Coral Ecology Research Articles

Settlement ecology of scleractinian corals of the Northeastern Tropical Pacific

Reproduction and recruitment are essential processes for the continued success of coral communities. Islas Marias Archipelago is considered a connectivity node among coral communities distributed along the Northeastern Tropical Pacific (NTP); as such, sexual reproduction of scleractinian corals affects the maintenance of the local populations and the long-distance connectivity of reefs across the region. In this study, successful sexual reproduction in the species of the three most abundant scleractinian corals genera was demonstrated, in part by documenting gamete presence and maturation in tissues and spatio-temporal variability in juvenile coral settlement, which were quantified across substrate type, habitat quality, and environmental factors. Only 12 larvae recruited (ten Porites, two Pavona) to artificial substrates, and monthly recruitment density of 1.82 ± 0.23 recruits m−2 (n = 383) was recorded on natural substrates. There were significant differences between genera, with Porites producing the highest density of recruits (0.60 ± 0.45 recruits m−2, followed by Pavona (0.52 ± 0.24 recruits m−2) and Pocillopora (0.28 ± 0.06 recruits m−2). The highest coral recruitment was observed at Baby Reef (2.57 ± 0.46 recruits m−2), followed by Cleofas II (1.81 ± 0.21 recruits m−2) and Japanese Garden (1.24 ± 0.46 recruits m−2); the former site was characterized by the highest cover of crustose coralline algae. We found successful recruitment of the main reef-forming species in the Mexican Pacific and suggest that Islas Marias is a region of critical importance in terms of its function as a source of genetic variability, and, the generation of, new individuals that will be key to sustaining coral reef ecosystems in the NTP.

Assessment of the Economic Value of Ecological Conservation of the Kenting Coral Reef

Sightseeing and recreation have become prevalent in the Kenting coral reef area. However, coral reefs in Kenting are being severely bleached at an increasing rate under the influence of excessive human activities and climate change that have necessitated stronger conservation policies by the government. Based on a random utility model for coral ecology conservation, the preferences and willingness-to-pay (WTP) values of diving, fishing, and sightseeing visitors are analyzed. Empirical results show that: (1) increasing living coral coverage, improving water quality, restricting the number of daily visitors, increasing biodiversity, increasing the ratio of marine protected areas, and reducing the coral reef’s conservation fund will improve the overall utility of Kenting for visitors; (2) the WTP values significantly vary with respondents’ socioeconomic background and travel behaviors; (3) the results of a latent class model (LCM) also show that the two groups with different coral conservation preferences and WTP values have different socioeconomic backgrounds and travel behaviors.

Red Sea corals under Artificial Light Pollution at Night (ALAN) undergo oxidative stress and photosynthetic impairment.

Coral reefs represent the most diverse marine ecosystem on the planet, yet they are undergoing an unprecedented decline due to a combination of increasing global and local stressors. Despite the wealth of research investigating these stressors, Artificial Light Pollution at Night (ALAN) or “ecological light pollution” represents an emerging threat that has received little attention in the context of coral reefs, despite the potential of disrupting the chronobiology, physiology, behavior, and other biological processes of coral reef organisms. Scleractinian corals, the framework builders of coral reefs, depend on lunar illumination cues to synchronize their biological rhythms such as behavior, reproduction and physiology. While, light pollution (POL) may mask and lead de‐synchronization of these biological rhythms process. To reveal if ALAN impacts coral physiology, we have studied two coral species, Acropora eurystoma and Pocillopora damicornis, from the Gulf of Eilat/Aqaba, Red Sea, which is undergoing urban development that has led to severe POL at night. Our two experimental design data revealed that corals exposed to ALAN face an oxidative stress condition, show lower photosynthesis performances measured by electron transport rate (ETR), as well as changes in chlorophyll and algae density parameters. Testing different lights such as Blue LED and White LED spectrum showed more extreme impact in comparison to Yellow LEDs on coral physiology. The finding of this work sheds light on the emerging threat of POL and the impacts on the biology and ecology of Scleractinian corals, and will help to formulate specific management implementations to mitigate its potentially harmful impacts.

3D HABITAT COMPLEXITY OF CORAL REEFS IN THE NORTHWESTERN HAWAIIAN ISLANDS IS DRIVEN BY CORAL ASSEMBLAGE STRUCTURE

Abstract. Corals act as ecosystem engineers by secreting structurally complex calcium carbonate skeletons on the benthic substrate that provide habitat for a diverse array of associated reef organisms. Communities of living corals create large and dynamic benthic structures that directly affect ecological parameters such as habitat provisioning and light availability, thus influencing overall ecosystem function. Despite the important role 3D structural complexity plays in ecosystem biodiversity and productivity, the field of coral ecology has lacked accessibility to practical technology capable of quantifying 3D characteristics of underwater habitats. Advancements in the field of computer vision has led to Structure-from-Motion (SfM) photogrammetry, which provides a simple and cost-effective method for creating high-resolution and spatially accurate 3D reconstructions of natural environments. Integrating SfM approaches into coral reef research and monitoring has provided useful insight into the relationship between 3D habitat complexity and ecological processes. In this study, we examined the relationships among 2D estimates of live coral cover and several metrics of 3D habitat structural complexity among eleven long-term monitoring sites at French Frigate Shoals. Our findings show that coral assemblage structure acts as a significant driver of 3D structural complexity of coral reef habitats at this atoll. This study highlights the importance of diverse and abundant coral assemblages in supporting structurally complex coral reef habitats and provides a framework for future investigations into the ecological role of various coral morphotypes.

The Diversity and Ecological Role of Non-scleractinian Corals (Antipatharia and Alcyonacea) on Scleractinian Cold-Water Coral Mounds

Cold-water coral carbonate mounds, created by framework-building scleractinian corals, are also important habitats for non-scleractinian corals, whose ecology and role are understudied in deep-sea environments. This paper describes the diversity, ecology and role of non-scleractinian corals on scleractinian cold-water coral carbonate mounds in the Logachev Mound Province, Rockall Bank, NE Atlantic. In total ten non-scleractinian species were identified, which were mapped out along eight ROV video transects. Eight species were identified as black corals (three belonging to the family Schizopathidae, one each to the Leiopathidae, Cladopathidae, and Antipathidae and two to an unknown family) and two as gorgonians (Isididae and Plexauridae). The most abundant species were Leiopathes sp. and Parantipathes sp. 2. Areas with a high diversity of non-scleractinian corals are interpreted to offer sufficient food, weak inter-species competition and the presence of heterogeneous and hard settlement substrates. A difference in the density and occurrence of small vs. large colonies of Leiopathes sp. was also observed, which is likely related to a difference in the stability of the substrate they choose for settlement. Non-scleractinian corals, especially black corals, are an important habitat for crabs, crinoids, and shrimps in the Logachev Mound Province. The carrier crab Paromola sp. was observed carrying the plexaurid Paramuricea sp. and a black coral species belonging to the genus Parantipathes, a behavior believed to provide the crab with camouflage or potentially a defense mechanism against predators. More information on the ecophysiology of non-scleractinian corals and fine-scale local organic matter supply are needed to understand what drives differences in their spatial distribution and community structure.

Upwelling as the major source of nitrogen for shallow and deep reef‐building corals across an oceanic atoll system

AbstractOceanographic processes shape coral reefs worldwide by redistributing inorganic nutrients and particulate resources over depth. Deep‐water upwelling occurs frequently in coral reef ecosystems, but its impact on coral nutrition remains unclear.This study investigated the influence of upwelling on the trophic ecology of three common reef‐building corals (Galaxea fascicularis,Pachyseris speciosaandPocillopora verrucosa) from different reef depths (shallow reef, 10 m, vs. deep reef, 30 m) and reef exposures (oceanic rim vs. Inner Sea) across > 250 km of the Maldives archipelago, Indian Ocean. Carbon and nitrogen stable isotope ratios (δ13C and δ15N) of coral hosts, their symbionts and particulate organic matter (POM) were used to characterize coral trophic strategies.Across the Maldives, consistent mean δ15N values were recorded in hosts (5.5‰) and symbionts (5.2‰) of the three coral species from shallow and deep reefs of oceanic and Inner Sea reef exposures. Coral hosts, symbionts and POM from both depths had δ15N values that were consistent with the isotopic signature of a deep‐water nitrate source transported to surface waters via upwelling.In contrast, a wide range of δ13C values (~10‰) revealed different trophic strategies and isotopic niches among the coral species. Different mean δ13C values ofG. fascicularisindicated greater symbiont autotrophy in corals from shallow (‐15.5‰) compared to deep reefs (‐17.6‰). Conversely, the mean δ13C values ofP. speciosa(‐15.1‰) andP. verrucosa(‐17.7‰) were not affected by reef depth. These corals maintained consistent trophic strategies over depth, withP. speciosarelying more on autotrophy compared toP. verrucosa.Despite different reef exposure to oceanic waters, coral host and POM δ15N and δ13C values did not differ between oceanic and Inner Sea reef exposures. Nutritional resources appear to be homogenous in the central Maldives due to atoll‐wide water circulation. However, species‐specific trophic strategies resulted in diverse patterns of δ13C values over depth. Because heterotrophic feeding has been linked to coral host survival through coral bleaching events, understanding the trophic ecology of corals within the reef assemblage can provide insight into species resilience under ocean warming conditions. As a member of the typically competitive Pocilloporidae family, the dependence ofP. verrucosaon heterotrophy may help this coral be a future “winner” under sustained ocean warming.Aplain language summaryis available for this article.

Paleobiological Traits That Determined Scleractinian Coral Survival and Proliferation During the Late Paleocene and Early Eocene Hyperthermals

AbstractCoral reefs are particularly sensitive to environmental disturbances, such as rapid shifts in temperature or carbonate saturation. Work on modern reefs has suggested that some corals will fare better than others in times of stress and that their life history traits might correlate with species survival. These same traits can be applied to fossil taxa to assess whether life history traits correspond with coral survival through past intervals of stress similar to future climate predictions. This study aims to identify whether ecological selection (based on physiology, behavior, habitat, etc.) plays a role in the long‐term survival of corals during the late Paleocene and early Eocene. The late Paleocene‐early Eocene interval is associated with multiple hyperthermal events that correspond to rises in atmospheric pCO2 and sea surface temperature, ocean acidification, and increases in weathering and turbidity. Coral reefs are rare during the late Paleocene and early Eocene, but despite the lack of reef habitat, corals do not experience an extinction at the generic level and there is little extinction at the species level. In fact, generic and species richness increases throughout the late Paleocene and early Eocene. We show that corals with certain traits (coloniality, carnivorous, or suspension feeding diet, hermaphroditic brooding reproduction, living in clastic settings) are more likely to survive climate change in the early Eocene. These findings have important implications for modern coral ecology and allow us to make more nuanced predictions about which taxa will have higher extinction risk in present‐day climate change.

Coral Fish Ecology Syngnathidae as Ecotourism Supporting Power in Blue Lagoon Coastal Waters Karangasem, Bali

The Syngnathidae reef fish belongs to the vulnerable category of CITES due to the decrease in its original habitat. This is due to the high activity of predatory and utilization as raw material of traditional medicine. This study aims to study the ecological conditions including the distribution and abundance of reef fish Syngnathidae in the waters of the Blue Lagoon Karangasem waters and study the physical condition of its aquatic chemistry. This research was conducted from August to October 2017. The determination of research station was done based on Purposive sampling methods. For data retrieval of the Syngnathidae reef fish using square squares method with size 10x10 m in each sampling location. The result of this research is the emergence of species of reef fish Syngnathidae ranged from 1-4 individual at each location of observation. The results show that the ecological condition of the Syngnathidae reef fish in the Blue Lagoon coastal waters is of concern, this refers to the distribution and abundance of the limited reef fish Syngnathidae in its distribution. On the other hand, analysis of physical chemistry data shows that the condition of Blue Lagoon coastal waters tends to be stable. Measurement of water physics-chemical parameters obtained result of temperature measurement range 28-29oC, salinity 27-29 ppt, pH 7.08-7,89 and DO 7-7,75 mg/l. The result of physicochemical parameter measurement is related to the quality standard of Kep.Men.LH No.51 about the quality of the waters for marine biota was good for the existence of Syngnathidae reef fish. In general, the aquatic chemical physics conditions have a significant influence on the emergence of reef fish Syngnathidae found in stations 1 and III but not found in station II located in the middle of the waters between stations I and III.

Study of Total Lipidome of the Sinularia siaesensis Soft Coral

The rapid development of lipidomics of human and higher animals stimulated the study of the lipidome of certain groups of marine organisms. Soft corals are an integral part of the tropical and cold-water ecosystems of the World Ocean, but there is almost no data on the lipidome of these animals. The total lipidome of a tropical soft coral Sinularia siaesensis (Cnidaria: Anthozoa: Octocorallia: Alcionacea) containing intracellular symbiotic microalgae (zooxanthellae) was studied by gas and liquid chromatography-mass spectrometry. The structure and content of 144 molecular species of the main classes of acyl lipids of this alcyonaria were determined, including waxes, triglycerides (TG), monoalkyldiacylglycerides (MADAG), ethanolamine, choline, serine, and inositol glycerophospholipids (PE, PC, PS, and PI), ceramide aminoethylphosphonate (CAEP), sulfoquinovosyldiacylglyceride (SQDG), and mono- and digalactosyldiacylglycerides (MGDG and DGDG). The main components of S. siaesensis lipids were waxes 16:0/16:0, 16:0/18:0, and 18:0/16:0; TG 16:0/16:0/16:0 and 16:2/16:0/16:0; MADAG 18:0e/16:0/16:0, 16:0e/16:0/18:0, and 16:0e/16:0/16:0; and PS 18:0e/24:5, lyso-PC 18:0e, PE 18:1e/20:4, PC 18:0e/20:4, CAEP 18:2b/16:0, SQDG 14:0/16:0, and PI 18:0/24:5. The dominance of saturated waxes in reserve lipids is a species-specific feature of tropical alcyonarians. Waxes are synthesized in the host organism, and zooxanthellae can increase the proportion of saturated waxes by transferring saturated fatty acids (FA). The residues of polyunsaturated FA (PUFA) are found in the molecules of TG and MADAG, mainly in the sn-1 and sn-2 positions, respectively. Detection of MADAG with residues of marker FA of zooxanthellae (18:0e/18:3/16:0, 18:0e/18:4/16:0, and 16:0e/18:3/16:0) confirms the transfer of PUFA from the symbionts to the host. Tetracosapolyenoic FA, which is a chemotaxonomic markers of octocorals, are concentrated in molecular species of PS and PI. Most molecular species of PE, PC, and PS are in alkylacyl form, while for PI molecules, a diacyl form is characteristic. A significant proportion of MGDG, DGDG, and SQDG points to the importance of zooxanthellae in the formation of the lipid profile of symbiotic soft corals. Determination of the profile of lipid molecular species requires the development of a lipidomic approach in the study of biochemistry and ecology of corals and other cnidarians.

Coral microbiome database: Integration of sequences reveals high diversity and relatedness of coral-associated microbes.

SummaryCoral‐associated microorganisms are thought to play a fundamental role in the health and ecology of corals, but understanding of specific coral–microbial interactions are lacking. In order to create a framework to examine coral–microbial specificity, we integrated and phylogenetically compared 21,100 SSU rRNA gene Sanger‐produced sequences from bacteria and archaea associated with corals from previous studies, and accompanying host, location and publication metadata, to produce the Coral Microbiome Database. From this database, we identified 39 described and candidate phyla of Bacteria and two Archaea phyla associated with corals, demonstrating that corals are one of the most phylogenetically diverse animal microbiomes. Secondly, this new phylogenetic resource shows that certain microorganisms are indeed specific to corals, including evolutionary distinct hosts. Specifically, we identified 2–37 putative monophyletic, coral‐specific sequence clusters within bacterial genera associated with the greatest number of coral species (Vibrio, Endozoicomonas and Ruegeria) as well as functionally relevant microbial taxa (“Candidatus Amoebophilus”, “Candidatus Nitrosopumilus” and under recognized cyanobacteria). This phylogenetic resource provides a framework for more targeted studies of corals and their specific microbial associates, which is timely given the escalated need to understand the role of the coral microbiome and its adaptability to changing ocean and reef conditions.

4 サンゴの生態に関与する特異な天然有機分子の多様性(口頭発表の部)

4 サンゴの生態に関与する特異な天然有機分子の多様性(口頭発表の部)

A comparison of two common sample preparation techniques for lipid and fatty acid analysis in three different coral morphotypes reveals quantitative and qualitative differences.

Lipids are involved in a host of biochemical and physiological processes in corals. Therefore, changes in lipid composition reflect changes in the ecology, nutrition, and health of corals. As such, accurate lipid extraction, quantification, and identification is critical to obtain comprehensive insight into a coral’s condition. However, discrepancies exist in sample preparation methodology globally, and it is currently unknown whether these techniques generate analogous results. This study compared the two most common sample preparation techniques for lipid analysis in corals: (1) tissue isolation by air-spraying and (2) crushing the coral in toto. Samples derived from each preparation technique were subsequently analysed to quantify lipids and their constituent classes and fatty acids in four common, scleractinian coral species representing three distinct morphotypes (Acropora millepora, Montipora crassotuberculata, Porites cylindrica, and Pocillopora damicornis). Results revealed substantial amounts of organic material, including lipids, retained in the skeletons of all species following air-spraying, causing a marked underestimation of total lipid concentration using this method. Moreover, lipid class and fatty acid compositions between the denuded skeleton and sprayed tissue were substantially different. In particular, the majority of the total triacylglycerol and total fatty acid concentrations were retained in the skeleton (55–69% and 56–64%, respectively). As such, the isolated, sprayed tissue cannot serve as a reliable proxy for lipid quantification or identification in the coral holobiont. The in toto crushing method is therefore recommended for coral sample preparation prior to lipid analysis to capture the lipid profile of the entire holobiont, permitting accurate diagnoses of coral condition.

English

English

The roles of endolithic fungi in bioerosion and disease in marine ecosystems. I. General concepts

ABSTRACTEndolithic true fungi and fungus-like microorganisms penetrate calcareous substrates formed by living organisms, cause significant bioerosion and are involved in diseases of many host animals in marine ecosystems. A theoretical interactive model for the ecology of reef-building corals is proposed in this review. This model includes five principle partners that exist in a dynamic equilibrium: polyps of a colonial coelenterate, endosymbiotic zooxanthellae, endolithic algae (that penetrate coral skeletons), endolithic fungi (that attack the endolithic algae, the zooxanthellae and the polyps) and prokaryotic and eukaryotic microorganisms (which live in the coral mucus). Endolithic fungi and fungus-like boring microorganisms are important components of the marine calcium carbonate cycle because they actively contribute to the biodegradation of shells of animals composed of calcium carbonate and calcareous geological substrates.

Key functional role of the optical properties of coral skeletons in coral ecology and evolution.

Multiple scattering of light on coral skeleton enhances light absorption efficiency of coral symbionts and plays a key role in the regulation of their internal diffuse light field. To understand the dependence of this enhancement on skeleton meso- and macrostructure, we analysed the scattering abilities of naked coral skeletons for 74 Indo-Pacific species. Sensitive morphotypes to thermal and light stress, flat-extraplanate and branching corals, showed the most efficient structures, while massive-robust species were less efficient. The lowest light-enhancing scattering abilities were found for the most primitive colonial growth form: phaceloid. Accordingly, the development of highly efficient light-collecting structures versus the selection of less efficient but more robust holobionts to cope with light stress may constitute a trade-off in the evolution of modern symbiotic scleractinian corals, characterizing two successful adaptive solutions. The coincidence of the most important structural modifications with epitheca decline supports the importance of the enhancement of light transmission across coral skeleton in modern scleractinian diversification, and the central role of these symbioses in the design and optimization of coral skeleton. Furthermore, the same ability that lies at the heart of the success of symbiotic corals as coral-reef-builders can also explain the 'Achilles's heel' of these symbioses in a warming ocean.

COMPARISON OF COMMERCIAL STRUCTURE-FROM-MOTION PHOTOGRAMMETY SOFTWARE USED FOR UNDERWATER THREE-DIMENSIONAL MODELING OF CORAL REEF ENVIRONMENTS

Abstract. Structural complexity in ecosystems creates an assortment of microhabitat types and has been shown to support greater diversity and abundance of associated organisms. The 3D structure of an environment also directly affects important ecological parameters such as habitat provisioning and light availability and can therefore strongly influence ecosystem function. Coral reefs are architecturally complex 3D habitats, whose structure is intrinsically linked to the ecosystem biodiversity, productivity, and function. The field of coral ecology has, however, been primarily limited to using 2-dimensional (2D) planar survey techniques for studying the physical structure of reefs. This conventional approach fails to capture or quantify the intricate structural complexity of corals that influences habitat facilitation and biodiversity. A 3-dimensional (3D) approach can obtain accurate measurements of architectural complexity, topography, rugosity, volume, and other structural characteristics that affect biodiversity and abundance of reef organisms. Structurefrom- Motion (SfM) photogrammetry is an emerging computer vision technology that provides a simple and cost-effective method for 3D reconstruction of natural environments. SfM has been used in several studies to investigate the relationship between habitat complexity and ecological processes in coral reef ecosystems. This study compared two commercial SfM software packages, Agisoft Photoscan Pro and Pix4Dmapper Pro 3.1, in order to assess the cpaability and spatial accuracy of these programs for conducting 3D modeling of coral reef habitats at three spatial scales.

A new sequence data set of SSU rRNA gene for Scleractinia and its phylogenetic and ecological applications.

Scleractinian corals (i.e. hard corals) play a fundamental role in building and maintaining coral reefs, one of the most diverse ecosystems on Earth. Nevertheless, their phylogenies remain largely unresolved and little is known about dispersal and survival of their planktonic larval phase. The small subunit ribosomal RNA (SSU rRNA) is a commonly used gene for DNA barcoding in several metazoans, and small variable regions of SSU rRNA are widely adopted as barcode marker to investigate marine plankton community structure worldwide. Here, we provide a large sequence data set of the complete SSU rRNA gene from 298 specimens, representing all known extant reef coral families and a total of 106 genera. The secondary structure was extremely conserved within the order with few exceptions due to insertions or deletions occurring in the variable regions. Remarkable differences in SSU rRNA length and base composition were detected between and within acroporids (Acropora, Montipora, Isopora and Alveopora) compared to other corals. The V4 and V9 regions seem to be promising barcode loci because variation at commonly used barcode primer binding sites was extremely low, while their levels of divergence allowed families and genera to be distinguished. Atime-calibrated phylogeny of Scleractinia is provided, and mutation rate heterogeneity is demonstrated across main lineages. The use of this data set as a valuable reference for investigating aspects of ecology, biology, molecular taxonomy and evolution of scleractinian corals is discussed.

A novel application of a cryosectioning technique to undecalcified coral specimens

Histological observations represent an important application to directly characterize the structure of tissues and locate host-associated and invasive microorganisms. Histological approaches have been widely employed in studies of the physiology, pathology and ecology of corals. However, the conventional preparation of histological sections requires decalcification of coral samples to remove the hard skeletal structure in a series of acid or EDTA solutions over a weeks’ period, causing potential disturbances in coral structures on prepared slides. In this study, we present an alternative method to prepare thin sections from undecalcified frozen coral tissues, which has been developed for retaining the structural integrity of histological sections including skeleton. Cross sections of normal and diseased (rapid tissue necrosis and black band disease) coral specimens prepared with this method displayed the complete structure of the coral fragments including soft tissues and skeleton structure at microscopic scales, thereby clearly showing the orientation of damaged tissues and associated microorganisms in relation to skeletal structures. This study demonstrates that the present cryosectioning method without the need for decalcification is a highly effective tool for in-depth understanding of coral tissue/skeleton interactions.

Molecular trophic markers in marine food webs and their potential use for coral ecology

Notable advances in ecological genomics have been driven by high-throughput sequencing technology and taxonomically broad sequence repositories that allow us to accurately assess species interactions with great taxonomic resolution. The use of DNA as a marker for ingested food is particularly relevant to address predator–prey interactions and disentangle complex marine food webs. DNA-based methods benefit from reductionist molecular approaches to address ecosystem scale processes, such as community structure and energy flow across trophic levels, among others. Here we review how molecular trophic markers have been used to better understand trophic interactions in the marine environment and their advantages and limitations. We focus on animal groups where research has been focused, such as marine mammals, seabirds, fishes, pelagic invertebrates and benthic invertebrates, and use case studies to illustrate how DNA-based methods unraveled food-web interactions. The potential of molecular trophic markers for disentangling the complex trophic ecology of corals is also discussed.

Relationships between growth, population dynamics, and environmental parameters in the solitary non-zooxanthellate scleractinian coral Caryophyllia inornata along a latitudinal gradient in the Mediterranean Sea

The ecology of scleractinian corals may be understood through comparisons between population demographic data and environmental parameters. Growth (growth constant and maximum size) and demographic parameters (population structure stability, instantaneous mortality rate, average age of individuals, percentage of immature individuals, age at maximum biomass, and average age of biomass) of the solitary, non-zooxanthellate, and temperate coral Caryophyllia inornata were investigated at six sites along an 8° latitudinal gradient of temperature and solar radiation (SR) on the western Italian coasts. Growth parameters were homogeneous among populations across the investigated latitudinal range. While demographic parameters were not correlated with depth temperature, populations were progressively less stable and showed a deficiency of young individuals with increasing SR, likely as a result of the lowered energetic resources due to reduced zooplankton availability. These results contrast with data from another Mediterranean non-zooxanthellate solitary coral, Leptopsammia pruvoti, investigated along the same gradient, which shows no correlation between population demography and temperature or SR.