scholarly journals ­Inshore, turbid coral reefs from northwest Borneo exhibiting low diversity, but high cover show evidence of resilience to various environmental stressors

2018 ◽  
Author(s):  
Christina Brown ◽  
Nicola Browne ◽  
Jennifer L McIlwain ◽  
Jens Zinke
Keyword(s):  
Coral Reefs ◽  
Coral Cover ◽  
Synergistic Effects ◽  
Coral Disease ◽  
Sediment Accumulation ◽  
Land Development ◽  
Direct Result ◽  
Wet Season ◽  
Mucus Production ◽  
Hard Coral Cover

For reefs in SE Asia the synergistic effects of rapid land-development, insufficient environmental policies and a lack of enforcement has led to poor water quality and compromised coral health from increased sediment and pollution. Those inshore turbid coral reefs, subject to significant sediment inputs, may also inherit some resilience to the effects of thermal stress and coral bleaching. We studied the inshore turbid reefs near Miri, in northwest Borneo, through a comprehensive assessment of coral cover, health and function in addition to quantifying sediment-related parameters. Although Miri Reefs had comparatively low coral species diversity, dominated by massive and encrusting forms of Diploastrea, Porites, Montipora, Favites, Dipsastrea and Pachyseris, they were characterised by a healthy cover ranging from 22-39%. We found a strong inshore to offshore gradient in hard coral cover, diversity and community composition as a direct result of spatial differences in sediment but over scales of <10 km. As well as distance to shore, we included other environmental variables like reef depth and sediment accumulation/size that explained 62.5% of variation in benthic composition among sites. None of the reefs showed evidence of coral disease and relatively low prevalence of compromised health signs including bleaching (6.7%), bioerosion (6.6%), pigmentation (2.2%), scars (1.1%) and mucus production (0.5%). There were, however, seasonal differences in bioerosion rates which increased five-fold after the 2017 wet season. Tagged colonies of Diploastrea and Pachyseries showing partial bleaching in 2016, had fully recovered by 90-100% the following year. Differences in measures of coral function like that of symbiont density and chlorophyll a for Montipora, Pachyseris and Acropora were not detected among sites. This study provides further evidence that turbid coral reefs exposed to seasonally elevated sediment loads can exhibit relatively high coral cover and be resilient to disease and elevated sea surface temperatures.

scholarly journals ­Inshore, turbid coral reefs from northwest Borneo exhibiting low diversity, but high cover show evidence of resilience to various environmental stressors

2018 ◽  
Author(s):  
Christina Brown ◽  
Nicola Browne ◽  
Jennifer L McIlwain ◽  
Jens Zinke
Keyword(s):  
Coral Reefs ◽  
Coral Cover ◽  
Synergistic Effects ◽  
Coral Disease ◽  
Sediment Accumulation ◽  
Land Development ◽  
Direct Result ◽  
Wet Season ◽  
Mucus Production ◽  
Hard Coral Cover

For reefs in SE Asia the synergistic effects of rapid land-development, insufficient environmental policies and a lack of enforcement has led to poor water quality and compromised coral health from increased sediment and pollution. Those inshore turbid coral reefs, subject to significant sediment inputs, may also inherit some resilience to the effects of thermal stress and coral bleaching. We studied the inshore turbid reefs near Miri, in northwest Borneo, through a comprehensive assessment of coral cover, health and function in addition to quantifying sediment-related parameters. Although Miri Reefs had comparatively low coral species diversity, dominated by massive and encrusting forms of Diploastrea, Porites, Montipora, Favites, Dipsastrea and Pachyseris, they were characterised by a healthy cover ranging from 22-39%. We found a strong inshore to offshore gradient in hard coral cover, diversity and community composition as a direct result of spatial differences in sediment but over scales of <10 km. As well as distance to shore, we included other environmental variables like reef depth and sediment accumulation/size that explained 62.5% of variation in benthic composition among sites. None of the reefs showed evidence of coral disease and relatively low prevalence of compromised health signs including bleaching (6.7%), bioerosion (6.6%), pigmentation (2.2%), scars (1.1%) and mucus production (0.5%). There were, however, seasonal differences in bioerosion rates which increased five-fold after the 2017 wet season. Tagged colonies of Diploastrea and Pachyseries showing partial bleaching in 2016, had fully recovered by 90-100% the following year. Differences in measures of coral function like that of symbiont density and chlorophyll a for Montipora, Pachyseris and Acropora were not detected among sites. This study provides further evidence that turbid coral reefs exposed to seasonally elevated sediment loads can exhibit relatively high coral cover and be resilient to disease and elevated sea surface temperatures.

scholarly journals Borneo coral reefs subject to high sediment loads show evidence of resilience to various environmental stressors

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7382 ◽  
Author(s):  
Nicola Browne ◽  
Christina Braoun ◽  
Jennifer McIlwain ◽  
Ramasamy Nagarajan ◽  
Jens Zinke
Keyword(s):  
Coral Reefs ◽  
Coral Cover ◽  
Synergistic Effects ◽  
Coral Disease ◽  
Stable State ◽  
Land Development ◽  
Direct Result ◽  
Wet Season ◽  
Mucus Production ◽  
Sediment Loads

For reefs in South East Asia the synergistic effects of rapid land development, insufficient environmental policies and a lack of enforcement has led to poor water quality and compromised coral health from increased sediment and pollution. Those inshore turbid coral reefs, subject to significant sediment inputs, may also inherit some resilience to the effects of thermal stress and coral bleaching. We studied the inshore turbid reefs near Miri, in northwest Borneo through a comprehensive assessment of coral cover and health in addition to quantifying sediment-related parameters. Although Miri’s Reefs had comparatively low coral species diversity, dominated by massive and encrusting forms of Diploastrea, Porites, Montipora, Favites, Dipsastrea and Pachyseris, they were characterized by a healthy cover ranging from 22 to 39%. We found a strong inshore to offshore gradient in hard coral cover, diversity and community composition as a direct result of spatial differences in sediment at distances <10 km. As well as distance to shore, we included other environmental variables like reef depth and sediment trap accumulation and particle size that explained 62.5% of variation in benthic composition among sites. Miri’s reefs showed little evidence of coral disease and relatively low prevalence of compromised health signs including bleaching (6.7%), bioerosion (6.6%), pigmentation response (2.2%), scars (1.1%) and excessive mucus production (0.5%). Tagged colonies of Diploastrea and Pachyseris suffering partial bleaching in 2016 had fully (90–100%) recovered the following year. There were, however, seasonal differences in bioerosion rates, which increased five-fold after the 2017 wet season. Differences in measures of coral physiology, like that of symbiont density and chlorophyll a for Montipora, Pachyseris and Acropora, were not detected among sites. We conclude that Miri’s reefs may be in a temporally stable state given minimal recently dead coral and a limited decline in coral cover over the last two decades. This study provides further evidence that turbid coral reefs exposed to seasonally elevated sediment loads can exhibit relatively high coral cover and be resilient to disease and elevated sea surface temperatures.

scholarly journals New Scales to Guide the Assessment of Hard Coral Cover and Diversity in the Philippines

2020 ◽  
pp. 121-126
Keyword(s):  
Ecosystem Services ◽  
Coral Reefs ◽  
Coral Cover ◽  
Rapid Identification ◽  
The Philippines ◽  
Hard Coral ◽  
Hard Coral Cover ◽  
Assessment Scales

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.

scholarly journals Detecting sedimentation impacts to coral reefs resulting from dredging the Port of Miami, Florida USA

2016 ◽  
Author(s):  
Margaret W Miller ◽  
Jocelyn Karazsia ◽  
Carolyn E Groves ◽  
Sean Griffin ◽  
Tom Moore ◽  
...  
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Coral Disease ◽  
Sediment Accumulation ◽  
Biological Response ◽  
Time Frame ◽  
Tissue Loss ◽  
Coral Tissue ◽  
Live Coral ◽  
Monitoring Methods

The federal channel at Port of Miami, Florida, USA, was dredged between late 2013 and early 2015, to widen and deepen the channel. While the precise effects of the dredging on surrounding coral reefs are not well quantified, previously published remote sensing analyses, as well as agency and anecdotal reports suggest the most severe and largest area of sedimentation occurred on a coral reef feature referred to as the Inner Reef, particularly in the sector north of the channel. A regional warm-water mass bleaching event followed by a coral disease outbreak during this same time frame confounded the assessment of dredging-related impacts to coral reefs adjacent to the federal channel. In-water field assessments conducted after the completion of dredging and a time series analysis of tagged corals photographed pre-, during, and post-dredging, are used to discern dredging-related sedimentation impacts for the Inner Reef north. Results indicate increased sediment accumulation, severe in certain times and places, and an associated biological response, including significantly greater proportion of live coral tissue loss, occurred within coral reef sites located closer to the channel. Dredging projects near valuable and sensitive habitats subject to local and global stressors require monitoring methods capable of discerning non-dredging related impacts and adaptive management to ensure predicted and unpredicted project-related impacts are quantified. Anticipated increasing frequency and intensity of warming stress also suggests that manageable- but- unavoidable local stressors such as dredging should be partitioned from the warmest times of year.

scholarly journals Ecological Vulnerability of Coral Reef Ecosystem in Wakatobi National Park During Indian Ocean Dipole Event

2020 ◽  
Vol 27 (1) ◽  
pp. 57
Author(s):  
Hawis H. Madduppa ◽  
Alan F. Koropitan ◽  
Ario Damar ◽  
Beginer Subhan ◽  
Muhammad Taufik ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Coral Reefs ◽  
Adaptive Capacity ◽  
Indian Ocean Dipole ◽  
Coral Cover ◽  
Indian Ocean Dipole Event ◽  
Ecological Vulnerability ◽  
Climate Exposure ◽  
Hard Coral Cover ◽  
Site Adaptability

This research examines coral reefs vulnerability which threatening its existences and functions by climate change. The ecological vulnerability in Wakatobi (Wangi-wangi, Kaledupa, Tomia, and Binongko) was assessed during Indian Ocean Dipole (IOD) event in 2016. Climate exposure was determined using sea surface temperature, chlorophyll-a concentration, and wind speed magnitude; sensitivity was determined using coral susceptibility, fish susceptibility, and macroalgae primary productivity rate; then adaptive capacity was developed by hard coral cover, coral size distribution, coral richness, fish biomass, herbivore diversity, and herbivore grazing relative to algal production. The values of Exposure, Sensitivity, and Adaptive capacity in Wakatobi were 0.93±0.02, 0.42±0.18, and 0.44±0.10, respectively. Site specific vulnerability scores ranged from 0.52 to 1.60 (mean 0.92±0.26). Binongko was the least vulnerable than other islands. Tomia was observed as the least adaptive capacity and Wangi-wangi was the most bleaching incidents. These results could help coral reefs monitoring priority during the event and then when the event is gone by focusing on the marked islands and sites. Sites that were observed as more vulnerable is urgently need a management strategy to overcome the vulnerability status in the future, such as increasing site adaptability.

scholarly journals KONDISI TERUMBU KARANG PADA KAWASAN WISATA PANTAI MALALAYANG KOTA MANADO PROVINSI SULAWESI UTARA DENGAN MENGGUNAKAN METODE UNDERWATER PHOTO TRANSECT

2021 ◽  
Vol 9 (1) ◽  
pp. 44
Author(s):  
Devidson Daud ◽  
Joshian N. W. Schaduw ◽  
Chatrien Luzianna Sinjal ◽  
Janny D Kusen ◽  
Erli Y Kaligis ◽  
...  
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Coral Cover ◽  
Computer Software ◽  
Digital Camera ◽  
Hard Coral ◽  
Software Technology ◽  
Technological Developments ◽  
Moderate Condition ◽  
Hard Coral Cover

Coral reefs are coastal ecosystems with the highest level of diversity with around one million species worldwide. Corals are invertebrates belonging to the Phylum Coelenterate (hollow animals) or Cnidaria. The Underwater Photo Transect (UPT) method is a method that utilizes technological developments, both digital camera technology and computer software technology. Capturing data in the field in the form of underwater photos carried out by shooting using a Canon G-16 camera equipped with a waterproof protector (housing). In this study it can be seen that the percentage of hard corals at point 1 is in the medium category, point 2 is in the medium category, and point 3 is in the bad category with the percentage of hard coral cover as follows: point 1 (one) 29.75%, point 2 (two) 31.16%, and point 3 (three) 24.26%, of the three points can represent the overall condition of the coral reefs in Malalayang Beach which is in moderate condition with a percentage of 28.39%.Keywords: Malalayang Beach, Coral Reef, UPT, CPCe

scholarly journals Komposisi Spesies Ikan Karang Di Perairan Desa Bunutan, Kecamatan Abang, Kabupaten Karangasem, Bali

2017 ◽  
Vol 3 (1) ◽  
pp. 91
Author(s):  
I Gusti Ngurah Agung Dhananjaya ◽  
I Gede Hendrawan ◽  
Elok Faiqoh
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Species Composition ◽  
Reef Fish ◽  
Coral Cover ◽  
Good Condition ◽  
Breeding Grounds ◽  
Target Fish ◽  
Marine Site ◽  
Hard Coral Cover

Bunutan village is located in the Abang Subdistrict, Karangasem Regency, Bali. Marines of Bunutan has a coral reef coverage and reef fish under the water. This study aims to determine the species composition of reef fish in marine of Bunutan. The methods used to take reef fish data is Visual Census along 50 meters transect parallel a coastline at a depth of ±5 meters. Result of this study shows thats abudance of reef fish is about 1513 individual from 68 species and 18 family all around transect. The highest abudance derived from Pomacentridae Family with a total 1055 individual from 22 species founded. The composition of species in Bunutan marine site generally in a good condition with high diversity H’ = 3,188418, uniformity is fairly stable with value E = 0,753032 and with the value of dominance C = 0,069245 or nothing of coral reef fish which dominate each other. In terms of role fish in the sea, reef fish in Bunutan marine site have major fish about 92%, target fish 2% and indicator fish 6%. When relating to the condition of coral reefs in the marines of Bunutan, hard coral cover percentage is on 48.5% to 54.5% thats indicates the condition of coral reefs on moderate to good condition. The condition of coral reefs is utilized by reef fish as a place of refuge, feeding or breeding grounds, causing the species composition of reef fish in the marine of Bunutan on relatively good.

scholarly journals Spatial variation in the benthic community composition of coral reefs in the Wakatobi Marine National Park, Indonesia: updated baselines and limited benthic community shifts

2019 ◽  
Vol 100 (1) ◽  
pp. 37-44
Author(s):  
Joseph Marlow ◽  
Abdul Haris ◽  
Jamal Jompa ◽  
Shinta Werorilangi ◽  
Tracey Bates ◽  
...  
Keyword(s):  
Coral Reefs ◽  
Spatial Variation ◽  
Benthic Community ◽  
Coral Cover ◽  
Spatial Scales ◽  
Benthic Communities ◽  
Spatial And Temporal Scales ◽  
The World ◽  
Study Sites ◽  
Hard Coral Cover

AbstractCoral reefs have experienced extensive degradation across the world over the last 50 years as a result of a variety of stressors operating at a range of spatial and temporal scales. In order to assess whether declines are continuing, or if reefs are recovering, detailed baseline information is required from across wide spatial scales. Unfortunately, for some regions this information is not readily available, making future reef trajectories difficult to determine. Here we characterized the current benthic community state for coral reefs in the Wakatobi region of Indonesia, one of the most biodiverse marine regions in the world. We surveyed 10 reef sites (5, 10 and 15 m depth) to explore spatial variation in coral reef benthic communities and provide a detailed baseline. Previous data (2002–2011) were available for coral, sponges, algae and soft coral at six of our study sites. Using this information, we determined if any changes had occurred in dominance of these benthic groups. We found that benthic assemblage composition differed significantly over relatively small spatial scales (2–10 km) and hard coral cover was highly variable, ranging from 7–48% (average 19.5% ± 1.5 SE). While coral cover appears to have declined at all sites where data were available since 2002, we found little evidence for widespread increases in other benthic groups or regime shifts. Our study provides a comprehensive baseline dataset for the region that can be used in the future to determine rates of change in benthic communities.

scholarly journals The change of coral cover in Ujong Pancu waters, Peukan Bada Sub-District, Aceh Besar

2021 ◽  
Vol 869 (1) ◽  
pp. 012051
Author(s):  
M Ulfah ◽  
M Muliari ◽  
F Azzahara ◽  
N M Razi ◽  
M R Fazillah ◽  
...  
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Coral Cover ◽  
Hard Coral ◽  
Ecological Functions ◽  
Coral Genus ◽  
The Earth ◽  
Coral Reef Ecosystems ◽  
Hard Coral Cover

Abstract Coral reef ecosystems are one of the most productive ecosystems on the earth, with large ecological functions. The disruption of coral reef ecosystems has a significant impact on the surrounding biota. This study aims to determine the condition of coral reefs for the last three years in Ujong Pancu waters, Peukan Bada sub-district, Aceh Besar district. This study uses data in 2017, 2018, and 2019 with three observation locations: Lhok Keeutapang, Lhok Mata Ie, and Tuan Island. The method used is Point Intercept Transect (PIT) with a transect length of 20 m with four repetitions. The results showed that the percentage of hard coral cover in the Ujong Pancu waters decreased from the good category (50.31%) in 2017 to moderate (47.81%) in 2019. The percentage with the highest coral cover was at the Lhok Keutapang location at 72, 81% in 2018, while the lowest coral cover at the Tuan Island location was 15.94% in 2017. The composition of the coral genus found also decreased from 12 coral genera (2017) to 9 coral genera (2019).

scholarly journals NON-RANDOM TIMING OF ECOLOGICAL SHIFTS ON CARIBBEAN CORAL REEFS SUGGESTS REGIONAL CAUSES OF CHANGE

2019 ◽  
Author(s):  
William F. Precht ◽  
Richard B. Aronson ◽  
Toby A. Gardner ◽  
Jennifer A. Gill ◽  
Julie P. Hawkins ◽  
...  
Keyword(s):  
Coral Reef ◽  
Coral Reefs ◽  
Nutrient Loading ◽  
Coral Cover ◽  
Coral Disease ◽  
Regional Scale ◽  
Negative Relationship ◽  
Grazing Pressure ◽  
Coral Mortality ◽  
Macroalgal Cover

AbstractCaribbean reefs have experienced unprecedented changes in the past four decades. Of great concern is the perceived widespread shift from coral to macroalgal dominance and the question of whether it represents a new, stable equilibrium for coral-reef communities. The primary causes of the shift -- grazing pressure (top-down), nutrient loading (bottom-up) or direct coral mortality (side-in) -- still remain somewhat controversial in the coral reef literature. We have attempted to tease out the relative importance of each of these causes. Four insights emerge from our analysis of an early regional dataset of information on the benthic composition of Caribbean reefs spanning the years 1977–2001. First, although three-quarters of reef sites have experienced coral declines concomitant with macroalgal increases, fewer than 10% of the more than 200 sites studied were dominated by macroalgae in 2001, by even the most conservative definition of dominance. Using relative dominance as the threshold, a total of 49 coral-to-macroalgae shifts were detected. This total represents ∼35% of all sites that were dominated by coral at the start of their monitoring periods. Four shifts (8.2%) occurred because of coral loss with no change in macroalgal cover, 15 (30.6%) occurred because of macroalgal gain without coral loss, and 30 (61.2%) occurred owing to concomitant coral decline and macroalgal increase. Second, the timing of shifts at the regional scale is most consistent with the side-in model of reef degradation, which invokes coral mortality as a precursor to macroalgal takeover, because more shifts occurred after regional coral-mortality events than expected by chance. Third, instantaneous observations taken at the start and end of the time-series for individual sites showed these reefs existed along a continuum of coral and macroalgal cover. The continuous, broadly negative relationship between coral and macroalgal cover suggests that in some cases coral-to-macroalgae phase shifts may be reversed by removing sources of perturbation or restoring critical components such as the herbivorous sea urchin Diadema antillarum to the system. The five instances in which macroalgal dominance was reversed corroborate the conclusion that macroalgal dominance is not a stable, alternative community state as has been commonly assumed. Fourth, the fact that the loss in regional coral cover and concomitant changes to the benthic community are related to punctuated, discrete events with known causes (i.e. coral disease and bleaching), lends credence to the hypothesis that coral reefs of the Caribbean have been under assault from climate-change-related maladies since the 1970s.

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