Background: In the Philippines, the practice of planting mangroves over seagrass has been a practice done to promote coastline protection from damages done by storms. Despite the added protection to the coastline, the addition of an artificial ecosystem gradually inflicts damage to the ecosystem already established. In this study, seagrass communities that had no history of mangrove planting were compared with those that had mangrove planting. The percent substrate cover of seagrass in the sampling areas was determined, and the macroinvertebrates present in the sampling areas were also observed. The study was conducted based on reports of mangrove planting activity that disrupted seagrass functions on Santa Fe, Bantayan Island, Cebu. Transectquadrat method sampling was done to assess the chosen sites. Results: Six species of seagrass was found on the site without mangrove planting which was barangay Ocoy (Cymodocea sp., Thalassia sp., Halodule sp., Enhalus sp., Halophila sp., and Syringodium sp.) and had a higher percent cover, while only four were found on the site with mangrove planting (barangay Marikaban). It was also found that barangay Marikaban had a lesser Shannon-Wiener and Simpson's index compared to barangay Ocoy. Jaccard's index of similarity between the two sites was low. Conclusion: With the results of the assessment, we recommend proper monitoring of future mangrove planting activities and that these activities should not disrupt another ecosystem as all ecosystems are important.

Biosurfactants are amphipathic compounds that are useful in industries and are also used in bioremediation. Rhamnolipids (RL) are biosurfactant mostly produced by the genus Pseudomonas. This study screened 6 strains of Pseudomonas isolated from underwater cave sediments to determine if they were capable of producing rhamnolipids. The biosurfactant production of potential strains was screened by Parafilm-M Test, Oil spreading technique, Microplate assay, Emulsification Index, CTAB Agar plate method, Anthrone test, and Thin Layered Chromatography. The study showed that only 3 strains had the potential to produce rhamnolipids, these were Pseudomonas poae, Pseudomonas fluorescens and Pseudomonas libanensis. The antimicrobial activity of the crude rhamnolipid extracts was tested against two Gram-negative bacteria (Escherichia coli, Serratia marcescens) and two Gram-positive bacteria (Bacillus cereus, Staphylococcus aureus) by the conventional minimum  inhibitory concentration (MIC). The antioxidant activity of the crude rhamnolipid extracts was determined through DPPH free radical scavenging assay. All rhamnolipid extracts had a positive correlation between increasing concentrations and the zone of inhibition against test microorganisms. Rhamnolipids from P. libanensis had the lowest MIC among the other extracts, indicating its potency against the test bacteria. The rhamnolipid extracts were effective at inhibiting the test bacteria compared to the positive control, Nitrofurantoin. The antioxidant activity of the crude rhamnolipid extracts was determined through DPPH. Crude rhamnolipid extracts exhibited antioxidant activity but not as great as that of ascorbic acid.