Sex: Male
Education:
- Doctor of Philosophy in Oceanography (Microbial Oceanography), Universite Laval
- Master of Science in Marine Science (Marine Biotechnology), University of the Philippines Diliman
- Bachelor of Science in Biology (Marine Microbial Ecology), University of the Philippines Baguio
Field of Specialization
Microbial Ecology
Environmental Microbiology
Microbial Diversity
Phytoplankton Ecology
Metagenomics
Community Structure
Applied Microbiology
Researches:
Article title: Diversity of Marine Eukaryotic Picophytoplankton Communities with Emphasis on Mamiellophyceae in Northwestern Philippines
Authors: Laurice Beatrice Raphaelle O. dela Peña, Aubrey Joy P. Tejada, John Bennedick Quijano2, Kim Henri Alonzo
Publication title: Philippine Journal of Science 150(1):27-42, February 2021
Abstract:
Eukaryotic picophytoplankton (EPP) play vital roles in primary productivity and biogeochemical cycling in the marine environment. In this study, we explored the diversity of EPP communities in two different embayments and the shifts in their community structuring during monsoonal reversal in the northwestern Philippines. Water samples were collected weekly from late northeast (NE) monsoon to intermonsoon (IM) or summer periods (February-April 2019) in Bolinao, Pangasinan, and once in January in Masinloc, Zambales. EPP community profiling was done through targeted sequencing of the V4 region of the 18S rRNA gene. Grouping of samples based on physicochemical parameters was consistent with that of community beta diversity, suggesting strong clustering between late NE and IM periods. This exhibits short-term community shifts of EPPs possibly associated with the monsoonal transition. Specifically, overall EPP alpha diversity increased towards summer coupled with increased temperature and lower nutrient concentrations. NE monsoon samples from Bolinao and Masinloc were dominated by Chlorophyta and Stramenopiles, while Prymnesiophyta, Rhizaria, and Picozoa dominated the IM period samples in Bolinao. Specifically, the prasinophytes (Chlorophyta) Ostreococcus and Nannochloris distinguished the late NE communities of Masinloc and Bolinao, respectively. Phylogenetic analysis of dominant photosynthetic EPP further revealed the presence of Clades B5 and A1 of Micromonas, as well as Clades B and E of Ostreococcus. Tree topology of Ostreococcus diversity suggests the presence of a clade distinct from other established clades, possibly indicating novel diversity in the West Philippine Sea. This is the first report of these major picophytoplankton in Philippine waters, suggesting their significance and potential "hidden" diversity, which warrants further studies.
Article title: Spatio-temporal variability and association of diatom-dinoflagellate assemblages of Acanthophora, Hypnea and Gracilaria (Rhodophyta)
Authors: Romella T. Beringuela, Daniel John E. Purganan, Rhodora V. Azanza & DeoFlorence L. Onda
Publication title: European Journal of Phycology 55(3):1-11, May 2020
Abstract:
Epiphytic microalgae can significantly affect the host seaweed either by complementing, or competing for, resources. Here, epiphytic diatom and dinoflagellate species assemblages on the macroalgae Acanthophora spicifera, Hypnea pannosa and Gracilaria salicornia collected during the north-east (February), inter- (April) and south-west (June) monsoons in 2015 along the coast of Lucero, Pangasinan, North-western Philippines were examined and characterized. Results showed that diatom–dinoflagellate assemblages strongly clustered by season rather than by geographic location. Within season, a minor clustering by macroalgal forms, rather than host species identity, was also observed, which could be associated with the differences in the complexity and texture of the upright and prostrate seaweeds. Examination of the ‘thallisphere’ using confocal laser scanning microscopy further revealed the close proximity of some of the ‘resident’ epiphytic species to the cortical cells of the host, causing deformities and implying more complex interactions. Our results suggest that epiphytic community assemblages were influenced by both the environmental conditions associated with seasonal variation and the microhabitats in the surface of the different algal forms.
Article title: Marine Microbes and Plastic Debris: Research Status and Opportunities in the Philippines
Authors: Deo Florence L. Onda, Norchel Corcia F. Gomez, Daniel John E. Purganan, Mark Paulo S. Tolentino, et al.
Publication title: Philippine Journal of Science 149(1):89-100, March 2020
Abstract:
Marine plastics have been shown to affect all organisms across the trophic levels including the microbial communities, influencing their community assembly, composition, metabolic processes, and ecosystem functions. Thus, studying plastic-microbe interactions in the marine environment is important in understanding its implications alongside the growing issue of plastic pollution. The Philippines, despite being suggested as the third-largest contributor to marine plastic debris, currently does not have any existing national research programs on basic plastics research, resulting in our limited understanding of the extent and implications in the country. This paper then reviews the current status and knowledge of the plastic-microbe association focusing on how plastic surfaces serve as a new environment for marine microbes, how this system could become dispersal mechanisms of unwanted microorganisms, and how microbes possibly contribute to the biodegradation of plastics in the marine environment. These also translate to possible research opportunities for Filipino scientists to work on the topic.
Article title: Algicidal potential of cultivable bacteria from pelagic waters against the toxic dinoflagellate Pyrodinium bahamense (Dinophyceae)
Authors: Jenelle Clarisse R. Dungca-Santos, Frenchly Joyce O. Caspe, Francis A. Tablizo, Daniel John E. Purganan
Publication title: Journal of Applied Phycology 31(6), December 2019
Abstract:
Associated and algicidal bacteria play roles in the succession and decline of phytoplankton blooms, including those of harmful algal bloom (HAB)-forming species. Limited studies on HAB-associated bacterial ecology have resulted in our incomplete understanding of HABs dynamics. Diverse phytoplankton-bacterial interactions have also led to studies on their potential as biocontrol tools for HABs mitigation. Here, we tested 48 cultivable pelagic bacteria from three HAB-affected areas in the Philippines (Bolinao, Sorsogon, and Matarinao) against non-axenic cultures of the toxic, thecate dinoflagellate Pyrodinium bahamense. Co-incubation with live cultures of these isolates exhibited varying levels of algicidal activities suggesting that it may not be a phylogenetically conserved property. Furthermore, majority of the isolates elicited activity against the thecate test species P. bahamense, which was not present in the area where the bacteria were isolated, implying non-specificity of action. Exposure to bacterial cells resulted in Pyrodinium pellicle cyst formation. Despite this, however, cell lysis and decline in total cell abundance were still observed, indicating strong algicidal potency of the isolates. In depth understanding of the interplay between environmental factors and algicidal bacteria-microalgal interactions may provide significant insights on the management of HABs.
Full text available upon request to the author
Article title: Microbial oceanography studies in the context of climate change in the Philippines
Authors: Deo Florence L. Onda, Mary Ann G. Santos, Donna de la Cruz- Papa, Aletta T. Yñiguez
Publication title: Philippine Science Letters 12(1), 2019
Abstract:
Studying ocean microbiomes is important in understanding the effects of the changing environment on our seas. The Philippines, being an archipelago, has been regarded as one of the most vulnerable regions under climate change scenarios, and understanding of the functions and diversity of microbial communities is a paramount step toward mitigating and adapting to the impact of globally or locally catastrophic environmental changes. We explore the current state, challenges, and potentials for microbial oceanography or marine microbial studies in the Philippines, particularly in the context of climate change, and suggest measures on how we can best move forward to upgrade and contribute to the development of this field in the country. Despite the great diversity in the marine provinces in the country and the answers they hold in unlocking the secrets of microbial communities, this review highlights that Philippine-based microbial or marine research in general has been limited. Previous microbial studies focused on applications in aquaculture and fisheries, while more basic aspects such as on diversity and ecological interactions and functioning are sorely lacking. Limited recognition and support for basic research, lack of expertise, and insufficient infrastructure (e.g., properly equipped oceangoing research vessels) were identified as critical bottlenecks in the progress of ocean research in general. The heightened national interest in the country’s oceans and greater awareness of climate change threats can be a means further to spur Philippine oceanographic research that can be strengthened through the mobilization of research networks around the country.
Article title: Summer phytoplankton community structure and distribution in a mariculture-affected coastal environment
Authors: Ritzelle L. Albelda, Daniel John E. Purganan, Norchel Corcia F. Gomez, Bienson Ceasar de Vera Narvarte, et al.
Publication title: Philippine Science Letters 12(2), 2019
Abstract:
Many aspects of the ecological responses of phytoplankton communities toward environmental changes remain little understood. Here, the study investigated correlations of micro-phytoplankton communities across environmental gradients associated with mariculture activities during early (April) and late summer (May). Plankton and physico-chemical profiling of the upper surface waters were carried out in 16 stations from mariculture-affected areas inside the Guiguiwanen channel in Bolinao to non-mariculture areas outside the channel. Community beta-diversity clustered the phytoplankton based on the environments where they were collected, with most communities correlating with high temperature and nutrients (phosphate). Phosphate loading in the area resulted in low total inorganic nitrogen and phosphorus ratio coupled with a shift from a diatom-dominated community (84.8%; non-mariculture areas) to a harmful dinoflagellate dominated community (41.5%; mariculture-affected areas). In addition, zooplankton were generally negatively correlated with phytoplankton, which could indicate grazing. Increase in heavy rainfall towards late summer (late May) was accompanied by increase in nutrients followed by a bloom of putative dinoflagellate Takayama spp. (99%), which coincided with a fish kill event inside the channel. This study shows that continuous intensive aquaculture activities could influence phytoplankton community structures, and in some cases, favor harmful algal bloom-forming species, thereby affecting ecosystem functioning
Article title: Need for focus on microbial species following ice melt and changing freshwater regimes in a Janus Arctic Gateway
Authors: Nathalie Joli, Michel Gosselin, Mathieu Ardyna, Marcel Babin, Deo Florence Onda, et al.
Publication title: Scientific Reports 8(1), June 2018
Abstract:
Oceanic gateways are sensitive to climate driven processes. By connecting oceans, they have a global influence on marine biological production and biogeochemical cycles. The furthest north of these gateways is Nares Strait at the top of the North Water between Greenland and Ellesmere Island (Canada). This gateway is globally beneficial, first by supporting high local mammal and bird populations and second with the outflow of phosphate-rich Arctic waters fueling the North Atlantic spring bloom. Both sides of the North Water are hydrologically distinct with counter currents that make this Arctic portal a Janus gateway, after Janus, the Roman god of duality. We examined oceanographic properties and differences in phytoplankton and other protist communities from the eastern and western sides of the North Water (latitude 76.5°N) and found that species differed markedly due to salinity stratification regimes and local hydrography. Typical Arctic communities were associated with south flowing currents along the Canadian side, while potentially noxious Pseudo-nitzschia spp. were dominant on the Greenland side and associated with greater surface freshening from ice melt. This susceptibility of the Greenland side to Pseudo-nitzschia spp. blooms suggest that monitoring species responses to climate mediated changes is needed.
Article title: Seasonal and Interannual Changes in Ciliate and Dinoflagellate Species Assemblages in the Arctic Ocean (Amundsen Gulf, Beaufort Sea, Canada)
Authors: Deo F. L. Onda, Emmanuelle Medrinal, André M. Comeau, Mary Thaler, et al.
Publication title: Frontiers in Marine Science 4:16, January 2017
Abstract:
Recent studies have focused on how climate change could drive changes in phytoplankton communities in the Arctic. In contrast, ciliates and dinoflagellates that can contribute substantially to the mortality of phytoplankton have received less attention. Some dinoflagellate and ciliate species can also contribute to net photosynthesis, which suggests that species composition could reflect food web complexity. To identify potential seasonal and annual species occurrence patterns and to link species with environmental conditions, we first examined the seasonal pattern of microzooplankton and then performed an in-depth analysis of interannual species variability. We used high-throughput amplicon sequencing to identify ciliates and dinoflagellates to the lowest taxonomic level using a curated Arctic 18S rRNA gene database. DNA-and RNA-derived reads were generated from samples collected from the Canadian Arctic from November 2007 to July 2008. The proportion of ciliate reads increased in the surface toward summer, when salinity was lower and smaller phytoplankton prey were abundant, while chloroplastidic dinoflagellate species increased at the subsurface chlorophyll maxima (SCM), where inorganic nutrient concentrations were higher. Comparing communities collected in summer and fall from 2003 to 2010, we found that microzooplankton community composition change was associated with the record ice minimum in the summer of 2007. Specifically, reads from smaller predatory species like Laboea, Monodinium, and Strombidium and several unclassified ciliates increased in the summer after 2007, while the other usually summer-dominant dinoflagellate taxa decreased. The ability to exploit smaller prey, which are predicted to dominate the future Arctic, could be an advantage for these smaller ciliates in the wake of the changing climate
Article title: Potential DMSP-degrading Roseobacter clade dominates endosymbiotic microflora of Pyrodinium bahamense var. compressum (Dinophyceae) in vitro
Authors: Deo Florence L. Onda, Rhodora V. Azanza, Arturo O. Lluisma
Publication title: Archives of Microbiology 197(7):1-7, July 2015
Abstract:
Many aspects of the biology and ecology of the toxic dinoflagellate Pyrodinium bahamense var. compressum are still poorly understood. In this brief note, we present identification of its associated intracellular bacteria or endosymbionts via PCR cloning and 16s rRNA gene sequencing and their localization by confocal microscopy, a first for Pyrodinium. The most frequently observed species in the endosymbiotic microflora were from Roseobacter clade (Alphaproteobacteria, 68 %) and Gilvibacter sediminis (Flavobacteriaceae, 20 %). Roseobacter lineage, the most abundant taxa in this study, is known to be involved in dimethylsulfoniopropionate metabolism which is highly produced in dinoflagellates—a possible strong factor shaping the structure of the associated bacterial community.
Article title: Dominance of Hydrogenotrophic Methanogens at the Peak of Biogas Production in Thalassic Digesters
Authors: Gian Powell B. Marquez, Wolfgang T. Reichardt, Rhodora V. Azanza, Deo Florence L. Onda, et al.
Publication title: Waste and Biomass Valorization 6:201-207, April 2015
Abstract:
Marine biomasses used in biogasification system are usually treated as terrestrial feedstock after salt removal. However, biogas production of sea wrack biomass run under thalassic (marine) conditions, and seeded with different inocula [cow manure (CM), marine sediment (MS) and sea wrack-associated (SWA) microflora] showed the potential for cheaper alternative to freshwater utilization (terrestrial conditions). To understand how methane yield is affected by the different inoculants under thalassic conditions, methanogenic communities in these digesters (CM, MS, SWA) were quantified using double-labeled oligonucleotide probes to a modified fluorescence in situ hybridization at the peak of biogas production. Total targeted methanogens were highest in SWA (1.51 ± 0.53 × 107 cells ml−1) while lowest in CM (1.79 ± 0.20 × 106 cells ml−1). Among all types of targeted methanogens, hydrogenotrophs (Methanobacteriales and Methanomicrobiales) dominated in all digesters (CM 73.2 ± 7 %, MS 58.4 ± 8.0 %, SWA 61.2 ± 5.4 %). Moreover, MS showed mixotrophic Methanosarcinaceae (30.2 ± 8.1 %) co-dominance, suggesting that their population could have influenced the higher methane yield in MS.
Full text available upon request to the author
Article title: Development, morphological characteristics and viability of temporary cysts of Pyrodinium bahamense var. compressum (Dinophyceae) in vitro
Authors: Deo Florence L. Onda, Arturo O. Lluisma & Rhodora V. Azanza
Publication title: European Journal of Phycology 49(3), July 2014
Abstract:
Pellicle or temporary cysts of Pyrodinium bahamense var. compressum (Böhm) Steidinger, Tester & F.J.R. Taylor and their role in bloom dynamics have not yet been adequately characterized and understood. We investigated the role of temperature- and nutrient-mediated stress as factors that could induce pellicle formation in batch cultures. Cellular features and their implications for temporary cyst viability were examined using confocal laser scanning microscopy (CLSM). Our data suggest that temperature change is one of the key factors influencing pellicle formation, preserving viability at low temperature (i.e. 13°C). Hypnocysts (resting cysts) were not observed. During pellicle formation, motile cells generally undergo ecdysis, extrusion of cytoplasmic materials and bacteria, compaction of the nucleus and non-motility. The outermost covering of the temporary cysts shows red autofluorescence and it contains lower concentrations of chlorophyll (chl) a and no detectable chl c. The nuclear region is surrounded by transitional red bodies and other unidentified cellular structures. Temporary cysts can immediately revert back to the motile state upon exposure to optimum conditions. This is accompanied by the expansion of the nuclear region, regeneration of the chloroplasts and enlargement of the cell. Developmental changes during reversal of temporary cysts to motile forms were also observed to cause breaks in the cell covering that could serve as sites for bacterial entry. Though observed in vitro, such behaviour may also be occurring in nature especially as a response to drastic short-lived environmental changes. This is the first detailed report on the characteristics of temporary cysts of P. bahamense var. compressum.
Article title: Culturable algalytic bacteria isolated from seaweeds in the Philippines and Japan
Authors: Rhodora V. Azanza, Vanessa, Mercee D. Vargas, Kimio Fukami, Keshavmurthy Shashank, et al.
Publication title: Journal of Environmental Science and Management 1:1-10, August 2013
Abstract:
Bacteria from seaweeds as epibionts have been reported to have major role/s in algal physiology and survival by secreting compounds with bioactivity like inhibitory/other potential harmful/pathogenic effects. Some of these epibionts have been reported to cause mortality against certain species of noxious phytoplankton, i.e. fish-killing and toxic species. In this study, we report a total of 13 algalytic bacteria isolated and genetically identified from surfaces of seaweeds from Japan and the Philippines, mostly belonging to phylum proteobacteria. The effects on the motility and viability of Alexandrium catenella (Whedon and Kofoid) Balech, Chattonella antiqua (Hada) Ono, Skeletonema costatum (Grev.) Cleve, and Symbiodinium sp. were observed for 48 hours. From Japan, Vibrio sp. from Gracilaria sp. and Ulva sp. were most potent. Pseudoalteromonas sp. from a farmed Kappaphycus alvarezii (Doty) Doty in the Philippines was the fastest killing eliciting 100 % mortality on Pyrodinium bahamense var. compressum (Bohm) Steidinger, Tester and Taylor, during the first 24 h of incubation. Results suggest that athecate species are less resilient than the thecate dinoflagellates. Alterierythrobacter sp. and Ruegeria sp. belonging to subphylum α-proteobacteria that have not yet been previously reported to exhibit algalytic activity were also studied.
Article title: Morphological and molecular characterization of some HAB-forming dinoflagellates from Philippine waters
Authors: Deo Florence L. Onda, Garry Benico, Arielle F. Sulit, Paul Lorenzo Gaite
Publication title: Philippine Science Letters 6(1), 2013
Abstract:
Various species of toxic dinoflagellates have been isolated from various sites in the Philippines. In this study, we characterized a number of these isolates using a molecular approach and Confocal Laser Scanning Microscopy (CLSM). Phylogenetic analysis using genetic markers (LSU rDNA, SSU rDNA, and cytochrome oxidase b) confirmed the identity of the isolates as Pyrodinium bahamense var. compressum, Alexandrium affine, Gymnodinium catenatum, Prorocentrum sigmoides, P. micans and P. rhathymum. Morphological differences among strains of Pyrodinium were very minor and could not be readily correlated with geographical variation. Intra-species polymorphism in the form of single nucleotide polymorphisms (SNPs) and deletions/insertions in the sequences were also observed. However, in general, the SNPs in these V markers are too few and may not provide sufficient resolution to allow these markers to be used for population genetic studies.
Article title: Algicidal Bacteria from fish culture areas in Bolinao, Pangasinan, Northern Philippines
Authors: Kamille Joshua V. Manset, Rhodora V. Azanza, Deo Florence L. Onda
Publication title: Journal of Environmental Science and Management 16, January 2013
Abstract:
The first record of bacteria with algicidal activity against Alexandrium sp. strain AMBRVA031710, a Harmful Algal Bloom (HAB)-causing dinoflagellate was isolated from Bolinao, Pangasinan. Water samples for bacterial isolation were collected from 14 selected stations in Bolinao during the Northeast (NE) Monsoon, Tradewind (TW) and Southwest (SW) Monsoon in 2010-2011. One hundred ten (110) bacteria were screened, thirty (30) showed algicidal activity against Alexandrium sp. and 13 genetically identified bacteria caused loss of motility to AMBRVA03171 after the first hour of interaction. These were Vibrio sp., V. parahaemolyticus, Pseudomonas sp., Pseudomonas aeruginosa, Pseudomonas viridis, Pseudoalteromonas sp., Ruegeria lacuscaerulensis, Halobacillus sp., and Algoriphagus sp., and two isolates of V. harveyi and uncultured bacterium. These bacteria were tested against five other HAB-causing dinoflagellates isolated from the Philippines, namely Pyrodinium bahamense strain PbcMZRVA042595; Alexandrium affine strain AAFHBRVA102905; Amphidium carterae strain ACARABRVABML; Gymnodinium catenatum strain GcMBRVA011810 and Ostreopsis ovata strain OOVBOLMBRVA111510. After 24 h of incubation, the five dinoflagellate species showed more lysis but those in the control wells remained motile and unaffected. Isolated algicidal bacteria can be used to improve management of these HABs and can also be utilized for applied studies on their active substances.