Widiastuti Widiastuti

Biogeographic patterns for marine fishes and scleractinian stony corals are well-established, but it is still unclear whether these patterns apply to the understudied marine invertebrates. Here we investigate the distribution of zoantharians (=zoanthids), an order of cnidarians that are distributed globally from tropical coral reefs to deep temperate oceans. We examined the available literature, along with new records and morphological and DNA sequence data, to establish their first global biogeographical assessment. Two striking results emerged that contrast with previously known marine biogeographical patterns. The first was that several zoantharian genera are cosmopolitan, inhabiting most biogeographic provinces within and between ocean basins. Although the highest diversity was observed in the Indo-Pacific Ocean (IPO), concordant with biogeographic assays of reef fishes and stony corals, the distribution of genera was not significantly different between the Atlantic (ATO) and the IPO. Secondly, there were multiple sibling species complexes between the ATO and the IPO. At species and population scales, a long pelagic larval duration, asexual reproduction modes, and rafting abilities, may at least partly explain the low levels of genetic differences between ocean basins. As some zoantharian species can play a significant role in phase shifts, filling knowledge gaps on species distributions is essential to support monitoring of reef ecosystems. Our study revealed that several Zoantharia genera, and most families, are globally distributed. This is highly distinct from the pattern previously observed for common reef animals, such as stony corals and fishes, where the Indo-Pacific Ocean has several times the number of familes/genera compared to the Atlantic Ocean. Some zoantharian species, especially in the genera Palythoa and Zoanthus , have dispersal strategies that allow for broad distributions within ocean basins, while the vicariant events of the rise of the Isthmus of Panama and the appearance of the Benguela upwelling likely prompted the speciation of sibling lineages between the oceans.

A new species of Cladocoryne Rotch, 1871, C. spongicola sp. nov., a hydroid strictly associated to a host demosponge, is described from shallow waters in the NE of the island of Bali, Indonesia. Its cnidome lacks the distinctive elliptic macrobasic euryteles of the substrate generalist C. haddoni Kirkpatrick, 1890, retaining only the elongate counterpart, common to most species of the genus. Its gonophores are eumedusoids with four marginal bulbs, a canal system, and four basal interradial nematocyst pads. A morphological comparison with its congeners is provided. A multilocus (16S, 18S, 28S rRNA and COI) phylogenetic analysis confirms its divergence from C. floccosa Rotch, 1871 and C. haddoni, two of its congeners for which sequence data are available so far.

This research examines the function changes around the coral reef ecosystem caused by coral disease in Paraja Bay. The research aims to identify coral disease and the correlation between diseases and reef coral species. These identifications of coral diseases can be used to assess corals’ growth process, reproduction, and structural changes. The in-situ data was collected in February 2022 at 16 stations on each side of four small islands. The closeness relationship analysis was performed using PCA and XLstat. The results show that the disease prevalences in four small islands are varied, namely Badul Island (17.2%), Mangir Island (6.96%), Oar Island (2.66%), and Umang Island (4.86%) with an average of 7.91%. The coral diseases found in all stations were Trematodiasis and White Syndrome. Corals with Trematodiasis symptoms were Favia sp., Favites sp., and Platygyra sp., while ones with White Syndrome were Acropora sp., Favites sp., and Pavona sp. The existence of the diseases indicates the need for ecosystem restoration to include environmental aspects and community activities. This restoration action can accelerate the process of habitat and associated biota recovery.

Widiastuti, Borumei D. 2024. Indication of feeding ground inside the Manta Ray's cleaning station by investigation of the zooplankton community composition in Raja Ampat Islands, Indonesia. Biodiversitas 25: 1239-1245. Raja Ampat Islands, Indonesia, hosts reef manta ray (Mobula alfredi) and oceanic manta ray (Mobula birostris). Studies reported that these areas have functioned as manta ray cleaning and nursery sites. However, food availability is also the main attraction for manta ray aggregation. Thus, this study investigated the zooplankton community composition and abundance in the Manta Sandy Spot, a manta's cleaning station, to indicate its other role as the manta ray's feeding ground. Three sampling sites were located around the cleaning station bordered by mooring. A plankton net collected samples with a 100 µm mesh size, a mouth diameter of 30 cm, and a 1 m length horizontally towed from a boat for 5-10 min at a speed of ~2 knots. Manta ray's behavior was observed by snorkeling in the surface waters. Results demonstrated that the zooplankton was only composed of Copepod, consisting of three orders: Calanoida, Cyclopoida, and Harpacticoida. Among these orders, Calanoids dominated the zooplankton composition (93%). These genera were further grouped according to their body sizes, whereas three genera in Calanoids (Eucalanus, Calanus, and Undinula) were categorized as large-bodied zooplankton. The presence of the large-bodied zooplankton in the water samples, Calanoids, and Cyclopoids, which have been reported as the manta rays' preferred prey, indicates the area's role as the manta ray's feeding ground. This finding is supported by studies that found these zooplankton in the water where manta rays' feeding activity occurred and were absent in areas with no feeding activity. More indications were demonstrated by the manta ray's behavior, which followed the feeding activity criteria.

Bakteri Vibrio parahaemolyticus dan V. campbellii merupakan penyebab infeksi vibriosis pada berbagai organisme budidaya laut, salahsatunya adalah Udang. Selain itu, bakteri Aeromonas hydrophila merupakan patogen penyakit Motile Aeromonad Septicaemia (MAS). Oleh karena itu, diperlukan suatu upaya untuk menghambat aktivitas bakteri. Penelitian sebelumnya menunjukkan bahwa ekstrak rumput laut Kappaphycus alvarezii dapat menghambat pertumbuhan bakteri, baik itu bakteri gram negatif maupun gram positif, tetapi aktivitas antibakteri terhadap bakteri Vibrio parahaemolyticus, V. campbellii dan Aeromonas hydrophila belum diketahui. Penelitian ini bertujuan untuk menganalisis aktivitas antibakteri dan nilai konsentrasi daya hambat minimum dari ekstrak K. alvarezii terhadap bakteri V. parahaemolyticus, V. campbellii dan A. hydrophila. Rumput laut K. alvarezii diperoleh dari hasil budidaya di kawasan Pantai Geger, Kabupaten Badung. Metode yang digunakan untuk pengujian aktivitas antibakteri yaitu difusi agar. Ekstrak K. alvarezii dalam metanol dengan konsentrasi berbeda (10, 5, 1, 0,05%) diteteskan pada kertas cakram dan diletakkan pada masing - masing kultur bakteri uji. Pengukuran zona hambat dilakukan setiap 6 jam sekali selama 24 jam masa inkubasi. Aktivitas antibakteri ditandai dengan terbentuknya zona bening di sekitar kertas cakram. Selain itu, digunakan Chloramphenicol sebagai kontrol positif dan metanol sebagai kontrol negatif. Hasil penelitian menunjukkan aktivitas antibakteri hanya terdapat pada bakteri V. campbellii yaitu sebesar 12,5 mm dengan konsentrasi hambat minimum ekstrak yaitu sebesar 10%.

Mariculture is considered a future economic source for Indonesia. However, this practice may degrade the surrounding ecosystem by decreasing the water quality, including the plankton community. This study aimed to determine the community structure of plankton (phytoplankton and zooplankton) in the mariculture sites. Study sites were selected based on the mariculture activities of the Research Center for Marine and Terrestrial Bioindustry (PRBILD-BRIN) located in Kodek Bay, Lombok Island. Samplings were conducted in February 2021, zooplankton samples were collected horizontally by towing a 100 μm plankton net using a boat, whereas phytoplankton was collected using a 20 μm plankton net horizontally. The plankton samples were preserved with 4% formaldehyde, identified, and counted in a Sedgwick Rafter cell counter using an Olympus CX21 (10x). Results demonstrated that zooplankton was dominated by genera from the Subclass Copepoda (Temora sp., Microsetella sp., Euterpina sp., Oithona sp., Acartia sp., and Onceae sp.) that were significantly more abundant at Sites 1 and 2 than those at Sites 3 and 4. The diversity levels were moderate at all sites, except at site 1, which Temora dominated. Phytoplankton was mainly composed of Bacillariophyceae, followed by Dinophyceae, Chlorophyceae, and Conjugatophyceae, with no significant difference in abundance at all sites. The diversity levels were low for all phytoplankton taxa at all sites except at site 2, where Bacillariophyceae and Dinophyceae equally composed the community. It is suggested that the mariculture organisms may shape these phytoplankton and zooplankton community structures by recycling particular nutrients.

Celukan Bawang water has a strategic location in the northern part of Bali Island that threatened its surrounding coral reefs by shipping, power plant, industrial activities, and shrimp ponds. However, there is limited data on its biodiversity status. Therefore, it is necessary to provide factual information regarding the coral reef ecosystem condition in scientific data. This study aimed to measure the coral reef`s components and the community structure. The coverage of coral reef components was collected based on the UPT method, while community structure data was taken in a belt transect within two different sites. All data was collected in December 2020. The difference in coral reef ecosystem components among sites was analyzed with the Paired-T and Kruskal-Wallis tests (for the non-homogenous data). Results showed that the coverage of live coral colonies in Site 1 is categorized as poor, whereas Site 2 is classified as moderate. Reefs were dominated by type growth non-Acropora massive from the family of Faviidae and encrusting from the family of Pocilloporidae. Statistically, there were no significant differences in all coral reef ecosystem components among Sites 1 and 2. Diversity and Evenness Indices were similarly low in the two sites. Dominance Index demonstrated that Site 1 was lower than Site 2 (moderate). It might be related to the coverage of the abiotic component, which, despite being statistically insignificant, showed that Site 2 has a higher percentage of rubbles and rocks. Rubble and rock can be a substrate for the coral juvenile to attach.Keywords: Community structure; Coral reef; Celukan Bawang; Buleleng

Hard coral is the main constituent of the coral reef ecosystem and functions as shelter, nursery, and feeding ground for various marine macro- and microbiotas, such as bacteria in its mucus. Coral as the host may benefit from this partnership or receives detrimental effects since bacteria may turn into parasitic or pathogenic. Coral A. hyacinthus can be transplanted for ornamental coral. However, it is vulnerable to be infected by coral disease due to pathogenic bacteria if the water quality is poor. Therefore, this study was aimed to determined the community composition of bacteria associated with coral A. hyacinthus mucus. Corals A. hyacinthus were collected from the traditional coral transplantation in Patas village, Gerogak District, Buleleng Regency. Mucus were sampled from ± 5 cm fragment from 3 different coral colonies. Isolates were cultured in the Nutrient Agar medium. The identification of bacteria isolates was according to Biochemical Tests for Identification of Medical Bacteria 2nd edition. The identification of the isolates consisted of morphological and biochemical tests. The identification results found 10 isolates that consisted of Micrococcus sp. Pseudomonas sp., Flavobacterium sp. and Vibrio sp. However, the composition varied among the coral colonies.

Symbiotic corals are not only with zooxanthella but also with various microorganism communities, namely bacteria. The presence of bacteria on the reef acts as a nutrient provider for coral animals. One of the adaptations made by corals to environmental changes is by secreting mucus. Mucus provides living space for various types of bacteria. Acropora coral is one of the largest and most extensive coral builders in coral ecosystems, adaptable, and has a fast recovery rate from coral bleaching. The aimed of this study was to determined the bacterial community associated with A. horrida coral mucus. Bacterial identification was based on observations of colony morphological tests and biochemical tests. The results of this study showed that 6 isolates of A. horrida coral mucus bacteria on average have a round shape with a complete border, flat elevation, and white with a smooth texture. The six bacterial isolates showed negative results where there were no bubbles. The oxidase test results showed 3 negatives with no change in color and 3 positives with a change in color to violet. In the gram staining test, there were 2 gram-negative isolates and 4 gram-positive isolates. Characteristics of the six bacterial isolates associated with A. horrida coral mucus identified include the Micrococcaceae, Lactobacillaceae, Clostridiaceae, and Rhizobiaceae families. It was suspected that these bacteria are opportunistic, where the density will increase if there are pollutants into coral reef ecosystems such as organic matter and nitrogen which can increase their growth.