Effects Of Light On The Distributions, Photosynthesis And Recovery Of Halophila ovalis (R. Br.) Hook. f. In Pulau Korea (Pulau Gazumbo), Penang
| dc.contributor.author | Jonik, Michelle Glory G | |
| dc.date.accessioned | 2022-08-15T04:18:26Z | |
| dc.date.available | 2022-08-15T04:18:26Z | |
| dc.date.issued | 2020-04 | |
| dc.description.abstract | From the 72 global species diversity of seagrass, there are 16 species from different genera were recorded throughout the 78 sites in Malaysia. To date, there are six seagrass habitats reported in the northern region of Peninsular Malaysia and one of it is this study site, Pulau Korea, Penang. The study site is rich in biodiversity with a significant number of coastal communities relying on it for their livelihood. However, Penang Island is a highly urbanised city state in Northern region of Malaysia and Penang States Development Corporation had proposed to reclaim Pulau Korea. Despite all the coastal developments adjacent to the study site which will disrupt the water quality, there have been limited studies of seagrass conditions in terms of photo-physiology nor the recent distribution are since year 2016. Thus, this study was to provide an updated report on the distribution, biomass and photo-physiology of Halophila ovalis in the intertidal zone of Pulau Korea. The distribution was estimated based on seagrass percentage cover, while the health of seagrass was monitored through the photo-physiological performance by using chlorophyll fluorescence technique. The findings indicated that the total estimated area of seagrass area in Pulau Korea was approximately 4.49 acres (39.8 ± 2.03%) and was classified as moderate coverage with Braun-Blanquet scale score 3. However, seagrass population in Pulau Korea was low, with only 3 identified seagrass species (H. ovalis as the dominant seagrass, H. beccarii and Enhalus acoroides) as compared with other seagrass bed in Merambong, Johor that have more seagrass species. The distribution variation of H.ovalis over 11 months in Pulau Korea was negatively influenced by temporal changes in light intensity (R² = -0.135). No significant influence (P > 0.05) from all the environmental parameters was observed in biomass and morphology growth characteristics of H. ovalis except for leaf length that were influenced by nitrite (R² = 0.114), nitrate (R² = 0.135) and ammonia (R² = 0.044). Variations in Fv/Fm of H. ovalis was influenced by the light intensity (R² = -0.171). While, ΔF/Fm' was influenced by light intensity (R² = 0.234) and temperature (R² = 0.061). rETRmax and α of H. ovalis were positively influenced by water temperature (R² = 0.112) and light intensity (R² = 0.168) respectively. Meanwhile significant influence from the light intensity (R² = 0.091), water temperature (R² = 0.053), TSS in water column (R² = -0.051) and chlorophyll content (R² = -0.066) have resulted in variations of Ek. Moreover, seagrasses are often exposed to different light regimes due to tidal changes. During low tide, intertidal seagrasses are highly vulnerable to thermal stress, desiccation and photodamage due to prolonged exposure. Therefore, to understand the survival mechanism of seagrass in Pulau Korea and its overall resilience ability to recover from light stress, a dark-recovery analysis was conducted under high-light (HL) and low-light (LL) exposure. Findings show that, throughout the 6 hours exposure to HL treatment (1052.7 – 2572.7 μmol photon mˉ² sˉ¹) H. ovalis showed high NPQ values (2.592 – 3.464) which required 15 to 30 minutes dark-recovery period to achieve high Fo values and high Fv/Fm (0.735 – 0.854) with reduced NPQ (1.286 – 3.065) by 30%. Under LL treatment (61.9 – 84.6 μmol photon mˉ² sˉ¹), regardless of the prolonged exposure, 10 minutes dark-adaptation is sufficient for the recovery of H. ovalis reaction centre by having Fv/Fm values around 0.347 – 0.437 which are higher than the control (0 minute dark-recovery; Fv/Fm: 0.263 – 0.309). | en_US |
| dc.identifier.uri | http://hdl.handle.net/123456789/15823 | |
| dc.language.iso | en | en_US |
| dc.publisher | Universiti Sains Malaysia | en_US |
| dc.subject | Natural history | en_US |
| dc.title | Effects Of Light On The Distributions, Photosynthesis And Recovery Of Halophila ovalis (R. Br.) Hook. f. In Pulau Korea (Pulau Gazumbo), Penang | en_US |
| dc.type | Thesis | en_US |
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