scholarly journals In situ effects of simulated overfishing and eutrophication on settlement of benthic coral reef invertebrates in the Central Red Sea

Author(s):  
Christian Jessen ◽  
Christian R. Voolstra ◽  
Christian Wild

In the Central Red Sea, relatively pristine coral reefs meet intense coastal development, but data on the effects of related stressors for reef functioning are lacking. This in situ study therefore investigated the independent and combined effects of simulated overfishing and eutrophication on settlement of reef associated invertebrates on light-exposed and -shaded tiles over 4 months. Findings revealed that at the end of the study period invertebrates had almost exclusively colonized shaded tiles, indicating that algae were superior settling competitors on light-exposed tiles. On the shaded tiles, simulated overfishing prevented settlement of hard corals, but significantly increased settlement of polychaetes, while simulated eutrophication only significantly decreased hard coral settlement relative to controls. The combined treatment significantly increased settlement of bryozoans and bivalves compared to controls and individual manipulations, but significantly decreased polychaetes compared to simulated overfishing. These results suggest settlement of polychaetes and hard corals as potential bioindicators for overfishing and eutrophication, respectively, and settlement of bivalves and bryozoans for a combination of both. Therefore, if investigated stressors are not controlled, phase shifts from dominance by hard corals to that by other invertebrates may occur at shaded reef locations in the Central Red Sea.

Author(s):  
Christian Jessen ◽  
Christian R. Voolstra ◽  
Christian Wild

In the Central Red Sea, relatively pristine coral reefs meet intense coastal development, but data on the effects of related stressors for reef functioning are lacking. This in situ study therefore investigated the independent and combined effects of simulated overfishing and eutrophication on settlement of reef associated invertebrates on light-exposed and -shaded tiles over 4 months. Findings revealed that at the end of the study period invertebrates had almost exclusively colonized shaded tiles, indicating that algae were superior settling competitors on light-exposed tiles. On the shaded tiles, simulated overfishing prevented settlement of hard corals, but significantly increased settlement of polychaetes, while simulated eutrophication only significantly decreased hard coral settlement relative to controls. The combined treatment significantly increased settlement of bryozoans and bivalves compared to controls and individual manipulations, but significantly decreased polychaetes compared to simulated overfishing. These results suggest settlement of polychaetes and hard corals as potential bioindicators for overfishing and eutrophication, respectively, and settlement of bivalves and bryozoans for a combination of both. Therefore, if investigated stressors are not controlled, phase shifts from dominance by hard corals to that by other invertebrates may occur at shaded reef locations in the Central Red Sea.


2021 ◽  
Vol 22 (11) ◽  
Author(s):  
Anggita Kartikasari ◽  
TODHI PRISTIANTO ◽  
RIZKI HANINTYO ◽  
EGHBERT ELVAN AMPOU ◽  
TEJA ARIEF WIBAWA ◽  
...  

Abstract. Kartikasari A, Pristianto T, Hanintyo R, Ampou EE, Wibawa TA, Borneo BB. 2021. Representative benthic habitat mapping on Lovina coral reefs in Northern Bali, Indonesia. Biodiversitas 22: 4766-4774. Satellite optical imagery datasets integrated with in situ measurements are widely used to derive the spatial distribution of various benthic habitats in coral reef ecosystems. In this study, an approach to estimate spatial coverage of those habitats based on observation derived from Sentinel-2 optical imagery and a field survey, is presented. This study focused on the Lovina coral reef ecosystem of Northern Bali, Indonesia to support deployment of artificial reefs within the Indonesian Coral Reef Garden (ICRG) programme. Three specific locations were explored: Temukus, Tukad Mungga, and Baktiseraga waters. Spatial benthic habitat coverages of these three waters was estimated based on supervised classification techniques using 10m bands of Sentinel-2 imagery and the medium scale approach (MSA) transect method of in situ measurement.The study indicates that total coverage of benthic habitat is 61.34 ha, 25.17 ha, and 27.88 ha for Temukus, Tukad Mungga, and Baktiseraga waters, respectively. The dominant benthic habitat of those three waters consists of sand, seagrass, coral, rubble, reef slope and intertidal zone. The coral reef coverage is 29.48 ha (48%) for Temukus covered by genus Acropora, Isopora, Porites, Montipora, Pocillopora. The coverage for Tukad Mungga is 8.69 ha (35%) covered by genus Acropora, Montipora, Favia, Psammocora, Porites, and the coverage for Baktiseraga is 11.37 ha (41%) covered by genus Montipora sp, Goniastrea, Pavona, Platygyra, Pocillopora, Porites, Acropora, Leptoseris, Acropora, Pocillopora, Fungia. The results are expected to be suitable as supporting data in restoring coral reef ecosystems in the northern part of Bali, especially in Buleleng District.


2020 ◽  
Vol 12 (2) ◽  
pp. 263
Author(s):  
Idris Idris ◽  
Neviaty P. Zamani ◽  
Suharsono Suharsono ◽  
Fakhrurrozi Fakhrurrozi

HighlightDamage to coral reefs by ship aground is twice the area of a football fieldFound four zones of damage including runoff, dune, blow and dispersalMortality of live coral and other benthic biota ranges from 75-100% in the affected locationThe form of damaged live coral growth is predominantly slow growing.Eight hard coral species were found on the IUCN-Redlist list with a vulnerable status.AbstractShip grounding on coral reefs often results in physical and biological damage, including dislodging and removal of corals from reefs, destruction of coral skeletons, erosion and removal of sediment deposits, and loss of three-dimensional complexity. Indonesia, as an archipelagic country, is very vulnerable to various pressures; for example, the case of ship grounding is a great concern of scientists, managers, divers, and sailors themselves. Most of the damage is very severe. The purpose of the research conducted is to identify the condition of the live coral cover, mapping the type and extent of coral reef damage, affected coral species, their conservation status, and to quantify the extent of the area of coral reef damage. Measuring the extent of damage to coral reef ecosystems using the fishbone method, while the level of damage and its impact was measured using the Underwater Photo Transect (UPT) and belt transect method. The event of the grounding of the MV Lyric Poet on the Bangka Waters, Bangka-Belitung Province, has caused damage to the coral reef ecosystem. There are four damage zones identified, i.e., trajectory, mound, propeller, and dispersion zone. Corals are damaged with a total area of 13.540m2; equivalent to twice that of an international football field. Diversity of hard coral found as many as 49 species included in the CITES-Appendix II. A total of eight protected species are included in the IUCN Red List with extinction-prone status.


Coral Reefs ◽  
2020 ◽  
Vol 39 (6) ◽  
pp. 1605-1618
Author(s):  
Miriam Reverter ◽  
Matthew Jackson ◽  
Nauras Daraghmeh ◽  
Christian von Mach ◽  
Nina Milton

AbstractCorals from the Gulf of Aqaba (northern Red Sea) are resilient to high temperatures and therefore this region is regarded as globally important for reef conservation. However, long-term dynamics of coral reef assemblages from the Gulf of Aqaba remain largely understudied. In this study, we analysed the change in benthic, fish and invertebrate assemblages of reefs around Dahab (South Sinai, Egypt) between 2009 and 2019. We also studied the individual trajectories of coral reef benthic categories, key invertebrate and fish species and their relationship. As site emerged as the main factor explaining the variability in coral reef communities, we identified three clusters of sites with similar assemblages. Both benthic, fish and invertebrate assemblages changed considerably at the three site clusters between 2009 and 2019. We found significant increases in fleshy macroalgae (~ 6 to 15%) and cyanobacterial mats (~ 6 to 12%) in all site clusters. Although not observing a significant reduction of hard coral cover, both macroalgae mat cover and cyanobacterial mat cover were significantly negatively related to hard coral cover and hard coral disease. Soft coral cover (mainly corals from the Xeniidae family) decreased significantly in two of the site clusters, their cover being negatively related to macroalgal and cyanobacterial cover. Significant declines in grazer urchins were observed at all site clusters, and a strong negative relationship was found with macroalgae and cyanobacterial mats cover, suggesting urchin decline as one of the main drivers behind algal increases. Different site clusters had different fish trajectories (butterflyfish, parrotfish, surgeonfish and predators), with only damselfish densities significantly decreasing at all sites. A significant decrease in damselfish densities was related to increases in cyanobacterial mats. These findings suggest that if macroalgae and cyanobacteria continue to increase, Dahab coral reefs could undergo degradation, and therefore, more studies are needed to elucidate the drivers behind these algal increases.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Netanel Kramer ◽  
Gal Eyal ◽  
Raz Tamir ◽  
Yossi Loya
Keyword(s):  
Red Sea ◽  

2020 ◽  
Author(s):  
Aishah Norashikin Abdul A’ziz ◽  
Fatin Izzati Minhat ◽  
Pan Hui-Juan ◽  
Hasrizal Shaari ◽  
Wan Nurzalia Wan Saelan ◽  
...  

Abstract Pulau Tioman is one of the famous tourism islands in Peninsular Malaysia due to the beautiful terrestrial and coral reefs ecosystem. This study aims to assess and monitor the health of coral reef sites surrounding Pulau Tioman based on the application of Foraminifera in Reef Assessment and Monitoring (FORAM) Index. A total of ten selected sampling sites from west and east side of Pulau Tioman were setup in front of the major beach areas around Pulau Tioman. At each site, 100 m transect was laid out from shore towards the reef slope and surface sediment samples were collected at 50 m intervals. Eight orders, 41 families, 80 genera and 161 species of benthic foraminifera were identified around Pulau Tioman. Amphistegina lessonii found to be the most dominant species and the least dominant species (< 4%) are Bolivina vadescens, Elphidium neosimplex, Heterolepa dutemplei, Heterolepa subhaidingerii, Mikrobelodontos bradyi, Milliolinella suborbicularis, Operculina discoidalis, Parahourinoides fragillissimus, Quinqueloculina incisa, Quinqueloculina sulcate, Triloculinella bertheliniana and Triloculinella parisa. The highest and lowest numbers of species was recorded at station J3 and station F3. The agglutinated type of foraminifera contributed between 2–8% of the total assemblages. Meanwhile, calcareous hyaline and porcelaneous group represent 79% and 19% of total assemblages respectively. Based on the functional groups, symbiont-bearing taxa were the most common foraminiferal found in most of the stations. The present study indicates that majority of sampling sites around Pulau Tioman are conducive for coral reef growth and could recover from any future bleaching events or temporary damage in the ecosystem. However, several areas with higher coastal development and tourism activities has reduced water quality (FI < 4) and chances of better reef recovery. Thus, the number of visitors and tourists should be revised in order to produce a better condition for coral reefs to grow. This assumption is based on the established results of the FORAM index. Thus, we suppose that FORAM index could be used together with coral reef health index in other reef ecosystems around Malaysia to determine the condition and status of coral reef area.


PLoS ONE ◽  
2013 ◽  
Vol 8 (6) ◽  
pp. e66992 ◽  
Author(s):  
Christian Jessen ◽  
Cornelia Roder ◽  
Javier Felipe Villa Lizcano ◽  
Christian R. Voolstra ◽  
Christian Wild

2015 ◽  
Vol 2 (1) ◽  
pp. 507
Author(s):  
Miftahul Huda ◽  
Suwarno Hadisusanto ◽  
Encus Widyatmoko

<p>Coral reef ecosystem has diverse shape and stunning beauty. It has high value on both ecological and economical aspect it has productivity greater than other marine life. Local Marine Conservation Area, Bengkayang, West Kalimantan (Lemukutan island, Penata Besar island, Penata Kecil island, Seluas island, Rahdayan island) has a high potential on coastal and marine natural resources especially coral reefs ecosystem. The study was purposed to determine the condition coral reef ecosystem and the diversity of hard corals (Scleractinia). Samples have been taking from 5-7 meters depth in every point using Line Intercept Transect method (LIT). The observation result from the coral reef in Local Marine Conservation Area showed as the followings varies from bad to good (13.82 – 69.00%), but biotic components were found in each area that consist of sediment with percentage of 4.32-37.68% and the rock of 2.57- 38.22%. Hard coral community consists of 35 species including seven families. Genus Acropora as hard coral species is dominating the five islands. The damage of coral reefs that occurs in most of the study area is due to increased suspended material (sediments). </p><p><strong>Keywords</strong>: Coral reefs, Scleractinia, Acropora, LIT, Local Marine Conservation Area, Bengkayang, West Kalimantan.</p>


2021 ◽  
Vol 9 (1) ◽  
pp. 44
Author(s):  
Devidson Daud ◽  
Joshian N. W. Schaduw ◽  
Chatrien Luzianna Sinjal ◽  
Janny D Kusen ◽  
Erli Y Kaligis ◽  
...  

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


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