Abstract Terpenoid hydrocarbons are ubiquitous in the marine environment and may be linked to natural synthetic activities after the original carbon skeleton of the biological precursor is retained. The terpenoid profile in pristine environments should have a biogenic signature. However, the widespread use of petroleum-derived products contributes to the inventory of hydrocarbons found in recent sediments, including the introduction of cyclic hydrocarbons with a thermogenic signature. Terpenoid hydrocarbons were examined from the mangrove sediments of the Paranagua Estuarine System (PES), which is a subtropical system in the South Atlantic. Intensive tourism has affected the PES, and it is at high risk of contamination due to extensive urban development and harbour activity. The biogenic compounds (BIO) in the PES were predominantly composed of unsaturated derivatives from higher plants (oleanoids, lupanoids, ursanoids and taraxeroids) with a des-A configuration and bacterial hopanoids. Thermogenic compounds (TRM) were distributed throughout the PES, and the sum of thermogenic and biogenic compounds exhibited a similar distribution, with significant correlations between these compounds. To better assess anthropogenic sources of hydrocarbons in mangrove, a ratio of TRM/BIO was proposed. Ratios higher than 1.0 were found near Paranagua port and in the Paranagua bay area. An important touristic destination, Mel Island, also exhibited ratios higher than 1.0 in two locations. The proposed terpenoids ratio accurately assessed the low-level chronic inputs of anthropogenic hydrocarbons in the study area. This innovative approach may be applied to areas with high biogenic inputs of organic matter, where chronic low-level hydrocarbon contributions are not evident using n-alkanes and polycyclic aromatic hydrocarbons.

中文翻译：

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生物成因和热成因萜类烃作为潜在的地球化学工具，用于研究亚热带红树林沼泽中的沉积有机质

摘要 萜类烃类化合物在海洋环境中普遍存在，在保留了生物前体的原始碳骨架后，可能与自然合成活动有关。原始环境中的萜类化合物应该具有生物特征。然而，石油衍生产品的广泛使用有助于在最近的沉积物中发现碳氢化合物的清单，包括引入具有热成因特征的环状碳氢化合物。从巴拉那瓜河口系统 (PES) 的红树林沉积物中检测了萜类烃，该系统是南大西洋的一个亚热带系统。集约旅游已经影响了 PES，并且由于广泛的城市开发和港口活动，它处于高污染风险中。PES 中的生物源化合物 (BIO) 主要由来自具有 des-A 构型的高等植物（类油树脂、羽扇豆类、熊果类和蒲公英类）的不饱和衍生物和细菌 hopanoids 组成。产热化合物 (TRM) 分布在整个 PES，产热和生物化合物的总和表现出相似的分布，这些化合物之间具有显着的相关性。为了更好地评估红树林中碳氢化合物的人为来源，提出了 TRM/BIO 的比率。在巴拉那瓜港口附近和巴拉那瓜湾地区发现了高于 1.0 的比率。重要的旅游目的地梅尔岛在两个地方的比率也高于 1.0。拟议的萜类化合物比例准确评估了研究区人为碳氢化合物的低水平慢性输入。