Abstract Species of the family Sternoptychidae (hatchetfishes) occur worldwide and play critical roles by sequestering carbon, recycling nutrients, and acting as a key trophic link between epipelagic primary consumers and higher trophic levels in marine ecosystems. Nevertheless, basic knowledge on their ecology is still lacking and their functional ecology remains understudied with respect to composition, organization, functions and environment interactions. Here we integrated comprehensive information collected in the western Tropical Atlantic on the diversity, abundance, distribution and trophic ecology of hatchetfishes, including physicochemical features of their habitats and extensive carbon and nitrogen stable isotope data on its main prey groups. On this basis we defined five functional groups of hatchetfishes with different diet preference, isotopic composition, and vertical abundance peaks and reveal a possible high resource partitioning. Additionally, these species might have a different feeding tie chronology. Hence, hatchetfishes segregate in different ecological groups responding differently to environmental constraints including oxygen concentration and presenting diverse functional roles. As deep-sea species that migrate to epipelagic waters, hatchetfishes may play a key role in the transfer of sub-surface photoassimilated carbon to deeper waters, a pathway through which the effects of climate change at the surface are transferred to the deep ocean. Moreover, as consumers of gelatinous organisms, these species convert “gelatinous energy” into “fish energy” readily usable by higher trophic levels, including endangered and commercially important species. This is a crucial trophic relationship that has been historically underestimated due to methodology limitations (e.g., quickly digested gelatinous organisms were probably underestimated in previous studies, based solely on stomach contents). Considering in ecosystem models this trophic relationship, as well as the functional organization of hatchetfishes, is important to properly answer key ecological questions including resource use, carbon transportation, and influence of mesopelagic community in climate change process.

中文翻译：

---

Hatchetfishes (Stomiiformes: Sternoptychidae) 生物多样性、营养生态学、垂直生态位划分和热带大西洋西部的功能作用

摘要 Sternoptychidae (hatchetfishes) 家族的物种在世界范围内广泛存在，通过固碳、循环养分以及作为上层主要消费者与海洋生态系统中较高营养水平之间的关键营养联系而发挥着关键作用。然而，它们的生态学基础知识仍然缺乏，它们的功能生态学在组成、组织、功能和环境相互作用方面仍未得到充分研究。在这里，我们整合了在热带大西洋西部收集的有关斧头鱼多样性、丰度、分布和营养生态学的综合信息，包括其栖息地的物理化学特征及其主要猎物群的广泛碳和氮稳定同位素数据。在此基础上，我们定义了五种不同饮食偏好的斧头鱼功能组，同位素组成和垂直丰度峰值，并揭示了可能的高资源分配。此外，这些物种可能有不同的进食关系。因此，斧头鱼在不同的生态群体中分离，对包括氧气浓度在内的环境约束做出不同的反应，并表现出不同的功能作用。作为迁移到上层水域的深海物种，斧头鱼可能在将次表层光同化碳转移到更深水区方面发挥关键作用，这是将表层气候变化影响转移到深海的途径。此外，作为胶状生物的消费者，这些物种将“胶状能量”转化为“鱼类能量”，易于被更高的营养水平使用，包括濒危和具有商业重要性的物种。这是一种至关重要的营养关系，由于方法学的限制，历史上一直低估了这一关系（例如，在以前的研究中，仅根据胃内容物可能低估了快速消化的胶状生物）。在生态系统模型中考虑这种营养关系以及斧头鱼的功能组织，对于正确回答关键生态问题非常重要，包括资源利用、碳运输以及中层群落在气候变化过程中的影响。