講演情報
[AOS26-P10]Effects of warming on the thermal tolerance of six coralline algae from the largest subtropic intertidal algal reef ecosystem
*Yu-Tsen Huang1、Shan-Hua Yang1、Shao-Lun Liu2 (1.Inst. Fish. Sci., Natl. Taiwan Univ.、2.Dept. Life Sci. & Ctr. Ecol. Environ., Tunghai Univ.)
キーワード：
Ocean Warming、Algae Reef、Coralline Algae、Intertidal area
Taoyuan Algal Reef (TAR) that is mainly concreted by non-geniculated coralline algae (NGCA) is the largest and rare subtropical algal reef system. This habitat experiences high turbidity and seasonal sediment burial, which has filtered out most species, leaving lower diversity dominated by cryptic NGCA. In recent decades, climate change has intensified, and habitat-forming foundation species such as corals and large brown algae have been severely impacted. However, empirical evidence on the physiological tolerance of NGCA to ocean warming remains unexplored, particularly for the TAR that is situated in the coastal region and experiences a much higher rate of warming than surrounding regions. To address this, we conducted controlled aquarium experiments to examine the thermal tolerance of six common TAR NGCA species over two-month treatments at four different temperature settings as follows: a control at the Maximum Monthly Mean (MMM = 30 degrees Celsius) and three warming treatments (+2 degrees, +4 degrees, +6 degrees). Photosynthetic performance (Fv/Fm) was measured weekly, and pigment change and mortality were assessed using standardized color-card photography. Our results indicate that all species maintained photosynthetic performance and coloration under MMM +2 degrees (32 degrees Celsius). Notably, at MMM +4 degrees (34 degrees Celsius), only two NGCA species from the high intertidal zone, Chamberlainium sp. and Phymatolithon sp., maintained healthy Fv/Fm and coloration comparable to the control, with no significant differences detected. Under MMM +6 degrees (36 degrees Celsius), these two species still exhibited moderate to high survival. Our findings provide insights into the vulnerability and resilience of intertidal algal reef under ocean warming.