National Committee on Marine Sciences (NCMS)
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- Quantifying vertical land motion at tide gauge sites using permanent scatterer interferometric synthetic aperture radar and global navigation satellite system solutionsReyes, Rosalie; Bauzon, Ma. Divina Angela; Pasaje, Nikki Alen; Alfante, Rey Mark; De Lara, Pocholo Miguel; Ordillano, Marion; Flores, Paul Caesar; Rediang, Abegail; Nota, Patrick Anthony; Siringan, Fernando; Blanco, Ariel; Bringas, Dennis (Springer, 2022-01-29)One of the consequences of climate change is sea level rise (SLR). Near the coast SLR varies at different locations due to the contributions from regional/local climatic and non-climatic factors. Vertical land motion (VLM) can affect the accuracy of sea level observations from tide gauges (TG) that may exacerbate coastal area inundation/flooding. This study investigated the viability of Permanent Scatterer Interferometric Synthetic Aperture Radar (PSInSAR) to quantify the rate of VLM at the TG sites. Measurements from TG co-located GNSS receivers provide the actual VLM rates and ground truth for PSInSAR-derived rates. Based on the results from the 9 study sites, almost all except one are subsiding. Both PSInSAR and GNSS solutions showed the same trend with rates that correlate at 0.89. Analysis from 20 Active GNSS stations showed 95% of the sites are undergoing land subsidence. This should be a cause of concern for communities near the coastal areas.
- Bacterial community assembly, succession, and metabolic function during outdoor cultivation of Microchloropsis salinaMorris, Megan M.; Kimbrel, Jeffrey A.; Geng, Haifeng; Tran-Gyamfi, Mary Bao; Yu, Eizadora T.; Sale, Kenneth L.; Lane, Todd W.; Mayali, Xavier (American Society for Microbiology, 2022-08-31)
Outdoor cultivation of microalgae has promising potential for renewable bioenergy, but there is a knowledge gap on the structure and function of the algal microbiome that coinhabits these ecosystems. Here, we describe the assembly mechanisms, taxonomic structure, and metabolic potential of bacteria associated with Microchloropsis salina cultivated outdoors. Open mesocosms were inoculated with algal cultures that were either free of bacteria or coincubated with one of two different strains of alga-associated bacteria and were sampled across five time points taken over multiple harvesting rounds of a 40-day experiment. Using quantitative analyses of metagenome-assembled genomes (MAGs), we tracked bacterial community compositional abundance and taxon-specific functional capacity involved in algal-bacterial interactions. One of the inoculated bacteria (Alteromonas sp.) persisted and dispersed across mesocosms, whereas the other inoculated strain (Phaeobacter gallaeciensis) disappeared by day 17 while a taxonomically similar but functionally distinct Phaeobacter strain became established. The inoculated strains were less abundant than 6 numerically dominant newly recruited taxa with functional capacities for mutualistic or saprophytic lifestyles, suggesting a generalist approach to persistence. This includes a highly abundant unclassified Rhodobacteraceae species that fluctuated between 25% and 77% of the total community. Overall, we did not find evidence for priority effects exerted by the distinct inoculum conditions; all mesocosms converged with similar microbial community compositions by the end of the experiment. Instead, we infer that the 15 total populations were retained due to host selection, as they showed high metabolic potential for algal-bacterial interactions such as recycling alga-produced carbon and nitrogen and production of vitamins and secondary metabolites associated with algal growth and senescence, including B vitamins, tropodithietic acid, and roseobacticides.
IMPORTANCE Bacteria proliferate in nutrient-rich aquatic environments, including engineered algal biofuel systems, where they remineralize photosynthates, exchange secondary metabolites with algae, and can influence system output of biomass or oil. Despite this, knowledge on the microbial ecology of algal cultivation systems is lacking, and the subject is worthy of investigation. Here, we used metagenomics to characterize the metabolic capacities of the predominant bacteria associated with the biofuel-relevant microalga Microchloropsis salina and to predict testable metabolic interactions between algae and manipulated communities of bacteria. We identified a previously undescribed and uncultivated organism that dominated the community. Collectively, the microbial community may interact with the alga in cultivation via exchange of secondary metabolites which could affect algal success, which we demonstrate as a possible outcome from controlled experiments with metabolically analogous isolates. These findings address the scalability of lab-based algal-bacterial interactions through to cultivation systems and more broadly provide a framework for empirical testing of genome-based metabolic predictions.
- MPA-FishMApp – a citizen science app that simplifies monitoring of coral reef fish density and biomass in marine protected areasAbesamis, Rene; Balingit, Rodel; de Castro, Romulo; Aguila, Raphael Nelo; Cabiguin, Maryjune; Villagracia, Julius; Susmeña, Marynoll; Montemar, Mario Neil; Yocor, Antonio (National Fisheries Research and Development Institute, 2022-12)Monitoring changes in fish density and biomass inside marine protected areas (MPAs) through fish visual census (FVC) can determine if MPAs are achieving their goal of promoting fish population recovery. Simplified FVC methods have been developed for citizen scientists to enable them to monitor fish populations in MPAs. However, MPA monitoring programs led by local stakeholders remain rare and difficult to sustain due to technical barriers related to FVC data management. Here, we describe and evaluate a novel online app called MPA-FishMApp, which we developed to help stakeholders of MPAs that protect coral reefs in the Philippines efficiently store, analyze, and visualize FVC data. MPA-FishMApp is coupled to a simplified FVC method wherein the observer records only 21 reef fish species groups during surveys. The app provides a simple data entry interface, cloud storage, and algorithms to estimate fish density and biomass. Spatial and temporal trends in fish density and biomass can be instantaneously visualized in the app based on relative importance to fisheries. Field testing suggested that the MPA-FishMApp methodology (simplified FVC and app) is sensitive enough to detect qualitative patterns showing differences in density and biomass that may develop between MPAs and fished sites, especially in fishes that are highly important to fisheries. However, users must have sufficient training and experience in simplified FVC to produce reliable data. MPA-FishMApp may help reverse the lack of monitoring in MPAs across the Philippines and offers an accessible, transparent, and auditable venue for collaboration between citizen scientists and professional scientists.
- A conserved biosynthetic gene cluster is regulated by quorum sensing in a shipworm symbiontRobes, Jose Miguel D.; Altamia, Marvin A.; Murdock, Ethan G.; Concepcion, Gisela; Haygood, Margo G.; Puri, Aaron W. (American Society for Microbiology, 2022-06-14)Bacterial symbionts often provide critical functions for their hosts. For example, wood-boring bivalves called shipworms rely on cellulolytic endosymbionts for wood digestion. However, how the relationship between shipworms and their bacterial symbionts is formed and maintained remains unknown. Quorum sensing (QS) often plays an important role in regulating symbiotic relationships. We identified and characterized a QS system found in Teredinibacter sp. strain 2052S, a gill isolate of the wood-boring shipworm Bactronophorus cf. thoracites. We determined that 2052S produces the signal N-decanoyl-l-homoserine lactone (C10-HSL) and that this signal controls the activation of a biosynthetic gene cluster colocated in the symbiont genome that is conserved among all symbiotic Teredinibacter isolates. We subsequently identified extracellular metabolites associated with the QS regulon, including ones linked to the conserved biosynthetic gene cluster, using mass spectrometry-based molecular networking. Our results demonstrate that QS plays an important role in regulating secondary metabolism in this shipworm symbiont. This information provides a step toward deciphering the molecular details of the relationship between these symbionts and their hosts. Furthermore, because shipworm symbionts harbor vast yet underexplored biosynthetic potential, understanding how their secondary metabolism is regulated may aid future drug discovery efforts using these organisms.
- Somatostatin venom analogs evolved by fish-hunting cone snails: From prey capture behavior to identifying drug leadsRamiro, Iris Bea L.; Bjørn-Yoshimoto, Walden E.; Imperial, Julita S.; Gajewiak, Joanna; Salcedo, Paula Flórez; Watkins, Maren; Taylor, Dylan; Resager, William; Ueberheide, Beatrix; Bräuner-Osborne, Hans; Whitby, Frank G.; Hill, Christopher P.; Martin, Laurent F.; Patwardhan, Amol; Concepcion, Gisela; Olivera, Baldomero M.; Safavi-Hemami, Helena (American Association for the Advancement of Science, 2022-03-25)Somatostatin (SS) is a peptide hormone with diverse physiological roles. By investigating a deep-water clade of fish-hunting cone snails, we show that predator-prey evolution has generated a diverse set of SS analogs, each optimized to elicit specific systemic physiological effects in prey. The increased metabolic stability, distinct SS receptor activation profiles, and chemical diversity of the venom analogs make them suitable leads for therapeutic application, including pain, cancer, and endocrine disorders. Our findings not only establish the existence of SS-like peptides in animal venoms but also serve as a model for the synergy gained from combining molecular phylogenetics and behavioral observations to optimize the discovery of natural products with biomedical potential.
- Microscopic stages of North Atlantic Laminaria digitata (Phaeophyceae) exhibit trait-dependent thermal adaptation along latitudesSchimpf, Nele M.; Liesner, Daniel; Franke, Kiara; Roleda, Michael Y.; Bartsch, Inka (Frontiers Media SA, 2022-06-17)Kelp forests in the North Atlantic are at risk of decline at their warm temperature distribution margins due to anthropogenic temperature rise and more frequent marine heat waves. To investigate the thermal adaptation of the cold-temperate kelp Laminaria digitata, we sampled six populations, from the Arctic to Brittany (Spitsbergen, Tromsø, Bodø [all Norway], Helgoland [Germany], Roscoff and Quiberon [both France]), across the species’ entire distribution range, spanning 31.5° latitude and 12-13°C difference in mean summer sea surface temperature. We used pooled vegetative gametophytes derived from several sporophytes to approximate the genetic diversity of each location. Gametophytes were exposed to (sub-) lethal high (20-25°C) and (sub-) optimal low (0-15°C) temperature gradients in two full-factorial, common-garden experiments, subjecting subsets of populations from different origins to the same conditions. We assessed survival of gametophytes, their ability to develop microscopic sporophytes, and subsequent growth. We hypothesized that the thermal performance of gametophytes and microscopic sporophytes corresponds to their local long-term thermal history. Integrated gametophyte survival revealed a uniform upper survival temperature (UST) of 24°C among five tested populations (Tromsø to Quiberon). In contrast, following two weeks of thermal priming of gametophytes at 20-22°C, sporophyte formation at 15°C was significantly higher in southern populations (Quiberon and Roscoff) compared to the high-latitude population of Tromsø. Between 0-15°C, survival of the Arctic population (Spitsbergen) was negatively correlated with increasing temperatures, while the southern-most population (Quiberon) showed the opposite. Thus, responses of survival at low, and sporophyte formation at high temperatures, support the concept of local adaption. On the other hand, sporophyte formation between 0-15°C peaked at 6-9°C in the Quiberon and at 9-12°C in the Spitsbergen population. Sporophyte growth rates (GR) both in length and width were similar for Spitsbergen, Tromsø and Quiberon; all had maximum GRs at 12-15°C and low GRs at 0-6°C. Therefore, responses of sporophyte formation and growth at low temperatures do not reflect ecotypic adaptation. We conclude that L. digitata populations display trait-dependent adaptation, partly corresponding to their local temperature histories and partly manifesting uniform or unpredictable responses. This suggests differential selection pressures on the ontogenetic development of kelps such as L. digitata.We would like to thank A. Wagner for the sampling and clonal isolation of kelp material and technical assistance in the laboratory, C. Daniel for support with the image analysis, L. Foqueau for the SST data, C. Gauci for statistical advice and S. DeAmicis for supervision in this BSc Thesis.
- Spatial and short-term temporal patterns of octocoral assemblages in the West Philippine SeaLalas, Jue Alef A.; Lim, Romina Therese S.; Cabasan, Joey P.; Segumalian, Christine S.; Luciano, Rhea Mae A.; Valino, Darryl Anthony M.; Jacinto, Melchor R.; Arceo, Hazel O.; Baria-Rodriguez, Maria Vanessa (Frontiers Media SA, 2022-01-06)Octocorals are relatively understudied than other coral reef organisms despite their ecological and economic values. The Philippines is known to have high marine biodiversity, but information on octocorals is lacking. This study investigated spatial and temporal variations in the assemblage of octocorals in selected reef sites in the West Philippine Sea (WPS)- the Kalayaan Island Group (i.e., Pag-asa, Sabina, Lawak, and Northeast Investigator) and Ulugan in 2017 and 2019. Results showed high octocoral taxonomic richness (at least 10 families) in the study sites. Mean percent octocoral cover in WPS was 5.35% SE ± 0.55, with Sabina having the highest octocoral cover in both years. Significant differences in octocoral cover were observed among sites in both years, but among-station differences were only observed in 2017. Octocoral assemblage also differed among sites in both years (ANOSIM: R > 0.5, p < 0.05), wherein different octocoral taxa dominated in different sites. In particular, variations were driven by high cover of holaxonians, nephtheids, and coelogorgiids in Sabina, and clavulariids, tubiporiids, and xeniids in Northeast Investigator in 2017. In 2019, significant variations were driven by high cover of helioporiids in Pag-asa, while Sabina had higher abundance of holaxonians, nephtheids, alcyoniids, and xeniids. Short-term temporal variation on octocoral cover in monitoring stations in Pag-asa was not observed (Kruskal-Wallis, p > 0.05), although the overall mean octocoral cover increased from 1.23% ± SE 0.47 in 2017 to 2.09% SE ± 0.37 in 2019. Further, there was no significant change in the octocoral assemblage in Pag-asa between years (ANOSIM, R = 0.11, p = 0.07). This study highlights high octocoral taxonomic richness in the WPS relative to other sites in the Indo-Pacific Region and provides baseline information on the octocoral assemblages, which can be useful for future ecological studies and marine biodiversity conservation efforts.We would like to thank the Department of Agriculture-Bureau of Fisheries and Aquatic Resources (DA-BFAR), Philippine Coast Guard (PCG), the Municipality of Kalayaan, and the Philippine Navy for their assistance and support during the research expeditions in the West Philippine Sea. We also thank Lovely Joy Heyres for assisting in the field collection and image analysis, and Kevin Yatco and Socorro Rodrigo for assisting in the satellite product processing. We also thank the valuable insights and suggestions given by the editor and reviewers of this journal that helped improve this manuscript.
- Marine macroalgal reference culture collection at the University of the Philippines Marine Science Institute (UP-MMARCC): Status and prospects for advancing Philippine phycologySantiañez, Wilfred John E.; Guerta, Christian Ace T.; Lastimoso, John Michael L. (Assocation of Systematic Biologists in the Philippines, 2022-11-16)Seaweeds research in the Philippines-from studies on their diversity, natural products chemistry, and the utilization of their derivatives-is largely based on spot collections of large and conspicuous components of the seaweed flora found along the coasts. Such efforts are often focused on commercially important seaweeds; thus, most of the smaller and even microscopic seaweeds remain understudied, if not completely overlooked. Consequently, little to none is known on many aspects of the biology, ecology, and even biochemistry of these components of the Philippine seaweed flora. To understand aspects of seaweed biology and serve as a facility for preserving the genetic resources of Philippine seaweeds, we established the Marine Macroalgal Reference Culture Collection at the University of the Philippines Marine Science Institute (UP-MMARCC). We are currently maintaining 446 seaweed strains (or isolates) collected from several coastal and offshore areas in the Philippines, the latter including the Kalayaan Island Group in the West Philippine Sea, and 25 isolates from Okinawa, Japan. To our knowledge, the UP-MMARCC is the most diverse and widely sampled culture collection in the Philippines so far. Moreover, our preliminary molecular-assisted biodiversity studies suggest that UP-MMARCC houses several isolates that are either new records to the Philippines or putative new taxa. We anticipate that with continued support, we will be able to sustain and expand our culture collection, not only to facilitate discoveries but also to cater to the needs of the Philippine seaweed industry and in support of its call for diversifying our seaweed commodities and their products.
- Nearshore to offshore trends in plankton assemblage and stable isotopes in reefs of the West Philippine SeaYñiguez, Aletta T.; Apego, Gianina Cassandra May; Mendoza, Norman; Gomez, Norchel Corcia; Jacinto, Gil S. (Frontiers Media SA, 2022-01-25)Coral reefs are typified by their benthic components, and reef diversity and productivity are traditionally ascribed to the symbiotic association between corals and zooxanthellae, and other macroalgal forms. Less understood is the role of plankton and adjacent pelagic areas in contributing to reef productivity. Half of the reef benthos are filter or particle feeders, while a significant proportion of reef fishes are planktivorous. These organisms can serve as bridges between adjacent oceanic areas to the reef proper, and the pelagic and benthic realm. Here, we investigate the plankton trophic dynamics in two reef systems in the West Philippine Sea. Physico-chemical data, phytoplankton and mesozooplankton samples were collected from stations spanning offshore to reef areas per site. These were subjected to microscopic and stable isotope analysis to determine variability in plankton distribution, phytoplankton and zooplankton interactions, and gain insights into the trophic dynamics and productivity of reefs. Results showed distinct variations in plankton biomass and assemblage from offshore to reef areas, as well as between the reef systems. Phytoplankton distributions pointed toward filtering out of cells across the fore reef and reef flat areas, while mesozooplankton distributions could be mediated more by other factors. Isotopic signatures of δ13C and δ15N indicated the influence of different nutrient sources for phytoplankton and that mesozooplankton relied only partly on phytoplankton for food in most areas of the reefs. The mesozooplankton likely also obtain food from other sources such as the microbial and detrital pathways. More in-depth spatio-temporal studies on these bentho-pelagic interactions are recommended, which can provide more robust estimates of the trophic dynamics of these reefs that are situated in important fishing grounds and key biodiversity areas.We thank Cesar Villanoy and the Physical Oceanography laboratory for organizing the research cruise, the Philippine Navy and the BRP Gregorio Velasquez (AGR 702) for the help in sample collection during the research expedition conducted in the Kalayaan Group of Islands in 2017. We also thank the Department of Science and Technology – Philippine Nuclear Research Institute for the collaboration in conducting the stable isotope analyses, John Kristoffer Q. Andres for identifying the zooplankton samples, and John Michael N. Aguilar for analyzing the samples for chemical parameters.
- Utility of low-cost recreational-grade echosounders in imaging and characterizing bubbly coastal submarine groundwater dischargeGabuyo, Mary Rose P.; Siringan, Fernando P. (Elsevier, 2022-01)Despite the growing knowledge on the significance of submarine groundwater discharge (SGD), mapping its occurrence is a continuing challenge. This study explores the capability and applicability of low-cost, off-the-shelf, recreational-grade echosounders (RGESs) to image different types and locate point sources of bubbly coastal SGD. Standard and systematic methodologies for efficient imaging and processing were established. The use of RGES was validated using a research-grade side scan sonar (RGSSS), continuous resistivity profiling, conductivity-temperature-depth casting, and MantaCam and SCUBA diving surveys. Lower frequencies (77/83 kHz) of RGESs showed more distinct acoustic signatures of bubbly SGD, as these were nearly the same as the effective resonance frequency of the bubbles. The clusters of bubbly discharges have higher backscatter strength than the water column noise, resulting in the definitive and convenient manual detection of SGD features. Hence, showing more accurate point sources of SGD. Three types of known SGD occurrence were identified and characterized based on acoustic behavior and spatial distribution: 1) sparse, discrete and sporadic discharge over wide area, 2) curtain, high and continuous bubble concentrations from widespread discharge, and 3) spring, direct bubble discharge from intense seafloor degassing at a single point source. These results showed that RGES provides a good alternative for more efficient and cost-effective preliminary coastal SGD works. Additional research on areas with water-dominated discharge but no bubbling is recommended.