Coral Diversity Research Articles

A Comparative Study on Pelagic Primary Productivity in the Coastal Areas of Eritrean Red Sea

Primary Productivity is the process by which inorganic forms of carbon are synthesized by living organisms into simple organic compounds. Most carbon on Earth is in inorganic oxidized forms such as carbon dioxide (CO2), bicarbonate (HCO3-), and carbonate (CO3). Inorganic carbon must be chemically reduced to form the organic molecules which are the building blocks of life and the mechanism by which energy is stored in living organisms. Eritrea’s coastal and marine ecosystems are characterized by rich and diverse coral reefs, isolated mangrove forests, sea-grass beds, bays, beaches and pristine unpolluted waters that are at the critical juncture between development and conservation. These ecosystems represent a physical resource base for the potentially rich and unexploited marine fisheries. This study is basically aimed at the measurement of primary productivity in relation to fisheries. The study results will also high light the plankton assemblage of a coastal environment and this study will also examine the productivity of the coastal environment.

The origin and evolution of coral species richness in a marine biodiversity hotspot.

The Coral Triangle (CT) region of the Indo-Pacific realm harbors an extraordinary number of species, with richness decreasing away from this biodiversity hotspot. Despite multiple competing hypotheses, the dynamics underlying this regional diversity pattern remain poorly understood. Here, we use a time-calibrated evolutionary tree of living reef coral species, their current geographic ranges, and model-based estimates of regional rates of speciation, extinction, and geographic range shifts to show that origination rates within the CT are lower than in surrounding regions, a result inconsistent with the long-standing center of origin hypothesis. Furthermore, endemism of coral species in the CT is low, and the CT endemics are older than relatives found outside this region. Overall, our model results suggest that the high diversity of reef corals in the CT is largely due to range expansions into this region of species that evolved elsewhere. These findings strongly support the notion that geographic range shifts play a critical role in generating species diversity gradients. They also show that preserving the processes that gave rise to the striking diversity of corals in the CT requires protecting not just reefs within the hotspot, but also those in the surrounding areas.

Exposure of coastal ecosystems to river plume spreading across a near-equatorial continental shelf

The Berau Continental Shelf (BCS) in East Kalimantan, Indonesia, harbours various tropical marine ecosystems, including mangroves, seagrass meadows and coral reefs. These ecosystem are located partly within reach of the Berau River plume, which may affect ecosystem health through exposure to land-derived sediments, nutrients and pollutants carried by the plume. This study aims (1) to assess the exposure risk of the BCS coastal ecosystems to river plume water, measured as exposure time to three different salinity levels, (2) to identify the relationships between these salinity levels and the abundance and diversity of coral and seagrass ecosystems, and (3) to determine a suitable indicator for the impacts of salinity on coral reef and seagrass health. We analysed hydrodynamic models, classified salinity levels, and quantified the correlations between the salinity model parameters and ecological metrics for the BCS systems. An Empirical Orthogonal Functions (EOF) analysis revealed three modes of river plume dispersal patterns, which strongly reflect monsoon seasonality. The first mode, explaining 39% of the variability, was associated with the southward movement of the plume due to northerly winds, while the second and third modes (explaining 29% and 26% of the variability, respectively) were associated with the northeastward migration of the plume related to southwesterly and southerly winds. Exposure to low salinity showed higher correlations with biological indicators than mean salinity, indicating that low salinity is a more suitable indicator for coastal ecosystem health. Significant correlations (R2) were found between exposure time to low salinity (days with salinity values below 25 PSU) with coral cover, coral species richness, seagrass cover, the number of seagrass species, seagrass leaf phosphorus, nitrogen, C:N ratio and iron content. By comparing the correlation coefficients and the slopes of the regression lines, our study suggests that coral reefs are more susceptible to low salinity levels exposure than seagrass meadows. Regarding the risk of corals being exposed to low salinity, nearshore and northern barrier reefs were classified as “high risk”, the middle barrier reef as “medium to high risk” and southern barrier reefs as “medium risk”. Further offshore, the oceanic reefs were classified as “low risk”. Regarding the seagrass meadows, the nearshore region was categorized as “high risk”, the barrier reef as “medium to low risk” and oceanic reefs as “low risk”. This study contributes to assessing the potential impacts of salinity on the BCS ecosystems, and further provides a knowledge base for marine conservation planning.

Quaternary fossil coral communities in uplifted strata along the Balochistan coast of Pakistan: understanding modern coral decline in the Arabian Sea

Uplifted reefs due to being important palaeoclimate archives and a rich source of information on past physical and geochemical changes globally have become the centre of marine research. The uplifted fossil Quaternary coral communities of Jiwani and Gwadar are perfect places to study the palaeoclimatic and geological changes that have shaped the Balochistan coast. Studies on the palaeodiversity of corals along the Makran coast of Pakistan are lacking. In the present study, the samples collected using line intercept method from four uplifted sites (Balochistan coast: one at Gwadar and three at Jiwani) were analysed. The relative distribution and diversity of scleractinian fossil corals was determined, and the factors responsible for coral decline along Pakistan coast were compared with modern coral distribution and diversity. A total of 48 fossil coral species were recorded in nine families and 22 genera. High coral diversity was recorded in the uplifted landward sites of Jiwani and Gwadar headland. Terraces close to the shore at Jiwani had lower diversity. The corals seem to be Quaternary: most likely Pleistocene to Holocene. The modern fauna lacks many species recorded in the fossil community, thus suggesting a faunal turnover in diversity and redistribution of coral fauna which may be linked with past geological events and increasing anthropogenic pressure.

Coral-algal Reef Complex of Vigoleno, Piacenza, Northern Italy

During the late Miocene, reef complexes characterised by poorly diversified coral associations (mainly Porites, occasionally associated with Tarbellastraea and/or Siderastraea), became widespread in the Mediterranean area. One of these complexes crops out at Vigoleno (Castell’Arquato, Piacenza, Northern Italy). According to the regional palaeogeographic and palinspastic reconstructions, it can be considered up to now the northernmost late Miocene (Tortonian-Messinian) reef of the Mediterranean area. Despite the limited outcropping and the faulting, the multidisciplinary investigations reveal the anatomy of this reef complex along two reference sections. In addition, a marked cyclicity characterises both carbonate and siliciclastic deposits of the Vigoleno wedge-top basin. At present, the lack of reliable geochronological markers and unsuitability of the material for stable isotope analyses are not sufficient to constrain the time-span and the main controlling environmental factors of these depositional cycles.

The black coral fauna (Cnidaria: Antipatharia) of Bermuda with new records.

The black coral fauna of Bermudan waters is poorly known, in large part due to the logistical challenges of surveying deep-water (>50 m) environments where most species occur. In 2016, the Nekton Expedition sought to survey the deep-water biodiversity around Bermuda using manned submersibles and mixed-gas technical SCUBA. A total of 28 black coral specimens were collected, and these were examined based on skeletal spine morphology, polyp morphology, colony branching pattern and in situ photographs. The specimens were assigned to seven species in three families and four genera, including (1) Antipathes atlantica Gray, 1857, (2) Antipathes furcata Gray, 1857, (3) Stichopathes pourtalesi Brook, 1889, (4) Stichopathes sp., (5) Distichopathes filix (Pourtales, 1867), (6) Tanacetipathes hirta (Gray, 1857), and (7) Tanacetipathes tanacetum (Pourtales, 1867). Of these, three species (Stichopathes sp., S. pourtalesi, and D. filix), one genus (Distichopathes) and one family (Aphanipathidae) are reported from Bermudan waters for the first time, thereby increasing the known black coral diversity of Bermuda to twelve species, five genera and four families. The diagnostic characters of the taxa identified as part of this study are illustrated and described.

Devonshire marbles: history of the industry and the geology of these classic British ornamental stones

Devonshire ‘marbles’ come from Mid– to Late Devonian limestones of south Devon, UK. They are not true marbles in the geological sense but were nonetheless tectonically buried during the Variscan orogenesis. They retain abundant palaeontological and sedimentological characters, overstamped by limited to extensive veining, deformation and brecciation. Recent work has revealed how these marbles have been used to decorate a wealth of buildings in Britain and overseas. There were two distinct industries, one that produced decorative marble for architectural use, and one that produced portable artefacts such as specimen marble tables and ornaments. The stones used in these two sister industries can be very different, a result of different sourcing of the same Devonshire limestones. A third industry sought to slice and polish local limestone pebbles to reveal their diverse coral, stromatoporoid and other fossil contents, and was aimed at tourists, collectors and museums. The history and early development of the marble industry are explored and the distinct characteristics of the stones used in Devonshire marble inlay are explained. The stones used in the parallel architectural trade are analysed elsewhere.

Characterization of diverse coral types using passive acoustic recorded data from the lagoon area of the Kavaratti—An atoll of the Lakshadweep archipelago

The presence of sound in marine habitats can be an indicator of biological processes. Therefore, sound monitoring of the reef system is important to develop an in-depth understanding of the biodiversity, vulnerabilities, and potential changes of ecosystems. In order to understand the diversity related to the coral types, we have computed Acoustic Complexity Index (ACI) (temporal and spectral scales) using passive acoustic recorded data from the lagoon area off the Kavaratti—an atoll of the Lakshadweep archipelago. ACI is found to be the highest in location “A” where the coral type of Acropora sp. and ample fish diversity is observed. In location “C” where massive Porites sp. and Pocillopora sp. with significant acoustic assemblages are observed, ACI was found to be comparatively lower than the location “A.” Whereas for “B,” “D,” and “E” locations, relatively low level of ACI index is obtained. The ACI is the lowest in location “B” where macroalgae with no fish species are seen. Among these three locations, “E” shows higher ACI due to the shrimp sound dominance in the rock substrate having Porite sp. coral type.

A review of biodiversity-related issues and challenges in megadiverse Indonesia and other Southeast Asian countries

Indonesia is one of the ten member states of the economically and politically diverse regional organization of the Association of Southeast Asian Nations (ASEAN). Southeast Asia comprises four of the 25 global biodiversity hotspots, three of the 17 global megadiverse countries (Indonesia, Malaysia, and the Philippines) and the most diverse coral reefs in the world. All member states are Parties to the Convention on Biological Diversity (CBD). We discuss ASEAN-wide joint activities on nature conservation and sustainable use of biodiversity that do not stop at national borders.The Indonesian archipelago comprises two of the world’s biodiversity hotspots (areas with a high degree of endemic species that are highly threatened by loss of habitats): Its insular character and complex geological history led to the evolution of a megadiverse fauna and flora on the global scale. The importance of biodiversity, e.g., in traditional medicine and agriculture, is deep-rooted in Indonesian society. Modern biodiversity pathways include new fields of application in technology, pharmacy and economy along with environmental policies. This development occurred not only in Indonesia but also in other biodiversity-rich tropical countries.This review summarizes and discusses the unique biodiversity of Indonesia from different angles (science, society, environmental policy, and bioeconomy) and brings it into context within the ASEAN region. The preconditions of each member state for biodiversity-related activities are rather diverse. Much was done to improve the conditions for biodiversity research and use in several countries, primarily in those with a promising economic development. However, ASEAN as a whole still has further potential for more joint initiatives. Especially Indonesia has the highest biodiversity potential within the ASEAN and beyond, but likewise the highest risk of biodiversity loss.We conclude that Indonesia has not taken full advantage of this potential yet. A growing national interest in local biodiversity as a natural resource is a welcome development on one hand, but the risk of too many restrictions for, e.g., the science community (high level of bureaucracy at all project stages from planning phase, visa procedures, field work permits, scientific exchange and project managment issues, governmental budget cuts for basic research and restricted access to international literature for Indonesian researchers) does significantly hamper the internationalization of biodiversity-related science. In the long run, Indonesia has to find a balance between protectionism and sensible access to its national biodiversity to tackle global challenges in biodiversity conservation, health issues, food security, and climate change.

Tracking trace elements into complex coral reef trophic networks

The integration, accumulation and transfer of trace elements across the main tropic levels of many food webs are poorly documented. This is notably the case for the complex trophic webs of coral reef ecosystems. Our results show that in the south-west lagoon of New Caledonia both abiotic (i.e. sediments) and biotic (i.e. primary producers, consumers and predators) compartments are contaminated by trace elements. However, our analyses revealed different contamination patterns from the sources of organic matter to the predators. The trophic levels involved in the sedimentary benthic food web (S-BFW, based on the sedimentary organic matter) and to a lesser extent in the reef benthic food web (R-BFW, based on algal turf) were mainly contaminated by trace elements that originate from mining activities like Ni and associated trace elements (Co, Cr, Fe, and Mn). Trace elements linked to agro-industrial (As, Hg, and Zn) and urban (Ag, Cd, Cu, Pb, Se, and V) activities were also integrated into the S-BFW, but preferentially into the R-BFW, and to a lesser extent into the detrital benthic food web (D-BFW, supplied by sea-grass plants). Most of the trace elements were biodiminished with increasing trophic levels along food webs. However, a marked biomagnification was observed for Hg, and suspected for Se and Zn. These results provide important baseline information to better interpret trace element contamination in the different organisms and trophic levels in a highly diversified coral reef lagoon.

Current biodiversity and ecological status of scleractinian corals of Sharm Obhur, Jeddah, Saudi Arabian coast of the Red Sea

The Sharm Obhur reefs have predominantly been populated by soft corals. Notably, the highest soft coral percentages were observed in the central region of the creek at Site 9 and Site 6, where anthropogenic activities are higher. Among the scleractinian corals, more non-acroporid corals such as Porites and Goniastrea were found at all study sites and were commonly observed in the creek entrance area. More acroporid corals were found at Site 7. The sedimentation rate of Sharm Obhur strongly influences the reef ecosystem. Site 9 continuously receives murky water from stormwater drainage channels and has the highest sedimentation rate in the creek, which kills most of the corals in the vicinity. Similarly, the dead end of Sharm Obhur (Site 8) also receives drainage water from the Wadi Al Kura channel, which makes this the second highest sedimentation zone of the creek. Although anthropogenic disturbances are higher in the creek, the diversity of the scleractinian corals is found to be remarkable. In this pilot study, 13 families, 34 genera and 66 species of scleractinian corals were identified.

Heritability of the Symbiodinium community in vertically- and horizontally-transmitting broadcast spawning corals

The dinoflagellate-coral partnership influences the coral holobiont’s tolerance to thermal stress and bleaching. However, the comparative roles of host genetic versus environmental factors in determining the composition of this symbiosis are largely unknown. Here we quantify the heritability of the initial Symbiodinium communities for two broadcast-spawning corals with different symbiont transmission modes: Acropora tenuis has environmental acquisition, whereas Montipora digitata has maternal transmission. Using high throughput sequencing of the ITS-2 region to characterize communities in parents, juveniles and eggs, we describe previously undocumented Symbiodinium diversity and dynamics in both corals. After one month of uptake in the field, Symbiodinium communities associated with A. tenuis juveniles were dominated by A3, C1, D1, A-type CCMP828, and D1a in proportional abundances conserved between experiments in two years. M. digitata eggs were predominantly characterized by C15, D1, and A3. In contrast to current paradigms, host genetic influences accounted for a surprising 29% of phenotypic variation in Symbiodinium communities in the horizontally-transmitting A. tenuis, but only 62% in the vertically-transmitting M. digitata. Our results reveal hitherto unknown flexibility in the acquisition of Symbiodinium communities and substantial heritability in both species, providing material for selection to produce partnerships that are locally adapted to changing environmental conditions.

Are Sri Lankan Reefs Losing the Resilience? An Example from Coral Reefs in Sallitive Island

Coral reefs are known to undergo phase shift in to macro-algae and reefs have lost the capacity to remain in or return to a coral-dominated state. This shift will not only affect corals, but the others heavily depend on heterogeneous habitat afforded by corals. Sallitivu in Panichchankerni, Eastern province, is a small island (41328 m2). The Island is surrounded by a ring of coral reef with an elevated breaking reef crest, seaward slope and centred shallow lagoon (<1.2m at high tide). The shore is entirely a thick layer of washed coral rubbles. The archived aerial photographs confirmed these coral rubbles present only after 2004 tsunami.Underwater visual census were carried out within the reef lagoon and three sites in reef slope using 30 m long belt transect. In addition to diversity of corals and algae, percentages of live, dead and bleached coral cover were recorded. The reef lagoon is shallow (10-60 cm) and much of the reef crest is exposed at low tide. Within the reef lagoon, the live coral cover was <5%. Around 15% was observed recently bleached, 12% were overgrown by algae; Padina sp, Halimeda sp, Sargassum sp, Caulerpa recemosa and Dictyota sp, and the rest was dead corals smothered by sediments. The seaward slope with high wave action was mostly smothered dead corals with live corals <3%. Coral colonies were represented by Acroporidae (branching and table corals)-Acropora cytherea, A. divaricata, A. formosa, A. gemmifera, A. grandis, A. hemprichii, A. hyacinthus, A. latistella, Acropora sp., A. nobilis, and A. robusta; (Foliaceous)-Montipora aequituberculata and M. hispida; Faviidae (sub massive and encrusting)-Favites halicora, Favites spinosa, Leptastrea purpurea and Platygyra daedalea; Pocilloporidae (Lace/cauliflower) -Pocillopora damicornis; Poritidae (Massive/submassive)-Porites evermanni, P. paliformis, and P. rus. Live corals observed were immature. Southern end of the reef slope had emerging corals among unstable coral rubbles. It is assumed that the degradation was started post-tsunami and continued due to natural stresses. The recovery of corals may hindered by macro-algal growth and resulting accumulation of sediments, smothering due to less wave action within reef lagoon and resulting recruitment and settlement failure. Recent bleaching would be due to exposure to direct sunlight during the change of tides and low sea level. Increasing oxygen level due to algal blooms would also prone for bleaching. Avoiding such undesirable phase shifts from coral dominance to algae and reverse them when occur, requires an urgent reform of scientific approaches to understand the processes causing the degradation. A better understanding on why some reefs rapidly degrade and others do not is critical. Most reef conservation efforts are directed toward reserve implementation, but new approaches are needed to sustain ecosystem function since demarcation of a marine reserve alone would not benefit in improving reef resilience.Keywords: Phase-shift, Coral reefs, Macro-algae, Bleaching, Sallitive Island

Pleistocene reefs of the Egyptian Red Sea: environmental change and community persistence.

The fossil record of Red Sea fringing reefs provides an opportunity to study the history of coral-reef survival and recovery in the context of extreme environmental change. The Middle Pleistocene, the Late Pleistocene, and modern reefs represent three periods of reef growth separated by glacial low stands during which conditions became difficult for symbiotic reef fauna. Coral diversity and paleoenvironments of eight Middle and Late Pleistocene fossil terraces are described and characterized here. Pleistocene reef zones closely resemble reef zones of the modern Red Sea. All but one species identified from Middle and Late Pleistocene outcrops are also found on modern Red Sea reefs despite the possible extinction of most coral over two-thirds of the Red Sea basin during glacial low stands. Refugia in the Gulf of Aqaba and southern Red Sea may have allowed for the persistence of coral communities across glaciation events. Stability of coral communities across these extreme climate events indicates that even small populations of survivors can repopulate large areas given appropriate water conditions and time.

Tectonic and environmental factors controlling on the evolution of Oligo-Miocene shallow marine carbonate factories along a tropical SE Circum-Caribbean

The evolution of the Cenozoic Circum-Caribbean shallow marine carbonate factories and ecosystems has been for long attributed to major global climatic and environmental changes. Although temporal variations in the Cenozoic shallow marine carbonate factories in this region seem to follow global trends, the potential effects of regional processes, such tectonic activity and local environmental change, on the evolution of the shallow marine carbonate factories are not well established. Here we present detailed sedimentologic and stratigraphic information from Middle Oligocene - Middle Miocene (Chattian-Burdigalian) shallow marine carbonate successions of the Siamana Formation in the Cocinetas sub-basin, Alta Guajira Basin, Guajira Peninsula, northern Colombia. We document the potential effects of regional tectonics and local environmental deterioration on the evolution of the Oligocene-Miocene tropical shallow marine carbonate factories along the SE Circum-Caribbean. Our results show that mixed heterozoan-photozoan biotic associations dominated the shallow marine carbonate factories during the Chattian, while purely photozoan biotic associations constituted the primary carbonate factory during the Aquitanian-Burdigalian transition. The Chattian mixed heterozoan/photozoan biotic association is associated with the development of mixed carbonate/siliciclastic shelves along which detached patchy reef areas occur. The onset of the Aquitanian-Burdigalian purely photozoan biotic associations parallels the increase in coral diversity as well as the occurence of rimmed/detached carbonate platforms in the northern part of the basin. The development of the rimmed/detached platforms coincides with a time of increased basin subsidence and increased silicilcastic input along the southernmost part of the basin. A significant change in the carbonate factory occurs in the Late Burdigalian, when purely heterozoan (rodalgal) biotic associations constituted the main shallow marine carbonate factory. This shift in the carbonate factory was favored by a major extensional component that resulted in subsidence and relative sea level rise along the Caribbean - South American margin. This extensional component is evidenced by the occurrence of normal faults that controlled the thickness and lateral extension of shallow marine rodalgal biostromes. The onset of the rodalgal biostromes, which elsewhere is associated with excellent carbonate reservoirs, also parallels the initiation of the Urumaco Trough and a further increase in silicilastic input toward the Cocinetas sub-basin. It also parallels a major tectonic reactivation along the Caribbean - South American plate boundary which resulted from the initial closure of the Panama Seaway.

Permian rugose corals of the world

Abstract Permian rugose corals underwent evolutionary episodes of assemblage changeover, biogeographical separation and extinction, which are closely related to geological events during this time. Two coral realms were recognized, the Tethyan Realm and the Cordilleran–Arctic–Uralian Realm. These are characterized by the families Kepingophyllidae and Waagenophyllidae during the Cisuralian, Waagenophyllidae in the Guadalupian and the subfamily Waagenophyllinae in the Lopingian, and the families Durhaminidae and Kleopatrinidae during the Cisuralian and major disappearance of colonial and dissepimented solitary rugose corals from the Guadalupian to the Lopingian, respectively. The development of these coral realms is controlled by the geographical barrier resulting from the Pangaea formation. According to the changes in the composition and diversity of the Permian rugose corals, a changeover event might have occurred at the end-Sakmarian and is characterized by the mixed Pennsylvanian and Permian faunas to typical Permian faunas, probably related to a global regression. In addition, three extinction events are present at the end-Kungurian, the end-Guadalupian and the end-Permian, which are respectively triggered by the northward movement of Pangaea, the Emeishan volcanic eruptions and subsequent global regression, and the global climate warming induced by the Siberian Traps eruption.

Threat of blast fishing on coral diversity in Peucang Island, Ujung Kulon National Park, Indonesia

Gumbira RWW, Rizkia F, Pribadi TDK, Hidayat MS. 2017. Threat of blast fishing on coral diversity in Peucang Island National Park, Indonesia. Ocean Life 1: 26-31. As a maritime country with high biodiversity, the health of Indonesian coral reefs is of high concern. Coral reef ecosystems are friable, and mortality occurs relatively quickly after disturbance, not only by nature but also by human activities such as fish bombing. Fish bombing is a big issue that has always threatened coral reefs, including in Peucang Island, part of Ujung Kulon National Park, a place that is protected by law to preserve its natural diversity. A study on coral coverage was conducted to observe the condition of corals and related biota in a coral reef ecosystem. Data was collected using Point Intercept Transect method in 2m and 8m depths. The results showed that coral coverage in 8-meter depth is only 44.02 percent of the live coral in 2-meter depth. The reduction in the value of Diversity Indices, Dominance Indices as well as the Evenness Index in all study sites led to low diversity, with no dominance by a particular species at any of the study sites. The results also showed that corals are well distributed in both depths. Over the past three years, the damage to corals in Peucang Island had generally increased by 0.7 percent due to fish bombing activities.

Coral reefs near the Eocene–Oligocene boundary in the northern Transylvanian Basin, Romania: Composition and paleoenvironmental interpretation

Eocene–Oligocene reefs have been reported in Europe largely from the circum‐Mediterranean region. In this paper, small coral reefs from the northwestern Transylvanian Basin (Romania) are described for the first time. They developed near the Eocene–Oligocene boundary, most probably during the Priabonian, and belong to northernmost outposts of the reef belt developed during this time in Europe. The studied sedimentary successions in Letca and Băbeni–Cuciulat (Sălaj County), up to 55 m thick, belong to the Cozla Formation. The reefs occur within a shallow‐water succession composed mostly of bedded limestones, dominated by bioclastic (coralline) packstones. Low‐relief (constratal) reefs, locally up to 10–15 m in thickness, are spaced cluster (matrix‐supported) reefs. Scleractinian corals are common but poorly diversified (10 species and 8 genera). Branching ramose colonies, branching low‐integrated phaceloid, and sheet‐like (foliaceous) corals dominate. Neither lateral zonation nor vertical succession of reefs was recognized. Corals co‐occur with encrusting and geniculate red algae, but they are of subordinate significance for a nonrigid reef framework. Branching corals baffled or trapped suspended carbonate mud that contributed to the reef growth and ongoing development of topographic relief. Associated fossils are of low to moderate diversity. A relatively low‐energy environment, moderate to high sedimentation rate, and increased turbidity are inferred from carbonate muddy and fine‐grained matrix, dominance of sediment‐resistant corals, their morphology, common occurrence in growth position, as well as low to moderate degree of bioerosion and encrustation. Transylvanian reefs in terms of poor coral diversity, matrix‐supported texture, and turbid‐water sedimentary setting show similarities with many coeval reefs from the circum‐Tethyan area.

Kondisi dan Keanekagaragaman Karang Batu di Perairan Sabang

<strong>Condition and Diversity of Stony Corals in Sabang Waters.</strong> Globally, coral reefs are facing a variety of threats, both natural and human activities. Coral reefs in the waters of Sabang in 2004 were hit by a tsunami and in 2010 an increase in sea surface temperatures caused a bleaching. These resulted in mass mortality of stony corals. This study aims to determine the current condition and the diversity of stony corals in Sabang waters. The study was conducted in May 2015 in ten stations spread over four islands, namely Pulau Weh, Pulau Rondo, Pulau Breueh, and Pulau Nasi Besar. The coral cover is calculated using Underwater Photo Transect (UPT) method. The images were analyzed using CPCe 4.1 program with 30 random points in each frame. The number of species and the number of coral colonies are calculated based on the number of species and coral colonies contained in the photo frames along the transect. Based on the results of the analysis, live coral cover ranged 22.45–58.60% with an average live coral cover of 41.99%. Throughout the transect, 148 species of stony corals from 37 genera and 15 families were discovered. In general, stony corals in Sabang waters are in a good condition, not different from the condition of coral reefs in 2005. Open waters have a positive impact on coral growth, especially for the genus Acropora.

Cembranoids of Soft Coral Sarcophyton from Acidified Coral Reef Environment at Shallow Water CO2 vents in Volcano Island, Banda Neira, Indonesia

Cembranoid content in soft coral is known as a chemotype that relate with genotype and environment. This research aimed to characterize the cembranoid Sarcophyton soft coral from the reef that acidified by CO2 volcanic vents (pHT 7.8) at Volcano Islands waters, Banda-Neira (Indonesia), as a means of predicting the future impact of ocean acidification to the genetic diversity of Sarcophyton soft coral. 30 random colonies were taken, combined, and extracted with ethanol. Cembranoid isolation and identification had been done by high performance liquid chromatography and spectrometry techniques. Results of the study found sarcophytol derivatives (sarcophytol A, 11,12-epoxy sarcophytol A, sarcophytol B, and sarcophytol M) as the only chemotype in the sample. This may suggest low genetic diversity in the observed Sarcophyton sample. Therefore, it may suggest that even soft coral is known to be resilient to future acidification pressures, the genetic diversity or the production of diverse cytotoxic metabolite may be hampered due to ocean acidification in future climate change adaptation.