scholarly journals Changes in Coral Skeleton Growth Recorded by Density Band Stratigraphy, Crystalline Structure, and Hiatuses

2021 ◽  
Vol 8 ◽  
Author(s):  
Kyle W. Fouke ◽  
Jeffrey M. Trop ◽  
Mayandi Sivaguru
Keyword(s):  
Keystone Species ◽  
Coral Growth ◽  
Coral Skeleton ◽  
Coral Skeletons ◽  
Fringing Reefs ◽  
Growth History ◽  
Density Band ◽  
Large Coral ◽  
The Caribbean ◽  
Stratigraphic Sequences

Next-generation high resolution brightfield microscopy, x-radiography, and microcomputed tomography (microCT) analyses indicate that coral skeleton high density band (HDB) and low density band (LDB) stratigraphic sequences record dynamic changes in coral growth history. HDB-LDB sequences were studied within three small heads of Orbicella annularis, an ecological keystone species in the Caribbean Sea, collected from the leeward fringing reefs on Curaçao. Results indicate that HDB layers are formed by the thickening of exothecal and endothecal dissepiments, costae, and theca located at the margin and external to individual skeletal cups (corallites). Conversely, septa and columellas located inside individual corallites do not change in thickness. HDB-LDB stratigraphic sequences were laterally traced from the center to the margins of individual coral heads, demonstrating that shifts took place in the trajectory of coral skeleton growth. Normal HDB layers in the center of individual coral heads are formed at the same time (age-equivalent) as surfaces of erosion and no skeleton growth (hiatuses) on the margins of the heads. These hiatus surfaces within HDB-LDB stratal geometries indicate that multiple marine ecological and environmental processes affect the orientation, size, shape, and geometry of coral skeletons during coral growth history. The presence of these hiatus surfaces in other large coral heads would strongly impact sclerochronology and the interpretation of multiple environmental factors including sea surface temperature (SST).

scholarly journals A genomic view of coral-associated Prosthecochloris and a companion sulfate-reducing bacterium

2019 ◽  
Author(s):  
Yu-Hsiang Chen ◽  
Shan-Hua Yang ◽  
Kshitij Tandon ◽  
Chih-Ying Lu ◽  
Hsing-Ju Chen ◽  
...  
Keyword(s):  
Environmental Changes ◽  
Sulfur Metabolism ◽  
Genomic Analysis ◽  
Coral Skeleton ◽  
Pigment Synthesis ◽  
Sulfate Reducing ◽  
Coral Skeletons ◽  
Functional Genomic Analysis ◽  
Ecological Roles ◽  
Isopora Palifera

AbstractEndolithic microbial symbionts in the coral skeleton may play a pivotal role in maintaining coral health. However, compared to aerobic microorganisms, research on the roles of endolithic anaerobic microorganisms and microbe-microbe interactions in the coral skeleton are still in their infancy. In our previous study, we showed that a group of coral-associated Prosthecochloris (CAP), a genus of anaerobic green sulfur bacteria, was dominant in the skeleton of the coral Isopora palifera. Though CAP is diverse, the 16S rRNA phylogeny presents it as a distinct clade separate from other free-living Prosthecochloris. In this study, we build on previous research and further characterize the genomic and metabolic traits of CAP by recovering two new near-complete CAP genomes—Candidatus Prosthecochloris isoporaea and Candidatus Prosthecochloris sp. N1—from coral Isopora palifera endolithic cultures. Genomic analysis revealed that these two CAP genomes have high genomic similarities compared with other Prosthecochloris and harbor several CAP-unique genes. Interestingly, different CAP species harbor various pigment synthesis and sulfur metabolism genes, indicating that individual CAPs can adapt to a diversity of coral microenvironments. A novel near-complete SRB genome—Candidatus Halodesulfovibrio lyudaonia—was also recovered from the same culture. The fact that CAP and various sulfate-reducing bacteria (SRB) co-exist in coral endolithic cultures and coral skeleton highlights the importance of SRB in the coral endolithic community. Based on functional genomic analysis of Ca. P. sp. N1 and Ca. H. lyudaonia, we also propose a syntrophic relationship between the SRB and CAP in the coral skeleton.ImportanceLittle is known about the ecological roles of endolithic microbes in the coral skeleton; one potential role is as a nutrient source for their coral hosts. Here, we identified a close ecological relationship between CAP and SRB. Recovering novel near-complete CAP and SRB genomes from endolithic cultures in this study enabled us to understand the genomic and metabolic features of anaerobic endolithic bacteria in coral skeletons. These results demonstrate that CAP members with similar functions in carbon, sulfur, and nitrogen metabolisms harbor different light-harvesting components, suggesting that CAP in the skeleton adapts to niches with different light intensities. Our study highlights the potential ecological roles of CAP and SRB in coral skeletons and paves the way for future investigations into how coral endolithic communities will respond to environmental changes.

scholarly journals Reviews and syntheses: Revisiting the boron systematics of aragonite and their application to coral calcification

2018 ◽  
Vol 15 (9) ◽  
pp. 2819-2834 ◽  
Author(s):  
Thomas M. DeCarlo ◽  
Michael Holcomb ◽  
Malcolm T. McCulloch
Keyword(s):  
Partition Coefficient ◽  
Isotopic Fractionation ◽  
Computer Code ◽  
Comprehensive Analysis ◽  
Coral Skeleton ◽  
Carbonate Chemistry ◽  
Carbonate System ◽  
Coral Skeletons ◽  
User Friendly ◽  
Propagation Of Uncertainties

Abstract. The isotopic and elemental systematics of boron in aragonitic coral skeletons have recently been developed as a proxy for the carbonate chemistry of the coral extracellular calcifying fluid. With knowledge of the boron isotopic fractionation in seawater and the B∕Ca partition coefficient (KD) between aragonite and seawater, measurements of coral skeleton δ11B and B∕Ca can potentially constrain the full carbonate system. Two sets of abiogenic aragonite precipitation experiments designed to quantify KD have recently made possible the application of this proxy system. However, while different KD formulations have been proposed, there has not yet been a comprehensive analysis that considers both experimental datasets and explores the implications for interpreting coral skeletons. Here, we evaluate four potential KD formulations: three previously presented in the literature and one newly developed. We assess how well each formulation reconstructs the known fluid carbonate chemistry from the abiogenic experiments, and we evaluate the implications for deriving the carbonate chemistry of coral calcifying fluid. Three of the KD formulations performed similarly when applied to abiogenic aragonites precipitated from seawater and to coral skeletons. Critically, we find that some uncertainty remains in understanding the mechanism of boron elemental partitioning between aragonite and seawater, and addressing this question should be a target of additional abiogenic precipitation experiments. Despite this, boron systematics can already be applied to quantify the coral calcifying fluid carbonate system, although uncertainties associated with the proxy system should be carefully considered for each application. Finally, we present a user-friendly computer code that calculates coral calcifying fluid carbonate chemistry, including propagation of uncertainties, given inputs of boron systematics measured in coral skeleton.

scholarly journals Ferromagnetic Resonance Spectroscopy and Rock Magnetic Characterization of Fossil Coral Skeletons in Ishigaki Islands, Japan

Geosciences ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 400
Author(s):  
Yuho Kumagai ◽  
Norihiro Nakamura ◽  
Tetsuro Sato ◽  
Toshitaka Oka ◽  
Hirokuni Oda
Keyword(s):  
Ferromagnetic Resonance ◽  
Single Domain ◽  
Coral Skeleton ◽  
Resonance Spectroscopy ◽  
Continuous Growth ◽  
Coral Skeletons ◽  
Ishigaki Island ◽  
Biogenic Magnetite ◽  
A Chain ◽  
Fossil Coral

Skeletons of hermatypic corals (e.g., Porites) might have enormous potential as a high-resolution paleomagnetic recorder owing to their rapid and continuous growth over hundreds of years at a rate of up to 2 cm/year, although typical corals show an extremely weak intensity of remanence and low stability. We found that coral tsunami boulders with negligible amounts of calcite on Ishigaki Island show a measurable intensity of remanence; thus, we attempted to characterize the magnetic assemblages in this coral skeleton to determine whether it is of biogenic or detrital magnetite using first-order reversal curve (FORC) measurements, ferromagnetic resonance (FMR) spectroscopy, and petrological observations through field-emission type scanning electron microscope (FE-SEM) with an acid treatment. The FMR derivative spectra of coral skeleton samples represent multiple derivative maxima and extended low-field absorption, indicating the presence of intact biogenic magnetite chains. FORC diagrams represent a “central ridge” signature with a vertical spread. These FMR and FORC features indicate the magnetization of these coral skeletons that are mainly created using intact biogenic magnetites and mixtures of grains from collapsed biogenic magnetites, pseudo-single domain grains, and multi-domain grains such as detrital magnetite. FE-SEM observations confirm the presence of a chain-like structure of iron oxides corresponding to the features of biogenic magnetite. Therefore, the magnetic mineral assemblage in coralline boulders from Ishigaki Island consists of dominant biogenic-origin single-domain magnetite and a trace amount of detrital component, indicating that fossil coral skeletons in Ishigaki Island have potential for utilization in paleomagnetic studies.

Sipunculans associated with dead coral skeletons in the Santa Marta region of Colombia, south-western Caribbean

2013 ◽  
Vol 93 (7) ◽  
pp. 1785-1793 ◽  
Author(s):  
Carlos E. Gómez ◽  
Néstor E. Ardila ◽  
Adolfo Sanjuan-Muñoz
Keyword(s):  
Coral Reef ◽  
Abundant Species ◽  
Caribbean Region ◽  
Dead Coral ◽  
Discrete Component ◽  
Massive Coral ◽  
Coral Skeletons ◽  
Montastraea Annularis ◽  
Western Caribbean ◽  
The Caribbean

Sipunculans represent a discrete component of the coral reef ecosystem, since they live inside the calcareous structure. They are an important component in terms of biomass and number of organisms. The present study describes the diversity of sipunculans living inside massive coral skeletons. A total of 43 blocks of dead coral skeletons from Montastraea cavernosa, Montastraea annularis and Diploria strigosa were collected from nearby coral reef areas off Santa Marta, on the Colombian Caribbean coast. Using hammer and chisel, blocks of approximately 1 dm3 were broken into small pieces, from which the sipunculans were extracted. A total of 381 organisms were obtained from the coral blocks comprising four families and 10 species. All the species found have been widely reported in different studies from the Caribbean region. Aspidosiphon fischeri and Phascolosoma perlucens were the two most abundant species comprising more than 60% of the total organisms with a mean density of 18.52 ± 4.64 organisms dm−3. Dead coral substrate from M. cavernosa had the greatest abundance (N = 148), followed by D. strigosa (N = 121) and M. annularis (N = 112). There were no significant differences in the abundance, richness, and diversity of sipunculans between coral skeletons; and within samples there was high variability suggesting that the skeletal substrates analysed came from coral skeletons of different unknown ages of succession. These results describe the sipunculan community structure that live inside three important massive coral skeletons, and contributes to the knowledge of the cryptobiota diversity of the Santa Marta area of Colombia.

scholarly journals LITHOPHAGA NIGRA (D’ORBIGNY, 1853) (MOLLUSCA: BIVALVIA: MYTILIDAE), FIRST RECORD FOR THE COLOMBIAN CARIBBEAN

2016 ◽  
Vol 36 ◽  
Author(s):  
Carlos E. Gómez Soto ◽  
Tatiana Rico ◽  
Néstor E. Ardila ◽  
Adolfo Sanjuan Muñoz
Keyword(s):  
Caribbean Sea ◽  
First Record ◽  
Dead Coral ◽  
Coral Skeletons ◽  
The Caribbean ◽  
First Time

Lithophaga nigra (d’Orbigny, 1853) is an uncommon boring bivalve that inhabits dead coral skeletons and occurs in the Caribbean Sea and the Indopacific region. One specimen of this species was collected within a dead head of the coral Montastraea sp. in Playa Blanca, (bahía de Gaira) near Santa Marta at 10 m of depth, and it is recorded for the first time in the Colombian Caribbean.

scholarly journals Reviews and syntheses: Revisiting the boron systematics of aragonite and their application to coral calcification

2018 ◽  
Author(s):  
Thomas M. DeCarlo ◽  
Michael Holcomb ◽  
Malcolm T. McCulloch
Keyword(s):  
Partition Coefficient ◽  
Isotopic Fractionation ◽  
Computer Code ◽  
Comprehensive Analysis ◽  
Coral Skeleton ◽  
Carbonate Chemistry ◽  
Carbonate System ◽  
Coral Skeletons ◽  
User Friendly ◽  
Propagation Of Uncertainties

Abstract. The isotopic and elemental systematics of boron in aragonitic coral skeletons have recently been developed as a proxy for the carbonate chemistry of the coral extracellular calcifying fluid. With knowledge of the boron isotopic fractionation in seawater and the B / Ca partition coefficient (KD) between aragonite and seawater, measurements of coral skeleton δ11B and B / Ca can potentially constrain the full carbonate system. Two sets of abiogenic aragonite precipitation experiments designed to quantify KD have recently made possible the application of this proxy system. However, while different KD formulations have been proposed, there has not yet been a comprehensive analysis that considers both experimental datasets and explores the implications for interpreting coral skeletons. Here, we evaluate four potential KD formulations: three previously presented in the literature and one newly developed. We assess how well each formulation reconstructs the known fluid carbonate chemistry from the abiogenic experiments, and we evaluate the implications for deriving the carbonate chemistry of coral calcifying fluid. Three of the KD formulations performed similarly when applied to abiogenic aragonites precipitated from seawater and to coral skeletons. Critically, we find that some uncertainty remains in understanding the mechanism of boron elemental partitioning between aragonite and seawater, and addressing this question should be a target of additional abiogenic precipitation experiments. Despite this, boron systematics can already be applied to quantify the coral calcifying fluid carbonate system, although uncertainties associated with the proxy system should be carefully considered for each application. Finally, we present a user-friendly computer code that calculates coral calcifying fluid carbonate chemistry, including propagation of uncertainties, given inputs of boron systematics measured in coral skeleton.

scholarly journals Ceiba pentandra L. Gaertn. (Malvaceae) and associated species: Spiritual Keystone Species of the Neotropics

Botany ◽  
2021 ◽  
Author(s):  
M.-A. Tareau ◽  
A. Greene ◽  
Guillaume Odonne ◽  
D. Davy
Keyword(s):  
Related Species ◽  
Keystone Species ◽  
Ceiba Pentandra ◽  
The Caribbean ◽  
Associated Species ◽  
First Time ◽  
Axis Mundi

Among the 18 species included in the Ceiba genus, in the Malvaceae (Bombacoideae) family, Ceiba pentandra L. Gaertn. is not only the tallest and most widespread, but also occupies the most prominent place in Neotropical cosmovisions. In this ethnobotanical review, we compare perceptions and uses of Ceiba and related species across indigenous and Afro-descendant cultures ranging from the Caribbean to the Argentinian Chaco. Ceiba's widely-shared role as axis mundi, (particularly in Amazonia) psychopomp and shelter of major forest spirits makes it a perfect example of a Spiritual Keystone Species, a new concept inspired from Cultural Keystone Species and defined here for the first time.

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