Acropora Research Papers - Academia.edu (original) (raw)

As in the tropical Atlantic, Acropora populations in the southern Persian/Arabian Gulf plummeted within two decades after having been ecosystem engineers on most wave-exposed reefs since the Pleistocene. Since 1996/1998 live coral cover in the Gulf declined by over 90% in many areas, primarily due to bleaching and diseases
caused by rising temperatures. In the formerly dominant table-coral species A. downingi, population dynamics corresponding to disturbance regimes was quantified in three transition matrices (lower disturbance pre-1996; moderate disturbance from 1998 to 2010 and 2013 to 2017, disturbed in 1996/1998, 2010/11/12, 2017). Increased disturbance frequency and severity caused progressive reduction in coral size, cover, and population fecundity. Small size-classes were bolstered more
by partial colony mortality than sexual recruitment. Some large corals had a size refuge and resisted die-back but were also lost with increasing disturbance. Matrix
and biophysical larval flow models suggested one metapopulation. Southern, Arabian, populations could be connected to northern, Iranian, populations but this connectivity was lost under assumptions of pelagic larval duration at rising temperatures shortened to a third. Then, the metapopulation disintegrated into isolated populations. Connectivity required to avoid extinctions increased exponentially with disturbance frequency and correlation of disturbances across the metapopulation.
Populations became unsustainable at eight disturbances in 15 years, when even highest theoretical recruitment no longer compensated mortality. This lethal disturbance frequency was 3-fold that of the moderately disturbed monitoring period and 4-fold of the preceding low-disturbance period—suggesting ongoing shortening of the disturbance-free period. Observed population collapse and environmental changes in the Gulf suggest that A. downingi is heading toward at least functional extinction mainly due to increasingly frequent temperature-induced mortality events, clearly linked to climate change

- by
- •
- Coral Reef Ecology, Coral Bleaching, Arabian/Persian Gulf Studies, Acropora

A recent survey on coral diseases was conducted using manta tow and modified point estimate randomly done at a single point in time by snorkelling along reef sites at Piapi and Bantayan, Dumaguete City. Coral disease assessment was done by underwater photography. The diseases of corals and the characteristic of coral species affected was identified using related references. These were confirmed by subject specialists at Silliman University, Dumaguete City. The findings during dry and wet seasons in 2015 showed that there were 2 diseases: White Band Disease type II (WBD II) found in Acropora and tumor/Growth Anomaly (GA) found in Porites.

- by Anggreini Rupidara
- •
- Coral Diseases, Acropora, Porites, Coral Reef Assessment and Monitoring

Terumbu karang merupakan habitat dari banyak biota laut seperti ikan dan udang. Penangkapan biota laut menggunakan cara dan bahan yang berbahaya seperti bom dan pukat harimau menyebabkan rusaknya terumbu karang secara masif. Penelitian ini bertujuan untuk mengetahui cara penanaman kembali (replantasi) terumbu karang di kawasan Sea Farming, Pulau Panggang, Kepulauan Seribu, DKI Jakarta. Metode yang digunakan dalam penelitian ini adalah metode transplantasi, yaitu dengan memotong karang hidup lalu ditanam di tempat lain yang mengalami kerusakan, tujuannya untuk pemulihan atau pembentukan terumbu karang alami. Media yang digunakan ada 2, yaitu karang mati (rock fell) dan rak. Jenis karang yang digunakan dalam penelitian terdapat sekitar 4 jenis yang berasal dari marga Acropora. Pengukuran kualitas lingkungan dilakukan menggunakan water checker dan DO meter dengan hasil rata-rata Intensitas cahaya 23965 Lux ; suhu 29,6oC ; DO 6,04 mg/L dan salinitas 32,1 ppt.

- by Dhita Gustiani
- •
- Marine Biology, Conservation Biology, Marine Ecology, Biology

Despite the ecological significance of the relationship between reef-building corals and intracellular photosynthetic dinoflagellates of the genus Symbiodinium, very little is known about the molecular mechanisms involved in its establishment. Indeed, microarray-based analyses point to the conclusion that host gene expression is largely or completely unresponsive during the establishment of symbiosis with a competent strain of Symbiodinium. In the present study, the use of Illumina RNA-Seq technology allowed detection of a transient period of differential expression involving a small number of genes (1073 transcripts; <3% of the transcriptome) 4 h after the exposure of Acropora digitifera planulae to a competent strain of Symbiodinium (a clade B strain). This phenomenon has not previously been detected as a consequence of both the lower sensitivity of the microarray approaches used and the sampling times used. The results indicate that complex changes occur, including transient suppression of mitochondrial metabolism and protein synthesis, but are also consistent with the hypothesis that the symbiosome is a phagosome that has undergone early arrest, raising the possibility of common mechanisms in the symbiotic interactions of corals and symbiotic sea anemones with their endosymbionts.

- by Amin Mohamed
- •
- Transcriptomics, Symbiosis, Coral Reefs, Symbiodinium

The role of corallivory is becoming increasingly recognised as an important factor in coral health at a time when coral reefs
around the world face a number of other stressors. The polyclad flatworm, Amakusaplana acroporae, is a voracious predator
of Indo-Pacific acroporid corals in captivity, and its inadvertent introduction into aquaria has lead to the death of entire coral
colonies. While this flatworm has been a pest to the coral aquaculture community for over a decade, it has only been found
in aquaria and has never been described from the wild. Understanding its biology and ecology in its natural environment is
crucial for identifying viable biological controls for more successful rearing of Acropora colonies in aquaria, and for our
understanding of what biotic interactions are important to coral growth and fitness on reefs. Using morphological,
histological and molecular techniques we determine that a polyclad found on Acropora valida from Lizard Island, Australia is
A. acroporae. The presence of extracellular Symbiodinium in the gut and parenchyma and spirocysts in the gut indicates that
it is a corallivore in the wild. The examination of a size-range of individuals shows maturation of the sexual apparatus and
increases in the number of eyes with increased body length. Conservative estimates of abundance show that A. acroporae
occurred on 7 of the 10 coral colonies collected, with an average of 2.660.65 (mean 6SE) animals per colony. This
represents the first report of A. acroporae in the wild, and sets the stage for future studies of A. acroporae ecology and life
history in its natural habitat.

- by Jessica Stella
- •
- Invertebrate Biology, Coral, Acropora, AEFW

Current seawater temperatures around the northeastern Arabian Peninsula resemble future global forecasts as temperatures > 35 °C are commonly observed in summer. To provide a more fundamental aim of understanding the structure of wild populations in extreme environmental conditions, we conducted a population genetic study of a widespread, regional endemic table coral species, Acropora downingi, across the northeastern Arabian Peninsula. A total of 63 samples were collected in the southern Arabian/Persian Gulf (Abu Dhabi and Qatar) and the Sea of Oman (northeastern Oman). Using RAD-seq techniques, we described the population structure of A. downingi across the study area. Pairwise G’st and distance-based analyses using neutral markers displayed two distinct genetic clusters: one represented by Arabian/Persian Gulf individuals, and the other by Sea of Oman individuals. Nevertheless, a model-based method applied to the genetic data suggested a panmictic population encompassing both ...

- by Felipe Torquato
- •
- Earth Sciences, Climate Change, Adaptation to Climate Change, Population Genetics

- by Peter R Møller
- •
- Earth Sciences, Climate Change, Adaptation to Climate Change, Population Genetics
- by Filipina Sotto
- •
- Marine Protected Areas, Coral Restoration, Acropora, Artificial Reef

Here, we report the successful cross-species amplification of previously published acroporid microsatellite markers in the coral Acropora austera from the south-western Indian Ocean. This fast-growing species is a major reef-building coral on South African reefs; however, it is the most damaged coral by scuba diving activity, and is known to be very susceptible to coral bleaching. Neither genetic information nor symbiont-free host tissue was available to develop novel microsatellite markers for this species. Cross-species amplification of previously published microsatellite markers was considered as an alternative to overcome these problems. Of the 21 microsatellite markers tested, 6 were reliably amplified, scored, and found to contain polymorphic loci (3-15 alleles). Although microsatellite sequences are believed to be scarce in the Acropora genome because of its small size, the results of this study and previous research indicate that the microsatellite sequences are well conserved across Acropora species. A detailed screening process identified and quantified the sources of error and bias in the application of these markers (e.g., allele scoring error, failure rates, frequency of null alleles), and may be accounted for in the study of the contemporary gene flow of A. austera in the south-western
Indian Ocean.

- by Phanor H Montoya-Maya
- •
- Coral Reefs, Molecular Markers, Western Indian Ocean, Coral Reef Genetics

Chronic coral reef degradation has been characterized by a significant decline in the population abundance and live tissue cover of scleractinian corals across the wider Caribbean. Acropora cervicornis is among the species whose populations have suffered an unprecedented collapse throughout the region. This species, which once dominated the shallow-water reef communities, is susceptible to a wide range of stressors, resulting in a general lack of recovery following disturbances. A. cervicornis is a critical contributor to the structure, function, and resilience of Caribbean coral reefs. Therefore, it is essential to identify the factors that influence their demographic and population performance. Diseases are one of the factors that are compromising the recovery of coral populations. In this chapter, we use size-based population matrix models to evaluate the population-level effect of a Shut Down Reaction Disease (SDR) outbreak, one of the less-understood diseases affecting this coral. The model was parameterized by following the fate of 105 colonies for 2 years at Tamarindo reef in Culebra, Puerto Rico. SDR, which affected 78% of the population, led to a rapid decline in colony abundance. The estimated population growth rate (λ) for the diseased population was more than six times lower than would be expected for a population at equilibrium. It was found that colonies in the smaller size class (≤100cm total linear length) were more likely to get infected and succumbing to the disease than larger colonies. Model simulations indicate that: (1) under the estimated λ, the population would reach extinction in 5 years; (2) an SDR outbreak as intense as the one observed in this study can lead to a notable decline in stochastic λs even when relatively rare (i.e. 10% probability of occurring); and (3) disease incidence as low as 5% can cause the population to lose its ecological functionality (e.g., reach a pseudo-extinction level of 10% of the initial population size) 33 years before disappearing. SDR and probably any other similarly virulent disease could thus be a major driver of local extinction events of A. cervicornis.

- by Edwin A. Hernández-Delgado
- •
- Marine Biology, Biology, Ecology, Medicine

Population declines of staghorn coral (Acropora cervicornis) and elkhorn coral (A. palmata) are often-cited examples of Caribbean reef change since the 1970s, due, in part, to disease and localized effects from storms and predation. Both corals were listed as threatened on the U.S. Endangered Species List based upon range-wide decline and poor recovery. A spatially intensive survey undertaken in the Florida Keys of Acropora corals quantified habitat distribution, colony abundance, size, and condition at 235 sites spanning over 200 km in 2007. A two-stage stratified sampling design using belt transects incorporated cross-shelf habitats and no-fishing management zones from < 1 m to 15 m depth. A. cervicornis was widely distributed among sites and habitats and was particularly abundant on patch reefs, with up to 1.22 colonies/m 2 and surface area coverage of 2%. A. palmata was abundant on shallow spur and groove reefs, with up to 1.25 colonies/m 2 and surface area coverage of 25%. A...

- by Mark Chiappone
- •
- Biology, Endangered Species, Population, Key words

Reef-building corals living in extreme environments can provide insight into the negative effects of future climate scenarios. In hot environments, coral communities experience disproportionate thermal stress as they live very near or at their upper thermal limits. This results in a high frequency of bleaching episodes, but it is unknown whether temperature-driven outbreaks of coral disease follow a similar trajectory. Here we tracked outbreaks of a white-syndrome (WS) disease over three years in the hottest region inhabited by reef-building corals, the southern Persian Gulf. From 2014 to 2016, WS affected 10 of the 16 scleractinian genera recorded at inshore and offshore sites. Intra-and inter-specific transmission of lesions was frequently observed, indicative of a single contagious disease infecting multiple coral taxa. Colonies of Acropora were the most susceptible to WS disease and were more than twice as likely to experience lesions than any other genera. Prevalence reached 42% of Acropora colonies and lesions progressed at an average rate of 1 mm day-1. Platygyra colonies were the second most susceptible to WS disease, where prevalence reached 33% and lesions progressed at 0.3 mm day-1. Affected colonies of both of these genera suffered considerable partial mortality that was not recovered between years, promoting the fragmentation of larger colonies into smaller size classes. Across the 3 years of our study, the onset of WS outbreaks occurred early in summer and prevalence increased exponentially with cumulative heat exposure (coral community r 2 = 0.55, Acropora r 2 = 0.72, Platygyra r 2 = 0.75). Peak levels of community-wide prevalence occurred in August (10% of all coral colonies) to September (14%) when preceding 4-week and 8-week average temperatures exceeded 34.5°C and 34°C, respectively. Outbreaks ceased following the return of cooler temperatures with prevalence remaining below 0.5% between December and June. Levels of bleaching remained relatively low (\ 5% prevalence), despite exposure to daily temperatures C 35°C each summer. These findings demonstrate that thermal stress on coral reefs does not always manifest as coral bleaching and diseases can present as a primary sign of thermal stress. Consequently, temperature-driven outbreaks of coral disease are expected to become more widespread as climate warming pushes corals to be living increasingly closer to their upper thermal limits.

- by John A Burt
- •
- Coral Reefs, Arabian Gulf, Persian Gulf, Coral Reef Ecology

Acropora is the most biologically diverse group of reef-building coral, and its richness peaks at the Indo-Malay-Philippine Archipelago, the centre of global coral reef biodiversity. In this paper, we describe the species richness of Acropora fauna of North Borneo, East Malaysia, based on review of literature and as corroborated by voucher specimens. Eighty-three species of Acropora are reported here; four species are literature based and 79 are supported by voucher specimens that were subsequently photographed. New records for North Borneo were recorded for 12 species, including Acropora suharsonoi Wallace 1994 that was previously thought to be confined to a few islands along Lombok Strait, Indonesia. The diversity of Acropora in North Borneo is comparable to that of Indonesia and the Philippines, despite the area's smaller reef areas. This further reinforces its inclusion as part the global hotspot of coral biodiversity.

- by Muhammad Ali Syed Hussein
- •
- Evolutionary Biology, Zoology, Malaysia, Coral Reefs

Coral reefs provide numerous ecosystem services and host more than 20% of marine biodiversity. However, the impact of recreational SCUBA diving on coral reefs is not often quantified in marine protected areas. We quantified the impact of divers on coral reefs in five sites within the National Park Reefs of Puerto Morelos, Mexico during high and low tourist seasons. We recorded the number and types of impacts on coral reefs done by divers during 30 minutes and the occurrence of endangered Acropora spp. The impacts most frequently recorded were "touching coral" and "creating sediment clouds" in the shallowest site, during the low season. A warning system was adopted by the Park based on the results. Making this information available for decision-making is crucial for ensuring the sustainable management of tourism, contributes to the conservation of fragile coral reef ecosystems, and ensures the sustianbility of livelihoods that rely on them.

- by Gabriel Sanchez Rivera
- •
- Marine Protected Areas, Sustainable Tourism, Acropora, Riviera Maya

In this study we tested the cross-amplification of 33 microsatellite loci previously developed for two closely related Neotropical orchid genera (Epidendrum and Laelia). A set of ten loci were polymorphic across five examined species (20 individuals each) with 2 to 15 alleles per locus. The mean expected and observed heterozygosity (average across species) ranged from 0.34 to 0.82 and from 0.27 to 0.85, respectively. In addition we tested all loci in 35 species representative of the genus Epidendrum. Of these, 26 loci showed successful amplification. Cross-application of these loci represent a potential source of co-dominant markers for evolutionary, ecological and conservation studies in this important orchid genus.

- by Fábio Pinheiro
- •
- Genetics, Molecular Biology, Polymorphism, Population Genetics
- by Fabio Pinheiro
- •
- Genetics, Molecular Biology, Polymorphism, Population Genetics

- by ximena arvizu
- •
- Ecotourism, Marine Protected Areas, Sustainable Tourism, Tourism

This study reports on the cross-species amplification of 23 microsatellite markers previously developed for Theobroma cacao L. (Sterculiaceae), source of chocolate in three economically important Amazonian species of Theobroma (T. grandiflorum, T. subincanum, T. sylvestre). Thirteen of the 23 microsatellite loci tested were polymorphic across the three species at 2–13 alleles per locus. The observed heterozygosity per locus varied from 0.18 to 0.84 and expected heterozygosity ranged from 0.28 to 0.87. The high level of transferability and genetic information content of these microsatellite loci indicate their usefulness for population genetic, mating system and breeding studies of these economically important Amazonian fruit trees.

- by Rogério Gribel
- •
- Genetics, Molecular Biology, Polymorphism, Population Genetics
- by Randall Kosaki
- •
- Hawaii, Acropora