International Journal of Marine Science, 2025, Vol.15, No.4, 199-208 http://www.aquapublisher.com/index.php/ijms 205 7 Actual Case Analysis 7.1 Papua new guinea volcanic Yongquan district: sea cucumber community under natural low pH environment There is a natural CO₂ leak in the seabed near Dobu Island in Papua New Guinea, which has maintained the pH of the sea water in the sea for a long time at a low level of about 7.7~7.8. This environment provides a natural experimental field for studying the effects of marine acidification. According to on-site investigation, in this low-pH coral reef area, non-calcium-dependent organisms such as sea cucumbers and sea urchins still exist in large quantities, while many highly calcified species such as shrimp and crabs are almost extinct (Pichler et al., 2019). Sea cucumbers living in this area did not show obvious abnormal behavior: they still feed, move, and inhabit normally, with only slightly different population density and composition from the surrounding normal areas. It is speculated that sea cucumbers can survive in this acidification environment, thanks to their low calcification needs and strong acid-base regulation capabilities in the body. However, the ecology of the region has changed overall: coral cover and diversity decline, algae breeding and invertebrate “weed” organisms dominate (Geissler et al., 2021). As a residual functional group, sea cucumbers continue to play the role of sediment cleaning and nutrient regeneration to a certain extent, but cannot stop the tendency of coral reef decline. This case shows that sea cucumbers are relatively tolerant of acidification stress, and their ecological function is more important in the upheaval of environmental changes. 7.2 Philippine sea farming experiment: sea cucumber farming performance under acidification conditions To evaluate the impact of marine acidification on sea cucumber farming, researchers in the Philippines conducted simulated farming experiments on tropical sea cucumber larvae. In this experiment, ginseng was exposed to water bodies that lowered 0.3 units of pH (approximately 7.8) and raised 3 °C for 5 days to observe its feeding and growth status. The results showed that the feeding vitality and nocturnal activity of sea cucumbers under low pH conditions did not show a significant decrease, while the control luminescent spiral activity decreased significantly under the same conditions. More importantly, after several days of domestication, there was no significant difference in feeding rate and growth rate between different treatment groups, whether it was sea cucumbers or luminous snails (Figure 3) (Campo et al., 2022). This shows that sea cucumbers have strong short-term acidification adaptability: their feeding and growth can be adjusted and restored in a short period of time even in seawater at pH 7.8 (Yuan et al., 2016). This experiment provides inspiration for the breeding industry: under the future marine acidification scenario, tropical sea cucumbers may still maintain a high survival rate and growth efficiency. However, the study also emphasized that corresponding measures need to be taken according to different species, such as selecting sea cucumber varieties with stronger acid resistance and optimizing aquaculture water quality to improve the risk resistance of seawater aquaculture to acidification (Campo et al., 2022). 8 Coping and Prospect Ocean acidification has had a certain impact on the physiology and behavior of tropical sea cucumbers, but its degree and performance are complex. Sea cucumbers have strong physiological regulation capabilities and can maintain basic functions under moderate acidification, but in severe acidification situations, negative effects such as reduced feeding and increased metabolic burden may still occur. The weakening of the ecological function of sea cucumber will impact the coral reef ecosystem through nutrient circulation and other links, which requires attention. Faced with the continuous advancement of marine acidification, it is of great significance to conduct in-depth research on the adaptability potential and population differences of tropical sea cucumbers. On the one hand, there are differences in tolerance to acidification in different sea cucumber species and developmental stages: studies have shown that adult sea cucumbers are relatively tolerant to the predicted acidification levels in the near future, but the larval stage often exhibits higher vulnerability (such as delayed development and reduced survival). Revealing the genetic and physiological mechanisms of these differences can help predict which populations are more susceptible to shocks and develop targeted protection strategies. On the other hand, in the field of
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