scholarly journals Acoustical Measurement and Biot Model for Coral Reef Detection and Quantification

2016 ◽  
Vol 2016 ◽  
pp. 1-11 ◽  
Author(s):  
Henry M. Manik
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Global Climate ◽  
Acoustic Backscatter ◽  
Biot Theory ◽  
Sound Waves ◽  
Acoustic Backscattering ◽  
Marine Sedimentation ◽  
Acoustic Instruments ◽  
Blast Fishing

Coral reefs are coastal resources and very useful for marine ecosystems. Nowadays, the existence of coral reefs is seriously threatened due to the activities of blast fishing, coral mining, marine sedimentation, pollution, and global climate change. To determine the existence of coral reefs, it is necessary to study them comprehensively. One method to study a coral reef by using a propagation of sound waves is proposed. In this research, the measurement of reflection coefficient, transmission coefficient, acoustic backscattering, hardness, and roughness of coral reefs has been conducted using acoustic instruments and numerical modeling using Biot theory. The results showed that the quantification of the acoustic backscatter can classify the type of coral reef.

scholarly journals An economic analysis of blast fishing on Indonesian coral reefs

1999 ◽  
Vol 26 (2) ◽  
pp. 83-93 ◽  
Author(s):  
C. PET-SOEDE ◽  
H.S.J. CESAR ◽  
J.S. PET
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Large Scale ◽  
Cost Benefit ◽  
High Potential ◽  
Coastal Protection ◽  
Economic Costs ◽  
Vast Number ◽  
Potential Value ◽  
Blast Fishing

Characteristics, impacts and economic costs and benefits of blast fishing have been little investigated and they were therefore studied in Indonesia, at the scale of individual fishing households and of Indonesian society as a whole. Although illegal and highly destructive to coral reefs, blast fishing provides income and fish to a vast number of coastal fishers who claim that they have no alternative to make a living. Crew members in small-, medium- and large-scale blast fishing operations earned net incomes per month of US$55, 146 and 197 respectively. Boat owners in the same types of operations earned US$55, 393 and 1100 respectively. These incomes were comparable to the highest incomes in the conventional coastal fisheries. At the individual household level, the differences between the three types of operations show clear incentives for scale enlargement. The cost-benefit balance at the society level was calculated with an economic model. This analysis showed a net loss after 20 years of blast fishing of US$306 800 per km2 of coral reef where there is a high potential value of tourism and coastal protection, and US$33 900 per km2 of coral reef where there is a low potential value. The main quantifiable costs are through loss of the coastal protection function, foregone benefits of tourism, and foregone benefits of non-destructive fisheries. The economic costs to society are four times higher than the total net private benefits from blast fishing in areas with high potential value of tourism and coastal protection. This analysis of characteristics, impact and economics of blast fishing should help to raise the political will to ban blast fishing from Indonesian waters. Moreover, it allows for an evaluation of possible management solutions, taking into account their costs and the socio-economic framework that caused coastal fishers to start using explosives.

scholarly journals Threat of blast fishing on coral diversity in Peucang Island, Ujung Kulon National Park, Indonesia

Ocean Life ◽  
2017 ◽  
Vol 1 (1) ◽  
pp. 26-31
Author(s):  
RADEN WILLY WIGUNA GUMBIRA ◽  
FITRI RIZKIA ◽  
TRI DEWI KUSUMANINGRUM PRIBADI ◽  
MUHAMMAD SYAEFUL HIDAYAT
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
National Park ◽  
Diversity Indices ◽  
Live Coral ◽  
Coral Coverage ◽  
High Concern ◽  
Coral Reef Ecosystems ◽  
Blast Fishing ◽  
Study Sites

Gumbira RWW, Rizkia F, Pribadi TDK, Hidayat MS. 2017. Threat of blast fishing on coral diversity in Peucang Island National Park, Indonesia. Ocean Life 1: 26-31. As a maritime country with high biodiversity, the health of Indonesian coral reefs is of high concern. Coral reef ecosystems are friable, and mortality occurs relatively quickly after disturbance, not only by nature but also by human activities such as fish bombing. Fish bombing is a big issue that has always threatened coral reefs, including in Peucang Island, part of Ujung Kulon National Park, a place that is protected by law to preserve its natural diversity. A study on coral coverage was conducted to observe the condition of corals and related biota in a coral reef ecosystem. Data was collected using Point Intercept Transect method in 2m and 8m depths. The results showed that coral coverage in 8-meter depth is only 44.02 percent of the live coral in 2-meter depth. The reduction in the value of Diversity Indices, Dominance Indices as well as the Evenness Index in all study sites led to low diversity, with no dominance by a particular species at any of the study sites. The results also showed that corals are well distributed in both depths. Over the past three years, the damage to corals in Peucang Island had generally increased by 0.7 percent due to fish bombing activities.

scholarly journals Missing the Reef for the Corals: Unexpected Trends Between Coral Reef Condition and the Environment at the Ecosystem Scale

2021 ◽  
Vol 8 ◽  
Author(s):  
Eric J. Hochberg ◽  
Michelle M. Gierach
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Coral Cover ◽  
Global Climate ◽  
Meta Analysis ◽  
Current Understanding ◽  
Goods And Services ◽  
Public Data ◽  
The Impact ◽  
Reef Condition

It is incontrovertible that many coral reefs are in various stages of decline and may be unable to withstand the effects of global climate change, jeopardizing vital ecosystem goods and services to hundreds of millions of people around the world. An estimated 50% of the world's corals have already been lost, and those remaining may be lost by 2030 under the “business as usual” CO2 emissions scenario. However, the foundation of these predictions is a surprisingly sparse dataset, wherein ~0.01–0.1% of the world's reef area has been quantitatively surveyed. Further, the available data comprise observations at the 1–10 m scale, which are not evenly spaced across reefs, but often clustered in areas representing focused survey effort. This impedes modeling and predicting the impact of a changing environment at the ecosystem scale. Here we highlight deficiencies in our current understanding of the relationship between coral reefs and their environments. Specifically, we conduct a meta-analysis using estimates of coral cover from a variety of local surveys, quantitatively relating reef condition to a suite of biogeophysical forcing parameters. We find that readily available public data for coral cover exhibit unexpected trends (e.g., a positive correlation between coral cover and multi-year cumulative thermal stress), contrary to prevailing scientific expectations. We illustrate a significant gap in our current understanding, and thereby prediction, of coral reefs at the ecosystem scale that can only be remedied with uniform, high-density data across vast coral reef regions, such as that from remote sensing.

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.

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.

Prominence of environmental and anthropogenic agents on the occurrence of coral reef bleaching syndrome and coral diseases

2024 ◽  
Vol 74 (10) ◽  
pp. 6139-2024
Author(s):  
MICHAŁ SCHULZ ◽  
ALEKSANDRA ŁOŚ ◽  
PATRYCJA SKOWRONEK ◽  
ANETA STRACHECKA
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Oil Spills ◽  
Global Scale ◽  
Ecological Processes ◽  
Coral Diseases ◽  
Rapid Changes ◽  
Anthropogenic Threats ◽  
Negative Factors ◽  
Main Relationship

Coral reefs are the most productive ecosystems on Earth. They ensure the conservation of biodiversity and are a live habitat for 25% of all marine organisms. The main relationship on the coral reef is the symbiosis between corals and algae from the genus Symbiodinium (commonly called zooxanthellae). The authors of this publication have characterized and described the factors limiting the occurrence of coral reefs, including: water temperature, salinity, access to sunlight, contamination, physicochemical and hydromechanical parameters of water. Moreover anthropogenic threats to coral reefs have been specified, including diving tourism, ecological disasters (e.g. oil spills) and the development of marine aquaristics. Rapid changes in the basic living conditions are dangerous for corals and their symbionts and may cause the unsuitability of the new environment resulting in diseases such as coral bleaching. Corals bleaching is a disease associated with the break of the coral and algae relationship which results in a coral reef death on a global scale. Awareness of these negative factors, often related to human activity, may allow us to better understand the ecological processes that are the basis of reef functioning and might enable us to prevent and oppose to the changes and ecological recessions of coral reefs.

scholarly journals Turbid Coral Reefs: Past, Present and Future—A Review

Diversity ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 251
Author(s):  
Adi Zweifler (Zvifler) ◽  
Michael O’Leary ◽  
Kyle Morgan ◽  
Nicola K. Browne
Keyword(s):  
Climate Change ◽  
Coral Reef ◽  
Coral Reefs ◽  
Environmental Change ◽  
Scientific Literature ◽  
Conservation Status ◽  
Climate Change Impacts ◽  
Geographic Range ◽  
Reef Complex ◽  
Sediment Input

Increasing evidence suggests that coral reefs exposed to elevated turbidity may be more resilient to climate change impacts and serve as an important conservation hotspot. However, logistical difficulties in studying turbid environments have led to poor representation of these reef types within the scientific literature, with studies using different methods and definitions to characterize turbid reefs. Here we review the geological origins and growth histories of turbid reefs from the Holocene (past), their current ecological and environmental states (present), and their potential responses and resilience to increasing local and global pressures (future). We classify turbid reefs using new descriptors based on their turbidity regime (persistent, fluctuating, transitional) and sources of sediment input (natural versus anthropogenic). Further, by comparing the composition, function and resilience of two of the most studied turbid reefs, Paluma Shoals Reef Complex, Australia (natural turbidity) and Singapore reefs (anthropogenic turbidity), we found them to be two distinct types of turbid reefs with different conservation status. As the geographic range of turbid reefs is expected to increase due to local and global stressors, improving our understanding of their responses to environmental change will be central to global coral reef conservation efforts.

scholarly journals Stokes drift through corals

2021 ◽  
Author(s):  
Joseph J. Webber ◽  
Herbert E. Huppert
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Porous Layer ◽  
Large Scale ◽  
Fluid Layer ◽  
Ocean Waves ◽  
Stokes Drift ◽  
Inviscid Fluid ◽  
Porous Bed ◽  
Vertical Drift

AbstractMotivated by shallow ocean waves propagating over coral reefs, we investigate the drift velocities due to surface wave motion in an effectively inviscid fluid that overlies a saturated porous bed of finite depth. Previous work in this area either neglects the large-scale flow between layers (Phillips in Flow and reactions in permeable rocks, Cambridge University Press, Cambridge, 1991) or only considers the drift above the porous layer (Monismith in Ann Rev Fluid Mech 39:37–55, 2007). Overcoming these limitations, we propose a model where flow is described by a velocity potential above the porous layer and by Darcy’s law in the porous bed, with derived matching conditions at the interface between the two layers. Both a horizontal and a novel vertical drift effect arise from the damping of the porous bed, which requires the use of a complex wavenumber k. This is in contrast to the purely horizontal second-order drift first derived by Stokes (Trans Camb Philos Soc 8:441–455, 1847) when working with solely a pure fluid layer. Our work provides a physical model for coral reefs in shallow seas, where fluid drift both above and within the reef is vitally important for maintaining a healthy reef ecosystem (Koehl et al. In: Proceedings of the 8th International Coral Reef Symposium, vol 2, pp 1087–1092, 1997; Monismith in Ann Rev Fluid Mech 39:37–55, 2007). We compare our model with field measurements by Koehl and Hadfield (J Mar Syst 49:75–88, 2004) and also explain the vertical drift effects as documented by Koehl et al. (Mar Ecol Prog Ser 335:1–18, 2007), who measured the exchange between a coral reef layer and the (relatively shallow) sea above.

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