Deep-sea offshore northwestern Cuba is the less studied zone of the Gulf of Mexico (GoM). Our study aimed to set an environmental baseline and investigate a potential west-east gradient of sediment properties and nematode diversity along the northwestern Cuba. Sediments were collected by multicorer at nine sites in the insular slope between 974 and 1682 m depth. Sediment texture and composition showed a west-east gradient caused likely by narrowing of shelf width and increasing of downslope transport of terrigenous material. We found clear signatures of heavy metal pollution likely derived from Havana City but also from open-sky mining (Castellanos mining complex) and port dredging operations (Mariel). Nematode assemblages were dominated by the deep-sea genera: Acantholaimus, Metadasynemella, Desmodorella, Cervonema, Daptonema, Halalaimus, and Pselionema. α-diversity was about 20–50 genera and γ-diversity of about 100 genera. The β-diversity was substantial likely because small-scale patchiness of resources and heavy metals stress that increased assemblage variability. Individual weight decreased with depth indicating food-supply limitation in the deep sea; also, heavy metals were negatively correlated with weight suggesting deleterious effects on the growing. Our findings indicate that heavy metal pollution has reached deep-sea sediments and corroborate the long-range effects of anthropogenic activities on deep sea. Taxonomic diversity and biological traits (life strategy and trophic composition) constituted a powerful bioindicator of benthic health and benchmark for future potential disturbances in the region. Northwestern Cuba slope is still an understudied portion of the GoM and more research is needed to fully understand its biodiversity and biogeochemical patterns.

古巴西北部近海深海是墨西哥湾 (GoM) 研究较少的区域。我们的研究旨在设定环境基线并调查古巴西北部沉积物特性和线虫多样性的潜在西东梯度。通过多芯钻机在 974 米至 1682 米深度之间的岛坡九个地点收集了沉积物。沉积物结构和成分呈现出东西向梯度，这可能是由于陆架宽度变窄和陆源物质下坡输送增加造成的。我们发现重金属污染的明显特征可能来自哈瓦那市，但也来自露天采矿（卡斯特利亚诺斯采矿综合体）和港口疏浚作业（马里尔）。线虫组合以深海属为主：Acantholaimus、Metadasynemella、Desmodorella、Cervonema、Daptonema、Halalaimus和Pselionema。α-多样性约为20-50属，γ-多样性约为100属。β-多样性很大，可能是因为资源和重金属的小规模斑块增加了组合变异性。个体体重随着深度的增加而减少，表明深海的食物供应有限；此外，重金属与体重呈负相关，表明对生长有有害影响。我们的研究结果表明，重金属污染已经到达深海沉积物，并证实了人类活动对深海的长期影响。分类多样性和生物特征（生活策略和营养成分）构成了底栖健康的强大生物指标和该地区未来潜在干扰的基准。古巴西北部斜坡仍然是古巴政府研究不足的部分，需要更多的研究来充分了解其生物多样性和生物地球化学模式。