三亚蜈支洲岛海洋牧场区域夏季食物网研究

The summer food web in the marine ranch area of Wuzhizhou Island in Sanya,Hainan

三亚蜈支洲岛海洋牧场在针对珊瑚礁修复工作、热带海洋牧场建设等方面取得了不错的效果,但海洋牧场区域的营养结构仍需要长期的监测评估。于2020年7月海洋生物调查共采集52种主要消费者,以碳(δ^(13)C)、氮(δ^(15)N)稳定同位素技术为基础,首次构建三亚蜈支洲岛海洋牧场区域食物网并进行研究。结果表明:(1)主要消费者的δ^(13)C值范围在-19.10‰--12.74‰之间,平均值为(-16.99±1.52)‰;δ^(15)N值范围为6.43‰-14.03‰,平均值(11.24±1.70)‰。单因素方差分析结果显示,不同类群之间碳氮稳定同位素均有显著性差异(P<0.01)。(2)大型海藻和底栖微藻对主要消费者的贡献率最大为41.50%,沉积有机物(SOM)和浮游植物也是消费者的重要碳源(贡献率分别为20.05%、19.97%),悬浮颗粒有机物(POM)对消费者的碳源贡献率最低,为18.48%。(3)三亚蜈支洲岛牧场区域主要消费者的营养级范围为1.53-3.76,主要消费者营养层次分布两端少,中间多。通过系统聚类分析发现,三亚蜈支洲岛牧场区域生态系统可以分为4种营养类群:第一类群主要由混合食性的底栖性鱼类以及头足类组成;第二类群主要是以底栖微藻为主,SOM为辅的虾蟹类构成;第三类群的食源以大型海藻为主,主要为肉食性鱼类;第四类群为SOM、底栖藻类食性的初级消费者(棘皮类和腹足类)。(4)应用SIBER模型分析三亚蜈支洲岛牧场区域生态系统的营养结构指标,与邻近海域的研究结果比较发现,牧场区域生态系统的摄食来源多样性水平(CR)、营养级长度(NR)、生态位总空间(TA)和平均营养级多样性程度(CD)相对较高;且研究海域食物网的营养冗余程度(MNND、SDNND)偏高。研究构建了三亚蜈支洲岛海洋牧场生态系统食物网,为了解该生态系统营养结构提供了基础资料和参考数据。

The marine ranching area of Wuzhizhou Island in Sanya has achieved good results in terms of coral reef restoration and tropical marine ranching construction,but the nutritional structure and stability of the ecosystem in the ranch area still need long-term monitoring and evaluation.Based on the stable isotope technology of carbon(δ^(13)C)and nitrogen(δ^(15)N),the regional food web of the Wuzhizhou Island Marine Ranching in Sanya was constructed and studied for the first time.In July 2020,the marine biology survey collected 52 major consumers.The results revealed that theδ^(13)C values of the dominant consumers ranged from-19.10‰to-12.74‰(with an average of(-16.99±1.52)‰).Theδ^(15)N values of the dominant consumers ranged from 6.43‰to-14.03‰(with an average of(11.24±1.70)‰).One-way analysis of variance(ANOVA)showed that the stable carbon and nitrogen isotopes of different groups were significantly different(P<0.01).The contribution rate of macroalgae and benthic microalgae to major consumers was 41.50%.Sedimentation organic matter(SOM)and phytoplankton were also important carbon sources for consumers(contribution rates are 20.05%and 19.97%respectively).Suspended particulate organic matter(POM)contributed the lowest carbon source to consumers by 18.48%.The nutritional level of the main consumers in the Wuzhizhou Island Ranch area in Sanya ranged from 1.53 to 3.76.The nutrition level of major consumers was less at both ends and more in the middle.Hierarchical cluster analysis showed 4 trophic groups in marine ranching area of Wuzhizhou Island in Sanya.The first group was mainly composed of mixed-feeding benthic fishes and cephalopods;the second group was shrimp and crabs eating mainly benthic microalgae,and SOM as the supplement;the food source of the thirdgroup was mainly macroalgae,especially carnivorous fish;the fourth group was SOM and primary consumers eating on benthic algae(e.g.echinoderms and gastropod).The SIBER model was used to analyze the nutritional structure indicators of the Wuzhizhou Island pasture ecosystem in Sanya.Compared with the results in the adjacent sea areas,it was found that the level of food source diversity(CR),trophic level length(NR),total area(TA)and mean distance to centroid(CD)were relatively high;and the nutritional redundancy(MNND,SDNND)of the food web in the research sea area was relatively high.This study initially constructed a food web for the marine ranching area of Wuzhizhou Island in Sanya to provide basic information and reference data for understanding the nutritional structure of the ecosystem.