UROP Proceedings 2020-21

School of Science Department of Ocean Science 63 Characterising Coral Reef Function across Anthropogenic Gradients Supervisor: WYATT Alex / OCES Student: ABBAS Rauszen Ocean Annika / SSCI Course: UROP1100, Fall This study has investigated how benthic composition can affect oxygen concentration and net ecosystem production at 3 sites in Palau. Ranging from sand to coral and algae dominated ecosystems, the gradient flux approach was adopted to record oxygen from two heights above the seafloor for 24 hours. A relationship was found that showed that changes in coral and algae coverage resulted in different oxygen production and respiration. The findings reveal how benthic autotrophs can influence the net ecosystem production of coral reefs and why it is vital to better understand how organisms play a part in primary production and how we may predict reef trends in the future. Characterising Coral Reef Function across Anthropogenic Gradients Supervisor: WYATT Alex / OCES Student: CHU Yui Kei / BCB Course: UROP1100, Fall Coral could be easily damaged by anthropogenic activities and bleaching events. Reduction in percentage coverage of coral over the benthic surface might affect primary productivity and respiration in coral reef. Net ecosystem production (NEP) were measured at five sites in Palau: A1, A4, B1, B4 and L3 through the gradient flux approach. A1 and A4 are coral-dominated reef; B1 and B4 were algal reef and L3 was a sanddominated reefs. The result points to a possible reduction in respiration rate over coral community as coral reefs transform into algal reefs. The respiration rate of reef during night-time might become more stable. However, the impact over the primary productivity over the reef could not be determined. Characterising Coral Reef Function across Anthropogenic Gradients Supervisor: WYATT Alex / OCES Student: CHUNG Shun Lap Benedict / ENVS Course: UROP1100, Fall There have been ongoing efforts in coral reef research aiming to understand and protect these visually appealing ecological sanctuaries, under the ever-elevating pressures from innumerable artificial impacts on the marine environment. Sensor monitoring methods for measuring reef metabolic data are often a useful non-invasive, and continuous tool in deciphering the health condition of reef ecosystems. So, this report aims to deliver a trial observation of the net ecosystem productivity (NEP) over several reef sites surrounding Palau. The NEP computation made use of the technique of measuring the oxygen gradient flux released from the primary productivity of the boundary phase of the benthic reef community, in a vertical profile, adapted from Takeshita et al., 2016. Finally, we will discuss the observations made there and its possible implication with reef systems and its species compositions.

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