbiotic photosynthetic dinoflagellate Symbiodinium spp. are fundamental to reef-building corals (Scleractinia) thriving in nutrient-poor tropical seas. Yet, detailed understanding at the single-cell level of nutrient assimilation, translocation, and utilization within this fundamental symbiosis is lacking. Using pulse-chase 15N labeling and quantitative ion microprobe isotopic imaging (NanoSIMS; nanoscale secondary-ion mass spectrometry), we visualized these dynamic processes in tissues of the symbiotic coral Pocillopora damicornis at the subcellular level. Assimilation of ammonium, nitrate, and aspartic acid resulted in rapid incorporation of nitrogen into uric acid crystals (after ~45 min), forming temporary N storage sites within the dinoflagellate endosymbionts. Subsequent intracellular remobilization of this metabolite was accompanied by translocation of nitrogenous compounds to the coral host, starting at ~6 h. Within the coral tissue, nitrogen is utilized in specific cellular compartments in all four epithelia, including mucus chambers, Golgi bodies, and vesicles in calicoblastic cells. Our study shows how nitrogen-limited symbiotic corals take advantage of sudden changes in nitrogen availability; this opens new perspectives for functional studies of nutrient storage and remobilization in microbial symbioses in changing reef environments. IMPORTANCE The methodology applied, combining transmission electron microscopy with nanoscale secondary-ion mass spectrometry (NanoSIMS) imaging of coral tissue labeled with stable isotope tracers, allows quantification and submicrometric localization of metabolic fluxes in an intact symbiosis. This study opens the way for investigations of physiological adaptations of symbiotic systems to nutrient availability and for increasing knowledge of global nitrogen and carbon biogeochemical cycling.

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 Microscale tracking of coral disease reveals timeline of infection and heterogeneity of polyp fate

2018 ◽  
Author(s):  
Assaf R. Gavish ◽  
Orr H. Shapiro ◽  
Esti Kramarsky-Winter ◽  
Assaf Vardi
Keyword(s):  
Disease Progression ◽  
Defense Mechanism ◽  
Coral Disease ◽  
Coral Host ◽  
Pocillopora Damicornis ◽  
Spatial And Temporal Scales ◽  
Infection Dynamics ◽  
Key Steps ◽  
Coral Pathogen ◽  
Gastrovascular System

AbstractCoral disease is often studied at scales ranging from single colonies to the entire reef. This is particularly true for studies following disease progression through time. To gain a mechanistic understanding of key steps underlying infection dynamics, it is necessary to study disease progression, and host-pathogen interactions, at relevant microbial scales. Here we provide a dynamic view of the interaction between the model coral pathogen Vibrio coralliilyticus and its coral host Pocillopora damicornis at unprecedented spatial and temporal scales. This view is achieved using a novel microfluidics-based system specifically designed to allow microscopic study of coral infection in-vivo under controlled environmental conditions. Analysis of exudates continuously collected at the system’s outflow, allows a detailed biochemical and microbial analyses coupled to the microscopic observations of the disease progression. The resulting multilayered dataset provides the most detailed description of a coral infection to-date, revealing distinct pathogenic processes as well as the defensive behavior of the coral host. We provide evidence that infection in this system occurs following ingestion of the pathogen, and may then progress through the gastrovascular system. We further show infection may spread when pathogens colonize lesions in the host tissue. Copious spewing of pathogen-laden mucus from the polyp mouths results in effective expulsion of the pathogen from the gastrovascular system, possibly serving as a first line of defense. A secondary defense mechanism entails the severing of calicoblastic connective tissues resulting in the controlled isolation of diseased polyps, or the survival of individual polyps within infected colonies. Further investigations of coral-pathogen interactions at these scales will help to elucidate the complex interactions underlying coral disease, as we as the versatile adaptive response of the coral ecosystems to fluctuating environments.

scholarly journals Measuring light scattering and absorption in corals with Inverse Spectroscopic Optical Coherence Tomography (ISOCT): a new tool for non-invasive monitoring

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
G. L. C. Spicer ◽  
A. Eid ◽  
D. Wangpraseurt ◽  
T. D. Swain ◽  
J. A. Winkelmann ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Optical Properties ◽  
Light Scattering ◽  
Light Propagation ◽  
Coral Tissue ◽  
Coral Host ◽  
Invasive Monitoring ◽  
Optical Coherence ◽  
Invasive Approach ◽  
Non Invasive

Abstract The success of reef-building corals for >200 million years has been dependent on the mutualistic interaction between the coral host and its photosynthetic endosymbiont dinoflagellates (family Symbiodiniaceae) that supply the coral host with nutrients and energy for growth and calcification. While multiple light scattering in coral tissue and skeleton significantly enhance the light microenvironment for Symbiodiniaceae, the mechanisms of light propagation in tissue and skeleton remain largely unknown due to a lack of technologies to measure the intrinsic optical properties of both compartments in live corals. Here we introduce ISOCT (inverse spectroscopic optical coherence tomography), a non-invasive approach to measure optical properties and three-dimensional morphology of living corals at micron- and nano-length scales, respectively, which are involved in the control of light propagation. ISOCT enables measurements of optical properties in the visible range and thus allows for characterization of the density of light harvesting pigments in coral. We used ISOCT to characterize the optical scattering coefficient (μs) of the coral skeleton and chlorophyll a concentration of live coral tissue. ISOCT further characterized the overall micro- and nano-morphology of live tissue by measuring differences in the sub-micron spatial mass density distribution (D) that vary throughout the tissue and skeleton and give rise to light scattering, and this enabled estimates of the spatial directionality of light scattering, i.e., the anisotropy coefficient, g. Thus, ISOCT enables imaging of coral nanoscale structures and allows for quantifying light scattering and pigment absorption in live corals. ISOCT could thus be developed into an important tool for rapid, non-invasive monitoring of coral health, growth and photophysiology with unprecedented spatial resolution.

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 Sessile bacterium unlocks ability of surface motility through mutualistic interspecies interaction

2020 ◽  
Author(s):  
Miaoxiao Wang ◽  
Shuang Geng ◽  
Bing Hu ◽  
Yong Nie ◽  
Xiao-Lei Wu
Keyword(s):  
Critical Role ◽  
Large Body ◽  
Selective Advantage ◽  
Food Sources ◽  
Natural Environments ◽  
Interspecies Interaction ◽  
Interaction Mode ◽  
Mutualistic Relationship ◽  
Surface Motility ◽  
Motile Bacteria

AbstractIn addition to their common planktonic lifestyle, bacteria frequently live in surface-associated habitats. Surface motility is essential for exploring these habitats for food sources. However, many bacteria are found on surfaces, even though they lack features required for migrating along surfaces. How these canonical non-motile bacteria adapt to the environmental fluctuations on surfaces remains unknown. Recently, several cases of interspecies interaction were reported that induce surface motility of non-motile bacteria either by using ‘hitchhiking’ strategies or through ‘social spreading’ mechanisms. Here, we report a previously unknown mechanism for interaction-dependent surface motility of the canonical non-motile bacterium, Dietzia sp. DQ12-45-1b, which is induced by interaction with a dimorphic prosthecate bacterium, Glycocaulis alkaliphilus 6B-8T. Dietzia cells exhibits “sliding”-like motility in an area where the strain Glycocaulis cells was pre-colonized with a sufficient density. Furthermore, we show that biosurfactants play a critical role in inducing the surface motility of Dietzia cells. Our analysis also demonstrates that Dietzia degrade n-alkanes and provide Glycocaulis with the resulting metabolites for survival, which in turn enabled directional migration of Dietzia towards nutrients in the environment. Such interaction-dependent migration was also found between Dietzia and Glycocaulis strains isolated from other habitats, suggesting that this mutualistic relationship ubiquitously occurs in natural environments. In conclusion, we propose a novel model for such a ‘win-win’ strategy, whereby non-motile bacteria pay metabolites to dimorphic prosthecate bacteria in return for migrating to reach environments otherwise inaccessible. We propose that this mechanism represents a common strategy for canonically non-motile bacteria living on a surface.ImportanceCell motility provides a selective advantage for bacteria searching for nutrients. While a large body of evidence exists for how motile bacteria migrate on surface by virtue of different ways of motility, fewer studies concerned about how canonical non-motile bacteria adapted to those surface-associated habitats. Recent reports have proposed that interactions with other bacteria trigger the movement of those sessile bacteria. However, these interactions are limited to ‘hitchhiking’ or ‘social spreading’ modes. Here, we characterized a previously unknown interaction mode between Dietzia and Glycocaulis.This interaction differs from previously described modes, thus advance our limited understanding of how sessile bacteria move on surfaces. We propose that this interaction mode represents a ‘win-win’ strategy for both strains, and this mode might be widely distributed across diverse environments. These novel insights should greatly assist in understanding the mechanisms responsible for the cellular interplay between microbes in complex microbiomes.

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.

scholarly journals Long-Term Modelling Reveals Contrasting Population Trends Among North American Hummingbirds

2021 ◽  
Author(s):  
Simon G. English ◽  
Christine A. Bishop ◽  
Scott Wilson ◽  
Adam C. Smith
Keyword(s):  
North America ◽  
North American ◽  
Conservation Status ◽  
Critical Role ◽  
Population Trends ◽  
Ecological Communities ◽  
Breeding Bird ◽  
Past Half Century ◽  
Rate Of Decline

Abstract As pollinators, hummingbirds play a critical role for both the function of ecological communities and in providing ecosystem services for people. Throughout North America, this diverse family of birds is experiencing impacts of transformations to their habitat. To examine the conservation status of North American hummingbirds, we analyzed Breeding Bird Survey data for 8 species and 3 genera from 1970 to 2019 (long-term) and from 2009 to 2019 (short-term, approximately three generations). Among the Selasphorus genus, Allen’s, rufous, and broad-tailed hummingbirds have declined since 1970, and the rate of decline increased from 2009 to 2019. In a reversal of the trends from the past half-century, ruby-throated hummingbirds of Eastern North America have declined since approximately 2004 throughout most of the species range. In contrast, Anna’s hummingbird populations have increased dramatically since 1970 in their range in western North America. This increase is most exaggerated in Canada, related to a northern range expansion. Our results highlight contrasting population trends across species and provide an important first step to address declines, most notably among species in the Selasphorus and Archilochus genera. Our geographic modelling also emphasizes the need to prioritize regions of conservation interest in the breeding and wintering ranges of hummingbirds.

scholarly journals Colorimetric Detection of Caspase 3 Activity and Reactive Oxygen Derivatives: Potential Early Indicators of Thermal Stress in Corals

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Mickael Ros ◽  
Mathieu Pernice ◽  
Sebastien Le Guillou ◽  
Martina A. Doblin ◽  
Verena Schrameyer ◽  
...  
Keyword(s):  
Caspase 3 ◽  
Colorimetric Detection ◽  
Photochemical Efficiency ◽  
Reactive Oxygen ◽  
Coastal Development ◽  
Clinical Approach ◽  
Coral Host ◽  
Pocillopora Damicornis ◽  
Coral Health ◽  
Early Indicators

There is an urgent need to develop and implement rapid assessments of coral health to allow effective adaptive management in response to coastal development and global change. There is now increasing evidence that activation of caspase-dependent apoptosis plays a key role during coral bleaching and subsequent mortality. In this study, a “clinical” approach was used to assess coral health by measuring the activity of caspase 3 using a commercial kit. This method was first applied while inducing thermal bleaching in two coral species,Acropora milleporaandPocillopora damicornis. The latter species was then chosen to undergo further studies combining the detection of oxidative stress-related compounds (catalase activity and glutathione concentrations) as well as caspase activity during both stress and recovery phases. Zooxanthellae photosystem II (PSII) efficiency and cell density were measured in parallel to assess symbiont health. Our results demonstrate that the increased caspase 3 activity in the coral host could be detected before observing any significant decrease in the photochemical efficiency of PSII in the algal symbionts and/or their expulsion from the host. This study highlights the potential of host caspase 3 and reactive oxygen species scavenging activities as early indicators of stress in individual coral colonies.

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