scholarly journals Spatial distribution of epibenthic molluscs on a sandstone reef in the Northeast of Brazil

2012 ◽  
Vol 72 (2) ◽  
pp. 287-298 ◽  
Author(s):  
AS. Martinez ◽  
LF. Mendes ◽  
TS. Leite

The present study investigated the distribution and abundance of epibenthic molluscs and their feeding habits associated to substrate features (coverage and rugosity) in a sandstone reef system in the Northeast of Brazil. Rugosity, low coral cover and high coverage of zoanthids and fleshy alga were the variables that influenced a low richness and high abundance of a few molluscan species in the reef habitat. The most abundant species were generalist carnivores, probably associated to a lesser offer and variability of resources in this type of reef system, when compared to the coral reefs. The results found in this study could reflect a normal characteristic of the molluscan community distribution in sandstone reefs, with low coral cover, or could indicate a degradation state of this habitat if it is compared to coral reefs, once that the significantly high coverage of fleshy alga has been recognized as a negative indicator of reef ecosystems health.

2013 ◽  
Vol 5 ◽  
pp. 69 ◽  
Author(s):  
Susana Perera Valderrama ◽  
Pedro M. Alcolado ◽  
Hansel Caballero Aragón ◽  
Elena De la Guardia Llansó ◽  
Dorka Cobián Rojas

En el 2007 se evaluó el estado de salud de los arrecifes coralinos del Parque Nacional Guanahacabibes, Cuba, sobre la base de la condición de las comunidades de corales. Se analizaron indicadores de condición de los corales escleractinios (diámetro máximo, riqueza de especies, enfermedades y mortalidad) a distintas profundidades, en 13 estaciones con diferentes niveles de exposición a los principales fenómenos océano-atmosféricos generadores de oleaje en el área (vientos nortes, sures y alisios). Se identificaron 42 especies de corales pétreos. Las más abundantes fueron: Siderastrea siderea, Montastraea faveolata, Agaricia agaricites y Porites astreoides. El promedio de cobertura de coral vivo varió entre 4.8% y 31.2%, con un promedio general de 17%. El análisis integrado de todos los indicadores de condición de las comunidades de corales sugirió la existencia de dos áreas diferenciadas según la exposición a los vientos y el consecuente efecto del oleaje y los sedimentos. La primera área abarcó el este de la Bahía de Corrientes (entre Uvero Quemado y Cuevas de Pedro), la más resguardada, y donde los indicadores biológicos sugieren un ambiente más favorable. La segunda comprendió la parte occidental más expuesta (entre Veral y Faro Roncali), que presentó la mayor cobertura relativa del conjunto de especies resistentes a la sedimentación, especialmente en 10 y 15 m de profundidad. Estos resultados indican que los arrecifes del Parque Nacional Guanahacabibes no escapan del proceso de degradación que afrontan la mayoría de los arrecifes de la región del Caribe.AbstractIn 2007, a health assessment of coral reefs in the Guanahacabibes National Park, Cuba, was conducted based onthe condition of coral communities. Coral condition indicators (maximum diameter, species richness, diseases andmortality) were evaluated, at different depths in 13 sites with varying exposure levels to the main ocean-atmosphericphenomena that generate waves in the area (north, south and trade winds). Forty two species of stony corals wereidentified. The most abundant species were Siderastrea siderea, Montastraea faveolata, Agaricia agaricites and Porites astreoides. The average coral cover varied between 4.8% and 31.2%, with a general average of 17%. Theintegrated analysis of all condition indicators of coral communities suggested the existence of two distinctive areasaccording to wind exposure and the consequent effect of both waves and sediments. The first area, covering east ofBahía de Corrientes (between Uvero Quemado and Cuevas de Pedro), was more protected and had a more favorableenvironment, as suggested by the biological indicators. The second area was comprised of the western part,was more exposed (between Veral and Faro Roncali), and showed the highest relative cover of species resistant tosedimentation, especially at 10 and 15 m deep. These results indicate that coral reefs at the Guanahacabibes NationalPark do not escape from the degradation process faced by most coral reefs in the Caribbean region.


2013 ◽  
Vol 5 ◽  
pp. 69 ◽  
Author(s):  
Susana Perera Valderrama ◽  
Pedro M. Alcolado ◽  
Hansel Caballero Aragón ◽  
Elena De la Guardia Llansó ◽  
Dorka Cobián Rojas

En el 2007 se evaluó el estado de salud de los arrecifes coralinos del Parque Nacional Guanahacabibes, Cuba, sobre la base de la condición de las comunidades de corales. Se analizaron indicadores de condición de los corales escleractinios (diámetro máximo, riqueza de especies, enfermedades y mortalidad) a distintas profundidades, en 13 estaciones con diferentes niveles de exposición a los principales fenómenos océano-atmosféricos generadores de oleaje en el área (vientos nortes, sures y alisios). Se identificaron 42 especies de corales pétreos. Las más abundantes fueron: Siderastrea siderea, Montastraea faveolata, Agaricia agaricites y Porites astreoides. El promedio de cobertura de coral vivo varió entre 4.8% y 31.2%, con un promedio general de 17%. El análisis integrado de todos los indicadores de condición de las comunidades de corales sugirió la existencia de dos áreas diferenciadas según la exposición a los vientos y el consecuente efecto del oleaje y los sedimentos. La primera área abarcó el este de la Bahía de Corrientes (entre Uvero Quemado y Cuevas de Pedro), la más resguardada, y donde los indicadores biológicos sugieren un ambiente más favorable. La segunda comprendió la parte occidental más expuesta (entre Veral y Faro Roncali), que presentó la mayor cobertura relativa del conjunto de especies resistentes a la sedimentación, especialmente en 10 y 15 m de profundidad. Estos resultados indican que los arrecifes del Parque Nacional Guanahacabibes no escapan del proceso de degradación que afrontan la mayoría de los arrecifes de la región del Caribe.AbstractIn 2007, a health assessment of coral reefs in the Guanahacabibes National Park, Cuba, was conducted based onthe condition of coral communities. Coral condition indicators (maximum diameter, species richness, diseases andmortality) were evaluated, at different depths in 13 sites with varying exposure levels to the main ocean-atmosphericphenomena that generate waves in the area (north, south and trade winds). Forty two species of stony corals wereidentified. The most abundant species were Siderastrea siderea, Montastraea faveolata, Agaricia agaricites and Porites astreoides. The average coral cover varied between 4.8% and 31.2%, with a general average of 17%. Theintegrated analysis of all condition indicators of coral communities suggested the existence of two distinctive areasaccording to wind exposure and the consequent effect of both waves and sediments. The first area, covering east ofBahía de Corrientes (between Uvero Quemado and Cuevas de Pedro), was more protected and had a more favorableenvironment, as suggested by the biological indicators. The second area was comprised of the western part,was more exposed (between Veral and Faro Roncali), and showed the highest relative cover of species resistant tosedimentation, especially at 10 and 15 m deep. These results indicate that coral reefs at the Guanahacabibes NationalPark do not escape from the degradation process faced by most coral reefs in the Caribbean region.


Coral Reefs ◽  
2021 ◽  
Author(s):  
Eleanor J. Vaughan ◽  
Shaun K. Wilson ◽  
Samantha J. Howlett ◽  
Valeriano Parravicini ◽  
Gareth J. Williams ◽  
...  

AbstractScleractinian corals are engineers on coral reefs that provide both structural complexity as habitat and sustenance for other reef-associated organisms via the release of organic and inorganic matter. However, coral reefs are facing multiple pressures from climate change and other stressors, which can result in mass coral bleaching and mortality events. Mass mortality of corals results in enhanced release of organic matter, which can cause significant alterations to reef biochemical and recycling processes. There is little known about how long these nutrients are retained within the system, for instance, within the tissues of other benthic organisms. We investigated changes in nitrogen isotopic signatures (δ15N) of macroalgal tissues (a) ~ 1 year after a bleaching event in the Seychelles and (b) ~ 3 months after the peak of a bleaching event in Mo’orea, French Polynesia. In the Seychelles, there was a strong association between absolute loss in both total coral cover and branching coral cover and absolute increase in macroalgal δ15N between 2014 and 2017 (adjusted r2 = 0.79, p = 0.004 and adjusted r2 = 0.86, p = 0.002, respectively). In Mo’orea, a short-term transplant experiment found a significant increase in δ15N in Sargassum mangarevense after specimens were deployed on a reef with high coral mortality for ~ 3 weeks (p < 0.05). We suggest that coral-derived nutrients can be retained within reef nutrient cycles, and that this can affect other reef-associated organisms over both short- and long-term periods, especially opportunistic species such as macroalgae. These species could therefore proliferate on reefs that have experienced mass mortality events, because they have been provided with both space and nutrient subsidies by the death and decay of corals.


2021 ◽  
Vol 14 (9) ◽  
pp. 1-7
Author(s):  
N.D. Hung ◽  
L.T.H. Thuy ◽  
T.V. Hang ◽  
T.N. Luan

The coral reef ecosystem in Cu Lao Cham, Vietnam is part of the central zone of the Cu Lao Cham -Hoi An, a biosphere reserve and it is strictly protected. However, the impacts of natural disasters - tropical cyclones (TCs) go beyond human protection. The characteristic feature of TCs is strong winds and the consequences of strong winds are high waves. High waves caused by strong TCs (i.e. level 13 or more) cause decline in coral cover in the seas around Cu Lao Cham. Based on the relationship between sea surface temperature (SST) and the maximum potential intensity (MPI) of TCs, this research determines the number of strong TCs in Cu Lao Cham in the future. Using results from a regional climate change model, the risk is that the number of strong TCs in the period 2021-2060 under the RCP4.5 scenario, will be 3.7 times greater than in the period 1980-2019 and under the RCP 8.5 scenario it will be 5.2 times greater than in the period 1980-2019. We conclude that increases in SST in the context of climate change risks will increase the number and intensity of TCs and so the risk of their mechanical impact on coral reefs will be higher leading to degradation of this internationally important site.


Author(s):  
Jenny E House ◽  
Luc M Bidaut ◽  
Alec P Christie ◽  
Oscar Pizarro ◽  
Maria Dornelas

Coral reefs are a valuable and vulnerable marine ecosystem. The structure of coral reefs influences their health and ability to fulfill ecosystem functions and services. However, monitoring reef corals largely relies on 1D or 2D estimates of coral cover and abundance that overlook change in ecologically significant aspects of the reefs because they do not incorporate vertical or volumetric information. This study explores the relationship between 2D and 3D metrics of coral size. We show that surface area and volume scale consistently with planar area, albeit with morphotype specific conversion parameters. We use a photogrammetric approach using open-source software to estimate the ability of photogrammetry to provide measurement estimates of corals in 3D. Technological developments have made photogrammetry a valid and practical technique for studying coral reefs. We anticipate that these techniques for moving coral research from 2D into 3D will facilitate answering ecological questions by incorporating the 3rd dimension into monitoring.


2021 ◽  
Vol 324 ◽  
pp. 03007
Author(s):  
Ni Wayan Purnama Sari ◽  
Rikoh Manogar Siringoringo ◽  
Muhammad Abrar ◽  
Risandi Dwirama Putra ◽  
Raden Sutiadi ◽  
...  

Observations of the condition of coral reefs have been carried out in Spermonde waters from 2015 to 2018. The method used in this observation uses Underwater Photo Transect (UPT), and the data obtained is analyzed using CPCe (Coral Point Count with Excel Extensions) software. The results show that the percentage of coral cover has increased from year to year. The percentage of live coral cover in 2015 was 19.64%, 23.60 in 2016, 23.72% in 2017, and 27.83% in 2018. The increase in live coral cover from year to year is thought to occur due to the availability of nutrients. or increasing public awareness, considering this location is one of the most famous tourist attractions in Makassar. Coral reef health index values can be used to classify coral reef health. Through the analysis of the coral reef health index, an index value of 4 was obtained, which means that the condition of the coral reefs is in the “moderate” category.


Coral reefs supply vital ecosystem services to the Philippines. Safeguarding these services requires the rapid identification of reefs that provide most services, and identification is best made by measuring hard coral cover and diversity and using updated and locally relevant assessment scales on these measurements. The use of these assessment scales has advantages and is recommended to update and improve Philippine laws.


2021 ◽  
Vol 8 ◽  
Author(s):  
Juan L. Torres-Pérez ◽  
Carlos E. Ramos-Scharrón ◽  
William J. Hernández ◽  
Roy A. Armstrong ◽  
Maritza Barreto-Orta ◽  
...  

Land-based sediment stress represents a threat to many coral reefs in Puerto Rico primarily as a result of unrestricted land cover/land use changes and poor best management practices. The effects of such stresses have been documented along most coasts around the island. However, little attention has been paid to reefs located on the north coast, and very little is known about their composition and current state. Here, we present a study characterizing riverine inputs, water quality conditions, and benthic composition of two previously undescribed coral reefs (Tómbolo and Machuca reefs) located just eastward of the Río Grande de Manatí outlet in north-central Puerto Rico. This study utilizes a time series of remotely sensed ocean color products [diffuse vertical attenuation coefficient at 490 nm (Kd490) and chlorophyll-a concentration (Chl-a) estimated with data from the Visible Infrared Imaging Radiometer Suite (VIIRS)] to characterize water quality in this coastal region. In general, the months with relatively high mean daily river streamflow also coincide with months having the highest proportion of eastward wave direction, which can promote the eastward influence of river waters toward the two coral reefs sites. Kd490 and Chl-a showed a higher riverine influence closer to the watershed outlet. Kd490 and Chl-a monthly peaks also coincide with river streamflow highs, particularly at those pixels closer to shore. Tómbolo Reef, located farther eastward of the river outlet, shows a well-developed primary reef framework mainly composed of threatened reef-building species (Acropora palmata, Pseudodiploria) and high coral cover (19–51%). The benthos of Machuca Reef, located closer to the river outlet, is dominated by macroalgae with a significantly lower coral cover (0.2–2.7%) mainly composed of “weedy” coral species (Porites astreoides and Siderastrea radians). Cover of major benthic components correlates with distance from the river outlet, and with gradients in Kd490 and Chl-a, with higher coral cover and lower macroalgal cover farther from the river outlet. Coral cover at Tómbolo Reef is higher than what has been reported for similar sites around Puerto Rico and other Caribbean islands showing its ecological importance, and as up until now, an unrecognized potential refuge of reef-building threatened coral species.


2020 ◽  
Vol 2 (2) ◽  
pp. 77
Author(s):  
Rega Permana ◽  
Nora Akbarsyah ◽  
Pringgo KDNY Putra ◽  
Aulia Andhikawati

The coral reef ecosystem is one of the typical tropical ecosystems with high biodiversity which has an important role both biologically, ecologically, physically as well as socially and economically. Several coral reef areas in Indonesia were reported to have suffered damage, not only due to climate change which has an impact on rising sea surface temperatures and ocean acidification but also due to anthropogenic factors and irresponsible management of marine tourism. This study aimed to analyze the condition of coral reefs based on covering in Pramuka Island, which is one of the famous tourist destinations in the Seribu Islands. The study was conducted using Line Intercept Transect (LIT) method at predetermined coordinate points. The results showed that the dominant coral reef life form was Acropora Submassive (ACS), namely 18.9%, and Acropora Branching (ACB) as much as 12.48%. Besides, the types of life forms found were coral foliase (9.42%), Miliepora Coral (9.2%), Coral Massive (4.8%), Acropora Encrustring (4.24%), and so on. Based on the results of this study, it can be concluded that the condition of coral reefs in Pramuka Island is still relatively good with a total coral cover percentage of 72.38%. Efforts to protect the coral reef ecosystem in this area need to be considered so that its condition can be maintained. 


Sign in / Sign up

Export Citation Format

Share Document