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| 海南岛热带潮间带天然牡蛎礁牡蛎食物来源及其生态效益评估 |
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肖玉林1,2,3, 施凯1,2, 孙春阳2,4, 贾程豪2,4, 许强1,2
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1.海南大学海洋生物与水产学院, 海南 海口 570228;2.海南大学南海海洋资源利用国家重点实验室, 海南 海口 570228;3.广东省农业科学院农业经济与信息研究所, 广东 广州 510640;4.海南大学生态与环境学院, 海南 海口 570228
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| 摘要: |
| 陆基规模化海水养殖活动对近岸牡蛎(Ostreidae)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%±16.5%、15.5%±6.9%、24.1±21.7%、13.0%± 3.4%、26.6%±16.4%, 相对贡献率范围分别为12.9%~61.6%、7.8%~30.8%、0%~76.9%、9.3%~19.2%和0%~45.0%。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45.0%; 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%, 9.3%); 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(Ostreidae) 稳定同位素 食物来源 水产养殖尾水 有机颗粒物 |
| DOI：10.11759/hykx20240303001 |
| 分类号:Q89 |
| 基金项目:海洋牧场生态农牧化模式构建与示范项目(2022YFD2401305);海洋牧场资源动态预测与可持续利用模式(2019YFD0901304) |
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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 Yulin1,2,3, SHI Kai1,2, SUN Chunyang2,4, JIA Chenghao2,4, XU Qiang1,2
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1.School of Marine Biology and Fisheries, Hainan University, Hainan 570228, China;2.State Key Laboratory of Marine Resources Utilization in South China Sea, Hainan University, Hainan 570228, China;3.Institute of Agricultural Economics and Information, Guangdong Academy of Agricultural Sciences, Guangzhou 510640, China;4.College of Ecology and Environment, Haikou, Hainan University, Hainan 570228, China
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| Abstract: |
| Land-based large-scale mariculture activities have substantial potential impacts on the ecosystems of nearshore oyster reefs. This study investigates the food sources for oysters on natural oyster reefs in the intertidal zone of Hainan Island using stable isotopes of carbon and nitrogen to determine the assimilation efficiency of oysters to organic particulate matter from coastal aquatic farm effluents. The study focused on three affected natural oyster reefs (effect areas) in Haitou of Danzhou, Changhua of Changjiang, and Longlou of Wenchang, as well as unaffected oyster reefs (control areas) in Haiwei of Danzhou. The food source of oysters was comparatively analyzed in July (summer) and November (winter) in 2022. Results revealed that the main food sources of the oysters were benthic microalgae, phytoplankton, sediments, organic particles from aquatic farm effluents, and macroalgae debris. Moreover, their average relative contribution rates to oyster diets were 33.8% ±16.5%, 15.5% ±6.9%, 24.1% ±21.7%, 13.0% ±3.4%, and 26.6% ±16.4% respectively. The relative contribution rates ranged from 12.9% to 61.6%, 7.8% to 30.8%, 0% to 76.9%, 9.3% to 19.2%, and 0% to 45.0%, respectively. Specifically, the highest contribution rate of benthic microalgae was observed in Longlou in November, whereas the lowest was in Haiwei in November. In July, contribution rate of organic matter from Sargassum polycystum to oysters in Haiwei reached 45.0%. The contribution rate of sediment food in November was higher than that in July across all stations. The δ13C values of oysters in the effective areas were −16.48‰, −18.35‰, and −17.06‰ in July, and −15.15‰, −18.05‰, and −15.22‰ in November, which were lower than those in the control area (15.65‰ and 14.48‰) in corresponding seasons. In July, the contribution rates of organic particles from aquatic farm effluents to oyster food in Haitou and Longlou were 15.3% and 12.9%, respectively, which was significantly higher than those in November (9.5% and 9.3%). In Changhua, the contribution rate of organic particles was 11.8% in July, which increased to 19.2% in November. The research shows that oysters can effectively assimilate organic particles from aquatic farm effluents, making these particles an important supplement to the food source of oysters in the effective area. Thus, this study confirms that natural oyster reefs can assimilate and remove a certain proportion of organic particles in aquatic farm effluents of aquaculture, highlighting their role in bioremediation. Therefore, it is suggested that efforts must be made to reduce the discharge of land-based cultured aquatic farm effluents, vigorously protecting and restoring nearshore oyster reefs to help reduce the nutritional load in adjacent waters and protect the marine ecosystem. |
| Key words: oyster stable isotope food source aquatic farm effluents organic particulate matter |
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