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a Location of the Wakatobi Marine National Park in SE Sulawesi, Indonesia. b Study sites Sampela, Buoy 3, Pak Kasim’s and Ridge 1 of the islands of Kaledupa and Hoga, respectively
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Indonesian coral reefs are the epicenter of marine biodiversity, yet are under rapid anthropogenically induced decline. Therefore, ecological monitoring of high diversity taxa is paramount to facilitate effective management and conservation. This study presents an initial report from a comprehensive survey of shallow-water (0–15 m) gorgonian assemb...
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Coral reefs are marine ecosystems with one of the highest levels of biodiversity that provide valuable goods and services. Coral reefs are fragile ecosystem and highly vulnerable to overfishing, destructive fishing practices, pollution, and natural factors. Climate change is one of the natural factors that impacted coral reefs. Southeast Asian cora...
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... As passive suspension feeders, extracting nutrients from the water column, hydrodynamic environmental variables have significant influence on nutrient availability, in turn affecting multiple aspects of gorgonian biology, morphology, and distribution (Muzik and Wainwright 1977;Chang-Feng and Ming-Chao 1993;Al-Marayati and Edmunds 2018). For example, faster currents deliver larger quantities of nutrients to gorgonian colonies, enhancing feeding and growth rates (Rowley 2018). The ability to withstand high currents, however, varies among growth forms, and morphological adaptations have developed to allow colonies to benefit from increased nutrient supply. ...
... Although current speeds and water motion may be lower at greater depth, many gorgonians are found at higher abundances here and communities are often composed of larger species like fan or tree morphologies (Rodríguez-Lanetty et al. 2003;Quintanilla et al. 2019). This is often explained by the distinction between zooxanthellate or azooxanthellate species among gorgonians, as light availability at greater depths can restrict the distribution of some zooxanthellate species (Kinzie 1973;Fabricius and McCorry 2006;Haapkylä et al. 2007;Rowley 2018). ...
... The composition of the surrounding benthic community therefore can strongly influence the distribution and structure of gorgonian communities at a given location. Although many studies have examined patterns in gorgonian abundance and distribution and the influence of environmental variables, particularly current speeds, these are proportionally fewer in the Indo-Pacific and specifically the Great Barrier Reef (but see Rowley 2018;Kupfner Johnson and Hallock 2020). ...
Gorgonians are a diverse and conspicuous component of coral reef ecosystems, providing habitat structure that supports unique assemblages of fishes and invertebrates. Evaluating their overall importance as ecological engineers requires an understanding of their spatial patterns of distribution, abundance and assemblage composition, and the biophysical factors that drive these patterns. No baseline data are available on the spatial patterns of distribution of gorgonians for the Great Barrier Reef. In this study, we quantified the abundance, genera richness, and composition of gorgonian assemblages using video surveys at three depths (5, 10, and 15 m) at 16 locations at the Palm Islands, an inshore island group in the central Great Barrier Reef. We compared gorgonian abundance and genera richness between depths and assessed the role of benthic habitat in structuring gorgonian communities. We also conducted a preliminary investigation of the potential role of water currents in driving gorgonian spatial patterns in the Palm Islands, using in situ current meters. Gorgonian abundance and genera richness consistently increased with depth, although the magnitude of the depth effect varied among locations. Abundance increased with increasing percent cover of rubble and conversely declined with increasing cover of hard corals. The composition of gorgonian assemblages also varied among depths, with whip (Junceella, Viminella) and fan (Acanthogorgia, Anthogorgia, Annella) growth forms being dominant at depths of 5 and 10 m, and branching (Dichotella, Icilogorgia) and candelabrum (Ctenocella) forms being dominant at 15 m. The shallow gorgonian assemblage was associated with high coral cover, whilst the deeper assemblage was associated with high per cent cover of rubble, turf and/or macroalgae. This study highlighted that the abundance, diversity, and composition of gorgonian assemblages on coral reefs in the Palm Islands are determined by a range of biophysical factors linked to depth. Further work is required to isolate the primary drivers of these depth-related effects and evaluate their relative importance.
... They are a polyphyletic group of octocorals with a "skeletal axis or axial-like layer composed of some combination of calcite and the horn-like, proteinaceous material gorgonin" (McFadden et al. 2010); that shapes the three-dimensional biogenic habitats of the ocean supporting numerous animal assemblages and associations (e.g., Carvalho et al. 2014;Cúrdia et al. 2015). Additionally, their environmental responses (Rowley 2018(Rowley , 2018a, climate adaptability (Goulet et al. 2017), production of secondary metabolites (Van Alstyne & Paul 1992) and evolutionary history (Bilewitch et al. 2014) have been of worldwide interest. However, plasticity of morphological traits, limited taxonomic characters, and a profusion of inadequate original descriptions renders gorgonian identification a complex task (Fabricius & Alderslade 2001;Daly et al. 2007;Perez et al. 2016). ...
... Thomas & George (1987) just listed the species as did Venkataraman et al. (2004), while Kumar et al. ( , 2018 listed it and provided the figure of the colony with the elongate meshwork from Fernando et al. (2017) and Kumar et al. (2014a). Kumar et al. (2016: PY-P;2018a) just lists the species. ...
The descriptive taxonomic records of a total of 226 gorgonian species (Octocorallia: Alcyonacea) from Indian seas and neighbouring areas were surveyed and critically reviewed with the main aim of providing a more reliable checklist. The
published accounts comprise: species originally described from within the region: subsequent descriptive records of the taxa originally described from within the region; and subsequent descriptive records of species originally described from
outside of the region. The reviews include an attempt to assess the validity of all subsequent descriptive records, although in numerous cases the species have been assessed as unrecognisable from their type descriptions. Numerous new binomial combinations, some tentative, have been proposed. The assessment of the validity of a species record is expressed as an “Opinion” with supporting justification. Of the 226 species, there are 111 that were originally described from locations outside of Indian waters and have subsequently been described and recorded as occurring in the region. Of these, there are 9 species where we were unable to decide if the records are valid or not, 94 were assessed as invalid, 5 as possibly valid and 3 were considered valid. The survey highlights four major problems regarding the reliability of some more recently published taxonomic records for the region: the use of ‘predatory journals’; plagiarism; the use of manipulated imagery in more than one description; and taxonomic decision apparently based on expediency.
... In the context of the Coral Triangle, information on octocorals is still very poor (Pérez et al., 2016). Studies on octocorals in Indonesia (e.g., Janes, 2013;McFadden et al., 2014;Rowley, 2018), Malaysia (e.g., Mohammad et al., 2016), and Papua New Guinea (e.g., Tursch and Tursch, 1982;Mana, 2011) focused on establishing taxonomic inventories and information on the contribution of different taxa to benthic assemblages is lacking. In general, the lack of data on the abundance of different octocoral taxa in coral reef studies is common among nations in the Coral Triangle (e.g., Asian Development Bank, 2014). ...
Octocorals are relatively understudied than other coral reef organisms despite their ecological and economic values. The Philippines is known to have high marine biodiversity, but information on octocorals is lacking. This study investigated spatial and temporal variations in the assemblage of octocorals in selected reef sites in the West Philippine Sea (WPS)- the Kalayaan Island Group (i.e., Pag-asa, Sabina, Lawak, and Northeast Investigator) and Ulugan in 2017 and 2019. Results showed high octocoral taxonomic richness (at least 10 families) in the study sites. Mean percent octocoral cover in WPS was 5.35% SE ± 0.55, with Sabina having the highest octocoral cover in both years. Significant differences in octocoral cover were observed among sites in both years, but among-station differences were only observed in 2017. Octocoral assemblage also differed among sites in both years (ANOSIM: R > 0.5, p < 0.05), wherein different octocoral taxa dominated in different sites. In particular, variations were driven by high cover of holaxonians, nephtheids, and coelogorgiids in Sabina, and clavulariids, tubiporiids, and xeniids in Northeast Investigator in 2017. In 2019, significant variations were driven by high cover of helioporiids in Pag-asa, while Sabina had higher abundance of holaxonians, nephtheids, alcyoniids, and xeniids. Short-term temporal variation on octocoral cover in monitoring stations in Pag-asa was not observed (Kruskal-Wallis, p > 0.05), although the overall mean octocoral cover increased from 1.23% ± SE 0.47 in 2017 to 2.09% SE ± 0.37 in 2019. Further, there was no significant change in the octocoral assemblage in Pag-asa between years (ANOSIM, R = 0.11, p = 0.07). This study highlights high octocoral taxonomic richness in the WPS relative to other sites in the Indo-Pacific Region and provides baseline information on the octocoral assemblages, which can be useful for future ecological studies and marine biodiversity conservation efforts.
... Benthic diversity in the Wakatobi is high, with 396 species of hermatypic corals (Pet-Soede & Erdmann, 2003) and 90 gorgonian morphospecies (Rowley, 2018) recorded within the park, 141 sponge taxa reported from the reef considered in the present study (Rovellini et al., 2019) and many taxa of CCA, filamentous turfing algae, macroalgae and ascidians ( Figure 1B). A total of eight benthic categories were used to describe the substrate in the photographs (Table 1). ...
The availability of colonizable substrate is an important driver of the temporal dynamics of sessile invertebrates on coral reefs. Increased dominance of algae and, in some cases, sponges has been documented on many coral reefs around the world, but how these organisms benefit from non-colonized substrate on the reef is unclear. In this study, we described the temporal dynamics of benthic organisms on an Indonesian coral reef across two time periods between 2006 and 2017 (2006–2008 and 2014–2017), and investigated the effects of colonizable substrate on benthic cover of coral reef organisms at subsequent sampling events. In contrast with other Indonesian reefs where corals have been declining, corals were dominant and stable over time at this location (mean ± SE percentage cover 42.7 ± 1.9%). Percentage cover of turf algae and sponges showed larger interannual variability than corals and crustose coralline algae (CCA) ( P < 0.001), indicating that these groups are more dynamic over short temporal scales. Bare substrate was a good predictor of turf cover in the following year (mean effect 0.2, 95% CI: 0–0.4). Algal cover combined with bare space was a good predictor of CCA cover the following year generally, and of sponge cover the following year but only at one of the three sites. These results indicate that turf algae on some Indonesian reefs can rapidly occupy free space when this becomes available, and that other benthic groups are probably not limited by the availability of bare substrate, but may overgrow already fouled substrates.
... Marine habitats underpinned by 'ecosystem engineers', e.g. seagrass meadows, coral reefs, kelp beds, etc., have been widely used as model systems to study how environmental changes regulate the composition, structure and functioning of marine assemblages (Jankowski et al., 2015;Bartsch et al., 2016;Rowley, 2018;Tuya et al., 2018). Most studies have analysed variation across horizontal scales, for example linking patters of faunal diversity with habitat complexity (Friedlander and Parrish, 1998;Wernberg et al., 2011). ...
... Marine habitats underpinned by 'ecosystem engineers', e.g. seagrass meadows, coral reefs, kelp beds, etc., have been widely used as model systems to study how environmental changes regulate the composition, structure and functioning of marine assemblages (Jankowski et al., 2015;Bartsch et al., 2016;Rowley, 2018;Tuya et al., 2018). Most studies have analysed variation across horizontal scales, for example linking patters of faunal diversity with habitat complexity (Friedlander and Parrish, 1998;Wernberg et al., 2011). ...
Similar to altitudinal gradients in terrestrial habitats, subtidal habitats experience abrupt environmental gradients across depth. The objective of this study was to understand how variation with depth of environmental factors (water temperature, light availability, water motion and sedimentation) affected the structure (size and morphology) of rhodoliths and the abundances of attached floral and faunal epibionts in a rhodolith bed at Gran Canaria Island (central-eastern Atlantic). Specifically, sampling took place seasonally at three depth strata: 18, 25 and 40 m throughout two successive years. Depth affected the size and morphology of rhodoliths, with bigger and mainly spherical nodules at 25, relative to those at 18 and 40 m depth. Larger biomasses of attached (epiphytic) macroalgae were observed at 18 and 25 m than at 40 m. The presence of hydrozoans living over rhodoliths also changed with depth, including higher abundances at 25 m than at 40 and 18 m, respectively. Wave-induced turbulence in the upper depth layer, and light intensity and sedimentation, in the lower depth layer, are the main environmental drivers regulating the presence, structure and functioning of rhodolith habitats.
... Species accumulation curves of gorgonians and scleractinians were then compared. increased with depth a pattern that has been reported previously (Rowley 2018). Their high overall diversity may well be a consequence of a continuously dynamic environment (Connell 1978) at depth, particularly with regard to temperature. ...
The mesophotic coral ecosystems (MCEs) of the Senyavin Islands (Pohnpei Island, and neighboring atolls Ant and Pakin) in the Federated States of Micronesia have received little research attention until recent years. These vibrant, environmentally dynamic ecosystems harbor a reservoir of biodiversity, with species and interactions new to science. Depths of ≥90 m have up to 20 °C annual variance. A strong El Niño event in 2016 resulted in a bloom-forming cyanobacteria smothering the upper MCEs of Pohnpei (25–65 m). Conditions persisted into 2017 with extensive coral bleaching and reef degradation with associated smothering by bloom-forming cyanobacteria and algae in the shallows. The initial bloom signature of 2016 at depth may, therefore, serve as a projected indicator of shallow reef health. Of the 160 reef-building scleractinian corals reported, 28 spanned the full depth range (0–45 m). Differences in irradiance due to geomorphology, as well as reef health, determined the depth transition between two primary benthic groups: photosynthetic scleractinians and filter-feeding azooxanthellate gorgonians, 60 m on low-relief atoll reefs and 45 m at high-relief walls and degraded reefs. Of the 109 gorgonian corals reported, 19 spanned the full depth range (0–140 m) with 70 morphospecies specific to lower mesophotic depths. Similarly, fish assemblages partitioned between shallow and mesophotic depths, characterized by herbivores and planktivores, respectively. Continuously growing marine resource exploitation and terrestrial runoff are heavily influencing reef health. The MCEs of Pohnpei are, thus, unique, yet vulnerable to the exacerbating stresses of man.
... These values are consistent with previous studies reporting similar ranges (2.95-20.6 ind m −2 ) for octocoral densities recently estimated in the Caribbean (Privitera-Johnson et al., 2015), except for station 17 in Roncador that showed unusually higher density than those previously reported (68.5 ind m −2 ). Interestingly, Roncador mid-water reefs showed higher mean octocoral densities (see Supplementary Table 4) than those reported in many Caribbean regions (Etnoyer et al., 2010;Sánchez, 2016) and those (9 ind m −2 ) reported for SE Sulawesi assemblages (Rowley, 2018). It is widely known that habitat complexity significantly affects the assembly of benthic communities (Sánchez et al., 1997a) and in this study we see a dramatic decrease in habitat complexity through the measured rugosity index. ...
Coral reef decline persists as a global issue with ties to climate change and human footprint. The SeaFlower Biosphere reserve includes some of the most isolated oceanic coral reefs in the Southwestern Caribbean, which provide natural experiments to test global and/or basin-wide factors affecting coral reefs. In this study, we compared coral and other substrate cover (algae, cyanobacteria, and octocorals), along population densities of keystone urchin species from two atolls (Serrana and Roncador Banks), during 1995, 2003, and 2015/2016. We also surveyed benthic foraminifera as a water quality proxy for coral growth in the last period. A steady reduction in coral cover was clearly observed at Roncador’s lagoon, but not at Serrana’s reefs, with significant differences between 1995 and 2015/2016. Percent cover of fleshy algae decreased significantly also at Roncador between 1995 and 2003 but did not change notably from 1995 to 2016 at Serrana. However, both Banks exhibited a loss in crustose coralline algae from 2003 to 2015/2016. Likewise, a reduction in bottom complexity, measured as bottom rugosity, was evident between 1995 and 2003. Roncador Bank had unprecedented high octocoral densities, which increased almost threefold from 2003 to 2015. In contrast, urchin densities were low in Roncador; only Diadema antillarum increased from 2003 to 2016 in Serrana Bank. The Foraminifera in Reef Assessment and Monitoring (FORAM) Index (FI) in the two Banks was below the range expected for healthy coral reefs. Although both Banks follow a reduction in CCA and CA cover, Roncador Bank also faces an alarming decline in coral cover, urchins and bottom complexity (rugosity) in contrast to increases in octocoral densities and potential loss of resilience and eutrophication suggested by the FI index. These unexpected findings led us to consider and discuss potential outcomes, where these reefs deteriorate (i.e., erode and drown) providing ideal conditions for octocoral growth. Hence, it is of utmost urgency to start monitoring reef budgets, octocorals and nutrient sources.
... El crecimiento acelerado de la población humana en áreas costeras ha provocado el incremento de nutrientes en los ecosistemas marinos costeros (Fabricius 2011b). El enriquecimiento de nutrientes en los arrecifes de coral ha traído como consecuencia una disminución en la abundancia, cobertura, diversidad y riqueza de especies de octocorales (Yeung et al. 2014;Rowley 2018), así como cambios fi siológicos en los corales pétreos y afectaciones en la estructura de la comunidad arrecifal (Fabricius et al. 2012;Baum et al. 2015). La región noroccidental de Cuba no está exenta de esta problemática, ya que los arrecifes del litoral de La Habana son afectados por la contaminación orgánica proveniente de las descargas residuales a través de ríos, difusores submarinos y vertimientos costeros. ...
La contaminación orgánica en el litoral de La Habana está afectando las asociaciones de octocorales, y poco se conoce su efecto en la tasa de crecimiento (TC). Se empleó un transecto de banda fijo (250 x 2 m) para localizar las colonias. La TC de Eunicea fl exuosa y Plexaura kuekenthali fue significativamente mayor en el arrecife con más contaminación orgánica (3,6 cm/año y 4,1 cm/año, respectivamente) vs. sitios de referencia, lo que parece estar relacionado con su heterotrofía.
Organic pollution in the Havana coastline is affecting octocorals assemblages, and little is known about its effect on the growth rate (GR). A fi xed belt transect (250 x 2 m) was used to locate the colonies. The GR of Eunicea fl exuosa and Plexaura kuekenthali was signifi cantly higher in the reef with more organic pollution (3,6 cm/año y 4,1 cm/año, respectively) vs. reference sites, which seems to be related to their heterotrophy.
Gorgonian is one of marine invertebrates that is still underexplored as a source of bioactive compounds. This study aimed to discover the biological properties of Astrogorgia sp. and its phytochemical content. A consecutive extraction method using n -hexane, ethyl acetate and methanol was conducted to obtain secondary metabolites from the sample. Antimicrobial assay was performed against ESBL E. coli , MRSA, C. albicans , and M. furfur ; cytotoxicity against P388 Murine Leukaemia Cancer Cells, antioxidant was tested using DPPH method. The consecutive extraction method gave yield (%) as follows: 0.21 ± 0.22 from n -hexane; 0.67 ± 0.17 from acetyl acetate; and 1.20 ± 0.50 from methanol. All fractions gave positive results on antibacterial assay against all pathogens while only gave antifungal activity against C. albicans . Methanol fraction had the highest antioxidant activity, while n -hexane fraction showed the best cytotoxicity.
