Coral recovery at Aldabra Atoll, Seychelles: five years after the 1998 bleaching event

2005 ◽  
Vol 363 (1826) ◽  
pp. 251-255 ◽  
Author(s):  
Ben Stobart ◽  
Kristian Teleki ◽  
Raymond Buckley ◽  
Nigel Downing ◽  
Martin Callow
Keyword(s):  
Large Scale ◽  
Considerable Increase ◽  
Coral Cover ◽  
Method Comparison ◽  
Research Programme ◽  
Coralline Algae ◽  
Maximum Diameter ◽  
Bleaching Event ◽  
Hard Coral ◽  
Coral Recovery

Changes in reef benthos were assessed at Aldabra Atoll following the mass coral bleaching event of 1998. Video transects were used to survey the benthos and analysed using the Australian Institute of Marine Science five–dot method. Comparison of coral cover data collected by the Cambridge Southern Seychelles Atoll Research Programme with data collected during this study revealed that mortality of coral at Aldabra following the bleaching event was approximately 66% at 10 m depth and 38% at 20 m depth. Five years on, there are signs of hard coral recovery at some locations, but in spite of several years of high coral recruitment (7–9 recruits per m 2 at 10 m depth, 4–6 recruits per m 2 at 20 m depth, where recruits are defined as any colony under 5 cm maximum diameter), recovery of hard coral has not occurred at a significant level. There has been a considerable increase in soft coral cover at some locations, which was dominated by the genus Rhytisma . Macro algal cover did not increase following the bleaching event, although, as would be expected, dead corals have been colonized by coralline algae. There have been no further events leading to large–scale coral mortality at Aldabra since 1998.

scholarly journals Assessing population collapse of Drupella spp. (Mollusca: Gastropoda) 2 years after a coral bleaching event in the Republic of Maldives

Hydrobiologia ◽  
2021 ◽  
Author(s):  
L. Saponari ◽  
I. Dehnert ◽  
P. Galli ◽  
S. Montano
Keyword(s):  
Coral Bleaching ◽  
Prey Availability ◽  
Coral Cover ◽  
Environmental Data ◽  
High Plasticity ◽  
Bleaching Event ◽  
Coral Recovery ◽  
The Republic ◽  
The Impact ◽  
Line Intercept

AbstractCorallivory causes considerable damage to coral reefs and can exacerbate other disturbances. Among coral predators, Drupella spp. are considered as delayer of coral recovery in the Republic of Maldives, although little information is available on their ecology. Thus, we aimed to assess their population structure, feeding behaviour and spatial distribution around 2 years after a coral bleaching event in 2016. Biological and environmental data were collected using belt and line intercept transects in six shallow reefs in Maldives. The snails occurred in aggregations with a maximum of 62 individuals and exhibited a preference for branching corals. Yet, the gastropods showed a high plasticity in adapting feeding preferences to prey availability. Drupella spp. were homogenously distributed in the study area with an average of 9.04 ± 19.72 ind/200 m2. However, their occurrence was significantly different at the reef scale with the highest densities found in locations with higher coral cover. The impact of Drupella spp. appeared to be minimal with the population suffering from the loss of coral cover. We suggest that monitoring programs collect temporal- and spatial-scale data on non-outbreaking populations or non-aggregating populations to understand the dynamics of predation related to the co-occurrence of anthropogenic and natural impacts.

scholarly journals Coral Reef Recovery in the Mexican Caribbean after 2005 Mass Coral Mortality—Potential Drivers

Diversity ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 338
Author(s):  
Xochitl E. Elías Ilosvay ◽  
Ameris I. Contreras-Silva ◽  
Lorenzo Alvarez-Filip ◽  
Christian Wild
Keyword(s):  
Coral Cover ◽  
Geographical Location ◽  
Relative Effect ◽  
Significant Loss ◽  
Coral Mortality ◽  
Hard Coral ◽  
Mexican Caribbean ◽  
Algae Growth ◽  
Reef Recovery ◽  
Coral Recovery

In 2005, an extreme heatwave hit the Wider Caribbean, followed by 13 hurricanes (including hurricanes Emily and Wilma) that caused significant loss in hard coral cover. However, the drivers of the potential recovery are yet to be fully understood. Based on recent findings in the literature of coral cover recovery in the Mexican Caribbean after the mass bleaching event and associated hurricanes in 2005, this study analyzed, through random-effects meta-analysis, the hard coral and macroalgae benthic development and potential drivers of change between 2005 and 2016 in the Mexican Caribbean. Therefore, we tested the relative effect of sea surface temperature (SST), chlorophyll-a water concentration, coastal human population development, reef distance to shore, and geographical location on both hard coral and macroalgae cover over time. Findings revealed increases of both hard coral (by 6%) and algae cover (by ca. 14%, i.e., almost three times the increase of corals) over 12 years. Although our findings confirm the partial coral recovery after the 2005 Caribbean mass coral mortality event, they also indicate rapid colonization of algae across the region. Surprisingly, only SST correlated negatively with changes in coral cover. Contrary to expectations, there was a significantly greater algae cover increase in the Central section of the Mexican Caribbean, which is characterized by a low population density. However, a constant discharge of nutrient-rich freshwater may have facilitated algae growth there. This study reports partial regional reef recovery, but it also indicates that local factors, particularly eutrophication, facilitate algae growth at a speed that is much faster than coral recovery.

scholarly journals Early trajectories of benthic coral reef communities following the 2015/16 coral bleaching event at remote Aldabra Atoll, Seychelles

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Anna Koester ◽  
Valentina Migani ◽  
Nancy Bunbury ◽  
Amanda Ford ◽  
Cheryl Sanchez ◽  
...  
Keyword(s):  
Coral Reef ◽  
Water Temperature ◽  
Coral Bleaching ◽  
Coral Cover ◽  
Bleaching Event ◽  
Hard Coral ◽  
Reef Communities ◽  
Remote Sites ◽  
Hard Coral Cover ◽  
Coral Reef Communities

Abstract Documenting post-bleaching trajectories of coral reef communities is crucial to understand their resilience to climate change. We investigated reef community changes following the 2015/16 bleaching event at Aldabra Atoll, where direct human impact is minimal. We combined benthic data collected pre- (2014) and post-bleaching (2016–2019) at 12 sites across three locations (lagoon, 2 m depth; seaward west and east, 5 and 15 m depth) with water temperature measurements. While seaward reefs experienced relative hard coral reductions of 51–62%, lagoonal coral loss was lower (− 34%), probably due to three-fold higher daily water temperature variability there. Between 2016 and 2019, hard coral cover did not change on deep reefs which remained dominated by turf algae and Halimeda, but absolute cover on shallow reefs increased annually by 1.3% (east), 2.3% (west) and 3.0% (lagoon), reaching, respectively, 54%, 68% and 93% of the pre-bleaching cover in 2019. Full recovery at the shallow seaward locations may take at least five more years, but remains uncertain for the deeper reefs. The expected increase in frequency and severity of coral bleaching events is likely to make even rapid recovery as observed in Aldabra’s lagoon too slow to prevent long-term reef degradation, even at remote sites.

scholarly journals The mortality, recovery, and community shifts of scleractinian corals in Puerto Rico one decade after the 2005 regional bleaching event

2017 ◽  
Author(s):  
Jorge R García-Sais ◽  
Stacey M Williams ◽  
Ali Amirrezvani
Keyword(s):  
Puerto Rico ◽  
Coral Cover ◽  
Light Attenuation ◽  
Coral Community ◽  
Scleractinian Corals ◽  
Partial Recovery ◽  
Bleaching Event ◽  
Before And After ◽  
Coral Recovery ◽  
And Shifts

This work analyzes the mortality, recovery, and shifts in the composition of scleractinian corals in Puerto Rico one decade after the 2005 regional coral bleaching event. Temporal and spatial patterns of coral community structure were examined using a stratified, non-random sampling approach based on five permanent transects per reef at 16 reef stations. A negative correlation between percent coral cover loss and light attenuation coefficient (Kd490) was observed, suggesting that water turbidity played a major role in coral protection during the bleaching event (“sunblock effect”). Loss of coral cover after the bleaching event was lower at nearshore reefs, and with increasing depth at oceanic and shelf-edge reefs. By 2015, coral recovery was observed at all reefs surveyed, but coastal reefs exhibited a higher rate of recovery. The responses of coral assemblages varied after the bleaching event, including shifts in cover from massive corals (Orbicella spp.) to turf algae and/or by opportunistic (Porites astreoides) and branching corals (Madracis auretenra, P. porites); partial recovery by O. annularis complex; and no measurable change in coral assemblages before and after the event.

scholarly journals The mortality, recovery, and community shifts of scleractinian corals in Puerto Rico one decade after the 2005 regional bleaching event

2017 ◽  
Author(s):  
Jorge R García-Sais ◽  
Stacey M Williams ◽  
Ali Amirrezvani
Keyword(s):  
Puerto Rico ◽  
Coral Cover ◽  
Light Attenuation ◽  
Coral Community ◽  
Scleractinian Corals ◽  
Partial Recovery ◽  
Bleaching Event ◽  
Before And After ◽  
Coral Recovery ◽  
And Shifts

This work analyzes the mortality, recovery, and shifts in the composition of scleractinian corals in Puerto Rico one decade after the 2005 regional coral bleaching event. Temporal and spatial patterns of coral community structure were examined using a stratified, non-random sampling approach based on five permanent transects per reef at 16 reef stations. A negative correlation between percent coral cover loss and light attenuation coefficient (Kd490) was observed, suggesting that water turbidity played a major role in coral protection during the bleaching event (“sunblock effect”). Loss of coral cover after the bleaching event was lower at nearshore reefs, and with increasing depth at oceanic and shelf-edge reefs. By 2015, coral recovery was observed at all reefs surveyed, but coastal reefs exhibited a higher rate of recovery. The responses of coral assemblages varied after the bleaching event, including shifts in cover from massive corals (Orbicella spp.) to turf algae and/or by opportunistic (Porites astreoides) and branching corals (Madracis auretenra, P. porites); partial recovery by O. annularis complex; and no measurable change in coral assemblages before and after the event.

MONITORING CORAL RECOVERY AT NEARSHORE CORAL REEFS IN PHANGNGA PROVINCE, THE ANDAMAN SEA FOLLOWING THE 2010 CORAL BLEACHING EVENT

2017 ◽  
Author(s):  
Makamas Sutthacheep ◽  
Makamas Sutthacheep ◽  
Thamasak Yeemin ◽  
Thamasak Yeemin ◽  
Sittiporn Pengsakun ◽  
...  
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Coral Bleaching ◽  
Coral Cover ◽  
Global Climate ◽  
Andaman Sea ◽  
Live Coral ◽  
Bleaching Event ◽  
Sea Star ◽  
Coral Recovery

Mass bleaching and subsequent mortality of scleractinian corals in response to elevated seawater temperatures has been considered as one of the most impacts of global climate change. Three extensive coral bleaching events in the Andaman Sea were reported, in the years 1991, 1995 and 2010. Studies on survival of coral colonies, coral recruitment and community structure of coral reef associated macrofauna would predict the trends for coral recovery from the impacts of coral bleaching events. The present study aimed to examine the status of coral communities, density of coral recruits and coral reef associated macrofauna at nearshore coral reefs in Phangnga Province, the Andaman Sea following the 2010 coral bleaching event. The dead coral cover was high (>50%) while the live coral cover was in the range of 13-21%. There was high diversity of coral recruits on natural substrates. The average densities of macrobenthic fauna varied from 1.9 to 2.6 individuals.m-2, with significant differences among study sites. The dominant macrobenthic species were a soft coral (Lobophytum sp.), a sea star (Linckia laevigata) and a sea urchin (Echinostrephus molaris). Coral recovery at these coral reefs would be possible but local anthropogenic stressors must be overwhelmingly reduced in order to enhance coral reef resilience. The long-term monitoring programs in the Andaman Sea are required for decision makers to support their adaptive management approaches.

Coral bleaching in turbid waters of north-western Australia

2017 ◽  
Vol 68 (1) ◽  
pp. 65 ◽  
Author(s):  
A. Lafratta ◽  
J. Fromont ◽  
P. Speare ◽  
C. H. L. Schönberg
Keyword(s):  
Thermal Stress ◽  
Western Australia ◽  
Large Scale ◽  
Coral Cover ◽  
Coral Community ◽  
Soft Corals ◽  
Hard Coral ◽  
Turbid Waters ◽  
Benthic Survey ◽  
North Western

We report severe bleaching in a turbid water coral community in north-western Australia. Towed still imagery was used for a benthic survey near Onslow in March 2013 to assess thermal stress in hard and soft corals, finding 51–68% of all corals fully bleached in 10–15-m water depth. Tabulate or foliaceous Turbinaria was the locally most abundant hard coral (46%), followed by massives such as faviids and poritids (25%) and encrusting coral (12%), thus over 80% of the local corals could be considered to be bleaching resistant. All coral groups were bleached in similar proportions (massive hard corals 51%<soft corals 60%<encrusting hard corals 62%<Turbinaria 62%<‘others’ 68%). NOAA data and environmental assessments suggest previous recurrent thermal stress throughout the last 10 years in the study area. On the basis of these records this stress apparently changed the community structure from bleaching vulnerable species such as Acropora, leaving more tolerant species, and reduced coral cover. We could see no evidence for adaptation or acclimation of corals in this area. Towed still imagery was found to be a suitable means for rapid and large-scale bleaching studies in shallow, turbid areas where diving can be difficult or impossible.

MONITORING CORAL RECOVERY AT NEARSHORE CORAL REEFS IN PHANGNGA PROVINCE, THE ANDAMAN SEA FOLLOWING THE 2010 CORAL BLEACHING EVENT

2017 ◽  
Author(s):  
Makamas Sutthacheep ◽  
Makamas Sutthacheep ◽  
Thamasak Yeemin ◽  
Thamasak Yeemin ◽  
Sittiporn Pengsakun ◽  
...  
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Coral Bleaching ◽  
Coral Cover ◽  
Global Climate ◽  
Andaman Sea ◽  
Live Coral ◽  
Bleaching Event ◽  
Sea Star ◽  
Coral Recovery

Mass bleaching and subsequent mortality of scleractinian corals in response to elevated seawater temperatures has been considered as one of the most impacts of global climate change. Three extensive coral bleaching events in the Andaman Sea were reported, in the years 1991, 1995 and 2010. Studies on survival of coral colonies, coral recruitment and community structure of coral reef associated macrofauna would predict the trends for coral recovery from the impacts of coral bleaching events. The present study aimed to examine the status of coral communities, density of coral recruits and coral reef associated macrofauna at nearshore coral reefs in Phangnga Province, the Andaman Sea following the 2010 coral bleaching event. The dead coral cover was high (>50%) while the live coral cover was in the range of 13-21%. There was high diversity of coral recruits on natural substrates. The average densities of macrobenthic fauna varied from 1.9 to 2.6 individuals.m-2, with significant differences among study sites. The dominant macrobenthic species were a soft coral (Lobophytum sp.), a sea star (Linckia laevigata) and a sea urchin (Echinostrephus molaris). Coral recovery at these coral reefs would be possible but local anthropogenic stressors must be overwhelmingly reduced in order to enhance coral reef resilience. The long-term monitoring programs in the Andaman Sea are required for decision makers to support their adaptive management approaches.

Bottlenecks in the Implementation of On-Site Wastewater Treatment Plants on a Large Scale in The Netherlands

1990 ◽  
Vol 22 (3-4) ◽  
pp. 291-298
Author(s):  
Frits A. Fastenau ◽  
Jaap H. J. M. van der Graaf ◽  
Gerard Martijnse
Keyword(s):  
Wastewater Treatment ◽  
The Netherlands ◽  
Large Scale ◽  
Wastewater Treatment Plants ◽  
Housing Stock ◽  
Research Work ◽  
Field Research ◽  
Domestic Wastewater ◽  
Research Programme ◽  
Definition Of

More than 95 % of the total housing stock in the Netherlands is connected to central sewerage systems and in most cases the wastewater is treated biologically. As connection to central sewerage systems has reached its economic limits, interest in on-site treatment of the domestic wastewater of the remaining premises is increasing. A large scale research programme into on-site wastewater treatment up to population equivalents of 200 persons has therefore been initiated by the Dutch Ministry of Housing, Physical Planning and Environment. Intensive field-research work did establish that the technological features of most on-site biological treatment systems were satisfactory. A large scale implementation of these systems is however obstructed in different extents by problems of an organisational, financial and/or juridical nature and management difficulties. At present research is carried out to identify these bottlenecks and to analyse possible solutions. Some preliminary results are given which involve the following ‘bottlenecks':-legislation: absence of co-ordination and absence of a definition of ‘surface water';-absence of subsidies;-ownership: divisions in task-setting of Municipalities and Waterboards; divisions involved with cost-sharing;-inspection; operational control and maintenance; organisation of management;-discharge permits;-pollution levy;-sludge disposal. Final decisions and practical elaboration of policies towards on-site treatment will have to be formulated in a broad discussion with all the authorities and interest groups involved.

scholarly journals Nitrogen enrichment in macroalgae following mass coral mortality

Coral Reefs ◽  
2021 ◽  
Author(s):  
Eleanor J. Vaughan ◽  
Shaun K. Wilson ◽  
Samantha J. Howlett ◽  
Valeriano Parravicini ◽  
Gareth J. Williams ◽  
...  
Keyword(s):  
Coral Reefs ◽  
Coral Cover ◽  
Strong Association ◽  
French Polynesia ◽  
Mass Mortality ◽  
Transplant Experiment ◽  
Bleaching Event ◽  
Coral Mortality ◽  
Absolute Increase ◽  
Inorganic Matter

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.

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