Laboratory Cultivation of Selected Seagrass Species in Sagñay, Camarines Sur, Philippines

Date of Award

5-2022

Document Type

Thesis

Degree Name

Master of Science in Biology

First Advisor

Arni E. Gambe-Gilbuena, PhD

Abstract

Seagrass beds in Atulayan Bay, a marine protected area (MPA), is threatened and has declined substantially over the past 15 years. Environmental perturbations, both natural and man-made exacerbate this problem, underscoring the need to develop laboratory protocols for breeding seagrass. Thus, in this study in situ health and habitat conditions of endogenous seagrass species growing in an MPA were determined to identify laboratory conditions that are most favorable for growth. Seagrass bed mapping and sampling were done according to the line-transect quadrat method and seagrass- watch guide. While seagrass health was fair and habitat conditions were within the range preferred by aquatic organisms, acclimation trials in the laboratory showed a decline in the number of shoots. Halodule uninervis, which was the most prevalent species in the MPA, was transplanted to an aquarium tank system filled with artificial seawater and sediment. To simulate eutrophication, nutrient manipulation experiments were conducted; seagrass growth and survival responses were closely monitored. The growth of surviving plants in the aquarium tank system could be sustained for more than a month. Interestingly, the shoot count, number of leaf blades, leaf length and leaf area were strongly negatively correlated with the N+P water-column enrichment. At N+P concentrations between 200 to 2000 μM N, plant growth was reduced and at 20,000 μM N necrosis was observed. Future studies may be conducted to characterize the response of H. uninervis if the nutrient enrichment is applied to the sediment. There is a dearth of information on monitoring and breeding protocols for seagrasses particularly for endogenous seagrass species. This work may thus serve as reference for seagrass studies and as a guide in breeding native seagrass species, for conservation, restoration, and research purposes.

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