| 摘要: |
| 陆基规模化海水养殖活动对近岸牡蛎礁贝床生态系统会产生多方面潜在的影响。本文基于碳氮稳定同位素技术研究了海南岛潮间带牡蛎礁牡蛎的食物来源及牡蛎对近岸陆源养殖尾水有机颗粒物（WPOM）的同化效率。选取儋州海头、昌江昌化、文昌龙楼3个受影响的天然牡蛎礁区（效应区）及昌江海尾未受影响的牡蛎礁区（对照区），对比分析了2022年7月（夏季）和11月（冬季）牡蛎的食物来源组成。结果表明，各站位牡蛎食物来源主要有底栖微藻、浮游植物、沉积物、养殖尾水有机颗粒物和大型海藻碎屑，它们对牡蛎的平均相对贡献率分别为33.8%±16.1%、15.4%±7.0%、24.4±21.8%、12.5%±4.2%、18.68%±19.9%，相对贡献率范围分别为12.9%?60.2%、8.6%?30.8%、0%?76.9%、6.0%?19.2%和0%?50.8%。其中，底栖微藻的最高贡献率出现在11月的龙楼，最低贡献率出现在11月的海尾；7月匍枝马尾藻（Sargassum polycystum）来源有机质对海尾牡蛎的食物贡献率高达50.8%；11月各站位沉积物食物贡献率均高于7月。效应区牡蛎7月的δ13C值分别为-16.48‰、-18.35‰、-17.06‰，11月分别为-15.15‰、-18.05‰、-15.22‰，均低于相应季节的对照区海尾（-15.65‰，-14.48‰）。7月海头与龙楼养殖尾水有机颗粒物对牡蛎的食物贡献率分别为15.3%、12.9%，明显高于11月（9.5%，6.0%）；7月，养殖尾水有机颗粒物对昌化牡蛎的食物来源贡献率为11.8%，低于11月（19.2%）。研究表明，养殖尾水有机颗粒物能有效地被牡蛎同化，是效应区牡蛎食物来源的重要补充。本研究证实天然牡蛎礁可同化去除一定比例的养殖尾水有机颗粒物，发挥其显著的生物修复作用，因此建议在减少陆源养殖尾水排放量的同时，大力保护或修复近岸牡蛎礁，降低邻近海域的营养负荷，保护海洋生态系统。 |
| 关键词: 牡蛎 稳定同位素 食物来源 水产养殖尾水 有机颗粒物 |
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| Food source of the oyster on natural oyster reef and ecological benefit assessment in the tropical intertidal zone of Hainan Island |
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Xiao Yu Lin, Shi Kai, Sun Chunyang, Jia Chenghao, Xu Qiang
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Hainan University
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| Abstract: |
| Land-based large-scale mariculture activities have many potential impacts on the ecosystem of oyster reef near the shore. Based on the stable isotope technique of carbon and nitrogen, this paper studied the food source of oyster on natural oyster reefreef in intertidal zone of Hainan Island and the assimilation efficiency of oyster to organic particulate matter (WPOM) in theof coastal aquatic farm effluentstail water (WPOM) of coastal land-based aquaculture. Three affected natural oyster reefs (effect areas) in Haitou of Danzhou, Changhua of Changjiang and Longlou of Wenchang and unaffected oyster reefs (control areas) in Haiwei of Danzhou in Haitou of Danzhou, Changhua of Changjiang and Longlou of Wenchang were selected, and the food source of oysters in July (summer) and November (winter) in 2022 was comparatively analyzed. The results show that the main food sources of oysters at each station were benthic microalgae, phytoplankton, sediments, organic particles in of aquatic farm effluents of aquaculture and macroalgae debris, and their average relative contribution rates to oysters were 33.8%± 16.1%, 15.4%± 7.0%, 24.4± 21.8%, 12.5%± 4.2% and 18.68%±19.9% respectively. The relative contribution rates ranged from 12.9% to 60.2%, 8.6% to 30.8%, 0% to 76.9%, 6.0% to 19.2%, and 0% to 50.8%, respectively. Among them, the highest contribution rate of benthic microalgae appeared in Longlou in November, and the lowest contribution rate appeared in Haiwei in November; In July, the contribution rate of organic matter from Sargassum polycystum to oysters of Haiwei was as high as 50.8%. The contribution rate of sediment food at each station in November was higher than that in July. The δ13C of the oyster in the effective area were -16.48‰, -18.35‰ and -17.06‰ in July, and -15.15‰, -18.05‰ and -15.22‰ in November, respectively, which were lower than those in the control area (15.65‰ and 14.48‰) in corresponding seasons. In July, the contribution rate of organic particles in the aquatic farm effluents of Haitou and Longlou culture to oyster food was 15.3% and 12.9%, respectively, which was significantly higher than that in November (9.5% and 6.0%). In July, the contribution rate of organic particles in aquatic farm effluents of aquaculture to oyster food source of Changhua was 11.8%, which was lower than that in November (19.2%). The research shows that the organic particles in aquatic farm effluents of aquaculture can be effectively assimilated by oysters, which is an important supplement to the food source of oysters in the effective area. This study confirms that natural oyster reefs can assimilate and remove a certain proportion of organic particles in aquatic farm effluents of aquaculture, and play a significant role in bioremediation. Therefore, it is suggested that while reducing the discharge of land-based cultured aquatic farm effluents, we should vigorously protect and repair the nearshore oyster reefs to, reduce the nutritional load in the adjacent waters, and protect the marine ecosystem. |
| Key words: oyster stable isotope food source aquatic farm effluents organic particulate matter |