scholarly journals Molecular characterization reveals the complexity of previously overlooked coral-exosymbiont interactions and the implications for coral-guild ecology

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
H. Rouzé ◽  
M. Leray ◽  
H. Magalon ◽  
L. Penin ◽  
P. Gélin ◽  
...  
Keyword(s):  
Coral Reefs ◽  
Environmental Conditions ◽  
New Caledonia ◽  
Coral Host ◽  
Cryptic Diversity ◽  
Pocillopora Damicornis ◽  
Ecological Studies ◽  
Functional Roles ◽  
Associated Species ◽  
Interaction Webs

Abstract Several obligate associate crabs and shrimps species may co-occur and interact within a single coral host, leading to patterns of associations that can provide essential ecological services. However, knowledge of the dynamics of interactions in this system is limited, partly because identifying species involved in the network remains challenging. In this study, we assessed the diversity of the decapods involved in exosymbiotic assemblages for juvenile and adult Pocillopora damicornis types α and β on reefs of New Caledonia and Reunion Island. This approach revealed complex patterns of association at regional and local scales with a prevalence of assemblages involving crab-shrimp partnerships. Furthermore, the distinction of two lineages in the snapping shrimp Alpheus lottini complex, rarely recognized in ecological studies, reveals a key role for cryptic diversity in structuring communities of mutualists. The existence of partnerships between species that occurred more commonly than expected by chance suggests an increased advantage for the host or a better adaptation of associated species to local environmental conditions. The consideration of cryptic diversity helps to accurately describe the complexity of interaction webs for diverse systems such as coral reefs, as well as the functional roles of dominant associated species for the persistence of coral populations.

scholarly journals The Bouraké semi-enclosed lagoon (New Caledonia). A natural laboratory to study the life-long adaptation of a coral reef ecosystem to climate change-like conditions

2021 ◽  
Author(s):  
Federica Maggioni ◽  
Mireille Pujo-Pay ◽  
Jérome Aucan ◽  
Carlo Cerrano ◽  
Barbara Calcinai ◽  
...  
Keyword(s):  
Climate Change ◽  
Coral Reefs ◽  
Dissolved Oxygen ◽  
Environmental Conditions ◽  
New Caledonia ◽  
Future Climate Change ◽  
Chemical Parameters ◽  
The Future ◽  
Natural Laboratory ◽  
Reef Ecosystem

Abstract. According to current experimental evidence, coral reefs could disappear within the century if CO2 emissions remain unabated. However, recent discoveries of diverse and high cover reefs that already thrive under extreme conditions seem to contradict these projections. Volcanic CO2 vents, semi-enclosed lagoons and mangrove estuaries are unique study sites where one or more ecologically relevant parameters for life in the oceans are close or even worse than currently projected for the year 2100. These natural analogues of future conditions hold new hope for the future of coral reefs and provide unique natural laboratories to explore how reef species could keep pace with climate change. To achieve this, it is essential to characterize their environment as a whole, and accurately consider all possible environmental factors that may differ from what is expected in the future and that may possibly alter the ecosystem response. In this study, we focus on the semi-enclosed lagoon of Bouraké (New Caledonia, SW Pacific Ocean) where a healthy reef ecosystem thrives in warm, acidified and deoxygenated water. We used a multi-scale approach to characterize the main physical-chemical parameters and mapped the benthic community composition (i.e., corals, sponges, and macroalgae). The data revealed that most physical and chemical parameters are regulated by the tide, strongly fluctuate 3 to 4 times a day, and are entirely predictable. The seawater pH and dissolved oxygen decrease during falling tide and reach extreme low values at low tide (7.2 pHT and 1.9 mg O2 L−1 at Bouraké, vs 7.9 pHT and 5.5 mg O2 L−1 at reference reefs). Dissolved oxygen, temperature, and pH fluctuates according to the tide of up to 4.91 mg O2 L−1, 6.50 °C, and 0.69 pHT units on a single day. Furthermore, the concentration of most of the chemical parameters was one- to 5-times higher at the Bouraké lagoon, particularly for organic and inorganic carbon and nitrogen, but also for some nutrients, notably silicates. Surprisingly, despite extreme environmental conditions and altered seawater chemical composition, our results reveal a diverse and high cover community of macroalgae, sponges and corals accounting for 28, 11 and 66 species, respectively. Both environmental variability and nutrient imbalance might contribute to their survival under such extreme environmental conditions. We describe the natural dynamics of the Bouraké ecosystem and its relevance as a natural laboratory to investigate the benthic organism’s adaptive responses to multiple stressors like future climate change conditions.

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 The mushroom coral as a habitat

2011 ◽  
Vol 92 (4) ◽  
pp. 647-663 ◽  
Author(s):  
Bert W. Hoeksema ◽  
Sancia E.T. Van der Meij ◽  
Charles H.J.M. Fransen
Keyword(s):  
Coral Species ◽  
Marine Biodiversity ◽  
Coral Host ◽  
Associated Fauna ◽  
Reef Corals ◽  
Symbiotic Relationships ◽  
Mushroom Coral ◽  
Endosymbiotic Algae ◽  
Associated Species ◽  
Shallow Seas

The evolution of symbiotic relationships involving reef corals has had much impact on tropical marine biodiversity. Because of their endosymbiotic algae (zooxanthellae) corals can grow fast in tropical shallow seas where they form reefs that supply food, substrate and shelter for other organisms. Many coral symbionts are host-specific, depending on particular coral species for their existence. Some of these animals have become popular objects for underwater photographers and aquarists, whereas others are hardly noticed or considered pests. Loss of a single coral host species also leads to the disappearance of some of its associated fauna. In the present study we show which mushroom corals (Scleractinia: Fungiidae) are known to act as hosts for other organisms, such as acoel flatworms, copepods, barnacles, gall crabs, pontoniine shrimps, mytilid bivalves, epitoniid snails, coralliophilid snails, fish and certain types of zooxanthellae. Several of these associated organisms appear to be host-specific whereas other species are generalists and not even necessarily restricted to fungiid hosts.Heliofungia actiniformisis one of the most hospitable coral species known with a recorded associated fauna consisting of at least 23 species. The availability of a phylogeny reconstruction of the Fungiidae enables comparisons of closely related species of mushroom corals regarding their associated fauna. Application of a phylogenetic ecological analysis indicates that the presence or absence of associated organisms is evolutionarily derived or habitat-induced. Some associations appear to be restricted to certain evolutionary lineages within the Fungiidae, whereas the absence of associated species may be determined by ecomorphological traits of the host corals, such as coral dimensions (coral diameter and thickness) and polyp shape (tentacle size).

Oceanic δ13C, environmental changes and Carboniferous coral reef development: Records from Tianlin and Ziyun (southern China)

2020 ◽  
Author(s):  
Marine Maillet ◽  
Elias Samankassou
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Environmental Conditions ◽  
Environmental Changes ◽  
Southern China ◽  
Ocean Current ◽  
Late Devonian ◽  
Equatorial Position ◽  
Eastern Australia ◽  
Devonian Extinction

<p>Metazoan reef builders receded globally during the Carboniferous, after the Late Devonian extinction event, with only few exceptions of coral-bearing bioconstructions reported worldwide. Among the latter, two exceptional extended coral reefs, dated as Late Viséan–Serpukhovian and Kasimovian-Gzhelian in age, respectively, were recently reported from southern China. The scarcity of coral buildups worldwide suggests global unfavorable conditions, with specific settings considered to represent refugia. To constrain these environmental conditions, seawater composition is reconstructed using carbon and oxygen isotopes originating from five measured sections located in southern China.</p><p>The resulting δ<sup>13</sup>C data reveals several environmental changes throughout the Carboniferous attributed to climate changes, ocean current variations, and proliferation of terrestrial plants. During the Late Viséan-earliest Serpukhovian, the high δ<sup>13</sup>C values (<sub>˜</sub>3‰) are interpreted as recording short-lived glacial events, with the expansion of ice-sheets in South America and eastern Australia. The scarcity of coral reef growth suggests that the cooling acted as an inhibiting factor during this period. Conversely, the development of the exceptional coral reefs in southern China could be explained by the persistence of warm oceanic currents in the epicontinental sea, located in equatorial position. During the Kasimovian-Gzhelian, the gradual δ<sup>13</sup>C positive shift from -0.7 to +4.7‰ coincides with a short-lived warming, which should be suitable for the recovery of coral communities. However, in spite of the mild climate, the scarcity of Pennsylvanian coral reef leads to consider other inhibiting factors (e.g. biological competition and aragonite seas). Interestingly, the disappearance of coral reefs in southern China correlates with negative δ<sup>13</sup>C shifts (e.g. Mid-Viséan, Late Gzhelian), interpreted as related to intensified upwellings.</p><p>The reconstitution of the Carboniferous environmental conditions documents several factors contributing to the metazoan reef demise and recovery subsequent to the Late Devonian extinction events, and adds to our current knowledge of the longest reef recovery in the Phanerozoic.</p><p> </p><p> </p>

scholarly journals Hidden in plain view: Cryptic diversity in the emblematic Araucaria of New Caledonia

2016 ◽  
Vol 103 (5) ◽  
pp. 888-898 ◽  
Author(s):  
Markus Ruhsam ◽  
Alexandra Clark ◽  
Aline Finger ◽  
Adrien S. Wulff ◽  
Robert R. Mill ◽  
...  
Keyword(s):  
New Caledonia ◽  
Cryptic Diversity

scholarly journals Diversity of trypanorhynch metacestodes in teleost fishes from coral reefs off eastern Australia and New Caledonia

Parasite ◽  
2014 ◽  
Vol 21 ◽  
pp. 60 ◽  
Author(s):  
Ian Beveridge ◽  
Rodney A. Bray ◽  
Thomas H. Cribb ◽  
Jean-Lou Justine
Keyword(s):  
Coral Reefs ◽  
New Caledonia ◽  
Teleost Fishes ◽  
Eastern Australia

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 The loss of foundation species revisited

2015 ◽  
Author(s):  
Allyson Degrassi ◽  
Steven T Brantley ◽  
Carrie R. Levine ◽  
Robert Miller ◽  
Jacqueline Mohan ◽  
...  
Keyword(s):  
Citation Analysis ◽  
Species Concept ◽  
Abundant Species ◽  
Local Scale ◽  
Foundation Species ◽  
Functional Roles ◽  
Analysis And Synthesis ◽  
Regional Abundance ◽  
Definition Of ◽  
Associated Species

Ecologists and environmental scientists often prioritize research efforts with conservation importance. Dominant, widespread, or locally abundant species at low risk of extinction receive relatively little attention unless they are invasive. Native foundation species create habitats and environmental conditions that support many associated species and modulate local-scale ecosystem processes, but the generally high local or regional abundance of foundation species may lead to less research about them. We used citation analysis (2005-2014) to examine research following from a suggestion to identify and study foundation species while they were still common and not threatened. We explored the use and expanding definition of the foundation species concept, as well as the trajectory and ecological focus of research on foundation species throughout the world in 378 papers published in this nine-year span. Contemporary authors who cite key papers defining a foundation species pay little attention to its actual definition and species studied in this context rarely were identified as foundation species. Although functions and roles of foundation species, such as creating unique microclimates or supporting dependent species, are being studied, less research is focused on identifying them before they are threatened or lost from the ecosystem that they otherwise define. Invasive species were identified as the most common threat to foundation species. Our citation analysis and synthesis provides a new conceptual framework linking identification of and research about foundation species with their functional roles and our ability to manage emerging threats to them.

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