5:15 PM - 7:15 PM
[ACG51-P07] Long-term Effect Assessment of Sunscreen Ingredients on Corals Using Compact Aquariums
Keywords:Corals, UV filters, Chlorophyll fluorescence measurements, Chronic toxicity, Aquarium experiment
Coral reefs are among the most biodiverse ecosystems on Earth. In recent years, many coral reefs have been exposed to the risk of bleaching and degradation due to both natural and anthropogenic influences. One such anthropogenic concern is the toxicity of sunscreen agents that are released into the marine environment. In fact, the state of Hawaii has banned sunscreens containing certain chemicals (e.g., oxybenzone and octinoxate), leading to the demand for alternative products. At the same time, research on the toxic effects of sunscreen ingredients on corals has been actively conducted.
One common approach to evaluating the impact of sunscreen ingredients on corals is short-term exposure experiments, in which corals are exposed to sunscreen components for a limited duration (48–96 hours). In these experiments, coral bleaching caused by stress responses is often used as an indicator of the acute toxicity of chemical substances. However, in natural environments, corals are likely exposed to lower concentrations of sunscreen ingredients over extended periods. Therefore, it is essential to assess the chronic toxicity of these chemicals through long-term experiments.
In this study, we aimed to evaluate the long-term effects of sunscreen ingredients on corals by exposing them to these substances under controlled conditions in multiple small-scale aquariums. By individually maintaining coral samples in separate small tanks, we sought to minimize the risk of mortality due to infectious diseases while enabling detailed measurements of coral responses to prolonged and stepwise chemical exposure.
For the experiment, a single coral colony (Acropora sp.) with a diameter of approximately 10 cm was fragmented into 18 pieces, each housed in an individual small tank. The tanks were divided into six groups, each consisting of three tanks exposed to a different test chemical, while one group served as a control (no additives). The environmental conditions, including water temperature, light/dark cycles, salinity, and water exchange frequency, were standardized across all groups. Over a one-month period, chlorophyll fluorescence measurements and image capture were conducted twice a week to evaluate the effects of each test substance on coral health. Chlorophyll fluorescence measurements were used to determine the maximum quantum yield of photosystem II in symbiotic zooxanthellae, serving as an indicator of coral bleaching. Additionally, visual assessments were conducted during image capture to monitor coral health. The experimental results revealed significant differences between the control group and the groups exposed to the test chemicals. In coral samples that exhibited stress responses, the maximum quantum yield in chlorophyll fluorescence measurements gradually declined with increasing exposure to the chemicals, indicating progressive bleaching.
In this presentation, we will discuss the utility and future potential of compact aquarium experiments for assessing the long-term effects of sunscreen ingredients on corals, based on the results.
One common approach to evaluating the impact of sunscreen ingredients on corals is short-term exposure experiments, in which corals are exposed to sunscreen components for a limited duration (48–96 hours). In these experiments, coral bleaching caused by stress responses is often used as an indicator of the acute toxicity of chemical substances. However, in natural environments, corals are likely exposed to lower concentrations of sunscreen ingredients over extended periods. Therefore, it is essential to assess the chronic toxicity of these chemicals through long-term experiments.
In this study, we aimed to evaluate the long-term effects of sunscreen ingredients on corals by exposing them to these substances under controlled conditions in multiple small-scale aquariums. By individually maintaining coral samples in separate small tanks, we sought to minimize the risk of mortality due to infectious diseases while enabling detailed measurements of coral responses to prolonged and stepwise chemical exposure.
For the experiment, a single coral colony (Acropora sp.) with a diameter of approximately 10 cm was fragmented into 18 pieces, each housed in an individual small tank. The tanks were divided into six groups, each consisting of three tanks exposed to a different test chemical, while one group served as a control (no additives). The environmental conditions, including water temperature, light/dark cycles, salinity, and water exchange frequency, were standardized across all groups. Over a one-month period, chlorophyll fluorescence measurements and image capture were conducted twice a week to evaluate the effects of each test substance on coral health. Chlorophyll fluorescence measurements were used to determine the maximum quantum yield of photosystem II in symbiotic zooxanthellae, serving as an indicator of coral bleaching. Additionally, visual assessments were conducted during image capture to monitor coral health. The experimental results revealed significant differences between the control group and the groups exposed to the test chemicals. In coral samples that exhibited stress responses, the maximum quantum yield in chlorophyll fluorescence measurements gradually declined with increasing exposure to the chemicals, indicating progressive bleaching.
In this presentation, we will discuss the utility and future potential of compact aquarium experiments for assessing the long-term effects of sunscreen ingredients on corals, based on the results.