Species diversity of Polychaete in coral reef ecosystem of Great Nicobar Island, India

Sponges are one of the most diverse benthos in the coral reef ecosystem. They have many morphological characters that are specific to species, and their existence is influenced by environmental conditions. The aims of this study are to observe the relationship between morphological and species diversity of sponges in coral reef ecosystem in the Lembeh Strait and investigate the most influential environmental factor on sponge diversity. The study was carried out between April and May 2013 at nine study sites. The methods used were belt transect and line intersect transect (LIT) installed parallel to the coastline at approximately 5-meter depth. Our study supports a positive correlation between the morphological diversity and species diversity of sponges. Many of the morphological growth types were specific to sites that have particular characteristics. The percentage of the live coral cover is not a critical factor for sponge diversity in the strait. Instead, dead coral with algae as a benthic category has a significant positive correlation with the morphological and species diversity of sponges. Conversely, rubble as a substrate type has a strong tendency to affect sponge diversity negatively. To conclude, it is important to maintain healthy reefs in order to sustain benthic communities that are valuable to ecological functions and societies. Keywords:sponges, diversity, coral reefs, Lembeh Strait

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Analysis of hard coral condition on coral reef ecosystem in Ternate Island

IOP Conference Series Earth and Environmental Science ◽

10.1088/1755-1315/890/1/012055 ◽

2021 ◽

Vol 890 (1) ◽

pp. 012055

Author(s):

R E Paembonan ◽

F Ismail ◽

S Baddu ◽

Najamuddin ◽

I Tahir ◽

...

Keyword(s):

Coral Reef ◽

Species Diversity ◽

Diversity Index ◽

Coral Cover ◽

Environmental Parameters ◽

Hard Coral ◽

Coral Reef Ecosystem ◽

Dominance Index ◽

A Value ◽

Reef Ecosystem

Abstract Hard coral is a type of coral building structure in coral reef ecosystems. Hard coral is a coral reef entity that plays an important function in a coral reef ecosystem, especially related to physical and ecological functions in shallow marine waters environment. This study aimed to study percentages of coral cover, species life form, diversity index, dominance index, and distribution clusters of hard corals based on environmental parameters around Ternate Island. Hard coral cover sampling was carried out systematically using the underwater photo transect (UPT) method. The number of sampling stations were 30 location points with 750 photos. The method used for analyzing ecological conditions of hard corals was coral point count with excel extensions (CPCe). Environmental parameters measured included salinity, temperature, pH, brightness level, and dissolved oxygen. The distribution of hard coral clusters was analyzed statistically using the classify-hierarchical cluster. Study results showed that coral cover percentages ranged from 19% to 93% with an average cover of 67%, species diversity range was 7 to 40 species with an average of 19 species, diversity index (H ') with a value of 1.14 to 6.02 with an average of 2.07, dominance index (D) with a value of 0.13 to 0.53 with an average of 0.23. The results of the analysis of the distribution of hard corals consisted of four clusters. The study also found that distribution of hard coral clusters in Ternate Island was related to substrate topography.

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THE COMPOSITION AND DISTRIBUTION OF BENTHIC FORAMINIFERA AT CORAL REEF ECOSYSTEM IN THOUSANDS ISLAND

Jurnal Ilmu dan Teknologi Kelautan Tropis ◽

10.29244/jitkt.v5i1.7741 ◽

2013 ◽

Vol 5 (1) ◽

Author(s):

Lumban Nauli Lumban Toruan ◽

Dedi Soedharma ◽

Kresna Tri Dewi

Keyword(s):

Coral Reef ◽

Human Activities ◽

Close Association ◽

Mesh Size ◽

Coral Reef Ecosystem ◽

Composition Distribution ◽

Benthic Foraminifers ◽

High Nutrient ◽

Binocular Microscope ◽

Reef Ecosystem

Composition and distribution of foraminifers are affected by human activities and have close association with coral reef ecosystem. The aims of this research were to investigate the benthic foraminifers’ composition and distribution in sediment of coral reef ecosystem. Eleven stations of Karang Bongkok, Pramuka, and Onrust Island were observed in this study. The sediments were taken from surface substrate up to 2 cm under the substrate. Samples were washed on sieve with mesh size 0,063 mm, and then dried in oven with 50°C of temperature for two hours. After separating from the sediment, the foraminifers were laid on foraminiferal slide and indentified using binocular microscope. The highest composition of symbiont-bearing foraminiferal assemblages which associated with reef ecosystem was in East Pramuka (78.17%) and the lowest was in South Onrust (21,83%). The opportunistic type had the highest composition in South Onrust (38.67%) and the lowest was in South Karang Bongkok. In west Pramuka had the highest composition of heterotrophic type (57.17%) and the lowest was in North Onrust (11.33%). Onrust Island was dominated by opportunistic type, indicating high nutrient. The highest amount of foraminifers’ taxa was found in Karang Bongkok with good coral reef coverage, while the lowest in Onrust facing with Jakarta Bay. Keywords: composition, distribution, benthic foraminifers, coral reef.

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