BIOTROPIA, The Southeast Asian Journal of Tropical Biology (p-ISSN 0215-6334, e-ISSN 1907-770X), is a scientific publication of the Southeast Asian Ministers of Education Organization (SEAMEO) Southeast Asian Regional Center for Tropical Biology (BIOTROP). It publishes articles in the broad areas of tropical ecosystems and environmental impacts, biodiversity conservation and sustainable development and biotechnology. Since 2012, BIOTROPIA has been indexed by SciVerse SCOPUS (Elsevier), CrossRef, DOAJ and Google Scholar. Articles published in the journal are papers reporting results of original research, reviews on specific topics not available elsewhere in up-to-date form, and short communication in which advances in knowledge of significance are briefly announced. Submission of paper is taken to imply that it has not been submitted to other journals and that, if accepted, will not be published elsewhere. All papers submitted for publication in BIOTROPIA are evaluated by subject matter experts and go through editorial revision. Authors may suggest names of potential reviewers. BIOTROPIA uses anonymous reviewing, in which the identities of authors and reviewers are kept confidential.
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ASSESSMENT OF ORGANIC PHOSPHORUS DISTRIBUTION IN THE SEDIMENT AND WATERS OF LANGAT RIVER
ARTICLE HIGLIGHTS - Langat River water and sediment quality deteriorate toward downstream. - Dissolved organic phosphorus increases near agricultural areas. - Sediment phosphate retention dominated by non-labile organic phosphorus. - Downstream pollution linked to sediment sorption and nearby agriculture. ABSTRACT The Langat River traverses rapidly developing urban areas in Malaysia and is significantly affected by anthropogenic activities. The introduction of excessive phosphorus into rivers poses a significant ecological issue. Water and sediments were sampled from nine stations at Langat River to evaluate the current and potential impacts of organic phosphorus. The water quality parameters indicate a progressive decline downstream, attributed to allochthonous sources from tributaries and land use practices, particularly agriculture. Inorganic substances are the principal cause of pollution in the river while degradation of organic pollution biologically is reduced. Dissolved organic phosphorus (DOP) plays a significant role at stations that are either relatively unpolluted or adjacent to agricultural areas, serving as a potential source of bioavailable phosphorus. The total organic phosphorus in the sediment increased downstream, predominantly comprising non-labile fractions (67–78%). The labile fractions exhibit strong correlations with dissolved oxygen (DO) (r = -0.797), dissolved organic phosphorus (DOP) (r = 0.931), and conductivity (r = 0.837), suggesting internal loading to the water column. Increased non-labile fractions indicate the sediment's capacity to retain organic phosphorus. The downstream stations exhibit elevated risk owing to high sorption capacity and proximity to agricultural sources of organic phosphorus.
Copyright (c) 2026 Micheal Rajaram, Muskhazli Mustafa, Nor Azwady Abd Aziz, Noor Haza Fazlin Hashim, Bashirah Mohd Fazli, Bilyaminu Garba Jega http://creativecommons.org/licenses/by-nc-nd/4.0
MICROBIAL DETOXIFICATION OF CYANIDE CONTENT IN CASSAVA WASTE:A SUSTAINABLE APPROACH
ARTICLE HIGLIGHTS - Cassava waste with cyanide contamination presents significant environmental and health hazards. - Cyanide hydratase, nitrile hydratase, and rhodanese are microbial enzymes essential in the degradation of cyanogenic compounds. - The efficiency of cyanide degradation during fermentation is influenced by pH, temperature moisture content, and microbial strains. ABSTRACT Cassava is a vital crop in tropical regions, known for its versatile applications in human and animal nutrition. Despite the potential of cassava byproducts, they contain cyanogenic glycosides such as linamarin and lotaustralin, which can hydrolyze to toxic cyanide, posing enormous environmental and health hazards. This review demonstrates microbial detoxification as an effective approach for mitigating cyanide contamination in cassava byproducts. Microorganisms such as Aspergillus, Bacillus, and Pseudomonas are known for their ability to detoxify cyanide via enzymatic mechanisms. These microorganisms facilitate β-cyanoalanine and rhodanese pathways that convert cyanide into non-toxic compounds. Comparative analysis of cassava waste fractions, leaves, peels, and bagasse showed that cyanide levels varied from 288.12 to 25.69 mg/kg, depending on processing, variety, and fermentation. This review highlighted the degradation of cyanide content from cassava waste via fermentation. The efficiency of submerged and solid-state fermentation processes can be affected by factors such as pH, temperature, microorganisms, and moisture content, achieving over 90% detoxification. However, solid-state fermentation offers a cost-effective, low-energy alternative, and submerged fermentation enhances microbial interaction for improved breakdown. Microbial methods offer a more environmentally sustainable alternative to chemical treatment, yet challenges related to scalability, optimization efficiency, and the necessity for resilient microbial strains remain. Nevertheless, the microbial degradation approach demonstrates significant potential for the biodegradation of cyanogenic compounds, offering a promising biological approach for detoxifying cyanide in cassava waste, reducing environmental pollution, and minimizing economic implications in waste valorization.
Copyright (c) 2026 Fatimah Ibrahim Jumare, Madihah Md Salleh , Nurashikin Ihsan, Huszalina Hussin, Dr Shafaatu http://creativecommons.org/licenses/by-nc-nd/4.0
OCCURRENCE OF POWDERY MILDEW CAUSED BY Podosphaera sp. ON INVASIVE WEED Ageratum houstonianum IN NEPAL
ARTICLE HIGHLIGHTS - First report of Podosphaera sp. on invasive Ageratum houstonianum in Nepal. - Pathogen identified by unique cask-shaped conidia, chasmothecia and fibrosin bodies. - Potential biocontrol agent discovered for managing this invasive weed. - This weed can act as a pathogen reservoir; monitoring is essential to protect nearby crops. ABSTRACT Ageratum houstonianum is an invasive annual weed in Nepal that grows in diverse habitats such as fallow areas, crop fields, and roadsides. This study reported a powdery mildew disease on this weed species, which causal agent was identified as Podosphaera sp. Pathogen identification was based on symptomatology and micromorphological observations. The pathogen was characterized by slightly dark, branched and septate hyphae with nipple-like appressoria; straight and unbranched conidiophore; hyaline and cask-shaped conidia with fibrosin-like bodies. Immature chasmothecia with mycelium-like appendages were also observed. The asci were ellipsoidal with a thin oculus. Based on the literature, the fungus was first reported in Nepal on Ageratum houstonianum. This report expands the known geographical distribution and host range of this powdery mildew pathogen in South Asia and highlights the pathogen as a potential biocontrol agent for this invasive weed. Additionally, A. houstonianum is common in agroecosystem, thus, it can serve as a reservoir of Podosphaera sp. facilitating spread to crop plants. Therefore, careful utilization, monitoring, and management of the pathogen are essential both to control the host weed and to limit the spread of pathogen to crops.
Copyright (c) 2026 Hari Sharan Adhikari, Lal Bahadur Thapa, Sanjay Kumar Jha http://creativecommons.org/licenses/by-nc-nd/4.0
MICROSATELLITE-BASED GENETIC VARIATION IN Rhizophora apiculata AND Rhizophora mucronata FROM EAST KALIMANTAN
ARTICLE HIGHLIGHTS - Microsatellite markers were used to study population genetic variation in Rhizophora - Molecular systematic analysis showed moderate genetic diversity with low heterozygosity - Population genetic structure was dominated by within-population variation (AMOVA) - Phenetic analyses revealed weak clustering among Rhizophora populations - Genetic patterns supported connectivity within Rhizoporaceae populations in East Kalimantan ABSTRACT Mangroves of the family Rhizophoraceae are pantropical, with the genus Rhizophora forming a major component of tropical mangrove ecosystems. Rhizophora apiculata and Rhizophora mucronata are widely distributed in the Paser region, Balikpapan Bay, and the Mahakam Delta of East Kalimantan, Indonesia. This study examined genetic diversity and population structure of both Rhizophora species using simple sequence repeat (SSR) markers. The results showed moderate genetic diversity but relatively low heterozygosity in both species. Most genetic variation occurred within populations, as indicated by AMOVA, while R. apiculata exhibited lower genetic differentiation among populations and lacked private alleles, and R. mucronata showed higher population differentiation and possessed private alleles, suggesting localized genetic variation. Cluster and principal coordinate analyses revealed extensive overlap among populations for both species, indicating weak population structure and ongoing gene flow across the study area. Overall, the findings suggest that populations of R. apiculata and R. mucronata in East Kalimantan function as genetically connected units rather than as strongly differentiated populations. These results highlight the importance of maintaining habitat connectivity and protecting genetically unique populations to support the long-term resilience and sustainable management of mangrove genetic resources in East Kalimantan.
Copyright (c) 2026 Adristi Shafa Widyasari, Abdul Razaq Chasani, Istiana Prihatini, Tri Atmoko, Mukhlisi, Burhanuddin Adman, Bina Swasta Sitepu http://creativecommons.org/licenses/by-nc-nd/4.0
HERPETOFAUNA DIVERSITY IN MID-SUCCESSIONAL FORESTS OF MT. BANAHAW DE LUCBAN, PHILIPPINES
ARTICLE HIGHLIGHTS - Active forest restoration via reforestation hastens forest cover re-establishment and recovers ecosystem health. - Due to the sensitivity of herpetofauna to environmental changes, they are a good indicator of ecosystem health. - This study compares herpetofauna diversity in reforestation areas and natural secondary growth mid-successional forests to determine the impacts of active forest restoration and conservation initiatives in promoting ecosystem recovery and health. - The results can assist decision makers in formulating sustainable forest and ecosystem health restoration strategies. ABSTRACT Herpetofauna are sensitive to environmental changes, making them good indicators of ecosystem health. This study assessed the diversity of herpetofauna species in the mid-successional forest consisting of 30-year reforestation areas and natural secondary-growth forests of Mount Banahaw de Lucban (MBdL) to determine the impacts of forest restoration and conservation initiatives in promoting ecosystem recovery and health. A combination of belt transects following forest trails and purposive sampling was employed where samples were captured via net or hand-picked. Results revealed 26 herpetofauna species composed of 11 amphibians and 15 reptiles, including snakes and lizards. These findings are significantly higher than previously reported. Herpetofauna had moderate diversity at 2.219 and 1.903 in the Shannon Diversity Index (H’) for amphibians and reptiles, respectively. Species richness (Ra) was 7.091 for amphibians and 3.533 for reptiles, with dominance (D) values of 0.110 and 0.260 and evenness (J’) values of 0.925 and 0.703, respectively. Using the Chi-square test for Independence, however, these differences between reforestation and secondary forest were found significant (X2 = 12.64, P = 0.002, d = 2) for species abundance but not for species richness. Platymantis banahao, P. luzonensis, Gonocephalus semperi, Boiga angulata, Ptyas luzonensis, and Malayopython reticulatus were threatened species. Results imply that the reforestation, forest protection, and conservation efforts for more than 30 years have increased forest cover, and improved ecosystem health favoring herpetofauna species.
Copyright (c) 2026 Ronald C. Garcia, Amalia E. Almazol, Dennis E. Pulan, Almar John A. Luna, Liam Karl C. Manago, Francisco N. Beltran, Eraldwin A. Dimailig, Daniel S. Galeon, John Louis S. Narinay, Gracelle L. Ann Zoleta, Judy Ann Develuz http://creativecommons.org/licenses/by-nc-nd/4.0
POPULATION ASSESSMENT OF JAVAN BELIDA FISH (Notopterus notopterus) IN RAWA PENING LAKE, CENTRAL JAVA, INDONESIA
ARTICLE HIGHLIGHT - Belida population in the lake is low and nearing threatened status. - Belida size data show weak population recovery. - Conservation action is needed to protect belida stocks. - Habitat pressure increases belida vulnerability and limits protection. - Findings support stronger conservation for threatened belida. ABSTRACT The conservation status of belida fish in Indonesia is regulated under the Minister of Maritime Affairs and Fisheries of the Republic of Indonesia Number 1 of 2021 concerning Protected Fish Types, which includes four species: Bornean Belida (Chitala borneensis), Sumatran Belida (Chitala hypselonotus), Lopis Belida (Chitala lopis), and Java belida (Notopterus notopterus). The Javan belida fish (Notopterus notopterus) is currently classified as Least Concern (LC) to facilitate data collection on protected fish species and those listed in the Appendices of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES). However, intensive harvesting for human consumption may lead to continued population declines in Java. Therefore, this study aimed to estimate the population size and status of the Javan belida fish, providing a scientific basis for government recommendations, particularly by the Ministry of Maritime Affairs and Fisheries, regarding its conservation status. Field sampling was conducted in situ in Rawa Pening Lake during three sampling periods (January, February, and March 2024) using bamboo blinds, traps, and lift nets. The collected data were analyzed to estimate population abundance, length-weight relationships, length-frequency distribution, sex ratio, gonad maturity stage, and catch per unit of effort. A total of 47 belida fish were caught, all identified as Javan belida (Notopterus notopterus). The estimated population density in Rawa Pening Lake was 32 individuals per 1,400 m2, equivalent to 229 individuals per ha. Based on the International Union for Conservation of Nature's (IUCN) vulnerability criteria, the belida population in Rawa Pening Lake is considered near threatened.
Copyright (c) 2026 Waluyo waluyo, Santoso Budi Widiarto, Anhar Muslim, Linggar Dirgantara, Alyaa Farah Qonitah, Ela Anjarwati, Darmawan Darmawan http://creativecommons.org/licenses/by-nc-nd/4.0
PHYSICO-MECHANICAL PROPERTIES OF THAILAND AND YELLOW BAMBOO PLANTED IN LAGUNA AND BENGUET, PHILIPPINES
ARTICLE HIGLIGHTS - Thailand bamboo showed higher density and strength for structural use - Yellow bamboo suited for composites, crafts, and fiber boards - Species, site, and culm height influence bamboo performance ABSTRACT Bamboo is gaining recognition as a sustainable construction material, but data on the physico-mechanical properties of species grown in the Philippines remain limited. This study assessed Thailand bamboo (Thyrsostachys siamensis Gamble) and yellow bamboo (Bambusa vulgaris Schrad. ex J.C. Wendl.) planted in Laguna and Benguet. Tests were conducted following ASTM D143 (2019) and ISO 22157 (2019) standards, focusing on moisture content (MC), basic relative density (RD), shrinkage, static bending, compression (CPG), and shear strength parallel to the grain (SS). Significant interspecies differences were observed. Yellow bamboo exhibited higher MC (34%), radial (32%), tangential (92%), and volumetric shrinkage (53%), while Thailand bamboo had 29% higher RD, indicating better mechanical performance. Location influenced several properties, i.e., yellow bamboo from Laguna showed 46% higher MC, while Benguet samples showed higher modulus of elasticity and stress at the proportional limit. Thailand bamboo from Laguna had a 7% higher modulus of rupture, while yellow bamboo from Benguet showed 42% increase compared to Laguna. Thailand bamboo from Benguet showed higher CPG and SS, though yellow bamboo from Laguna outperformed in these properties. Axial position affected MC, shrinkage, CPG, and SS, but node presence did not influence CPG and SS. The higher density and strength of Thailand bamboo make it ideal for structural applications, whereas the larger culm and softer fibers of yellow bamboo are ideal for handicrafts, composites boards, and bioenergy.
Copyright (c) 2026 Oliver S. Marasigan, Mario Angelo M. Mundin, Shereyl A. Daguinod, Jayric F. Villareal http://creativecommons.org/licenses/by-nc-nd/4.0
TREE CARBON STOCK ESTIMATION AND MODELING OF PALSABANGON WATERSHED USING THE INVEST MODEL IN QUEZON PROVINCE, PHILIPPINES
ARTICLE HIGLIGHTS - First carbon mapping of Palsabangon watershed using InVEST model - Combines remote sensing and field data across four key vegetation types - Reveals mangroves store highest carbon per hectare among land covers - Secondary forests hold largest total carbon due to broader area coverage - Informs creation of carbon conservation zones in vulnerable watershed areas ABSTRACT The Palsabangon Watershed is primarily composed of young secondary forests, shrublands, agroforestry, and remnant mangrove stands that are increasingly threatened by land-use conversion, resource extraction, and natural disturbances. The watershed remains undeclared and unprotected by law in the southern Sierra Madre Mountain Range of Quezon Province, Philippines. Despite these pressures, the watershed continues to play an important role in carbon sequestration and climate regulation. To assess carbon stock, four vegetation types; secondary forest, shrubland, agroforestry, and mangrove were evaluated through quadrat sampling using thirteen 5 m × 40 m rectangular plots. Tree carbon was estimated using allometric equations, and land use/land cover maps were generated from Sentinel-2 satellite imagery. The dominant vegetation cover was secondary forest, followed by shrubland, agroforestry, and mangrove forest. Carbon stock estimation was performed using the Carbon Storage and Sequestration model within the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) software. The estimates of tree carbon stock (C) in Palsabangon Watershed revealed that mangrove forests had the highest density (85.1 MgC/ha), followed by secondary forests (67.8 MgC/ha), agroforestry (50.4 MgC/ha), and shrublands (43.3 MgC/ha). Tree carbon stock in mangroves and secondary forests was attributed to the younger age and declining tree density of these ecosystems, caused by anthropogenic and natural factors. The total tree carbon stock of the watershed was estimated at 295,674 tonnes C, with secondary forests contributing the most (140,666.7 tonnes C). Despite the young age of the forest stands, the watershed demonstrates significant potential for carbon accumulation. To ensure long-term sustainability, we recommend the establishment of forest carbon conservation zones to protect and enhance carbon sequestration capacity of the watershed.
Copyright (c) 2026 Raffy D. Gordula, Nelson M. Pampolina, Cristino L. Tiburan Jr., Inocencio E. Buot Jr. http://creativecommons.org/licenses/by-nc-nd/4.0
ECOLOGICAL ASSESSMENT OF SETU RIVER POLLUTION USING SAPROBIC INDEX AND AQUATIC BIOTA DIVERSITY
ARTICLE HIGLIGHTS - Combined saprobic index and plankton diversity assess Setu River pollution - Untreated batik wastewater affects river water quality and biodiversity - Eutrophic tolerant diatoms dominate polluted river sections - Benthic communities reflect persistent ecological disturbance ABSTRACT The batik industry in Indonesia, especially in Pekalongan, has seen rapid growth since being recognized by UNESCO. However, this growth has brought increasing environmental concerns, particularly related to wastewater discharge from small-and medium-scale enterprises. This study assessed the ecological condition of the Setu River in South Pekalongan by integrating plankton diversity metrics and the saprobic index (SI) to evaluate the impact of batik effluents. Sampling was carried out in November 2024 at three representative locations selected to reflect different pollution gradients along the Setu River: upstream, the Jenggot Waste Water Treament Plant (WWTP) outfall, and downstream. Water quality showed a declining trend along the river, reflecting increasing anthropogenic pressures. Phytoplankton abundance ranged from 561 to 1,190 individuals/L, with dominant genera such as Navicula, Synedra, and Nitzschia, which are known indicators of organic pollution. Zooplankton was only observed at the downstream station, with a low diversity index (H’ = 0.6931), suggesting that water conditions were unfavorable for sensitive species. The saprobic index increased from 0.31 upstream to 0.93 downstream, indicating a light level of organic pollution. These findings indicate that the Jenggot communal WWTP may not be operating optimally, as reflected by the high concentrations of pollutant indicators near the outfall. Inadequate wastewater treatment exerts ongoing pressure on aquatic life, reducing biodiversity and disturbing ecological stability. This study emphasizes the urgency of improving wastewater management, particularly through the development of appropriate and low-cost technologies to support small-scale batik industries. Furthermore, plankton-based bioindicators offer a reliable, cost-effective method for monitoring ecological impacts in urban rivers subjected to industrial discharges.
Copyright (c) 2026 Kamtiyah Ningsih, Fuad Muhammad, Aris Mukimin http://creativecommons.org/licenses/by-nc-nd/4.0
UNCOVERING GENETIC PATTERNS OF THE BARRED MUDSKIPPER ALONG THE WEST COAST OF BENGKULU USING THE COI GENE
ARTICLE HIGLIGHTS - First genetic baseline for mudskipper in western Sumatra - One shared lineage links Bengkulu to southern Java - High connectivity along an open, shallow coastline - Coastal tides and currents shape genetic patterns - Findings support regional scale conservation planning ABSTRACT The barred mudskipper, Periophthalmus argentilineatus, is an amphibious gobiid fish that exhibits fully terrestrial behavior during low tides. Previous research has suggested the presence of cryptic species within this taxon, complicating species identification due to highly similar morphological traits. Despite its ecological importance in intertidal ecosystems, information on the genetic variation and population structure of P. argentilineatus in Sumatra remains limited, and no such data have been reported from the West Coast of Bengkulu. Therefore, this study aimed to assess the genetic diversity and population structure of P. argentilineatus along this coastline using the mitochondrial COI gene. A total of 30 individuals were collected from three locations, i.e., Air Hitam Coast, Baai Mangrove Forest, and Teluk Sepang Coast. The COI gene was amplified (approximately 660 bp), and a final aligned fragment of 630 bp was used for genetic analyses. Phylogenetic reconstruction placed all Bengkulu samples within a single lineage corresponding to Clade C previously reported from southern Java. Clades A and B were not detected in the study area. Genetic distances among individuals ranged from 0.00 – 0.80%, indicating close relatedness within this lineage. Sequence analysis identified nine variable sites, including two parsimony-informative positions, resulting in nine haplotypes. Haplotype diversity was moderate (Hd = 0.708), whereas nucleotide diversity was low (π = 0.00182). Negative Tajima’s D values suggest recent demographic expansion or ongoing connectivity among populations. AMOVA and Fst analyses indicated low or undetectable genetic differentiation among sampling sites, consistent with substantial gene flow along the coastline. These findings establish a baseline genetic reference for P. argentilineatus in Bengkulu and contribute to understanding regional population connectivity along the western Indonesian coastline.
Copyright (c) 2026 Fanni Khoirillah, Zuliyati Rohmah, Rury Eprilurahman, Tuty Arisuryanti http://creativecommons.org/licenses/by-nc-nd/4.0
SPECIES DIVERSITY AND CARBON STOCK OF DECIDUOUS DIPTEROCARP FOREST UNDER THAILAND COMMUNITY FOREST MANAGEMENT
ARTICLE HIGHLIGHTS - Although Ban Yod Udom Community Forest is classified as a secondary dipterocarp forest, it shows considerable diversity in woody species. - Ban Yod Udom Community Forest is dominated by several economically important tree species found in Southeast Asia and Thailand, including Sindora siamensis, Xylia kerrii, and Pterocarpus macrocarpus, as evidenced by their high density, frequency, and basal area values. - The biomass and carbon stock in Ban Yod Udom Community Forest is lower than that of other deciduous dipterocarp forests in the same region; however, species richness and density are comparatively higher. ABSTRACT Sustainable and efficient forest management is widely recognized as an effective strategy for reducing greenhouse gas emissions, which are a primary driver of global warming. This study investigated woody species composition and diversity, and estimates carbon stocks in the deciduous dipterocarp forest managed under the community forestry scheme at Ban Yod Udom Community Forest, Sa Kaeo Province, Eastern Thailand. A total of 55 sampling plots were systematically established at 100 m intervals throughout the community forest area. Each plot measured 20 m × 20 m for tree assessment, 4 m × 4 m for saplings, and 1 m × 1 m for seedlings. Species composition and diversity were assessed using density, frequency, dominance, and diversity indices, as well as importance value index (IVI). Biomass was estimated using allometric equations, while carbon stock and carbon absorption were calculated accordingly. A total of 55 species from 26 families were identified, with the Fabaceae family exhibiting the highest species richness, with 9 species. Tree, sapling, and seedling densities were 1,014.09; 4,931.81; and 38,602.94 stems/ha, respectively. Sindora siamensis, Memecylon scutellatum, Xylia kerrii, Pterocarpus macrocarpus, and Lannea coromandelica were identified as ecologically significant trees based on the highest IVI. M. scutellatum was the most dominant sapling, while S. siamensis was the most prevalent among seedlings. The Shannon–Wiener index ranged from 1.31 to 2.16, indicating low diversity. Dominant woody species at various growth stages contributed greater biomass, carbon stocks, and carbon absorption than other species. The total tree biomass in the community forest was 52.26 tonnes/ha, corresponding to a total carbon stock of 24.56 tonnes C/ha and a total carbon absorption of 90.06 tonnes CO2/ha. Saplings contributed a total biomass of 2.98 tonnes/ha, a total carbon stock of 1.40 tonnes C/ha, and a total carbon absorption of 5.13 tonnes CO2/ha. To enhance species diversity and carbon storage in this community forest, it is recommended to increase enrichment planting and implement protective measures, such as wildfire management and regulation of non-timber forest products (NTFP) utilization.
Copyright (c) 2026 Boontida Moungsrimuangdee, Yodsaphon Phuengchiam, Nutchanat Plodkrathok, Prapatsorn Yodsa-Nga, Panya Waiboonya http://creativecommons.org/licenses/by-nc-nd/4.0
EFFECT OF DIFFERENT CULTURE MEDIA ON THE GROWTH AND CHLOROPHYLL-a CONTENT OF Navicula sp. and Synechococcus sp
ARTICLE HIGLIGHTS - Walne medium significantly enhances microalgae growth and chlorophyll-a content. - F2+Si medium effectively supports Navicula sp. growth in cultivation. - Urea+NPK limits microalgae due to nutrient deficiency. - Optimal media selection is crucial for tropical microalgae cultivation. ABSTRACT This research addressed a critical knowledge gap regarding the optimal cultivation conditions for indigenous microalgal strains from high-biodiversity tropical marine ecosystems, offering insights into their physiological responses to varied nutrient regimes. In particular, this study focused on evaluating the effect of three different culture media (Walne, F2+Si, and Urea+NPK) on the growth and chlorophyll-a content of local microalgae isolates, Navicula sp. and Synechococcus sp., isolated from Southeast Sulawesi waters. The isolates were cultivated at a laboratory scale in January 2025 using 250 mL Erlenmeyer flasks containing 100 mL of media, under continuous aeration at room temperature (26 - 30 °C) and constant illumination (90 µmol photons/m²/s). Growth was monitored every two days. The results demonstrated that Walne medium yielded the highest cell density and chlorophyll-a content for both species. In Walne medium, Navicula sp. reached a peak density of 8,656,000 ± 53,777 cells/mL with a specific growth rate (SGR) of 1.1453 ± 0.033, while the density of Synechococcus sp. reached 4,965,833 ± 16,646 cells/mL with an SGR of 0.8297 ± 0.032. The F2+Si medium also supported good growth, particularly for Navicula sp. (SGR of 1.0967 ± 0.003). However, the Urea+NPK medium consistently produced the lowest results for all parameters due to limitations in micronutrient and vitamin. One-Way ANOVA revealed no significant difference (P > 0.05) between Walne and F2+Si media for the growth of Navicula sp., but Walne medium was significantly superior for Synechococcus sp. This study concluded that the choice of the culture medium is crucial for optimizing microalgal growth. Walne medium is recommended as the optimal medium for cultivating both Navicula sp. and Synechococcus sp., whereas F2+Si serves as an effective alternative for Navicula sp. The findings underscore the importance of comprehensive nutrient formulations for maximizing biomass yield in local isolates and provide a foundation for developing cost-effective cultivation strategies in tropical regions.
Copyright (c) 2026 Haslianti, Wa Ode Nilda Arifiana Effendy, Suwarjoyowirayatno, La Ode Baytul Abidin, Muhaimin Hamzah, Asmariani, Fatmawati, Wa Ode Intiyani Mangurana, Herlan Hidayat, Asjun http://creativecommons.org/licenses/by-nc-nd/4.0