Coral assemblages and physico-chemical characteristics of the Whitsunday Islands: evidence of recent community changes

1999 ◽  
Vol 50 (5) ◽  
pp. 427 ◽  
Author(s):  
R. van Woesik ◽  
T. Tomascik ◽  
S. Blake

Benthic communities were assessed and 22 environmental variables were monitored at seven leeward localities (L1ŒL7) in the Whitsunday Islands, Queensland, Australia. L1 was near the Proserpine and O’Connell river mouths and L7 ~80 km north of the river mouths. Distinct physico Œchemical and biological gradients were evident. Sparse scleractinian coral communities, dominated by faviids, Montipora spp. and encrusting Porites colonies, were present at L1, L2 and L3, whereas diverse reef-building communities, dominated by Acropora spp., were more common at and beyond L4. The number of coral recruits (age <6 months) did not differ significantly among localities, suggesting that coral recruitment was near random and that the environment shapes the adult community from those recruits. The study demonstrates strong negative relationships between chlorophyll a and the following: percentage coral cover, coral species richness and coral abundance. The reef-building capacities of the coral communities and the extent of Holocene reef development were inconsistent at L2 and L3, which is interpreted as a sign of anthropogenic effects.

2021 ◽  
Author(s):  
Lorenzo Alvarez-Filip ◽  
F. González-Barrios ◽  
Esmeralda Pérez-Cervantes ◽  
Ana Molina-Hernandez ◽  
Nuria Estrada-Saldívar

Abstract Diseases are major drivers of the deterioration of coral reefs, linked to major declines in coral abundance, reef functionality, and reef-related ecosystems services1-3. An outbreak of a new disease is currently rampaging through the populations of the remaining reef-building corals across the Caribbean region. The outbreak was first reported in Florida in 2014 and reached the northern Mesoamerican reef by summer 2018, where it spread across the ~ 450-km reef system only in a few months4. Rapid infection was generalized across all sites and mortality rates ranged from 94% to < 10% among the 21 afflicted coral species. This single event further modified the coral communities across the region by increasing the relative dominance of weedy corals and reducing reef functionality, both in terms of functional diversity and calcium carbonate production. This emergent disease is likely to become the most lethal disturbance ever recorded in the Caribbean, and it will likely result in the onset of a new functional regime where key reef-building and complex branching acroporids (a genus apparently unaffected) will once again become conspicuous structural features in reef systems with yet even lower levels of physical functionality.


1997 ◽  
Vol 45 (1-2) ◽  
pp. 35-43 ◽  
Author(s):  
Roberto Villaça ◽  
Fábio B. Pitombo

The benthic communities of fringing and mushroom-shaped shallow-water reefs of the Abrolhos region (southern coast of Bahia) were surveyed. Line transects were used to estimate coral and algal percentage cover. Mussismilia braziliensis is the most conspicuous coral species in the majority of the communities surveyed, but turf algal make up the dominant cover in all but one studied reef. In general, communities on mushroom-shaped reefs have higher diversity and higher coral cover than on fringing reefs. For both reef morphologies, the coral to alga cover ratio does. not show marked differences between annual surveys, despite the high productivity characteristic of the dominant algal species.


1995 ◽  
Vol 46 (2) ◽  
pp. 457 ◽  
Author(s):  
VJ Harriott ◽  
PL Harrison ◽  
SA Banks

Lord Howe Island (31�33′S, 159�05′E) is surrounded by the southern-most coral reefs in the Pacific Ocean. The status of the benthic communities at Lord Howe Island was quantified in 1992-93 using replicated video-transects at 20 sites in the shallow reefal area (<20 m depth). The cover of hard coral was comparable with coral cover on some tropical reefs, ranging from less than 10% at some reef flat sites to greater than 40% cover at two seaward beach sites. The process of reef formation is apparently slow, and accretion of limestone is localized. A total of 59 scleractinian coral species were recorded during this study (including 19 new records), bringing the total number recorded at Lord Howe Island to 83. The coral communities contain a unique association of tropical species at their southern limits of distribution, and subtropical species which are rare or absent from the Great Barrier Reef. Many of the species that have been recorded from Lord Howe Island are rare, and may have resulted from chance recruitment of only a few larvae. There have been few major changes in the coral communities at Lord Howe Island in the past 16 years. At two inshore sites there was an apparent reduction in hard coral cover in the 1980s.


Author(s):  
Paul L.A. Erftemeijer ◽  
Mary Hagedorn ◽  
Michael Laterveer ◽  
Jamie Craggs ◽  
James R. Guest

The effect of increased levels of suspended sediment on fertilization success in the scleractinian coral Pectinia lactuca was investigated in a laboratory experiment following a mass coral spawning event on reefs off Singapore. Egg–sperm bundles were collected from tank-spawned coral colonies collected from the field several days prior to the anticipated mass spawning. Eggs and sperm from each colony were separated and distributed systematically across replicated treatments (N = 9) with three concentrations of fine suspended sediment. Spawning and embryo development in Pectinia lactuca followed a pattern similar to other scleractinian coral species. There was a significant effect of increased suspended sediment concentration on fertilization success (P < 0.05). Both high- (169 mg l−1) and medium- (43 mg l−1) suspended sediment treatments decreased fertilization success compared to controls. These results imply that increased turbidity levels (whether chronic, such as in the waters around Singapore, or short-term, caused by a dredging operation)—when coinciding with the coral spawning season—may affect the reproductive success of corals and compromise coral recruitment and recovery of degraded reefs.


Author(s):  
Khodzori Fikri Akmal ◽  
Saad Shahbudin

Monitoring coral health status is important for effective reef ecosystem management. The present study aimed to determine the coral condition and distribution at twenty sites around Tioman Island Marine Park (TIMP), Malaysia. The Coral Video Transect (CVT) method was used to survey coral, and the Coral Point Count with Excel extension (CPCe) software was used to analyse images for identification and coral coverage measurement. The findings indicate that TIMP reefs had a mean live coral cover of 48.0% ± 0.7, suggesting they were in ‘fair’ coral condition. A total of 254 species, spanning 61 genera and 15 families of scleractinian coral were identified across all reef sites. Following the recent taxonomic classification, coral surveys and past studies revealed 355 species from 67 genera and 15 families of scleractinian coral with additional 30 new species records for TIMP, and 15 for the east coast of Peninsular Malaysia. Overall, 29 identified scleractinian species are considered rare, 86 vulnerable, and 3 are endangered. Current data also recorded 77 genera from 24 families of hard and soft corals with Acropora, Montipora and Porites predominantly found in reef assemblages. Overall, it can be concluded that the extensive coastal development and widespread tourism activities may have influenced the variations in coral condition and distribution in this Marine Park.


2010 ◽  
Vol 2 ◽  
pp. 95 ◽  
Author(s):  
Carlos Jiménez ◽  
Giovanni Bassey ◽  
Álvaro Segura ◽  
Jorge Cortés

In the seasonal upwelling region of Gulf of Papagayo (Northern Pacific coast of Costa Rica), we evaluated and described two previously poorly known coral habitats, Punta Cacique and Bahía Guacamaya. Both localities differed in the extent of the frame-building coral communities and their composition. While Bahía Guacamaya and Punta Cacique had a similar number of coral species (16), live coral cover percent was higher in the coral reefs (ca. 50% vs. 90%) and coral communities (ca. 40% vs. 50%) of the latter. At both localities, branching species (Pocillopora spp.) contributed more as a group to the live coral cover than massive and encrusting corals. Bahía Guacamaya has the largest colonies found so far of two coral species (Pocillopora eydouxi and Pocillopora meandrina) with a limited distribution in Costa Rica. Using long-term records of environmental data, we characterized the seasonality of the upwelling and the dry and rainy seasons that partially explained the low suspension sediment loads and fresh water discharge into Papagayo’s coral habitats. The results of our study are important due to the rapid development of the coastal zone of Papagayo and because only a fraction of the littoral has been systematically surveyed. Therefore, we call for more studies that aim to produce baseline data of coral habitats in the area.En la región de afloramiento estacional del Golfo de Papagayo (Costa Rica), se evaluaron dos ambientes coralinos que nunca antes habían sido estudiados: Punta Cacique y Bahía Guacamaya. En ambas localidades, la extensión y la composición de las comunidades coralinas constructoras de la estructura arrecifal fueron diferentes. En tanto que el número de especies coralinas (16) fue similar en ambas localidades, el porcentaje de cobertura de coral vivo fue mayor en los arrecifes (apróximamente 50% vs. 90%) y las comunidades (aproximadamente 40% vs. 50%) coralinas de Punta Cacique. En ambos sitios, las especies de corales ramificados (Pocillopora spp.) como grupo contribuyeron más a la cobertura de coral vivo que otras formas (masivas e incrustantes).  La Bahía Guacamaya tiene las colonias más grandes encontradas hasta el momento en Costa Rica de dos especies de distribución limitada (Pocillopora eydouxi y Pocillopora meandrina). Se utilizaron series temporales extensas de datos ambientales para caracterizar la estacionalidad del afloramiento y la estación seca y la lluviosa. Estos dos factores explican parcialmente la poca sedimentación y descarga de agua dulce en los ambientes coralinos de Papagayo. Los resultados de nuestro estudio son importantes dado que apenas una pequeña fracción de la costa de Papagayo ha sido estudiada sistemáticamente a pesar del rápido desarrollo costero que ocurre en el área. Por lo tanto, resaltamos la necesidad de realizar más estudios, con el fin de obtener datos de línea base de los ambientes coralinos del área.


2011 ◽  
Vol 3 ◽  
pp. 51
Author(s):  
Hansel Caballero ◽  
Pedro M. Alcolado

Se evaluó la condición de la barrera de coral de los Bajos de Sancho Pardo (NW Cuba), área alejada de acciones antrópicas (excepto sobrepesca), pero que ha sufrido un período de frecuencia de huracanes, brotes de enfermedades y eventos de blanqueamiento de corales. En agosto del 2010 se aplicó la metodología de muestreo AGRRA en comunidades de corales de tres estaciones en las crestas, tres en las zonas traseras y 15 en el frente de arrecifes. Se identificaron 32 especies de corales, considerando solo colonias mayores de 10 cm de diámetro máximo. Los indicadores biológicos analizados sugieren cierta heterogeneidad en lascondiciones medioambientales y diferentes grados de resiliencia de los corales ante los disturbios naturales. El cubrimiento vivo medio de coral fue de 23% en las crestas, 27% en las zonas traseras y 9% en los arrecifes frontales. La densidad media lineal de corales fue de 8 colonias/10 m en las crestas, 11 colonias/10 m en las zonas traseras y 5 colonias/10 m en los arrecifes frontales. Se observó mortalidad reciente por enfermedades activas. La mortalidad antigua fue mayor en las zonas traseras y en las crestas, a causa aparentementede la mayor influencia de los huracanes por la menor profundidad. Los arrecifes estuvieron perturbados por cubrimiento importante de algas carnosas supuestamente por un insuficiente nivel de herbivorismo. ABSTRACT The condition of the barrier reef in Bajos de Sancho Pardo (NW Cuba) was assessed. This area is located far from anthropogenic disturbances (except overfishing) and has suffered a period of frequent hurricanes, coral disease outbreaks, and coral bleaching events. In August 2010, the AGRRA sampling methodology was applied to 21 coral communities;three crest stations, three rear zones, and 15 fore reef stations. Thirty-two coral species were identified, considering only colonies larger than 10 cm maximum diameter. The biological indicators analyzed suggest some degree of heterogeneity of environmental conditions and different levels of coral resiliency to natural disturbances. Average live coral cover was 23% on reef crests, 27% on back reefs and 9% on fore reefs. Average coral linear density was 8 colonies/10 m on reef crests, 11 colonies/10 m on back reefs and 5 colonies/10 m on fore reefs. Recent mortality was observed resulting from active diseases. Old mortality was higher in back reefs and reef crests, apparently due to the higher influence of hurricanes due to their shallow depths. Reefs were disturbed by a significant fleshy algae cover provably due to low levels of herbivory.


1995 ◽  
Vol 46 (8) ◽  
pp. 1137 ◽  
Author(s):  
SA Banks ◽  
VJ Harriott

The Gneering Shoals and Mudjimba Island are coastal rocky-reef communities approximately 250 km south of the Great Barrier Reef. Ten sites from 700 m to 12 km offshore were investigated with the use of video-transects to determine percentage cover of benthic organisms. The marine benthic communities were dominated by hard corals, soft corals and turf algae. Three community types were identified: (1) offshore communities, (2) island-associated communities, and (3) a nearshore algae-dominated community. Inshore sites were dominated by flat encrusting hard corals, whereas offshore sites were dominated by foliose and plating hard corals, particularly Acropora solitaryensis and Turbinaria spp. There was a notable scarcity of branching species, particularly from the Family Acroporidae. Seventy-seven species of scleractinian coral, representing 30 genera in 11 families, have been recorded from the Gneering Shoals region. The Gneering Shoals had low coral species richness relative to the southern Great Barrier Reef (244 species) and Flinders Reef, 50 km to the south-east (118 species). Possible explanations for the relatively low coral species richness in the Gneering Shoals region include the physical attributes of the site and the hypothesized failure of the East Australian Current to be a major influence on the region.


2018 ◽  
Vol 69 (6) ◽  
pp. 997 ◽  
Author(s):  
Erin E. Easton ◽  
Carlos F. Gaymer ◽  
Alan M. Friedlander ◽  
James J. Herlan

The Easter Island ecoregion includes Rapa Nui (Easter Island; RN), with a human population of ~5600, and the uninhabited Salas y Gómez (SyG). Although the culture and terrestrial ecology of RN have been well studied, we know little about the marine environment of these islands, particularly the interplay among herbivores, algae, and corals, and how coral reef communities differ between islands, by wave energy exposure, and between depths. To address the potential roles of herbivores, wave-energy exposure, and depth on the sessile benthic communities, we examined herbivorous fish biomass, sea urchin (Diadema savignyi) density, and algal and coral cover to identify patterns and relationships among these groups. We found significant differences between islands. For example, turf and macroalgae were nearly absent from SyG, whereas D. savignyi density and Kyphosus sandwicensis biomass were ~28- and ~3-fold greater respectively at SyG. Benthic cover of coral and algae and density of D. savignyi significantly differed among levels of wave exposure, especially between wave-protected stations and semi-exposed and exposed stations. Likewise, community structure significantly differed at protected stations. Concordant patterns between herbivores and algae were observed. Therefore, herbivores and wave energy likely play important roles in structuring these benthic communities, especially for algal groups.


2014 ◽  
Author(s):  
Sarah W Davies ◽  
Eli Meyer ◽  
Sarah M Guermond ◽  
Mikhail V Matz

Caribbean coral reefs have deteriorated substantially over the past 30 years, which is broadly attributable to the effects of global climate change. In the same time, Indo-Pacific reefs maintain higher coral cover and typically recover rapidly after disturbances. This difference in reef resilience is largely due to much higher coral recruitment rates in the Pacific. We hypothesized that the lack of Caribbean coral recruitment might be explained by diminishing quality of settlement cues and/or impaired sensitivity of Caribbean coral larvae to those cues, relative to the Pacific. To evaluate this hypothesis, we assembled a collection of bulk samples of reef encrusting communities, mostly consisting of crustose coralline algae (CCA), from various reefs around the world and tested them as settlement cues for several coral species originating from different ocean provinces. Cue samples were meta-barcoded to evaluate their taxonomic diversity. We observed no systematic differences either in cue potency or in strength of larval responses depending on the ocean province, and no preference of coral larvae towards cues from the same ocean. Instead, we detected significant differences in cue preferences among coral species, even for corals originating from the same reef. We conclude that the region-wide disruption of the settlement process is unlikely to be the major cause of Caribbean reef loss. However, due to their high sensitivity to the effects of climate change, shifts in the composition of CCA-associated communities, combined with pronounced differences in cue preferences among coral species, could substantially influence future coral community structure.


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