Coral Reef Areas Research Articles

Benthic foraminifera as bioindicators for assessing reef condition in Kāne‘ohe Bay, O‘ahu, Hawai‘i

Context Tropical coral reef environments provide a wide variety of goods and ecosystem services but are experiencing growing pressure from coastal development and tourism. Assessing the status of reef communities along gradients of human pressure is therefore necessary to predict recovery and resilience capacity of reefs.Aims First, to determine the overall water quality in Kāne‘ohe Bay, O’ahu, Hawai‘i, by employing a low-cost monitoring approach for anthropogenic stress on coral reef areas. Second, to assess the suitability of the monitoring approach to complement existing monitoring programmes.Methods Sediment samples containing benthic foraminifera were used to determine water quality and stressor sources in Kāne‘ohe Bay, O’ahu, Hawai‘i, by applying the Foram Index (FI) and Bayesian regression analysis. The FI is based on relative abundance of functional groups of larger benthic foraminifera.Key results Overall water quality in Kāne‘ohe Bay may support active growth and recovery of coral reefs in the northern sector but deteriorates around Kāne‘ohe City.Conclusions Benthic foraminifera can be used as bio-indicators in Hawaiian reefs, providing an easy and fast-to-apply method for assessing short-term changes in water quality and stress sources. Implementing benthic foraminifera studies within existing long-term monitoring programs of Hawaiian reefs can be beneficial for conservation efforts.Implications Within a historic context, our findings illustrate the modest recovery of an ecosystem following pollution control measures but highlight the need of conservation efforts for reef environments adjacent to major human settlements.

Socio-Spatial Approach to Cultivation of Lobster in the Ekas Bay Area, Lombok, West Nusa Tenggara

Indonesia is one of the countries that has the largest marine wealth in the world with an area of 6.32 million waters with an accumulated coastline of 81,000 km and has a very large coral reef area as one of habitats for lobster. Lobsters live at a depth of 100-200 meters below sea level with a temperature of 20-30°C, with the distribution of lobsters in almost all Indonesian waters. One area of Indonesia’s center for lobster cultivation is West Nusa Tenggara (NTB). The Directorate of Marine Spatial Planning designed a program scheme that was prepared to follow up on Lombok's lobster cultivation center, the lobster estate program or known as lobster cultivation village with blue economy principles. The core of sustainability which in development considering resources in the marine space characteristics that are vulnerable to environmental changes and open access - utilization that is open to the public and everyone can access it freely. Answering how conflicts of interest fight over marine space, it is necessary to pay attention to the relationship between space and the humans involved. This analysis is explained by using Levebvre's Socio-Spatial approach where space neutral and passive geometry. Space represents the site of struggle. In particular, the purpose paper is to add another point of view that already exists in reporting the detailed plan for marine aquaculture utilization zones. This article descriptive qualitative method. Results obtained preparation detailed spatial planning, consider the existence of conflict of interest contestations between stakeholders and accommodate conflicts of interest that may occur.

Application of a SWAT Model for Supporting a Ridge-to-Reef Framework in the Pago Watershed in Guam

This study implemented experimental and numerical approaches for supporting the Pago Bay ridge-to-reef management program. Water quality tests for turbidity and inorganic dissolved nitrogen (IDN) were performed using water samples collected from four sites within the Pago Watershed. After conducting a one-way ANOVA test, the result shows significant differences in group means in turbidity levels (F value = 20.4 and p-value 3.29 × 10−7). Application of Tukey’s HSD test identifies one of the sites, the Pago River section, yields more sediment and IDN to the river system and Pago coral reef area. Observation of heavy rainfall, which causes much of the erosion and sediment transport, over the area should be taken into account in order to create best management practices. In addition, this study proposes a SWAT model for the watershed to identify locations of concern. The SWAT model was calibrated using historical streamflow data for the period of 2012–2018 and validated with data for the period of 2019–2020. The NSE and R2 values for the calibration are 0.864 and 0.938, respectively. For the validation period, the NSE value is 0.857, and the value of R2 is 0.937. In terms of sediments and nutrients, sub-basins connected to Pago River comprise the major source areas. Estimation of more sediment loads during the wet-monsoon season implies that heavy rainfall induces more erosion over the region.

Coral reef monitoring in Panjang Island, Central Bangka

Bangka Island is the largest tin producer in Indonesia and since the granting of tin mining freedom in 2000, unconventional tin mining (TI) is increasingly prevalent. The existence of mining activities will directly or indirectly damage the environment both on land and at sea. Especially the high biodiversity of coral reef ecosystem. The purpose of this research was to analyze a map of the distribution of coral reef based on Sentinel 2A satellite imagery data. Analyze the extent of the coral reefs in shallow waters of Putri Island, and analyze of the condition coral reefs (percentage cover, mortality index and genus diversity) with using collaboration betwen the coral diving data and remote sensing data. Studies of changes in coral reef ecosystems have been ongoing since several decades ago. The combination of satellite imagery and aerial photographs is capable of making long-term and continuous observations on mapping and change detection. Remote sensing technology has several advantages overconventional sampling to monitor a large area in time almost simultaneously and continuously including the difficult to explore areas. This research was conducted with visual interpretation by using standard true color composite band (483) and false color composite band (843) of Sentinel 2A and also using lyzenga transformation. Estimation of coral reefs area based on result is 475,96 ha (2016) and decreased to 475 ha (2021). The condition of coral reefs at the research location is a good condition.

Historical Maps provide insight into a century and a half of habitat change in Fijian coasts.

Meaningful conservation goals require setting baselines derived from long‐term ecological records and information that is rare in many regions of the world. Historical data allow us to shift baselines back in time in order to strengthen conservation outcomes in the future.To explore how different histories of land use and development influenced coastal ecosystems in two Fijian cities (Suva and Savusavu), we compared a series of historical navigational charts. These charts recorded change in coral reef area and coastal mangrove forests, as well as expansions of hardened shorelines. We used geographic information systems (GIS) to georeference and make quantitative comparisons starting in 1,840 in Suva and 1876 in Savusavu.Our findings show that, despite increasing urbanization in the capital Suva, available coral reef habitat has not significantly changed in over 150 years, but development has hastened a nearly 50% loss of mangroves. Meanwhile, in the smaller city of Savusavu, coral habitats suffered significant loss in area and an increase in patchiness. As in Suva, shoreline hardening increased in Savusavu, but this change was not accompanied by a loss of mangroves.Nautical charts provided hitherto unavailable information on the long‐term loss and alteration of coastal habitats in Fiji. Historical ecology allows scientists to combat shifting baseline syndrome and set measured standards for conservation objectives.

Long-Term Changes in the Land–Ocean Ecological Environment in Small Island Countries in the South Pacific: A Fiji Vision

Small island countries in the South Pacific are ecologically fragile areas, vulnerable to climate change, and the long-term ecological changes in the sea and land have an important impact on their sustainable development. This study takes Fiji, a typical small island country in the South Pacific, as an example, to analyze the change and connection of marine and terrestrial ecosystem environments based on 30 years of multi-source, satellite, remote-sensing data. From 1991 to 2019, according to the change in forest area in Fiji, three stages were delineated: first was a period of stability, then a decrease, and then a recovery in recent years. From 1991 to 2002, Fiji’s vegetation accounted for 73% of the total area; sea environment surrounding the islands, such as sea level height and sea surface temperature, were relatively low, with high water transparency. From 2002 to 2014, with the development of forestry and tourism, vegetation decreased by 6.89% and bare land increased, which changes the runoff erosion in the drainage basin; correspondingly, the chlorophyll a concentration in three major estuaries was found to be slightly increased with low water transparency. Meanwhile, coupled with the rising sea temperature, the area of Fiji’s coral reefs shrank significantly, with 51.13% of the total loss of coral reefs occurring in the Vanua Levu, where bare land and runoff were more distributed in its drainage basin. From 2014 to 2019, Fiji’s vegetation and coral reef areas recovered from the former stage; affected by short-term climate oscillations such as El Niño-Southern Oscillation (ENSO), the sea surface temperature showed a significant abnormal drop and the water transparency decreased. In the past 30 years (1993–2018), the sea level rise rate around Fiji reached 4 mm/year, and the temperature increased by 0.3 °C, which threatens the coastal ecosystem environment, including coral reefs and mangrove; inappropriate land-use change would worsen the situation in these ecologically fragile areas.

Global decline in capacity of coral reefs to provide ecosystem services

Global decline in capacity of coral reefs to provide ecosystem services

Short-term sediment plume event in the coral reef area of a small island captured by the Planet Dove satellite constellation

ABSTRACT Sediment discharge from tropical and subtropical islands significantly influence the habitat and survival of the surrounding corals. However, severe observational difficulties have hitherto prevented all the efforts to capture these events and estimate their corresponding effects. Herein, we first report the details about a short but significant sediment plume event in coral reef areas of Kumejima Island, a small island near Okinawa, Japan, based on remote sensing data of high spatio-temporal resolution obtained by the Planet Dove satellite constellation. We developed a model for estimating the concentration of suspended solids (SS) based on laboratory spectral measurements and applied it to the red band of optical satellite data to quantify and map SS concentrations of the plume event. During this event, the level of SS concentrations near the coast were high that can cause acute negative impacts on corals. Our study emphasizes the importance of capturing such short-term events and providing essential information as reference basis for formulating countermeasures to control soil discharges and propose spatial strategies on land aimed at the conservation of coral reef ecosystems.

Spatial Distribution of CO2, CH4, and N2O in the Great Barrier Reef Revealed Through High Resolution Sampling and Isotopic Analysis

AbstractMethane (CH4) and nitrous oxide (N2O) dynamics in coastal coral reef areas are poorly understood. We measured dissolved carbon dioxide (CO2) and CH4 (with δ13C‐CO2 and δ13C‐CH4 isotope fractions) and N2O in the Great Barrier Reef (GBR) to determine spatial distributions and emissions. CO2 (379–589 μatm) was oversaturated due to calcification and riverine sources, as indicated by depleted δ13C‐CO2 values. CH4 (1.5–13.5 nM) was also oversaturated from nearshore biogenic sources indicated by depleted δ13C‐CH4 and probable offshore aerobic production. N2O (5.5–6.6 nM) was generally undersaturated, with uptake highest near the coast. Daily CO2 emissions were 5826 ± 1191 tonnes, with CO2 equivalent (eq) N2O uptake (191 ± 44 tonnes) offsetting 3.3% of CO2 or 89% of CH4eq (214 ± 45 tonnes) emissions based on 20‐year global warming potentials. The GBR was a slight CO2 and CH4 source and N2O sink during our study. However, further work is required to constrain diurnal, seasonal, and spatial dynamics.

First record of the Triplefin fish, Helcogramma ellioti (Herre, 1944), from the Gulf of Oman, Iran (Blennioidei: Tripterygiidae: Tripterygiinae)

First record of the Triplefin fish (Blenniiformes: Tripterygiidae), Helcogramma ellioti , is reported here based on six specimens collected from Chabahar, northern Gulf of Oman in February 2019. Identification was confirmed based on a series of morphological characters including, a minute supraorbital tentacle, 3-5 symphyseal mandibular pores, a numerous number of scales in lateral line (36-37) and a low number of total lateral scale rows (38-39). Specimens were found in coral reef areas at depths of 1-15m of the Gulf of Oman in the Indo-Pacific region. Compared to the other members of Helcogramma , H. ellioti is regarded as a medium to large body size species (25.0-57.0mm SL). Although several species of triplefin fishes have been reported from the Persian Gulf, but, it is the first record from Tripterygiidae for the Iranian waters of the Gulf of Oman.

Seasonal and spatial variation of protist communities from reef water and open ocean water in patchy coral reef areas of a semi-enclosed bay

Protists are an important component of the marine ecosystem and play an essential role in material cycle and energy flow, but the distribution of protists in coral reefs have not been fully studied. In this study, high-throughput amplicon sequencing technology was used to study the biodiversity and community structure of protists from coral reefs and open sea areas, with the typical semi-enclosed bay Daya Bay as the research field. There were significant seasonal differences in the dominant phyla of protists, biodiversity index values and βeta diversity (P < 0.05) but no significant differences in the different sampling areas (P > 0.05). The topological parameters of the co-occurrence network showed the protist co-occurrence network in the open sea had more complex interactions and stronger stability than in the coral reef areas because of the hydrodynamics, waves, and relatively poor nutrients. Redundancy analysis and the Mantel test showed that the structure of the protist community was affected by seawater temperature, pH, salinity, and dissolved oxygen. This study analysed the temporal and spatial differences in protists in the coral reef and open sea areas of Daya Bay to provide important information for the study of protist biodiversity and community structure in semi-enclosed bays.

KAJIAN PENGELOLAAN PESISIR DAN LAUT DENGAN SISTEM ZONASI DI KAWASAN KONSERVASI PERAIRAN DAERAH KECAMATAN LIUKANG TUPPABIRING

Liukang Tuppabiring is a waters with marine biodiversity potential large enough to be developed and managed sustainably. Utilization around the coral reefs in the waters of the Liukang Tuppabiring sub-district currently tends to lead to destructive use, so it is necessary to take damage prevention measures immediately. The results showed the condition of coral cover in the medium and damaged, while at stations 1,2,3,4,6 (25,47-41.07%), while conditions were good at station 5 (56.20%). The number of individual reef fish is 290 individuals from 46 species of 22 genera 11 families. At the research location also identified one type of protected biota namely Hawksbill (Eretmochelys imbricata). Coral damage that occurred at 6 observation stations was more caused by the practice of using destructive and environmentally unfriendly fishing equipment such as bombs, trawls, and the use of poisons. The priority strategies undertaken in the management of coral reefs at the study site are 1) Management of environmentally friendly coral reefs where the community as a manager with strong support from the Government; 2) Making clear rules related to utilization in coral reef areas and establishing a POSMAKWAS institution to avoid more severe coral damage; 3) Improve supervision and law enforcement must be firm in relation to the use of fishing gear that can damage coral reef ecosystems.

Seasonal fluctuations in symbiotic bacteria and their role in environmental adaptation of the scleractinian coral Acropora pruinosa in high-latitude coral reef area of the South China Sea

Coral-associated bacterial communities are paramount for coral ecosystems and holobiont health. However, the role of symbiotic bacteria in the adaptation of high-latitude corals to seasonal fluctuations remains underexplored. Therefore, we used 16S rRNA-based high-throughput sequencing to analyze the symbiotic bacterial diversity, composition, and core bacterial community in high-latitude coral and explored the seasonal fluctuation characteristics of symbiotic bacterial communities. We found that bacterial richness and α-diversity changed significantly across different seasons. Additionally, the community structure recombined seasonally, with different dominant bacterial phyla and genera in different seasons. However, the symbiotic bacterial community structures of Acropora pruinosa in winter and spring were similar. Proteobacteria were the dominant bacteria in spring, autumn, and winter. In summer, the dominant bacterial taxa were Bacteroidota and Proteobacteria. Ralstonia was the dominant bacterial genus in spring and winter, whereas in autumn, BD1-7_clade was dominant. Linear discriminant analysis effect size identified 20 abundant genera between the different groups. Core microbiome analysis revealed that 12 core bacterial operational taxonomic units were associated with A. pruinosa in all seasons, seven of which varied with the seasons, changing between dominant and rare. Distance-based redundancy and variation partitioning analyses revealed that sea surface temperature was the major contributor of variation in the microbial community structure. We hypothesized that the high diversity and abundance of symbiotic bacteria and the increase in Prosthecochloris abundance in coral in summer can help A. pruinosa maintain its physiological functions, ameliorating the negative physiological effects of the decrease in Symbiodiniaceae density under high-temperature stress. Thus, the rapid reorganization of the symbiotic bacterial community structure and core microflora in different seasons may allow the corals to adapt to large seasonal environmental fluctuations. In conclusion, seasonal variation of bacteria plays an important role in coral adaptation to large environmental fluctuations.

Bioecology of coral reef in Panjang Island of Central Java Indonesia

Coral reefs currently are suffered from natural factors along with increasing anthropogenic activity. Panjang Island, a small reef island located in Jepara Regency, may also be experiencing such conditions. Therefore, this work was aimed to observe the condition of the coral cover of Panjang Island. Line intercept transect was applied to survey the coral cover and mortality index from fourteen stations. Insitu data consisted of the bottom substrate composition of the reefs and the physical parameters of the sea. The secondary data, i.e. coral reef area maps from 2001 to 2019 were taken from Landsat Image 7 and 8, data of wind were obtained from www.ogimet.com, while tidal data were collected from BMKG. The bathymetry was determined from the Geospatial Information Agency data, salinity global analysis forecast Phy 001.024 (CMEMS). Sea surface temperature (SST), and chlorophyll-a distribution were analyzed using ENVI software. The result showed that Panjang Island has a poor to the moderate condition of hard coral. Two out of six categories of abiotic and dead coral were found to be high. The mortality index of coral was in the high category (average 0.52). During research periods the sea waters were characterized by high sea surface temperature (29.34-30.94°C), chlorophyll-a was also tended to be high (0-2.65 mg.m-3), and an average of salinity was high 32 ‰. The weak currents came to all sides of the island, therefore the coral reef was not exposed to extreme currents. The waves came from the east, then the energy decreases after being blocked by coral reefs on the eastern side of the island, so that coral reefs in the northeast and south sides were safer to be exposed. The results suggest that hydrodynamic ecology directly or indirectly affected the percentage of coral cover and mortality index at the reefs of Panjang Island.

Air‐Water Exchange and Gas‐Particle Partitioning of Polycyclic Aromatic Hydrocarbons (PAHs) in Coral Reef Areas of the South China Sea

AbstractIn this study, we collected gas, particulate, and surface water‐dissolved phase samples from 16 sites in the South China Sea from March 21 to April 12, 2018. Thereafter, all the samples were analyzed for the air‐water exchange and source apportionment of polycyclic aromatic hydrocarbons (PAHs). Thus, it was observed that the overall PAH concentrations in the water and gas phases were 8.0 ± 5.5 ng/L and 41.3 ± 24.7 ng/m3, respectively. Back trajectory simulation showed that the air masses in the South China Sea primarily originated from mainland China during the heating period, and air‐water exchange analysis showed net deposition from air to water, with fluxes ranging from −5.53 to −89.72 ng/m2/d. Further, the logarithmic gas‐particle partitioning coefficient (logKp) of the PAHs regressed linearly with the logarithmic subcooled liquid vapor pressure (log P0 L), with an average slope of −0.3 ± 0.13.

Spatial analysis of geophysical and environmental factors characterize distinct coral reef habitats around Sri Lanka; implications for management

Spatial distribution patterns of coral reefs are maintained by a magnitude of chemical, physical and biological factors. Being a small continental island in the Indian Ocean, the extent of coral reef habitats around Sri Lanka has been limited and patchy showing unique, regional distribution patterns owing to these factors. However, the available data on these factors are sparse and outdated hindering proper management implications of these coral reefs. Here, we use remote sensing data on coral reefs in providing a framework to formulate hypotheses about the ecological processes governing these spatial and temporal patterns of coral reef distribution around the country. The results explained that the coral reef habitats around Sri Lanka are mostly shaped by the variation in nutrient levels (phosphate, nitrate and silicate), annual variance in sea surface salinity, mean current velocity and bathymetric shape. The study identified four unique coral reef areas around the island owing to variations of these factors; east coast reefs, south coast reefs, west coast reefs and north/northwestern reefs around Jaffna peninsula and Gulf of Mannar. The predicted Maximum entropy distribution models for the coral reef habitats of Sri Lanka revealed a significant amount of coral reef cover around the island (~2739 km2) which might deplete by ~4% in another 30 years due to changes in these factors. The highest amount of loss will be in the west coast (~17.76%) and least amount of loss will be in the east coast (~5.54%). The current research aids in understanding the reef ecology around Sri Lanka and provides implications for marine ecosystem management and conservation planning.

Coral Reef Coverage and Reef Fish Abundance in Menyawakan Island, Karimunjawa

Karimunjawa is one of the National Parks in Indonesia, a marine conservation area known for its diverse coral reefs, and mangrove forest. This study aims to determine coral reef status in Menyawakan Island at the northwest part of Karimunjawa Archipelago. Coral coverage as well as reef fish data were collected from the South, West, North, and East side of Menyawakan Island. Surveys were conducted at a depth of 5 and 10 meters, using the Line Intercept Transect (LIT) for coral coverage and visual census for reef fish abundance. The highest coral cover, categorized as good condition, was found in the North side of Menyawakan Island at a depth of 5 m (64.94%). Pomacentrus shows the greatest abundance with 291 individuals on the South side of Menyawakan Island. Overall coral cover in Menyawakan Island is categorized as medium to good condition, while the highest reef fish abundance is dominated with family of Pomacentridae, which are native habitat in coral reef area.

Diversity, composition, and abundance of zooplankton in the waters of Morella, Central Maluku, Indonesia

Generally, conditioning of surrounding waters caused variability of the diversity, composition and abundance of zooplankton organism, therefore, this research conducted during the rainy season (July 2019) in the waters of Morella. The zooplankton weekly collected using zooplankton net at three stations for the three weeks (periods). Each station is water with different ecosystem and conditions (sea grass, coral reefs and recreation area in coral reef area). 29 genera of zooplankton were encountered, which consisted of 25 genera of holoplankton and 4 genera of meroplankton, The copepods dominated the group of holoplankton, and reached the average value of 4708 individuals/m3. The highest abundance of the zooplankton reached the numbers of 19047 individuals/m3 (St 1, first period), while the lowest was 2547 individuals/m3 (St. 3, third period). Diversity indices (H’) was in a range of 2.717-3.004, whilst the Evenness indices was ranging from 0.82-0.89 and the highest similarity indices was between station 1 and 3 (92.0%) and the lowest was between station 2 and 3 (83.64%). The Siphonophores species, Diphyes sp was the only genera, which found at station 3 from the whole periods of this research.

Marine ecotourism development in South Sulawesi, Indonesia

Ecotourism is a fast growing tourism industry. Ecotourism is superior to other tourism because it can give economic benefits and preserve natural resources. The potential of Indonesian ecotourism, especially South Sulawesi has not been optimally utilized; therefore it is necessary to study its development potential. This study aims to analyze the potential and problems in marine ecotourism development in South Sulawesi. The study was done at Selayar Regency, Takalar Regency, Makassar City, and Pangkep Regency. The area of mangrove, coral reefs and sea grass ecosystem was estimated by using Landsat 7 Image and ArcView program. Other data were collected by using survey, census, interviews, and questionnaire. The parameters observed were coastal ecosystem resources; socio-economic; infrastructure; policy; and micro, small, medium business and co-operative. SWOT analysis was used to analyze the strategic condition; and Analysis Hierarchy Process was used to analyze the interaction between the priorities level. The study revealed that marine ecotourism development problems were low capacity resources management, low local community participation, limited infrastructure availability, weak capacity of local community institutions, and insufficient local community support or contribution. Marine ecotourism development in South Sulawesi should be focused on tools improvement of sustainable use, infrastructure development, socioeconomic strengthening, and consistent policy implementation.

A Study of Fauna Assemblages and Their Relation to the Sediment Accumulation in the Coral Reef Area, NW of the Arabian Gulf

The discovery of coral reefs in Iraqi marine waters is a new event in 2012 and it covers an area of approximately 28 km2 at the southern end of Khor Al-Amia. A team of divers from the German Freiburg Institute for Mining and Technology and Marine Science Center at the University of Basra were able to find coral reefs in the NW part of the Arabian Gulf. The aim of this article is to study fauna assemblages and try to understand the relationship between the accumulation of sediments and fauna assemblages in the Coral Reef area NW of the Arabian Gulf, southern of Iraq. Four surface samples of sediments of the area were studied and determined the relationship between the types of texture and the amount of fauna and shell fragments. Mollusca was chosen from among the existing groups of fauna due to the great number of species and large sizes, also Bryozoa studied in the region. The sand texture is predominant in the sediments of the area and the sand ratio was between 55-97% most of their grains are fine and round. The sediments of the region were distinguished by a high percentage of shells between 24–69% from the total percentage of sand. The phenomenon of multiple colors of sand and fauna revealed this due to the presence of minerals and oxides, impurities and pollution in the region, and genetic factors concerning fauna. Many species were diagnosed in the sediments of the region, reaching 62 species of Mollusca and Bryozoa. Mollusca is classified into three types (Gastropod, Pelecypoda and Scaphopoda). Some species were recorded for the first time in the region such as Japonactaeonpusillus, Cylichna cylindracea and Cuna majeeda.