Dinoflagellates from the genus Symbiodinium form symbiotic relationships with many marine invertebrates, including reef-building corals. Symbiodinium is genetically diverse, and acquiring suitable Symbiodinium phylotypes is crucial for the host to survive in habitat environments, such as high-light conditions. The sensitivity of Symbiodinium to high light differs among Symbiodinium phylotypes, but the mechanism that controls light sensitivity has not yet been fully resolved. In the present study using high-light-tolerant and -sensitive Symbiodinium phylotypes, we examined what determines sensitivity to high light. In growth experiments under different light intensities, Symbiodinium CS-164 (clade B1) and CCMP2459 (clade B2) were identified as high-light-tolerant and -sensitive phylotypes, respectively. Measurements of the maximum quantum yield of photosystem II (PSII) and the maximum photosynthetic oxygen production rate after high-light exposure demonstrated that CCMP2459 is more sensitive to photoinhibition of PSII than CS-164, and tends to lose maximum photosynthetic activity faster. Measurement of photodamage to PSII under light of different wavelength ranges demonstrated that PSII in both Symbiodinium phylotypes was significantly more sensitive to photodamage under shorter wavelength regions of light spectra (<470 nm). Importantly, PSII in CCMP2459, but not CS-164, was also sensitive to photodamage under the regions of light spectra around 470–550 and 630–710 nm, where photosynthetic antenna proteins of Symbiodinium have light absorption peaks. This finding indicates that the high-light-sensitive CCMP2459 has an extra component of photodamage to PSII, resulting in higher sensitivity to high light. Our results demonstrate that sensitivity of PSII to photodamage differs among Symbiodinium phylotypes and this determines their sensitivity to high light.

Despite the high number of victims every year, Physalia physalis’s envenomations in Indonesia are scientifically unsounded. This annual event occurred mainly in Java’s southern beaches and the Eastern Bali Islands, which are the most tourist destinations. The lack of scientific reports can lead to unaware and uneducated beachgoers resulting in a high number of victims, which in turn may ruin the economic sectors. Thus, this study aimed to report P. physalis’s envenomation and its treatments in the southern beaches of the Special Region of Yogyakarta Province. It was based on the 15 beach lifeguards’ and the primary health care units’ reports in 2019–2020. The envenomation cases varied among beaches and years, whereas the highest number of cases were reported in the most popular beach (Parangtritis beach). The partial beach closing due to the pandemic COVID-19 caused the number of cases in 2020 was slightly lower than that in 2019. The envenomations’ general symptoms were oedema and local pain that were treated with 5% food vinegar and hot water, if available. The severe cases (dyspnoea, nausea, vomiting, and cephalgia) were only reported twice in 2019. They were hospitalised in primary health care units; however, many people still practise the traditional non-scientific treatments, particularly in a chaotic situation. Despite the high number of victims every year, Physalia physalis’s envenomations in Indonesia are scientifically unsounded. This annual event occurred mainly in Java’s southern beaches and the Eastern Bali Islands, which are the most tourist destinations. The lack of scientific reports can lead to unaware and uneducated beachgoers resulting in a high number of victims, which in turn may ruin the economic sectors. Thus, this study aimed to report P. physalis’s envenomation and its treatments in the southern beaches of the Special Region of Yogyakarta Province. It was based on the 15 beach lifeguards’ and the primary health care units’ reports in 2019–2020. The envenomation cases varied among beaches and years, whereas the highest number of cases were reported in the most popular beach (Parangtritis beach). The partial beach closing due to the pandemic COVID-19 caused the number of cases in 2020 was slightly lower than that in 2019. The envenomations’ general symptoms were oedema and local pain that were treated with 5% food vinegar and hot water, if available. The severe cases (dyspnoea, nausea, vomiting, and cephalgia) were only reported twice in 2019. They were hospitalised in primary health care units; however, many people still practise the traditional non-scientific treatments, particularly in a chaotic situation.

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.

Coral reef communities contain a wide variety of mutualistic associations none more important than the relationship between corals and their symbiotic dinoflagellates of the genus Symbiodinium sp., commonly referred to as zooxanthellae. The function of Zinc (Zn) as cofactor of several enzyme systems such as extracellular carbonic anhydrase (extracellular CA) which catalyzes the interconversion of HCO3− and CO2. Concentrations of dissolved Zn in oligothropic waters are often very low therefore may limit the growth of zooxanthellae and their ability to fix CO2 from seawater via the carbonic anhydrase. The aim of this research is to investigate the effect of various concentrations of Zn on the growth and extracellular CA activity in zooxanthellae. Cell density was monitored daily by enumeration with hemocytometer-type chamber (0.1 mm). Extracellular CA was measured in homogenized intact whole cell by a pH drift assay. Results revealed that Zn status strongly influences the growth rate and extracelullar CA activity in zooxanthellae. The specific growth rate and cell density increased two-fold whilst extracelullar CA activity increased 10.5 times higher than that in control with increasing concentrations of Zn from 0 to 80 nM, but decreased when Zn was over 80 nM. Under a concentration of 80 nM was not Zn limited culture, consequently the growth rate of zooxanthellae not dependent on CO2 concentration yet offset by extracelullar CA activity

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.

Selat Bali merupakan salah satu wilayah tempat terjadinya kenaikan massa air (upwelling) yang dapat meningkatkan sumber daya ikan. Hal ini membuat Selat Bali umunya dipergunakan sebagai zona penangkapan ikan. Hasil tangkapan ikan di Selat Bali umumnya bersifat fluktuatif tiap musim, salah satu penyebabnya adalah lokasi penangkapan ikan yang tidak tepat. Salah satu alat bantu yang dapat dipergunakan oleh nelayan guna menentukan lokasi penangkapan adalah fishfinder. Fishfinder ini mampu memberikan informasi yang cukup detail yaitu tentang kelimpahan, sebaran, ukuran dan posisi kedalaman renang ikan. Tujuan dari pengabdian ini adalah memberikan pengetahuan dan cara pengoprasian (pemasangan, penggunaan dan pembacaan data) fishfinder bagi nelayan kedonganan. Khalayak sasaran dalam pengabdaian ini adalah nelayan, kelompok nelayan dan pemiliki kapal kelurahan kedonganan. Metode yang digunakan adalah ceramah, praktek penggunaan fishfinder dan diskusi. Kegiatan Program udayana mengabdi yang mengangkat tema pelatihan penggunaan fishfinder bagi masyarakat nelayan berlangsung sangat baik dan memberikan informasi tambahan tentang sejarah, prinsip kerja, kelebihan, kekurangan, jenis-jenis, tehnik pemasangan dan praktek cara pengoprasian fishfinder. Hasil pengabdian ini juga menunjukkan adanya atusias yang tinggi oleh masyarakat tentang materi dan praktek yang disajikan yang ditunjukkan oleh adanya interaksi timbal balik saat kegiatan berlangsung. Kata kunci : Pelatihan, Fishfinder, Nelayan, Kedonganan, Praktek