Coral reef condition at the Putri Island, Bangka Regency

Putri Island is one of the unique islands which is located in the Bangka Regency. Putri Island has biodiversity ecosystem except for mangrove ecosytems. This study aims to analyze the extent of coral reefs in the shallow waters of Putri Island, and analyze the condition of coral reefs (percentage of cover, life form and coral mortality index). The research was conducted in April – September 2021 at Putri Island with using Line Intercept Transect (LIT) method. The research station divided in to 4 stations where was determined by purposive sampling The results show a map of the distribution of coral reefs in the Putri Island, Bangka Regency. Result show that condition of coral reefs at the research location is a good condition.

Status Terkini Tutupan Terumbu Karang di Perairan Dangkal Pulau Bedil, Desa Labuan Bajo, Kabupaten Sumbawa, NTB

Bedil Island is included in the Keramat, Bedil, and Temudong Small Island Park (TPK), which was approved by the Regent of Sumbawa. Administratively, this island is included in the Labuan Bajo Village area, Sumbawa, NTB. There is the existence of coral reef ecosystems in these waters that form a reef flat and reef slope profile, that stretches to the southwest and northeast. By its designation as a small island park, the coral reefs in Bedil Island are used as an underwater tourism object. This study aims to determine the current condition of coral reef cover in the waters around Bedil Island, especially in the eastern and southern parts of the island. Coral reefs in the north and west area are limited and there is the existence of seagrass beds. The line intercept transect method is carried out by spreading the roll meter as far as 50 meters on the east and south sides of the island with a depth of 2-3 meters. The coral lifeform that is tangent with the roll meter is then recorded and then analyzed for the average percent cover, clustering status, and coral mortality index. Coral reefs in the eastern and southern parts of Bedil Island are classified as very good/excellent because they have a percent cover value above 75%. In addition, the coral mortality index value is also relatively small which indicates that the corals are living well. Clearwater conditions and locations far from human settlements are thought to be factors that support coral survival. However, the presence of dead coral algae and rubble still indicates a threat of damage even though the value is small. Algae life on the surface of dead coral also indicates that the coral has been dead for a long time.

Multi-Variate Analyses of Coral Mortality From the 2014–2015 Stony Coral Tissue Loss Disease Outbreak Off Miami-Dade County, Florida

Environmental compliance monitoring associated with the Port Miami dredging project (2013–2015), designed to assess the impact of project-generated sediments on the local coral community, fortuitously captured a thermal bleaching event and the first reports of an emergent, highly contagious, white-plague-like coral disease outbreak in the fall of 2014. The disease, now termed stony coral tissue loss disease (SCTLD), has decimated reefs throughout Florida and is now spreading across the Caribbean. The high prevalence of disease, the number of affected species, and the high mortality of corals affected suggests SCTLD may be the most lethal coral disease ever recorded. Previous analyses of the dredge monitoring data have reached mixed conclusions about the relative impact of dredging on coral mortality and has often parsed out disease susceptible individuals to isolate the impacts of dredging only. We use multi-variate analyses, including time-based survival analyses, to examine the timing and impacts of dredging, coral bleaching, and disease on local coral mortality. By examining the status of corals monthly from the October 2013 to July 2015 observational period, we found that coral mortality was not significantly affected by a coral’s proximity to the dredge site or sediment burial. Instead, coral mortality was most strongly impacted by disease and the emergence of SCTLD during the monitoring period. During the 2-year monitoring period, 26.3% of the monitored corals died, but the only conditions significantly affected by the dredge were partial burial and partial mortality. The strongest link to mortality was due to disease, which impacted coral species differently depending on their susceptibility to SCTLD. The focus on disturbances associated with dredging created a circumstance where the greater impacts of this emergent disease were downplayed, leading to a false narrative of the resulting mortality on the local coral communities. The results of this study reveal that while local events such as a dredging project do have quantifiable effects and can be harmful to corals, regional and global threats that result in mass coral mortality such as thermal stress and disease represent an existential threat to coral reefs and must be urgently addressed.

Impacts of Stony Coral Tissue Loss Disease (SCTLD) on Coral Community Structure at an Inshore Patch Reef of the Upper Florida Keys Using Photomosaics

Since the appearance of stony coral tissue loss disease (SCTLD) on reefs off Miami in 2014, this unprecedented outbreak has spread across the entirety of Florida’s coral reef tract, as well as to many territories throughout the Caribbean. The endemic zone reached the upper Florida Keys by 2016, resulting in partial or complete mortality of coral colonies across numerous species. Disease was first observed at Cheeca Rocks (Islamorada, Florida) in the beginning of 2018, with reports of coral mortality peaking mid-year. The disease was still present at Cheeca Rocks as of March 2020, however, to a lesser degree compared to the initial outbreak. Annual monitoring efforts have been ongoing at Cheeca Rocks since 2012, including repeated benthic photomosaics of a 330 m2 survey zone, spanning six replicate sites. As such, a repository of coral community composition data exists for before and after the disease outbreak that was analyzed to assess the impacts of SCTLD on reef communities at an upper Florida Keys inshore reef. Cheeca Rocks is hypothesized to be a resilient reef due to its persistent high coral cover despite its inshore location, which subjects corals to fluctuating water quality and marginal environmental conditions. Coral populations here have been shown to recover from bleaching events and heat stress with minimal coral mortality. Though colonies of coral species characterized as highly and moderately susceptible to SCTLD (e.g., Colpophyllia natans, Diploria labyrinthiformis, Pseudodiploria strigosa, Orbicella annularis, and O. faveolata) suffered mortality as a result of the outbreak with an average loss of 16.42% relative cover by species, the overall impacts on coral cover and community structure were relatively low, contributing to a loss of total coral cover of only 1.65%. Comparison of photomosaic data to other studies indicate Cheeca Rocks may not have been affected as severely as other sites on Florida’s coral reef tract, underlying this site’s potential role in coral resilience to stressors including bleaching events, land-based pollution, and disease epizootics.

Fishes of Lakshadweep archipelago: new records, review and a revised checklist

Extensive studies on fish diversity in Lakshadweep waters began with Jones and Kumaran’s in 1964. Reports after these authors were sparse and sporadic until the turn of this century. Although recent reports have increased the tally, targeted studies are lacking, and there is a possibility of listing more species for this region. Studies on the diversity and abundance of fishes are due, given the atoll system undergoing rapid changes: structural decline due to several bleaching related coral mortality events, changes in the seagrass meadows, and the increase in fishing reef-associated species. These circumstances call for a revised checklist of fishes for this region, for the latest dates back to 1991. Thus, we present an inventory of ichthyofauna of Lakshadweep atolls based on published literature and incorporating 15 new species records identified through a rapid survey. The new species records for this region are presented here with the diagnostics of these species. The checklist shows 856 species of 432 genera, 43 orders, and 144 families known from these islands, including 16 freshwater forms. 49.3% of the contribution is from 14 fish families having > 15 species each, while the remainder 131 families contributed 52.5%, which have < 15 species. About 154 species belonging to 12 families are known to contribute to the commercial fisheries of these islands. The new records reported in this work for this region are found in the Maldives, and Sri Lanka proves the zoogeographical affinity of these two regions with the Lakshadweep archipelago.

KONDISI EKOSISTEM TERUMBU KARANG DI PERAIRAN KRUENG RAYA, KABUPATEN ACEH BESAR

This study aims to analyze the condition of the coral reef ecosystem including the substrate, genus composition, and the level of coral mortality in the waters of the Malacca Strait, Masjid Raya District, Aceh Besar District. The research was conducted from October 2016 to October 2019 in the waters of the Malacca Strait, Masjid Raya District, Aceh Besar District. The research site is divided into three stations consisting of Lhok Mee Station, Ahmad Rhang Manyang and Benteng Inong Balee Station. Data were collected using the Point Intercept Transect method. The results showed that the condition of coral reefs at Lhok Mee Station was in the damaged category with coral cover ranging from 6.56% - 13.44%. Ahmad Rhang Manyang Station is included in the moderate to good category with coral cover ranging from 38.75% - 67.19%. Meanwhile, Benteng Inong Balee Station is included in the medium category with coral cover ranging from 45.94% - 56.88%. The monitoring results found that 30 coral genera with the highest composition of the coral genera came from the Porites genus, while other coral genera were unevenly distributed. The value of the mortality index for Lhok Mee Station shows a high increase in mortality of live coral to dead coral. Meanwhile, Ahmad Rhang Manyang and Benteng Inong Balee stations have low coral mortality index values.

Local conditions magnify coral loss after marine heatwaves

Climate change threatens coral reefs by causing heat stress events that lead to widespread coral bleaching and mortality. Given the global nature of these mass coral mortality events, recent studies argue that mitigating climate change is the only path to conserve coral reefs. Using a global analysis of 223 sites, we show that local stressors act synergistically with climate change to kill corals. Local factors such as high abundance of macroalgae or urchins magnified coral loss in the year after bleaching. Notably, the combined effects of increasing heat stress and macroalgae intensified coral loss. Our results offer an optimistic premise that effective local management, alongside global efforts to mitigate climate change, can help coral reefs survive the Anthropocene.

Nitrogen enrichment in macroalgae following mass coral mortality

Scleractinian 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.

Effects of the Stony Coral Tissue Loss Disease Outbreak on Coral Communities and the Benthic Composition of Cozumel Reefs

In the Caribbean, disease outbreaks have emerged as significant drivers of coral mortality. Stony Coral Tissue Loss Disease (SCTLD) is a novel white plague-type disease that was first reported off the Florida coast in 2014. This disease affects &gt;20 coral species and is spreading rapidly throughout the Caribbean. In December 2018, SCTLD reached southwestern (SW) Cozumel, one of the healthiest reef systems in the Caribbean. In this study, we integrate data from multiple survey protocols conducted between July 2018 and April 2020 to track the progression of the outbreak in SW Cozumel and to quantify the impacts of SCTLD on coral communities and the benthic composition of reefs. Given that the SCTLD outbreak coincided with a period of prolonged thermal stress that concluded in widespread coral bleaching in autumn 2019, we also investigated whether this event further exacerbated coral mortality. Our findings show that SCTLD spread throughout SW Cozumel in only 2 months and reached a peak after only 5 months. By the summer of 2019, most of the afflicted corals were already dead. Species of the families Meandrinidae, Faviinae, and Montastraeidae showed 33–95% mortality. The widespread coral die-off caused an overall loss of 46% in coral cover followed by a rapid increase of algae cover across all surveyed reefs that persisted until at least April 2020. In November 2019, more than 15% of surveyed coral colonies were bleached. However, we did not find that bleaching further increased coral mortality at either the colony or the community level, which suggests that the coral communities were able to recover from this event despite still being affected by the disease. In conclusion, SCTLD is radically changing the ecology of coral reefs by decimating the populations of several key reef-builders and reconfiguring the benthic assemblages. The actions needed to restore coral populations have to be accompanied by stringent controls related to the effects of climate change, coastal development, and wastewater treatment to improve coral conditions and ecosystem resilience.