Arctic lagoon and nearshore food webs: Relative contributions of terrestrial organic matter, phytoplankton, and phytobenthos vary with consumer foraging dynamics
Arctic lagoon and nearshore food webs: Relative contributions of terrestrial organic matter, phytoplankton, and phytobenthos vary with consumer foraging dynamics
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DOI：
10.1016/j.ecss.2021.107388
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发表时间：
2021-08
期刊：
影响因子：
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通讯作者：
K. McMahon;W. Ambrose;M. J. Reynolds;Beverly J. Johnson;A. Whiting;L. Clough
中科院分区：
文献类型：
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作者：
K. McMahon;W. Ambrose;M. J. Reynolds;Beverly J. Johnson;A. Whiting;L. Clough
描述能量流和营养联系对于了解北极生态系统在气候变化和人类开发日益增加的压力下的功能和恢复力至关重要。我们使用碳和氮稳定同位素来研究营养动态以及陆生有机质、水柱浮游植物和底栖植物的相对贡献（底栖微型和大型自养生物以及海冰藻类）的食物网支持45个大型消费者在三个北极沿海泻湖生态系统（Krusenstern，Sisualik，Akulaaq）和相邻的Kotzebue Sound，在阿拉斯加的Krusenstern角国家纪念碑有不同程度的连通性。一个双源（水柱颗粒有机物和底栖沉积物有机物），两个同位素营养动力学模型告知贝叶斯同位素混合模型显示，泻湖Kotzebue声音沿海生态系统支持消费者沿着从初级消费者，包括端足类，桡足类，蛤蜊的营养级5捕食者，如海星，食鱼鱼类，海豹和海鸟的营养位置连续。三个初级生产者终端成员，陆地有机质（41 ± 21%），浮游植物（25 ± 21%）和底栖植物（34 ± 23%）的相对贡献变化的功能：1）消费者觅食生态和2）消费者的位置。浮游动物的碳主要来自浮游植物（49 ± 11%）和陆地有机物（23 ± 5%）的食物网，而食草动物和反食草动物的碳主要来自底栖植物的食物网，分别为58 ± 10%和60 ± 8%。杂食动物和捕食者表现出更均匀的资源依赖分布和更大的物种间的整体差异。在无脊椎动物中，随着营养地位的增加，陆地有机物的重要性下降，而植物底栖动物的重要性增加。陆地有机物贡献的重要性增加泻湖接近主要河流的输入和隔离Kotzebue声音。对当地社区具有文化和生计食物重要性的几个类群显示出对与新鲜陆地有机物有关的食物链的显著依赖（基线碳的30-90%）。我们的研究表明，陆地-海洋联系对北极沿海泻湖生态系统和手工渔业的功能很重要。随着与气候变化和人为干扰有关的侵蚀和径流的区域变化，这些联系今后可能会加强。
Characterizing energy flow and trophic linkages is fundamental to understanding the functioning and resilience of Arctic ecosystems under increasing pressure from climate change and anthropogenic exploitation. We used carbon and nitrogen stable isotopes to examine trophic dynamics and the relative contribution of terrestrial organic matter, water column phytoplankton, and phytobenthos (benthic micro- and macro-autotrophs as well as sea ice algae) to the food webs supporting 45 macroconsumers in three Arctic coastal lagoon ecosystems (Krusenstern, Sisualik, Akulaaq) and the adjacent Kotzebue Sound with varying degrees of connectivity in Cape Krusenstern National Monument, Alaska. A two-source (water column particulate organic matter and benthic sediment organic matter), two-isotope trophic dynamics model informed by a Bayesian isotope mixing model revealed that the Lagoon-Kotzebue Sound coastal ecosystem supported consumers along a trophic position continuum from primary consumers, including amphipods, copepods, and clams to trophic level five predators, such as seastars, piscivorous fishes, seals, and seabirds. The relative contribution of the three primary producer end members, terrestrial organic matter (41 ± 21%), phytoplankton (25 ± 21%), and phytobenthos (34 ± 23%) varied as a function of: 1) consumer foraging ecology and 2) consumer location. Suspension feeders received most of their carbon from food webs based on phytoplankton (49 ± 11%) and terrestrial organic matter (23 ± 5%), whereas herbivores and detritivores received the majority of their carbon from phytobenthos-based food webs, 58 ± 10% and 60 ± 8%, respectively. Omnivores and predators showed more even distributions of resource reliance and greater overall variance among species. Within the invertebrates, the importance of terrestrial organic matter decreased and phytobenthos increased with increasing trophic position. The importance of terrestrial organic matter contribution increased with lagoon proximity to major rivers inputs and isolation from Kotzebue Sound. Several taxa with cultural and subsistence food importance to local communities showed significant reliance (30–90% of baseline carbon) on food chains linked to fresh terrestrial organic matter. Our study indicates that terrestrial-marine linkages are important to the function of Arctic coastal lagoon ecosystems and artisanal fisheries. These linkages are likely to strengthen in the future with regional changes in erosion and runoff associated with climate change and anthropogenic disturbance.