Screening of anti-Candida albicans metabolites produced by marine sponge-associated bacteria

This study selected bacteria with high anti-Candida albicans (CA) activity among ten bacteria isolated from marine sponges. Bacteria were cultivated using the basal medium to produce the extract. Minimum Inhibitory Concentration (MIC) microdilution broth was used as an anti-CA assay followed by TLC-direct bioautography to characterize their active compound with spray reagents. The bacteria determination was done by molecular approaches using Repetitive-Element Sequences-based-PCR (rep-PCR) and amplification of 16S rDNA partial gene sequences, continued with BLAST analysis. The four out of ten tested bacteria had high anti-CA compounds and were potentially to be produced on a larger scale using the basal medium, which was BYT5C4, BYT5C5, BYT1A, and BYT7, with MIC of 1 mg/mL against 7.5×106 CFU/mL CA. TLC-bioautography test results showed that all metabolites from each isolate had different Rf and types of metabolites. Rep-PCR test showed that four bacteria had a low similarity index, indicating that they were different species. Based on molecular identification results, the BYT5C4, BYT5C5, BYT1A, and BYT7 isolates are strictly related to Brevibacterium casei, Exiguobacterium profundum, Micrococcus lylae, and Bacillus firmus, respectively. The active metabolites identified in this study can be isolated to determine the active molecules and their inhibitory routes to fungal growth. It is worth noting that additional research might be conducted to compare the activity of each antifungal metabolite to the synergistic activity of numerous antifungal metabolites detected in plant extracts.

Marine plastic debris in Indonesia: Baseline estimates (2010-2019) and monitoring strategies (2021-2025)

Indonesia set the mission to reduce marine plastic debris by 70% between 2018-2025 with a global significance to support the UN Sustainable Development Goal 14.1. This short communication assesses marine debris baseline estimates in Indonesia before 2020 from available contributions and provides recommendations for monitoring marine debris mitigation between 2021-2025. Widely ranging model estimates of plastic debris released into seas highlight the roles of data source, the spatial resolution of models, and in situ data to provide representative baseline values. Recognizing the strengths and uncertainties of available contributions, model outputs converge on a baseline value of 0.52 ± 0.36 million tons (Mt) per year prior to 2020 in Indonesia, therefore setting a targeted reduced number of 0.16 Mt of marine debris releases in 2025. The Indonesian Institute of Sciences showed a preliminary value of plastic debris accumulation in beaches at 113.58 ± 83.88 g/m2 monthly or equivalent to 0.40 Mt/year by assuming plastic debris is most pervasive within 3 meters from Indonesia’s 99,093 km-long coastlines. It is important to distinguish that while river monitoring data informs land-based plastic debris releases, stranded beach debris represents a fraction of debris that is not present in the water column and bottom sediments. Moving forward, monitoring initiatives to mitigate marine debris should leverage on nationwide municipality-level model estimates (e.g., the source to leakage route framework of the National Plastic Action Partnership) as well as in situ river and coastal particularly but not limited to sites co-identified in previous monitoring studies (i.e., Medan, Batam-Bintan, Padang, Jakarta-Seribu Islands, Semarang, Pontianak, Bali, Lombok, Makassar, Manado, Bitung). The latter should be conducted at least seasonally, considering evidence of monsoonal variations of marine debris release and accumulation in Indonesia. Indonesia's vastness and regional diversity require coordination among stakeholders (government agencies, research institutions, universities, NGOs, citizen scientists) to monitor progress in the environments.

Aggregates in aquatic ecosystems and implications for aquacultures

Agglomerations of suspended particulate matter serve various roles in aquatic ecosystems. They participate in nutrient and energy fluxes and are involved in important food web processes. While comprehensive studies on aggregates are available from natural freshwater and marine ecosystems, little is known about the roles of aggregates in aquacultures, particularly in shrimp pond farming. As particle-rich systems, shrimp ponds and marine aquaculture (mariculture) areas constitute interesting objects for aggregate studies, particularly as a source of natural feed, particle fluxes, microbial communities, including pathogenic bacteria, and possible vector of disease widespread. The aims of this review are i) to compile the current knowledge on the role of aggregates in aquatic ecosystems, particularly in aquaculture areas covering advantages and negative side effects of aggregates in aquacultures, ii) to explore the role of aggregates in disease ecology, and iii) perspective of aquaculture management in the context of aggregate utilization and management. Since Southeast Asia, especially Indonesia, is among the most important regions for aquaculture activities, this review focuses on Indonesian aquacultures. Although aquacultures produce important amounts of aggregates, including its associated microbial communities, they are rarely investigated in Indonesian aquacultures, particularly in shrimp pond farming. In contrast, most of the studies focused on bacterial cultivation and utilization of isolates for aquacultures. Thus, understanding the ecological roles of aggregates in aquacultures may support the improvement of aquaculture management and yields.

Climate variability since last glacial maximum based on distribution of foraminifera in North Papua Waters, Pacific Ocean

Foraminifera distribution is one of the proxies used to reconstruct climatic conditions and paleoceanography. Specific species or groups of foraminifera can be associated with certain oceanographic parameters. As one of the entrances of Indonesia Through Flow (ITF), North Papua Waters has the role of channeling water masses from the Pacific Ocean to the Indonesian Waters. It is also influenced by global thermohaline circulation and ENSO. In this study, observations were made of changes in the distribution of foraminifera to reconstruct paleoclimate and paleoceanographic conditions in the North Papua Waters and their relation to global climate conditions. The analysis was performed on 246 cm core sediments with eight cm foraminifera observation intervals at sample depths 246-126 cm and four cm at sample depths of 126-0 cm. Pulleniatina spp., Neogloboquadrina spp., and Globorotalia spp., are used for radiocarbon dating. Planktonic abundant species of foraminifera are Pulleniatina obliqueloculata, Neogloboquadrina dutertrei, Globorotalia menardii, Globigerinoides ruber, Globigerinoides trilobus, and the benthonic are Melonis pompilideus, Pullenia bulloides, Oolina sp., Planulina bradyii, Oridorsalis umbonatus, Cibicides subhaidingerii, Eggrela bradyii, Planulina wuelestroffi, and Quinqueloculina spp.,. Division according to cluster analysis can show the difference between Holocene and Pleistocene, which is then more detailed divided into 17 clusters. Based on biozonation there are some events that can be observed: climate variability since Late Pleistocene, record Pleistocene-Holocene boundary based on the significant variability of foraminifera distribution, and records some of the global climate events such as Last Glacial Maximum (~19-17 kyr), Younger Dryas (~11-9 kyr), and 8,2K event.

Are they always bad? Assessing benefits of non-indigenous species in aquatic environment and their implications

Non-indigenous species (NIS), non-native, or alien species are any organisms living and spreading outside their natural habitat. Many of NIS spread to a new environment accidentally, while some other species are intentionally introduced by humans to a new habitat in many different pathways, as follows: 1) release; 2) escape; 3) contaminant; 4) stowaway; 5) corridor; and 6) unaided. Threaten native biodiversity may be the most problematic impact of NIS. They can also disrupt food-web organizations and affect the ecosystem structures. Additionally, the problem is exacerbated by disagreements regarding whether or not NIS should be permitted for aquaculture production. The likelihood of NIS escaping, being released from aquaculture, and establishing in its native habitat poses a significant threat to the ecosystem and biodiversity. NIS also have positive impacts as ecosystem engineers which may increase the biodiversity of native communities. Other benefits of NIS include providing an alternative food source and supporting fisheries and aquaculture sectors. Understanding the introduction process and the impacts of NIS should be supported by effective policy frameworks and management approaches, including risk assessment, prevention and control, pathway and vector management, early detection and rapid response, eradication, and mitigation and restoration. Furthermore, the crucial efforts would be raising public awareness, improving scientific research, and developing strategy regarding biosecurity issues as consequences of the emergence of interactions complexity among NIS and other global ecological change drivers.

Physiological response and growth performance of spiny lobster (Panulirus homarus) juvenile rearing in recirculating aquaculture system with various shelter type

Spiny lobster nursery is done to produce more adaptive and uniform juvenile lobsters quality. Shelters used in spiny lobster nursery served to reduce physical contact among lobsters in the rearing tank. The purpose of this study was to analyze the effect of different shelter types on physiological response and growth of spiny lobster (Panulirus homarus) juvenile rearing in recirculating aquaculture systems. Lobsters with an average weight of 50.07 ± 2.89 g were reared for 60 days. They were fed once a day with trash fish. The daily feeding rate was 3-4% of total weight. This study used four types of shelter as treatments with two replications. PVC pipe shelter as control (K), individual shelter square shaped (IS ■), individual shelter triangle shaped (IS ▲), and individual shelter tube shaped (IS ●). The weight and length of the lobster carapace improved with the duration of the research in all treatments. Throughout the trial, glucose levels in controls were generally greater than those in specific shelf treatments. The reaction of lobster hemolymph total protein to different shelters is highly variable. Overall, the usage of individual shelters had a considerable positive influence on grown lobsters in this study. This is because individual shelter eliminates contact between lobsters, eliminating the possibility of cannibalism in the cultivation container. This study concludes that IS ■ used in rearing Panulirus homarus showed a lower stress response than the other treatments in terms of glucose and total protein lobster hemolymph during the study. IS ■ is the best because it reduced stress levels and yielded better total biomass among the other treatments.

Health status of blood cockle's Tegillarca granosa (Arcidae: Bivalva) from three different farms along the Strait of Malacca

The annual production of Tegillarca granosa in Perak and Selangor is constantly decreasing since 1996, however a different production pattern was reported in Johor where it was fluctuated for the past years. Thus, this study was done to provide information on the health condition of T. granosa through morphological observation of the biological attributes and the anatomy of the gill’s tissue. Sampling work was done in dry seasons between May and July 2019 at Bagan Pasir Laut, Perak, Kuala Sungai Buloh, Selangor and Sungai Ayam, Johor. A group of 22-30 T. granosa were collected randomly from each site for biological attribute measurement and the mean were analyzed using Kruskal-Wallis. Six to seven cockles with shell length ranging 25.00 – 35.00 mm were selected for the gill’s histological observation. Fresh T. granosa samples were preserved in 10% formalin before dissection and then the gills were fixed in Bouin's solution, followed by histological standard procedures and haematoxylin and eosin staining. Results indicated a significant difference of biological attributes was detected between the sites with the lowest measurement found in samples from Bagan Pasir Laut. The highest body weight (14.08g) was found in samples from Kuala Sungai Buloh, followed by Sungai Ayam (10.81g) and then Bagan Pasir Laut (8.08g). The histology of the gill filaments of samples from Sungai Ayam are full of hemocytes, well-structured epithelium cells with cilia in comparison to samples from Bagan Pasir Laut, and Kuala Sungai Buloh. The most degenerated gill filaments were found in samples from Bagan Pasir Laut. Thus, suggesting the unhealthy condition of the gills, affects the shell sizes and body weight of T. granosa between the three established farms.

Correlation between macroalgae diversity and water quality in Southwest Maluku waters

Macroalgae play an important role in the ecosystem of the coastal area, serving as a shelter ground, nursery ground, and feeding ground. Macroalgae communities are directly influenced by water quality. This study aim was to determine the correlation between the macroalgae diversity and water quality in southwest Maluku waters. This research was conducted in September 2019 at seven research stations. Macroalgae samples were collected by transect method, while seawater quality was measured using Van Dorn Water Sampler. The macroalgae diversity, species composition, and dominance were determined. Water quality parameters analyzed were temperature, salinity, pH, phosphate, nitrate, and ammonia. Correlations between macroalgae diversity and water quality were determined using principal component analysis. This study recorded 45 species of macroalgae consisting of 15 species of red algae (Rhodophyta), 6 species of brown algae (Phaeophyta), and 24 species of green algae (Chlorophyta). Diversity Index varied ranged from low to moderate categories (0.969 - 2.345). Water quality in general is still quite good for macroalgae life. Macroalgae diversity and water quality correlate and influence each other.

Effects of F/2 media modification on growth and antioxidant activity of microalga Nannochloropsis oculata

Nannochloropsis oculata is a common microalga that can be found in marine water. One of the most commonly used media for microalga culture is F/2 media; however, the optimum F/2 media composition for N. oculata growth is rarely informed. Therefore, the aims of this study are to determine the effect of F/2 medium modification on the growth of N. oculata and the antioxidant activity of N. oculata. This study consists of several procedures including; cultivation, growth observation (cell density and biomass), extraction, and antioxidant activity of N. oculata extracts. The highest growth (cell density and biomass) of N. oculata was found in media F/2 + 0.5 ml, while the lowest was in media F/2 - 0.5 ml. The strongest antioxidant activity of N. oculata was found in media F/2 + 1 ml, and the lowest was in the media F/2 - 0.5 ml. Media modification gave different results on cell density, biomass, and antioxidant activity of microalgae N. oculata.

Community structure and condition of seagrass meadows in Ayau Islands, Raja Ampat Regency

Seagrass meadows are an important component of coastal ecosystems, providing many ecosystem services beneficial for human well-being. Basic information about seagrass meadows in Indonesia is relatively limited, particularly in the eastern part of Indonesia, such as the remote Ayau Islands in Raja Ampat. In this paper, we reported the community structure and condition of seagrass meadows in Ayau Islands surveyed during Nusa Manggala Expedition in November 2018. We conducted the seagrass survey using quadrat transect method at five locations, i.e. Reni, Rutum, Abidon, Kanober, and Dorehkar. In the survey, we assessed parameters of community structure, including habitat extent, species composition, seagrass cover, seagrass density, macroalgae and epiphyte cover. We also recorded environmental parameters, i.e. substrate types, water clarity, salinity, water temperature, and nutrient (phosphate and nitrate). Our study showed that seagrass meadows in Ayau Islands are multispecies meadows, composed of two to five species. In overall, five species recorded in Ayau Islands are Cymodocea rotundata, Enhalus acoroides, Halodule pinifolia, Halophila ovalis, and Thalassia hemprichii. The most common species is T. hemprichii as it can be found in all locations. Meadows in Reni, Rutum, and Dorehkar are in a healthy condition, while in Abidon and Kanober are in less healthy condition. This information is of significance as baseline information needed for seagrass conservation planning.