Page 36 - IPCoSME 2021

1 INTERNATIONAL POSTGRADUATE CONFERENCE ON SCIENCE AND MARINE ENVIRONMENT 2021
st
(IPCoSME 2021)
“Environmental Sustainability Enhancement Through the Collaboration of Sciences”

RD-04

PHYSIOLOGICAL INDICATORS OF CORAL HOLOBIONT, Pocillopora acuta
RESPONSES TO THERMAL AND LIGHT STRESSESTITLE

PIMRAK MOUNGKEAW , MATHINEE YUCHAROEN AND SUTINEE
1*
1
2
SINUTOK

1 Marine and Coastal Resources Institute, Faculty of Environmental Management and Coastal
Oceanography and Climate Change Research Center, Prince of Songkla University, Hatyai,
Songkhla, 90110 Thailand
2 Faculty of Environmental Management and Coastal Oceanography and Climate Change
Research Center, Prince of Songkla University, Hatyai, Songkhla, 90110 Thailand

*Corresponding author email: pimrak.mou@gmail.com

Abstract: Coral bleaching events in global and regional scales have seriously affected on coral
mortality and their ability to recover. There is spatial variability in bleaching response in Thai’s

water reefs based on their experience with thermal stress or environmental conditions. In
cellular scale, coral and its zooxanthellae would able to adapt or resist to higher sea surface

temperature. Hence, photosynthetic responses of P. acuta from different environments were
investigated under elevated temperature and light conditions. Coral nubbins from turbid and

non-turbid environment, Panwa Cape and Maiton Island, Phuket, Thailand were collected and

exposed to four treatments in wet lab: 1) ambient temperature, ambient light 2) ambient
temperature, high light intensity, 3) high temperature, ambient light, and 4) high temperature,

high light intensity. The experiment was conducted for 14 days of gradual temperature
increasing and decreasing. Photosynthetic performance, zooxanthellae density and chlorophyll

concentration were measured. Synergistic effects of heat and light stresses were observed on

P. acuta from both sites as shown in decreased maximum quantum yield and relative electron
transport rate, loss of zooxanthellae association and reduction of chlorophyll a and c2

concentrations. However, corals from turbid reef showed an ability to recover when
temperature was reduced. Therefore, we suggested that corals from Panwa Cape was more

resistant than Maiton under same stressors leading to difference capacity to survive after coral

bleaching event.

Keywords: coral bleaching, heat stress, light stress, PAM fluorometry, photosynthesis

36